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diff --git a/generic/tkCanvArc.c b/generic/tkCanvArc.c
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+/*
+ * tkCanvArc.c --
+ *
+ * This file implements arc items for canvas widgets.
+ *
+ * Copyright (c) 1992-1994 The Regents of the University of California.
+ * Copyright (c) 1994-1995 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tkCanvArc.c 1.34 97/04/25 16:50:56
+ */
+
+#include <stdio.h>
+#include "tkPort.h"
+#include "tkInt.h"
+
+/*
+ * The structure below defines the record for each arc item.
+ */
+
+typedef struct ArcItem {
+ Tk_Item header; /* Generic stuff that's the same for all
+ * types. MUST BE FIRST IN STRUCTURE. */
+ double bbox[4]; /* Coordinates (x1, y1, x2, y2) of bounding
+ * box for oval of which arc is a piece. */
+ double start; /* Angle at which arc begins, in degrees
+ * between 0 and 360. */
+ double extent; /* Extent of arc (angular distance from
+ * start to end of arc) in degrees between
+ * -360 and 360. */
+ double *outlinePtr; /* Points to (x,y) coordinates for points
+ * that define one or two closed polygons
+ * representing the portion of the outline
+ * that isn't part of the arc (the V-shape
+ * for a pie slice or a line-like segment
+ * for a chord). Malloc'ed. */
+ int numOutlinePoints; /* Number of points at outlinePtr. Zero
+ * means no space allocated. */
+ int width; /* Width of outline (in pixels). */
+ XColor *outlineColor; /* Color for outline. NULL means don't
+ * draw outline. */
+ XColor *fillColor; /* Color for filling arc (used for drawing
+ * outline too when style is "arc"). NULL
+ * means don't fill arc. */
+ Pixmap fillStipple; /* Stipple bitmap for filling item. */
+ Pixmap outlineStipple; /* Stipple bitmap for outline. */
+ Tk_Uid style; /* How to draw arc: arc, chord, or pieslice. */
+ GC outlineGC; /* Graphics context for outline. */
+ GC fillGC; /* Graphics context for filling item. */
+ double center1[2]; /* Coordinates of center of arc outline at
+ * start (see ComputeArcOutline). */
+ double center2[2]; /* Coordinates of center of arc outline at
+ * start+extent (see ComputeArcOutline). */
+} ArcItem;
+
+/*
+ * The definitions below define the sizes of the polygons used to
+ * display outline information for various styles of arcs:
+ */
+
+#define CHORD_OUTLINE_PTS 7
+#define PIE_OUTLINE1_PTS 6
+#define PIE_OUTLINE2_PTS 7
+
+/*
+ * Information used for parsing configuration specs:
+ */
+
+static Tk_CustomOption tagsOption = {Tk_CanvasTagsParseProc,
+ Tk_CanvasTagsPrintProc, (ClientData) NULL
+};
+
+static Tk_ConfigSpec configSpecs[] = {
+ {TK_CONFIG_DOUBLE, "-extent", (char *) NULL, (char *) NULL,
+ "90", Tk_Offset(ArcItem, extent), TK_CONFIG_DONT_SET_DEFAULT},
+ {TK_CONFIG_COLOR, "-fill", (char *) NULL, (char *) NULL,
+ (char *) NULL, Tk_Offset(ArcItem, fillColor), TK_CONFIG_NULL_OK},
+ {TK_CONFIG_COLOR, "-outline", (char *) NULL, (char *) NULL,
+ "black", Tk_Offset(ArcItem, outlineColor), TK_CONFIG_NULL_OK},
+ {TK_CONFIG_BITMAP, "-outlinestipple", (char *) NULL, (char *) NULL,
+ (char *) NULL, Tk_Offset(ArcItem, outlineStipple), TK_CONFIG_NULL_OK},
+ {TK_CONFIG_DOUBLE, "-start", (char *) NULL, (char *) NULL,
+ "0", Tk_Offset(ArcItem, start), TK_CONFIG_DONT_SET_DEFAULT},
+ {TK_CONFIG_BITMAP, "-stipple", (char *) NULL, (char *) NULL,
+ (char *) NULL, Tk_Offset(ArcItem, fillStipple), TK_CONFIG_NULL_OK},
+ {TK_CONFIG_UID, "-style", (char *) NULL, (char *) NULL,
+ "pieslice", Tk_Offset(ArcItem, style), TK_CONFIG_DONT_SET_DEFAULT},
+ {TK_CONFIG_CUSTOM, "-tags", (char *) NULL, (char *) NULL,
+ (char *) NULL, 0, TK_CONFIG_NULL_OK, &tagsOption},
+ {TK_CONFIG_PIXELS, "-width", (char *) NULL, (char *) NULL,
+ "1", Tk_Offset(ArcItem, width), TK_CONFIG_DONT_SET_DEFAULT},
+ {TK_CONFIG_END, (char *) NULL, (char *) NULL, (char *) NULL,
+ (char *) NULL, 0, 0}
+};
+
+/*
+ * Prototypes for procedures defined in this file:
+ */
+
+static void ComputeArcBbox _ANSI_ARGS_((Tk_Canvas canvas,
+ ArcItem *arcPtr));
+static int ConfigureArc _ANSI_ARGS_((Tcl_Interp *interp,
+ Tk_Canvas canvas, Tk_Item *itemPtr, int argc,
+ char **argv, int flags));
+static int CreateArc _ANSI_ARGS_((Tcl_Interp *interp,
+ Tk_Canvas canvas, struct Tk_Item *itemPtr,
+ int argc, char **argv));
+static void DeleteArc _ANSI_ARGS_((Tk_Canvas canvas,
+ Tk_Item *itemPtr, Display *display));
+static void DisplayArc _ANSI_ARGS_((Tk_Canvas canvas,
+ Tk_Item *itemPtr, Display *display, Drawable dst,
+ int x, int y, int width, int height));
+static int ArcCoords _ANSI_ARGS_((Tcl_Interp *interp,
+ Tk_Canvas canvas, Tk_Item *itemPtr, int argc,
+ char **argv));
+static int ArcToArea _ANSI_ARGS_((Tk_Canvas canvas,
+ Tk_Item *itemPtr, double *rectPtr));
+static double ArcToPoint _ANSI_ARGS_((Tk_Canvas canvas,
+ Tk_Item *itemPtr, double *coordPtr));
+static int ArcToPostscript _ANSI_ARGS_((Tcl_Interp *interp,
+ Tk_Canvas canvas, Tk_Item *itemPtr, int prepass));
+static void ScaleArc _ANSI_ARGS_((Tk_Canvas canvas,
+ Tk_Item *itemPtr, double originX, double originY,
+ double scaleX, double scaleY));
+static void TranslateArc _ANSI_ARGS_((Tk_Canvas canvas,
+ Tk_Item *itemPtr, double deltaX, double deltaY));
+static int AngleInRange _ANSI_ARGS_((double x, double y,
+ double start, double extent));
+static void ComputeArcOutline _ANSI_ARGS_((ArcItem *arcPtr));
+static int HorizLineToArc _ANSI_ARGS_((double x1, double x2,
+ double y, double rx, double ry,
+ double start, double extent));
+static int VertLineToArc _ANSI_ARGS_((double x, double y1,
+ double y2, double rx, double ry,
+ double start, double extent));
+
+/*
+ * The structures below defines the arc item types by means of procedures
+ * that can be invoked by generic item code.
