mTk/generic/tkCanvImg.c

/*
 * tkCanvImg.c --
 *
 *      This file implements image items for canvas widgets.
 *
 * Copyright (c) 1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 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: tkCanvImg.c,v 1.6 2003/02/09 07:48:22 hobbs Exp $
 */

#include "tkInt.h"
#include "tkPort.h"
#include "tkCanvases.h"

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

typedef struct ImageItem  {
    Tk_Item header;             /* Generic stuff that's the same for all
				 * types.  MUST BE FIRST IN STRUCTURE. */
    Tk_Canvas canvas;           /* Canvas containing the image. */
    double x, y;                /* Coordinates of positioning point for
				 * image. */
    Tk_Anchor anchor;           /* Where to anchor image relative to
				 * (x,y). */
    char *imageString;          /* String describing -image option (malloc-ed).
				 * NULL means no image right now. */
    char *activeImageString;    /* String describing -activeimage option.
				 * NULL means no image right now. */
    char *disabledImageString;  /* String describing -disabledimage option.
				 * NULL means no image right now. */
    Tk_Image image;             /* Image to display in window, or NULL if
				 * no image at present. */
    Tk_Image activeImage;       /* Image to display in window, or NULL if
				 * no image at present. */
    Tk_Image disabledImage;     /* Image to display in window, or NULL if
				 * no image at present. */
} ImageItem;

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

static Tk_CustomOption stateOption = {
    TkStateParseProc,
    TkStatePrintProc, (ClientData) 2
};
static Tk_CustomOption tagsOption = {
    Tk_CanvasTagsParseProc,
    Tk_CanvasTagsPrintProc, (ClientData) NULL
};

static Tk_ConfigSpec configSpecs[] = {
    {TK_CONFIG_STRING, "-activeimage", (char *) NULL, (char *) NULL,
	(char *) NULL, Tk_Offset(ImageItem, activeImageString),
	TK_CONFIG_NULL_OK},
    {TK_CONFIG_ANCHOR, "-anchor", (char *) NULL, (char *) NULL,
	"center", Tk_Offset(ImageItem, anchor), TK_CONFIG_DONT_SET_DEFAULT},
    {TK_CONFIG_OBJECT, "-disabledimage", (char *) NULL, (char *) NULL,
	(char *) NULL, Tk_Offset(ImageItem, disabledImageString),
	TK_CONFIG_NULL_OK},
    {TK_CONFIG_OBJECT, "-image", (char *) NULL, (char *) NULL,
	(char *) NULL, Tk_Offset(ImageItem, imageString), TK_CONFIG_NULL_OK},
    {TK_CONFIG_CUSTOM, "-state", (char *) NULL, (char *) NULL,
	(char *) NULL, Tk_Offset(Tk_Item, state), TK_CONFIG_NULL_OK,
	&stateOption},
    {TK_CONFIG_CUSTOM, "-tags", (char *) NULL, (char *) NULL,
	(char *) NULL, 0, TK_CONFIG_NULL_OK, &tagsOption},
    {TK_CONFIG_CALLBACK, "-updatecommand", (char *) NULL, (char *) NULL,
	(char *) NULL, Tk_Offset(Tk_Item, updateCmd), TK_CONFIG_NULL_OK},
    {TK_CONFIG_END, (char *) NULL, (char *) NULL, (char *) NULL,
	(char *) NULL, 0, 0}
};

