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/*
* Smithsonian Astrophysical Observatory, Cambridge, MA, USA
* This code has been modified under the terms listed below and is made
* available under the same terms.
*/
/*
* bltGrMisc.c --
*
* This module implements miscellaneous routines for the BLT graph widget.
*
* Copyright 1993-2004 George A Howlett.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <assert.h>
#include <stdarg.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include "bltInt.h"
#include "bltGraph.h"
// Converts a string in the form "@x,y" into an XPoint structure of the x
// and y coordinates.
int Blt_GetXY(Tcl_Interp* interp, Tk_Window tkwin, const char* string,
int* xPtr, int* yPtr)
{
char *comma;
int result;
int x, y;
if ((string == NULL) || (*string == '\0')) {
*xPtr = *yPtr = -SHRT_MAX;
return TCL_OK;
}
if (*string != '@') {
goto badFormat;
}
comma = strchr(string + 1, ',');
if (comma == NULL) {
goto badFormat;
}
*comma = '\0';
result = ((Tk_GetPixels(interp, tkwin, string + 1, &x) == TCL_OK) &&
(Tk_GetPixels(interp, tkwin, comma + 1, &y) == TCL_OK));
*comma = ',';
if (!result) {
Tcl_AppendResult(interp, ": can't parse position \"", string, "\"",
(char *)NULL);
return TCL_ERROR;
}
*xPtr = x, *yPtr = y;
return TCL_OK;
badFormat:
Tcl_AppendResult(interp, "bad position \"", string,
"\": should be \"@x,y\"", (char *)NULL);
return TCL_ERROR;
}
int Blt_PointInSegments(Point2d* samplePtr, Segment2d* segments,
int nSegments, double halo)
{
Segment2d *sp, *send;
double minDist;
minDist = DBL_MAX;
for (sp = segments, send = sp + nSegments; sp < send; sp++) {
double dist;
double left, right, top, bottom;
Point2d p, t;
t = Blt_GetProjection((int)samplePtr->x, (int)samplePtr->y,
&sp->p, &sp->q);
if (sp->p.x > sp->q.x) {
right = sp->p.x, left = sp->q.x;
} else {
right = sp->q.x, left = sp->p.x;
}
if (sp->p.y > sp->q.y) {
bottom = sp->p.y, top = sp->q.y;
} else {
bottom = sp->q.y, top = sp->p.y;
}
p.x = BOUND(t.x, left, right);
p.y = BOUND(t.y, top, bottom);
dist = hypot(p.x - samplePtr->x, p.y - samplePtr->y);
if (dist < minDist) {
minDist = dist;
}
}
return (minDist < halo);
}
int Blt_PointInPolygon(Point2d *s, Point2d *points, int nPoints)
{
Point2d *p, *q, *qend;
int count;
count = 0;
for (p = points, q = p + 1, qend = p + nPoints; q < qend; p++, q++) {
if (((p->y <= s->y) && (s->y < q->y)) ||
((q->y <= s->y) && (s->y < p->y))) {
double b;
b = (q->x - p->x) * (s->y - p->y) / (q->y - p->y) + p->x;
if (s->x < b) {
count++; /* Count the number of intersections. */
}
}
}
return (count & 0x01);
}
int Blt_RegionInPolygon(Region2d *regionPtr, Point2d *points, int nPoints,
int enclosed)
{
Point2d *pp, *pend;
if (enclosed) {
/*
* All points of the polygon must be inside the rectangle.
*/
for (pp = points, pend = pp + nPoints; pp < pend; pp++) {
if ((pp->x < regionPtr->left) || (pp->x > regionPtr->right) ||
(pp->y < regionPtr->top) || (pp->y > regionPtr->bottom)) {
return FALSE; /* One point is exterior. */
}
}
return TRUE;
} else {
Point2d r;
/*
* If any segment of the polygon clips the bounding region, the
* polygon overlaps the rectangle.
*/
points[nPoints] = points[0];
for (pp = points, pend = pp + nPoints; pp < pend; pp++) {
Point2d p, q;
p = *pp;
q = *(pp + 1);
if (Blt_LineRectClip(regionPtr, &p, &q)) {
return TRUE;
}
}
/*
* Otherwise the polygon and rectangle are either disjoint or
* enclosed. Check if one corner of the rectangle is inside the
* polygon.