+ */
+
+Tk_ItemType tkArcType = {
+ "arc", /* name */
+ sizeof(ArcItem), /* itemSize */
+ CreateArc, /* createProc */
+ configSpecs, /* configSpecs */
+ ConfigureArc, /* configureProc */
+ ArcCoords, /* coordProc */
+ DeleteArc, /* deleteProc */
+ DisplayArc, /* displayProc */
+ 0, /* alwaysRedraw */
+ ArcToPoint, /* pointProc */
+ ArcToArea, /* areaProc */
+ ArcToPostscript, /* postscriptProc */
+ ScaleArc, /* scaleProc */
+ TranslateArc, /* translateProc */
+ (Tk_ItemIndexProc *) NULL, /* indexProc */
+ (Tk_ItemCursorProc *) NULL, /* icursorProc */
+ (Tk_ItemSelectionProc *) NULL, /* selectionProc */
+ (Tk_ItemInsertProc *) NULL, /* insertProc */
+ (Tk_ItemDCharsProc *) NULL, /* dTextProc */
+ (Tk_ItemType *) NULL /* nextPtr */
+};
+
+#ifndef PI
+# define PI 3.14159265358979323846
+#endif
+
+/*
+ * The uid's below comprise the legal values for the "-style"
+ * option for arcs.
+ */
+
+static Tk_Uid arcUid = NULL;
+static Tk_Uid chordUid = NULL;
+static Tk_Uid pieSliceUid = NULL;
+
+/*
+ *--------------------------------------------------------------
+ *
+ * CreateArc --
+ *
+ * This procedure is invoked to create a new arc item in
+ * a canvas.
+ *
+ * Results:
+ * A standard Tcl return value. If an error occurred in
+ * creating the item, then an error message is left in
+ * interp->result; in this case itemPtr is
+ * left uninitialized, so it can be safely freed by the
+ * caller.
+ *
+ * Side effects:
+ * A new arc item is created.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+CreateArc(interp, canvas, itemPtr, argc, argv)
+ Tcl_Interp *interp; /* Interpreter for error reporting. */
+ Tk_Canvas canvas; /* Canvas to hold new item. */
+ Tk_Item *itemPtr; /* Record to hold new item; header
+ * has been initialized by caller. */
+ int argc; /* Number of arguments in argv. */
+ char **argv; /* Arguments describing arc. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+
+ if (argc < 4) {
+ Tcl_AppendResult(interp, "wrong # args: should be \"",
+ Tk_PathName(Tk_CanvasTkwin(canvas)), " create ",
+ itemPtr->typePtr->name, " x1 y1 x2 y2 ?options?\"",
+ (char *) NULL);
+ return TCL_ERROR;
+ }
+
+ /*
+ * Carry out once-only initialization.
+ */
+
+ if (arcUid == NULL) {
+ arcUid = Tk_GetUid("arc");
+ chordUid = Tk_GetUid("chord");
+ pieSliceUid = Tk_GetUid("pieslice");
+ }
+
+ /*
+ * Carry out initialization that is needed in order to clean
+ * up after errors during the the remainder of this procedure.
+ */
+
+ arcPtr->start = 0;
+ arcPtr->extent = 90;
+ arcPtr->outlinePtr = NULL;
+ arcPtr->numOutlinePoints = 0;
+ arcPtr->width = 1;
+ arcPtr->outlineColor = NULL;
+ arcPtr->fillColor = NULL;
+ arcPtr->fillStipple = None;
+ arcPtr->outlineStipple = None;
+ arcPtr->style = pieSliceUid;
+ arcPtr->outlineGC = None;
+ arcPtr->fillGC = None;
+
+ /*
+ * Process the arguments to fill in the item record.
+ */
+
+ if ((Tk_CanvasGetCoord(interp, canvas, argv[0], &arcPtr->bbox[0]) != TCL_OK)
+ || (Tk_CanvasGetCoord(interp, canvas, argv[1],
+ &arcPtr->bbox[1]) != TCL_OK)
+ || (Tk_CanvasGetCoord(interp, canvas, argv[2],
+ &arcPtr->bbox[2]) != TCL_OK)
+ || (Tk_CanvasGetCoord(interp, canvas, argv[3],
+ &arcPtr->bbox[3]) != TCL_OK)) {
+ return TCL_ERROR;
+ }
+
+ if (ConfigureArc(interp, canvas, itemPtr, argc-4, argv+4, 0) != TCL_OK) {
+ DeleteArc(canvas, itemPtr, Tk_Display(Tk_CanvasTkwin(canvas)));
+ return TCL_ERROR;
+ }
+ return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ArcCoords --
+ *
+ * This procedure is invoked to process the "coords" widget
+ * command on arcs. See the user documentation for details
+ * on what it does.
+ *
+ * Results:
+ * Returns TCL_OK or TCL_ERROR, and sets interp->result.
+ *
+ * Side effects:
+ * The coordinates for the given item may be changed.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+ArcCoords(interp, canvas, itemPtr, argc, argv)
+ Tcl_Interp *interp; /* Used for error reporting. */
+ Tk_Canvas canvas; /* Canvas containing item. */
+ Tk_Item *itemPtr; /* Item whose coordinates are to be
+ * read or modified. */
+ int argc; /* Number of coordinates supplied in
+ * argv. */
+ char **argv; /* Array of coordinates: x1, y1,
+ * x2, y2, ... */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+ char c0[TCL_DOUBLE_SPACE], c1[TCL_DOUBLE_SPACE];
+ char c2[TCL_DOUBLE_SPACE], c3[TCL_DOUBLE_SPACE];
+
+ if (argc == 0) {
+ Tcl_PrintDouble(interp, arcPtr->bbox[0], c0);
+ Tcl_PrintDouble(interp, arcPtr->bbox[1], c1);
+ Tcl_PrintDouble(interp, arcPtr->bbox[2], c2);
+ Tcl_PrintDouble(interp, arcPtr->bbox[3], c3);
+ Tcl_AppendResult(interp, c0, " ", c1, " ", c2, " ", c3,
+ (char *) NULL);
+ } else if (argc == 4) {
+ if ((Tk_CanvasGetCoord(interp, canvas, argv[0],
+ &arcPtr->bbox[0]) != TCL_OK)
+ || (Tk_CanvasGetCoord(interp, canvas, argv[1],
+ &arcPtr->bbox[1]) != TCL_OK)
+ || (Tk_CanvasGetCoord(interp, canvas, argv[2],
+ &arcPtr->bbox[2]) != TCL_OK)
+ || (Tk_CanvasGetCoord(interp, canvas, argv[3],
+ &arcPtr->bbox[3]) != TCL_OK)) {
+ return TCL_ERROR;
+ }
+ ComputeArcBbox(canvas, arcPtr);
+ } else {
+ sprintf(interp->result,
+ "wrong # coordinates: expected 0 or 4, got %d",
+ argc);
+ return TCL_ERROR;
+ }
+ return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ConfigureArc --
+ *
+ * This procedure is invoked to configure various aspects
+ * of a arc item, such as its outline and fill colors.
+ *
+ * Results:
+ * A standard Tcl result code. If an error occurs, then
+ * an error message is left in interp->result.
+ *
+ * Side effects:
+ * Configuration information, such as colors and stipple
+ * patterns, may be set for itemPtr.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+ConfigureArc(interp, canvas, itemPtr, argc, argv, flags)
+ Tcl_Interp *interp; /* Used for error reporting. */
+ Tk_Canvas canvas; /* Canvas containing itemPtr. */
+ Tk_Item *itemPtr; /* Arc item to reconfigure. */
+ int argc; /* Number of elements in argv. */
+ char **argv; /* Arguments describing things to configure. */
+ int flags; /* Flags to pass to Tk_ConfigureWidget. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+ XGCValues gcValues;
+ GC newGC;
+ unsigned long mask;
+ int i;
+ Tk_Window tkwin;
+
+ tkwin = Tk_CanvasTkwin(canvas);
+ if (Tk_ConfigureWidget(interp, tkwin, configSpecs, argc, argv,
+ (char *) arcPtr, flags) != TCL_OK) {
+ return TCL_ERROR;
+ }
+
+ /*
+ * A few of the options require additional processing, such as
+ * style and graphics contexts.
