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tkRectOval.c

/* 
 * tkRectOval.c --
 *
 *    This file implements rectangle and oval items for canvas
 *    widgets.
 *
 * Copyright (c) 1991-1994 The Regents of the University of California.
 * Copyright (c) 1994-1996 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tkRectOval.c,v 1.2 1998/09/14 18:23:16 stanton Exp $
 */

#include <stdio.h>
#include "tk.h"
#include "tkInt.h"
#include "tkPort.h"

/*
 * The structure below defines the record for each rectangle/oval item.
 */

typedef struct RectOvalItem  {
    Tk_Item header;           /* Generic stuff that's the same for all
                         * types.  MUST BE FIRST IN STRUCTURE. */
    double bbox[4];           /* Coordinates of bounding box for rectangle
                         * or oval (x1, y1, x2, y2).  Item includes
                         * x1 and x2 but not y1 and y2. */
    int width;                /* Width of outline. */
    XColor *outlineColor;     /* Color for outline. */
    XColor *fillColor;        /* Color for filling rectangle/oval. */
    Pixmap fillStipple;       /* Stipple bitmap for filling item. */
    GC outlineGC;       /* Graphics context for outline. */
    GC fillGC;                /* Graphics context for filling item. */
} RectOvalItem;

/*
 * Information used for parsing configuration specs:
 */

static Tk_CustomOption tagsOption = {Tk_CanvasTagsParseProc,
    Tk_CanvasTagsPrintProc, (ClientData) NULL
};

static Tk_ConfigSpec configSpecs[] = {
    {TK_CONFIG_COLOR, "-fill", (char *) NULL, (char *) NULL,
      (char *) NULL, Tk_Offset(RectOvalItem, fillColor), TK_CONFIG_NULL_OK},
    {TK_CONFIG_COLOR, "-outline", (char *) NULL, (char *) NULL,
      "black", Tk_Offset(RectOvalItem, outlineColor), TK_CONFIG_NULL_OK},
    {TK_CONFIG_BITMAP, "-stipple", (char *) NULL, (char *) NULL,
      (char *) NULL, Tk_Offset(RectOvalItem, fillStipple), TK_CONFIG_NULL_OK},
    {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(RectOvalItem, 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       ComputeRectOvalBbox _ANSI_ARGS_((Tk_Canvas canvas,
                      RectOvalItem *rectOvalPtr));
static int        ConfigureRectOval _ANSI_ARGS_((Tcl_Interp *interp,
                      Tk_Canvas canvas, Tk_Item *itemPtr, int argc,
                      char **argv, int flags));
static int        CreateRectOval _ANSI_ARGS_((Tcl_Interp *interp,
                      Tk_Canvas canvas, struct Tk_Item *itemPtr,
                      int argc, char **argv));
static void       DeleteRectOval _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, Display *display));
static void       DisplayRectOval _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, Display *display, Drawable dst,
                      int x, int y, int width, int height));
static int        OvalToArea _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, double *areaPtr));
static double           OvalToPoint _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, double *pointPtr));
static int        RectOvalCoords _ANSI_ARGS_((Tcl_Interp *interp,
                      Tk_Canvas canvas, Tk_Item *itemPtr, int argc,
                      char **argv));
static int        RectOvalToPostscript _ANSI_ARGS_((Tcl_Interp *interp,
                      Tk_Canvas canvas, Tk_Item *itemPtr, int prepass));
static int        RectToArea _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, double *areaPtr));
static double           RectToPoint _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, double *pointPtr));
static void       ScaleRectOval _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, double originX, double originY,
                      double scaleX, double scaleY));
static void       TranslateRectOval _ANSI_ARGS_((Tk_Canvas canvas,
                      Tk_Item *itemPtr, double deltaX, double deltaY));

/*
 * The structures below defines the rectangle and oval item types
 * by means of procedures that can be invoked by generic item code.
 */

Tk_ItemType tkRectangleType = {
    "rectangle",              /* name */
    sizeof(RectOvalItem),           /* itemSize */
    CreateRectOval,                 /* createProc */
    configSpecs,              /* configSpecs */
    ConfigureRectOval,              /* configureProc */
    RectOvalCoords,                 /* coordProc */
    DeleteRectOval,                 /* deleteProc */
    DisplayRectOval,                /* displayProc */
    0,                              /* alwaysRedraw */
    RectToPoint,              /* pointProc */
    RectToArea,                     /* areaProc */
    RectOvalToPostscript,           /* postscriptProc */
    ScaleRectOval,                  /* scaleProc */
    TranslateRectOval,              /* 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 */
};