*/
r.x = regionPtr->left;
r.y = regionPtr->top;
return Blt_PointInPolygon(&r, points, nPoints);
}
}
/*
*---------------------------------------------------------------------------
* Generates a bounding box representing the plotting area of the
* graph. This data structure is used to clip the points and line
* segments of the line element.
* The clip region is the plotting area plus such arbitrary extra space.
* The reason we clip with a bounding box larger than the plot area is so
* that symbols will be drawn even if their center point isn't in the
* plotting area.
*---------------------------------------------------------------------------
*/
void Blt_GraphExtents(Graph* graphPtr, Region2d *regionPtr)
{
regionPtr->left = (double)(graphPtr->hOffset - graphPtr->xPad);
regionPtr->top = (double)(graphPtr->vOffset - graphPtr->yPad);
regionPtr->right = (double)(graphPtr->hOffset + graphPtr->hRange +
graphPtr->xPad);
regionPtr->bottom = (double)(graphPtr->vOffset + graphPtr->vRange +
graphPtr->yPad);
}
static int ClipTest (double ds, double dr, double *t1, double *t2)
{
double t;
if (ds < 0.0) {
t = dr / ds;
if (t > *t2) {
return FALSE;
}
if (t > *t1) {
*t1 = t;
}
} else if (ds > 0.0) {
t = dr / ds;
if (t < *t1) {
return FALSE;
}
if (t < *t2) {
*t2 = t;
}
} else {
/* d = 0, so line is parallel to this clipping edge */
if (dr < 0.0) { /* Line is outside clipping edge */
return FALSE;
}
}
return TRUE;
}
/*
*---------------------------------------------------------------------------
* Clips the given line segment to a rectangular region. The coordinates
* of the clipped line segment are returned. The original coordinates
* are overwritten.
*
* Reference:
* Liang, Y-D., and B. Barsky, A new concept and method for
* Line Clipping, ACM, TOG,3(1), 1984, pp.1-22.
*---------------------------------------------------------------------------
*/
int Blt_LineRectClip(Region2d* regionPtr, Point2d *p, Point2d *q)
{
double t1, t2;
double dx, dy;
t1 = 0.0, t2 = 1.0;
dx = q->x - p->x;
if ((ClipTest (-dx, p->x - regionPtr->left, &t1, &t2)) &&
(ClipTest (dx, regionPtr->right - p->x, &t1, &t2))) {
dy = q->y - p->y;
if ((ClipTest (-dy, p->y - regionPtr->top, &t1, &t2)) &&
(ClipTest (dy, regionPtr->bottom - p->y, &t1, &t2))) {
if (t2 < 1.0) {
q->x = p->x + t2 * dx;
q->y = p->y + t2 * dy;
}
if (t1 > 0.0) {
p->x += t1 * dx;
p->y += t1 * dy;
}
return TRUE;
}
}
return FALSE;
}
/*
*---------------------------------------------------------------------------
* Clips the given polygon to a rectangular region. The resulting
* polygon is returned. Note that the resulting polyon may be complex,
* connected by zero width/height segments. The drawing routine (such as
* XFillPolygon) will not draw a connecting segment.