+ */
+
+ i = (int) (arcPtr->start/360.0);
+ arcPtr->start -= i*360.0;
+ if (arcPtr->start < 0) {
+ arcPtr->start += 360.0;
+ }
+ i = (int) (arcPtr->extent/360.0);
+ arcPtr->extent -= i*360.0;
+
+ if ((arcPtr->style != arcUid) && (arcPtr->style != chordUid)
+ && (arcPtr->style != pieSliceUid)) {
+ Tcl_AppendResult(interp, "bad -style option \"",
+ arcPtr->style, "\": must be arc, chord, or pieslice",
+ (char *) NULL);
+ arcPtr->style = pieSliceUid;
+ return TCL_ERROR;
+ }
+
+ if (arcPtr->width < 0) {
+ arcPtr->width = 1;
+ }
+ if (arcPtr->outlineColor == NULL) {
+ newGC = None;
+ } else {
+ gcValues.foreground = arcPtr->outlineColor->pixel;
+ gcValues.cap_style = CapButt;
+ gcValues.line_width = arcPtr->width;
+ mask = GCForeground|GCCapStyle|GCLineWidth;
+ if (arcPtr->outlineStipple != None) {
+ gcValues.stipple = arcPtr->outlineStipple;
+ gcValues.fill_style = FillStippled;
+ mask |= GCStipple|GCFillStyle;
+ }
+ newGC = Tk_GetGC(tkwin, mask, &gcValues);
+ }
+ if (arcPtr->outlineGC != None) {
+ Tk_FreeGC(Tk_Display(tkwin), arcPtr->outlineGC);
+ }
+ arcPtr->outlineGC = newGC;
+
+ if ((arcPtr->fillColor == NULL) || (arcPtr->style == arcUid)) {
+ newGC = None;
+ } else {
+ gcValues.foreground = arcPtr->fillColor->pixel;
+ if (arcPtr->style == chordUid) {
+ gcValues.arc_mode = ArcChord;
+ } else {
+ gcValues.arc_mode = ArcPieSlice;
+ }
+ mask = GCForeground|GCArcMode;
+ if (arcPtr->fillStipple != None) {
+ gcValues.stipple = arcPtr->fillStipple;
+ gcValues.fill_style = FillStippled;
+ mask |= GCStipple|GCFillStyle;
+ }
+ newGC = Tk_GetGC(tkwin, mask, &gcValues);
+ }
+ if (arcPtr->fillGC != None) {
+ Tk_FreeGC(Tk_Display(tkwin), arcPtr->fillGC);
+ }
+ arcPtr->fillGC = newGC;
+
+ ComputeArcBbox(canvas, arcPtr);
+ return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * DeleteArc --
+ *
+ * This procedure is called to clean up the data structure
+ * associated with a arc item.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Resources associated with itemPtr are released.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+DeleteArc(canvas, itemPtr, display)
+ Tk_Canvas canvas; /* Info about overall canvas. */
+ Tk_Item *itemPtr; /* Item that is being deleted. */
+ Display *display; /* Display containing window for
+ * canvas. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+
+ if (arcPtr->numOutlinePoints != 0) {
+ ckfree((char *) arcPtr->outlinePtr);
+ }
+ if (arcPtr->outlineColor != NULL) {
+ Tk_FreeColor(arcPtr->outlineColor);
+ }
+ if (arcPtr->fillColor != NULL) {
+ Tk_FreeColor(arcPtr->fillColor);
+ }
+ if (arcPtr->fillStipple != None) {
+ Tk_FreeBitmap(display, arcPtr->fillStipple);
+ }
+ if (arcPtr->outlineStipple != None) {
+ Tk_FreeBitmap(display, arcPtr->outlineStipple);
+ }
+ if (arcPtr->outlineGC != None) {
+ Tk_FreeGC(display, arcPtr->outlineGC);
+ }
+ if (arcPtr->fillGC != None) {
+ Tk_FreeGC(display, arcPtr->fillGC);
+ }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ComputeArcBbox --
+ *
+ * This procedure is invoked to compute the bounding box of
+ * all the pixels that may be drawn as part of an arc.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The fields x1, y1, x2, and y2 are updated in the header
+ * for itemPtr.
+ *
+ *--------------------------------------------------------------
+ */
+
+ /* ARGSUSED */
+static void
+ComputeArcBbox(canvas, arcPtr)
+ Tk_Canvas canvas; /* Canvas that contains item. */
+ ArcItem *arcPtr; /* Item whose bbox is to be
+ * recomputed. */
+{
+ double tmp, center[2], point[2];
+
+ /*
+ * Make sure that the first coordinates are the lowest ones.
+ */
+
+ if (arcPtr->bbox[1] > arcPtr->bbox[3]) {
+ double tmp;
+ tmp = arcPtr->bbox[3];
+ arcPtr->bbox[3] = arcPtr->bbox[1];
+ arcPtr->bbox[1] = tmp;
+ }
+ if (arcPtr->bbox[0] > arcPtr->bbox[2]) {
+ double tmp;
+ tmp = arcPtr->bbox[2];
+ arcPtr->bbox[2] = arcPtr->bbox[0];
+ arcPtr->bbox[0] = tmp;
+ }
+
+ ComputeArcOutline(arcPtr);
+
+ /*
+ * To compute the bounding box, start with the the bbox formed
+ * by the two endpoints of the arc. Then add in the center of
+ * the arc's oval (if relevant) and the 3-o'clock, 6-o'clock,
+ * 9-o'clock, and 12-o'clock positions, if they are relevant.
+ */
+
+ arcPtr->header.x1 = arcPtr->header.x2 = (int) arcPtr->center1[0];
+ arcPtr->header.y1 = arcPtr->header.y2 = (int) arcPtr->center1[1];
+ TkIncludePoint((Tk_Item *) arcPtr, arcPtr->center2);
+ center[0] = (arcPtr->bbox[0] + arcPtr->bbox[2])/2;
+ center[1] = (arcPtr->bbox[1] + arcPtr->bbox[3])/2;
+ if (arcPtr->style != arcUid) {
+ TkIncludePoint((Tk_Item *) arcPtr, center);
+ }
+
+ tmp = -arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ point[0] = arcPtr->bbox[2];
+ point[1] = center[1];
+ TkIncludePoint((Tk_Item *) arcPtr, point);
+ }
+ tmp = 90.0 - arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ point[0] = center[0];
+ point[1] = arcPtr->bbox[1];
+ TkIncludePoint((Tk_Item *) arcPtr, point);
+ }
+ tmp = 180.0 - arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ point[0] = arcPtr->bbox[0];
+ point[1] = center[1];
+ TkIncludePoint((Tk_Item *) arcPtr, point);
+ }
+ tmp = 270.0 - arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ point[0] = center[0];
+ point[1] = arcPtr->bbox[3];
+ TkIncludePoint((Tk_Item *) arcPtr, point);
+ }
+
+ /*
+ * Lastly, expand by the width of the arc (if the arc's outline is
+ * being drawn) and add one extra pixel just for safety.
+ */
+
+ if (arcPtr->outlineColor == NULL) {
+ tmp = 1;
+ } else {
+ tmp = (arcPtr->width + 1)/2 + 1;
+ }
+ arcPtr->header.x1 -= (int) tmp;
+ arcPtr->header.y1 -= (int) tmp;
+ arcPtr->header.x2 += (int) tmp;
+ arcPtr->header.y2 += (int) tmp;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * DisplayArc --
+ *
+ * This procedure is invoked to draw an arc item in a given
+ * drawable.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * ItemPtr is drawn in drawable using the transformation
+ * information in canvas.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+DisplayArc(canvas, itemPtr, display, drawable, x, y, width, height)
+ Tk_Canvas canvas; /* Canvas that contains item. */
+ Tk_Item *itemPtr; /* Item to be displayed. */
+ Display *display; /* Display on which to draw item. */
+ Drawable drawable; /* Pixmap or window in which to draw
+ * item. */
+ int x, y, width, height; /* Describes region of canvas that
+ * must be redisplayed (not used). */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+ short x1, y1, x2, y2;
+ int start, extent;
+
+ /*
+ * Compute the screen coordinates of the bounding box for the item,
+ * plus integer values for the angles.