Tk_ItemType tkOvalType = {
    "oval",                   /* name */
    sizeof(RectOvalItem),           /* itemSize */
    CreateRectOval,                 /* createProc */
    configSpecs,              /* configSpecs */
    ConfigureRectOval,              /* configureProc */
    RectOvalCoords,                 /* coordProc */
    DeleteRectOval,                 /* deleteProc */
    DisplayRectOval,                /* displayProc */
    0,                              /* alwaysRedraw */
    OvalToPoint,              /* pointProc */
    OvalToArea,                     /* areaProc */
    RectOvalToPostscript,           /* postscriptProc */
    ScaleRectOval,                  /* scaleProc */
    TranslateRectOval,              /* translateProc */
    (Tk_ItemIndexProc *) NULL,            /* indexProc */
    (Tk_ItemCursorProc *) NULL,           /* cursorProc */
    (Tk_ItemSelectionProc *) NULL,  /* selectionProc */
    (Tk_ItemInsertProc *) NULL,           /* insertProc */
    (Tk_ItemDCharsProc *) NULL,           /* dTextProc */
    (Tk_ItemType *) NULL            /* nextPtr */
};

/*
 *--------------------------------------------------------------
 *
 * CreateRectOval --
 *
 *    This procedure is invoked to create a new rectangle
 *    or oval 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 rectangle or oval item is created.
 *
 *--------------------------------------------------------------
 */

static int
CreateRectOval(interp, canvas, itemPtr, argc, argv)
    Tcl_Interp *interp;             /* 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 rectangle. */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) 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 initialization that is needed in order to clean
     * up after errors during the the remainder of this procedure.
     */

    rectOvalPtr->width = 1;
    rectOvalPtr->outlineColor = NULL;
    rectOvalPtr->fillColor = NULL;
    rectOvalPtr->fillStipple = None;
    rectOvalPtr->outlineGC = None;
    rectOvalPtr->fillGC = None;

    /*
     * Process the arguments to fill in the item record.
     */

    if ((Tk_CanvasGetCoord(interp, canvas, argv[0],
            &rectOvalPtr->bbox[0]) != TCL_OK)
          || (Tk_CanvasGetCoord(interp, canvas, argv[1],
            &rectOvalPtr->bbox[1]) != TCL_OK)
          || (Tk_CanvasGetCoord(interp, canvas, argv[2],
                &rectOvalPtr->bbox[2]) != TCL_OK)
          || (Tk_CanvasGetCoord(interp, canvas, argv[3],
                &rectOvalPtr->bbox[3]) != TCL_OK)) {
      return TCL_ERROR;
    }

    if (ConfigureRectOval(interp, canvas, itemPtr, argc-4, argv+4, 0)
          != TCL_OK) {
      DeleteRectOval(canvas, itemPtr, Tk_Display(Tk_CanvasTkwin(canvas)));
      return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * RectOvalCoords --
 *
 *    This procedure is invoked to process the "coords" widget
 *    command on rectangles and ovals.  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
RectOvalCoords(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, ... */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) 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, rectOvalPtr->bbox[0], c0);
      Tcl_PrintDouble(interp, rectOvalPtr->bbox[1], c1);
      Tcl_PrintDouble(interp, rectOvalPtr->bbox[2], c2);
      Tcl_PrintDouble(interp, rectOvalPtr->bbox[3], c3);
      Tcl_AppendResult(interp, c0, " ", c1, " ", c2, " ", c3,
            (char *) NULL);
    } else if (argc == 4) {
      if ((Tk_CanvasGetCoord(interp, canvas, argv[0],
                &rectOvalPtr->bbox[0]) != TCL_OK)
            || (Tk_CanvasGetCoord(interp, canvas, argv[1],
                &rectOvalPtr->bbox[1]) != TCL_OK)
            || (Tk_CanvasGetCoord(interp, canvas, argv[2],
                  &rectOvalPtr->bbox[2]) != TCL_OK)
            || (Tk_CanvasGetCoord(interp, canvas, argv[3],
                  &rectOvalPtr->bbox[3]) != TCL_OK)) {
          return TCL_ERROR;
      }
      ComputeRectOvalBbox(canvas, rectOvalPtr);
    } else {
      sprintf(interp->result,
            "wrong # coordinates: expected 0 or 4, got %d",
            argc);
      return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ConfigureRectOval --
 *
 *    This procedure is invoked to configure various aspects
 *    of a rectangle or oval item, such as its border and
 *    background 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
ConfigureRectOval(interp, canvas, itemPtr, argc, argv, flags)
    Tcl_Interp *interp;       /* Used for error reporting. */
    Tk_Canvas canvas;         /* Canvas containing itemPtr. */
    Tk_Item *itemPtr;         /* Rectangle 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. */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;
    XGCValues gcValues;
    GC newGC;
    unsigned long mask;
    Tk_Window tkwin;

