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author | William Joye <wjoye@cfa.harvard.edu> | 2019-05-10 16:18:58 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2019-05-10 16:18:58 (GMT) |
commit | 5492ad5105428df25cca70ab260229f757427278 (patch) | |
tree | e2bc900ba8c297d483518d1e86405e2e0f86f0ea /ast/polygon.c | |
parent | 9646e8d50bc1481de77459d59738826f9c256ad6 (diff) | |
download | blt-5492ad5105428df25cca70ab260229f757427278.zip blt-5492ad5105428df25cca70ab260229f757427278.tar.gz blt-5492ad5105428df25cca70ab260229f757427278.tar.bz2 |
upgrade ast 8.7.1
Diffstat (limited to 'ast/polygon.c')
-rw-r--r-- | ast/polygon.c | 7086 |
1 files changed, 7086 insertions, 0 deletions
diff --git a/ast/polygon.c b/ast/polygon.c new file mode 100644 index 0000000..80b42ff --- /dev/null +++ b/ast/polygon.c @@ -0,0 +1,7086 @@ +/* +*class++ +* Name: +* Polygon + +* Purpose: +* A polygonal region within a 2-dimensional Frame. + +* Constructor Function: +c astPolygon +f AST_POLYGON + +* Description: +* The Polygon class implements a polygonal area, defined by a +* collection of vertices, within a 2-dimensional Frame. The vertices +* are connected together by geodesic curves within the encapsulated Frame. +* For instance, if the encapsulated Frame is a simple Frame then the +* geodesics will be straight lines, but if the Frame is a SkyFrame then +* the geodesics will be great circles. Note, the vertices must be +* supplied in an order such that the inside of the polygon is to the +* left of the boundary as the vertices are traversed. Supplying them +* in the reverse order will effectively negate the polygon. +* +* Within a SkyFrame, neighbouring vertices are always joined using the +* shortest path. Thus if an edge of 180 degrees or more in length is +* required, it should be split into section each of which is less +* than 180 degrees. The closed path joining all the vertices in order +* will divide the celestial sphere into two disjoint regions. The +* inside of the polygon is the region which is circled in an +* anti-clockwise manner (when viewed from the inside of the celestial +* sphere) when moving through the list of vertices in the order in +* which they were supplied when the Polygon was created (i.e. the +* inside is to the left of the boundary when moving through the +* vertices in the order supplied). + +* Inheritance: +* The Polygon class inherits from the Region class. + +* Attributes: +* In addition to those attributes common to all Regions, every +* Polygon also has the following attributes: +* - SimpVertices: Simplify by transforming the vertices? + +* Functions: +c In addition to those functions applicable to all Regions, the +c following functions may also be applied to all Polygons: +f In addition to those routines applicable to all Regions, the +f following routines may also be applied to all Polygons: +* +c - astDownsize: Reduce the number of vertices in a Polygon. +f - AST_DOWNSIZE: Reduce the number of vertices in a Polygon. +c - astConvex<X>: Create a Polygon giving the convex hull of a pixel array +f - AST_CONVEX<X>: Create a Polygon giving the convex hull of a pixel array +c - astOutline<X>: Create a Polygon outlining values in a pixel array +f - AST_OUTLINE<X>: Create a Polygon outlining values in a pixel array + +* Copyright: +* Copyright (C) 1997-2006 Council for the Central Laboratory of the +* Research Councils +* Copyright (C) 2009 Science & Technology Facilities Council. +* All Rights Reserved. + +* Licence: +* This program is free software: you can redistribute it and/or +* modify it under the terms of the GNU Lesser General Public +* License as published by the Free Software Foundation, either +* version 3 of the License, or (at your option) any later +* version. +* +* This program is distributed in the hope that it will be useful, +* but WITHOUT ANY WARRANTY; without even the implied warranty of +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +* GNU Lesser General Public License for more details. +* +* You should have received a copy of the GNU Lesser General +* License along with this program. If not, see +* <http://www.gnu.org/licenses/>. + +* Authors: +* DSB: David S. Berry (Starlink) + +* History: +* 26-OCT-2004 (DSB): +* Original version. +* 28-MAY-2009 (DSB): +* Added astDownsize. +* 29-MAY-2009 (DSB): +* Added astOutline<X>. +* 30-JUN-2009 (DSB): +* Override astGetBounded. +* 4-NOV-2013 (DSB): +* Modify RegPins so that it can handle uncertainty regions that straddle +* a discontinuity. Previously, such uncertainty Regions could have a huge +* bounding box resulting in matching region being far too big. +* 6-DEC-2013 (DSB): +* Reverse the order of the vertices when the Polygon is created, +* if necessary, to ensure that the unnegated Polygon is bounded. +* The parent Region class assumes that unnegated regions are +* bounded. +* 6-JAN-2014 (DSB): +* Free edges when clearing the cache, not when establishing a new +* cache, as the number of edges may have changed. +* 10-JAN-2014 (DSB): +* - Remove unused parameter description in prologue of for astOutline<X> +* 24-FEB-2014 (DSB): +* Added astConvex<X>. +* 25-FEB-2014 (DSB): +* Added attribute SimpVertices. +* 7-SEP-2015 (DSB): +* Shrink outline polygons by a small fraction of a pixel, in order +* to avoid placing vertices exactly on pixel edges. This is because +* rounding errors in subsequent code may push the vertices into +* neighbouring pixels, which may have bad WCS coords (e.g. +* vertices on the boundary of a polar cusp in an HPX map). +*class-- +*/ + +/* Module Macros. */ +/* ============== */ +/* Set the name of the class we are implementing. This indicates to + the header files that define class interfaces that they should make + "protected" symbols available. */ +#define astCLASS Polygon + +/* Define a macro for testing if a pixel value <V> satisfies the requirements + specified by <Oper> and <Value>. Compiler optimisation should remove + all the "if" testing from this expression. */ +#define ISVALID(V,OperI,Value) ( \ + ( OperI == AST__LT ) ? ( (V) < Value ) : ( \ + ( OperI == AST__LE ) ? ( (V) <= Value ) : ( \ + ( OperI == AST__EQ ) ? ( (V) == Value ) : ( \ + ( OperI == AST__GE ) ? ( (V) >= Value ) : ( \ + ( OperI == AST__NE ) ? ( (V) != Value ) : ( \ + (V) > Value \ + ) \ + ) \ + ) \ + ) \ + ) \ +) + +/* Macros specifying whether a point is inside, outside or on the + boundary of the polygon. */ +#define UNKNOWN 0 +#define IN 1 +#define OUT 2 +#define ON 3 + +/* Size of pertubation (in pixels) used to avoid placing vertices exactly + on a pixel edge. */ +#define DELTA 0.01 + +/* Include files. */ +/* ============== */ +/* Interface definitions. */ +/* ---------------------- */ + +#include "globals.h" /* Thread-safe global data access */ +#include "error.h" /* Error reporting facilities */ +#include "memory.h" /* Memory allocation facilities */ +#include "object.h" /* Base Object class */ +#include "pointset.h" /* Sets of points/coordinates */ +#include "region.h" /* Coordinate regions (parent class) */ +#include "channel.h" /* I/O channels */ +#include "box.h" /* Box Regions */ +#include "wcsmap.h" /* Definitons of AST__DPI etc */ +#include "polygon.h" /* Interface definition for this class */ +#include "mapping.h" /* Position mappings */ +#include "unitmap.h" /* Unit Mapping */ +#include "pal.h" /* SLALIB library interface */ +#include "frame.h" /* Coordinate system description */ + +/* Error code definitions. */ +/* ----------------------- */ +#include "ast_err.h" /* AST error codes */ + +/* C header files. */ +/* --------------- */ +#include <float.h> +#include <math.h> +#include <stdarg.h> +#include <stdlib.h> +#include <stddef.h> +#include <stdio.h> +#include <string.h> +#include <limits.h> + +/* Type definitions. */ +/* ================= */ + +/* A structure that holds information about an edge of the new Polygon + being created by astDownsize. The edge is a line betweeen two of the + vertices of the original Polygon. */ +typedef struct Segment { + int i1; /* Index of starting vertex within old Polygon */ + int i2; /* Index of ending vertex within old Polygon */ + double error; /* Max geodesic distance from any old vertex to the line */ + int imax; /* Index of the old vertex at which max error is reached */ + struct Segment *next;/* Pointer to next Segment in a double link list */ + struct Segment *prev;/* Pointer to previous Segment in a double link list */ +} Segment; + + +/* Module Variables. */ +/* ================= */ + +/* Address of this static variable is used as a unique identifier for + member of this class. */ +static int class_check; + +/* Pointers to parent class methods which are extended by this class. */ +static AstPointSet *(* parent_transform)( AstMapping *, AstPointSet *, int, AstPointSet *, int * ); +static AstMapping *(* parent_simplify)( AstMapping *, int * ); +static void (* parent_setregfs)( AstRegion *, AstFrame *, int * ); +static void (* parent_resetcache)( AstRegion *, int * ); +static const char *(* parent_getattrib)( AstObject *, const char *, int * ); +static int (* parent_testattrib)( AstObject *, const char *, int * ); +static void (* parent_clearattrib)( AstObject *, const char *, int * ); +static void (* parent_setattrib)( AstObject *, const char *, int * ); + + +#ifdef THREAD_SAFE +/* Define how to initialise thread-specific globals. */ +#define GLOBAL_inits \ + globals->Class_Init = 0; \ + globals->GetAttrib_Buff[ 0 ] = 0; + +/* Create the function that initialises global data for this module. */ +astMAKE_INITGLOBALS(Polygon) + +/* Define macros for accessing each item of thread specific global data. */ +#define class_init astGLOBAL(Polygon,Class_Init) +#define class_vtab astGLOBAL(Polygon,Class_Vtab) +#define getattrib_buff astGLOBAL(Polygon,GetAttrib_Buff) + + +#include <pthread.h> + + +#else + +static char getattrib_buff[ 51 ]; + +/* Define the class virtual function table and its initialisation flag + as static variables. */ +static AstPolygonVtab class_vtab; /* Virtual function table */ +static int class_init = 0; /* Virtual function table initialised? */ + +#endif + +/* External Interface Function Prototypes. */ +/* ======================================= */ +/* The following functions have public prototypes only (i.e. no + protected prototypes), so we must provide local prototypes for use + within this module. */ +AstPolygon *astPolygonId_( void *, int, int, const double *, void *, const char *, ... ); + +/* Prototypes for Private Member Functions. */ +/* ======================================== */ + +/* Define a macro that expands to a single prototype for function + FindInsidePoint for a given data type and operation. */ +#define FINDINSIDEPOINT_PROTO0(X,Xtype,Oper) \ +static void FindInsidePoint##Oper##X( Xtype, const Xtype *, const int[2], const int[2], int *, int *, int *, int * ); + +/* Define a macro that expands to a set of prototypes for all operations + for function FindInsidePoint for a given data type. */ +#define FINDINSIDEPOINT_PROTO(X,Xtype) \ +FINDINSIDEPOINT_PROTO0(X,Xtype,LT) \ +FINDINSIDEPOINT_PROTO0(X,Xtype,LE) \ +FINDINSIDEPOINT_PROTO0(X,Xtype,EQ) \ +FINDINSIDEPOINT_PROTO0(X,Xtype,GE) \ +FINDINSIDEPOINT_PROTO0(X,Xtype,GT) \ +FINDINSIDEPOINT_PROTO0(X,Xtype,NE) + +/* Use the above macros to define all FindInsidePoint prototypes for all + data types and operations. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +FINDINSIDEPOINT_PROTO(LD,long double) +#endif +FINDINSIDEPOINT_PROTO(D,double) +FINDINSIDEPOINT_PROTO(L,long int) +FINDINSIDEPOINT_PROTO(UL,unsigned long int) +FINDINSIDEPOINT_PROTO(I,int) +FINDINSIDEPOINT_PROTO(UI,unsigned int) +FINDINSIDEPOINT_PROTO(S,short int) +FINDINSIDEPOINT_PROTO(US,unsigned short int) +FINDINSIDEPOINT_PROTO(B,signed char) +FINDINSIDEPOINT_PROTO(UB,unsigned char) +FINDINSIDEPOINT_PROTO(F,float) + +/* Define a macro that expands to a single prototype for function + TraceEdge for a given data type and operation. */ +#define TRACEEDGE_PROTO0(X,Xtype,Oper) \ +static AstPointSet *TraceEdge##Oper##X( Xtype, const Xtype *, const int[2], const int[2], int, int, int, int, int, int * ); + +/* Define a macro that expands to a set of prototypes for all operations + for function TraceEdge for a given data type. */ +#define TRACEEDGE_PROTO(X,Xtype) \ +TRACEEDGE_PROTO0(X,Xtype,LT) \ +TRACEEDGE_PROTO0(X,Xtype,LE) \ +TRACEEDGE_PROTO0(X,Xtype,EQ) \ +TRACEEDGE_PROTO0(X,Xtype,GE) \ +TRACEEDGE_PROTO0(X,Xtype,GT) \ +TRACEEDGE_PROTO0(X,Xtype,NE) + +/* Use the above macros to define all TraceEdge prototypes for all + data types and operations. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +TRACEEDGE_PROTO(LD,long double) +#endif +TRACEEDGE_PROTO(D,double) +TRACEEDGE_PROTO(L,long int) +TRACEEDGE_PROTO(UL,unsigned long int) +TRACEEDGE_PROTO(I,int) +TRACEEDGE_PROTO(UI,unsigned int) +TRACEEDGE_PROTO(S,short int) +TRACEEDGE_PROTO(US,unsigned short int) +TRACEEDGE_PROTO(B,signed char) +TRACEEDGE_PROTO(UB,unsigned char) +TRACEEDGE_PROTO(F,float) + +/* Define a macro that expands to a single prototype for function + PartHull for a given data type and operation. */ +#define PARTHULL_PROTO0(X,Xtype,Oper) \ +static void PartHull##Oper##X( Xtype, const Xtype[], int, int, int, int, int, int, int, const int[2], double **, double **, int *, int * ); + +/* Define a macro that expands to a set of prototypes for all operations + for function PartHull for a given data type. */ +#define PARTHULL_PROTO(X,Xtype) \ +PARTHULL_PROTO0(X,Xtype,LT) \ +PARTHULL_PROTO0(X,Xtype,LE) \ +PARTHULL_PROTO0(X,Xtype,EQ) \ +PARTHULL_PROTO0(X,Xtype,GE) \ +PARTHULL_PROTO0(X,Xtype,GT) \ +PARTHULL_PROTO0(X,Xtype,NE) + +/* Use the above macros to define all PartHull prototypes for all + data types and operations. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +PARTHULL_PROTO(LD,long double) +#endif +PARTHULL_PROTO(D,double) +PARTHULL_PROTO(L,long int) +PARTHULL_PROTO(UL,unsigned long int) +PARTHULL_PROTO(I,int) +PARTHULL_PROTO(UI,unsigned int) +PARTHULL_PROTO(S,short int) +PARTHULL_PROTO(US,unsigned short int) +PARTHULL_PROTO(B,signed char) +PARTHULL_PROTO(UB,unsigned char) +PARTHULL_PROTO(F,float) + +/* Define a macro that expands to a single prototype for function + ConvexHull for a given data type and operation. */ +#define CONVEXHULL_PROTO0(X,Xtype,Oper) \ +static AstPointSet *ConvexHull##Oper##X( Xtype, const Xtype[], const int[2], int, int, int, int * ); + +/* Define a macro that expands to a set of prototypes for all operations + for function ConvexHull for a given data type. */ +#define CONVEXHULL_PROTO(X,Xtype) \ +CONVEXHULL_PROTO0(X,Xtype,LT) \ +CONVEXHULL_PROTO0(X,Xtype,LE) \ +CONVEXHULL_PROTO0(X,Xtype,EQ) \ +CONVEXHULL_PROTO0(X,Xtype,GE) \ +CONVEXHULL_PROTO0(X,Xtype,GT) \ +CONVEXHULL_PROTO0(X,Xtype,NE) + +/* Use the above macros to define all ConvexHull prototypes for all + data types and operations. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +CONVEXHULL_PROTO(LD,long double) +#endif +CONVEXHULL_PROTO(D,double) +CONVEXHULL_PROTO(L,long int) +CONVEXHULL_PROTO(UL,unsigned long int) +CONVEXHULL_PROTO(I,int) +CONVEXHULL_PROTO(UI,unsigned int) +CONVEXHULL_PROTO(S,short int) +CONVEXHULL_PROTO(US,unsigned short int) +CONVEXHULL_PROTO(B,signed char) +CONVEXHULL_PROTO(UB,unsigned char) +CONVEXHULL_PROTO(F,float) + +/* Define a macro that expands to a single prototype for function + FindBoxEdge for a given data type and operation. */ +#define FINDBOXEDGE_PROTO0(X,Xtype,Oper) \ +static void FindBoxEdge##Oper##X( Xtype, const Xtype[], int, int, int, int, int *, int *, int *, int * ); + +/* Define a macro that expands to a set of prototypes for all operations + for function FindBoxEdge for a given data type. */ +#define FINDBOXEDGE_PROTO(X,Xtype) \ +FINDBOXEDGE_PROTO0(X,Xtype,LT) \ +FINDBOXEDGE_PROTO0(X,Xtype,LE) \ +FINDBOXEDGE_PROTO0(X,Xtype,EQ) \ +FINDBOXEDGE_PROTO0(X,Xtype,GE) \ +FINDBOXEDGE_PROTO0(X,Xtype,GT) \ +FINDBOXEDGE_PROTO0(X,Xtype,NE) + +/* Use the above macros to define all FindBoxEdge prototypes for all + data types and operations. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +FINDBOXEDGE_PROTO(LD,long double) +#endif +FINDBOXEDGE_PROTO(D,double) +FINDBOXEDGE_PROTO(L,long int) +FINDBOXEDGE_PROTO(UL,unsigned long int) +FINDBOXEDGE_PROTO(I,int) +FINDBOXEDGE_PROTO(UI,unsigned int) +FINDBOXEDGE_PROTO(S,short int) +FINDBOXEDGE_PROTO(US,unsigned short int) +FINDBOXEDGE_PROTO(B,signed char) +FINDBOXEDGE_PROTO(UB,unsigned char) +FINDBOXEDGE_PROTO(F,float) + + + + + + + + + +/* Non-generic function prototypes. */ +static AstMapping *Simplify( AstMapping *, int * ); +static AstPointSet *DownsizePoly( AstPointSet *, double, int, AstFrame *, int * ); +static AstPointSet *RegBaseMesh( AstRegion *, int * ); +static AstPointSet *Transform( AstMapping *, AstPointSet *, int, AstPointSet *, int * ); +static AstPolygon *Downsize( AstPolygon *, double, int, int * ); +static Segment *AddToChain( Segment *, Segment *, int * ); +static Segment *NewSegment( Segment *, int, int, int, int * ); +static Segment *RemoveFromChain( Segment *, Segment *, int * ); +static double Polywidth( AstFrame *, AstLineDef **, int, int, double[ 2 ], int * ); +static int GetBounded( AstRegion *, int * ); +static int IntCmp( const void *, const void * ); +static int RegPins( AstRegion *, AstPointSet *, AstRegion *, int **, int * ); +static int RegTrace( AstRegion *, int, double *, double **, int * ); +static void Cache( AstPolygon *, int * ); +static void Copy( const AstObject *, AstObject *, int * ); +static void Delete( AstObject *, int * ); +static void Dump( AstObject *, AstChannel *, int * ); +static void EnsureInside( AstPolygon *, int * ); +static void FindMax( Segment *, AstFrame *, double *, double *, int, int, int * ); +static void RegBaseBox( AstRegion *this, double *, double *, int * ); +static void ResetCache( AstRegion *this, int * ); +static void SetPointSet( AstPolygon *, AstPointSet *, int * ); +static void SetRegFS( AstRegion *, AstFrame *, int * ); +static void SmoothPoly( AstPointSet *, int, double, int * ); + +static const char *GetAttrib( AstObject *, const char *, int * ); +static void ClearAttrib( AstObject *, const char *, int * ); +static void SetAttrib( AstObject *, const char *, int * ); +static int TestAttrib( AstObject *, const char *, int * ); + +static int GetSimpVertices( AstPolygon *, int * ); +static int TestSimpVertices( AstPolygon *, int * ); +static void ClearSimpVertices( AstPolygon *, int * ); +static void SetSimpVertices( AstPolygon *, int, int * ); + + +/* Member functions. */ +/* ================= */ +static Segment *AddToChain( Segment *head, Segment *seg, int *status ){ +/* +* Name: +* AddToChain + +* Purpose: +* Add a Segment into the linked list of Segments, maintaining the +* required order in the list. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* Segment *AddToChain( Segment *head, Segment *seg, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* The linked list of Segments maintained by astDownsize is searched +* from the high error end (the head), until a Segment is foound which +* has a lower error than the supplied segment. The supplied Segment +* is then inserted into the list at that point. + +* Parameters: +* head +* The Segment structure at the head of the list (i.e. the segment +* with maximum error). +* seg +* The Segment to be added into the list. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Pointer to the link head (which will have changed if "seg" has a +* higher error than the original head). + +*/ + +/* Local Variables: */ + Segment *tseg; + +/* Check the global error status. */ + if ( !astOK ) return head; + +/* If the list is empty, return the supplied segment as the new list + head. */ + if( !head ) { + head = seg; + +/* If the supplied segment has a higher error than the original head, + insert the new segment in front of the original head. */ + } else if( seg->error > head->error ){ + seg->next = head; + head->prev = seg; + head = seg; + +/* Otherwise, move down the list from the head until a segment is found + which has a lower error than the supplied Segment. Then insert the + supplied segment into the list in front of it. */ + } else { + tseg = head; + seg->next = NULL; + + while( tseg->next ) { + if( seg->error > tseg->next->error ) { + seg->next = tseg->next; + seg->prev = tseg; + tseg->next->prev = seg; + tseg->next = seg; + break; + } + tseg = tseg->next; + } + + if( !seg->next ) { + tseg->next = seg; + seg->prev = tseg; + } + } + +/* Return the new head. */ + return head; +} + +static void Cache( AstPolygon *this, int *status ){ +/* +* Name: +* Cache + +* Purpose: +* Calculate intermediate values and cache them in the Polygon structure. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void Cache( AstPolygon *this, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function uses the PointSet stored in the parent Region to calculate +* some intermediate values which are useful in other methods. These +* values are stored within the Polygon structure. + +* Parameters: +* this +* Pointer to the Polygon. +* status +* Pointer to the inherited status variable. + +*/ + +/* Local Variables: */ + AstFrame *frm; /* Pointer to base Frame in Polygon */ + double **ptr; /* Pointer to data in the encapsulated PointSet */ + double end[ 2 ]; /* Start position for edge */ + double maxwid; /* Maximum polygon width found so far */ + double polcen[ 2 ]; /* Polygon centre perpendicular to current edge */ + double polwid; /* Polygon width perpendicular to current edge */ + double start[ 2 ]; /* Start position for edge */ + int i; /* Axis index */ + int nv; /* Number of vertices in Polygon */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Do nothing if the cached information is up to date. */ + if( this->stale ) { + +/* Get a pointer to the base Frame. */ + frm = astGetFrame( ((AstRegion *) this)->frameset, AST__BASE ); + +/* Get the number of vertices. */ + nv = astGetNpoint( ((AstRegion *) this)->points ); + +/* Get pointers to the coordinate data in the parent Region structure. */ + ptr = astGetPoints( ((AstRegion *) this)->points ); + +/* Free any existing edge information in the Polygon structure. */ + if( this->edges ) { + for( i = 0; i < nv; i++ ) { + this->edges[ i ] = astFree( this->edges[ i ] ); + } + } + +/* Ensure we have enough memory to store new edge information if necessary. */ + this->edges = astGrow( this->edges, nv, sizeof( AstLineDef *) ); + this->startsat = astGrow( this->startsat, nv, sizeof( double ) ); + +/* Check pointers can be used safely. */ + if( this->edges && this->startsat ) { + +/* Create and store a description of each edge. Also form the total + distance round the polygon, and the distance from the first vertex + at which each edge starts. */ + this->totlen = 0.0; + start[ 0 ] = ptr[ 0 ][ nv - 1 ]; + start[ 1 ] = ptr[ 1 ][ nv - 1 ]; + + for( i = 0; i < nv; i++ ) { + end[ 0 ] = ptr[ 0 ][ i ]; + end[ 1 ] = ptr[ 1 ][ i ]; + this->edges[ i ] = astLineDef( frm, start, end ); + start[ 0 ] = end[ 0 ]; + start[ 1 ] = end[ 1 ]; + + this->startsat[ i ] = this->totlen; + this->totlen += this->edges[ i ]->length; + } + +/* We now look for a point that is inside the polygon. We want a point + that is well within the polygon, since points that are only just inside + the polygon can give numerical problems. Loop round each edge with + non-zero length. */ + maxwid = -1.0; + for( i = 0; i < nv; i++ ) { + if( this->edges[ i ]->length > 0.0 ) { + +/* We define another line perpendicular to the current edge, passing + through the mid point of the edge, extending towards the inside of the + polygon. The following function returns the distance we can travel + along this line before we hit any of the other polygon edges. It also + puts the position corresponding to half that distance into "polcen". */ + polwid = Polywidth( frm, this->edges, i, nv, polcen, status ); + +/* If the width of the polygon perpendicular to the current edge is + greater than the width perpdeicular to any other edge, record the + width and also store the current polygon centre. */ + if( polwid > maxwid && polwid != AST__BAD ) { + maxwid = polwid; + (this->in)[ 0 ] = polcen[ 0 ]; + (this->in)[ 1 ] = polcen[ 1 ]; + } + } + } + +/* If no width was found it probably means that the polygon vertices were + given in clockwise order, resulting in the above process probing the + infinite extent outside the polygonal hole. In this case any point + outside the hole will do, so we use the current contents of the + "polcen" array. Set a flag indicating if the vertices are stored in + anti-clockwise order. */ + if( maxwid < 0.0 ) { + (this->in)[ 0 ] = polcen[ 0 ]; + (this->in)[ 1 ] = polcen[ 1 ]; + this->acw = 0; + } else { + this->acw = 1; + } + } + +/* Free resources */ + frm = astAnnul( frm ); + +/* Indicate cached information is up to date. */ + this->stale = 0; + } +} + +static void ClearAttrib( AstObject *this_object, const char *attrib, int *status ) { +/* +* Name: +* ClearAttrib + +* Purpose: +* Clear an attribute value for a Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void ClearAttrib( AstObject *this, const char *attrib, int *status ) + +* Class Membership: +* Polygon member function (over-rides the astClearAttrib protected +* method inherited from the Region class). + +* Description: +* This function clears the value of a specified attribute for a +* Polygon, so that the default value will subsequently be used. + +* Parameters: +* this +* Pointer to the Polygon. +* attrib +* Pointer to a null terminated string specifying the attribute +* name. This should be in lower case with no surrounding white +* space. +* status +* Pointer to the inherited status variable. +*/ + +/* Local Variables: */ + AstPolygon *this; /* Pointer to the Polygon structure */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) this_object; + +/* Check the attribute name and clear the appropriate attribute. */ + +/* SimpVertices. */ +/* ------------- */ + if ( !strcmp( attrib, "simpvertices" ) ) { + astClearSimpVertices( this ); + +/* If the attribute is not recognised, pass it on to the parent method + for further interpretation. */ + } else { + (*parent_clearattrib)( this_object, attrib, status ); + } +} + +/* +*++ +* Name: +c astConvex<X> +f AST_CONVEX<X> + +* Purpose: +* Create a new Polygon representing the convex hull of a 2D data grid. + +* Type: +* Public function. + +* Synopsis: +c #include "polygon.h" +c AstPolygon *astConvex<X>( <Xtype> value, int oper, const <Xtype> array[], +c const int lbnd[2], const int ubnd[2], int starpix ) +f RESULT = AST_CONVEX<X>( VALUE, OPER, ARRAY, LBND, UBND, STARPIX, STATUS ) + +* Class Membership: +* Polygon method. + +* Description: +* This is a set of functions that create the shortest Polygon that +* encloses all pixels with a specified value within a gridded +* 2-dimensional data array (e.g. an image). +* +* A basic 2-dimensional Frame is used to represent the pixel coordinate +* system in the returned Polygon. The Domain attribute is set to +* "PIXEL", the Title attribute is set to "Pixel coordinates", and the +* Unit attribute for each axis is set to "pixel". All other +* attributes are left unset. The nature of the pixel coordinate system +* is determined by parameter +c "starpix". +f STARPIX. +* +* You should use a function which matches the numerical type of the +* data you are processing by replacing <X> in the generic function +* name +c astConvex<X> +f AST_CONVEX<X> +c by an appropriate 1- or 2-character type code. For example, if you +* are procesing data with type +c "float", you should use the function astConvexF +f REAL, you should use the function AST_CONVEXR +* (see the "Data Type Codes" section below for the codes appropriate to +* other numerical types). + +* Parameters: +c value +f VALUE = <Xtype> (Given) +* A data value that specifies the pixels to be included within the +* convex hull. +c oper +f OPER = INTEGER (Given) +* Indicates how the +c "value" +f VALUE +* parameter is used to select the required pixels. It can +* have any of the following values: +c - AST__LT: include pixels with value less than "value". +c - AST__LE: include pixels with value less than or equal to "value". +c - AST__EQ: include pixels with value equal to "value". +c - AST__NE: include pixels with value not equal to "value". +c - AST__GE: include pixels with value greater than or equal to "value". +c - AST__GT: include pixels with value greater than "value". +f - AST__LT: include pixels with value less than VALUE. +f - AST__LE: include pixels with value less than or equal to VALUE. +f - AST__EQ: include pixels with value equal to VALUE. +f - AST__NE: include pixels with value not equal to VALUE. +f - AST__GE: include pixels with value greater than or equal to VALUE. +f - AST__GT: include pixels with value greater than VALUE. +c array +f ARRAY( * ) = <Xtype> (Given) +c Pointer to a +f A +* 2-dimensional array containing the data to be processed. The +* numerical type of this array should match the 1- or +* 2-character type code appended to the function name (e.g. if +c you are using astConvexF, the type of each array element +c should be "float"). +f you are using AST_CONVEXR, the type of each array element +f should be REAL). +* +* The storage order of data within this array should be such +* that the index of the first grid dimension varies most +* rapidly and that of the second dimension least rapidly +c (i.e. Fortran array indexing is used). +f (i.e. normal Fortran array storage order). +c lbnd +f LBND( 2 ) = INTEGER (Given) +c Pointer to an array of two integers +f An array +* containing the coordinates of the centre of the first pixel +* in the input grid along each dimension. +c ubnd +f UBND( 2) = INTEGER (Given) +c Pointer to an array of two integers +f An array +* containing the coordinates of the centre of the last pixel in +* the input grid along each dimension. +* +c Note that "lbnd" and "ubnd" together define the shape +f Note that LBND and UBND together define the shape +* and size of the input grid, its extent along a particular +c (j'th) dimension being ubnd[j]-lbnd[j]+1 (assuming the +c index "j" to be zero-based). They also define +f (J'th) dimension being UBND(J)-LBND(J)+1. They also define +* the input grid's coordinate system, each pixel having unit +* extent along each dimension with integral coordinate values +* at its centre or upper corner, as selected by parameter +c "starpix". +f STARPIX. +c starpix +f STARPIX = LOGICAL (Given) +* A flag indicating the nature of the pixel coordinate system used +* to describe the vertex positions in the returned Polygon. If +c non-zero, +f .TRUE., +* the standard Starlink definition of pixel coordinate is used in +* which a pixel with integer index I spans a range of pixel coordinate +* from (I-1) to I (i.e. pixel corners have integral pixel coordinates). +c If zero, +f If .FALSE., +* the definition of pixel coordinate used by other AST functions +c such as astResample, astMask, +f such as AST_RESAMPLE, AST_MASK, +* etc., is used. In this definition, a pixel with integer index I +* spans a range of pixel coordinate from (I-0.5) to (I+0.5) (i.e. +* pixel centres have integral pixel coordinates). +f STATUS = INTEGER (Given and Returned) +f The global status. + +* Returned Value: +c astConvex<X>() +f AST_CONVEX<X> = INTEGER +* A pointer to the required Polygon. +c NULL +f AST__NULL +* is returned without error if the array contains no pixels that +* satisfy the criterion specified by +c "value" and "oper". +f VALUE and OPER. + +* Notes: +c - NULL +f - AST__NULL +* will be returned if this function is invoked with the global +* error status set, or if it should fail for any reason. + +* Data Type Codes: +* To select the appropriate masking function, you should +c replace <X> in the generic function name astConvex<X> with a +f replace <X> in the generic function name AST_CONVEX<X> with a +* 1- or 2-character data type code, so as to match the numerical +* type <Xtype> of the data you are processing, as follows: +c - D: double +c - F: float +c - L: long int +c - UL: unsigned long int +c - I: int +c - UI: unsigned int +c - S: short int +c - US: unsigned short int +c - B: byte (signed char) +c - UB: unsigned byte (unsigned char) +f - D: DOUBLE PRECISION +f - R: REAL +f - I: INTEGER +f - UI: INTEGER (treated as unsigned) +f - S: INTEGER*2 (short integer) +f - US: INTEGER*2 (short integer, treated as unsigned) +f - B: BYTE (treated as signed) +f - UB: BYTE (treated as unsigned) +* +c For example, astConvexD would be used to process "double" +c data, while astConvexS would be used to process "short int" +c data, etc. +f For example, AST_CONVEXD would be used to process DOUBLE +f PRECISION data, while AST_CONVEXS would be used to process +f short integer data (stored in an INTEGER*2 array), etc. +f +f For compatibility with other Starlink facilities, the codes W +f and UW are provided as synonyms for S and US respectively (but +f only in the Fortran interface to AST). + +*-- +*/ +/* Define a macro to implement the function for a specific data + type. Note, this function cannot be a virtual function since the + argument list does not include a Polygon, and so no virtual function + table is available. */ +#define MAKE_CONVEX(X,Xtype) \ +AstPolygon *astConvex##X##_( Xtype value, int oper, const Xtype array[], \ + const int lbnd[2], const int ubnd[2], \ + int starpix, int *status ) { \ +\ +/* Local Variables: */ \ + AstFrame *frm; /* Frame in which to define the Polygon */ \ + AstPointSet *candidate; /* Candidate polygon vertices */ \ + AstPolygon *result; /* Result value to return */ \ + int xdim; /* Number of pixels per row */ \ + int ydim; /* Number of rows */ \ + static double junk[ 6 ] = {0.0, 0.0, 1.0, 1.0, 0.0, 1.0 }; /* Junk poly */ \ +\ +/* Initialise. */ \ + result = NULL; \ + candidate = NULL; \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return result; \ +\ +/* Get the array dimensions. */ \ + xdim = ubnd[ 0 ] - lbnd[ 0 ] + 1; \ + ydim = ubnd[ 1 ] - lbnd[ 1 ] + 1; \ +\ +/* Get the basic concvex hull. */ \ + if( oper == AST__LT ) { \ + candidate = ConvexHullLT##X( value, array, lbnd, starpix, xdim, ydim, status ); \ +\ + } else if( oper == AST__LE ) { \ + candidate = ConvexHullLE##X( value, array, lbnd, starpix, xdim, ydim, status ); \ +\ + } else if( oper == AST__EQ ) { \ + candidate = ConvexHullEQ##X( value, array, lbnd, starpix, xdim, ydim, status ); \ +\ + } else if( oper == AST__NE ) { \ + candidate = ConvexHullNE##X( value, array, lbnd, starpix, xdim, ydim, status ); \ +\ + } else if( oper == AST__GE ) { \ + candidate = ConvexHullGE##X( value, array, lbnd, starpix, xdim, ydim, status ); \ +\ + } else if( oper == AST__GT ) { \ + candidate = ConvexHullGT##X( value, array, lbnd, starpix, xdim, ydim, status ); \ +\ + } else if( astOK ){ \ + astError( AST__OPRIN, "astConvex"#X": Invalid operation code " \ + "(%d) supplied (programming error).", status, oper ); \ + } \ +\ +/* Check some good selected values were found. */ \ + if( candidate ) { \ +\ +/* Create a default Polygon with 3 junk vertices. */ \ + frm = astFrame( 2, "Domain=PIXEL,Unit(1)=pixel,Unit(2)=pixel," \ + "Title=Pixel coordinates", status ); \ + result = astPolygon( frm, 3, 3, junk, NULL, " ", status ); \ +\ +/* Change the PointSet within the Polygon to the one created above. */ \ + SetPointSet( result, candidate, status ); \ +\ +/* Free resources. */ \ + frm = astAnnul( frm ); \ + candidate = astAnnul( candidate ); \ + } \ +\ +/* If an error occurred, clear the returned result. */ \ + if ( !astOK ) result = astAnnul( result ); \ +\ +/* Return the result. */ \ + return result; \ +} + + +/* Expand the above macro to generate a function for each required + data type. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKE_CONVEX(LD,long double) +#endif +MAKE_CONVEX(D,double) +MAKE_CONVEX(L,long int) +MAKE_CONVEX(UL,unsigned long int) +MAKE_CONVEX(I,int) +MAKE_CONVEX(UI,unsigned int) +MAKE_CONVEX(S,short int) +MAKE_CONVEX(US,unsigned short int) +MAKE_CONVEX(B,signed char) +MAKE_CONVEX(UB,unsigned char) +MAKE_CONVEX(F,float) + +/* Undefine the macros. */ +#undef MAKE_CONVEX + +/* +* Name: +* ConvexHull + +* Purpose: +* Find the convex hull enclosing selected pixels in a 2D array. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* AstPointSet *ConvexHull<Oper><X>( <Xtype> value, const <Xtype> array[], +* const int lbnd[2], int starpix, +* int xdim, int ydim, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function uses an algorithm similar to "Andrew's Monotone Chain +* Algorithm" to create a list of vertices describing the convex hull +* enclosing the selected pixels in the supplied array. The vertices +* are returned in a PointSet. + +* Parameters: +* value +* A data value that specifies the pixels to be selected. +* array +* Pointer to a 2-dimensional array containing the data to be +* processed. The numerical type of this array should match the 1- +* or 2-character type code appended to the function name. +* lbnd +* The lower pixel index bounds of the array. +* starpix +* If non-zero, the usual Starlink definition of pixel coordinate +* is used (integral values at pixel corners). Otherwise, the +* system used by other AST functions such as astResample is used +* (integral values at pixel centres). +* xdim +* The number of pixels along each row of the array. +* ydim +* The number of rows in the array. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* A PointSet holding the vertices of the convex hull, or NULL if an +* error occurs. + +* Notes: +* - The following code has been designed with a view to it being +* multi-threaded at some point. + +*/ + +/* Define a macro to implement the function for a specific data + type and operation. */ +#define MAKE_CONVEXHULL(X,Xtype,Oper,OperI) \ +static AstPointSet *ConvexHull##Oper##X( Xtype value, const Xtype array[], \ + const int lbnd[2], int starpix, \ + int xdim, int ydim, int *status ) { \ +\ +/* Local Variables: */ \ + AstPointSet *result; \ + double **ptr; \ + double *xv1; \ + double *xv2; \ + double *xv3; \ + double *xv4; \ + double *xvert; \ + double *yv1; \ + double *yv2; \ + double *yv3; \ + double *yv4; \ + double *yvert; \ + int nv1; \ + int nv2; \ + int nv3; \ + int nv4; \ + int nv; \ + int xhi; \ + int xhiymax; \ + int xhiymin; \ + int xlo; \ + int xloymax; \ + int xloymin; \ + int yhi; \ + int yhixmax; \ + int yhixmin; \ + int ylo; \ + int yloxmax; \ + int yloxmin; \ +\ +/* Initialise */ \ + result = NULL; \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return result; \ +\ +/* Find the lowest Y value at any selected pixel, and find the max and \ + min X value of the selected pixels at that lowest Y value. */ \ + FindBoxEdge##Oper##X( value, array, xdim, ydim, 1, 1, &ylo, &yloxmax, \ + &yloxmin, status ); \ +\ +/* Skip if there are no selected values in the array. */ \ + if( ylo > 0 ) { \ +\ +/* Find the highest Y value at any selected pixel, and find the max and \ + min X value of the selected pixels at that highest Y value. */ \ + FindBoxEdge##Oper##X( value, array, xdim, ydim, 1, 0, &yhi, &yhixmax, \ + &yhixmin, status ); \ +\ +/* Find the lowest X value at any selected pixel, and find the max and \ + min Y value of the selected pixels at that lowest X value. */ \ + FindBoxEdge##Oper##X( value, array, xdim, ydim, 0, 1, &xlo, &xloymax, \ + &xloymin, status ); \ +\ +/* Find the highest X value at any selected pixel, and find the max and \ + min Y value of the selected pixels at that highest X value. */ \ + FindBoxEdge##Oper##X( value, array, xdim, ydim, 0, 0, &xhi, &xhiymax, \ + &xhiymin, status ); \ +\ +/* Create a list of vertices for the bottom right corner of the bounding \ + box of the selected pixels. */ \ + PartHull##Oper##X( value, array, xdim, ydim, yloxmax, ylo, xhi, xhiymin, \ + starpix, lbnd, &xv1, &yv1, &nv1, status ); \ +\ +/* Create a list of vertices for the top right corner of the bounding \ + box of the selected pixels. */ \ + PartHull##Oper##X( value, array, xdim, ydim, xhi, xhiymax, yhixmax, yhi, \ + starpix, lbnd, &xv2, &yv2, &nv2, status ); \ +\ +/* Create a list of vertices for the top left corner of the bounding \ + box of the selected pixels. */ \ + PartHull##Oper##X( value, array, xdim, ydim, yhixmin, yhi, xlo, xloymax, \ + starpix, lbnd, &xv3, &yv3, &nv3, status ); \ +\ +/* Create a list of vertices for the bottom left corner of the bounding \ + box of the selected pixels. */ \ + PartHull##Oper##X( value, array, xdim, ydim, xlo, xloymin, yloxmin, ylo, \ + starpix, lbnd, &xv4, &yv4, &nv4, status ); \ +\ +/* Concatenate the four vertex lists and store them in the returned \ + PointSet. */ \ + nv = nv1 + nv2 + nv3 + nv4; \ + result = astPointSet( nv, 2, " ", status ); \ + ptr = astGetPoints( result ); \ + if( astOK ) { \ + xvert = ptr[ 0 ]; \ + yvert = ptr[ 1 ]; \ +\ + memcpy( xvert, xv1, nv1*sizeof( double ) ); \ + memcpy( yvert, yv1, nv1*sizeof( double ) ); \ + xvert += nv1; \ + yvert += nv1; \ +\ + memcpy( xvert, xv2, nv2*sizeof( double ) ); \ + memcpy( yvert, yv2, nv2*sizeof( double ) ); \ + xvert += nv2; \ + yvert += nv2; \ +\ + memcpy( xvert, xv3, nv3*sizeof( double ) ); \ + memcpy( yvert, yv3, nv3*sizeof( double ) ); \ + xvert += nv3; \ + yvert += nv3; \ +\ + memcpy( xvert, xv4, nv4*sizeof( double ) ); \ + memcpy( yvert, yv4, nv4*sizeof( double ) ); \ + } \ +\ +/* Free resources. */ \ + xv1 = astFree( xv1 ); \ + xv2 = astFree( xv2 ); \ + xv3 = astFree( xv3 ); \ + xv4 = astFree( xv4 ); \ + yv1 = astFree( yv1 ); \ + yv2 = astFree( yv2 ); \ + yv3 = astFree( yv3 ); \ + yv4 = astFree( yv4 ); \ + } \ +\ +/* Free the returned PointSet if an error occurred. */ \ + if( result && !astOK ) result = astAnnul( result ); \ +\ +/* Return the result. */ \ + return result; \ +} + +/* Define a macro that uses the above macro to to create implementations + of ConvexHull for all operations. */ +#define MAKEALL_CONVEXHULL(X,Xtype) \ +MAKE_CONVEXHULL(X,Xtype,LT,AST__LT) \ +MAKE_CONVEXHULL(X,Xtype,LE,AST__LE) \ +MAKE_CONVEXHULL(X,Xtype,EQ,AST__EQ) \ +MAKE_CONVEXHULL(X,Xtype,NE,AST__NE) \ +MAKE_CONVEXHULL(X,Xtype,GE,AST__GE) \ +MAKE_CONVEXHULL(X,Xtype,GT,AST__GT) + +/* Expand the above macro to generate a function for each required + data type and operation. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKEALL_CONVEXHULL(LD,long double) +#endif +MAKEALL_CONVEXHULL(D,double) +MAKEALL_CONVEXHULL(L,long int) +MAKEALL_CONVEXHULL(UL,unsigned long int) +MAKEALL_CONVEXHULL(I,int) +MAKEALL_CONVEXHULL(UI,unsigned int) +MAKEALL_CONVEXHULL(S,short int) +MAKEALL_CONVEXHULL(US,unsigned short int) +MAKEALL_CONVEXHULL(B,signed char) +MAKEALL_CONVEXHULL(UB,unsigned char) +MAKEALL_CONVEXHULL(F,float) + +/* Undefine the macros. */ +#undef MAKE_CONVEXHULL +#undef MAKEALL_CONVEXHULL + +static AstPolygon *Downsize( AstPolygon *this, double maxerr, int maxvert, + int *status ) { +/* +*++ +* Name: +c astDownsize +f AST_DOWNSIZE + +* Purpose: +* Reduce the number of vertices in a Polygon. + +* Type: +* Public virtual function. + +* Synopsis: +c #include "polygon.h" +c AstPolygon *astDownsize( AstPolygon *this, double maxerr, int maxvert ) +f RESULT = AST_DOWNSIZE( THIS, MAXERR, MAXVERT, STATUS ) + +* Class Membership: +* Polygon method. + +* Description: +* This function returns a pointer to a new Polygon that contains a +* subset of the vertices in the supplied Polygon. The subset is +* chosen so that the returned Polygon is a good approximation to +* the supplied Polygon, within the limits specified by the supplied +* parameter values. That is, the density of points in the returned +* Polygon is greater at points where the curvature of the boundary of +* the supplied Polygon is greater. + +* Parameters: +c this +f THIS = INTEGER (Given) +* Pointer to the Polygon. +c maxerr +f MAXERR = DOUBLE PRECISION (Given) +* The maximum allowed discrepancy between the supplied and +* returned Polygons, expressed as a geodesic distance within the +* Polygon's coordinate frame. If this is zero or less, the +* returned Polygon will have the number of vertices specified by +c maxvert. +f MAXVERT. +c maxvert +f MAXVERT = INTEGER (Given) +* The maximum allowed number of vertices in the returned Polygon. +* If this is less than 3, the number of vertices in the returned +* Polygon will be the minimum needed to achieve the maximum +* discrepancy specified by +c maxerr. +f MAXERR. +f STATUS = INTEGER (Given and Returned) +f The global status. + +* Returned Value: +c astDownsize() +f AST_DOWNSIZE = INTEGER +* Pointer to the new Polygon. + +* Notes: +* - A null Object pointer (AST__NULL) will be returned if this +c function is invoked with the AST error status set, or if it +f function is invoked with STATUS set to an error value, or if it +* should fail for any reason. +*-- +*/ + +/* Local Variables: */ + AstFrame *frm; /* Base Frame from the Polygon */ + AstPointSet *pset; /* PointSet holding vertices of downsized polygon */ + AstPolygon *result; /* Returned pointer to new Polygon */ + +/* Initialise. */ + result = NULL; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* Get a pointer to the base Frame of the Polygon. */ + frm = astGetFrame( ((AstRegion *) this)->frameset, AST__BASE ); + +/* Create a PointSet holding the vertices of the downsized polygon. */ + pset = DownsizePoly( ((AstRegion *) this)->points, maxerr, maxvert, + frm, status ); + +/* Take a deep copy of the supplied Polygon. */ + result = astCopy( this ); + +/* Change the PointSet within the result Polygon to the one created above. */ \ + SetPointSet( result, pset, status ); \ + +/* Free resources. */ + frm = astAnnul( frm ); + pset = astAnnul( pset ); + +/* If an error occurred, annul the returned Polygon. */ + if ( !astOK ) result = astAnnul( result ); + +/* Return the result. */ + return result; +} + +static AstPointSet *DownsizePoly( AstPointSet *pset, double maxerr, + int maxvert, AstFrame *frm, int *status ) { +/* +* Name: +* DownsizePoly + +* Purpose: +* Reduce the number of vertices in a Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* AstPointSet *DownsizePoly( AstPointSet *pset, double maxerr, int maxvert, +* AstFrame *frm, int *status ) + +* Class Membership: +* Polygon member function. + +* Description: +* This function returns a pointer to a new PointSet that contains a +* subset of the vertices in the supplied PointSet. The subset is +* chosen so that the returned polygon is a good approximation to +* the supplied polygon, within the limits specified by the supplied +* parameter values. That is, the density of points in the returned +* polygon is greater at points where the curvature of the boundary of +* the supplied polygon is greater. + +* Parameters: +* pset +* Pointer to the PointSet holding the polygon vertices. +* maxerr +* The maximum allowed discrepancy between the supplied and +* returned Polygons, expressed as a geodesic distance within the +* Polygon's coordinate frame. If this is zero or less, the +* returned Polygon will have the number of vertices specified by +* maxvert. +* maxvert +* The maximum allowed number of vertices in the returned Polygon. +* If this is less than 3, the number of vertices in the returned +* Polygon will be the minimum needed to achieve the maximum +* discrepancy specified by +* maxerr. +* frm +* Pointer to the Frame in which the polygon is defined. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Pointer to the new PointSet. + +* Notes: +* - A null Object pointer (AST__NULL) will be returned if this +* function is invoked with the AST error status set, or if it +* should fail for any reason. +*/ + +/* Local Variables: */ + AstPointSet *result; /* Returned pointer to new PointSet */ + Segment *head; /* Pointer to new polygon edge with highest error */ + Segment *seg1; /* Pointer to new polygon edge */ + Segment *seg2; /* Pointer to new polygon edge */ + Segment *seg3; /* Pointer to new polygon edge */ + double **ptr; /* Pointer to arrays of axis values */ + double *x; /* Pointer to array of X values for old Polygon */ + double *xnew; /* Pointer to array of X values for new Polygon */ + double *y; /* Pointer to array of Y values for old Polygon */ + double *ynew; /* Pointer to array of Y values for new Polygon */ + double x1; /* Lowest X value at any vertex */ + double x2; /* Highest X value at any vertex */ + double y1; /* Lowest Y value at any vertex */ + double y2; /* Highest Y value at any vertex */ + int *newpoly; /* Holds indices of retained input vertices */ + int i1; /* Index of first vertex added to output polygon */ + int i1x; /* Index of vertex with lowest X */ + int i1y; /* Index of vertex with lowest Y */ + int i2; /* Index of second vertex added to output polygon */ + int i2x; /* Index of vertex with highest X */ + int i2y; /* Index of vertex with highest Y */ + int i3; /* Index of third vertex added to output polygon */ + int iadd; /* Normalised vertex index */ + int iat; /* Index at which to store new vertex index */ + int newlen; /* Number of vertices currently in new Polygon */ + int nv; /* Number of vertices in old Polygon */ + +/* Initialise. */ + result = NULL; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* Get the number of vertices in the supplied polygon. */ + nv = astGetNpoint( pset ); + +/* If the maximum error allowed is zero, and the maximum number of + vertices is equal to or greater than the number in the supplied + polygon, just return a deep copy of the supplied PointSet. */ + if( maxerr <= 0.0 && ( maxvert < 3 || maxvert >= nv ) ) { + result = astCopy( pset ); + +/* Otherwise... */ + } else { + +/* Get pointers to the X and Y arrays holding the vertex coordinates in + the supplied polygon. */ + ptr = astGetPoints( pset ); + x = ptr[ 0 ]; + y = ptr[ 1 ]; + +/* Allocate memory for an array to hold the original indices of the vertices + to be used to create the returned Polygon. This array is expanded as + needed. */ + newpoly = astMalloc( 10*sizeof( int ) ); + +/* Check the pointers can be used safely. */ + if( astOK ) { + +/* We first need to decide on three widely spaced vertices which form a + reasonable triangular approximation to the whole polygon. First find + the vertices with the highest and lowest Y values, and the highest and + lowest X values. */ + x1 = DBL_MAX; + x2 = -DBL_MAX; + y1 = DBL_MAX; + y2 = -DBL_MAX; + + i1y = i1x = 0; + i2y = i2x = nv/2; + + for( i3 = 0; i3 < nv; i3++ ) { + if( y[ i3 ] < y1 ) { + y1 = y[ i3 ]; + i1y = i3; + } else if( y[ i3 ] > y2 ) { + y2 = y[ i3 ]; + i2y = i3; + } + + if( x[ i3 ] < x1 ) { + x1 = x[ i3 ]; + i1x = i3; + } else if( x[ i3 ] > x2 ) { + x2 = x[ i3 ]; + i2x = i3; + } + } + +/* Use the axis which spans the greater range. */ + if( y2 - y1 > x2 - x1 ) { + i1 = i1y; + i2 = i2y; + } else { + i1 = i1x; + i2 = i2x; + } + +/* The index with vertex i1 is definitely going to be one of our three + vertices. We are going to use the line from i1 to i2 to choose the two + other vertices to use. Create a structure describing the segment of the + Polygon from the lowest value on the selected axis (X or Y) to the + highest value. As always, the polygons is traversed in an anti-clockwise + direction. */ + seg1 = NewSegment( NULL, i1, i2, nv, status ); + +/* Find the vertex within this segment which is furthest away from the + line on the right hand side (as moving from vertex i1 to vertex i2). */ + FindMax( seg1, frm, x, y, nv, 0, status ); + +/* Likewise, create a structure describing the remained of the Polygon + (i.e. the segment from the highest value on the selected axis to the + lowest value). Then find the vertex within this segment which is + furthest away from the line on the right hand side. */ + seg2 = NewSegment( NULL, i2, i1, nv, status ); + FindMax( seg2, frm, x, y, nv, 0, status ); + +/* Select the segment for which the found vertex is furthest from the + line. */ + if( seg2->error > seg1->error ) { + +/* If the second segment, we will use the vertex that is farthest from + the line as one of our threee vertices. To ensure that movement from + vertex i1 to i2 to i3 is anti-clockwise, we must use this new vertex + as vertex i3, not i2. */ + i3 = seg2->imax; + +/* Create a description of the polygon segment from vertex i1 to i3, and + find the vertex which is furthest to the right of the line joining the + two vertices. We use this as the middle vertex (i2). */ + seg1 = NewSegment( seg1, i1, i3, nv, status ); + FindMax( seg1, frm, x, y, nv, 0, status ); + i2 = seg1->imax; + +/* Do the same if we are choosing the other segment, ordering the + vertices to retain anti-clockwise movement from i1 to i2 to i3. */ + } else { + i2 = seg1->imax; + seg1 = NewSegment( seg1, i2, i1, nv, status ); + FindMax( seg1, frm, x, y, nv, 0, status ); + i3 = seg1->imax; + } + +/* Ensure the vertex indices are in the first cycle. */ + if( i2 >= nv ) i2 -= nv; + if( i3 >= nv ) i3 -= nv; + +/* Create Segment structures to describe each of these three edges. */ + seg1 = NewSegment( seg1, i1, i2, nv, status ); + seg2 = NewSegment( seg2, i2, i3, nv, status ); + seg3 = NewSegment( NULL, i3, i1, nv, status ); + +/* Record these 3 vertices in an array holding the original indices of + the vertices to be used to create the returned Polygon. */ + newpoly[ 0 ] = i1; + newpoly[ 1 ] = i2; + newpoly[ 2 ] = i3; + +/* Indicate the new polygon currently has 3 vertices. */ + newlen = 3; + +/* Search the old vertices between the start and end of segment 3, looking + for the vertex which lies furthest from the line of segment 3. The + residual between this point and the line is stored in the Segment + structure, as is the index of the vertex at which this maximum residual + occurred. */ + FindMax( seg3, frm, x, y, nv, 1, status ); + +/* The "head" variable points to the head of a double linked list of + Segment structures. This list is ordered by residual, so that the + Segment with the maximum residual is at the head, and the Segment + with the minimum residual is at the tail. Initially "seg3" is at the + head. */ + head = seg3; + +/* Search the old vertices between the start and end of segment 1, looking + for the vertex which lies furthest from the line of segment 1. The + residual between this point and the line is stored in the Segment + structure, as is the index of the vertex at which this maximum residual + occurred. */ + FindMax( seg1, frm, x, y, nv, 1, status ); + +/* Insert segment 1 into the linked list of Segments, at a position that + maintains the ordering of the segments by error. Thus the head of the + list will still have the max error. */ + head = AddToChain( head, seg1, status ); + +/* Do the same for segment 2. */ + FindMax( seg2, frm, x, y, nv, 1, status ); + head = AddToChain( head, seg2, status ); + +/* If the maximum allowed number of vertices in the output Polygon is + less than 3, allow any number of vertices up to the number in the + input Polygon (termination will then be determined just by "maxerr"). */ + if( maxvert < 3 ) maxvert = nv; + +/* Loop round adding an extra vertex to the returned Polygon until the + maximum residual between the new and old polygons is no more than + "maxerr". Abort early if the specified maximum number of vertices is + reached. */ + while( head->error > maxerr && newlen < maxvert ) { + +/* The segment at the head of the list has the max error (that is, it is + the segment that departs most from the supplied Polygon). To make the + new polygon a better fit to the old polygon, we add the vertex that is + furthest away from