+ */
+
+ Tk_CanvasDrawableCoords(canvas, arcPtr->bbox[0], arcPtr->bbox[1],
+ &x1, &y1);
+ Tk_CanvasDrawableCoords(canvas, arcPtr->bbox[2], arcPtr->bbox[3],
+ &x2, &y2);
+ if (x2 <= x1) {
+ x2 = x1+1;
+ }
+ if (y2 <= y1) {
+ y2 = y1+1;
+ }
+ start = (int) ((64*arcPtr->start) + 0.5);
+ extent = (int) ((64*arcPtr->extent) + 0.5);
+
+ /*
+ * Display filled arc first (if wanted), then outline. If the extent
+ * is zero then don't invoke XFillArc or XDrawArc, since this causes
+ * some window servers to crash and should be a no-op anyway.
+ */
+
+ if ((arcPtr->fillGC != None) && (extent != 0)) {
+ if (arcPtr->fillStipple != None) {
+ Tk_CanvasSetStippleOrigin(canvas, arcPtr->fillGC);
+ }
+ XFillArc(display, drawable, arcPtr->fillGC, x1, y1, (unsigned) (x2-x1),
+ (unsigned) (y2-y1), start, extent);
+ if (arcPtr->fillStipple != None) {
+ XSetTSOrigin(display, arcPtr->fillGC, 0, 0);
+ }
+ }
+ if (arcPtr->outlineGC != None) {
+ if (arcPtr->outlineStipple != None) {
+ Tk_CanvasSetStippleOrigin(canvas, arcPtr->outlineGC);
+ }
+ if (extent != 0) {
+ XDrawArc(display, drawable, arcPtr->outlineGC, x1, y1,
+ (unsigned) (x2-x1), (unsigned) (y2-y1), start, extent);
+ }
+
+ /*
+ * If the outline width is very thin, don't use polygons to draw
+ * the linear parts of the outline (this often results in nothing
+ * being displayed); just draw lines instead.
+ */
+
+ if (arcPtr->width <= 2) {
+ Tk_CanvasDrawableCoords(canvas, arcPtr->center1[0],
+ arcPtr->center1[1], &x1, &y1);
+ Tk_CanvasDrawableCoords(canvas, arcPtr->center2[0],
+ arcPtr->center2[1], &x2, &y2);
+
+ if (arcPtr->style == chordUid) {
+ XDrawLine(display, drawable, arcPtr->outlineGC,
+ x1, y1, x2, y2);
+ } else if (arcPtr->style == pieSliceUid) {
+ short cx, cy;
+
+ Tk_CanvasDrawableCoords(canvas,
+ (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0,
+ (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0, &cx, &cy);
+ XDrawLine(display, drawable, arcPtr->outlineGC,
+ cx, cy, x1, y1);
+ XDrawLine(display, drawable, arcPtr->outlineGC,
+ cx, cy, x2, y2);
+ }
+ } else {
+ if (arcPtr->style == chordUid) {
+ TkFillPolygon(canvas, arcPtr->outlinePtr, CHORD_OUTLINE_PTS,
+ display, drawable, arcPtr->outlineGC, None);
+ } else if (arcPtr->style == pieSliceUid) {
+ TkFillPolygon(canvas, arcPtr->outlinePtr, PIE_OUTLINE1_PTS,
+ display, drawable, arcPtr->outlineGC, None);
+ TkFillPolygon(canvas, arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
+ PIE_OUTLINE2_PTS, display, drawable, arcPtr->outlineGC,
+ None);
+ }
+ }
+ if (arcPtr->outlineStipple != None) {
+ XSetTSOrigin(display, arcPtr->outlineGC, 0, 0);
+ }
+ }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ArcToPoint --
+ *
+ * Computes the distance from a given point to a given
+ * arc, in canvas units.
+ *
+ * Results:
+ * The return value is 0 if the point whose x and y coordinates
+ * are coordPtr[0] and coordPtr[1] is inside the arc. If the
+ * point isn't inside the arc then the return value is the
+ * distance from the point to the arc. If itemPtr is filled,
+ * then anywhere in the interior is considered "inside"; if
+ * itemPtr isn't filled, then "inside" means only the area
+ * occupied by the outline.
+ *
+ * Side effects:
+ * None.
+ *
+ *--------------------------------------------------------------
+ */
+
+ /* ARGSUSED */
+static double
+ArcToPoint(canvas, itemPtr, pointPtr)
+ Tk_Canvas canvas; /* Canvas containing item. */
+ Tk_Item *itemPtr; /* Item to check against point. */
+ double *pointPtr; /* Pointer to x and y coordinates. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+ double vertex[2], pointAngle, diff, dist, newDist;
+ double poly[8], polyDist, width, t1, t2;
+ int filled, angleInRange;
+
+ /*
+ * See if the point is within the angular range of the arc.
+ * Remember, X angles are backwards from the way we'd normally
+ * think of them. Also, compensate for any eccentricity of
+ * the oval.
+ */
+
+ vertex[0] = (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0;
+ vertex[1] = (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0;
+ t1 = (pointPtr[1] - vertex[1])/(arcPtr->bbox[3] - arcPtr->bbox[1]);
+ t2 = (pointPtr[0] - vertex[0])/(arcPtr->bbox[2] - arcPtr->bbox[0]);
+ if ((t1 == 0.0) && (t2 == 0.0)) {
+ pointAngle = 0;
+ } else {
+ pointAngle = -atan2(t1, t2)*180/PI;
+ }
+ diff = pointAngle - arcPtr->start;
+ diff -= ((int) (diff/360.0) * 360.0);
+ if (diff < 0) {
+ diff += 360.0;
+ }
+ angleInRange = (diff <= arcPtr->extent) ||
+ ((arcPtr->extent < 0) && ((diff - 360.0) >= arcPtr->extent));
+
+ /*
+ * Now perform different tests depending on what kind of arc
+ * we're dealing with.
+ */
+
+ if (arcPtr->style == arcUid) {
+ if (angleInRange) {
+ return TkOvalToPoint(arcPtr->bbox, (double) arcPtr->width,
+ 0, pointPtr);
+ }
+ dist = hypot(pointPtr[0] - arcPtr->center1[0],
+ pointPtr[1] - arcPtr->center1[1]);
+ newDist = hypot(pointPtr[0] - arcPtr->center2[0],
+ pointPtr[1] - arcPtr->center2[1]);
+ if (newDist < dist) {
+ return newDist;
+ }
+ return dist;
+ }
+
+ if ((arcPtr->fillGC != None) || (arcPtr->outlineGC == None)) {
+ filled = 1;
+ } else {
+ filled = 0;
+ }
+ if (arcPtr->outlineGC == None) {
+ width = 0.0;
+ } else {
+ width = arcPtr->width;
+ }
+
+ if (arcPtr->style == pieSliceUid) {
+ if (width > 1.0) {
+ dist = TkPolygonToPoint(arcPtr->outlinePtr, PIE_OUTLINE1_PTS,
+ pointPtr);
+ newDist = TkPolygonToPoint(arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
+ PIE_OUTLINE2_PTS, pointPtr);
+ } else {
+ dist = TkLineToPoint(vertex, arcPtr->center1, pointPtr);
+ newDist = TkLineToPoint(vertex, arcPtr->center2, pointPtr);
+ }
+ if (newDist < dist) {
+ dist = newDist;
+ }
+ if (angleInRange) {
+ newDist = TkOvalToPoint(arcPtr->bbox, width, filled, pointPtr);
+ if (newDist < dist) {
+ dist = newDist;
+ }
+ }
+ return dist;
+ }
+
+ /*
+ * This is a chord-style arc. We have to deal specially with the
+ * triangular piece that represents the difference between a
+ * chord-style arc and a pie-slice arc (for small angles this piece
+ * is excluded here where it would be included for pie slices;
+ * for large angles the piece is included here but would be
+ * excluded for pie slices).