    tkwin = Tk_CanvasTkwin(canvas);
    if (Tk_ConfigureWidget(interp, tkwin, configSpecs, argc, argv,
          (char *) rectOvalPtr, flags) != TCL_OK) {
      return TCL_ERROR;
    }

    /*
     * A few of the options require additional processing, such as
     * graphics contexts.
     */

    if (rectOvalPtr->width < 1) {
      rectOvalPtr->width = 1;
    }
    if (rectOvalPtr->outlineColor == NULL) {
      newGC = None;
    } else {
      gcValues.foreground = rectOvalPtr->outlineColor->pixel;
      gcValues.cap_style = CapProjecting;
      gcValues.line_width = rectOvalPtr->width;
      mask = GCForeground|GCCapStyle|GCLineWidth;
      newGC = Tk_GetGC(tkwin, mask, &gcValues);
    }
    if (rectOvalPtr->outlineGC != None) {
      Tk_FreeGC(Tk_Display(tkwin), rectOvalPtr->outlineGC);
    }
    rectOvalPtr->outlineGC = newGC;

    if (rectOvalPtr->fillColor == NULL) {
      newGC = None;
    } else {
      gcValues.foreground = rectOvalPtr->fillColor->pixel;
      if (rectOvalPtr->fillStipple != None) {
          gcValues.stipple = rectOvalPtr->fillStipple;
          gcValues.fill_style = FillStippled;
          mask = GCForeground|GCStipple|GCFillStyle;
      } else {
          mask = GCForeground;
      }
      newGC = Tk_GetGC(tkwin, mask, &gcValues);
    }
    if (rectOvalPtr->fillGC != None) {
      Tk_FreeGC(Tk_Display(tkwin), rectOvalPtr->fillGC);
    }
    rectOvalPtr->fillGC = newGC;
    ComputeRectOvalBbox(canvas, rectOvalPtr);

    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * DeleteRectOval --
 *
 *    This procedure is called to clean up the data structure
 *    associated with a rectangle or oval item.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Resources associated with itemPtr are released.
 *
 *--------------------------------------------------------------
 */

static void
DeleteRectOval(canvas, itemPtr, display)
    Tk_Canvas canvas;               /* Info about overall widget. */
    Tk_Item *itemPtr;               /* Item that is being deleted. */
    Display *display;               /* Display containing window for
                               * canvas. */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;

    if (rectOvalPtr->outlineColor != NULL) {
      Tk_FreeColor(rectOvalPtr->outlineColor);
    }
    if (rectOvalPtr->fillColor != NULL) {
      Tk_FreeColor(rectOvalPtr->fillColor);
    }
    if (rectOvalPtr->fillStipple != None) {
      Tk_FreeBitmap(display, rectOvalPtr->fillStipple);
    }
    if (rectOvalPtr->outlineGC != None) {
      Tk_FreeGC(display, rectOvalPtr->outlineGC);
    }
    if (rectOvalPtr->fillGC != None) {
      Tk_FreeGC(display, rectOvalPtr->fillGC);
    }
}

/*
 *--------------------------------------------------------------
 *
 * ComputeRectOvalBbox --
 *
 *    This procedure is invoked to compute the bounding box of
 *    all the pixels that may be drawn as part of a rectangle
 *    or oval.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    The fields x1, y1, x2, and y2 are updated in the header
 *    for itemPtr.
 *
 *--------------------------------------------------------------
 */

      /* ARGSUSED */
static void
ComputeRectOvalBbox(canvas, rectOvalPtr)
    Tk_Canvas canvas;               /* Canvas that contains item. */
    RectOvalItem *rectOvalPtr;            /* Item whose bbox is to be
                               * recomputed. */
{
    int bloat, tmp;
    double dtmp;