this segment to the new polygon. Remember that a + polygon is cyclic so if the vertex has an index that is greater than the + number of vertices in the old polygon, reduce the index by the number + of vertices in the old polygon. */ + iadd = head->imax; + if( iadd >= nv ) iadd -= nv; + iat = newlen++; + newpoly = astGrow( newpoly, newlen, sizeof( int ) ); + if( !astOK ) break; + newpoly[ iat ] = iadd; + +/* We now split the segment that had the highest error into two segments. + The split occurs at the vertex that had the highest error. */ + seg1 = NewSegment( NULL, head->imax, head->i2, nv, status ); + seg2 = head; + seg2->i2 = head->imax; + +/* We do not know where these two new segments should be in the ordered + linked list, so remove them from the list. */ + head = RemoveFromChain( head, seg1, status ); + head = RemoveFromChain( head, seg2, status ); + +/* Find the vertex that deviates most from the first of these two new + segments, and then add the segment into the list of vertices, using + the maximum deviation to determine the position of the segment within + the list. */ + FindMax( seg1, frm, x, y, nv, 1, status ); + head = AddToChain( head, seg1, status ); + +/* Do the same for the second new segment. */ + FindMax( seg2, frm, x, y, nv, 1, status ); + head = AddToChain( head, seg2, status ); + } + +/* Now we have reached the required accuracy, free resources. */ + while( head ) { + seg1 = head; + head = head->next; + seg1 = astFree( seg1 ); + } + +/* If no vertices have been left out, return a deep copy of the supplied + PointSet. */ + if( newlen == nv ) { + result = astCopy( pset ); + +/* Otherwise, sort the indices of the vertices to be retained so that they + are in the same order as they were in the supplied Polygon. */ + } else if( astOK ){ + qsort( newpoly, newlen, sizeof( int ), IntCmp ); + +/* Create a new PointSet and get pointers to its axis values. */ + result = astPointSet( newlen, 2, " ", status ); + ptr = astGetPoints( result ); + xnew = ptr[ 0 ]; + ynew = ptr[ 1 ]; + +/* Copy the axis values for the retained vertices from the old to the new + PointSet. */ + if( astOK ) { + for( iat = 0; iat < newlen; iat++ ) { + *(xnew++) = x[ newpoly[ iat ] ]; + *(ynew++) = y[ newpoly[ iat ] ]; + } + } + } + } + +/* Free resources. */ + newpoly = astFree( newpoly ); + } + +/* If an error occurred, annul the returned PointSet. */ + if ( !astOK ) result = astAnnul( result ); + +/* Return the result. */ + return result; +} + +static void EnsureInside( AstPolygon *this, int *status ){ +/* +* Name: +* EnsureInside + +* Purpose: +* Ensure the unnegated Polygon represents the inside of the polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void EnsureInside( AstPolygon *this, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* Reversing the order of the vertices of a Polygon is like negating +* the Polygon. But the parent Region class assumes that an unnegated +* region bounded by closed curves (e.g. boxes, circles, ellipses, etc) +* is bounded. So we need to have a way to ensure that a Polygon also +* follows this convention. So this function reverses the order of the +* vertices in the Polygon, if necessary, to ensure that the unnegated +* Polygon is bounded. + +* Parameters: +* this +* The Polygon. +* status +* Pointer to the inherited status variable. + +*/ + +/* Local Variables: */ + AstRegion *this_region; + double **ptr; + double *p; + double *q; + double tmp; + int bounded; + int i; + int j; + int jmid; + int negated; + int np; + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Is the unnegated Polygon unbounded? If so, we need to reverse the + vertices. */ + bounded = astGetBounded( this ); + negated = astGetNegated( this ); + if( ( bounded && negated ) || ( !bounded && !negated ) ) { + this_region = (AstRegion *) this; + +/* Get a pointer to the arrays holding the coordinates at the Polygon + vertices. */ + ptr = astGetPoints( this_region->points ); + +/* Get the number of vertices. */ + np = astGetNpoint( this_region->points ); + +/* Store the index of the last vertex to swap. For odd "np" the central + vertex does not need to be swapped. */ + jmid = np/2; + +/* Loop round the two axes spanned by the Polygon. */ + for( i = 0; i < 2; i++ ) { + +/* Get pointers to the first pair of axis values to be swapped - i.e. the + first and last axis values. */ + p = ptr[ i ]; + q = p + np - 1; + +/* Loop round all pairs of axis values. */ + for( j = 0; j < jmid; j++ ) { + +/* Swap the pair. */ + tmp = *p; + *(p++) = *q; + *(q--) = tmp; + } + } + +/* Invert the value of the "Negated" attribute to cancel out the effect + of the above vertex reversal. */ + astNegate( this ); + +/* Indicate the cached information in the Polygon structure is stale. */ + this->stale = 1; + } +} + +/* +* Name: +* FindBoxEdge + +* Purpose: +* Find an edge of the bounding box containing the selected pixels. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void FindBoxEdge<Oper><X>( <Xtype> value, const <Xtype> array[], +* int xdim, int ydim, int axis, int low, +* int *val, int *valmax, int *valmin, +* int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function search for an edge of the bounding box containing the +* selected pixels in the supplied array. + +* Parameters: +* value +* A data value that specifies the pixels to be selected. +* array +* Pointer to a 2-dimensional array containing the data to be +* processed. The numerical type of this array should match the 1- +* or 2-character type code appended to the function name. +* xdim +* The number of pixels along each row of the array. +* ydim +* The number of rows in the array. +* axis +* The index (0 or 1) of the pixel axis perpendicular to the edge of the +* bounding box being found. +* low +* If non-zero, the lower edge of the bounding box on the axis +* specified by "axis" is found and returned. Otherwise, the higher +* edge of the bounding box on the axis specified by "axis" is +* found and returned. +* val +* Address of an int in which to return the value on axis "axis" of +* the higher or lower (as specified by "low") edge of the bounding +* box. +* valmax +* Address of an int in which to return the highest value on axis +* "1-axis" of the selected pixels on the returned edge. +* valmin +* Address of an int in which to return the lowest value on axis +* "1-axis" of the selected pixels on the returned edge. +* status +* Pointer to the inherited status variable. + +* Notes; +* - Zero is returned for "*val" if no good values are found, or if +* an error occurs. + +*/ + +/* Define a macro to implement the function for a specific data + type and operation. */ +#define MAKE_FINDBOXEDGE(X,Xtype,Oper,OperI) \ +static void FindBoxEdge##Oper##X( Xtype value, const Xtype array[], int xdim, \ + int ydim, int axis, int low, int *val, \ + int *valmax, int *valmin, int *status ) { \ +\ +/* Local Variables: */ \ + int astep; \ + int bstep; \ + int a0; \ + int a1; \ + int b0; \ + int b1; \ + int inc; \ + int a; \ + int b; \ + const Xtype *pc; \ +\ +/* Initialise. */ \ + *val = 0; \ + *valmin = 0; \ + *valmax = 0; \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return; \ +\ +/* If we are finding an edge that is parallel to the X axis... */ \ + if( axis ) { \ +\ +/* Get the vector step between adjacent pixels on the selected axis, and \ + on the other axis. */ \ + astep = xdim; \ + bstep = 1; \ +\ +/* Get the first and last value to check on the selected axis, and the \ + increment between checks. */ \ + if( low ) { \ + a0 = 1; \ + a1 = ydim; \ + inc = 1; \ + } else { \ + a0 = ydim; \ + a1 = 1; \ + inc = -1; \ + } \ +\ +/* The first and last value to check on the other axis. */ \ + b0 = 1; \ + b1 = xdim; \ +\ +/* Do the same if we are finding an edge that is parallel to the Y axis. */ \ + } else { \ + astep = 1; \ + bstep = xdim; \ +\ + if( low ) { \ + a0 = 1; \ + a1 = xdim; \ + inc = 1; \ + } else { \ + a0 = xdim; \ + a1 = 1; \ + inc = -1; \ + } \ +\ + b0 = 1; \ + b1 = ydim; \ + } \ +\ +/* Loop round the axis values. */ \ + a = a0; \ + while( 1 ) { \ +\ +/* Get a pointer to the first value to be checked at this axis value. */ \ + pc = array + (a - 1)*astep + (b0 - 1)*bstep; \ +\ +/* Scan the other axis to find the first and last selected pixel. */ \ + for( b = b0; b <= b1; b++ ) { \ + if( ISVALID(*pc,OperI,value) ) { \ + if( *valmin == 0 ) *valmin = b; \ + *valmax = b; \ + } \ + pc += bstep; \ + } \ +\ +/* If any selected pixels were found, store the axis value and exit. */ \ + if( *valmax ) { \ + *val = a; \ + break; \ + } \ +\ +/* Move on to the next axis value. */ \ + if( a != a1 ) { \ + a += inc; \ + } else { \ + break; \ + } \ +\ + } \ +} + +/* Define a macro that uses the above macro to to create implementations + of FindBoxEdge for all operations. */ +#define MAKEALL_FINDBOXEDGE(X,Xtype) \ +MAKE_FINDBOXEDGE(X,Xtype,LT,AST__LT) \ +MAKE_FINDBOXEDGE(X,Xtype,LE,AST__LE) \ +MAKE_FINDBOXEDGE(X,Xtype,EQ,AST__EQ) \ +MAKE_FINDBOXEDGE(X,Xtype,NE,AST__NE) \ +MAKE_FINDBOXEDGE(X,Xtype,GE,AST__GE) \ +MAKE_FINDBOXEDGE(X,Xtype,GT,AST__GT) + +/* Expand the above macro to generate a function for each required + data type and operation. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKEALL_FINDBOXEDGE(LD,long double) +#endif +MAKEALL_FINDBOXEDGE(D,double) +MAKEALL_FINDBOXEDGE(L,long int) +MAKEALL_FINDBOXEDGE(UL,unsigned long int) +MAKEALL_FINDBOXEDGE(I,int) +MAKEALL_FINDBOXEDGE(UI,unsigned int) +MAKEALL_FINDBOXEDGE(S,short int) +MAKEALL_FINDBOXEDGE(US,unsigned short int) +MAKEALL_FINDBOXEDGE(B,signed char) +MAKEALL_FINDBOXEDGE(UB,unsigned char) +MAKEALL_FINDBOXEDGE(F,float) + +/* Undefine the macros. */ +#undef MAKE_FINDBOXEDGE +#undef MAKEALL_FINDBOXEDGE + +/* +* Name: +* FindInsidePoint + +* Purpose: +* Find a point that is inside the required outline. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void FindInsidePoint<Oper><X>( <Xtype> value, const <Xtype> array[], +* const int lbnd[ 2 ], const int ubnd[ 2 ], +* int *inx, int *iny, int *iv, +* int *status ); + +* Class Membership: +* Polygon member function + +* Description: +* The central pixel in the array is checked to see if its value meets +* the requirements implied by <Oper> and "value". If so, its pixel +* indices and vector index are returned> if not, a spiral search is +* made until such a pixel value is found. + +* Parameters: +* value +* The data value defining valid pixels. +* array +* The data array. +* lbnd +* The lower pixel index bounds of the array. +* ubnd +* The upper pixel index bounds of the array. +* inx +* Pointer to an int in which to return the X pixel index of the +* first point that meets the requirements implied by <oper> and +* "value". +* iny +* Pointer to an int in which to return the Y pixel index of the +* first point that meets the requirements implied by <oper> and +* "value". +* iv +* Pointer to an int in which to return the vector index of the +* first point that meets the requirements implied by <oper> and +* "value". +* status +* Pointer to the inherited status variable. + +* Notes: +* - <Oper> must be one of LT, LE, EQ, NE, GE, GT. + + +*/ + +/* Define a macro to implement the function for a specific data + type and operation. */ +#define MAKE_FINDINSIDEPOINT(X,Xtype,Oper,OperI) \ +static void FindInsidePoint##Oper##X( Xtype value, const Xtype array[], \ + const int lbnd[ 2 ], const int ubnd[ 2 ], \ + int *inx, int *iny, int *iv, \ + int *status ){ \ +\ +/* Local Variables: */ \ + const Xtype *pv; /* Pointer to next data value to test */ \ + const char *text; /* Pointer to text describing oper */ \ + int cy; /* Central row index */ \ + int iskin; /* Index of spiral layer being searched */ \ + int nskin; /* Number of spiral layers to search */ \ + int nx; /* Pixel per row */ \ + int tmp; /* Temporary storage */ \ + int xhi; /* High X pixel index bound of current skin */ \ + int xlo; /* Low X pixel index bound of current skin */ \ + int yhi; /* High X pixel index bound of current skin */ \ + int ylo; /* Low X pixel index bound of current skin */ \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return; \ +\ +/* Find number of pixels in one row of the array. */ \ + nx = ( ubnd[ 0 ] - lbnd[ 0 ] + 1 ); \ +\ +/* Find the pixel indices of the central pixel */ \ + *inx = ( ubnd[ 0 ] + lbnd[ 0 ] )/2; \ + *iny = ( ubnd[ 1 ] + lbnd[ 1 ] )/2; \ +\ +/* Initialise the vector index and pointer to refer to the central pixel. */ \ + *iv = ( *inx - lbnd[ 0 ] ) + nx*( *iny - lbnd[ 1 ] ) ; \ + pv = array + (*iv); \ +\ +/* Test the pixel value, returning if it is valid. This \ + relies on the compiler optimisation to remove the "if" statements \ + for all but the operation appropriate to the function being defined. */ \ + if( OperI == AST__LT ) { \ + if( *pv < value ) return; \ +\ + } else if( OperI == AST__LE ) { \ + if( *pv <= value ) return; \ +\ + } else if( OperI == AST__EQ ) { \ + if( *pv == value ) return; \ +\ + } else if( OperI == AST__NE ) { \ + if( *pv != value ) return; \ +\ + } else if( OperI == AST__GE ) { \ + if( *pv >= value ) return; \ +\ + } else { \ + if( *pv > value ) return; \ + } \ +\ +/* The central pixel is invalid if we arrive here. So we need to do a \ + spiral search out from the centre looking for a valid pixel. Record \ + the central row index (this is the row at which we jump to the next \ + outer skin when doing the spiral search below). */ \ + cy = *iny; \ +\ +/* Find how many skins can be searched as part of the spiral search \ + before the edge of the array is encountered. */ \ + nskin = ubnd[ 0 ] - *inx; \ + tmp = *inx - lbnd[ 0 ]; \ + if( tmp < nskin ) nskin = tmp; \ + tmp = ubnd[ 1 ] - *iny; \ + if( tmp < nskin ) nskin = tmp; \ + tmp = *iny - lbnd[ 1 ]; \ + if( tmp < nskin ) nskin = tmp; \ +\ +/* Initialise the skin box bounds to be just the central pixel. */ \ + xlo = xhi = *inx; \ + ylo = yhi = *iny; \ +\ +/* Loop round each skin looking for a valid test pixel. */ \ + for( iskin = 0; iskin < nskin; iskin++ ) { \ +\ +/* Increment the upper and lower bounds of the box forming the next \ + skin. */ \ + xhi++; \ + xlo--; \ + yhi++; \ + ylo--; \ +\ +/* Initialise things for the first pixel in the new skin by moving one \ + pixel to the right. */ \ + pv++; \ + (*iv)++; \ + (*inx)++; \ +\ +/* Move up the right hand edge of the box corresponding to the current \ + skin. We start at the middle of the right hand edge. */ \ + for( *iny = cy; *iny <= yhi; (*iny)++ ) { \ +\ +/* Test the pixel value, returning if it is valid. This relies on the \ + compiler optimisation to remove the "if" statements for all but the \ + operation appropriate to the function being defined. */ \ + if( OperI == AST__LT ) { \ + if( *pv < value ) return; \ +\ + } else if( OperI == AST__LE ) { \ + if( *pv <= value ) return; \ +\ + } else if( OperI == AST__EQ ) { \ + if( *pv == value ) return; \ +\ + } else if( OperI == AST__NE ) { \ + if( *pv != value ) return; \ +\ + } else if( OperI == AST__GE ) { \ + if( *pv >= value ) return; \ +\ + } else { \ + if( *pv > value ) return; \ + } \ +\ +/* Move up a pixel. */ \ + pv += nx; \ + *iv += nx; \ + } \ +\ +/* Move down a pixel so that *iny == yhi. */ \ + pv -= nx; \ + *iv -= nx; \ + (*iny)--; \ +\ +/* Move left along the top edge of the box corresponding to the current \ + skin. */ \ + for( *inx = xhi; *inx >= xlo; (*inx)-- ) { \ +\ +/* Test the pixel value, returning if it is valid. */ \ + if( OperI == AST__LT ) { \ + if( *pv < value ) return; \ +\ + } else if( OperI == AST__LE ) { \ + if( *pv <= value ) return; \ +\ + } else if( OperI == AST__EQ ) { \ + if( *pv == value ) return; \ +\ + } else if( OperI == AST__NE ) { \ + if( *pv != value ) return; \ +\ + } else if( OperI == AST__GE ) { \ + if( *pv >= value ) return; \ +\ + } else { \ + if( *pv > value ) return; \ + } \ +\ +/* Move left a pixel. */ \ + pv--; \ + (*iv)--; \ + } \ +\ +/* Move right a pixel so that *inx == xlo. */ \ + pv++; \ + (*iv)++; \ + (*inx)++; \ +\ +/* Move down along the left hand edge of the box corresponding to the current \ + skin. */ \ + for( *iny = yhi; *iny >= ylo; (*iny)-- ) { \ +\ +/* Test the pixel value, returning if it is valid. */ \ + if( OperI == AST__LT ) { \ + if( *pv < value ) return; \ +\ + } else if( OperI == AST__LE ) { \ + if( *pv <= value ) return; \ +\ + } else if( OperI == AST__EQ ) { \ + if( *pv == value ) return; \ +\ + } else if( OperI == AST__NE ) { \ + if( *pv != value ) return; \ +\ + } else if( OperI == AST__GE ) { \ + if( *pv >= value ) return; \ +\ + } else { \ + if( *pv > value ) return; \ + } \ +\ +/* Move down a pixel. */ \ + pv -= nx; \ + *iv -= nx; \ + } \ +\ +/* Move up a pixel so that *iny == ylo. */ \ + pv += nx; \ + *iv += nx; \ + (*iny)++; \ +\ +/* Move right along the bottom edge of the box corresponding to the current \ + skin. */ \ + for( *inx = xlo; *inx <= xhi; (*inx)++ ) { \ +\ +/* Test the pixel value, returning if it is valid. */ \ + if( OperI == AST__LT ) { \ + if( *pv < value ) return; \ +\ + } else if( OperI == AST__LE ) { \ + if( *pv <= value ) return; \ +\ + } else if( OperI == AST__EQ ) { \ + if( *pv == value ) return; \ +\ + } else if( OperI == AST__NE ) { \ + if( *pv != value ) return; \ +\ + } else if( OperI == AST__GE ) { \ + if( *pv >= value ) return; \ +\ + } else { \ + if( *pv > value ) return; \ + } \ +\ +/* Move right a pixel. */ \ + pv++; \ + (*iv)++; \ + } \ +\ +/* Move left a pixel so that *inx == xhi. */ \ + pv--; \ + (*iv)--; \ + (*inx)--; \ +\ +/* Move up the right hand edge of the box correspionding to the current \ + skin. We stop just below the middle of the right hand edge. */ \ + for( *iny = ylo; *iny < cy; (*iny)++ ) { \ +\ +/* Test the pixel value, returning if it is valid. This relies on the \ + compiler optimisation to remove the "if" statements for all but the \ + operation appropriate to the function being defined. */ \ + if( OperI == AST__LT ) { \ + if( *pv < value ) return; \ +\ + } else if( OperI == AST__LE ) { \ + if( *pv <= value ) return; \ +\ + } else if( OperI == AST__EQ ) { \ + if( *pv == value ) return; \ +\ + } else if( OperI == AST__NE ) { \ + if( *pv != value ) return; \ +\ + } else if( OperI == AST__GE ) { \ + if( *pv >= value ) return; \ +\ + } else { \ + if( *pv > value ) return; \ + } \ +\ +/* Move up a pixel. */ \ + pv += nx; \ + *iv += nx; \ + } \ + } \ +\ +/* Report an error if no inside pooint could be found. */ \ + if( OperI == AST__LT ) { \ + text = "less than"; \ + } else if( OperI == AST__LE ) { \ + text = "less than or equal to"; \ + } else if( OperI == AST__EQ ) { \ + text = "equal to"; \ + } else if( OperI == AST__NE ) { \ + text = "not equal to"; \ + } else if( OperI == AST__GE ) { \ + text = "greater than or equal to"; \ + } else { \ + text = "greater than"; \ + } \ + astError( AST__NONIN, "astOutline"#X": Could not find a pixel value %s " \ + "%g in the supplied array.", status, text, (double) value ); \ +} + +/* Define a macro that uses the above macro to to create implementations + of FindInsidePoint for all operations. */ +#define MAKEALL_FINDINSIDEPOINT(X,Xtype) \ +MAKE_FINDINSIDEPOINT(X,Xtype,LT,AST__LT) \ +MAKE_FINDINSIDEPOINT(X,Xtype,LE,AST__LE) \ +MAKE_FINDINSIDEPOINT(X,Xtype,EQ,AST__EQ) \ +MAKE_FINDINSIDEPOINT(X,Xtype,GE,AST__GE) \ +MAKE_FINDINSIDEPOINT(X,Xtype,GT,AST__GT) \ +MAKE_FINDINSIDEPOINT(X,Xtype,NE,AST__NE) + +/* Expand the above macro to generate a function for each required + data type and operation. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKEALL_FINDINSIDEPOINT(LD,long double) +#endif +MAKEALL_FINDINSIDEPOINT(D,double) +MAKEALL_FINDINSIDEPOINT(L,long int) +MAKEALL_FINDINSIDEPOINT(UL,unsigned long int) +MAKEALL_FINDINSIDEPOINT(I,int) +MAKEALL_FINDINSIDEPOINT(UI,unsigned int) +MAKEALL_FINDINSIDEPOINT(S,short int) +MAKEALL_FINDINSIDEPOINT(US,unsigned short int) +MAKEALL_FINDINSIDEPOINT(B,signed char) +MAKEALL_FINDINSIDEPOINT(UB,unsigned char) +MAKEALL_FINDINSIDEPOINT(F,float) + +/* Undefine the macros. */ +#undef MAKE_FINDINSIDEPOINT +#undef MAKEALL_FINDINSIDEPOINT + +static void FindMax( Segment *seg, AstFrame *frm, double *x, double *y, + int nv, int abs, int *status ){ +/* +* Name: +* FindMax + +* Purpose: +* Find the maximum discrepancy between a given line segment and the +* Polygon being downsized. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void FindMax( Segment *seg, AstFrame *frm, double *x, double *y, +* int nv, int abs, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* The supplied Segment structure describes a range of vertices in +* the polygon being downsized. This function checks each of these +* vertices to find the one that lies furthest from the line joining the +* first and last vertices in the segment. The maximum error, and the +* vertex index at which this maximum error is found, is stored in the +* Segment structure. + +* Parameters: +* seg +* The structure describing the range of vertices to check. It +* corresponds to a candidate edge in the downsized polygon. +* frm +* The Frame in which the positions are defined. +* x +* Pointer to the X axis values in the original Polygon. +* y +* Pointer to the Y axis values in the original Polygon. +* nv +* Total number of vertics in the old Polygon.. +* abs +* If non-zero, then the stored maximum is the position with +* maximum absolute error. Otherwise, the stored maximum is the +* position with maximum positive error (positive errors are to the +* right when travelling from start to end of the segment). +* status +* Pointer to the inherited status variable. + +*/ + +/* Local Variables: */ + AstPointSet *pset1; /* PointSet holding vertex positions */ + AstPointSet *pset2; /* PointSet holding offset par/perp components */ + double **ptr1; /* Pointers to "pset1" data arrays */ + double **ptr2; /* Pointers to "pset2" data arrays */ + double *px; /* Pointer to next X value */ + double *py; /* Pointer to next Y value */ + double ax; /* X value at start */ + double ay; /* Y value at start */ + double ba; /* Distance between a and b */ + double bax; /* X increment from a to b */ + double bay; /* Y increment from a to b */ + double cax; /* X increment from a to c */ + double cay; /* Y increment from a to c */ + double end[ 2 ]; /* Position of starting vertex */ + double error; /* Error value for current vertex */ + double start[ 2 ]; /* Position of starting vertex */ + int i1; /* Starting index (always in first cycle) */ + int i2; /* Ending index converted to first cycle */ + int i2b; /* Upper vertex limit in first cycle */ + int i; /* Loop count */ + int n; /* Number of vertices to check */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Stuff needed for handling cyclic redundancy of vertex indices. */ + i1 = seg->i1; + i2 = seg->i2; + n = i2 - i1 - 1; + i2b = i2; + if( i2 >= nv ) { + i2 -= nv; + i2b = nv; + } + +/* If the segment has no intermediate vertices, set the segment error to + zero and return. */ + if( n < 1 ) { + seg->error = 0.0; + seg->imax = i1; + +/* For speed, we use simple plane geometry if the Polygon is defined in a + simple Frame. */ + } else if( !strcmp( astGetClass( frm ), "Frame" ) ) { + +/* Point "a" is the vertex that marks the start of the segment. Point "b" + is the vertex that marks the end of the segment. */ + ax = x[ i1 ]; + ay = y[ i1 ]; + bax = x[ i2 ] - ax; + bay = y[ i2 ] - ay; + ba = sqrt( bax*bax + bay*bay ); + +/* Initialise the largest error found so far. */ + seg->error = -1.0; + +/* Check the vertices from the start (plus one) up to the end (minus one) + or the last vertex (which ever comes first). */ + for( i = i1 + 1; i < i2b; i++ ) { + +/* Position "c" is the vertex being tested. Find the squared distance from + "c" to the line joining "a" and "b". */ + cax = x[ i ] - ax; + cay = y[ i ] - ay; + error = ( bay*cax - cay*bax )/ba; + if( abs ) error = fabs( error ); + +/* If this is the largest value found so far, record it. Note the error + here is a squared distance. */ + if( error > seg->error ) { + seg->error = error; + seg->imax = i; + } + } + +/* If the end vertex is in the next cycle, check the remaining vertex + posI would have thought a telentitions in the same way. */ + if( i2b != i2 ) { + + for( i = 0; i < i2; i++ ) { + + cax = x[ i ] - ax; + cay = y[ i ] - ay; + error = ( bay*cax - cay*bax )/ba; + if( abs ) error = fabs( error ); + + if( error > seg->error ) { + seg->error = error; + seg->imax = i + i2b; + } + + } + } + +/* If the polygon is not defined in a simple Frame, we use the overloaded + Frame methods to do the geometry. */ + } else { + +/* Create a PointSet to hold the positions of the vertices to test. We do + not need to test the start or end vertex. */ + pset1 = astPointSet( n, 2, " ", status ); + ptr1 = astGetPoints( pset1 ); + if( astOK ) { + +/* Copy the vertex axis values form the start (plus one) up to the end + (minus one) vertex or the last vertex (which ever comes first). */ + px = ptr1[ 0 ]; + py = ptr1[ 1 ]; + + for( i = i1 + 1; i < i2b; i++ ){ + *(px++) = x[ i ]; + *(py++) = y[ i ]; + } + +/* If the end vertex is in the next cycle, copy the remaining vertex + positions into the PointSet. */ + if( i2b != i2 ) { + for( i = 0; i < i2; i++ ) { + *(px++) = x[ i ]; + *(py++) = y[ i ]; + } + } + +/* Record the start and end vertex positions. */ + start[ 0 ] = x[ i1 ]; + start[ 1 ] = y[ i1 ]; + end[ 0 ] = x[ i2 ]; + end[ 1 ] = y[ i2 ]; + +/* Resolve the vector from the start to each vertex into two components, + parallel and perpendicular to the start->end vector. */ + pset2 = astResolvePoints( frm, start, end, pset1, NULL ); + ptr2 = astGetPoints( pset2 ); + if( astOK ) { + +/* Find the vertex with largest perpendicular component. */ + seg->error = -1.0; + py = ptr2[ 1 ]; + for( i = 1; i <= n; i++ ) { + + error = *(py++); + if( abs ) error = fabs( error ); + + if( error > seg->error ) { + seg->error = error; + seg->imax = i + i1; + } + + } + } + +/* Free resources. */ + pset2 = astAnnul( pset2 ); + } + pset1 = astAnnul( pset1 ); + } +} + +static const char *GetAttrib( AstObject *this_object, const char *attrib, int *status ) { +/* +* Name: +* GetAttrib + +* Purpose: +* Get the value of a specified attribute for a Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* const char *GetAttrib( AstObject *this, const char *attrib, int *status ) + +* Class Membership: +* Polygon member function (over-rides the protected astGetAttrib +* method inherited from the Region class). + +* Description: +* This function returns a pointer to the value of a specified +* attribute for a Polygon, formatted as a character string. + +* Parameters: +* this +* Pointer to the Polygon. +* attrib +* Pointer to a null-terminated string containing the name of +* the attribute whose value is required. This name should be in +* lower case, with all white space removed. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* - Pointer to a null-terminated string containing the attribute +* value. + +* Notes: +* - The returned string pointer may point at memory allocated +* within the Polygon, or at static memory. The contents of the +* string may be over-written or the pointer may become invalid +* following a further invocation of the same function or any +* modification of the Polygon. A copy of the string should +* therefore be made if necessary. +* - A NULL pointer will be returned if this function is invoked +* with the global error status set, or if it should fail for any +* reason. +*/ + +/* Local Variables: */ + astDECLARE_GLOBALS /* Pointer to thread-specific global data */ + AstPolygon *this; /* Pointer to the Polygon structure */ + const char *result; /* Pointer value to return */ + int ival; /* Integer attribute value */ + +/* Initialise. */ + result = NULL; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* Get a pointer to the thread specific global data structure. */ + astGET_GLOBALS(this_object); + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) this_object; + +/* Compare "attrib" with each recognised attribute name in turn, + obtaining the value of the required attribute. If necessary, write + the value into "getattrib_buff" as a null-terminated string in an appropriate + format. Set "result" to point at the result string. */ + +/* SimpVertices. */ +/* ------------- */ + if ( !strcmp( attrib, "simpvertices" ) ) { + ival = astGetSimpVertices( this ); + if ( astOK ) { + (void) sprintf( getattrib_buff, "%d", ival ); + result = getattrib_buff; + } + +/* If the attribute name was not recognised, pass it on to the parent + method for further interpretation. */ + } else { + result = (*parent_getattrib)( this_object, attrib, status ); + } + +/* Return the result. */ + return result; + +} + +static int GetBounded( AstRegion *this, int *status ) { +/* +* Name: +* GetBounded + +* Purpose: +* Is the Region bounded? + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* int GetBounded( AstRegion *this, int *status ) + +* Class Membership: +* Polygon method (over-rides the astGetBounded method inherited from +* the Region class). + +* Description: +* This function returns a flag indicating if the Region is bounded. +* The implementation provided by the base Region class is suitable +* for Region sub-classes representing the inside of a single closed +* curve (e.g. Circle, Interval, Box, etc). Other sub-classes (such as +* CmpRegion, PointList, etc ) may need to provide their own +* implementations. + +* Parameters: +* this +* Pointer to the Region. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Non-zero if the Region is bounded. Zero otherwise. + +*/ + +/* Local Variables: */ + int neg; /* Has the Polygon been negated? */ + int result; /* Returned result */ + +/* Initialise */ + result = 0; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* Ensure cached information is available. */ + Cache( (AstPolygon *) this, status ); + +/* See if the Polygon has been negated. */ + neg = astGetNegated( this ); + +/* If the polygon vertices are stored in anti-clockwise order, then the + polygon is bounded if it has not been negated. */ + if( ( (AstPolygon *) this)->acw ) { + result = (! neg ); + +/* If the polygon vertices are stored in clockwise order, then the + polygon is bounded if it has been negated. */ + } else { + result = neg; + } + +/* Return the result. */ + return result; +} + +void astInitPolygonVtab_( AstPolygonVtab *vtab, const char *name, int *status ) { +/* +*+ +* Name: +* astInitPolygonVtab + +* Purpose: +* Initialise a virtual function table for a Polygon. + +* Type: +* Protected function. + +* Synopsis: +* #include "polygon.h" +* void astInitPolygonVtab( AstPolygonVtab *vtab, const char *name ) + +* Class Membership: +* Polygon vtab initialiser. + +* Description: +* This function initialises the component of a virtual function +* table which is used by the Polygon class. + +* Parameters: +* vtab +* Pointer to the virtual function table. The components used by +* all ancestral classes will be initialised if they have not already +* been initialised. +* name +* Pointer to a constant null-terminated character string which contains +* the name of the class to which the virtual function table belongs (it +* is this pointer value that will subsequently be returned by the Object +* astClass function). +*- +*/ + +/* Local Variables: */ + astDECLARE_GLOBALS /* Pointer to thread-specific global data */ + AstMappingVtab *mapping; /* Pointer to Mapping component of Vtab */ + AstRegionVtab *region; /* Pointer to Region component of Vtab */ + AstObjectVtab *object; /* Pointer to Object component of Vtab */ + +/* Check the local error status. */ + if ( !astOK ) return; + +/* Get a pointer to the thread specific global data structure. */ + astGET_GLOBALS(NULL); + +/* Initialize the component of the virtual function table used by the + parent class. */ + astInitRegionVtab( (AstRegionVtab *) vtab, name ); + +/* Store a unique "magic" value in the virtual function table. This + will be used (by astIsAPolygon) to determine if an object belongs + to this class. We can conveniently use the address of the (static) + class_check variable to generate this unique value. */ + vtab->id.check = &class_check; + vtab->id.parent = &(((AstRegionVtab *) vtab)->id); + +/* Initialise member function pointers. */ +/* ------------------------------------ */ +/* Store pointers to the member functions (implemented here) that provide + virtual methods for this class. */ + vtab->Downsize = Downsize; + +/* Save the inherited pointers to methods that will be extended, and + replace them with pointers to the new member functions. */ + object = (AstObjectVtab *) vtab; + mapping = (AstMappingVtab *) vtab; + region = (AstRegionVtab *) vtab; + + parent_transform = mapping->Transform; + mapping->Transform = Transform; + + parent_simplify = mapping->Simplify; + mapping->Simplify = Simplify; + + parent_setregfs = region->SetRegFS; + region->SetRegFS = SetRegFS; + + parent_resetcache = region->ResetCache; + region->ResetCache = ResetCache; + + parent_clearattrib = object->ClearAttrib; + object->ClearAttrib = ClearAttrib; + parent_getattrib = object->GetAttrib; + object->GetAttrib = GetAttrib; + parent_setattrib = object->SetAttrib; + object->SetAttrib = SetAttrib; + parent_testattrib = object->TestAttrib; + object->TestAttrib = TestAttrib; + + region->RegPins = RegPins; + region->RegBaseMesh = RegBaseMesh; + region->RegBaseBox = RegBaseBox; + region->RegTrace = RegTrace; + region->GetBounded = GetBounded; + + vtab->ClearSimpVertices = ClearSimpVertices; + vtab->GetSimpVertices = GetSimpVertices; + vtab->SetSimpVertices = SetSimpVertices; + vtab->TestSimpVertices = TestSimpVertices; + +/* Store replacement pointers for methods which will be over-ridden by + new member functions implemented here. */ + +/* Declare the copy constructor, destructor and class dump + functions. */ + astSetDump( vtab, Dump, "Polygon", "Polygonal region" ); + astSetDelete( vtab, Delete ); + astSetCopy( vtab, Copy ); + +/* If we have just initialised the vtab for the current class, indicate + that the vtab is now initialised, and store a pointer to the class + identifier in the base "object" level of the vtab. */ + if( vtab == &class_vtab ) { + class_init = 1; + astSetVtabClassIdentifier( vtab, &(vtab->id) ); + } +} + +static int IntCmp( const void *a, const void *b ){ +/* +* Name: +* IntCmp + +* Purpose: +* An integer comparison function for the "qsort" function. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* int IntCmp( const void *a, const void *b ) + +* Class Membership: +* Polygon member function + +* Description: +* See the docs for "qsort". + +* Parameters: +* a +* Pointer to the first int +* b +* Pointer to the second int + +* Returnd Value: +* Positive, negative or zero, depending on whether a is larger than, +* equal to, or less than b. + +*/ + + return *((int*)a) - *((int*)b); +} + +static Segment *NewSegment( Segment *seg, int i1, int i2, int nvert, + int *status ){ +/* +* Name: +* NewSegment + +* Purpose: +* Initialise a structure describing a segment of the new Polygon +* created by astDownsize. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* Segment *NewSegment( Segment *seg, int i1, int i2, int nvert, +* int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function initialises the contents of a structure describing +* the specified range of vertices within a Polygon. The cyclic nature +* of vertex indices is taken into account. +* +* If no structure is supplied, memory is allocated to hold a new +* structure. + +* Parameters: +* seg +* Pointer to a structure to initialise, or NULL if a new structure +* is to be allocated. +* i1 +* The index of a vertex within the old Polygon (supplied to +* astDownsize) that marks the start of the new line segment in +* the downsized polygon. +* i2 +* The index of a vertex within the old Polygon (supplied to +* astDownsize) that marks the end of the new line segment in +* the downsized polygon. +* nvert +* Total number of vertics in the old Polygon.. +* status +* Pointer to the inherited status variable. + +* Returnd Value: +* Pointer to the initialised Segment structure. It should be freed using +* astFree when no longer needed. + +*/ + +/* Local Variables: */ + Segment *result; + +/* Check the global error status. */ + if ( !astOK ) return NULL; + +/* Get a pointer to the structure to be initialised, allocating memory + for a new structure if none was supplied. */ + result = seg ? seg : astMalloc( sizeof( Segment ) ); + +/* Check the pointer can be used safely. */ + if( result ) { + +/* If the supplied ending index is less than the starting index, the + ending index must have gone all the way round the polygon and started + round again. Increase the ending index by the number of vertices to + put it in the same cycle as the starting index. */ + if( i2 < i1 ) i2 += nvert; + +/* If the supplied starting index is within the first cycle (i.e. zero -> + nvert-1 ), use the indices as they are (which may mean that the ending + index is greater than nvert, but this is handled correctly by other + functions). */ + if( i1 < nvert ) { + result->i1 = i1; + result->i2 = i2; + +/* If the supplied starting index is within the second cycle (i.e. nvert + or greater) the ending index will be even greater, so we can reduce + both by "nvert" to put them both in the first cycle. The goal is that + the starting index should always be in the first cycle, but the ending + index may possibly be in the second cycle. */ + } else { + result->i1 = i1 - nvert; + result->i2 = i2 - nvert; + } + +/* Nullify the links to other Segments */ + result->next = NULL; + result->prev = NULL; + } + +/* Return the pointer to the new Segment structure. */ + return result; +} + +/* +*++ +* Name: +c astOutline<X> +f AST_OUTLINE<X> + +* Purpose: +* Create a new Polygon outling values in a 2D data grid. + +* Type: +* Public function. + +* Synopsis: +c #include "polygon.h" +c AstPolygon *astOutline<X>( <Xtype> value, int oper, const <Xtype> array[], +c const int lbnd[2], const int ubnd[2], double maxerr, +c int maxvert, const int inside[2], int starpix ) +f RESULT = AST_OUTLINE<X>( VALUE, OPER, ARRAY, LBND, UBND, MAXERR, +f MAXVERT, INSIDE, STARPIX, STATUS ) + +* Class Membership: +* Polygon method. + +* Description: +* This is a set of functions that create a Polygon enclosing a single +* contiguous set of pixels that have a specified value within a gridded +* 2-dimensional data array (e.g. an image). +* +* A basic 2-dimensional Frame is used to represent the pixel coordinate +* system in the returned Polygon. The Domain attribute is set to +* "PIXEL", the Title attribute is set to "Pixel coordinates", and the +* Unit attribute for each axis is set to "pixel". All other +* attributes are left unset. The nature of the pixel coordinate system +* is determined by parameter +c "starpix". +f STARPIX. +* +* The +c "maxerr" and "maxvert" +f MAXERR and MAXVERT +* parameters can be used to control how accurately the returned +* Polygon represents the required region in the data array. The +* number of vertices in the returned Polygon will be the minimum +* needed to achieve the required accuracy. +* +* You should use a function which matches the numerical type of the +* data you are processing by replacing <X> in the generic function +* name +c astOutline<X> +f AST_OUTLINE<X> +c by an appropriate 1- or 2-character type code. For example, if you +* are procesing data with type +c "float", you should use the function astOutlineF +f REAL, you should use the function AST_OUTLINER +* (see the "Data Type Codes" section below for the codes appropriate to +* other numerical types). + +* Parameters: +c value +f VALUE = <Xtype> (Given) +* A data value that specifies the pixels to be outlined. +c oper +f OPER = INTEGER (Given) +* Indicates how the +c "value" +f VALUE +* parameter is used to select the outlined pixels. It can +* have any of the following values: +c - AST__LT: outline pixels with value less than "value". +c - AST__LE: outline pixels with value less than or equal to "value". +c - AST__EQ: outline pixels with value equal to "value". +c - AST__NE: outline pixels with value not equal to "value". +c - AST__GE: outline pixels with value greater than or equal to "value". +c - AST__GT: outline pixels with value greater than "value". +f - AST__LT: outline pixels with value less than VALUE. +f - AST__LE: outline pixels with value less than or equal to VALUE. +f - AST__EQ: outline pixels with value equal to VALUE. +f - AST__NE: outline pixels with value not equal to VALUE. +f - AST__GE: outline pixels with value greater than or equal to VALUE. +f - AST__GT: outline pixels with value greater than VALUE. +c array +f ARRAY( * ) = <Xtype> (Given) +c Pointer to a +f A +* 2-dimensional array containing the data to be processed. The +* numerical type of this array should match the 1- or +* 2-character type code appended to the function name (e.g. if +c you are using astOutlineF, the type of each array element +c should be "float"). +f you are using AST_OUTLINER, the type of each array element +f should be REAL). +* +* The storage order of data within this array should be such +* that the index of the first grid dimension varies most +* rapidly and that of the second dimension least rapidly +c (i.e. Fortran array indexing is used). +f (i.e. normal Fortran array storage order). +c lbnd +f LBND( 2 ) = INTEGER (Given) +c Pointer to an array of two integers +f An array +* containing the pixel index of the first pixel in the input grid +* along each dimension. +c ubnd +f UBND( 2) = INTEGER (Given) +c Pointer to an array of two integers +f An array +* containing the pixel index of the last pixel in the input grid +* along each dimension. +* +c Note that "lbnd" and "ubnd" together define the shape +f Note that LBND and UBND together define the shape +* and size of the input pixel grid, its extent along a particular +c (j'th) dimension being ubnd[j]-lbnd[j]+1 pixels. +f (J'th) dimension being UBND(J)-LBND(J)+1 pixels. +* For FITS images, +c the lbnd values will be 1 and the ubnd +f the LBND values will be 1 and the UBND +* values will be equal to the NAXISi header values. Other +* data systems, such as the Starlink NDF system, allow an +c arbitrary pixel origin to be used (i.e. lbnd +f arbitrary pixel origin to be used (i.e. LBND +* is not necessarily 1). +* +* These bounds also define the input grid's floating point coordinate +* system, each pixel having unit extent along each dimension with +* integral coordinate values at its centre or upper corner, as selected +* by parameter +c "starpix". +f STARPIX. +c maxerr +f MAXERR = DOUBLE PRECISION (Given) +* Together with +c "maxvert", +f MAXVERT, +* this determines how accurately the returned Polygon represents +* the required region of the data array. It gives the target +* discrepancy between the returned Polygon and the accurate outline +* in the data array, expressed as a number of pixels. Insignificant +* vertices are removed from the accurate outline, one by one, until +* the number of vertices remaining in the returned Polygon equals +c "maxvert", +f MAXVERT, +* or the largest discrepancy between the accurate outline and the +* returned Polygon is greater than +c "maxerr". If "maxerr" +f MAXERR. If MAXERR +* is zero or less, its value is ignored and the returned Polygon will +* have the number of vertices specified by +c "maxvert". +f MAXVERT. +c maxvert +f MAXVERT = INTEGER (Given) +* Together with +c "maxerr", +f MAXERR, +* this determines how accurately the returned Polygon represents +* the required region of the data array. It gives the maximum +* allowed number of vertices in the returned Polygon. Insignificant +* vertices are removed from the accurate outline, one by one, until +* the number of vertices remaining in the returned Polygon equals +c "maxvert", +f MAXVERT, +* or the largest discrepancy between the accurate outline and the +* returned Polygon is greater than +c "maxerr". If "maxvert" +f MAXERR. If MAXVERT +* is less than 3, its value is ignored and the number of vertices in +* the returned Polygon will be the minimum needed to ensure that the +* discrepancy between the accurate outline and the returned +* Polygon is less than +c "maxerr". +f MAXERR. +c inside +f INSIDE( 2 ) = INTEGER (Given) +c Pointer to an array of two integers +f An array +* containing the pixel indices of a pixel known to be inside the +* required region. This is needed because the supplied data +* array may contain several disjoint areas of pixels that satisfy +* the criterion specified by +c "value" and "oper". +f VALUE and OPER. +* In such cases, the area described by the returned Polygon will +* be the one that contains the pixel specified by +c "inside". +f INSIDE. +* If the specified pixel is outside the bounds given by +c "lbnd" and "ubnd", +f LBND and UBND, +* or has a value that does not meet the criterion specified by +c "value" and "oper", +f VALUE and OPER, +* then this function will search for a suitable pixel. The search +* starts at the central pixel and proceeds in a spiral manner until +* a pixel is found that meets the specified crierion. +c starpix +f STARPIX = LOGICAL (Given) +* A flag indicating the nature of the pixel coordinate system used +* to describe the vertex positions in the returned Polygon. If +c non-zero, +f .TRUE., +* the standard Starlink definition of pixel coordinate is used in +* which a pixel with integer index I spans a range of pixel coordinate +* from (I-1) to I (i.e. pixel corners have integral pixel coordinates). +c If zero, +f If .FALSE., +* the definition of pixel coordinate used by other AST functions +c such as astResample, astMask, +f such as AST_RESAMPLE, AST_MASK, +* etc., is used. In this definition, a pixel with integer index I +* spans a range of pixel coordinate from (I-0.5) to (I+0.5) (i.e. +* pixel centres have integral pixel coordinates). +f STATUS = INTEGER (Given and Returned) +f The global status. + +* Returned Value: +c astOutline<X>() +f AST_OUTLINE<X> = INTEGER +* A pointer to the required Polygon. + +* Notes: +* - This function proceeds by first finding a very accurate polygon, +* and then removing insignificant vertices from this fine polygon +* using +c astDownsize. +f AST_DOWNSIZE. +* - The returned Polygon is the outer boundary of the contiguous set +* of pixels that includes ths specified "inside" point, and satisfy +* the specified value requirement. This set of pixels may potentially +* include "holes" where the pixel values fail to meet the specified +* value requirement. Such holes will be ignored by this function. +c - NULL +f - AST__NULL +* will be returned if this function is invoked with the global +* error status set, or if it should fail for any reason. + +* Data Type Codes: +* To select the appropriate masking function, you should +c replace <X> in the generic function name astOutline<X> with a +f replace <X> in the generic function name AST_OUTLINE<X> with a +* 1- or 2-character data type code, so as to match the numerical +* type <Xtype> of the data you are processing, as follows: +c - D: double +c - F: float +c - L: long int +c - UL: unsigned long int +c - I: int +c - UI: unsigned int +c - S: short int +c - US: unsigned short int +c - B: byte (signed char) +c - UB: unsigned byte (unsigned char) +f - D: DOUBLE PRECISION +f - R: REAL +f - I: INTEGER +f - UI: INTEGER (treated as unsigned) +f - S: INTEGER*2 (short integer) +f - US: INTEGER*2 (short integer, treated as unsigned) +f - B: BYTE (treated as signed) +f - UB: BYTE (treated as unsigned) +* +c For example, astOutlineD would be used to process "double" +c data, while astOutlineS would be used to process "short int" +c data, etc. +f For example, AST_OUTLINED would be used to process DOUBLE +f PRECISION data, while AST_OUTLINES would be used to process +f short integer data (stored in an INTEGER*2 array), etc. +f +f For compatibility with other Starlink facilities, the codes W +f and UW are provided as synonyms for S and US respectively (but +f only in the Fortran interface to AST). + +*-- +*/ +/* Define a macro to implement the function for a specific data + type. Note, this function cannot be a virtual function since the + argument list does not include a Polygon, and so no virtual function + table is available. */ +#define MAKE_OUTLINE(X,Xtype) \ +AstPolygon *astOutline##X##_( Xtype value, int oper, const Xtype array[], \ + const int lbnd[2], const int ubnd[2], double maxerr, \ + int maxvert, const int inside[2], int starpix, \ + int *status ) { \ +\ +/* Local Variables: */ \ + AstFrame *frm; /* Frame in which to define the Polygon */ \ + AstPointSet *candidate; /* Candidate polygon vertices */ \ + AstPointSet *pset; /* PointSet holding downsized polygon vertices */ \ + AstPolygon *result; /* Result value to return */ \ + const Xtype *pv; /* Pointer to next test point */ \ + Xtype v; /* Value of current pixel */ \ + double **ptr; /* Pointers to PointSet arrays */ \ + int boxsize; /* Half width of smoothign box in vertices */ \ + int inx; /* X index of inside point */ \ + int iny; /* Y index of inside point */ \ + int iv; /* Vector index of next test pixel */ \ + int ixv; /* X pixel index of next test point */ \ + int nv0; /* Number of vertices in accurate outline */ \ + int nx; /* Length of array x axis */ \ + int smooth; /* Do we need to smooth the polygon? */ \ + int stop_at_invalid; /* Indicates when to stop rightwards search */ \ + int tmp; /* Alternative boxsize */ \ + int valid; /* Does current pixel meet requirements? */ \ + static double junk[ 6 ] = {0.0, 0.0, 1.0, 1.0, 0.0, 1.0 }; /* Junk poly */ \ +\ +/* Initialise. */ \ + result = NULL; \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return result; \ +\ +/* Avoid compiler warnings. */ \ + iv = 0; \ +\ +/* If we are going to be smoothing the polygon before downsizing it, we \ + need to ensure that the full polygon is retained within TraceEdge. if \ + this is not the case, TraceEdge can remove all vertices from straight \ + lines, except for the vertices that mark the beinning and end of the \ + straight line. */ \ + smooth = ( maxerr > 0.0 || maxvert > 2 ); \ +\ +/* Store the X dimension of the array. */ \ + nx = ubnd[ 0 ] - lbnd[ 0 ] + 1; \ +\ +/* See if a valid inside point was supplied. It must be inside the bounds \ + of the array, and must have a pixel value that meets the specified \ + requirement. */ \ + inx = inside[ 0 ]; \ + iny = inside[ 1 ]; \ + valid = ( inx >= lbnd[ 0 ] && inx <= ubnd[ 0 ] && \ + iny >= lbnd[ 1 ] && iny <= ubnd[ 1 ] ); \ +\ + if( valid ) { \ + iv = ( inx - lbnd[ 0 ] ) + (iny - lbnd[ 1 ] )*nx; \ + v = array[ iv ]; \ +\ + if( oper == AST__LT ) { \ + valid = ( v < value ); \ +\ + } else if( oper == AST__LE ) { \ + valid = ( v <= value ); \ +\ + } else if( oper == AST__EQ ) { \ + valid = ( v == value ); \ +\ + } else if( oper == AST__NE ) { \ + valid = ( v != value ); \ +\ + } else if( oper == AST__GE ) { \ + valid = ( v >= value ); \ +\ + } else if( oper == AST__GT ) { \ + valid = ( v > value ); \ +\ + } else if( astOK ){ \ + astError( AST__OPRIN, "astOutline"#X": Invalid operation code " \ + "(%d) supplied (programming error).", status, oper ); \ + } \ + } \ +\ +/* If no valid inside point was supplied, find one now. */ \ + if( !valid ) { \ +\ + if( oper == AST__LT ) { \ + FindInsidePointLT##X( value, array, lbnd, ubnd, &inx, &iny, &iv, status ); \ +\ + } else if( oper == AST__LE ) { \ + FindInsidePointLE##X( value, array, lbnd, ubnd, &inx, &iny, &iv, status ); \ +\ + } else if( oper == AST__EQ ) { \ + FindInsidePointEQ##X( value, array, lbnd, ubnd, &inx, &iny, &iv, status ); \ +\ + } else if( oper == AST__NE ) { \ + FindInsidePointNE##X( value, array, lbnd, ubnd, &inx, &iny, &iv, status ); \ +\ + } else if( oper == AST__GE ) { \ + FindInsidePointGE##X( value, array, lbnd, ubnd, &inx, &iny, &iv, status ); \ +\ + } else if( oper == AST__GT ) { \ + FindInsidePointGT##X( value, array, lbnd, ubnd, &inx, &iny, &iv, status ); \ +\ + } else if( astOK ){ \ + astError( AST__OPRIN, "astOutline"#X": Invalid operation code " \ + "(%d) supplied (programming error).", status, oper ); \ + } \ + } \ +\ +/* We now need to find a point on the boundary of the region containing \ + the inside point. Starting at the inside point, move to the right \ + through the array until a pixel is found which fails to meet the value \ + requirement or the edge of the array is reached. */ \ +\ + candidate = NULL; \ + pv = array + iv; \ + ixv = inx; \ + stop_at_invalid = 1; \ +\ + while( ++ixv <= ubnd[ 0 ] ) { \ +\ +/* Get the next pixel value. */ \ + v = *(++pv); \ +\ +/* See if it meets the value requirement. */ \ + if( oper == AST__LT ) { \ + valid = ( v < value ); \ +\ + } else if( oper == AST__LE ) { \ + valid = ( v <= value ); \ +\ + } else if( oper == AST__EQ ) { \ + valid = ( v == value ); \ +\ + } else if( oper == AST__NE ) { \ + valid = ( v != value ); \ +\ + } else if( oper == AST__GE ) { \ + valid = ( v >= value ); \ +\ + } else if( oper == AST__GT ) { \ + valid = ( v > value ); \ +\ + } else if( astOK ){ \ + astError( AST__OPRIN, "astOutline"#X": Invalid operation code " \ + "(%d) supplied (programming error).", status, oper ); \ + break; \ + } \ +\ +/* If we are currently looking for the next invalid pixel, and this pixel \ + is invalid... */ \ + if( stop_at_invalid ) { \ + if( ! valid ) { \ +\ +/* The current pixel may be on the required polygon, or it may be on the \ + edge of a hole contained within the region being outlined. We would \ + like to jump over such holes so that we can continue to look for the \ + real edge of the region being outlined. In order to determine if we \ + have reached a hole, we trace the edge that passes through the current \ + pixel, forming a candidate polygon in the process. In the process, We \ + see if the inside point falls within this candidate polygon. If it does \ + then the polygon is accepted as the required polygon. Otherwise, it is \ + rejected as a mere hole, and we continue moving away from the inside \ + point, looking for a new edge. */ \ + if( oper == AST__LT ) { \ + candidate = TraceEdgeLT##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__LE ) { \ + candidate = TraceEdgeLE##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__EQ ) { \ + candidate = TraceEdgeEQ##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__NE ) { \ + candidate = TraceEdgeNE##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__GE ) { \ + candidate = TraceEdgeGE##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__GT ) { \ + candidate = TraceEdgeGT##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( astOK ){ \ + astError( AST__OPRIN, "astOutline"#X": Invalid operation code " \ + "(%d) supplied (programming error).", status, oper ); \ + } \ +\ +/* If the candidate polygon is the required polygon, break out of the \ + loop. Otherwise, indicate that we want to continue moving right, \ + across the hole, until we reach the far side of the hole (i.e. find \ + the next valid pixel). */ \ + if( candidate ) { \ + break; \ + } else { \ + stop_at_invalid = 0; \ + } \ + } \ +\ +/* If we are currently looking for the next valid pixel, and the current \ + pixel is valid... */ \ + } else if( valid ) { \ +\ +/* We have reached the far side of a hole. Continue moving right, looking \ + now for the next invalid pixel (which may be on the required polygon). */ \ + stop_at_invalid = 1; \ + } \ + } \ +\ +/* If we have not yet found the required polygon, we must have reached \ + the right hand edge of the array. So we now follow the edge of the \ + array round until we meet the boundary of the required region. */ \ + if( !candidate ) { \ + if( oper == AST__LT ) { \ + candidate = TraceEdgeLT##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__LE ) { \ + candidate = TraceEdgeLE##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__EQ ) { \ + candidate = TraceEdgeEQ##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__NE ) { \ + candidate = TraceEdgeNE##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__GE ) { \ + candidate = TraceEdgeGE##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( oper == AST__GT ) { \ + candidate = TraceEdgeGT##X( value, array, lbnd, ubnd, iv - 1, \ + ixv - 1, iny, starpix, smooth, status ); \ +\ + } else if( astOK ){ \ + astError( AST__OPRIN, "astOutline"#X": Invalid operation code " \ + "(%d) supplied (programming error).", status, oper ); \ + } \ + } \ +\ +/* If required smooth the full resolution polygon before downsizing it. */ \ + if( smooth ) { \ +\ +/* Initially, set the boxsize to be equal to the required accouracy. */ \ + if( maxerr > 0 ) { \ + boxsize = (int) maxerr; \ + } else { \ + boxsize = INT_MAX; \ + } \ +\ +/* Determine a second box size equal to the average number of vertices in \ + the accurate outline, per vertex in the returned Polygon. */ \ + nv0 = astGetNpoint( candidate ); \ + if( maxvert > 2 ) { \ + tmp = nv0/(2*maxvert); \ + } else { \ + tmp = INT_MAX; \ + } \ +\ +/* Use the minimum of the two box sizes. */ \ + if( tmp < boxsize ) boxsize = tmp; \ +\ +/* Ensure the box is sufficiently small to allow at least 10 full boxes \ + (=20 half boxes) around the polygon. */ \ + tmp = nv0/20; \ + if( tmp < boxsize ) boxsize = tmp; \ + if( boxsize == 0 ) boxsize = 1; \ +\ +/* Smooth the polygon. */ \ + SmoothPoly( candidate, boxsize, 1.0, status ); \ + } \ +\ +/* Reduce the number of vertices in the outline. */ \ + frm = astFrame( 2, "Domain=PIXEL,Unit(1)=pixel,Unit(2)=pixel," \ + "Title=Pixel coordinates", status ); \ + pset = DownsizePoly( candidate, maxerr, maxvert, frm, status ); \ +\ +/* Create a default Polygon with 3 junk vertices. */ \ + result = astPolygon( frm, 3, 3, junk, NULL, " ", status ); \ +\ +/* Change the PointSet within the Polygon to the one created above. */ \ + SetPointSet( result, pset, status ); \ +\ +/* Free resources. Note, we need to free the arrays within the candidate \ + PointSet explicitly, since they were not created as part of the \ + construction of the PointSet (see TraceEdge). */ \ + pset = astAnnul( pset ); \ + frm = astAnnul( frm ); \ + ptr = astGetPoints( candidate ); \ + if( astOK ) { \ + astFree( ptr[ 0 ] ); \ + astFree( ptr[ 1 ] ); \ + } \ + candidate = astAnnul( candidate ); \ +\ +/* If an error occurred, clear the returned result. */ \ + if ( !astOK ) result = astAnnul( result ); \ +\ +/* Return the result. */ \ + return result; \ +} + + +/* Expand the above macro to generate a function for each required + data type. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKE_OUTLINE(LD,long double) +#endif +MAKE_OUTLINE(D,double) +MAKE_OUTLINE(L,long int) +MAKE_OUTLINE(UL,unsigned long int) +MAKE_OUTLINE(I,int) +MAKE_OUTLINE(UI,unsigned int) +MAKE_OUTLINE(S,short int) +MAKE_OUTLINE(US,unsigned short int) +MAKE_OUTLINE(B,signed char) +MAKE_OUTLINE(UB,unsigned char) +MAKE_OUTLINE(F,float) + +/* Undefine the macros. */ +#undef MAKE_OUTLINE + +/* +* Name: +* PartHull + +* Purpose: +* Find the convex hull enclosing selected pixels in one corner of a 2D array. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void PartHull<Oper><X>( <Xtype> value, const <Xtype> array[], int xdim, +* int ydim, int xs, int ys, int xe, int ye, +* int starpix, const int lbnd[2], double **xvert, +* double **yvert, int *nvert, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function uses an algorithm similar to "Andrew's Monotone Chain +* Algorithm" to create a list of vertices describing one corner of the +* convex hull enclosing the selected pixels in the supplied array. +* The corner is defined to be the area of the array to the right of +* the line from (xs,ys) to (xe,ye). + +* Parameters: +* value +* A data value that specifies the pixels to be selected. +* array +* Pointer to a 2-dimensional array containing the data to be +* processed. The numerical type of this array should match the 1- +* or 2-character type code appended to the function name. +* xdim +* The number of pixels along each row of the array. +* ydim +* The number of rows in the array. +* xs +* The X GRID index of the first pixel on the line to be checked. +* ys +* The Y GRID index of the first pixel on the line to be checked. +* xe +* The X GRID index of the last pixel on the line to be checked. +* ye +* The Y GRID index of the last pixel on the line to be checked. +* starpix +* If non-zero, the usual Starlink definition of pixel coordinate +* is used (integral values at pixel corners). Otherwise, the +* system used by other AST functions such as astResample is used +* (integral values at pixel centres). +* lbnd +* The lower pixel index bounds of the array. +* xvert +* Address of a pointer in which to return a pointer to the list +* of GRID x values on the hull. +* yvert +* Address of a pointer in which to return a pointer to the list +* of GRID y values on the hull. +* nvert +* Address of a pointer in which to return the number of points in +* the returned xvert and yvert arrays. +* status +* Pointer to the inherited status variable. + +*/ + +/* Define a macro to implement the function for a specific data + type and operation. */ +#define MAKE_PARTHULL(X,Xtype,Oper,OperI) \ +static void PartHull##Oper##X( Xtype value, const Xtype array[], int xdim, \ + int ydim, int xs, int ys, int xe, int ye, \ + int starpix, const int lbnd[2], \ + double **xvert, double **yvert, int *nvert, \ + int *status ) { \ +\ +/* Local Variables: */ \ + const Xtype *pc; \ + double *pxy; \ + double dx2; \ + double dx1; \ + double dy1; \ + double dy2; \ + double off; \ + double xdelta; \ + int ivert; \ + int ix; \ + int iy; \ + int x0; \ + int x1; \ + int xl; \ + int xlim; \ + int xr; \ + int yinc; \ +\ +/* Initialise */ \ + *yvert = NULL; \ + *xvert = NULL; \ + *nvert = 0; \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return; \ +\ +/* If the line has zero length. just return a single vertex. */ \ + if( xs == xe && ys == ye ) { \ + *xvert = astMalloc( sizeof( double ) ); \ + *yvert = astMalloc( sizeof( double ) ); \ + if( astOK ) { \ + if( starpix ) { \ + (*xvert)[ 0 ] = xs + lbnd[ 0 ] - 1.5; \ + (*yvert)[ 0 ] = ys + lbnd[ 1 ] - 1.5; \ + } else { \ + (*xvert)[ 0 ] = xs + lbnd[ 0 ] - 1.0; \ + (*yvert)[ 0 ] = ys + lbnd[ 1 ] - 1.0; \ + } \ + *nvert = 1; \ + } \ + return; \ + } \ +\ +/* Otherwise check the line is sloping. */ \ + if( xs == xe ) { \ + astError( AST__INTER, "astOutline(Polygon): Bounding box " \ + "has zero width (internal AST programming error).", \ + status ); \ + return; \ + } else if( ys == ye ) { \ + astError( AST__INTER, "astOutline(Polygon): Bounding box " \ + "has zero height (internal AST programming error).", \ + status ); \ + return; \ + } \ +\ +/* Calculate the difference in length between adjacent rows of the area \ + to be tested. */ \ + xdelta = ((double)( xe - xs ))/((double)( ye - ys )); \ +\ +/* The left and right X limits */ \ + if( xe > xs ) { \ + xl = xs; \ + xr = xe; \ + } else { \ + xl = xe; \ + xr = xs; \ + } \ +\ +/* Get the increment in row number as we move from the start to the end \ + of the line. */ \ + yinc = ( ye > ys ) ? 1 : -1; \ +\ +/* Loop round all rows that cross the region to be tested, from start to \ + end of the supplied line. */ \ + iy = ys; \ + while( astOK ) { \ +\ +/* Get the GRID X coord where the line crosses this row. */ \ + xlim = (int)( 0.5 + xs + xdelta*( iy - ys ) ); \ +\ +/* Get the index of the first and last columns to be tested on this row. */ \ + if( yinc < 0 ) { \ + x0 = xl; \ + x1 = xlim; \ + } else { \ + x0 = xlim; \ + x1 = xr; \ + } \ +\ +/* Get a pointer to the first pixel to be tested at this row. */ \ + pc = array + ( iy - 1 )*xdim + x0 - 1; \ +\ +/* Loop round all columns to be tested in this row. */ \ + for( ix = x0; ix <= x1 && astOK; ix++,pc++ ) { \ +\ +/* Ignore pixels that are not selected. */ \ + if( ISVALID(*pc,OperI,value) ) { \ +\ +/* If this is the very first pixel, initialise the hull to contain just \ + the first pixel. */ \ + if( *nvert == 0 ){ \ + *xvert = astMalloc( 200*sizeof( double ) ); \ + *yvert = astMalloc( 200*sizeof( double ) ); \ + if( astOK ) { \ + (*xvert)[ 0 ] = ix; \ + (*yvert)[ 0 ] = iy; \ + *nvert = 1; \ + } else { \ + break; \ + } \ +\ +/* Otherwise.... */ \ + } else { \ +\ +/* Loop until the hull has been corrected to include the current pixel. */ \ + while( 1 ) { \ +\ +/* If the hull currently contains only one pixel, add the current pixel to \ + the end of the hull. */ \ + if( *nvert == 1 ){ \ + (*xvert)[ 1 ] = ix; \ + (*yvert)[ 1 ] = iy; \ + *nvert = 2; \ + break; \ +\ +/* Otherwise... */ \ + } else { \ +\ +/* Extend the line from the last-but-one pixel on the hull to the last \ + pixel on the hull, and see if the current pixel is to the left of \ + this line. If it is, it too is on the hull and so push it onto the end \ + of the list of vertices. */ \ + dx1 = (*xvert)[ *nvert - 1 ] - (*xvert)[ *nvert - 2 ]; \ + dy1 = (*yvert)[ *nvert - 1 ] - (*yvert)[ *nvert - 2 ]; \ + dx2 = ix - (*xvert)[ *nvert - 2 ]; \ + dy2 = iy - (*yvert)[ *nvert - 2 ]; \ +\ + if( dx1*dy2 > dx2*dy1 ) { \ + ivert = (*nvert)++; \ + *xvert = astGrow( *xvert, *nvert, sizeof( double ) ); \ + *yvert = astGrow( *yvert, *nvert, sizeof( double ) ); \ + if( astOK ) { \ + (*xvert)[ ivert ] = ix; \ + (*yvert)[ ivert ] = iy; \ + } \ +\ +/* Leave the loop now that the new point is on the hull. */ \ + break; \ +\ +/* If the new point is to the left of the line, then the last point \ + previously thought to be on hull is in fact not on the hull, so remove \ + it. We then loop again to compare the new pixel with modified hull. */ \ + } else { \ + (*nvert)--; \ + } \ + } \ + } \ + } \ + } \ + } \ +\ + if( iy == ye ) { \ + break; \ + } else { \ + iy += yinc; \ + } \ +\ + } \ +\ +/* Convert GRID coords to PIXEL coords. */ \ + if( astOK ) { \ + pxy = *xvert; \ + off = starpix ? lbnd[ 0 ] - 1.5 : lbnd[ 0 ] - 1.0; \ + for( ivert = 0; ivert < *nvert; ivert++ ) *(pxy++) += off; \ +\ + pxy = *yvert; \ + off = starpix ? lbnd[ 1 ] - 1.5 : lbnd[ 1 ] - 1.0; \ + for( ivert = 0; ivert < *nvert; ivert++ ) *(pxy++) += off; \ +\ +/* Free lists if an error has occurred. */ \ + } else { \ + *xvert = astFree( *xvert ); \ + *yvert = astFree( *yvert ); \ + *nvert = 0; \ + } \ +} + +/* Define a macro that uses the above macro to to create implementations + of PartHull for all operations. */ +#define MAKEALL_PARTHULL(X,Xtype) \ +MAKE_PARTHULL(X,Xtype,LT,AST__LT) \ +MAKE_PARTHULL(X,Xtype,LE,AST__LE) \ +MAKE_PARTHULL(X,Xtype,EQ,AST__EQ) \ +MAKE_PARTHULL(X,Xtype,NE,AST__NE) \ +MAKE_PARTHULL(X,Xtype,GE,AST__GE) \ +MAKE_PARTHULL(X,Xtype,GT,AST__GT) + +/* Expand the above macro to generate a function for each required + data type and operation. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKEALL_PARTHULL(LD,long double) +#endif +MAKEALL_PARTHULL(D,double) +MAKEALL_PARTHULL(L,long int) +MAKEALL_PARTHULL(UL,unsigned long int) +MAKEALL_PARTHULL(I,int) +MAKEALL_PARTHULL(UI,unsigned int) +MAKEALL_PARTHULL(S,short int) +MAKEALL_PARTHULL(US,unsigned short int) +MAKEALL_PARTHULL(B,signed char) +MAKEALL_PARTHULL(UB,unsigned char) +MAKEALL_PARTHULL(F,float) + +/* Undefine the macros. */ +#undef MAKE_PARTHULL +#undef MAKEALL_PARTHULL + +static double Polywidth( AstFrame *frm, AstLineDef **edges, int i, int nv, + double cen[ 2 ], int *status ){ +/* +* Name: +* Polywidth + +* Purpose: +* Find the width of a polygon perpendicular to a given edge. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* double Polywidth( AstFrame *frm, AstLineDef **edges, int i, int nv, +* double cen[ 2 ], int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function defines a line perpendicular to a given polygon edge, +* passing through the mid point of the edge, extending towards the +* inside of the polygon. It returns the distance that can be travelled +* along this line before any of the other polygon edges are hit (the +* "width" of the polygon perpendicular to the given edge). It also +* puts the position corresponding to half that distance into "cen". + +* Parameters: +* frm +* The Frame in which the lines are defined. +* edges +* Array of "nv" pointers to AstLineDef structures, each defining an +* edge of the polygon. +* i +* The index of the edge that is to define the polygon width. +* nv +* Total number of edges. +* cen +* An array into which are put the coords of the point half way +* along the polygon width line. +* status +* Pointer to the inherited status variable. + +* Returnd Value: +* The width of the polygon perpendicular to the given edge, or +* AST__BAD if the width cannot be determined (usually because the +* vertices been supplied in a clockwise direction, effectively +* negating the Polygon). + +*/ + +/* Local Variables: */ + AstLineDef *line; + double *cross; + double d; + double end[ 2 ]; + double l1; + double l2; + double result; + double start[ 2 ]; + int j; + +/* Check the global error status. */ + result = AST__BAD; + if ( !astOK ) return result; + +/* Create a Line description for a line perpendicular to the specified + edge, passing through the mid point of the edge, and extending towards + the inside of the polygon. First move away from the start along the + line to the mid point. This gives the start of the new line. */ + l1 = 0.5*( edges[ i ]->length ); + astLineOffset( frm, edges[ i ], l1, 0.0, start ); + +/* We now move away from this position at right angles to the line. We + start off by moving 5 times the length of the specified edge. For + some Frames (e.g. SkyFrames) this may result in a position that is + much too close (i.e. if it goes all the way round the great circle + and comes back to the beginning). Therefore, we check that the end + point is the requested distance from the start point, and if not, we + halve the length of the line and try again. */ + l2 = 10.0*l1; + while( 1 ) { + astLineOffset( frm, edges[ i ], l1, l2, end ); + d = astDistance( frm, start, end ); + if( d != AST__BAD && fabs( d - l2 ) < 1.0E-6*l2 ) break; + l2 *= 0.5; + } + +/* Create a description of the required line. */ + line = astLineDef( frm, start, end ); + +/* Loop round every edge, except for the supplied edge. */ + for( j = 0; j < nv; j++ ) { + if( j != i ) { + +/* Find the position at which the line created above crosses the current + edge. Skip to the next edge if the line does not intersect the edge + within the length of the edge. */ + if( astLineCrossing( frm, line, edges[ j ], &cross ) ) { + +/* Find the distance between the crossing point and the line start. */ + d = astDistance( frm, start, cross ); + +/* If this is less than the smallest found so far, record it. */ + if( d != AST__BAD && ( d < result || result == AST__BAD ) ) { + result = d; + } + } + +/* Free resources */ + cross = astFree( cross ); + } + } + line = astFree( line ); + +/* If a width was found, return the point half way across the polygon. */ + if( result != AST__BAD ) { + astOffset( frm, start, end, 0.5*result, cen ); + +/* The usual reason for not finding a width is if the polygon vertices + are supplied in clockwise order, effectively negating the polygon, and + resulting in the "inside" of the polygon being the infinite region + outside a polygonal hole. In this case, the end point of the line + perpendicular to the initial edge can be returned as a representative + "inside" point. */ + } else { + cen[ 0 ] = end[ 0 ]; + cen[ 1 ] = end[ 1 ]; + } + +/* Return the width. */ + return result; + +} + +static void RegBaseBox( AstRegion *this_region, double *lbnd, double *ubnd, int *status ){ +/* +* Name: +* RegBaseBox + +* Purpose: +* Returns the bounding box of an un-negated Region in the base Frame of +* the encapsulated FrameSet. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void RegBaseBox( AstRegion *this, double *lbnd, double *ubnd, int *status ) + +* Class Membership: +* Polygon member function (over-rides the astRegBaseBox protected +* method inherited from the Region class). + +* Description: +* This function returns the upper and lower axis bounds of a Region in +* the base Frame of the encapsulated FrameSet, assuming the Region +* has not been negated. That is, the value of the Negated attribute +* is ignored. + +* Parameters: +* this +* Pointer to the Region. +* lbnd +* Pointer to an array in which to return the lower axis bounds +* covered by the Region in the base Frame of the encapsulated +* FrameSet. It should have at least as many elements as there are +* axes in the base Frame. +* ubnd +* Pointer to an array in which to return the upper axis bounds +* covered by the Region in the base Frame of the encapsulated +* FrameSet. It should have at least as many elements as there are +* axes in the base Frame. +* status +* Pointer to the inherited status variable. + +*/ + +/* Local Variables: */ + AstFrame *frm; /* Pointer to encapsulated Frame */ + AstPointSet *pset; /* Pointer to PointSet defining the Region */ + AstPolygon *this; /* Pointer to Polygon structure */ + AstRegion *reg; /* Base Frame equivalent of supplied Polygon */ + double **ptr; /* Pointer to PointSet data */ + double *x; /* Pointer to next X axis value */ + double *y; /* Pointer to next Y axis value */ + double dist; /* Offset along an axis */ + double x0; /* The first X axis value */ + double y0; /* The first Y axis value */ + int ip; /* Point index */ + int np; /* No. of points in PointSet */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Get a pointer to the Polygon structure. */ + this = (AstPolygon *) this_region; + +/* If the base Frame bounding box has already been found, return the + values stored in the Polygon structure. */ + if( this->lbnd[ 0 ] != AST__BAD ) { + lbnd[ 0 ] = this->lbnd[ 0 ]; + lbnd[ 1 ] = this->lbnd[ 1 ]; + ubnd[ 0 ] = this->ubnd[ 0 ]; + ubnd[ 1 ] = this->ubnd[ 1 ]; + +/* If the base Frame bounding box has not yet been found, find it now and + store it in the Polygon structure. */ + } else { + +/* Get the axis values for the PointSet which defines the location and + extent of the region in the base Frame of the encapsulated FrameSet. */ + pset = this_region->points; + ptr = astGetPoints( pset ); + np = astGetNpoint( pset ); + +/* Get a pointer to the base Frame in the frameset encapsulated by the + parent Region structure. */ + frm = astGetFrame( this_region->frameset, AST__BASE ); + +/* Find the upper and lower bounds of the box enclosing all the vertices. + The box is expressed in terms of axis offsets from the first vertex, in + order to avoid problems with boxes that cross RA=0 or RA=12h */ + lbnd[ 0 ] = 0.0; + lbnd[ 1 ] = 0.0; + ubnd[ 0 ] = 0.0; + ubnd[ 1 ] = 0.0; + + x = ptr[ 0 ]; + y = ptr[ 1 ]; + + x0 = *x; + y0 = *y; + + for( ip = 0; ip < np; ip++, x++, y++ ) { + + dist = astAxDistance( frm, 1, x0, *x ); + if( dist < lbnd[ 0 ] ) { + lbnd[ 0 ] = dist; + } else if( dist > ubnd[ 0 ] ) { + ubnd[ 0 ] = dist; + } + + dist = astAxDistance( frm, 2, y0, *y ); + if( dist < lbnd[ 1 ] ) { + lbnd[ 1 ] = dist; + } else if( dist > ubnd[ 1 ] ) { + ubnd[ 1 ] = dist; + } + + } + +/* Convert the box bounds to absolute values, rather than values relative + to the first vertex. */ + lbnd[ 0 ] += x0; + lbnd[ 1 ] += y0; + ubnd[ 0 ] += x0; + ubnd[ 1 ] += y0; + +/* The astNormBox requires a Mapping which can be used to test points in + this base Frame. Create a copy of the Polygon and then set its + FrameSet so that the current Frame in the copy is the same as the base + Frame in the original. */ + reg = astCopy( this ); + astSetRegFS( reg, frm ); + astSetNegated( reg, 0 ); + +/* Normalise this box. */ + astNormBox( frm, lbnd, ubnd, reg ); + +/* Free resources */ + reg = astAnnul( reg ); + frm = astAnnul( frm ); + +/* Store it in the olygon structure for future use. */ + this->lbnd[ 0 ] = lbnd[ 0 ]; + this->lbnd[ 1 ] = lbnd[ 1 ]; + this->ubnd[ 0 ] = ubnd[ 0 ]; + this->ubnd[ 1 ] = ubnd[ 1 ]; + + } +} + +static AstPointSet *RegBaseMesh( AstRegion *this_region, int *status ){ +/* +* Name: +* RegBaseMesh + +* Purpose: +* Return a PointSet containing a mesh of points on the boundary of a +* Region in its base Frame. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* AstPointSet *astRegBaseMesh( AstRegion *this, int *status ) + +* Class Membership: +* Polygon member function (over-rides the astRegBaseMesh protected +* method inherited from the Region class). + +* Description: +* This function returns a PointSet containing a mesh of points on the +* boundary of the Region. The points refer to the base Frame of +* the encapsulated FrameSet. + +* Parameters: +* this +* Pointer to the Region. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Pointer to the PointSet. Annul the pointer using astAnnul when it +* is no longer needed. + +* Notes: +* - A NULL pointer is returned if an error has already occurred, or if +* this function should fail for any reason. + +*/ + +/* Local Variables: */ + AstFrame *frm; /* Base Frame in encapsulated FrameSet */ + AstPointSet *result; /* Returned pointer */ + AstPolygon *this; /* The Polygon structure */ + double **rptr; /* Pointers to returned mesh data */ + double **vptr; /* Pointers to vertex data */ + double *lens; /* Pointer to work space holding edge lengths */ + double d; /* Length of this edge */ + double delta; /* Angular separation of points */ + double end[ 2 ]; /* End position */ + double mp; /* No. of mesh points per unit distance */ + double p[ 2 ]; /* Position in 2D Frame */ + double start[ 2 ]; /* Start position */ + double total; /* Total length of polygon */ + int ip; /* Point index */ + int iv; /* Vertex index */ + int n; /* No. of points on this edge */ + int next; /* Index of next point in returned PointSet */ + int np; /* No. of points in returned PointSet */ + int nv; /* No. of polygon vertices */ + +/* Initialise */ + result= NULL; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* If the Region structure contains a pointer to a PointSet holding + a previously created mesh, return it. */ + if( this_region->basemesh ) { + result = astClone( this_region->basemesh ); + +/* Otherwise, create a new mesh. */ + } else { + +/* Get a pointer to the Polygon structure. */ + this = (AstPolygon *) this_region; + +/* Get a pointer to the base Frame in the encapsulated FrameSet. */ + frm = astGetFrame( this_region->frameset, AST__BASE ); + +/* Get the number of vertices and pointers to the vertex axis values. */ + nv = astGetNpoint( this_region->points ); + vptr = astGetPoints( this_region->points ); + +/* Allocate memory to hold the geodesic length of each edge. */ + lens = astMalloc( sizeof( double )*(size_t) nv ); + + if( astOK ) { + +/* Find the total geodesic distance around the boundary. */ + total = 0.0; + + start[ 0 ] = vptr[ 0 ][ 0 ]; + start[ 1 ] = vptr[ 1 ][ 0 ]; + + for( iv = 1; iv < nv; iv++ ) { + end[ 0 ] = vptr[ 0 ][ iv ]; + end[ 1 ] = vptr[ 1 ][ iv ]; + + d = astDistance( frm, start, end ); + if( d != AST__BAD ) total += fabs( d ); + lens[ iv ] = d; + start[ 0 ] = end[ 0 ]; + start[ 1 ] = end[ 1 ]; + } + + end[ 0 ] = vptr[ 0 ][ 0 ]; + end[ 1 ] = vptr[ 1 ][ 0 ]; + + d = astDistance( frm, start, end ); + if( d != AST__BAD ) total += fabs( d ); + lens[ 0 ] = d; + +/* Find the number of mesh points per unit geodesic distance. */ + if( total > 0.0 ){ + mp = astGetMeshSize( this )/total; + +/* Find the total number of mesh points required. */ + np = 0; + for( iv = 0; iv < nv; iv++ ) { + if( lens[ iv ] != AST__BAD ) np += 1 + (int)( lens[ iv ]*mp ); + } + +/* Create a suitable PointSet to hold the returned positions. */ + result = astPointSet( np, 2, "", status ); + rptr = astGetPoints( result ); + if( astOK ) { + +/* Initialise the index of the next point to be added to the returned + PointSet. */ + next = 0; + +/* Loop round each good edge of the polygon. The edge ends at vertex "iv". */ + start[ 0 ] = vptr[ 0 ][ 0 ]; + start[ 1 ] = vptr[ 1 ][ 0 ]; + + for( iv = 1; iv < nv; iv++ ) { + end[ 0 ] = vptr[ 0 ][ iv ]; + end[ 1 ] = vptr[ 1 ][ iv ]; + if( lens[ iv ] != AST__BAD ) { + +/* Add the position of the starting vertex to the returned mesh. */ + rptr[ 0 ][ next ] = start[ 0 ]; + rptr[ 1 ][ next ] = start[ 1 ]; + next++; + +/* Find the number of points on this edge, and the geodesic distance + between them. */ + n = 1 + (int) ( lens[ iv ]*mp ); + +/* If more than one point, find the distance between points. */ + if( n > 1 ) { + delta = lens[ iv ]/n; + +/* Loop round the extra points. */ + for( ip = 1; ip < n; ip++ ) { + +/* Find the position of the next mesh point. */ + astOffset( frm, start, end, delta*ip, p ); + +/* Add it to the mesh. */ + rptr[ 0 ][ next ] = p[ 0 ]; + rptr[ 1 ][ next ] = p[ 1 ]; + next++; + + } + } + } + +/* The end of this edge becomes the start of the next. */ + start[ 0 ] = end[ 0 ]; + start[ 1 ] = end[ 1 ]; + } + +/* Now do the edge which ends at the first vertex. */ + end[ 0 ] = vptr[ 0 ][ 0 ]; + end[ 1 ] = vptr[ 1 ][ 0 ]; + if( lens[ 0 ] != AST__BAD ) { + rptr[ 0 ][ next ] = start[ 0 ]; + rptr[ 1 ][ next ] = start[ 1 ]; + next++; + + n = 1 + (int)( lens[ 0 ]*mp ); + if( n > 1 ) { + delta = lens[ 0 ]/n; + for( ip = 1; ip < n; ip++ ) { + astOffset( frm, start, end, delta*ip, p ); + rptr[ 0 ][ next ] = p[ 0 ]; + rptr[ 1 ][ next ] = p[ 1 ]; + next++; + } + } + } + +/* Check the PointSet size was correct. */ + if( next != np && astOK ) { + astError( AST__INTER, "astRegBaseMesh(%s): Error in the " + "allocated PointSet size (%d) - should have " + "been %d (internal AST programming error).", status, + astGetClass( this ), np, next ); + } + +/* Save the returned pointer in the Region structure so that it does not + need to be created again next time this function is called. */ + if( astOK ) this_region->basemesh = astClone( result ); + + } + + } else if( astOK ) { + astError( AST__BADIN, "astRegBaseMesh(%s): The boundary of " + "the supplied %s has an undefined length.", status, + astGetClass( this ), astGetClass( this ) ); + } + + } + +/* Free resources. */ + frm = astAnnul( frm ); + lens = astFree( lens ); + } + +/* Annul the result if an error has occurred. */ + if( !astOK ) result = astAnnul( result ); + +/* Return a pointer to the output PointSet. */ + return result; +} + +static int RegPins( AstRegion *this_region, AstPointSet *pset, AstRegion *unc, + int **mask, int *status ){ +/* +* Name: +* RegPins + +* Purpose: +* Check if a set of points fall on the boundary of a given Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* int RegPins( AstRegion *this, AstPointSet *pset, AstRegion *unc, +* int **mask, int *status ) + +* Class Membership: +* Polygon member function (over-rides the astRegPins protected +* method inherited from the Region class). + +* Description: +* This function returns a flag indicating if the supplied set of +* points all fall on the boundary of the given Polygon. +* +* Some tolerance is allowed, as specified by the uncertainty Region +* stored in the supplied Polygon "this", and the supplied uncertainty +* Region "unc" which describes the uncertainty of the supplied points. + +* Parameters: +* this +* Pointer to the Polygon. +* pset +* Pointer to the PointSet. The points are assumed to refer to the +* base Frame of the FrameSet encapsulated by "this". +* unc +* Pointer to a Region representing the uncertainties in the points +* given by "pset". The Region is assumed to represent the base Frame +* of the FrameSet encapsulated by "this". Zero uncertainity is assumed +* if NULL is supplied. +* mask +* Pointer to location at which to return a pointer to a newly +* allocated dynamic array of ints. The number of elements in this +* array is equal to the value of the Npoint attribute of "pset". +* Each element in the returned array is set to 1 if the +* corresponding position in "pset" is on the boundary of the Region +* and is set to zero otherwise. A NULL value may be supplied +* in which case no array is created. If created, the array should +* be freed using astFree when no longer needed. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Non-zero if the points all fall on the boundary of the given +* Region, to within the tolerance specified. Zero otherwise. + +*/ + +/* Local variables: */ + AstFrame *frm; /* Base Frame in supplied Polygon */ + AstPointSet *pset1; /* Pointer to copy of supplied PointSet */ + AstPointSet *pset2; /* Pointer to PointSet holding resolved components */ + AstPolygon *this; /* Pointer to the Polygon structure. */ + AstRegion *tunc; /* Uncertainity Region from "this" */ + double **ptr1; /* Pointer to axis values in "pset1" */ + double **ptr2; /* Pointer to axis values in "pset2" */ + double **vptr; /* Pointer to axis values at vertices */ + double *safe; /* An interior point in "this" */ + double edge_len; /* Length of current edge */ + double end[2]; /* Position of end of current edge */ + double l1; /* Length of bounding box diagonal */ + double l2; /* Length of bounding box diagonal */ + double lbnd_tunc[2]; /* Lower bounds of "this" uncertainty Region */ + double lbnd_unc[2]; /* Lower bounds of supplied uncertainty Region */ + double par; /* Parallel component */ + double parmax; /* Max acceptable parallel component */ + double prp; /* Perpendicular component */ + double start[2]; /* Position of start of current edge */ + double ubnd_tunc[2]; /* Upper bounds of "this" uncertainty Region */ + double ubnd_unc[2]; /* Upper bounds of supplied uncertainty Region */ + double wid; /* Width of acceptable margin around polygon */ + int *m; /* Pointer to next mask value */ + int i; /* Edge index */ + int ip; /* Point index */ + int np; /* No. of supplied points */ + int nv; /* No. of vertices */ + int result; /* Returned flag */ + +/* Initialise */ + result = 0; + if( mask ) *mask = NULL; + +/* Check the inherited status. */ + if( !astOK ) return result; + +/* Get a pointer to the Polygon structure. */ + this = (AstPolygon *) this_region; + +/* Check the supplied PointSet has 2 axis values per point. */ + if( astGetNcoord( pset ) != 2 && astOK ) { + astError( AST__INTER, "astRegPins(%s): Illegal number of axis " + "values per point (%d) in the supplied PointSet - should be " + "2 (internal AST programming error).", status, astGetClass( this ), + astGetNcoord( pset ) ); + } + +/* Get the number of axes in the uncertainty Region and check it is also 2. */ + if( unc && astGetNaxes( unc ) != 2 && astOK ) { + astError( AST__INTER, "astRegPins(%s): Illegal number of axes (%d) " + "in the supplied uncertainty Region - should be 2 " + "(internal AST programming error).", status, astGetClass( this ), + astGetNaxes( unc ) ); + } + +/* Get pointers to the axis values at the polygon vertices. */ + vptr = astGetPoints( this_region->points ); + +/* Get the number of vertices. */ + nv = astGetNpoint( this_region->points ); + +/* Take a copy of the supplied PointSet and get pointers to its axis + values,and its size */ + pset1 = astCopy( pset ); + ptr1 = astGetPoints( pset1 ); + np = astGetNpoint( pset1 ); + +/* Create a PointSet to hold the resolved components and get pointers to its + axis data. */ + pset2 = astPointSet( np, 2, "", status ); + ptr2 = astGetPoints( pset2 ); + +/* Create a mask array if required. */ + if( mask ) *mask = astMalloc( sizeof(int)*(size_t) np ); + +/* Get the centre of the region in the base Frame. We use this as a "safe" + interior point within the region. */ + safe = astRegCentre( this, NULL, NULL, 0, AST__BASE ); + +/* We now find the maximum distance on each axis that a point can be from the + boundary of the Polygon for it still to be considered to be on the boundary. + First get the Region which defines the uncertainty within the Polygon + being checked (in its base Frame), re-centre it on the interior point + found above (to avoid problems if the uncertainty region straddles a + discontinuity), and get its bounding box. The current Frame of the + uncertainty Region is the same as the base Frame of the Polygon. */ + tunc = astGetUncFrm( this, AST__BASE ); + if( safe ) astRegCentre( tunc, safe, NULL, 0, AST__CURRENT ); + astGetRegionBounds( tunc, lbnd_tunc, ubnd_tunc ); + +/* Find the geodesic length within the base Frame of "this" of the diagonal of + the bounding box. */ + frm = astGetFrame( this_region->frameset, AST__BASE ); + l1 = astDistance( frm, lbnd_tunc, ubnd_tunc ); + +/* Also get the Region which defines the uncertainty of the supplied + points and get its bounding box. First re-centre the uncertainty at the + interior position to avoid problems from uncertainties that straddle a + discontinuity. */ + if( unc ) { + if( safe ) astRegCentre( unc, safe, NULL, 0, AST__CURRENT ); + astGetRegionBounds( unc, lbnd_unc, ubnd_unc ); + +/* Find the geodesic length of the diagonal of this bounding box. */ + l2 = astDistance( frm, lbnd_unc, ubnd_unc ); + +/* Assume zero uncertainty if no "unc" Region was supplied. */ + } else { + l2 = 0.0; + } + +/* The required border width is half of the total diagonal of the two bounding + boxes. */ + if( astOK ) { + wid = 0.5*( l1 + l2 ); + +/* Loop round each edge of the polygon. Edge "i" starts at vertex "i-1" + and ends at vertex "i". Edge zero starts at vertex "nv-1" and ends at + vertex zero. */ + start[ 0 ] = vptr[ 0 ][ nv - 1 ]; + start[ 1 ] = vptr[ 1 ][ nv - 1 ]; + for( i = 0; i < nv; i++ ) { + end[ 0 ] = vptr[ 0 ][ i ]; + end[ 1 ] = vptr[ 1 ][ i ]; + +/* Find the length of this edge. */ + edge_len = astDistance( frm, start, end ); + +/* Resolve all the supplied mesh points into components parallel and + perpendicular to this edge. */ + (void) astResolvePoints( frm, start, end, pset1, pset2 ); + +/* A point is effectively on this edge if the parallel component is + greater than (-wid) and less than (edge_len+wid) AND the perpendicular + component has an absolute value less than wid. Identify such positions + and set them bad in pset1. */ + parmax = edge_len + wid; + for( ip = 0; ip < np; ip++ ) { + par = ptr2[ 0 ][ ip ]; + prp = ptr2[ 1 ][ ip ]; + + if( par != AST__BAD && prp != AST__BAD ) { + if( par > -wid && par < parmax && prp > -wid && prp < wid ) { + ptr1[ 0 ][ ip ] = AST__BAD; + ptr1[ 1 ][ ip ] = AST__BAD; + } + } + } + +/* The end of the current edge becomes the start of the next. */ + start[ 0 ] = end[ 0 ]; + start[ 1 ] = end[ 1 ]; + } + +/* See if any good points are left in pset1. If so, it means that those + points were not on any edge of hte Polygon. We use two alogorithms + here depending on whether we are creating a mask array, since we can + abort the check upon finding the first good point if we are not + producing a mask. */ + result = 1; + if( mask ) { + m = *mask; + for( ip = 0; ip < np; ip++, m++ ) { + if( ptr1[ 0 ][ ip ] != AST__BAD && + ptr1[ 1 ][ ip ] != AST__BAD ) { + *m = 0; + result = 0; + } else { + *m = 1; + } + } + } else { + for( ip = 0; ip < np; ip++ ) { + if( ptr1[ 0 ][ ip ] != AST__BAD && + ptr1[ 1 ][ ip ] != AST__BAD ) { + result = 0; + break; + } + } + } + } + +/* Free resources. */ + tunc = astAnnul( tunc ); + frm = astAnnul( frm ); + safe = astFree( safe ); + pset1 = astAnnul( pset1 ); + pset2 = astAnnul( pset2 ); + +/* If an error has occurred, return zero. */ + if( !astOK ) { + result = 0; + if( mask ) *mask = astFree( *mask ); + } + +/* Return the result. */ + return result; +} + +static int RegTrace( AstRegion *this_region, int n, double *dist, double **ptr, + int *status ){ +/* +*+ +* Name: +* RegTrace + +* Purpose: +* Return requested positions on the boundary of a 2D Region. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* int astTraceRegion( AstRegion *this, int n, double *dist, double **ptr ); + +* Class Membership: +* Polygon member function (overrides the astTraceRegion method +* inherited from the parent Region class). + +* Description: +* This function returns positions on the boundary of the supplied +* Region, if possible. The required positions are indicated by a +* supplied list of scalar parameter values in the range zero to one. +* Zero corresponds to some arbitrary starting point on the boundary, +* and one corresponds to the end (which for a closed region will be +* the same place as the start). + +* Parameters: +* this +* Pointer to the Region. +* n +* The number of positions to return. If this is zero, the function +* returns without action (but the returned function value still +* indicates if the method is supported or not). +* dist +* Pointer to an array of "n" scalar parameter values in the range +* 0 to 1.0. +* ptr +* A pointer to an array of pointers. The number of elements in +* this array should equal tthe number of axes in the Frame spanned +* by the Region. Each element of the array should be a pointer to +* an array of "n" doubles, in which to return the "n" values for +* the corresponding axis. The contents of the arrays are unchanged +* if the supplied Region belongs to a class that does not +* implement this method. + +* Returned Value: +* Non-zero if the astTraceRegion method is implemented by the class +* of Region supplied, and zero if not. + +*- +*/ + +/* Local Variables; */ + AstFrame *frm; + AstMapping *map; + AstPointSet *bpset; + AstPointSet *cpset; + AstPolygon *this; + double **bptr; + double d; + double p[ 2 ]; + int i; + int j0; + int j; + int ncur; + int nv; + int monotonic; + +/* Check inherited status, and the number of points to return, returning + a non-zero value to indicate that this class supports the astRegTrace + method. */ + if( ! astOK || n == 0 ) return 1; + +/* Get a pointer to the Polygon structure. */ + this = (AstPolygon *) this_region; + +/* Ensure cached information is available. */ + Cache( this, status ); + +/* Get a pointer to the base Frame in the encapsulated FrameSet. */ + frm = astGetFrame( this_region->frameset, AST__BASE ); + +/* We first determine the required positions in the base Frame of the + Region, and then transform them into the current Frame. Get the + base->current Mapping, and the number of current Frame axes. */ + map = astGetMapping( this_region->frameset, AST__BASE, AST__CURRENT ); + +/* If it's a UnitMap we do not need to do the transformation, so put the + base Frame positions directly into the supplied arrays. */ + if( astIsAUnitMap( map ) ) { + bpset = NULL; + bptr = ptr; + ncur = 2; + +/* Otherwise, create a PointSet to hold the base Frame positions (known + to be 2D since this is an polygon). */ + } else { + bpset = astPointSet( n, 2, " ", status ); + bptr = astGetPoints( bpset ); + ncur = astGetNout( map ); + } + +/* Check the pointers can be used safely. */ + if( astOK ) { + +/* Get the number of vertices. */ + nv = astGetNpoint( this_region->points ); + +/* If we have a reasonable number of pointsand there are a reasonable + number of vertices, we can be quicker if we know if the parameteric + distances are monotonic increasing. Find out now. */ + if( n > 5 && nv > 5 ) { + + monotonic = 1; + for( i = 1; i < n; i++ ) { + if( dist[ i ] < dist[ i - 1 ] ) { + monotonic = 0; + break; + } + } + + } else { + monotonic = 0; + } + +/* Loop round each point. */ + j0 = 1; + for( i = 0; i < n; i++ ) { + +/* Get the required round the polygon, starting from vertex zero. */ + d = dist[ i ]*this->totlen; + +/* Loop round each vertex until we find one which is beyond the required + point. If the supplied distances are monotonic increasing, we can + start the checks at the same vertex that was used for the previous + since we know there will never be a backward step. */ + for( j = j0; j < nv; j++ ) { + if( this->startsat[ j ] > d ) break; + } + +/* If the distances are monotonic increasing, record the vertex that we + have reached so far. */ + if( monotonic ) j0 = j; + +/* Find the distance to travel beyond the previous vertex. */ + d -= this->startsat[ j - 1 ]; + +/* Find the position, that is the required distance from the previous + vertex towards the next vertex. */ + astLineOffset( frm, this->edges[ j - 1 ], d, 0.0, p ); + +/* Store the resulting axis values. */ + bptr[ 0 ][ i ] = p[ 0 ]; + bptr[ 1 ][ i ] = p[ 1 ]; + } + } + +/* If required, transform the base frame positions into the current + Frame, storing them in the supplied array. Then free resources. */ + if( bpset ) { + cpset = astPointSet( n, ncur, " ", status ); + astSetPoints( cpset, ptr ); + + (void) astTransform( map, bpset, 1, cpset ); + + cpset = astAnnul( cpset ); + bpset = astAnnul( bpset ); + } + +/* Free remaining resources. */ + map = astAnnul( map ); + frm = astAnnul( frm ); + +/* Return a non-zero value to indicate that this class supports the + astRegTrace method. */ + return 1; +} + +static Segment *RemoveFromChain( Segment *head, Segment *seg, int *status ){ +/* +* Name: +* RemoveFromChain + +* Purpose: +* Remove a Segment from the link list maintained by astDownsize. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* Segment *RemoveFromChain( Segment *head, Segment *seg, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* The supplied Segment is removed form the list, and the gap is +* closed up. + +* Parameters: +* head +* The Segment structure at the head of the list. +* seg +* The Segment to be removed from the list. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Pointer to the link head (which will have changed if "seg" was the +* original head). + +*/ + +/* Check the global error status. */ + if ( !astOK ) return head; + +/* If the Segment was the original head, make the next segment the new + head. */ + if( head == seg ) head = seg->next; + +/* Close up the links between the Segments on either side of the segment + being removed. */ + if( seg->prev ) seg->prev->next = seg->next; + if( seg->next ) seg->next->prev = seg->prev; + +/* Nullify the links in the segment being removed. */ + seg->next = NULL; + seg->prev = NULL; + +/* Return the new head. */ + return head; +} + +static void ResetCache( AstRegion *this_region, int *status ){ +/* +* Name: +* ResetCache + +* Purpose: +* Clear cached information within the supplied Region. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void ResetCache( AstRegion *this, int *status ) + +* Class Membership: +* Region member function (overrides the astResetCache method +* inherited from the parent Region class). + +* Description: +* This function clears cached information from the supplied Region +* structure. + +* Parameters: +* this +* Pointer to the Region. +* status +* Pointer to the inherited status variable. +*/ + +/* Local Variables: */ + AstPolygon *this; + int i; + int nv; + +/* Get a pointer to the Polygon structure. */ + this = (AstPolygon *) this_region; + +/* If a Polygon was supplied, indicate cached information needs to be + recalculated. */ + if( this ) { + this->stale = 1; + this->lbnd[ 0 ] = AST__BAD; + +/* Free any edge structures (number of vertices may be about to change so + this cannot be left until the next call to "Cache()". */ + if( this->edges ) { + nv = astGetNpoint( this_region->points ); + for( i = 0; i < nv; i++ ) { + this->edges[ i ] = astFree( this->edges[ i ] ); + } + this->edges = astFree( this->edges ); + } + +/* Clear the cache of the parent class. */ + (*parent_resetcache)( this_region, status ); + } +} + +static void SetAttrib( AstObject *this_object, const char *setting, int *status ) { +/* +* Name: +* SetAttrib + +* Purpose: +* Set an attribute value for a Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void SetAttrib( AstObject *this, const char *setting, int *status ) + +* Class Membership: +* Polygon member function (extends the astSetAttrib method inherited from +* the Region class). + +* Description: +* This function assigns an attribute value for a Polygon, the attribute +* and its value being specified by means of a string of the form: +* +* "attribute= value " +* +* Here, "attribute" specifies the attribute name and should be in lower +* case with no white space present. The value to the right of the "=" +* should be a suitable textual representation of the value to be assigned +* and this will be interpreted according to the attribute's data type. +* White space surrounding the value is only significant for string +* attributes. + +* Parameters: +* this +* Pointer to the Polygon. +* setting +* Pointer to a null terminated string specifying the new attribute +* value. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* void +*/ + +/* Local Vaiables: */ + AstPolygon *this; /* Pointer to the Polygon structure */ + int ival; /* Integer attribute value */ + int len; /* Length of setting string */ + int nc; /* Number of characters read by astSscanf */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) this_object; + +/* Obtain the length of the setting string. */ + len = strlen( setting ); + +/* Test for each recognised attribute in turn, using "astSscanf" to parse the + setting string and extract the attribute value (or an offset to it in the + case of string values). In each case, use the value set in "nc" to check + that the entire string was matched. Once a value has been obtained, use the + appropriate method to set it. */ + +/* SimpVertices. */ +/* ------------- */ + if ( nc = 0, + ( 1 == astSscanf( setting, "simpvertices= %d %n", &ival, &nc ) ) + && ( nc >= len ) ) { + astSetSimpVertices( this, ival ); + +/* Pass any unrecognised setting to the parent method for further + interpretation. */ + } else { + (*parent_setattrib)( this_object, setting, status ); + } +} + +static void SetPointSet( AstPolygon *this, AstPointSet *pset, int *status ){ +/* +* Name: +* SetPointSet + +* Purpose: +* Store a new set of vertices in an existing Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void SetPointSet( AstPolygon *this, AstPointSet *pset, int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* The PointSet in the supplied Polygon is annulled, and replaced by a +* clone of the supplied PointSet pointer. + +* Parameters: +* this +* Pointer to the Polygon to be changed. +* pset +* The PointSet containing the new vertex information. +* status +* Pointer to the inherited status variable. + +*/ + + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Indicate the cached information in the polygon will need to be + re-calculated when needed. */ + astResetCache( this ); + +/* Annul the pointer to the PointSet already in the supplied Polygon. */ + (void) astAnnul( ((AstRegion *) this)->points ); + +/* Store a clone of the supplied new PointSet pointer. */ + ((AstRegion *) this)->points = astClone( pset ); + +} + +static void SetRegFS( AstRegion *this_region, AstFrame *frm, int *status ) { +/* +* Name: +* SetRegFS + +* Purpose: +* Stores a new FrameSet in a Region + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void SetRegFS( AstRegion *this_region, AstFrame *frm, int *status ) + +* Class Membership: +* Polygon method (over-rides the astSetRegFS method inherited from +* the Region class). + +* Description: +* This function creates a new FrameSet and stores it in the supplied +* Region. The new FrameSet contains two copies of the supplied +* Frame, connected by a UnitMap. + +* Parameters: +* this +* Pointer to the Region. +* frm +* The Frame to use. +* status +* Pointer to the inherited status variable. + +*/ + + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Indicate cached information eeds re-calculating. */ + astResetCache( this_region ); + +/* Invoke the parent method to store the FrameSet in the parent Region + structure. */ + (* parent_setregfs)( this_region, frm, status ); + +} + +static AstMapping *Simplify( AstMapping *this_mapping, int *status ) { +/* +* Name: +* Simplify + +* Purpose: +* Simplify the Mapping represented by a Region. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* AstMapping *Simplify( AstMapping *this, int *status ) + +* Class Membership: +* Polygon method (over-rides the astSimplify method inherited +* from the Region class). + +* Description: +* This function invokes the parent Region Simplify method, and then +* performs any further region-specific simplification. +* +* If the Mapping from base to current Frame is not a UnitMap, this +* will include attempting to fit a new Region to the boundary defined +* in the current Frame. + +* Parameters: +* this +* Pointer to the original Region. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* A pointer to the simplified Region. A cloned pointer to the +* supplied Region will be returned if no simplication could be +* performed. + +* Notes: +* - A NULL pointer value will be returned if this function is +* invoked with the AST error status set, or if it should fail for +* any reason. +*/ + +/* Local Variables: */ + AstFrame *frm; /* Current Frame */ + AstMapping *map; /* Base -> current Mapping */ + AstMapping *result; /* Result pointer to return */ + AstPointSet *mesh; /* Mesh of current Frame positions */ + AstPointSet *ps2; /* Polygon PointSet in current Frame */ + AstPolygon *newpol; /* New Polygon */ + AstRegion *new; /* Pointer to simplified Region */ + AstRegion *this; /* Pointer to supplied Region structure */ + AstRegion *unc; /* Pointer to uncertainty Region */ + double **ptr2; /* Pointer axis values in "ps2" */ + double *mem; /* Pointer to array holding new vertex coords */ + double *p; /* Pointer to next vertex coords */ + double *q; /* Pointer to next vertex coords */ + int iv; /* Vertex index */ + int nv; /* Number of vertices in polygon */ + int ok; /* Are the new polygon vertices good? */ + int simpler; /* Has some simplication taken place? */ + +/* Initialise. */ + result = NULL; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* Get a pointer to the supplied Region structure. */ + this = (AstRegion *) this_mapping; + +/* Invoke the parent Simplify method inherited from the Region class. This + will simplify the encapsulated FrameSet and uncertainty Region. */ + new = (AstRegion *) (*parent_simplify)( this_mapping, status ); + +/* Note if any simplification took place. This is assumed to be the case + if the pointer returned by the above call is different to the supplied + pointer. */ + simpler = ( new != this ); + +/* We attempt to simplify the Polygon by re-defining it within its current + Frame. Transforming the Polygon from its base to its current Frame may + result in the region no having the same edges. If required, we test this + by transforming a set of bounds on the Polygon boundary. This can only + be done if the current Frame is 2-dimensional. Also, there is only any + point in doing it if the Mapping from base to current Frame in the + Polygon is not a UnitMap. */ + map = astGetMapping( new->frameset, AST__BASE, AST__CURRENT ); + if( !astIsAUnitMap( map ) && astGetNout( map ) == 2 ) { + +/* Get a pointer to the Frame represented by the Polgon. */ + frm = astGetFrame( new->frameset, AST__CURRENT ); + +/* Get the Region describing the positional uncertainty in this Frame. */ + unc = astGetUncFrm( new, AST__CURRENT ); + +/* Get the positions of the vertices within this Frame. */ + ps2 = astRegTransform( this, this->points, 1, NULL, NULL ); + ptr2 = astGetPoints( ps2 ); + +/* Get the number of vertices. */ + nv = astGetNpoint( ps2 ); + +/* Re-organise the vertex axis values into the form required by the + Polygon constructor function. */ + mem = astMalloc( sizeof( double)*(size_t)( 2*nv ) ); + if( astOK ) { + ok = 1; + p = mem; + q = ptr2[ 0 ]; + for( iv = 0; iv < nv; iv++ ) { + if( ( *(p++) = *(q++) ) == AST__BAD ) ok = 0; + } + q = ptr2[ 1 ]; + for( iv = 0; iv < nv; iv++ ) *(p++) = *(q++); + +/* Create a new Polygon using these transformed vertices. */ + if( ok ) { + newpol = astPolygon( frm, nv, nv, mem, unc, "", status ); + +/* If the SimpVertices attribute is zero, we now check that the + transformation has not bent the edges of the polygon significantly. + If it has, we annul the new Polygon. */ + if( !astGetSimpVertices( this ) ) { + +/* Get a mesh of points covering the Polygon in this Frame. */ + mesh = astRegMesh( new ); + +/* See if all points within the mesh created from the original Polygon fall + on the boundary of the new Polygon, to within the uncertainty of the + Region. If not, annul the new Polgon. */ + if( !astRegPins( newpol, mesh, NULL, NULL ) ) { + newpol = astAnnul( newpol ); + } + +/* Free the mesh. */ + mesh = astAnnul( mesh ); + } + +/* If we still have a new polygon, use the new Polygon in place of the + original Region. */ + if( newpol ) { + (void) astAnnul( new ); + new = (AstRegion *) newpol; + simpler = 1; + } + } + } + +/* Free other resources. */ + frm = astAnnul( frm ); + unc = astAnnul( unc ); + ps2 = astAnnul( ps2 ); + mem = astFree( mem ); + } + map = astAnnul( map ); + +/* If any simplification could be performed, copy Region attributes from + the supplied Region to the returned Region, and return a pointer to it. + If the supplied Region had no uncertainty, ensure the returned Region + has no uncertainty. Otherwise, return a clone of the supplied pointer. */ + if( simpler ){ + astRegOverlay( new, this, 1 ); + result = (AstMapping *) new; + + } else { + new = astAnnul( new ); + result = astClone( this ); + } + +/* If an error occurred, annul the returned pointer. */ + if ( !astOK ) result = astAnnul( result ); + +/* Return the result. */ + return result; +} + +static void SmoothPoly( AstPointSet *pset, int boxsize, double strength, + int *status ) { +/* +* Name: +* SmoothPoly + +* Purpose: +* Smoooth a polygon assuming plane geometry. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void SmoothPoly( AstPointSet *pset, int boxsize, double strength, +* int *status ) + +* Class Membership: +* Polygon member function + +* Description: +* This function smooths a polygon, without changing the number of +* vertices. It assumes plane geometry, so should not be used to +* smooth polygons defined within a SkyFrame or CmpFrame. +* +* Each vertex is replaced by a new vertex determined as follows: the +* mean X and Y axis value of the vertices in a section of the polygon +* centred on the vertex being replaced are found (the length of the +* section is given by parameter "boxsize"). The new vertex position +* is then the weighted mean of this mean (X,Y) position and the old +* vertex position. The weight for the mean (X,Y) position is given +* by parameter "strength", and the weight for the old vertex +* position is (1.0 - strength) + +* Parameters: +* pset +* A PointSet holding the polygon vertices. +* boxsize +* Half width of the box filter, given as a number of vertices. +* strength +* The weight to use for the mean (X,Y) position when finding each +* new vertex position. Should be in the range 0.0 to 1.0. A value +* of zero results in no change being made to the polygon. A value +* of 1.0 results in the returned polygon being fully smoothed. +* status +* Pointer to the inherited status variable. + +*/ + +/* Local Variables: */ + double **ptr; + double *newx; + double *newy; + double *nx; + double *ny; + double *oldx; + double *oldy; + double *ox; + double *oy; + double *px; + double *py; + double *qx; + double *qy; + double a; + double b; + double sx; + double sy; + int half_width; + int i; + int nv; + int top; + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Get the number of vertices. */ + nv = astGetNpoint( pset ); + +/* Get pointers to arrays holding the supplied vertex positions. */ + ptr = astGetPoints( pset ); + oldx = ptr[ 0 ]; + oldy = ptr[ 1 ]; + +/* Allocate arrays to hold the returned vertex positions. */ + newx = astMalloc( nv*sizeof( double ) ); + newy = astMalloc( nv*sizeof( double ) ); + +/* Check these pointers can be used safely. */ + if( astOK ) { + +/* Get weighting factors for the fully smoothed and unsmoothed positions. */ + a = strength; + b = 1.0 - a; + +/* Ensure the box size is sufficiently small for there to be room for + two boxes along the polygon. */ + half_width = nv/4 - 1; + if( boxsize < half_width ) half_width = boxsize; + if( half_width < 1 ) half_width = 1; + +/* Modify the weight for the fully smoothed position to include the + normalisation factor needed to account for the box width. */ + a /= 2*half_width + 1; + +/* Find the sum of the x and y coordinates within a box centred on the + first vertex. This includes vertices from the end of the polygon. */ + px = oldx + 1; + qx = oldx + nv; + sx = (oldx)[ 0 ]; + + py = oldy + 1; + qy = oldy + nv; + sy = (oldy)[ 0 ]; + + for( i = 0; i < half_width; i++ ) { + sx += *(px++) + *(--qx); + sy += *(py++) + *(--qy); + } + +/* Replacing vertices within the first half box will include vertices at + both ends of the polygon. Set up the pointers accordingly, and then + find replacements for each vertex in the first half box.