/*
 * Prototypes for procedures defined in this file:
 */

static void             ImageChangedProc _ANSI_ARGS_((ClientData clientData,
			    int x, int y, int width, int height, int imgWidth,
			    int imgHeight));
static int              ImageCoords _ANSI_ARGS_((Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr, int argc,
			    Tcl_Obj *CONST objv[]));
static int              ImageToArea _ANSI_ARGS_((Tk_Canvas canvas,
			    Tk_Item *itemPtr, double *rectPtr));
static double           ImageToPoint _ANSI_ARGS_((Tk_Canvas canvas,
			    Tk_Item *itemPtr, double *coordPtr));
static int              ImageToPostscript _ANSI_ARGS_((Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr, int prepass));
static void             ComputeImageBbox _ANSI_ARGS_((Tk_Canvas canvas,
			    ImageItem *imgPtr));
static int              ConfigureImage _ANSI_ARGS_((Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr, int argc,
			    Tcl_Obj *CONST objv[], int flags));
static int              CreateImage _ANSI_ARGS_((Tcl_Interp *interp,
			    Tk_Canvas canvas, struct Tk_Item *itemPtr,
			    int argc, Tcl_Obj *CONST objv[]));
static void             DeleteImage _ANSI_ARGS_((Tk_Canvas canvas,
			    Tk_Item *itemPtr, Display *display));
static void             DisplayImage _ANSI_ARGS_((Tk_Canvas canvas,
			    Tk_Item *itemPtr, Display *display, Drawable dst,
			    int x, int y, int width, int height));
static void             ScaleImage _ANSI_ARGS_((Tk_Canvas canvas,
			    Tk_Item *itemPtr, double originX, double originY,
			    double scaleX, double scaleY));
static void             TranslateImage _ANSI_ARGS_((Tk_Canvas canvas,
			    Tk_Item *itemPtr, double deltaX, double deltaY));

/*
 * The structures below defines the image item type in terms of
 * procedures that can be invoked by generic item code.
 */

Tk_ItemType tkImageType = {
    "image",                            /* name */
    sizeof(ImageItem),                  /* itemSize */
    CreateImage,                        /* createProc */
    configSpecs,                        /* configSpecs */
    ConfigureImage,                     /* configureProc */
    ImageCoords,                        /* coordProc */
    DeleteImage,                        /* deleteProc */
    DisplayImage,                       /* displayProc */
    TK_CONFIG_OBJS,                     /* flags */
    ImageToPoint,                       /* pointProc */
    ImageToArea,                        /* areaProc */
    ImageToPostscript,                  /* postscriptProc */
    ScaleImage,                         /* scaleProc */
    TranslateImage,                     /* 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 */
};

/*
 *--------------------------------------------------------------
 *
 * CreateImage --
 *
 *      This procedure is invoked to create a new image
 *      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
 *      the interp's result;  in this case itemPtr is left uninitialized,
 *      so it can be safely freed by the caller.
 *
 * Side effects:
 *      A new image item is created.
 *
 *--------------------------------------------------------------
 */

static int
CreateImage(interp, canvas, itemPtr, objc, objv)
    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 objc;                           /* Number of arguments in objv. */
    Tcl_Obj *CONST objv[];              /* Arguments describing rectangle. */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;
    int i;

    if (objc == 0) {
	panic("canvas did not pass any coords\n");
    }

    /*
     * Initialize item's record.
     */

    imgPtr->canvas = canvas;
    imgPtr->anchor = TK_ANCHOR_CENTER;
    imgPtr->imageString = NULL;
    imgPtr->activeImageString = NULL;
    imgPtr->disabledImageString = NULL;
    imgPtr->image = NULL;
    imgPtr->activeImage = NULL;
    imgPtr->disabledImage = NULL;

    /*
     * Process the arguments to fill in the item record.
     * Only 1 (list) or 2 (x y) coords are allowed.
     */

    if (objc == 1) {
	i = 1;
    } else {
	char *arg = Tcl_GetString(objv[1]);
	i = 2;
	if ((arg[0] == '-') && (arg[1] >= 'a') && (arg[1] <= 'z')) {
	    i = 1;
	}
    }
    if ((ImageCoords(interp, canvas, itemPtr, i, objv) != TCL_OK)) {
	goto error;
    }
    if (ConfigureImage(interp, canvas, itemPtr, objc-i, objv+i, 0) == TCL_OK) {
	return TCL_OK;
    }

    error:
    DeleteImage(canvas, itemPtr, Tk_Display(Tk_CanvasTkwin(canvas)));
    return TCL_ERROR;
}