    /*
     * Make sure that the first coordinates are the lowest ones.
     */

    if (rectOvalPtr->bbox[1] > rectOvalPtr->bbox[3]) {
      double tmp;
      tmp = rectOvalPtr->bbox[3];
      rectOvalPtr->bbox[3] = rectOvalPtr->bbox[1];
      rectOvalPtr->bbox[1] = tmp;
    }
    if (rectOvalPtr->bbox[0] > rectOvalPtr->bbox[2]) {
      double tmp;
      tmp = rectOvalPtr->bbox[2];
      rectOvalPtr->bbox[2] = rectOvalPtr->bbox[0];
      rectOvalPtr->bbox[0] = tmp;
    }

    if (rectOvalPtr->outlineColor == NULL) {
      bloat = 0;
    } else {
      bloat = (rectOvalPtr->width+1)/2;
    }

    /*
     * Special note:  the rectangle is always drawn at least 1x1 in
     * size, so round up the upper coordinates to be at least 1 unit
     * greater than the lower ones.
     */

    tmp = (int) ((rectOvalPtr->bbox[0] >= 0) ? rectOvalPtr->bbox[0] + .5
          : rectOvalPtr->bbox[0] - .5);
    rectOvalPtr->header.x1 = tmp - bloat;
    tmp = (int) ((rectOvalPtr->bbox[1] >= 0) ? rectOvalPtr->bbox[1] + .5
          : rectOvalPtr->bbox[1] - .5);
    rectOvalPtr->header.y1 = tmp - bloat;
    dtmp = rectOvalPtr->bbox[2];
    if (dtmp < (rectOvalPtr->bbox[0] + 1)) {
      dtmp = rectOvalPtr->bbox[0] + 1;
    }
    tmp = (int) ((dtmp >= 0) ? dtmp + .5 : dtmp - .5);
    rectOvalPtr->header.x2 = tmp + bloat;
    dtmp = rectOvalPtr->bbox[3];
    if (dtmp < (rectOvalPtr->bbox[1] + 1)) {
      dtmp = rectOvalPtr->bbox[1] + 1;
    }
    tmp = (int) ((dtmp >= 0) ? dtmp + .5 : dtmp - .5);
    rectOvalPtr->header.y2 = tmp + bloat;
}

/*
 *--------------------------------------------------------------
 *
 * DisplayRectOval --
 *
 *    This procedure is invoked to draw a rectangle or oval
 *    item in a given drawable.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    ItemPtr is drawn in drawable using the transformation
 *    information in canvas.
 *
 *--------------------------------------------------------------
 */

static void
DisplayRectOval(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). */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;
    short x1, y1, x2, y2;

    /*
     * Compute the screen coordinates of the bounding box for the item.
     * Make sure that the bbox is at least one pixel large, since some
     * X servers will die if it isn't.
     */

    Tk_CanvasDrawableCoords(canvas, rectOvalPtr->bbox[0], rectOvalPtr->bbox[1],
          &x1, &y1);
    Tk_CanvasDrawableCoords(canvas, rectOvalPtr->bbox[2], rectOvalPtr->bbox[3],
          &x2, &y2);
    if (x2 <= x1) {
      x2 = x1+1;
    }
    if (y2 <= y1) {
      y2 = y1+1;
    }

    /*
     * Display filled part first (if wanted), then outline.  If we're
     * stippling, then 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 (rectOvalPtr->fillGC != None) {
      if (rectOvalPtr->fillStipple != None) {
          Tk_CanvasSetStippleOrigin(canvas, rectOvalPtr->fillGC);
      }
      if (rectOvalPtr->header.typePtr == &tkRectangleType) {
          XFillRectangle(display, drawable, rectOvalPtr->fillGC,
                x1, y1, (unsigned int) (x2-x1), (unsigned int) (y2-y1));
      } else {
          XFillArc(display, drawable, rectOvalPtr->fillGC,
                x1, y1, (unsigned) (x2-x1), (unsigned) (y2-y1),
                0, 360*64);
      }
      if (rectOvalPtr->fillStipple != None) {
          XSetTSOrigin(display, rectOvalPtr->fillGC, 0, 0);
      }
    }
    if (rectOvalPtr->outlineGC != None) {
      if (rectOvalPtr->header.typePtr == &tkRectangleType) {
          XDrawRectangle(display, drawable, rectOvalPtr->outlineGC,
                x1, y1, (unsigned) (x2-x1), (unsigned) (y2-y1));
      } else {
          XDrawArc(display, drawable, rectOvalPtr->outlineGC,
                x1, y1, (unsigned) (x2-x1), (unsigned) (y2-y1), 0, 360*64);
      }
    }
}

