/* * tkCanvArc.c -- * * This file implements arc items for canvas widgets. * * Copyright (c) 1992-1993 The Regents of the University of California. * All rights reserved. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. */ #ifndef lint static char rcsid[] = "$Header: /user6/ouster/wish/RCS/tkCanvArc.c,v 1.16 93/09/15 08:19:59 ouster Exp $ SPRITE (Berkeley)"; #endif #include #include "tkConfig.h" #include "tkInt.h" #include "tkCanvas.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. */ Tk_Uid style; /* How to draw arc: arc, chord, or pieslice. */ GC outlineGC; /* Graphics context for outline. */ GC fillGC; /* Graphics context for filling item. */ GC *stippleGCPtr; /* If not NULL, points to a GC (either * outlineGC or fillGC) containing a stipple * offset that must be adjusted on each * redisplay. */ 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_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_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, &tkCanvasTagsOption}, {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 int ArcCoords _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, int argc, char **argv)); static int AngleInRange _ANSI_ARGS_((double x, double y, double start, double extent)); static int ArcToArea _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, double *rectPtr)); static double ArcToPoint _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, double *coordPtr)); static int ArcToPostscript _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, Tk_PostscriptInfo *psInfoPtr)); static void ComputeArcBbox _ANSI_ARGS_((Tk_Canvas *canvasPtr, ArcItem *arcPtr)); static void ComputeArcOutline _ANSI_ARGS_((ArcItem *arcPtr)); static int ConfigureArc _ANSI_ARGS_(( Tk_Canvas *canvasPtr, Tk_Item *itemPtr, int argc, char **argv, int flags)); static int CreateArc _ANSI_ARGS_((Tk_Canvas *canvasPtr, struct Tk_Item *itemPtr, int argc, char **argv)); static void DeleteArc _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr)); static void DisplayArc _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, Drawable dst)); static int HorizLineToArc _ANSI_ARGS_((double x1, double x2, double y, double rx, double ry, double start, double extent)); static void ScaleArc _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, double originX, double originY, double scaleX, double scaleY)); static void TranslateArc _ANSI_ARGS_((Tk_Canvas *canvasPtr, Tk_Item *itemPtr, double deltaX, double deltaY)); 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 * canvasPtr->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(canvasPtr, itemPtr, argc, argv) register Tk_Canvas *canvasPtr; /* 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. */ { register ArcItem *arcPtr = (ArcItem *) itemPtr; if (argc < 4) { Tcl_AppendResult(canvasPtr->interp, "wrong # args: should be \"", Tk_PathName(canvasPtr->tkwin), "\" 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->style = pieSliceUid; arcPtr->outlineGC = None; arcPtr->fillGC = None; arcPtr->stippleGCPtr = NULL; /* * Process the arguments to fill in the item record. */ if ((TkGetCanvasCoord(canvasPtr, argv[0], &arcPtr->bbox[0]) != TCL_OK) || (TkGetCanvasCoord(canvasPtr, argv[1], &arcPtr->bbox[1]) != TCL_OK) || (TkGetCanvasCoord(canvasPtr, argv[2], &arcPtr->bbox[2]) != TCL_OK) || (TkGetCanvasCoord(canvasPtr, argv[3], &arcPtr->bbox[3]) != TCL_OK)) { return TCL_ERROR; } if (ConfigureArc(canvasPtr, itemPtr, argc-4, argv+4, 0) != TCL_OK) { DeleteArc(canvasPtr, itemPtr); 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 canvasPtr->interp->result. * * Side effects: * The coordinates for the given item may be changed. * *-------------------------------------------------------------- */ static