/*
 *--------------------------------------------------------------
 *
 * ImageCoords --
 *
 *      This procedure is invoked to process the "coords" widget
 *      command on image items.  See the user documentation for
 *      details on what it does.
 *
 * Results:
 *      Returns TCL_OK or TCL_ERROR, and sets the interp's result.
 *
 * Side effects:
 *      The coordinates for the given item may be changed.
 *
 *--------------------------------------------------------------
 */

static int
ImageCoords(interp, canvas, itemPtr, objc, objv)
    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 objc;                           /* Number of coordinates supplied in
					 * objv. */
    Tcl_Obj *CONST objv[];              /* Array of coordinates: x1, y1,
					 * x2, y2, ... */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;

    if (objc == 0) {
	Tcl_Obj *obj = Tcl_NewObj();
	Tcl_Obj *subobj = Tcl_NewDoubleObj(imgPtr->x);
	Tcl_ListObjAppendElement(interp, obj, subobj);
	subobj = Tcl_NewDoubleObj(imgPtr->y);
	Tcl_ListObjAppendElement(interp, obj, subobj);
	Tcl_SetObjResult(interp, obj);
    } else if (objc < 3) {
	if (objc==1) {
	    if (Tcl_ListObjGetElements(interp, objv[0], &objc,
		    (Tcl_Obj ***) &objv) != TCL_OK) {
		return TCL_ERROR;
	    } else if (objc != 2) {
		char buf[64];

		sprintf(buf, "wrong # coordinates: expected 2, got %d", objc);
		Tcl_SetResult(interp, buf, TCL_VOLATILE);
		return TCL_ERROR;
	    }
	}
	if ((Tk_CanvasGetCoordFromObj(interp, canvas, objv[0], &imgPtr->x) != TCL_OK)
		|| (Tk_CanvasGetCoordFromObj(interp, canvas, objv[1],
		    &imgPtr->y) != TCL_OK)) {
	    return TCL_ERROR;
	}
	ComputeImageBbox(canvas, imgPtr);
    } else {
	char buf[64];

	sprintf(buf, "wrong # coordinates: expected 0 or 2, got %d", objc);
	Tcl_SetResult(interp, buf, TCL_VOLATILE);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ConfigureImage --
 *
 *      This procedure is invoked to configure various aspects
 *      of an image item, such as its anchor position.
 *
 * Results:
 *      A standard Tcl result code.  If an error occurs, then
 *      an error message is left in the interp's result.
 *
 * Side effects:
 *      Configuration information may be set for itemPtr.
 *
 *--------------------------------------------------------------
 */

static int
ConfigureImage(interp, canvas, itemPtr, objc, objv, flags)
    Tcl_Interp *interp;         /* Used for error reporting. */
    Tk_Canvas canvas;           /* Canvas containing itemPtr. */
    Tk_Item *itemPtr;           /* Image item to reconfigure. */
    int objc;                   /* Number of elements in objv.  */
    Tcl_Obj *CONST objv[];      /* Arguments describing things to configure. */
    int flags;                  /* Flags to pass to Tk_ConfigureWidget. */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;
    Tk_Window tkwin;
    Tk_Image image;

    tkwin = Tk_CanvasTkwin(canvas);
    if (TCL_OK != Tk_ConfigureWidget(interp, tkwin, configSpecs, objc,
	    objv, (char *) imgPtr, flags|TK_CONFIG_OBJS)) {
	return TCL_ERROR;
    }

    /*
     * Create the image.  Save the old image around and don't free it
     * until after the new one is allocated.  This keeps the reference
     * count from going to zero so the image doesn't have to be recreated
     * if it hasn't changed.
     */