/*
 *--------------------------------------------------------------
 *
 * RectToPoint --
 *
 *    Computes the distance from a given point to a given
 *    rectangle, 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 rectangle.  If the
 *    point isn't inside the rectangle then the return value is the
 *    distance from the point to the rectangle.  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
RectToPoint(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. */
{
    RectOvalItem *rectPtr = (RectOvalItem *) itemPtr;
    double xDiff, yDiff, x1, y1, x2, y2, inc, tmp;

    /*
     * Generate a new larger rectangle that includes the border
     * width, if there is one.
     */

    x1 = rectPtr->bbox[0];
    y1 = rectPtr->bbox[1];
    x2 = rectPtr->bbox[2];
    y2 = rectPtr->bbox[3];
    if (rectPtr->outlineGC != None) {
      inc = rectPtr->width/2.0;
      x1 -= inc;
      y1 -= inc;
      x2 += inc;
      y2 += inc;
    }

    /*
     * If the point is inside the rectangle, handle specially:
     * distance is 0 if rectangle is filled, otherwise compute
     * distance to nearest edge of rectangle and subtract width
     * of edge.
     */

    if ((pointPtr[0] >= x1) && (pointPtr[0] < x2)
            && (pointPtr[1] >= y1) && (pointPtr[1] < y2)) {
      if ((rectPtr->fillGC != None) || (rectPtr->outlineGC == None)) {
          return 0.0;
      }
      xDiff = pointPtr[0] - x1;
      tmp = x2 - pointPtr[0];
      if (tmp < xDiff) {
          xDiff = tmp;
      }
      yDiff = pointPtr[1] - y1;
      tmp = y2 - pointPtr[1];
      if (tmp < yDiff) {
          yDiff = tmp;
      }
      if (yDiff < xDiff) {
          xDiff = yDiff;
      }
      xDiff -= rectPtr->width;
      if (xDiff < 0.0) {
          return 0.0;
      }
      return xDiff;
    }

    /*
     * Point is outside rectangle.
     */

    if (pointPtr[0] < x1) {
      xDiff = x1 - pointPtr[0];
    } else if (pointPtr[0] > x2)  {
      xDiff = pointPtr[0] - x2;
    } else {
      xDiff = 0;
    }

    if (pointPtr[1] < y1) {
      yDiff = y1 - pointPtr[1];
    } else if (pointPtr[1] > y2)  {
      yDiff = pointPtr[1] - y2;
    } else {
      yDiff = 0;
    }

    return hypot(xDiff, yDiff);
}

/*
 *--------------------------------------------------------------
 *
 * OvalToPoint --
 *
 *    Computes the distance from a given point to a given
 *    oval, 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 oval.  If the
 *    point isn't inside the oval then the return value is the
 *    distance from the point to the oval.  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
OvalToPoint(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. */
{
    RectOvalItem *ovalPtr = (RectOvalItem *) itemPtr;
    double width;
    int filled;

    width = ovalPtr->width;
    filled = ovalPtr->fillGC != None;
    if (ovalPtr->outlineGC == None) {
      width = 0.0;
      filled = 1;
    }
    return TkOvalToPoint(ovalPtr->bbox, width, filled, pointPtr);
}

/*
 *--------------------------------------------------------------
 *
 * RectToArea --
 *
 *    This procedure is called to determine whether an item
 *    lies entirely inside, entirely outside, or overlapping
 *    a given rectangle.
 *
 * 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
RectToArea(canvas, itemPtr, areaPtr)
    Tk_Canvas canvas;         /* Canvas containing item. */
    Tk_Item *itemPtr;         /* Item to check against rectangle. */
    double *areaPtr;          /* Pointer to array of four coordinates
                         * (x1, y1, x2, y2) describing rectangular
                         * area.  */
{
    RectOvalItem *rectPtr = (RectOvalItem *) itemPtr;
    double halfWidth;

    halfWidth = rectPtr->width/2.0;
    if (rectPtr->outlineGC == None) {
      halfWidth = 0.0;
    }