*/ + ox = oldx; + oy = oldy; + nx = newx; + ny = newy; + for( i = 0; i < half_width; i++ ) { + +/* Form the new vertex (x,y) values as the weighted mean of the mean + (x,y) values in the box, and the old (x,y) values. */ + *(nx++) = a*sx + b*( *(ox++) ); + *(ny++) = a*sy + b*( *(oy++) ); + +/* Add in the next vertex X and Y axis values to the running sums, and + remove the position that has now passed out of the box. */ + sx += *(px++) - *(qx++); + sy += *(py++) - *(qy++); + } + +/* Adjust the pointer for the rest of the polygon, up to one half box away + from the end. In this section, the smoothing box does not touch either + end of the polygon. */ + top = nv - half_width - 1; + qx = oldx; + qy = oldy; + for( ; i < top; i++ ){ + +/* Form the new vertex (x,y) values as the weighted mean of the mean + (x,y) values in the box, and the old (x,y) values. */ + *(nx++) = a*sx + b*( *(ox++) ); + *(ny++) = a*sy + b*( *(oy++) ); + +/* Add in the next vertex X and Y axis values to the running sums, and + remove the position that has now passed out of the box. */ + sx += *(px++) - *(qx++); + sy += *(py++) - *(qy++); + } + +/* Now do the last half box (which includes vertices from the start of + the polygon). */ + top = nv; + px = oldx; + py = oldy; + for( ; i < top; i++ ){ + *(nx++) = a*sx + b*( *(ox++) ); + *(ny++) = a*sy + b*( *(oy++) ); + sx += *(px++) - *(qx++); + sy += *(py++) - *(qy++); + } + +/* Replace the data points in the PointSet. */ + ptr[ 0 ] = newx; + ptr[ 1 ] = newy; + oldx = astFree( oldx ); + oldy = astFree( oldy ); + } +} + +static int TestAttrib( AstObject *this_object, const char *attrib, int *status ) { +/* +* Name: +* TestAttrib + +* Purpose: +* Test if a specified attribute value is set for a Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* int TestAttrib( AstObject *this, const char *attrib, int *status ) + +* Class Membership: +* Polygon member function (over-rides the astTestAttrib protected +* method inherited from the Region class). + +* Description: +* This function returns a boolean result (0 or 1) to indicate whether +* a value has been set for one of a Polygon's attributes. + +* Parameters: +* this +* Pointer to the Polygon. +* attrib +* Pointer to a null terminated string specifying the attribute +* name. This should be in lower case with no surrounding white +* space. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* One if a value has been set, otherwise zero. + +* Notes: +* - A value of zero will be returned if this function is invoked +* with the global status set, or if it should fail for any reason. +*/ + +/* Local Variables: */ + AstPolygon *this; /* Pointer to the Polygon structure */ + int result; /* Result value to return */ + +/* Initialise. */ + result = 0; + +/* Check the global error status. */ + if ( !astOK ) return result; + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) this_object; + +/* Check the attribute name and test the appropriate attribute. */ + +/* SimpVertices. */ +/* ------------- */ + if ( !strcmp( attrib, "simpvertices" ) ) { + result = astTestSimpVertices( this ); + +/* If the attribute is not recognised, pass it on to the parent method + for further interpretation. */ + } else { + result = (*parent_testattrib)( this_object, attrib, status ); + } + +/* Return the result, */ + return result; +} + +/* +* Name: +* TraceEdge + +* Purpose: +* Find a point that is inside the required outline. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* void TraceEdge<Oper><X>( <Xtype> value, const <Xtype> array[], +* const int lbnd[ 2 ], const int ubnd[ 2 ], +* int iv0, int ix0, int iy0, int starpix, +* int full, int *status ); + +* Class Membership: +* Polygon member function + +* Description: +* This function forms a polygon enclosing the region of the data +* array specified by <Oper> and "value". If this polygon contains +* the point "(inx,iny)", then a PointSet is returned holding the +* pixel coordinates of the Polygon vertices. If the polygon +* does not contain "(inx,iny)", a NULL pointer is returned. +* +* Each vertex in the polygon corresponds to a corner of a pixel in +* the data array. + +* Parameters: +* value +* The data value defining valid pixels. +* array +* The data array. +* lbnd +* The lower pixel index bounds of the array. +* ubnd +* The upper pixel index bounds of the array. +* iv0 +* The vector index of a pixel inside the region such that the +* pixel to the right is NOT inside the region. This defines the +* start of the polygon. +* ix0 +* The X pixel index of the pixel specified by "iv0". +* inx +* The X pixel index of a point which must be inside the polygon +* for the polygon to be acceptable. +* iny +* The Y pixel index of a point which must be inside the polygon +* for the polygon to be acceptable. +* starpix +* If non-zero, the usual Starlink definition of pixel coordinate +* is used (integral values at pixel corners). Otherwise, the +* system used by other AST functions such as astResample is used +* (integral values at pixel centres). +* full +* If non-zero, the full polygon is stored. If zero, vertices in the +* middle of straight sections of the Polygon are omitted. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* A pointer to a PointSet holding the vertices of the polygon, or +* NULL if the polygon did not contain "(inx,iny)". + +* Notes: +* - <Oper> must be one of LT, LE, EQ, GE, GT, NE. + + +*/ + +/* Define a macro to implement the function for a specific data + type and operation. */ +#define MAKE_TRACEEDGE(X,Xtype,Oper,OperI) \ +static AstPointSet *TraceEdge##Oper##X( Xtype value, const Xtype array[], \ + const int lbnd[ 2 ], const int ubnd[ 2 ], \ + int iv0, int ix0, int iy0, \ + int starpix, int full, \ + int *status ){ \ +\ +/* Local Variables: */ \ + AstPointSet *result; /* Pointer to text describing oper */ \ + const Xtype *pa; /* Pointer to current valid pixel value */ \ + const Xtype *pb; /* Pointer to neigbouring valid pixel value */ \ + const Xtype *pc; /* Pointer to neigbouring valid pixel value */ \ + double *ptr[ 2 ]; /* PointSet data pointers */ \ + double *xvert; /* Pointer to array holding vertex X axis values */ \ + double *yvert; /* Pointer to array holding vertex Y axis values */ \ + double dx; /* Pertubation in X (pixels) to avoid the pixel edge */ \ + double dy; /* Pertubation in Y (pixels) to avoid the pixel edge */ \ + double xx; /* Pixel X coord at corner */ \ + double yy; /* Pixel Y coord at corner */ \ + int at; /* The pixel corner to draw to */ \ + int done; /* Have we arrived back at the start of the polygon? */ \ + int ii; /* Index of new vertex */ \ + int ix; /* X pixel index of current valid pixel */ \ + int iy; /* Y pixel index of current valid pixel */ \ + int nright; /* Overall number of right hand turns along polygon */ \ + int nvert; /* Number of vertices */ \ + int nx; /* Pixels per row */ \ +\ +/* Initialise */ \ + result = NULL; \ +\ +/* Check the global error status. */ \ + if ( !astOK ) return result; \ +\ +\ +/* Initialise pointers to arrays holding the X and Y pixel coordinates at \ + the vertices of the polygon. */ \ + xvert = NULL; \ + yvert = NULL; \ + nvert = 0; \ +\ +/* Find number of pixels in one row of the array. */ \ + nx = ( ubnd[ 0 ] - lbnd[ 0 ] + 1 ); \ +\ +/* The four corners of a pixel are numbered as follows: 0=bottom left, \ + 1=top left, 2=top right, 3=bottom right. The following algorithm moves \ + along pixel edges, from corner to corner, using the above numbering \ + scheme to identify the corners. We start the polygon by moving from the \ + bottom right to the top right corner of pixel "(ix0,iy0)". */ \ + ix = ix0; \ + iy = iy0; \ + at = 2; \ +\ +/* Store a pointer to the first good pixel value. */ \ + pa = array + ( ix - lbnd[ 0 ] ) + nx*( iy - lbnd[ 1 ] ) ; \ +\ +/* We count the number of times the polygon turns to the right compared \ + to the left. Initialise it to zero. */ \ + nright = 0; \ +\ +/* Loop round tracing out the polygon until we arrive back at the \ + beginning. The Polygon class requires that the inside of the polygon \ + is to the left as we move round the polygon in an anti-clockwise \ + direction. So at each corner, we attempt to move to the next \ + anti-clockwise good pixel corner. */ \ + done = 0; \ + while( !done ) { \ +\ +/* If we have arrived at the bottom left corner of the good pixel, we must \ + have come from the top left corner since all movements around a pixel \ + must be anti-clockwise. */ \ + if( at == 0 ) { \ +\ +/* Note the pixel coordinates at the bottom left corner of the current \ + pixel. */ \ + if( starpix ) { \ + xx = ix - 1.0; \ + yy = iy - 1.0; \ + } else { \ + xx = ix - 0.5; \ + yy = iy - 0.5; \ + } \ +\ +/* Get a pointer to lower left pixel value */ \ + pb = pa - nx - 1; \ +\ +/* Get a pointer to lower mid pixel value. */ \ + pc = pb + 1; \ +\ +/* If the lower left pixel is within the array and meets the validity \ + requirements, move to the left along its top edge. */ \ + if( iy > lbnd[ 1 ] && ix > lbnd[ 0 ] && ISVALID(*pb,OperI,value) ) { \ + nright++; \ + pa = pb; \ + at = 1; \ + ix--; \ + iy--; \ + dx = DELTA; \ + dy = -DELTA; \ +\ +/* Otherwise, if lower mid pixel is good, move down its left edge. */ \ + } else if( iy > lbnd[ 1 ] && ISVALID(*pc,OperI,value) ) { \ + pa = pc; \ + at = 0; \ + iy--; \ + dx = DELTA; \ + dy = 0.0; \ +\ +/* Otherwise, move to the right along the bottom edge of the current pixel. */ \ + } else { \ + nright--; \ + at = 3; \ + dx = DELTA; \ + dy = DELTA; \ + } \ +\ +/* If the polygon bends at this point, or if we will be smoothing the \ + polygon, append the pixel coordinates at this pixel corner to the \ + polygon. */ \ + if( full || pa != pc ) ADD( xx, yy ); \ +\ +/* If we have arrived at the top left corner of the good pixel, we must \ + have come from the top right corner. */ \ + } else if( at == 1 ) { \ +\ +/* Note the pixel coordinates at the top left corner of the current \ + pixel. */ \ + if( starpix ) { \ + xx = ix - 1.0; \ + yy = iy; \ + } else { \ + xx = ix - 0.5; \ + yy = iy + 0.5; \ + } \ +\ +/* Get a pointer to upper left pixel value */ \ + pb = pa + nx - 1; \ +\ +/* Get a pointer to mid left pixel value. */ \ + pc = pa - 1; \ +\ +/* If upper left pixel is good, move up its left edge. */ \ + if( iy < ubnd[ 1 ] && ix > lbnd[ 0 ] && ISVALID(*pb,OperI,value) ) { \ + nright++; \ + pa = pb; \ + at = 2; \ + ix--; \ + iy++; \ + dx = -DELTA; \ + dy = -DELTA; \ +\ +/* Otherwise, if left mid pixel is good, move left along its top edge. */ \ + } else if( ix > lbnd[ 0 ] && ISVALID(*pc,OperI,value) ) { \ + pa = pc; \ + at = 1; \ + ix--; \ + dx = 0.0; \ + dy = -DELTA; \ +\ +/* Otherwise, move down the left edge of the current pixel. */ \ + } else { \ + nright--; \ + at = 0; \ + dx = DELTA; \ + dy = -DELTA; \ + } \ +\ +/* If the polygon bends at this point, or if we will be smoothing the \ + polygon, append the pixel coordinates at this pixel corner to the \ + polygon. */ \ + if( full || pa != pc ) ADD( xx, yy ); \ +\ +/* If we have arrived at the top right corner of the good pixel, we must \ + have come from the bottom right corner. */ \ + } else if( at == 2 ) { \ +\ +/* Note the pixel coordinates at the top right corner of the current \ + pixel. */ \ + if( starpix ) { \ + xx = ix; \ + yy = iy; \ + } else { \ + xx = ix + 0.5; \ + yy = iy + 0.5; \ + } \ +\ +/* Pointer to upper right pixel value */ \ + pb = pa + nx + 1; \ +\ +/* Pointer to top mid pixel value. */ \ + pc = pa + nx; \ +\ +/* If upper right pixel is good, move right along its bottom edge. */ \ + if( iy < ubnd[ 1 ] && ix < ubnd[ 0 ] && ISVALID(*pb,OperI,value) ){ \ + nright++; \ + pa = pb; \ + at = 3; \ + ix++; \ + iy++; \ + dx = -DELTA; \ + dy = DELTA; \ +\ +/* Otherwise, if upper mid pixel is good, move up its right edge. */ \ + } else if( iy < ubnd[ 1 ] && ISVALID(*pc,OperI,value) ) { \ + pa = pc; \ + at = 2; \ + iy++; \ + dx = -DELTA; \ + dy = 0.0; \ +\ +/* Otherwise, move left along the top edge of the current pixel. */ \ + } else { \ + nright--; \ + at = 1; \ + dx = -DELTA; \ + dy = -DELTA; \ + } \ +\ +/* If the polygon bends at this point, or if we will be smoothing the \ + polygon, append the pixel coordinates at this pixel corner to the \ + polygon. */ \ + if( full || pa != pc ) ADD( xx, yy ); \ +\ +/* Arrived at bottom right corner of good pixel from lower left. */ \ + } else { \ +\ +/* Note the pixel coordinates at the bottom right corner of the current \ + pixel. */ \ + if( starpix ) { \ + xx = ix; \ + yy = iy - 1.0; \ + } else { \ + xx = ix + 0.5; \ + yy = iy - 0.5; \ + } \ +\ +/* Pointer to lower right pixel value */ \ + pb = pa - ( nx - 1 ); \ +\ +/* Pointer to mid right pixel value. */ \ + pc = pa + 1; \ +\ +/* If lower right pixel is good, move down its left edge. */ \ + if( iy > lbnd[ 1 ] && ix < ubnd[ 0 ] && ISVALID(*pb,OperI,value) ) { \ + nright++; \ + pa = pb; \ + at = 0; \ + ix++; \ + iy--; \ + dx = DELTA; \ + dy = DELTA; \ +\ +/* Otherwise, if right mid pixel is good, move right along its lower edge. */ \ + } else if( ix < ubnd[ 0 ] && ISVALID(*pc,OperI,value) ) { \ + pa = pc; \ + at = 3; \ + ix++; \ + dx = 0.0; \ + dy = DELTA; \ +\ +/* Otherwise, move up the right edge of the current pixel. */ \ + } else { \ + nright--; \ + at = 2; \ + dx = -DELTA; \ + dy = DELTA; \ + } \ +\ +/* If the polygon bends at this point, or if we will be smoothing the \ + polygon, append the pixel coordinates at this pixel corner to the \ + polygon. */ \ + if( full || pa != pc ) ADD( xx, yy ); \ + } \ +\ +/* If we have arrived back at the start, break out of the loop. */ \ + if( ix == ix0 && iy == iy0 && at == 2 ) done = 1; \ + } \ +\ +/* If we have circled round to the right, the polygon will not enclosed \ + the specified position, so free resources and return a NULL pointer. */ \ + if( nright > 0 ) { \ + xvert = astFree( xvert ); \ + yvert = astFree( yvert ); \ +\ +/* If we have circled round to the left, the polygon will enclose \ + the specified position, so create and return a PointSet. */ \ + } else { \ + result = astPointSet( nvert, 2, " ", status ); \ + ptr[ 0 ] = xvert; \ + ptr[ 1 ] = yvert; \ + astSetPoints( result, ptr ); \ + } \ +\ +/* Annul the returned PointSet if anythign went wrong. */ \ + if( !astOK && result ) result = astAnnul( result ); \ +\ +/* Return the PointSet pointer. */ \ + return result; \ +} + +/* Define a macro to add a vertex position to dynamically allocated + arrays of X and Y positions. We offset the supplied position by + a small fraction of a pixel towards the centre of hte polygon to + avoid placing vertices exactly on the edge, which may cause problems + later for pixels that are on the edge of an area of bad pixel. */ +#define ADD(X,Y) {\ + ii = nvert++; \ + xvert = (double *) astGrow( xvert, nvert, sizeof( double ) ); \ + yvert = (double *) astGrow( yvert, nvert, sizeof( double ) ); \ + if( astOK ) { \ + xvert[ ii ] = (X+dx); \ + yvert[ ii ] = (Y+dy); \ + } \ +} + +/* Define a macro that uses the above macro to to create implementations + of TraceEdge for all operations. */ +#define MAKEALL_TRACEEDGE(X,Xtype) \ +MAKE_TRACEEDGE(X,Xtype,LT,AST__LT) \ +MAKE_TRACEEDGE(X,Xtype,LE,AST__LE) \ +MAKE_TRACEEDGE(X,Xtype,EQ,AST__EQ) \ +MAKE_TRACEEDGE(X,Xtype,NE,AST__NE) \ +MAKE_TRACEEDGE(X,Xtype,GE,AST__GE) \ +MAKE_TRACEEDGE(X,Xtype,GT,AST__GT) + +/* Expand the above macro to generate a function for each required + data type and operation. */ +#if HAVE_LONG_DOUBLE /* Not normally implemented */ +MAKEALL_TRACEEDGE(LD,long double) +#endif +MAKEALL_TRACEEDGE(D,double) +MAKEALL_TRACEEDGE(L,long int) +MAKEALL_TRACEEDGE(UL,unsigned long int) +MAKEALL_TRACEEDGE(I,int) +MAKEALL_TRACEEDGE(UI,unsigned int) +MAKEALL_TRACEEDGE(S,short int) +MAKEALL_TRACEEDGE(US,unsigned short int) +MAKEALL_TRACEEDGE(B,signed char) +MAKEALL_TRACEEDGE(UB,unsigned char) +MAKEALL_TRACEEDGE(F,float) + +/* Undefine the macros. */ +#undef MAKE_TRACEEDGE +#undef MAKEALL_TRACEEDGE + +static AstPointSet *Transform( AstMapping *this_mapping, AstPointSet *in, + int forward, AstPointSet *out, int *status ) { +/* +* Name: +* Transform + +* Purpose: +* Apply a Polygon to transform a set of points. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* AstPointSet *Transform( AstMapping *this, AstPointSet *in, +* int forward, AstPointSet *out, int *status ) + +* Class Membership: +* Polygon member function (over-rides the astTransform protected +* method inherited from the Region class). + +* Description: +* This function takes a Polygon and a set of points encapsulated in a +* PointSet and transforms the points by setting axis values to +* AST__BAD for all points which are outside the region. Points inside +* the region are copied unchanged from input to output. + +* Parameters: +* this +* Pointer to the Polygon. +* in +* Pointer to the PointSet holding the input coordinate data. +* forward +* A non-zero value indicates that the forward coordinate transformation +* should be applied, while a zero value requests the inverse +* transformation. +* out +* Pointer to a PointSet which will hold the transformed (output) +* coordinate values. A NULL value may also be given, in which case a +* new PointSet will be created by this function. +* status +* Pointer to the inherited status variable. + +* Returned Value: +* Pointer to the output (possibly new) PointSet. + +* Notes: +* - The forward and inverse transformations are identical for a +* Region. +* - A null pointer will be returned if this function is invoked with the +* global error status set, or if it should fail for any reason. +* - The number of coordinate values per point in the input PointSet must +* match the number of axes in the Frame represented by the Polygon. +* - If an output PointSet is supplied, it must have space for sufficient +* number of points and coordinate values per point to accommodate the +* result. Any excess space will be ignored. +*/ + +/* Local Variables: */ + AstFrame *frm; /* Pointer to base Frame in FrameSet */ + AstLineDef *a; /* Line from inside point to test point */ + AstLineDef *b; /* Polygon edge */ + AstPointSet *in_base; /* PointSet holding base Frame input positions*/ + AstPointSet *result; /* Pointer to output PointSet */ + AstPolygon *this; /* Pointer to Polygon */ + double **ptr_in; /* Pointer to input base Frame coordinate data */ + double **ptr_out; /* Pointer to output current Frame coordinate data */ + double *px; /* Pointer to array of first axis values */ + double *py; /* Pointer to array of second axis values */ + double p[ 2 ]; /* Current test position */ + int closed; /* Is the boundary part of the Region? */ + int i; /* Edge index */ + int icoord; /* Coordinate index */ + int in_region; /* Is the point inside the Region? */ + int ncoord_out; /* No. of current Frame axes */ + int ncross; /* Number of crossings */ + int neg; /* Has the Region been negated? */ + int npoint; /* No. of input points */ + int nv; /* No. of vertices */ + int point; /* Loop counter for input points */ + int pos; /* Is test position in, on, or outside boundary? */ + +/* Check the global error status. */ + if ( !astOK ) return NULL; + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) this_mapping; + +/* Apply the parent mapping using the stored pointer to the Transform member + function inherited from the parent Region class. This function validates + all arguments and generates an output PointSet if necessary, + containing a copy of the input PointSet. */ + result = (*parent_transform)( this_mapping, in, forward, out, status ); + +/* Get the number of points to be transformed. */ + npoint = astGetNpoint( result ); + +/* Get a pointer to the output axis values. */ + ptr_out = astGetPoints( result ); + +/* Find the number of axes in the current Frame. This need not be 2 (the + number of axes in the *base* Frame must be 2 however). */ + ncoord_out = astGetNcoord( result ); + +/* We will now extend the parent astTransform method by performing the + calculations needed to generate the output coordinate values. */ + +/* First use the encapsulated FrameSet to transform the supplied positions + from the current Frame in the encapsulated FrameSet (the Frame + represented by the Region), to the base Frame (the Frame in which the + Region is defined). This call also returns a pointer to the base Frame + of the encapsulated FrameSet. Note, the returned pointer may be a + clone of the "in" pointer, and so we must be carefull not to modify the + contents of the returned PointSet. */ + in_base = astRegTransform( this, in, 0, NULL, &frm ); + ptr_in = astGetPoints( in_base ); + +/* Get the number of vertices in the polygon. */ + nv = astGetNpoint( ((AstRegion *) this)->points ); + +/* See if the boundary is part of the Region. */ + closed = astGetClosed( this ); + +/* See if the Region has been negated. */ + neg = astGetNegated( this ); + +/* Perform coordinate arithmetic. */ +/* ------------------------------ */ + if ( astOK ) { + px = ptr_in[ 0 ]; + py = ptr_in[ 1 ]; + +/* Loop round each supplied point in the base Frame of the polygon. */ + for ( point = 0; point < npoint; point++, px++, py++ ) { + +/* If the input point is bad, indicate that bad output values should be + returned. */ + if( *px == AST__BAD || *py == AST__BAD ) { + in_region = 0; + +/* Otherwise, we first determine if the point is inside, outside, or on, + the Polygon boundary. Initialially it is unknown. */ + } else { + +/* Ensure cached information is available.*/ + Cache( this, status ); + +/* Create a definition of the line from a point which is inside the + polygon to the supplied point. This is a structure which includes + cached intermediate information which can be used to speed up + subsequent calculations. */ + p[ 0 ] = *px; + p[ 1 ] = *py; + a = astLineDef( frm, this->in, p ); + +/* We now determine the number of times this line crosses the polygon + boundary. Initialise the number of crossings to zero. */ + ncross = 0; + pos = UNKNOWN; + +/* Loop rouind all edges of the polygon. */ + for( i = 0; i < nv; i++ ) { + b = this->edges[ i ]; + +/* If this point is on the current edge, then we need do no more checks + since we know it is either inside or outside the polygon (depending on + whether the polygon is closed or not). */ + if( astLineContains( frm, b, 0, p ) ) { + pos = ON; + break; + +/* Otherwise, see if the two lines cross within their extent. If so, + increment the number of crossings. */ + } else if( astLineCrossing( frm, b, a, NULL ) ) { + ncross++; + } + } + +/* Free resources */ + a = astFree( a ); + +/* If the position is not on the boundary, it is inside the boundary if + the number of crossings is even, and outside otherwise. */ + if( pos == UNKNOWN ) pos = ( ncross % 2 == 0 )? IN : OUT; + +/* Whether the point is in the Region depends on whether the point is + inside the polygon boundary, whether the Polygon has been negated, and + whether the polygon is closed. */ + if( neg ) { + if( pos == IN ) { + in_region = 0; + } else if( pos == OUT ) { + in_region = 1; + } else if( closed ) { + in_region = 1; + } else { + in_region = 0; + } + + } else { + if( pos == IN ) { + in_region = 1; + } else if( pos == OUT ) { + in_region = 0; + } else if( closed ) { + in_region = 1; + } else { + in_region = 0; + } + } + } + +/* If the point is not inside the Region, store bad output values. */ + if( !in_region ) { + for ( icoord = 0; icoord < ncoord_out; icoord++ ) { + ptr_out[ icoord ][ point ] = AST__BAD; + } + } + } + } + +/* Free resources */ + in_base = astAnnul( in_base ); + frm = astAnnul( frm ); + +/* Annul the result if an error has occurred. */ + if( !astOK ) result = astAnnul( result ); + +/* Return a pointer to the output PointSet. */ + return result; +} + +/* Functions which access class attributes. */ +/* ---------------------------------------- */ +/* Implement member functions to access the attributes associated with + this class using the macros defined for this purpose in the + "object.h" file. For a description of each attribute, see the class + interface (in the associated .h file). */ + +/* +*att++ +* Name: +* SimpVertices + +* Purpose: +* Simplify a Polygon by transforming its vertices? + +* Type: +* Public attribute. + +* Synopsis: +* Integer (boolean). + +* Description: +* This attribute controls the behaviour of the +c astSimplify +f AST_SIMPLIFY +* method when applied to a Polygon. The simplified Polygon is created +* by transforming the vertices from the Frame in which the Polygon +* was originally defined into the Frame currently represented by the +* Polygon. If SimpVertices is non-zero (the default) then this +* simplified Polygon is returned without further checks. If SimpVertices +* is zero, a check is made that the edges of the new Polygon do not +* depart significantly from the edges of the original Polygon (as +* determined by the uncertainty associated with the Polygon). This +* could occur, for instance, if the Mapping frrm the original to the +* current Frame is highly non-linear. If this check fails, the +* original unsimplified Polygon is returned without change. + +* Applicability: +* Polygon +* All Polygons have this attribute. + +*att-- +*/ +astMAKE_CLEAR(Polygon,SimpVertices,simp_vertices,-INT_MAX) +astMAKE_GET(Polygon,SimpVertices,int,0,( ( this->simp_vertices != -INT_MAX ) ? + this->simp_vertices : 1 )) +astMAKE_SET(Polygon,SimpVertices,int,simp_vertices,( value != 0 )) +astMAKE_TEST(Polygon,SimpVertices,( this->simp_vertices != -INT_MAX )) + +/* Copy constructor. */ +/* ----------------- */ +static void Copy( const AstObject *objin, AstObject *objout, int *status ) { +/* +* Name: +* Copy + +* Purpose: +* Copy constructor for Polygon objects. + +* Type: +* Private function. + +* Synopsis: +* void Copy( const AstObject *objin, AstObject *objout, int *status ) + +* Description: +* This function implements the copy constructor for Polygon objects. + +* Parameters: +* objin +* Pointer to the object to be copied. +* objout +* Pointer to the object being constructed. +* status +* Pointer to the inherited status variable. + +* Notes: +* - This constructor makes a deep copy. +*/ + +/* Local Variables: */ + AstPolygon *out; /* Pointer to output Polygon */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Obtain pointers to the output Polygon. */ + out = (AstPolygon *) objout; + +/* For safety, first clear any references to the input memory from + the output Polygon. */ + out->edges = NULL; + out->startsat = NULL; + +/* Indicate cached information needs nre-calculating. */ + astResetCache( (AstPolygon *) out ); +} + + +/* Destructor. */ +/* ----------- */ +static void Delete( AstObject *obj, int *status ) { +/* +* Name: +* Delete + +* Purpose: +* Destructor for Polygon objects. + +* Type: +* Private function. + +* Synopsis: +* void Delete( AstObject *obj, int *status ) + +* Description: +* This function implements the destructor for Polygon objects. + +* Parameters: +* obj +* Pointer to the object to be deleted. +* status +* Pointer to the inherited status variable. + +* Notes: +* This function attempts to execute even if the global error status is +* set. +*/ + +/* Local Variables: */ + AstPointSet *ps; /* Pointer to PointSet inside Region */ + AstPolygon *this; /* Pointer to Polygon */ + int i; /* Index of vertex */ + int istat; /* Original AST error status */ + int nv; /* Number of vertices */ + int rep; /* Original error reporting state */ + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) obj; + +/* Annul all resources. */ + ps = ((AstRegion *) this)->points; + if( this->edges && ps ) { + +/* Ensure we get a value for "nv" even if an error has occurred. */ + istat = astStatus; + astClearStatus; + rep = astReporting( 0 ); + + nv = astGetNpoint( ps ); + + astSetStatus( istat ); + astReporting( rep ); + +/* Free the structures holding the edge information. */ + for( i = 0; i < nv; i++ ) { + this->edges[ i ] = astFree( this->edges[ i ] ); + } + } + + this->edges = astFree( this->edges ); + this->startsat = astFree( this->startsat ); +} + +/* Dump function. */ +/* -------------- */ +static void Dump( AstObject *this_object, AstChannel *channel, int *status ) { +/* +* Name: +* Dump + +* Purpose: +* Dump function for Polygon objects. + +* Type: +* Private function. + +* Synopsis: +* void Dump( AstObject *this, AstChannel *channel, int *status ) + +* Description: +* This function implements the Dump function which writes out data +* for the Polygon class to an output Channel. + +* Parameters: +* this +* Pointer to the Polygon whose data are being written. +* channel +* Pointer to the Channel to which the data are being written. +* status +* Pointer to the inherited status variable. +*/ + +/* Local Variables: */ + AstPolygon *this; /* Pointer to the Polygon structure */ + int ival; /* Integer attribute value */ + int set; /* Attribute value set? */ + +/* Check the global error status. */ + if ( !astOK ) return; + +/* Obtain a pointer to the Polygon structure. */ + this = (AstPolygon *) this_object; + +/* Write out values representing the instance variables for the + Polygon class. Accompany these with appropriate comment strings, + possibly depending on the values being written.