+ */
+
+ if (width > 1.0) {
+ dist = TkPolygonToPoint(arcPtr->outlinePtr, CHORD_OUTLINE_PTS,
+ pointPtr);
+ } else {
+ dist = TkLineToPoint(arcPtr->center1, arcPtr->center2, pointPtr);
+ }
+ poly[0] = poly[6] = vertex[0];
+ poly[1] = poly[7] = vertex[1];
+ poly[2] = arcPtr->center1[0];
+ poly[3] = arcPtr->center1[1];
+ poly[4] = arcPtr->center2[0];
+ poly[5] = arcPtr->center2[1];
+ polyDist = TkPolygonToPoint(poly, 4, pointPtr);
+ if (angleInRange) {
+ if ((arcPtr->extent < -180.0) || (arcPtr->extent > 180.0)
+ || (polyDist > 0.0)) {
+ newDist = TkOvalToPoint(arcPtr->bbox, width, filled, pointPtr);
+ if (newDist < dist) {
+ dist = newDist;
+ }
+ }
+ } else {
+ if ((arcPtr->extent < -180.0) || (arcPtr->extent > 180.0)) {
+ if (filled && (polyDist < dist)) {
+ dist = polyDist;
+ }
+ }
+ }
+ return dist;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ArcToArea --
+ *
+ * This procedure is called to determine whether an item
+ * lies entirely inside, entirely outside, or overlapping
+ * a given area.
+ *
+ * Results:
+ * -1 is returned if the item is entirely outside the area
+ * given by rectPtr, 0 if it overlaps, and 1 if it is entirely
+ * inside the given area.
+ *
+ * Side effects:
+ * None.
+ *
+ *--------------------------------------------------------------
+ */
+
+ /* ARGSUSED */
+static int
+ArcToArea(canvas, itemPtr, rectPtr)
+ Tk_Canvas canvas; /* Canvas containing item. */
+ Tk_Item *itemPtr; /* Item to check against arc. */
+ double *rectPtr; /* Pointer to array of four coordinates
+ * (x1, y1, x2, y2) describing rectangular
+ * area. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+ double rx, ry; /* Radii for transformed oval: these define
+ * an oval centered at the origin. */
+ double tRect[4]; /* Transformed version of x1, y1, x2, y2,
+ * for coord. system where arc is centered
+ * on the origin. */
+ double center[2], width, angle, tmp;
+ double points[20], *pointPtr;
+ int numPoints, filled;
+ int inside; /* Non-zero means every test so far suggests
+ * that arc is inside rectangle. 0 means
+ * every test so far shows arc to be outside
+ * of rectangle. */
+ int newInside;
+
+ if ((arcPtr->fillGC != None) || (arcPtr->outlineGC == None)) {
+ filled = 1;
+ } else {
+ filled = 0;
+ }
+ if (arcPtr->outlineGC == None) {
+ width = 0.0;
+ } else {
+ width = arcPtr->width;
+ }
+
+ /*
+ * Transform both the arc and the rectangle so that the arc's oval
+ * is centered on the origin.
+ */
+
+ center[0] = (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0;
+ center[1] = (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0;
+ tRect[0] = rectPtr[0] - center[0];
+ tRect[1] = rectPtr[1] - center[1];
+ tRect[2] = rectPtr[2] - center[0];
+ tRect[3] = rectPtr[3] - center[1];
+ rx = arcPtr->bbox[2] - center[0] + width/2.0;
+ ry = arcPtr->bbox[3] - center[1] + width/2.0;
+
+ /*
+ * Find the extreme points of the arc and see whether these are all
+ * inside the rectangle (in which case we're done), partly in and
+ * partly out (in which case we're done), or all outside (in which
+ * case we have more work to do). The extreme points include the
+ * following, which are checked in order:
+ *
+ * 1. The outside points of the arc, corresponding to start and
+ * extent.
+ * 2. The center of the arc (but only in pie-slice mode).
+ * 3. The 12, 3, 6, and 9-o'clock positions (but only if the arc
+ * includes those angles).
+ */
+
+ pointPtr = points;
+ angle = -arcPtr->start*(PI/180.0);
+ pointPtr[0] = rx*cos(angle);
+ pointPtr[1] = ry*sin(angle);
+ angle += -arcPtr->extent*(PI/180.0);
+ pointPtr[2] = rx*cos(angle);
+ pointPtr[3] = ry*sin(angle);
+ numPoints = 2;
+ pointPtr += 4;
+
+ if ((arcPtr->style == pieSliceUid) && (arcPtr->extent < 180.0)) {
+ pointPtr[0] = 0.0;
+ pointPtr[1] = 0.0;
+ numPoints++;
+ pointPtr += 2;
+ }
+
+ tmp = -arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ pointPtr[0] = rx;
+ pointPtr[1] = 0.0;
+ numPoints++;
+ pointPtr += 2;
+ }
+ tmp = 90.0 - arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ pointPtr[0] = 0.0;
+ pointPtr[1] = -ry;
+ numPoints++;
+ pointPtr += 2;
+ }
+ tmp = 180.0 - arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ pointPtr[0] = -rx;
+ pointPtr[1] = 0.0;
+ numPoints++;
+ pointPtr += 2;
+ }
+ tmp = 270.0 - arcPtr->start;
+ if (tmp < 0) {
+ tmp += 360.0;
+ }
+ if ((tmp < arcPtr->extent) || ((tmp-360) > arcPtr->extent)) {
+ pointPtr[0] = 0.0;
+ pointPtr[1] = ry;
+ numPoints++;
+ }
+
+ /*
+ * Now that we've located the extreme points, loop through them all
+ * to see which are inside the rectangle.
+ */
+
+ inside = (points[0] > tRect[0]) && (points[0] < tRect[2])
+ && (points[1] > tRect[1]) && (points[1] < tRect[3]);
+ for (pointPtr = points+2; numPoints > 1; pointPtr += 2, numPoints--) {
+ newInside = (pointPtr[0] > tRect[0]) && (pointPtr[0] < tRect[2])
+ && (pointPtr[1] > tRect[1]) && (pointPtr[1] < tRect[3]);
+ if (newInside != inside) {
+ return 0;
+ }
+ }
+
+ if (inside) {
+ return 1;
+ }
+
+ /*
+ * So far, oval appears to be outside rectangle, but can't yet tell
+ * for sure. Next, test each of the four sides of the rectangle
+ * against the bounding region for the arc. If any intersections
+ * are found, then return "overlapping". First, test against the
+ * polygon(s) forming the sides of a chord or pie-slice.
+ */
+
+ if (arcPtr->style == pieSliceUid) {
+ if (width >= 1.0) {
+ if (TkPolygonToArea(arcPtr->outlinePtr, PIE_OUTLINE1_PTS,
+ rectPtr) != -1) {
+ return 0;
+ }
+ if (TkPolygonToArea(arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
+ PIE_OUTLINE2_PTS, rectPtr) != -1) {
+ return 0;
+ }
+ } else {
+ if ((TkLineToArea(center, arcPtr->center1, rectPtr) != -1) ||
+ (TkLineToArea(center, arcPtr->center2, rectPtr) != -1)) {
+ return 0;
+ }
+ }
+ } else if (arcPtr->style == chordUid) {
+ if (width >= 1.0) {
+ if (TkPolygonToArea(arcPtr->outlinePtr, CHORD_OUTLINE_PTS,
+ rectPtr) != -1) {
+ return 0;
+ }
+ } else {
+ if (TkLineToArea(arcPtr->center1, arcPtr->center2,
+ rectPtr) != -1) {
+ return 0;
+ }
+ }
+ }
+
+ /*
+ * Next check for overlap between each of the four sides and the
+ * outer perimiter of the arc. If the arc isn't filled, then also
+ * check the inner perimeter of the arc.