    if ((areaPtr[2] <= (rectPtr->bbox[0] - halfWidth))
          || (areaPtr[0] >= (rectPtr->bbox[2] + halfWidth))
          || (areaPtr[3] <= (rectPtr->bbox[1] - halfWidth))
          || (areaPtr[1] >= (rectPtr->bbox[3] + halfWidth))) {
      return -1;
    }
    if ((rectPtr->fillGC == None) && (rectPtr->outlineGC != None)
          && (areaPtr[0] >= (rectPtr->bbox[0] + halfWidth))
          && (areaPtr[1] >= (rectPtr->bbox[1] + halfWidth))
          && (areaPtr[2] <= (rectPtr->bbox[2] - halfWidth))
          && (areaPtr[3] <= (rectPtr->bbox[3] - halfWidth))) {
      return -1;
    }
    if ((areaPtr[0] <= (rectPtr->bbox[0] - halfWidth))
          && (areaPtr[1] <= (rectPtr->bbox[1] - halfWidth))
          && (areaPtr[2] >= (rectPtr->bbox[2] + halfWidth))
          && (areaPtr[3] >= (rectPtr->bbox[3] + halfWidth))) {
      return 1;
    }
    return 0;
}

/*
 *--------------------------------------------------------------
 *
 * OvalToArea --
 *
 *    This procedure is called to determine whether an item
 *    lies entirely inside, entirely outside, or overlapping
 *    a given rectangular 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
OvalToArea(canvas, itemPtr, areaPtr)
    Tk_Canvas canvas;         /* Canvas containing item. */
    Tk_Item *itemPtr;         /* Item to check against oval. */
    double *areaPtr;          /* Pointer to array of four coordinates
                         * (x1, y1, x2, y2) describing rectangular
                         * area.  */
{
    RectOvalItem *ovalPtr = (RectOvalItem *) itemPtr;
    double oval[4], halfWidth;
    int result;

    /*
     * Expand the oval to include the width of the outline, if any.
     */

    halfWidth = ovalPtr->width/2.0;
    if (ovalPtr->outlineGC == None) {
      halfWidth = 0.0;
    }
    oval[0] = ovalPtr->bbox[0] - halfWidth;
    oval[1] = ovalPtr->bbox[1] - halfWidth;
    oval[2] = ovalPtr->bbox[2] + halfWidth;
    oval[3] = ovalPtr->bbox[3] + halfWidth;

    result = TkOvalToArea(oval, areaPtr);

    /*
     * If the rectangle appears to overlap the oval and the oval
     * isn't filled, do one more check to see if perhaps all four
     * of the rectangle's corners are totally inside the oval's
     * unfilled center, in which case we should return "outside".
     */

    if ((result == 0) && (ovalPtr->outlineGC != None)
          && (ovalPtr->fillGC == None)) {
      double centerX, centerY, width, height;
      double xDelta1, yDelta1, xDelta2, yDelta2;

      centerX = (ovalPtr->bbox[0] + ovalPtr->bbox[2])/2.0;
      centerY = (ovalPtr->bbox[1] + ovalPtr->bbox[3])/2.0;
      width = (ovalPtr->bbox[2] - ovalPtr->bbox[0])/2.0 - halfWidth;
      height = (ovalPtr->bbox[3] - ovalPtr->bbox[1])/2.0 - halfWidth;
      xDelta1 = (areaPtr[0] - centerX)/width;
      xDelta1 *= xDelta1;
      yDelta1 = (areaPtr[1] - centerY)/height;
      yDelta1 *= yDelta1;
      xDelta2 = (areaPtr[2] - centerX)/width;
      xDelta2 *= xDelta2;
      yDelta2 = (areaPtr[3] - centerY)/height;
      yDelta2 *= yDelta2;
      if (((xDelta1 + yDelta1) < 1.0)
            && ((xDelta1 + yDelta2) < 1.0)
            && ((xDelta2 + yDelta1) < 1.0)
            && ((xDelta2 + yDelta2) < 1.0)) {
          return -1;
      }
    }
    return result;
}

/*
 *--------------------------------------------------------------
 *
 * ScaleRectOval --
 *
 *    This procedure is invoked to rescale a rectangle or oval
 *    item.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    The rectangle or oval 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
ScaleRectOval(canvas, itemPtr, originX, originY, scaleX, scaleY)
    Tk_Canvas canvas;               /* Canvas containing rectangle. */
    Tk_Item *itemPtr;               /* Rectangle 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. */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;

    rectOvalPtr->bbox[0] = originX + scaleX*(rectOvalPtr->bbox[0] - originX);
    rectOvalPtr->bbox[1] = originY + scaleY*(rectOvalPtr->bbox[1] - originY);
    rectOvalPtr->bbox[2] = originX + scaleX*(rectOvalPtr->bbox[2] - originX);
    rectOvalPtr->bbox[3] = originY + scaleY*(rectOvalPtr->bbox[3] - originY);
    ComputeRectOvalBbox(canvas, rectOvalPtr);
}