    if (imgPtr->activeImageString != NULL) {
	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
    } else {
	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
    }
    if (imgPtr->imageString != NULL) {
	image = Tk_GetImage(interp, tkwin, imgPtr->imageString,
		ImageChangedProc, (ClientData) imgPtr);
	if (image == NULL) {
	    return TCL_ERROR;
	}
    } else {
	image = NULL;
    }
    if (imgPtr->image != NULL) {
	Tk_FreeImage(imgPtr->image);
    }
    imgPtr->image = image;
    if (imgPtr->activeImageString != NULL) {
	image = Tk_GetImage(interp, tkwin, imgPtr->activeImageString,
		ImageChangedProc, (ClientData) imgPtr);
	if (image == NULL) {
	    return TCL_ERROR;
	}
    } else {
	image = NULL;
    }
    if (imgPtr->activeImage != NULL) {
	Tk_FreeImage(imgPtr->activeImage);
    }
    imgPtr->activeImage = image;
    if (imgPtr->disabledImageString != NULL) {
	image = Tk_GetImage(interp, tkwin, imgPtr->disabledImageString,
		ImageChangedProc, (ClientData) imgPtr);
	if (image == NULL) {
	    return TCL_ERROR;
	}
    } else {
	image = NULL;
    }
    if (imgPtr->disabledImage != NULL) {
	Tk_FreeImage(imgPtr->disabledImage);
    }
    imgPtr->disabledImage = image;
    ComputeImageBbox(canvas, imgPtr);
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * DeleteImage --
 *
 *      This procedure is called to clean up the data structure
 *      associated with a image item.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Resources associated with itemPtr are released.
 *
 *--------------------------------------------------------------
 */

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

    if (imgPtr->imageString != NULL) {
	ckfree(imgPtr->imageString);
    }
    if (imgPtr->activeImageString != NULL) {
	ckfree(imgPtr->activeImageString);
    }
    if (imgPtr->disabledImageString != NULL) {
	ckfree(imgPtr->disabledImageString);
    }
    if (imgPtr->image != NULL) {
	Tk_FreeImage(imgPtr->image);
    }
    if (imgPtr->activeImage != NULL) {
	Tk_FreeImage(imgPtr->activeImage);
    }
    if (imgPtr->disabledImage != NULL) {
	Tk_FreeImage(imgPtr->disabledImage);
    }
}

/*
 *--------------------------------------------------------------
 *
 * ComputeImageBbox --
 *
 *      This procedure is invoked to compute the bounding box of
 *      all the pixels that may be drawn as part of a image item.
 *      This procedure is where the child image's placement is
 *      computed.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The fields x1, y1, x2, and y2 are updated in the header
 *      for itemPtr.
 *
 *--------------------------------------------------------------
 */

	/* ARGSUSED */
static void
ComputeImageBbox(canvas, imgPtr)
    Tk_Canvas canvas;                   /* Canvas that contains item. */
    ImageItem *imgPtr;                  /* Item whose bbox is to be
					 * recomputed. */
{
    int width, height;
    int x, y;
    Tk_Image image;
    Tk_State state = Tk_GetItemState(canvas, &imgPtr->header);

    image = imgPtr->image;
    if (((TkCanvas *)canvas)->currentItemPtr == (Tk_Item *)imgPtr) {
	if (imgPtr->activeImage != NULL) {
	    image = imgPtr->activeImage;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (imgPtr->disabledImage != NULL) {
	    image = imgPtr->disabledImage;
	}
    }

    x = (int) (imgPtr->x + ((imgPtr->x >= 0) ? 0.5 : - 0.5));
    y = (int) (imgPtr->y + ((imgPtr->y >= 0) ? 0.5 : - 0.5));

    if ((state == TK_STATE_HIDDEN) || (image == None)) {
	imgPtr->header.x1 = imgPtr->header.x2 = x;
	imgPtr->header.y1 = imgPtr->header.y2 = y;
	return;
    }

    /*
     * Compute location and size of image, using anchor information.
     */

    Tk_SizeOfImage(image, &width, &height);
    switch (imgPtr->anchor) {
	case TK_ANCHOR_N:
	    x -= width/2;
	    break;
	case TK_ANCHOR_NE:
	    x -= width;
	    break;
	case TK_ANCHOR_E:
	    x -= width;
	    y -= height/2;
	    break;
	case TK_ANCHOR_SE:
	    x -= width;
	    y -= height;
	    break;
	case TK_ANCHOR_S:
	    x -= width/2;
	    y -= height;
	    break;
	case TK_ANCHOR_SW:
	    y -= height;
	    break;
	case TK_ANCHOR_W:
	    y -= height/2;
	    break;
	case TK_ANCHOR_NW:
	    break;
	case TK_ANCHOR_CENTER:
	    x -= width/2;
	    y -= height/2;
	    break;
    }