+ */
+
+ if (HorizLineToArc(tRect[0], tRect[2], tRect[1], rx, ry, arcPtr->start,
+ arcPtr->extent)
+ || HorizLineToArc(tRect[0], tRect[2], tRect[3], rx, ry,
+ arcPtr->start, arcPtr->extent)
+ || VertLineToArc(tRect[0], tRect[1], tRect[3], rx, ry,
+ arcPtr->start, arcPtr->extent)
+ || VertLineToArc(tRect[2], tRect[1], tRect[3], rx, ry,
+ arcPtr->start, arcPtr->extent)) {
+ return 0;
+ }
+ if ((width > 1.0) && !filled) {
+ rx -= width;
+ ry -= width;
+ if (HorizLineToArc(tRect[0], tRect[2], tRect[1], rx, ry, arcPtr->start,
+ arcPtr->extent)
+ || HorizLineToArc(tRect[0], tRect[2], tRect[3], rx, ry,
+ arcPtr->start, arcPtr->extent)
+ || VertLineToArc(tRect[0], tRect[1], tRect[3], rx, ry,
+ arcPtr->start, arcPtr->extent)
+ || VertLineToArc(tRect[2], tRect[1], tRect[3], rx, ry,
+ arcPtr->start, arcPtr->extent)) {
+ return 0;
+ }
+ }
+
+ /*
+ * The arc still appears to be totally disjoint from the rectangle,
+ * but it's also possible that the rectangle is totally inside the arc.
+ * Do one last check, which is to check one point of the rectangle
+ * to see if it's inside the arc. If it is, we've got overlap. If
+ * it isn't, the arc's really outside the rectangle.
+ */
+
+ if (ArcToPoint(canvas, itemPtr, rectPtr) == 0.0) {
+ return 0;
+ }
+ return -1;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ScaleArc --
+ *
+ * This procedure is invoked to rescale an arc item.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The arc referred to by itemPtr is rescaled so that the
+ * following transformation is applied to all point
+ * coordinates:
+ * x' = originX + scaleX*(x-originX)
+ * y' = originY + scaleY*(y-originY)
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+ScaleArc(canvas, itemPtr, originX, originY, scaleX, scaleY)
+ Tk_Canvas canvas; /* Canvas containing arc. */
+ Tk_Item *itemPtr; /* Arc to be scaled. */
+ double originX, originY; /* Origin about which to scale rect. */
+ double scaleX; /* Amount to scale in X direction. */
+ double scaleY; /* Amount to scale in Y direction. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+
+ arcPtr->bbox[0] = originX + scaleX*(arcPtr->bbox[0] - originX);
+ arcPtr->bbox[1] = originY + scaleY*(arcPtr->bbox[1] - originY);
+ arcPtr->bbox[2] = originX + scaleX*(arcPtr->bbox[2] - originX);
+ arcPtr->bbox[3] = originY + scaleY*(arcPtr->bbox[3] - originY);
+ ComputeArcBbox(canvas, arcPtr);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TranslateArc --
+ *
+ * This procedure is called to move an arc by a given amount.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The position of the arc is offset by (xDelta, yDelta), and
+ * the bounding box is updated in the generic part of the item
+ * structure.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+TranslateArc(canvas, itemPtr, deltaX, deltaY)
+ Tk_Canvas canvas; /* Canvas containing item. */
+ Tk_Item *itemPtr; /* Item that is being moved. */
+ double deltaX, deltaY; /* Amount by which item is to be
+ * moved. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+
+ arcPtr->bbox[0] += deltaX;
+ arcPtr->bbox[1] += deltaY;
+ arcPtr->bbox[2] += deltaX;
+ arcPtr->bbox[3] += deltaY;
+ ComputeArcBbox(canvas, arcPtr);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ComputeArcOutline --
+ *
+ * This procedure creates a polygon describing everything in
+ * the outline for an arc except what's in the curved part.
+ * For a "pie slice" arc this is a V-shaped chunk, and for
+ * a "chord" arc this is a linear chunk (with cutaway corners).
+ * For "arc" arcs, this stuff isn't relevant.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The information at arcPtr->outlinePtr gets modified, and
+ * storage for arcPtr->outlinePtr may be allocated or freed.
+ *
+ *--------------------------------------------------------------
+ */
+
+static void
+ComputeArcOutline(arcPtr)
+ ArcItem *arcPtr; /* Information about arc. */
+{
+ double sin1, cos1, sin2, cos2, angle, halfWidth;
+ double boxWidth, boxHeight;
+ double vertex[2], corner1[2], corner2[2];
+ double *outlinePtr;
+
+ /*
+ * Make sure that the outlinePtr array is large enough to hold
+ * either a chord or pie-slice outline.
+ */
+
+ if (arcPtr->numOutlinePoints == 0) {
+ arcPtr->outlinePtr = (double *) ckalloc((unsigned)
+ (26 * sizeof(double)));
+ arcPtr->numOutlinePoints = 22;
+ }
+ outlinePtr = arcPtr->outlinePtr;
+
+ /*
+ * First compute the two points that lie at the centers of
+ * the ends of the curved arc segment, which are marked with
+ * X's in the figure below:
+ *
+ *
+ * * * *
+ * * *
+ * * * * *
+ * * * * *
+ * * * * *
+ * X * * X
+ *
+ * The code is tricky because the arc can be ovular in shape.
+ * It computes the position for a unit circle, and then
+ * scales to fit the shape of the arc's bounding box.
+ *
+ * Also, watch out because angles go counter-clockwise like you
+ * might expect, but the y-coordinate system is inverted. To
+ * handle this, just negate the angles in all the computations.
+ */
+
+ boxWidth = arcPtr->bbox[2] - arcPtr->bbox[0];
+ boxHeight = arcPtr->bbox[3] - arcPtr->bbox[1];
+ angle = -arcPtr->start*PI/180.0;
+ sin1 = sin(angle);
+ cos1 = cos(angle);
+ angle -= arcPtr->extent*PI/180.0;
+ sin2 = sin(angle);
+ cos2 = cos(angle);
+ vertex[0] = (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0;
+ vertex[1] = (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0;
+ arcPtr->center1[0] = vertex[0] + cos1*boxWidth/2.0;
+ arcPtr->center1[1] = vertex[1] + sin1*boxHeight/2.0;
+ arcPtr->center2[0] = vertex[0] + cos2*boxWidth/2.0;
+ arcPtr->center2[1] = vertex[1] + sin2*boxHeight/2.0;
+
+ /*
+ * Next compute the "outermost corners" of the arc, which are
+ * marked with X's in the figure below:
+ *
+ * * * *
+ * * *
+ * * * * *
+ * * * * *
+ * X * * X
+ * * *
+ *
+ * The code below is tricky because it has to handle eccentricity
+ * in the shape of the oval. The key in the code below is to
+ * realize that the slope of the line from arcPtr->center1 to corner1
+ * is (boxWidth*sin1)/(boxHeight*cos1), and similarly for arcPtr->center2
+ * and corner2. These formulas can be computed from the formula for
+ * the oval.