/*
 *--------------------------------------------------------------
 *
 * TranslateRectOval --
 *
 *    This procedure is called to move a rectangle or oval by a
 *    given amount.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    The position of the rectangle or oval is offset by
 *    (xDelta, yDelta), and the bounding box is updated in the
 *    generic part of the item structure.
 *
 *--------------------------------------------------------------
 */

static void
TranslateRectOval(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. */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;

    rectOvalPtr->bbox[0] += deltaX;
    rectOvalPtr->bbox[1] += deltaY;
    rectOvalPtr->bbox[2] += deltaX;
    rectOvalPtr->bbox[3] += deltaY;
    ComputeRectOvalBbox(canvas, rectOvalPtr);
}

/*
 *--------------------------------------------------------------
 *
 * RectOvalToPostscript --
 *
 *    This procedure is called to generate Postscript for
 *    rectangle and oval 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 rectangle is
 *    appended to the result.
 *
 * Side effects:
 *    None.
 *
 *--------------------------------------------------------------
 */

static int
RectOvalToPostscript(interp, canvas, itemPtr, prepass)
    Tcl_Interp *interp;             /* Interpreter for error reporting. */
    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. */
{
    char pathCmd[500], string[100];
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;
    double y1, y2;

    y1 = Tk_CanvasPsY(canvas, rectOvalPtr->bbox[1]);
    y2 = Tk_CanvasPsY(canvas, rectOvalPtr->bbox[3]);

    /*
     * Generate a string that creates a path for the rectangle or oval.
     * This is the only part of the procedure's code that is type-
     * specific.
     */


    if (rectOvalPtr->header.typePtr == &tkRectangleType) {
      sprintf(pathCmd, "%.15g %.15g moveto %.15g 0 rlineto 0 %.15g rlineto %.15g 0 rlineto closepath\n",
            rectOvalPtr->bbox[0], y1,
            rectOvalPtr->bbox[2]-rectOvalPtr->bbox[0], y2-y1,
            rectOvalPtr->bbox[0]-rectOvalPtr->bbox[2]);
    } else {
      sprintf(pathCmd, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale 1 0 moveto 0 0 1 0 360 arc\nsetmatrix\n",
            (rectOvalPtr->bbox[0] + rectOvalPtr->bbox[2])/2, (y1 + y2)/2,
            (rectOvalPtr->bbox[2] - rectOvalPtr->bbox[0])/2, (y1 - y2)/2);
    }

    /*
     * First draw the filled area of the rectangle.
     */

    if (rectOvalPtr->fillColor != NULL) {
      Tcl_AppendResult(interp, pathCmd, (char *) NULL);
      if (Tk_CanvasPsColor(interp, canvas, rectOvalPtr->fillColor)
            != TCL_OK) {
          return TCL_ERROR;
      }
      if (rectOvalPtr->fillStipple != None) {
          Tcl_AppendResult(interp, "clip ", (char *) NULL);
          if (Tk_CanvasPsStipple(interp, canvas, rectOvalPtr->fillStipple)
                != TCL_OK) {
            return TCL_ERROR;
          }
          if (rectOvalPtr->outlineColor != NULL) {
            Tcl_AppendResult(interp, "grestore gsave\n", (char *) NULL);
          }
      } else {
          Tcl_AppendResult(interp, "fill\n", (char *) NULL);
      }
    }

    /*
     * Now draw the outline, if there is one.
     */

    if (rectOvalPtr->outlineColor != NULL) {
      Tcl_AppendResult(interp, pathCmd, (char *) NULL);
      sprintf(string, "%d setlinewidth", rectOvalPtr->width);
      Tcl_AppendResult(interp, string,
            " 0 setlinejoin 2 setlinecap\n", (char *) NULL);
      if (Tk_CanvasPsColor(interp, canvas, rectOvalPtr->outlineColor)
            != TCL_OK) {
          return TCL_ERROR;
      }
      Tcl_AppendResult(interp, "stroke\n", (char *) NULL);
    }
    return TCL_OK;
}

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