tkcanvimg.c

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 *	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;

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

    if (imgPtr->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(imgPtr->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;

    if (imgPtr->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(imgPtr->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;
}

/*
 *--------------------------------------------------------------
 *
 * 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));
}