    /*
     * Store the information in the item header.
     */

    imgPtr->header.x1 = x;
    imgPtr->header.y1 = y;
    imgPtr->header.x2 = x + width;
    imgPtr->header.y2 = y + height;
}

/*
 *--------------------------------------------------------------
 *
 * DisplayImage --
 *
 *      This procedure is invoked to draw a image item in a given
 *      drawable.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      ItemPtr is drawn in drawable using the transformation
 *      information in canvas.
 *
 *--------------------------------------------------------------
 */

static void
DisplayImage(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). */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;
    short drawableX, drawableY;
    Tk_Image image;
    Tk_State state = Tk_GetItemState(canvas, itemPtr);

    image = imgPtr->image;
    if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
	if (imgPtr->activeImage != NULL) {
	    image = imgPtr->activeImage;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (imgPtr->disabledImage != NULL) {
	    image = imgPtr->disabledImage;
	}
    }

    if (image == NULL) {
	return;
    }

    /*
     * Translate the coordinates to those of the image, then redisplay it.
     */

    Tk_CanvasDrawableCoords(canvas, (double) x, (double) y,
	    &drawableX, &drawableY);
    Tk_RedrawImage(image, x - imgPtr->header.x1, y - imgPtr->header.y1,
	    width, height, drawable, drawableX, drawableY);
}

/*
 *--------------------------------------------------------------
 *
 * ImageToPoint --
 *
 *      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 image.  If the
 *      point isn't inside the image then the return value is the
 *      distance from the point to the image.
 *
 * Side effects:
 *      None.
 *
 *--------------------------------------------------------------
 */

static double
ImageToPoint(canvas, itemPtr, coordPtr)
    Tk_Canvas canvas;           /* Canvas containing item. */
    Tk_Item *itemPtr;           /* Item to check against point. */
    double *coordPtr;           /* Pointer to x and y coordinates. */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;
    double x1, x2, y1, y2, xDiff, yDiff;

    x1 = imgPtr->header.x1;
    y1 = imgPtr->header.y1;
    x2 = imgPtr->header.x2;
    y2 = imgPtr->header.y2;

    /*
     * Point is outside rectangle.
     */

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

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

    return hypot(xDiff, yDiff);
}

/*
 *--------------------------------------------------------------
 *
 * ImageToArea --
 *
 *      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.
 *
 *--------------------------------------------------------------
 */

static int
ImageToArea(canvas, itemPtr, rectPtr)
    Tk_Canvas canvas;           /* Canvas containing item. */
    Tk_Item *itemPtr;           /* Item to check against rectangle. */
    double *rectPtr;            /* Pointer to array of four coordinates
				 * (x1, y1, x2, y2) describing rectangular
				 * area.  */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;

    if ((rectPtr[2] <= imgPtr->header.x1)
	    || (rectPtr[0] >= imgPtr->header.x2)
	    || (rectPtr[3] <= imgPtr->header.y1)
	    || (rectPtr[1] >= imgPtr->header.y2)) {
	return -1;
    }
    if ((rectPtr[0] <= imgPtr->header.x1)
	    && (rectPtr[1] <= imgPtr->header.y1)
	    && (rectPtr[2] >= imgPtr->header.x2)
	    && (rectPtr[3] >= imgPtr->header.y2)) {
	return 1;
    }
    return 0;
}

/*
 *--------------------------------------------------------------
 *
 * ImageToPostscript --
 *
 *      This procedure is called to generate Postscript for
 *      image 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
ImageToPostscript(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.*/
{
    ImageItem *imgPtr = (ImageItem *)itemPtr;
    Tk_Window canvasWin = Tk_CanvasTkwin(canvas);

    char buffer[256];
    double x, y;
    int width, height;
    Tk_Image image;
    Tk_State state = Tk_GetItemState(canvas, itemPtr);

    image = imgPtr->image;
    if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
	if (imgPtr->activeImage != NULL) {
	    image = imgPtr->activeImage;
	}
    } else if (state == TK_STATE_DISABLED) {
	if (imgPtr->disabledImage != NULL) {
	    image = imgPtr->disabledImage;
	}
    }
    Tk_SizeOfImage(image, &width, &height);