+ */
+
+ halfWidth = arcPtr->width/2.0;
+ if (((boxWidth*sin1) == 0.0) && ((boxHeight*cos1) == 0.0)) {
+ angle = 0.0;
+ } else {
+ angle = atan2(boxWidth*sin1, boxHeight*cos1);
+ }
+ corner1[0] = arcPtr->center1[0] + cos(angle)*halfWidth;
+ corner1[1] = arcPtr->center1[1] + sin(angle)*halfWidth;
+ if (((boxWidth*sin2) == 0.0) && ((boxHeight*cos2) == 0.0)) {
+ angle = 0.0;
+ } else {
+ angle = atan2(boxWidth*sin2, boxHeight*cos2);
+ }
+ corner2[0] = arcPtr->center2[0] + cos(angle)*halfWidth;
+ corner2[1] = arcPtr->center2[1] + sin(angle)*halfWidth;
+
+ /*
+ * For a chord outline, generate a six-sided polygon with three
+ * points for each end of the chord. The first and third points
+ * for each end are butt points generated on either side of the
+ * center point. The second point is the corner point.
+ */
+
+ if (arcPtr->style == chordUid) {
+ outlinePtr[0] = outlinePtr[12] = corner1[0];
+ outlinePtr[1] = outlinePtr[13] = corner1[1];
+ TkGetButtPoints(arcPtr->center2, arcPtr->center1,
+ (double) arcPtr->width, 0, outlinePtr+10, outlinePtr+2);
+ outlinePtr[4] = arcPtr->center2[0] + outlinePtr[2]
+ - arcPtr->center1[0];
+ outlinePtr[5] = arcPtr->center2[1] + outlinePtr[3]
+ - arcPtr->center1[1];
+ outlinePtr[6] = corner2[0];
+ outlinePtr[7] = corner2[1];
+ outlinePtr[8] = arcPtr->center2[0] + outlinePtr[10]
+ - arcPtr->center1[0];
+ outlinePtr[9] = arcPtr->center2[1] + outlinePtr[11]
+ - arcPtr->center1[1];
+ } else if (arcPtr->style == pieSliceUid) {
+ /*
+ * For pie slices, generate two polygons, one for each side
+ * of the pie slice. The first arm has a shape like this,
+ * where the center of the oval is X, arcPtr->center1 is at Y, and
+ * corner1 is at Z:
+ *
+ * _____________________
+ * | \
+ * | \
+ * X Y Z
+ * | /
+ * |_____________________/
+ *
+ */
+
+ TkGetButtPoints(arcPtr->center1, vertex, (double) arcPtr->width, 0,
+ outlinePtr, outlinePtr+2);
+ outlinePtr[4] = arcPtr->center1[0] + outlinePtr[2] - vertex[0];
+ outlinePtr[5] = arcPtr->center1[1] + outlinePtr[3] - vertex[1];
+ outlinePtr[6] = corner1[0];
+ outlinePtr[7] = corner1[1];
+ outlinePtr[8] = arcPtr->center1[0] + outlinePtr[0] - vertex[0];
+ outlinePtr[9] = arcPtr->center1[1] + outlinePtr[1] - vertex[1];
+ outlinePtr[10] = outlinePtr[0];
+ outlinePtr[11] = outlinePtr[1];
+
+ /*
+ * The second arm has a shape like this:
+ *
+ *
+ * ______________________
+ * / \
+ * / \
+ * Z Y X /
+ * \ /
+ * \______________________/
+ *
+ * Similar to above X is the center of the oval/circle, Y is
+ * arcPtr->center2, and Z is corner2. The extra jog out to the left
+ * of X is needed in or to produce a butted joint with the
+ * first arm; the corner to the right of X is one of the
+ * first two points of the first arm, depending on extent.
+ */
+
+ TkGetButtPoints(arcPtr->center2, vertex, (double) arcPtr->width, 0,
+ outlinePtr+12, outlinePtr+16);
+ if ((arcPtr->extent > 180) ||
+ ((arcPtr->extent < 0) && (arcPtr->extent > -180))) {
+ outlinePtr[14] = outlinePtr[0];
+ outlinePtr[15] = outlinePtr[1];
+ } else {
+ outlinePtr[14] = outlinePtr[2];
+ outlinePtr[15] = outlinePtr[3];
+ }
+ outlinePtr[18] = arcPtr->center2[0] + outlinePtr[16] - vertex[0];
+ outlinePtr[19] = arcPtr->center2[1] + outlinePtr[17] - vertex[1];
+ outlinePtr[20] = corner2[0];
+ outlinePtr[21] = corner2[1];
+ outlinePtr[22] = arcPtr->center2[0] + outlinePtr[12] - vertex[0];
+ outlinePtr[23] = arcPtr->center2[1] + outlinePtr[13] - vertex[1];
+ outlinePtr[24] = outlinePtr[12];
+ outlinePtr[25] = outlinePtr[13];
+ }
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * HorizLineToArc --
+ *
+ * Determines whether a horizontal line segment intersects
+ * a given arc.
+ *
+ * Results:
+ * The return value is 1 if the given line intersects the
+ * infinitely-thin arc section defined by rx, ry, start,
+ * and extent, and 0 otherwise. Only the perimeter of the
+ * arc is checked: interior areas (e.g. pie-slice or chord)
+ * are not checked.
+ *
+ * Side effects:
+ * None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+HorizLineToArc(x1, x2, y, rx, ry, start, extent)
+ double x1, x2; /* X-coords of endpoints of line segment.
+ * X1 must be <= x2. */
+ double y; /* Y-coordinate of line segment. */
+ double rx, ry; /* These x- and y-radii define an oval
+ * centered at the origin. */
+ double start, extent; /* Angles that define extent of arc, in
+ * the standard fashion for this module. */
+{
+ double tmp;
+ double tx, ty; /* Coordinates of intersection point in
+ * transformed coordinate system. */
+ double x;
+
+ /*
+ * Compute the x-coordinate of one possible intersection point
+ * between the arc and the line. Use a transformed coordinate
+ * system where the oval is a unit circle centered at the origin.
+ * Then scale back to get actual x-coordinate.
+ */
+
+ ty = y/ry;
+ tmp = 1 - ty*ty;
+ if (tmp < 0) {
+ return 0;
+ }
+ tx = sqrt(tmp);
+ x = tx*rx;
+
+ /*
+ * Test both intersection points.
+ */
+
+ if ((x >= x1) && (x <= x2) && AngleInRange(tx, ty, start, extent)) {
+ return 1;
+ }
+ if ((-x >= x1) && (-x <= x2) && AngleInRange(-tx, ty, start, extent)) {
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * VertLineToArc --
+ *
+ * Determines whether a vertical line segment intersects
+ * a given arc.
+ *
+ * Results:
+ * The return value is 1 if the given line intersects the
+ * infinitely-thin arc section defined by rx, ry, start,
+ * and extent, and 0 otherwise. Only the perimeter of the
+ * arc is checked: interior areas (e.g. pie-slice or chord)
+ * are not checked.
+ *
+ * Side effects:
+ * None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+VertLineToArc(x, y1, y2, rx, ry, start, extent)
+ double x; /* X-coordinate of line segment. */
+ double y1, y2; /* Y-coords of endpoints of line segment.
+ * Y1 must be <= y2. */
+ double rx, ry; /* These x- and y-radii define an oval
+ * centered at the origin. */
+ double start, extent; /* Angles that define extent of arc, in
+ * the standard fashion for this module. */
+{
+ double tmp;
+ double tx, ty; /* Coordinates of intersection point in
+ * transformed coordinate system. */
+ double y;
+
+ /*
+ * Compute the y-coordinate of one possible intersection point
+ * between the arc and the line. Use a transformed coordinate
+ * system where the oval is a unit circle centered at the origin.
+ * Then scale back to get actual y-coordinate.
+ */
+
+ tx = x/rx;
+ tmp = 1 - tx*tx;
+ if (tmp < 0) {
+ return 0;
+ }
+ ty = sqrt(tmp);
+ y = ty*ry;
+
+ /*
+ * Test both intersection points.