int ArcCoords(canvasPtr, itemPtr, argc, argv) register Tk_Canvas *canvasPtr; /* 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, ... */ { register 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(canvasPtr->interp, arcPtr->bbox[0], c0); Tcl_PrintDouble(canvasPtr->interp, arcPtr->bbox[1], c1); Tcl_PrintDouble(canvasPtr->interp, arcPtr->bbox[2], c2); Tcl_PrintDouble(canvasPtr->interp, arcPtr->bbox[3], c3); Tcl_AppendResult(canvasPtr->interp, c0, " ", c1, " ", c2, " ", c3, (char *) NULL); } else if (argc == 4) { if ((TkGetCanvasCoord(canvasPtr, argv[0], &arcPtr->bbox[0]) != TCL_OK) || (TkGetCanvasCoord(canvasPtr, argv[1], &arcPtr->bbox[1]) != TCL_OK) || (TkGetCanvasCoord(canvasPtr, argv[2], &arcPtr->bbox[2]) != TCL_OK) || (TkGetCanvasCoord(canvasPtr, argv[3], &arcPtr->bbox[3]) != TCL_OK)) { return TCL_ERROR; } ComputeArcBbox(canvasPtr, arcPtr); } else { sprintf(canvasPtr->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 canvasPtr->interp->result. * * Side effects: * Configuration information, such as colors and stipple * patterns, may be set for itemPtr. * *-------------------------------------------------------------- */ static int ConfigureArc(canvasPtr, itemPtr, argc, argv, flags) Tk_Canvas *canvasPtr; /* 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. */ { register ArcItem *arcPtr = (ArcItem *) itemPtr; XGCValues gcValues; GC newGC; unsigned long mask; int i; if (Tk_ConfigureWidget(canvasPtr->interp, canvasPtr->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 = arcPtr->start/360.0; arcPtr->start -= i*360.0; if (arcPtr->start < 0) { arcPtr->start += 360.0; } i = arcPtr->extent/360.0; arcPtr->extent -= i*360.0; if ((arcPtr->style != arcUid) && (arcPtr->style != chordUid) && (arcPtr->style != pieSliceUid)) { Tcl_AppendResult(canvasPtr->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; } arcPtr->stippleGCPtr = NULL; if (arcPtr->style == arcUid) { if (arcPtr->fillColor == NULL) { newGC = None; } else { gcValues.foreground = arcPtr->fillColor->pixel; gcValues.cap_style = CapButt; gcValues.line_width = arcPtr->width; mask = GCForeground|GCCapStyle|GCLineWidth; if (arcPtr->fillStipple != None) { gcValues.stipple = arcPtr->fillStipple; gcValues.fill_style = FillStippled; mask |= GCStipple|GCFillStyle; arcPtr->stippleGCPtr = &arcPtr->outlineGC; } newGC = Tk_GetGC(canvasPtr->tkwin, mask, &gcValues); } } else 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; newGC = Tk_GetGC(canvasPtr->tkwin, mask, &gcValues); } if (arcPtr->outlineGC != None) { Tk_FreeGC(canvasPtr->display, 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; arcPtr->stippleGCPtr = &arcPtr->fillGC; } newGC = Tk_GetGC(canvasPtr->tkwin, mask, &gcValues); } if (arcPtr->fillGC != None) { Tk_FreeGC(canvasPtr->display, arcPtr->fillGC); } arcPtr->fillGC = newGC; ComputeArcBbox(canvasPtr, 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(canvasPtr, itemPtr) Tk_Canvas *canvasPtr; /* Info about overall canvas. */ Tk_Item *itemPtr; /* Item that is being deleted. */ { register 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(canvasPtr->display, arcPtr->fillStipple); } if (arcPtr->outlineGC != None) { Tk_FreeGC(canvasPtr->display, arcPtr->outlineGC); } if (arcPtr->fillGC != None) { Tk_FreeGC(canvasPtr->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(canvasPtr, arcPtr) register Tk_Canvas *canvasPtr; /* Canvas that contains item. */ register 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 = arcPtr->center1[0]; arcPtr->header.y1 = arcPtr->header.y2 = arcPtr->center1[1]; TkIncludePoint(canvasPtr, (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(canvasPtr, (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(canvasPtr, (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(canvasPtr, (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(canvasPtr, (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(canvasPtr, (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 -= tmp; arcPtr->header.y1 -= tmp; arcPtr->header.x2 += tmp; arcPtr->header.y2 += 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 canvasPtr. * *-------------------------------------------------------------- */ static void DisplayArc(canvasPtr, itemPtr, drawable) register Tk_Canvas *canvasPtr; /* Canvas that contains item. */ Tk_Item *itemPtr; /* Item to be displayed. */ Drawable drawable; /* Pixmap or window in which to draw * item. */ { register ArcItem *arcPtr = (ArcItem *) itemPtr; Display *display = Tk_Display(canvasPtr->tkwin); int x1, y1, x2, y2, start, extent; /* * Compute the screen coordinates of the bounding box for the item, * plus integer values for the angles. */ x1 = SCREEN_X(canvasPtr, arcPtr->bbox[0]); y1 = SCREEN_Y(canvasPtr, arcPtr->bbox[1]); x2 = SCREEN_X(canvasPtr, arcPtr->bbox[2]); y2 = SCREEN_Y(canvasPtr, arcPtr->bbox[3]); if (x2 <= x1) { x2 = x1+1; } if (y2 <= y1) { y2 = y1+1; } start = (64*arcPtr->start) + 0.5; extent = (64*arcPtr->extent) + 0.5; /* * If the arc is being filled with a stipple pattern, modify the * stipple offset in the GC. Be sure to reset the offset when done, * since the GC is supposed to be read-only. */ if (arcPtr->stippleGCPtr != NULL) { XSetTSOrigin(display, *arcPtr->stippleGCPtr, -canvasPtr->drawableXOrigin, -canvasPtr->drawableYOrigin); } /* * 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)) { XFillArc(display, drawable, arcPtr->fillGC, x1, y1, (x2-x1), (y2-y1), start, extent); if (arcPtr->fillStipple != None) { XSetTSOrigin(display, arcPtr->fillGC, 0, 0); } } if (arcPtr->outlineGC != None) { if (extent != 0) { XDrawArc(display, drawable, arcPtr->outlineGC, x1, y1, (x2-x1), (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) { x1 = SCREEN_X(canvasPtr, arcPtr->center1[0]); y1 = SCREEN_Y(canvasPtr, arcPtr->center1[1]); x2 = SCREEN_X(canvasPtr, arcPtr->center2[0]); y2 = SCREEN_Y(canvasPtr, arcPtr->center2[1]); if (arcPtr->style == chordUid) { XDrawLine(display, drawable, arcPtr->outlineGC, x1, y1, x2, y2); } else if (arcPtr->style == pieSliceUid) { int cx, cy; cx = SCREEN_X(canvasPtr, (arcPtr->bbox[0] + arcPtr->bbox[2])/2.0); cy = SCREEN_Y(canvasPtr, (arcPtr->bbox[1] + arcPtr->bbox[3])/2.0); XDrawLine(display, drawable, arcPtr->outlineGC, cx, cy, x1, y1); XDrawLine(display, drawable, arcPtr->outlineGC, cx, cy, x2, y2); } } else { if (arcPtr->style == chordUid) { TkFillPolygon(canvasPtr, arcPtr->outlinePtr, CHORD_OUTLINE_PTS, drawable, arcPtr->outlineGC); } else if (arcPtr->style == pieSliceUid) { TkFillPolygon(canvasPtr, arcPtr->outlinePtr, PIE_OUTLINE1_PTS, drawable, arcPtr->outlineGC); TkFillPolygon(canvasPtr, arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS, PIE_OUTLINE2_PTS, drawable, arcPtr->outlineGC); } } } if (arcPtr->stippleGCPtr != NULL) { XSetTSOrigin(display, *arcPtr->stippleGCPtr, 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(canvasPtr, itemPtr, pointPtr) Tk_Canvas *canvasPtr; /* Canvas containing item. */ Tk_Item *itemPtr; /* Item to check against point. */ double *pointPtr; /* Pointer to x and y coordinates. */ { register ArcItem *arcPtr = (ArcItem *) itemPtr; double vertex[2], pointAngle, diff, dist, newDist; double poly[8], polyDist, width, t1, t2; int filled, angleInRange; if ((arcPtr->fillGC != None) || (arcPtr->outlineGC == None)) { filled = 1; } else { filled = 0; } /* * 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(canvasPtr, itemPtr, rectPtr) Tk_Canvas *canvasPtr; /* 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. */ { register 