*/ + +/* In the case of attributes, we first use the appropriate (private) + Test... member function to see if they are set. If so, we then use + the (private) Get... function to obtain the value to be written + out. + + For attributes which are not set, we use the astGet... method to + obtain the value instead. This will supply a default value + (possibly provided by a derived class which over-rides this method) + which is more useful to a human reader as it corresponds to the + actual default attribute value. Since "set" will be zero, these + values are for information only and will not be read back. */ + +/* SimpVertices. */ +/* ------------ */ +/* Write out the forward-inverse simplification flag. */ + set = TestSimpVertices( this, status ); + ival = set ? GetSimpVertices( this, status ) : astGetSimpVertices( this ); + astWriteInt( channel, "SimpVT", set, 0, ival, "Simplify by transforming vertices?" ); + +/* A flag indicating the convention used for determining the interior of + the polygon. A zero value indicates that the old AST system is in + use (inside to the left when moving anti-clockwise round the vertices + as viewed from the outside of the celestial sphere). A non-zero value + indicates the STC system is in use (inside to the left when moving + anti-clockwise round the vertices as viewed from the inside of the + celestial sphere). AST currently uses the STC system. */ + astWriteInt( channel, "Order", 1, 0, 1, "Polygon uses STC vertex order convention" ); +} + +/* Standard class functions. */ +/* ========================= */ +/* Implement the astIsAPolygon and astCheckPolygon functions using the macros + defined for this purpose in the "object.h" header file. */ +astMAKE_ISA(Polygon,Region) +astMAKE_CHECK(Polygon) + +AstPolygon *astPolygon_( void *frame_void, int npnt, int dim, + const double *points, AstRegion *unc, + const char *options, int *status, ...) { +/* +*++ +* Name: +c astPolygon +f AST_POLYGON + +* Purpose: +* Create a Polygon. + +* Type: +* Public function. + +* Synopsis: +c #include "polygon.h" +c AstPolygon *astPolygon( AstFrame *frame, int npnt, int dim, +c const double *points, AstRegion *unc, +c const char *options, ... ) +f RESULT = AST_POLYGON( FRAME, NPNT, DIM, POINTS, UNC, OPTIONS, STATUS ) + +* Class Membership: +* Polygon constructor. + +* Description: +* This function creates a new Polygon object and optionally initialises +* its attributes. +* +* The Polygon class implements a polygonal area, defined by a +* collection of vertices, within a 2-dimensional Frame. The vertices +* are connected together by geodesic curves within the encapsulated Frame. +* For instance, if the encapsulated Frame is a simple Frame then the +* geodesics will be straight lines, but if the Frame is a SkyFrame then +* the geodesics will be great circles. Note, the vertices must be +* supplied in an order such that the inside of the polygon is to the +* left of the boundary as the vertices are traversed. Supplying them +* in the reverse order will effectively negate the polygon. +* +* Within a SkyFrame, neighbouring vertices are always joined using the +* shortest path. Thus if an edge of 180 degrees or more in length is +* required, it should be split into section each of which is less +* than 180 degrees. The closed path joining all the vertices in order +* will divide the celestial sphere into two disjoint regions. The +* inside of the polygon is the region which is circled in an +* anti-clockwise manner (when viewed from the inside of the celestial +* sphere) when moving through the list of vertices in the order in +* which they were supplied when the Polygon was created (i.e. the +* inside is to the left of the boundary when moving through the +* vertices in the order supplied). + +* Parameters: +c frame +f FRAME = INTEGER (Given) +* A pointer to the Frame in which the region is defined. It must +* have exactly 2 axes. A deep copy is taken of the supplied Frame. +* This means that any subsequent changes made to the Frame using the +* supplied pointer will have no effect the Region. +c npnt +f NPNT = INTEGER (Given) +* The number of points in the Region. +c dim +f DIM = INTEGER (Given) +c The number of elements along the second dimension of the "points" +f The number of elements along the first dimension of the POINTS +* array (which contains the point coordinates). This value is +* required so that the coordinate values can be correctly +* located if they do not entirely fill this array. The value +c given should not be less than "npnt". +f given should not be less than NPNT. +c points +f POINTS( DIM, 2 ) = DOUBLE PRECISION (Given) +c The address of the first element of a 2-dimensional array of +c shape "[2][dim]" giving the physical coordinates of the vertices. +c These should be stored such that the value of coordinate +c number "coord" for point number "pnt" is found in element +c "in[coord][pnt]". +f A 2-dimensional array giving the physical coordinates of the +f vertices. These should be stored such that the value of coordinate +f number COORD for point number PNT is found in element IN(PNT,COORD). +c unc +f UNC = INTEGER (Given) +* An optional pointer to an existing Region which specifies the +* uncertainties associated with the boundary of the Polygon being created. +* The uncertainty in any point on the boundary of the Polygon is found by +* shifting the supplied "uncertainty" Region so that it is centred at +* the boundary point being considered. The area covered by the +* shifted uncertainty Region then represents the uncertainty in the +* boundary position. The uncertainty is assumed to be the same for +* all points. +* +* If supplied, the uncertainty Region must be of a class for which +* all instances are centro-symetric (e.g. Box, Circle, Ellipse, etc.) +* or be a Prism containing centro-symetric component Regions. A deep +* copy of the supplied Region will be taken, so subsequent changes to +* the uncertainty Region using the supplied pointer will have no +* effect on the created Polygon. Alternatively, +f a null Object pointer (AST__NULL) +c a NULL Object pointer +* may be supplied, in which case a default uncertainty is used +* equivalent to a box 1.0E-6 of the size of the Polygon being created. +* +* The uncertainty Region has two uses: 1) when the +c astOverlap +f AST_OVERLAP +* function compares two Regions for equality the uncertainty +* Region is used to determine the tolerance on the comparison, and 2) +* when a Region is mapped into a different coordinate system and +* subsequently simplified (using +c astSimplify), +f AST_SIMPLIFY), +* the uncertainties are used to determine if the transformed boundary +* can be accurately represented by a specific shape of Region. +c options +f OPTIONS = CHARACTER * ( * ) (Given) +c Pointer to a null-terminated string containing an optional +c comma-separated list of attribute assignments to be used for +c initialising the new Polygon. The syntax used is identical to +c that for the astSet function and may include "printf" format +c specifiers identified by "%" symbols in the normal way. +f A character string containing an optional comma-separated +f list of attribute assignments to be used for initialising the +f new Polygon. The syntax used is identical to that for the +f AST_SET routine. +c ... +c If the "options" string contains "%" format specifiers, then +c an optional list of additional arguments may follow it in +c order to supply values to be substituted for these +c specifiers. The rules for supplying these are identical to +c those for the astSet function (and for the C "printf" +c function). +f STATUS = INTEGER (Given and Returned) +f The global status. + +* Returned Value: +c astPolygon() +f AST_POLYGON = INTEGER +* A pointer to the new Polygon. + +* Notes: +* - A null Object pointer (AST__NULL) will be returned if this +c function is invoked with the AST error status set, or if it +f function is invoked with STATUS set to an error value, or if it +* should fail for any reason. + +* Status Handling: +* The protected interface to this function includes an extra +* parameter at the end of the parameter list descirbed above. This +* parameter is a pointer to the integer inherited status +* variable: "int *status". + +*-- +*/ + +/* Local Variables: */ + astDECLARE_GLOBALS /* Pointer to thread-specific global data */ + AstFrame *frame; /* Pointer to Frame structure */ + AstPolygon *new; /* Pointer to new Polygon */ + va_list args; /* Variable argument list */ + +/* Get a pointer to the thread specific global data structure. */ + astGET_GLOBALS(NULL); + +/* Check the global status. */ + if ( !astOK ) return NULL; + +/* Obtain and validate a pointer to the supplied Frame structure. */ + frame = astCheckFrame( frame_void ); + +/* Initialise the Polygon, allocating memory and initialising the + virtual function table as well if necessary. */ + new = astInitPolygon( NULL, sizeof( AstPolygon ), !class_init, + &class_vtab, "Polygon", frame, npnt, + dim, points, unc ); + +/* If successful, note that the virtual function table has been + initialised. */ + if ( astOK ) { + class_init = 1; + +/* Obtain the variable argument list and pass it along with the options string + to the astVSet method to initialise the new Polygon's attributes. */ + va_start( args, status ); + astVSet( new, options, NULL, args ); + va_end( args ); + +/* If an error occurred, clean up by deleting the new object. */ + if ( !astOK ) new = astDelete( new ); + } + +/* Return a pointer to the new Polygon. */ + return new; +} + +AstPolygon *astPolygonId_( void *frame_void, int npnt, int dim, + const double *points, void *unc_void, + const char *options, ... ) { +/* +* Name: +* astPolygonId_ + +* Purpose: +* Create a Polygon. + +* Type: +* Private function. + +* Synopsis: +* #include "polygon.h" +* AstPolygon *astPolygonId_( void *frame_void, int npnt, +* int dim, const double *points, void *unc_void, +* const char *options, ... ) + +* Class Membership: +* Polygon constructor. + +* Description: +* This function implements the external (public) interface to the +* astPolygon constructor function. It returns an ID value (instead +* of a true C pointer) to external users, and must be provided +* because astPolygon_ has a variable argument list which cannot be +* encapsulated in a macro (where this conversion would otherwise +* occur). +* +* The variable argument list also prevents this function from +* invoking astPolygon_ directly, so it must be a re-implementation +* of it in all respects, except for the final conversion of the +* result to an ID value. + +* Parameters: +* As for astPolygon_. + +* Returned Value: +* The ID value associated with the new Polygon. +*/ + +/* Local Variables: */ + astDECLARE_GLOBALS /* Pointer to thread-specific global data */ + AstFrame *frame; /* Pointer to Frame structure */ + AstPolygon *new; /* Pointer to new Polygon */ + AstRegion *unc; /* Pointer to Region structure */ + va_list args; /* Variable argument list */ + + int *status; /* Get a pointer to the thread specific global data structure. */ + astGET_GLOBALS(NULL); + +/* Get a pointer to the inherited status value. */ + status = astGetStatusPtr; + +/* Check the global status. */ + if ( !astOK ) return NULL; + +/* Obtain a Frame pointer from the supplied ID and validate the + pointer to ensure it identifies a valid Frame. */ + frame = astVerifyFrame( astMakePointer( frame_void ) ); + +/* Obtain a Region pointer from the supplied "unc" ID and validate the + pointer to ensure it identifies a valid Region . */ + unc = unc_void ? astVerifyRegion( astMakePointer( unc_void ) ) : NULL; + +/* Initialise the Polygon, allocating memory and initialising the + virtual function table as well if necessary. */ + new = astInitPolygon( NULL, sizeof( AstPolygon ), !class_init, + &class_vtab, "Polygon", frame, npnt, dim, + points, unc ); + +/* If successful, note that the virtual function table has been + initialised. */ + if ( astOK ) { + class_init = 1; + +/* Obtain the variable argument list and pass it along with the options string + to the astVSet method to initialise the new Polygon's attributes. */ + va_start( args, options ); + astVSet( new, options, NULL, args ); + va_end( args ); + +/* If an error occurred, clean up by deleting the new object. */ + if ( !astOK ) new = astDelete( new ); + } + +/* Return an ID value for the new Polygon. */ + return astMakeId( new ); +} + + +AstPolygon *astInitPolygon_( void *mem, size_t size, int init, AstPolygonVtab *vtab, + const char *name, AstFrame *frame, int npnt, + int dim, const double *points, AstRegion *unc, int *status ) { +/* +*+ +* Name: +* astInitPolygon + +* Purpose: +* Initialise a Polygon. + +* Type: +* Protected function. + +* Synopsis: +* #include "polygon.h" +* AstPolygon *astInitPolygon( void *mem, size_t size, int init, AstPolygonVtab *vtab, +* const char *name, AstFrame *frame, int npnt, +* int dim, const double *points, AstRegion *unc ) + +* Class Membership: +* Polygon initialiser. + +* Description: +* This function is provided for use by class implementations to initialise +* a new Polygon object. It allocates memory (if necessary) to accommodate +* the Polygon plus any additional data associated with the derived class. +* It then initialises a Polygon structure at the start of this memory. If +* the "init" flag is set, it also initialises the contents of a virtual +* function table for a Polygon at the start of the memory passed via the +* "vtab" parameter. + +* Parameters: +* mem +* A pointer to the memory in which the Polygon is to be initialised. +* This must be of sufficient size to accommodate the Polygon data +* (sizeof(Polygon)) plus any data used by the derived class. If a value +* of NULL is given, this function will allocate the memory itself using +* the "size" parameter to determine its size. +* size +* The amount of memory used by the Polygon (plus derived class data). +* This will be used to allocate memory if a value of NULL is given for +* the "mem" parameter. This value is also stored in the Polygon +* structure, so a valid value must be supplied even if not required for +* allocating memory. +* init +* A logical flag indicating if the Polygon's virtual function table is +* to be initialised. If this value is non-zero, the virtual function +* table will be initialised by this function. +* vtab +* Pointer to the start of the virtual function table to be associated +* with the new Polygon. +* name +* Pointer to a constant null-terminated character string which contains +* the name of the class to which the new object belongs (it is this +* pointer value that will subsequently be returned by the astGetClass +* method). +* frame +* A pointer to the Frame in which the region is defined. +* npnt +* The number of points in the Region. +* dim +* The number of elements along the second dimension of the "points" +* array (which contains the point coordinates). This value is +* required so that the coordinate values can be correctly +* located if they do not entirely fill this array. The value +* given should not be less than "npnt". +* points +* The address of the first element of a 2-dimensional array of +* shape "[2][dim]" giving the physical coordinates of the +* points. These should be stored such that the value of coordinate +* number "coord" for point number "pnt" is found in element +* "in[coord][pnt]". +* unc +* A pointer to a Region which specifies the uncertainty in the +* supplied positions (all points in the new Polygon being +* initialised are assumed to have the same uncertainty). A NULL +* pointer can be supplied, in which case default uncertainties equal +* to 1.0E-6 of the dimensions of the new Polygon's bounding box are +* used. If an uncertainty Region is supplied, it must be either a Box, +* a Circle or an Ellipse, and its encapsulated Frame must be related +* to the Frame supplied for parameter "frame" (i.e. astConvert +* should be able to find a Mapping between them). Two positions +* the "frame" Frame are considered to be co-incident if their +* uncertainty Regions overlap. The centre of the supplied +* uncertainty Region is immaterial since it will be re-centred on the +* point being tested before use. A deep copy is taken of the supplied +* Region. + +* Returned Value: +* A pointer to the new Polygon. + +* Notes: +* - A null pointer will be returned if this function is invoked with the +* global error status set, or if it should fail for any reason. +*- +*/ + +/* Local Variables: */ + AstPolygon *new; /* Pointer to new Polygon */ + AstPointSet *pset; /* Pointer to PointSet holding points */ + const double *q; /* Pointer to next supplied axis value */ + double **ptr; /* Pointer to data in pset */ + double *p; /* Pointer to next PointSet axis value */ + int i; /* Axis index */ + int j; /* Point index */ + int nin; /* No. of axes */ + +/* Check the global status. */ + if ( !astOK ) return NULL; + +/* If necessary, initialise the virtual function table. */ + if ( init ) astInitPolygonVtab( vtab, name ); + +/* Initialise. */ + new = NULL; + +/* Check the number of axis values per position is correct. */ + nin = astGetNaxes( frame ); + if( nin != 2 ) { + astError( AST__BADIN, "astInitPolygon(%s): The supplied %s has %d " + "axes - polygons must have exactly 2 axes.", status, name, + astGetClass( frame ), nin ); + +/* If so create a PointSet and store the supplied points in it. Check + none are bad. */ + } else { + pset = astPointSet( npnt, 2, "", status ); + ptr = astGetPoints( pset ); + for( i = 0; i < 2 && astOK; i++ ) { + p = ptr[ i ]; + q = points + i*dim; + for( j = 0; j < npnt; j++ ) { + if( (*(p++) = *(q++)) == AST__BAD ) { + astError( AST__BADIN, "astInitPolygon(%s): One or more " + "bad axis values supplied for the vertex " + "number %d.", status, name, j + 1 ); + break; + } + } + } + +/* Initialise a Region structure (the parent class) as the first component + within the Polygon structure, allocating memory if necessary. */ + new = (AstPolygon *) astInitRegion( mem, size, 0, (AstRegionVtab *) vtab, + name, frame, pset, unc ); + if ( astOK ) { + +/* Initialise the Polygon data. */ +/* ------------------------------ */ + new->lbnd[ 0 ] = AST__BAD; + new->ubnd[ 0 ] = AST__BAD; + new->lbnd[ 1 ] = AST__BAD; + new->ubnd[ 1 ] = AST__BAD; + new->simp_vertices = -INT_MAX; + new->edges = NULL; + new->startsat = NULL; + new->totlen = 0.0; + new->acw = 1; + new->stale = 1; + +/* Ensure the vertices are stored such that the unnegated Polygon + represents the inside of the polygon. */ + EnsureInside( new, status ); + +/* If an error occurred, clean up by deleting the new Polygon. */ + if ( !astOK ) new = astDelete( new ); + } + +/* Free resources. */ + pset = astAnnul( pset ); + + } + +/* Return a pointer to the new Polygon. */ + return new; +} + +AstPolygon *astLoadPolygon_( void *mem, size_t size, AstPolygonVtab *vtab, + const char *name, AstChannel *channel, int *status ) { +/* +*+ +* Name: +* astLoadPolygon + +* Purpose: +* Load a Polygon. + +* Type: +* Protected function. + +* Synopsis: +* #include "polygon.h" +* AstPolygon *astLoadPolygon( void *mem, size_t size, AstPolygonVtab *vtab, +* const char *name, AstChannel *channel ) + +* Class Membership: +* Polygon loader. + +* Description: +* This function is provided to load a new Polygon using data read +* from a Channel. It first loads the data used by the parent class +* (which allocates memory if necessary) and then initialises a +* Polygon structure in this memory, using data read from the input +* Channel. +* +* If the "init" flag is set, it also initialises the contents of a +* virtual function table for a Polygon at the start of the memory +* passed via the "vtab" parameter. + +* Parameters: +* mem +* A pointer to the memory into which the Polygon is to be +* loaded. This must be of sufficient size to accommodate the +* Polygon data (sizeof(Polygon)) plus any data used by derived +* classes. If a value of NULL is given, this function will +* allocate the memory itself using the "size" parameter to +* determine its size. +* size +* The amount of memory used by the Polygon (plus derived class +* data). This will be used to allocate memory if a value of +* NULL is given for the "mem" parameter. This value is also +* stored in the Polygon structure, so a valid value must be +* supplied even if not required for allocating memory. +* +* If the "vtab" parameter is NULL, the "size" value is ignored +* and sizeof(AstPolygon) is used instead. +* vtab +* Pointer to the start of the virtual function table to be +* associated with the new Polygon. If this is NULL, a pointer +* to the (static) virtual function table for the Polygon class +* is used instead. +* name +* Pointer to a constant null-terminated character string which +* contains the name of the class to which the new object +* belongs (it is this pointer value that will subsequently be +* returned by the astGetClass method). +* +* If the "vtab" parameter is NULL, the "name" value is ignored +* and a pointer to the string "Polygon" is used instead. + +* Returned Value: +* A pointer to the new Polygon. + +* Notes: +* - A null pointer will be returned if this function is invoked +* with the global error status set, or if it should fail for any +* reason. +*- +*/ + +/* Local Variables: */ + astDECLARE_GLOBALS /* Pointer to thread-specific global data */ + AstPolygon *new; /* Pointer to the new Polygon */ + int order; /* Is the new (STC) order convention used? */ + +/* Initialise. */ + new = NULL; + +/* Check the global error status. */ + if ( !astOK ) return new; + +/* Get a pointer to the thread specific global data structure. */ + astGET_GLOBALS(channel); + +/* If a NULL virtual function table has been supplied, then this is + the first loader to be invoked for this Polygon. In this case the + Polygon belongs to this class, so supply appropriate values to be + passed to the parent class loader (and its parent, etc.). */ + if ( !vtab ) { + size = sizeof( AstPolygon ); + vtab = &class_vtab; + name = "Polygon"; + +/* If required, initialise the virtual function table for this class. */ + if ( !class_init ) { + astInitPolygonVtab( vtab, name ); + class_init = 1; + } + } + +/* Invoke the parent class loader to load data for all the ancestral + classes of the current one, returning a pointer to the resulting + partly-built Polygon. */ + new = astLoadRegion( mem, size, (AstRegionVtab *) vtab, name, + channel ); + + if ( astOK ) { + +/* Read input data. */ +/* ================ */ +/* Request the input Channel to read all the input data appropriate to + this class into the internal "values list". */ + astReadClassData( channel, "Polygon" ); + +/* Now read each individual data item from this list and use it to + initialise the appropriate instance variable(s) for this class. */ + +/* In the case of attributes, we first read the "raw" input value, + supplying the "unset" value as the default. If a "set" value is + obtained, we then use the appropriate (private) Set... member + function to validate and set the value properly. */ + + new->simp_vertices = astReadInt( channel, "simpvt", -INT_MAX ); + if ( TestSimpVertices( new, status ) ) SetSimpVertices( new, new->simp_vertices, status ); + +/* A flag indicating what order the vertices are stored in. See the Dump + function. */ + order = astReadInt( channel, "order", 0 ); + +/* Initialise other class properties. */ + new->lbnd[ 0 ] = AST__BAD; + new->ubnd[ 0 ] = AST__BAD; + new->lbnd[ 1 ] = AST__BAD; + new->ubnd[ 1 ] = AST__BAD; + new->edges = NULL; + new->startsat = NULL; + new->totlen = 0.0; + new->acw = 1; + new->stale = 1; + +/* If the order in which the vertices were written used the old AST + convention, negate the Polygon so that it is consistent with the + current conevtion (based on STC). */ + if( ! order ) astNegate( new ); + +/* Ensure the vertices are stored such that the unnegated Polygon + represents the inside of the polygon. */ + EnsureInside( new, status ); + +/* If an error occurred, clean up by deleting the new Polygon. */ + if ( !astOK ) new = astDelete( new ); + } + +/* Return the new Polygon pointer. */ + return new; +} + +/* Virtual function interfaces. */ +/* ============================ */ +/* These provide the external interface to the virtual functions defined by + this class. Each simply checks the global error status and then locates and + executes the appropriate member function, using the function pointer stored + in the object's virtual function table (this pointer is located using the + astMEMBER macro defined in "object.h"). + + Note that the member function may not be the one defined here, as it may + have been over-ridden by a derived class. However, it should still have the + same interface. */ + + +AstPolygon *astDownsize_( AstPolygon *this, double maxerr, int maxvert, + int *status ) { + if ( !astOK ) return NULL; + return (**astMEMBER(this,Polygon,Downsize))( this, maxerr, maxvert, status ); +} + + |