*
* Reference:
* Liang Y. D. and Brian A. Barsky, "Analysis and Algorithm for
* Polygon Clipping", Communications of ACM, Vol. 26,
* p.868-877, 1983
*---------------------------------------------------------------------------
*/
#define EPSILON FLT_EPSILON
#define AddVertex(vx, vy) r->x=(vx), r->y=(vy), r++, count++
#define LastVertex(vx, vy) r->x=(vx), r->y=(vy), count++
int Blt_PolyRectClip(Region2d *regionPtr, Point2d *points, int nPoints,
Point2d *clipPts)
{
Point2d *p; /* First vertex of input polygon edge. */
Point2d *pend;
Point2d *q; /* Last vertex of input polygon edge. */
Point2d *r;
int count;
r = clipPts;
count = 0; /* Counts # of vertices in output polygon. */
points[nPoints] = points[0];
for (p = points, q = p + 1, pend = p + nPoints; p < pend; p++, q++) {
double dx, dy;
double tin1, tin2, tinx, tiny;
double xin, yin, xout, yout;
dx = q->x - p->x; /* X-direction */
dy = q->y - p->y; /* Y-direction */
if (fabs(dx) < EPSILON) {
dx = (p->x > regionPtr->left) ? -EPSILON : EPSILON ;
}
if (fabs(dy) < EPSILON) {
dy = (p->y > regionPtr->top) ? -EPSILON : EPSILON ;
}
if (dx > 0.0) { /* Left */
xin = regionPtr->left;
xout = regionPtr->right + 1.0;
} else { /* Right */
xin = regionPtr->right + 1.0;
xout = regionPtr->left;
}
if (dy > 0.0) { /* Top */
yin = regionPtr->top;
yout = regionPtr->bottom + 1.0;
} else { /* Bottom */
yin = regionPtr->bottom + 1.0;
yout = regionPtr->top;
}
tinx = (xin - p->x) / dx;
tiny = (yin - p->y) / dy;
if (tinx < tiny) { /* Hits x first */
tin1 = tinx;
tin2 = tiny;
} else { /* Hits y first */
tin1 = tiny;
tin2 = tinx;
}
if (tin1 <= 1.0) {
if (tin1 > 0.0) {
AddVertex(xin, yin);
}
if (tin2 <= 1.0) {
double toutx, touty, tout1;
toutx = (xout - p->x) / dx;
touty = (yout - p->y) / dy;
tout1 = MIN(toutx, touty);
if ((tin2 > 0.0) || (tout1 > 0.0)) {
if (tin2 <= tout1) {
if (tin2 > 0.0) {
if (tinx > tiny) {
AddVertex(xin, p->y + tinx * dy);
} else {
AddVertex(p->x + tiny * dx, yin);
}
}
if (tout1 < 1.0) {
if (toutx < touty) {
AddVertex(xout, p->y + toutx * dy);
} else {
AddVertex(p->x + touty * dx, yout);
}
} else {
AddVertex(q->x, q->y);
}
} else {
if (tinx > tiny) {
AddVertex(xin, yout);
} else {
AddVertex(xout, yin);
}
}
}
}
}
}
if (count > 0) {
LastVertex(clipPts[0].x, clipPts[0].y);
}
return count;
}
/*
*---------------------------------------------------------------------------
* Computes the projection of a point on a line. The line (given by two
* points), is assumed the be infinite.
*
* Compute the slope (angle) of the line and rotate it 90 degrees. Using
* the slope-intercept method (we know the second line from the sample
* test point and the computed slope), then find the intersection of both
* lines. This will be the projection of the sample point on the first
* line.
*---------------------------------------------------------------------------
*/
Point2d Blt_GetProjection(int x, int y, Point2d *p, Point2d *q)
{
double dx, dy;
Point2d t;
dx = p->x - q->x;
dy = p->y - q->y;
/* Test for horizontal and vertical lines */
if (fabs(dx) < DBL_EPSILON) {
t.x = p->x, t.y = (double)y;
} else if (fabs(dy) < DBL_EPSILON) {
t.x = (double)x, t.y = p->y;
} else {
double m1, m2; /* Slope of both lines */
double b1, b2; /* y-intercepts */
double midX, midY; /* Midpoint of line segment. */
double ax, ay, bx, by;
/* Compute the slope and intercept of PQ. */
m1 = (dy / dx);
b1 = p->y - (p->x * m1);
/*
* Compute the slope and intercept of a second line segment: one that
* intersects through sample X-Y coordinate with a slope perpendicular
* to original line.
*/
/* Find midpoint of PQ. */
midX = (p->x + q->x) * 0.5;
midY = (p->y + q->y) * 0.5;
/* Rotate the line 90 degrees */
ax = midX - (0.5 * dy);
ay = midY - (0.5 * -dx);
bx = midX + (0.5 * dy);
by = midY + (0.5 * -dx);
m2 = (ay - by) / (ax - bx);
b2 = y - (x * m2);
/*
* Given the equations of two lines which contain the same point,
*
* y = m1 * x + b1
* y = m2 * x + b2
*
* solve for the intersection.