+ */
+
+ if ((y > y1) && (y < y2) && AngleInRange(tx, ty, start, extent)) {
+ return 1;
+ }
+ if ((-y > y1) && (-y < y2) && AngleInRange(tx, -ty, start, extent)) {
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * AngleInRange --
+ *
+ * Determine whether the angle from the origin to a given
+ * point is within a given range.
+ *
+ * Results:
+ * The return value is 1 if the angle from (0,0) to (x,y)
+ * is in the range given by start and extent, where angles
+ * are interpreted in the standard way for ovals (meaning
+ * backwards from normal interpretation). Otherwise the
+ * return value is 0.
+ *
+ * Side effects:
+ * None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+AngleInRange(x, y, start, extent)
+ double x, y; /* Coordinate of point; angle measured
+ * from origin to here, relative to x-axis. */
+ double start; /* First angle, degrees, >=0, <=360. */
+ double extent; /* Size of arc in degrees >=-360, <=360. */
+{
+ double diff;
+
+ if ((x == 0.0) && (y == 0.0)) {
+ return 1;
+ }
+ diff = -atan2(y, x);
+ diff = diff*(180.0/PI) - start;
+ while (diff > 360.0) {
+ diff -= 360.0;
+ }
+ while (diff < 0.0) {
+ diff += 360.0;
+ }
+ if (extent >= 0) {
+ return diff <= extent;
+ }
+ return (diff-360.0) >= extent;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ArcToPostscript --
+ *
+ * This procedure is called to generate Postscript for
+ * arc items.
+ *
+ * Results:
+ * The return value is a standard Tcl result. If an error
+ * occurs in generating Postscript then an error message is
+ * left in interp->result, replacing whatever used
+ * to be there. If no error occurs, then Postscript for the
+ * item is appended to the result.
+ *
+ * Side effects:
+ * None.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+ArcToPostscript(interp, canvas, itemPtr, prepass)
+ Tcl_Interp *interp; /* Leave Postscript or error message
+ * here. */
+ Tk_Canvas canvas; /* Information about overall canvas. */
+ Tk_Item *itemPtr; /* Item for which Postscript is
+ * wanted. */
+ int prepass; /* 1 means this is a prepass to
+ * collect font information; 0 means
+ * final Postscript is being created. */
+{
+ ArcItem *arcPtr = (ArcItem *) itemPtr;
+ char buffer[400];
+ double y1, y2, ang1, ang2;
+
+ y1 = Tk_CanvasPsY(canvas, arcPtr->bbox[1]);
+ y2 = Tk_CanvasPsY(canvas, arcPtr->bbox[3]);
+ ang1 = arcPtr->start;
+ ang2 = ang1 + arcPtr->extent;
+ if (ang2 < ang1) {
+ ang1 = ang2;
+ ang2 = arcPtr->start;
+ }
+
+ /*
+ * If the arc is filled, output Postscript for the interior region
+ * of the arc.
+ */
+
+ if (arcPtr->fillGC != None) {
+ sprintf(buffer, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale\n",
+ (arcPtr->bbox[0] + arcPtr->bbox[2])/2, (y1 + y2)/2,
+ (arcPtr->bbox[2] - arcPtr->bbox[0])/2, (y1 - y2)/2);
+ Tcl_AppendResult(interp, buffer, (char *) NULL);
+ if (arcPtr->style == chordUid) {
+ sprintf(buffer, "0 0 1 %.15g %.15g arc closepath\nsetmatrix\n",
+ ang1, ang2);
+ } else {
+ sprintf(buffer,
+ "0 0 moveto 0 0 1 %.15g %.15g arc closepath\nsetmatrix\n",
+ ang1, ang2);
+ }
+ Tcl_AppendResult(interp, buffer, (char *) NULL);
+ if (Tk_CanvasPsColor(interp, canvas, arcPtr->fillColor) != TCL_OK) {
+ return TCL_ERROR;
+ };
+ if (arcPtr->fillStipple != None) {
+ Tcl_AppendResult(interp, "clip ", (char *) NULL);
+ if (Tk_CanvasPsStipple(interp, canvas, arcPtr->fillStipple)
+ != TCL_OK) {
+ return TCL_ERROR;
+ }
+ if (arcPtr->outlineGC != None) {
+ Tcl_AppendResult(interp, "grestore gsave\n", (char *) NULL);
+ }
+ } else {
+ Tcl_AppendResult(interp, "fill\n", (char *) NULL);
+ }
+ }
+
+ /*
+ * If there's an outline for the arc, draw it.
+ */
+
+ if (arcPtr->outlineGC != None) {
+ sprintf(buffer, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale\n",
+ (arcPtr->bbox[0] + arcPtr->bbox[2])/2, (y1 + y2)/2,
+ (arcPtr->bbox[2] - arcPtr->bbox[0])/2, (y1 - y2)/2);
+ Tcl_AppendResult(interp, buffer, (char *) NULL);
+ sprintf(buffer, "0 0 1 %.15g %.15g arc\nsetmatrix\n", ang1, ang2);
+ Tcl_AppendResult(interp, buffer, (char *) NULL);
+ sprintf(buffer, "%d setlinewidth\n0 setlinecap\n", arcPtr->width);
+ Tcl_AppendResult(interp, buffer, (char *) NULL);
+ if (Tk_CanvasPsColor(interp, canvas, arcPtr->outlineColor)
+ != TCL_OK) {
+ return TCL_ERROR;
+ }
+ if (arcPtr->outlineStipple != None) {
+ Tcl_AppendResult(interp, "StrokeClip ", (char *) NULL);
+ if (Tk_CanvasPsStipple(interp, canvas,
+ arcPtr->outlineStipple) != TCL_OK) {
+ return TCL_ERROR;
+ }
+ } else {
+ Tcl_AppendResult(interp, "stroke\n", (char *) NULL);
+ }
+ if (arcPtr->style != arcUid) {
+ Tcl_AppendResult(interp, "grestore gsave\n", (char *) NULL);
+ if (arcPtr->style == chordUid) {
+ Tk_CanvasPsPath(interp, canvas, arcPtr->outlinePtr,
+ CHORD_OUTLINE_PTS);
+ } else {
+ Tk_CanvasPsPath(interp, canvas, arcPtr->outlinePtr,
+ PIE_OUTLINE1_PTS);
+ if (Tk_CanvasPsColor(interp, canvas, arcPtr->outlineColor)
+ != TCL_OK) {
+ return TCL_ERROR;
+ }
+ if (arcPtr->outlineStipple != None) {
+ Tcl_AppendResult(interp, "clip ", (char *) NULL);
+ if (Tk_CanvasPsStipple(interp, canvas,
+ arcPtr->outlineStipple) != TCL_OK) {
+ return TCL_ERROR;
+ }
+ } else {
+ Tcl_AppendResult(interp, "fill\n", (char *) NULL);
+ }
+ Tcl_AppendResult(interp, "grestore gsave\n", (char *) NULL);
+ Tk_CanvasPsPath(interp, canvas,
+ arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
+ PIE_OUTLINE2_PTS);
+ }
+ if (Tk_CanvasPsColor(interp, canvas, arcPtr->outlineColor)
+ != TCL_OK) {
+ return TCL_ERROR;
+ }
+ if (arcPtr->outlineStipple != None) {
+ Tcl_AppendResult(interp, "clip ", (char *) NULL);
+ if (Tk_CanvasPsStipple(interp, canvas,
+ arcPtr->outlineStipple) != TCL_OK) {
+ return TCL_ERROR;
+ }
+ } else {
+ Tcl_AppendResult(interp, "fill\n", (char *) NULL);
+ }
+ }
+ }
+
+ return TCL_OK;
+}