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stk/Tk/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 == pieSliceUid) {
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;
}
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