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-rw-r--r--macosx/tkMacOSXDraw.c43
1 files changed, 40 insertions, 3 deletions
diff --git a/macosx/tkMacOSXDraw.c b/macosx/tkMacOSXDraw.c
index 40400c2..6631b4f 100644
--- a/macosx/tkMacOSXDraw.c
+++ b/macosx/tkMacOSXDraw.c
@@ -1460,12 +1460,12 @@ XMaxRequestSize(
* a damage region.
*
* Results:
- * Returns 0 if the scroll generated no additional damage.
+ * Returns 0 if the scroll genereated no additional damage.
* Otherwise, sets the region that needs to be repainted after
* scrolling and returns 1.
*
* Side effects:
- * Scrolls the rectangle in the window.
+ * Scrolls the bits in the window.
*
*----------------------------------------------------------------------
*/
@@ -1518,9 +1518,46 @@ TkScrollWindow(
/* Scroll the rectangle. */
[view scrollRect:NSRectFromCGRect(scroll_src) by:NSMakeSize(dx, -dy)];
[view displayRect:NSRectFromCGRect(scroll_dst)];
+
+ /*
+ * When a Text widget contains embedded images, scrolling generates
+ * lots of artifacts involving multiple copies of the images
+ * displayed on top of each other. Extensive experimentation, with
+ * very little help from the Apple documentation, indicates that
+ * whenever an image is displayed it gets added as a subview, which
+ * then gets automatically redisplayed in its original location.
+ *
+ * We do two things to combat this. First, each subview that meets
+ * the scroll area is added as a damage rectangle. Second, we
+ * redisplay the subviews after the scroll.
+ */
+
+ /*
+ * Step 1: Find any subviews that meet the scroll area and mark
+ * them as damaged. Use Tk coordinates, shifted to account for the
+ * future scrolling.
+ */
+
+ for (NSView *subview in [view subviews] ) {
+ NSRect frame = [subview frame];
+ CGRect subviewRect = CGRectMake(
+ frame.origin.x - macDraw->xOff + dx,
+ (bounds.size.height - frame.origin.y - frame.size.height) - macDraw->yOff + dy,
+ frame.size.width, frame.size.height);
+ /* Rectangles with negative coordinates seem to cause trouble. */
+ if (subviewRect.origin.y < 0 && subviewRect.origin.y + subviewRect.size.height > 0) {
+ subviewRect.origin.y = 0;
+ }
+ CGRect intersection = CGRectIntersection(srcRect, subviewRect);
+ if (! CGRectIsEmpty(intersection) ){
+ dstRgn = HIShapeCreateWithRect(&subviewRect);
+ ChkErr(HIShapeUnion, dmgRgn, dstRgn, (HIMutableShapeRef) dmgRgn);
+ CFRelease(dstRgn);
+ }
+ }
+
}
}
-
if ( dmgRgn == NULL ) {