Fixed transparency issues and crashes related to PhotoImages and greatly simplified

the PhotoImage display procedure.

1 files changed, 37 insertions, 41 deletions

diff --git a/macosx/tkMacOSXImage.c b/macosx/tkMacOSXImage.c
index 861b7ab..2b747f1 100644
--- a/macosx/tkMacOSXImage.c
+++ b/macosx/tkMacOSXImage.c
@@ -6,7 +6,7 @@
  * Copyright (c) 1995-1997 Sun Microsystems, Inc.
  * Copyright 2001-2009, Apple Inc.
  * Copyright (c) 2005-2009 Daniel A. Steffen <das@users.sourceforge.net>
- * Copyright 2017 Marc Culler.
+ * Copyright 2017-2018 Marc Culler.
  *
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
@@ -29,7 +29,8 @@ _XInitImageFuncPtrs(
  *
  * TkMacOSXCreateCGImageWithXImage --
  *
- *	Create CGImage from XImage, copying the image data.
+ *	Create CGImage from XImage, copying the image data.  Called
+ *      in Tk_PutImage and (currently) nowhere else.
  *
  * Results:
  *	CGImage, release after use.
@@ -46,8 +47,7 @@ static void ReleaseData(void *info, const void *data, size_t size) {
 
 CGImageRef
 TkMacOSXCreateCGImageWithXImage(
-    XImage *image,
-    int use_ximage_alpha)
+    XImage *image)
 {
     CGImageRef img = NULL;
     size_t bitsPerComponent, bitsPerPixel;
@@ -88,21 +88,17 @@ TkMacOSXCreateCGImageWithXImage(
 				    bitsPerPixel, image->bytes_per_line, provider, decode, 0);
 	}
     } else if (image->format == ZPixmap && image->bits_per_pixel == 32) {
+
 	/*
 	 * Color image
 	 */
 
 	CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
-
 	bitsPerComponent = 8;
 	bitsPerPixel = 32;
 	bitmapInfo = (image->byte_order == MSBFirst ?
-		      kCGBitmapByteOrder32Big : kCGBitmapByteOrder32Little);
-	if (use_ximage_alpha) {
-	    bitmapInfo |= kCGImageAlphaPremultipliedFirst;
-	} else {
-	    bitmapInfo |= kCGImageAlphaNoneSkipFirst;
-	}
+		      kCGBitmapByteOrder32Little : kCGBitmapByteOrder32Big);
+	bitmapInfo |= kCGImageAlphaLast;
 	data = memcpy(ckalloc(len), image->data + image->xoffset, len);
 	if (data) {
 	    provider = CGDataProviderCreateWithData(data, data, len, releaseData);
@@ -128,7 +124,12 @@ TkMacOSXCreateCGImageWithXImage(
  *
  * XGetImage --
  *
- *	This function copies data from a pixmap or window into an XImage.
+ *	This function copies data from a pixmap or window into an XImage.  It
+ *      is essentially never used. At one time it was called by
+ *      pTkImgPhotoDisplay, but that is no longer the case. Currently it is
+ *      called two places, one of which is requesting an XY image which we do
+ *      not support.  It probably does not work correctly -- see the comments
+ *      for TkMacOSXBitmapRepFromDrawableRect.
  *
  * Results:
  *	Returns a newly allocated XImage containing the data from the given
@@ -165,7 +166,6 @@ XGetImage(
     unsigned int bytes_per_row, size, row, n, m;
     unsigned int scalefactor=1, scaled_height=height, scaled_width=width;
     NSWindow *win = TkMacOSXDrawableWindow(drawable);
-    MacDrawable *macDraw = ((MacDrawable*)drawable);
     static enum {unknown, no, yes} has_retina = unknown;
 