*
* x = (b2 - b1) / (m1 - m2)
* y = m1 * x + b1
*
*/
t.x = (b2 - b1) / (m1 - m2);
t.y = m1 * t.x + b1;
}
return t;
}
/*
*---------------------------------------------------------------------------
* Invoke a TCL command to the scrollbar, defining the new position and
* length of the scroll. See the Tk documentation for further information
* on the scrollbar. It is assumed the scrollbar command prefix is
* valid.
*---------------------------------------------------------------------------
*/
void Blt_UpdateScrollbar(Tcl_Interp* interp, Tcl_Obj *scrollCmdObjPtr,
int first, int last, int width)
{
Tcl_Obj *cmdObjPtr;
double firstFract, lastFract;
firstFract = 0.0, lastFract = 1.0;
if (width > 0) {
firstFract = (double)first / (double)width;
lastFract = (double)last / (double)width;
}
cmdObjPtr = Tcl_DuplicateObj(scrollCmdObjPtr);
Tcl_ListObjAppendElement(interp, cmdObjPtr, Tcl_NewDoubleObj(firstFract));
Tcl_ListObjAppendElement(interp, cmdObjPtr, Tcl_NewDoubleObj(lastFract));
Tcl_IncrRefCount(cmdObjPtr);
if (Tcl_EvalObjEx(interp, cmdObjPtr, TCL_EVAL_GLOBAL) != TCL_OK) {
Tcl_BackgroundError(interp);
}
Tcl_DecrRefCount(cmdObjPtr);
}
/*
*---------------------------------------------------------------------------
* Like Tk_GetGC, but doesn't share the GC with any other widget. This
* is needed because the certain GC parameters (like dashes) can not be
* set via XCreateGC, therefore there is no way for Tk's hashing
* mechanism to recognize that two such GCs differ.
*---------------------------------------------------------------------------
*/
GC Blt_GetPrivateGC(Tk_Window tkwin, unsigned long gcMask, XGCValues *valuePtr)
{
GC gc;
Pixmap pixmap;
Drawable drawable;
Display *display;
pixmap = None;
drawable = Tk_WindowId(tkwin);
display = Tk_Display(tkwin);
if (drawable == None)
drawable = Tk_RootWindow(tkwin);
gc = XCreateGC(display, drawable, gcMask, valuePtr);
if (pixmap != None) {
Tk_FreePixmap(display, pixmap);
}
return gc;
}
void Blt_FreePrivateGC(Display *display, GC gc)
{
Tk_FreeXId(display, (XID) XGContextFromGC(gc));
XFreeGC(display, gc);
}
void Blt_SetDashes(Display *display, GC gc, Blt_Dashes *dashesPtr)
{
XSetDashes(display, gc, dashesPtr->offset, (const char *)dashesPtr->values,
(int)strlen((char *)dashesPtr->values));
}
void Blt_Draw2DSegments(Display *display, Drawable drawable, GC gc,
Segment2d *segments, int nSegments)
{
XSegment *dp, *xsegments;
Segment2d *sp, *send;
xsegments = malloc(nSegments * sizeof(XSegment));
if (xsegments == NULL) {
return;
}
dp = xsegments;
for (sp = segments, send = sp + nSegments; sp < send; sp++) {
dp->x1 = (short int)sp->p.x;
dp->y1 = (short int)sp->p.y;
dp->x2 = (short int)sp->q.x;
dp->y2 = (short int)sp->q.y;
dp++;
}
XDrawSegments(display, drawable, gc, xsegments, nSegments);
free(xsegments);
}
long Blt_MaxRequestSize(Display *display, size_t elemSize)
{
static long maxSizeBytes = 0L;
if (maxSizeBytes == 0L) {
long size;
size = XExtendedMaxRequestSize(display);
if (size == 0) {
size = XMaxRequestSize(display);
}
size -= (4 * elemSize);
/* maxSizeBytes = (size * 4); */
maxSizeBytes = size;
}
return (maxSizeBytes / elemSize);
}
|