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; numPoints = 0; 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++; pointPtr += 2; } /* * 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(canvasPtr, 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(canvasPtr, itemPtr, originX, originY, scaleX, scaleY) Tk_Canvas *canvasPtr; /* 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. */ { register 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(canvasPtr, 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(canvasPtr, itemPtr, deltaX, deltaY) Tk_Canvas *canvasPtr; /* Canvas containing item. */ Tk_Item *itemPtr; /* Item that is being moved. */ double deltaX, deltaY; /* Amount by which item is to be * moved. */ { register ArcItem *arcPtr = (ArcItem *) itemPtr; arcPtr->bbox[0] += deltaX; arcPtr->bbox[1] += deltaY; arcPtr->bbox[2] += deltaX; arcPtr->bbox[3] += deltaY; ComputeArcBbox(canvasPtr, 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) register ArcItem *arcPtr; { 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; angle = atan2(boxWidth*sin1, boxHeight*cos1); corner1[0] = arcPtr->center1[0] + cos(angle)*halfWidth; corner1[1] = arcPtr->center1[1] + sin(angle)*halfWidth; 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; diff = -atan2(y, x); if ((x == 0.0) && (y == 0.0)) { return 1; } 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 canvasPtr->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(canvasPtr, itemPtr, psInfoPtr) Tk_Canvas *canvasPtr; /* Information about overall canvas. */ Tk_Item *itemPtr; /* Item for which Postscript is * wanted. */ Tk_PostscriptInfo *psInfoPtr; /* Information about the Postscript; * must be passed back to Postscript * utility procedures. */ { register ArcItem *arcPtr = (ArcItem *) itemPtr; char buffer[400]; double y1, y2, ang1, ang2; y1 = TkCanvPsY(psInfoPtr, arcPtr->bbox[1]); y2 = TkCanvPsY(psInfoPtr, 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(canvasPtr->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(canvasPtr->interp, buffer, (char *) NULL); if (TkCanvPsColor(canvasPtr, psInfoPtr, arcPtr->fillColor) != TCL_OK) { return TCL_ERROR; }; if (arcPtr->fillStipple != None) { if (TkCanvPsStipple(canvasPtr, psInfoPtr, arcPtr->fillStipple, 1) != TCL_OK) { return TCL_ERROR; } } else { Tcl_AppendResult(canvasPtr->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(canvasPtr->interp, buffer, (char *) NULL); sprintf(buffer, "0 0 1 %.15g %.15g arc\nsetmatrix\n", ang1, ang2); Tcl_AppendResult(canvasPtr->interp, buffer, (char *) NULL); sprintf(buffer, "%d setlinewidth\n0 setlinecap\n", arcPtr->width); Tcl_AppendResult(canvasPtr->interp, buffer, (char *) NULL); if (arcPtr->style == arcUid) { if (TkCanvPsColor(canvasPtr, psInfoPtr, arcPtr->fillColor) != TCL_OK) { return TCL_ERROR; }; if (arcPtr->fillStipple != None) { if (TkCanvPsStipple(canvasPtr, psInfoPtr, arcPtr->fillStipple, 0) != TCL_OK) { return TCL_ERROR; } } else { Tcl_AppendResult(canvasPtr->interp, "stroke\n", (char *) NULL); } } else { if (TkCanvPsColor(canvasPtr, psInfoPtr, arcPtr->outlineColor) != TCL_OK) { return TCL_ERROR; }; Tcl_AppendResult(canvasPtr->interp, "stroke\n", (char *) NULL); if (arcPtr->style == chordUid) { TkCanvPsPath(canvasPtr->interp, arcPtr->outlinePtr, CHORD_OUTLINE_PTS, psInfoPtr); Tcl_AppendResult(canvasPtr->interp, "fill\n", (char *) NULL); } else { TkCanvPsPath(canvasPtr->interp, arcPtr->outlinePtr, PIE_OUTLINE1_PTS, psInfoPtr); Tcl_AppendResult(canvasPtr->interp, "fill\n", (char *) NULL); TkCanvPsPath(canvasPtr->interp, arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS, PIE_OUTLINE2_PTS, psInfoPtr); Tcl_AppendResult(canvasPtr->interp, "fill\n", (char *) NULL); } } } return TCL_OK; }