    /*
     * Compute the coordinates of the lower-left corner of the image,
     * taking into account the anchor position for the image.
     */

    x = imgPtr->x;
    y = Tk_CanvasPsY(canvas, imgPtr->y);

    switch (imgPtr->anchor) {
	case TK_ANCHOR_NW:                      y -= height;            break;
	case TK_ANCHOR_N:       x -= width/2.0; y -= height;            break;
	case TK_ANCHOR_NE:      x -= width;     y -= height;            break;
	case TK_ANCHOR_E:       x -= width;     y -= height/2.0;        break;
	case TK_ANCHOR_SE:      x -= width;                             break;
	case TK_ANCHOR_S:       x -= width/2.0;                         break;
	case TK_ANCHOR_SW:                                              break;
	case TK_ANCHOR_W:                       y -= height/2.0;        break;
	case TK_ANCHOR_CENTER:  x -= width/2.0; y -= height/2.0;        break;
    }

    if (image == NULL) {
	return TCL_OK;
    }

    if (!prepass) {
	sprintf(buffer, "%.15g %.15g", x, y);
	Tcl_AppendResult(interp, buffer, " translate\n", (char *) NULL);
    }

    return Tk_PostscriptImage(image, interp, canvasWin,
	    ((TkCanvas *) canvas)->psInfo, 0, 0, width, height, prepass);
}

/*
 *--------------------------------------------------------------
 *
 * ScaleImage --
 *
 *      This procedure is invoked to rescale an item.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The item 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
ScaleImage(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. */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;

    imgPtr->x = originX + scaleX*(imgPtr->x - originX);
    imgPtr->y = originY + scaleY*(imgPtr->y - originY);
    ComputeImageBbox(canvas, imgPtr);
}

/*
 *--------------------------------------------------------------
 *
 * TranslateImage --
 *
 *      This procedure is called to move an item by a given amount.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The position of the item is offset by (xDelta, yDelta), and
 *      the bounding box is updated in the generic part of the item
 *      structure.
 *
 *--------------------------------------------------------------
 */

static void
TranslateImage(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. */
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;

    imgPtr->x += deltaX;
    imgPtr->y += deltaY;
    ComputeImageBbox(canvas, imgPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * ImageChangedProc --
 *
 *      This procedure is invoked by the image code whenever the manager
 *      for an image does something that affects the image's size or
 *      how it is displayed.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Arranges for the canvas to get redisplayed.
 *
 *----------------------------------------------------------------------
 */

static void
ImageChangedProc(clientData, x, y, width, height, imgWidth, imgHeight)
    ClientData clientData;              /* Pointer to canvas item for image. */
    int x, y;                           /* Upper left pixel (within image)
					 * that must be redisplayed. */
    int width, height;                  /* Dimensions of area to redisplay
					 * (may be <= 0). */
    int imgWidth, imgHeight;            /* New dimensions of image. */
{
    ImageItem *imgPtr = (ImageItem *) clientData;

    /*
     * If the image's size changed and it's not anchored at its
     * northwest corner then just redisplay the entire area of the
     * image.  This is a bit over-conservative, but we need to do
     * something because a size change also means a position change.
     */

    if (((imgPtr->header.x2 - imgPtr->header.x1) != imgWidth)
	    || ((imgPtr->header.y2 - imgPtr->header.y1) != imgHeight)) {
	x = y = 0;
	width = imgWidth;
	height = imgHeight;
	Tk_CanvasEventuallyRedraw(imgPtr->canvas, imgPtr->header.x1,
		imgPtr->header.y1, imgPtr->header.x2, imgPtr->header.y2);
    }
    ComputeImageBbox(imgPtr->canvas, imgPtr);
    Tk_CanvasEventuallyRedraw(imgPtr->canvas, imgPtr->header.x1 + x,
	    imgPtr->header.y1 + y, (int) (imgPtr->header.x1 + x + width),
	    (int) (imgPtr->header.y1 + y + height));
}