     if (win && has_retina == unknown) {
@@ -178,9 +178,11 @@ XGetImage(
     }
 
     if (has_retina == yes) {
+
 	/*
 	 * We only allow scale factors 1 or 2, as Apple currently does.
 	 */
+
 #ifdef __clang__
 	scalefactor = [win backingScaleFactor] == 2.0 ? 2 : 1;
 #endif
@@ -192,8 +194,9 @@ XGetImage(
 	if (width == 0 || height == 0) {
 	    return NULL;
 	}
+
 	bitmap_rep = TkMacOSXBitmapRepFromDrawableRect(drawable,
-		         x, y, width, height);
+			  x, y, width, height);
 	if (!bitmap_rep) {
 	    TkMacOSXDbgMsg("XGetImage: Failed to construct NSBitmapRep");
 	    return NULL;
@@ -212,29 +215,14 @@ XGetImage(
 	    CFRelease(bitmap_rep);
 	    return NULL;
 	}
-
-	if (macDraw->flags & TK_USE_XIMAGE_ALPHA) {
-	    /*
-	     * When called by TkImgPhotoDisplay we are being asked to return a
-	     * background image to be blended with the photoimage using its
-	     * alpha channel, if it has one.  Returning a black pixmap here
-	     * makes TkImgPhotoDisplay create an XImage with a premultiplied
-	     * alpha channel, as favored by Apple.  When TkImgPhotoDisplay
-	     * passes this XImage to TkPutImage, targeting a pixmap, it creates
-	     * an image with correct transparency.  This is used, for example,
-	     * when creating an iconphoto or a menu image from a PNG
-	     * photoimage.
-	     */
-	    bzero(bitmap, size);
-	} else {
-	    memcpy(bitmap, (char *)[bitmap_rep bitmapData], size);
-	}
+	memcpy(bitmap, (char *)[bitmap_rep bitmapData], size);
 	CFRelease(bitmap_rep);
 
 	/*
 	 * When Apple extracts a bitmap from an NSView, it may be in
 	 * either BGRA or ABGR format.  For an XImage we need RGBA.
 	 */
+
 	struct pixel_fmt pixel = bitmap_fmt == 0 ? bgra : abgr;
 
 	for (row = 0, n = 0; row < scaled_height; row++, n += bytes_per_row) {
@@ -514,8 +502,9 @@ XCreateImage(
  *
  * TkPutImage --
  *
- *	Copies a subimage from an in-memory image to a rectangle of
- *	of the specified drawable.
+ *	Copies a rectangular subimage of an XImage into a drawable.
+ *      Currently this is only called by TkImgPhotoDisplay, using
+ *      a Window as the drawable.
  *
  * Results:
  *	None.
@@ -542,23 +531,30 @@ TkPutImage(
     unsigned int height)	/* distination and source. */
 {
     TkMacOSXDrawingContext dc;
-    MacDrawable *macDraw = ((MacDrawable*)drawable);
 
     display->request++;
     if (!TkMacOSXSetupDrawingContext(drawable, gc, 1, &dc)) {
 	return BadDrawable;
     }
     if (dc.context) {
-	CGImageRef img = TkMacOSXCreateCGImageWithXImage(image,
-			     macDraw->flags & TK_USE_XIMAGE_ALPHA);
+	CGRect bounds, srcRect, dstRect;
+	CGImageRef img = TkMacOSXCreateCGImageWithXImage(image);
+	CGContextSetBlendMode(dc.context, kCGBlendModeSourceAtop);
 	if (img) {
-	    /* If the XImage has big pixels, rescale the source dimensions.*/
+
+	    /* If the XImage has big pixels, the source is rescaled to reflect
+	     * the actual pixel dimensions.  This is not currently used, but
+	     * could arise if the image were copied from a retina monitor and
+	     * redrawn on an ordinary monitor.
+	     */
+
 	    int pp = image->pixelpower;
+	    bounds = CGRectMake(0, 0, image->width, image->height);
+	    srcRect = CGRectMake(src_x<<pp, src_y<<pp, width<<pp, height<<pp);
+	    dstRect = CGRectMake(dest_x, dest_y, width, height);
 	    TkMacOSXDrawCGImage(drawable, gc, dc.context,
-		    img, gc->foreground, gc->background,
-		    CGRectMake(0, 0, image->width<<pp, image->height<<pp),
-		    CGRectMake(src_x<<pp, src_y<<pp, width<<pp, height<<pp),
-		    CGRectMake(dest_x, dest_y, width, height));
+				img, gc->foreground, gc->background,
+				bounds, srcRect, dstRect);
 	    CFRelease(img);
 	} else {
 	    TkMacOSXDbgMsg("Invalid source drawable");