is the underlying bug also responsible for the fact that the following method (works on OS X) to get the pixel data of a NSImage doesn't work - or should i file a separate bug?


NSImage *theImg = [[NSImage alloc] initWithContentsOfURL:_url];
NSBitmapImageRep* bitmap = [NSBitmapImageRep alloc];
NSSize imgSize = [theImg size];


[theImg lockFocus];
[bitmap initWithFocusedViewRect:NSMakeRect(0.0, 0.0, imgSize.width, imgSize.height)];
[theImg unlockFocus];

char _data = (char )calloc( imgSize.width 4 imgSize.height, 1);              
memcpy(_data, [bitmap bitmapData], imgSize.width 4 imgSize.height);

Thanks for reporting.

As a workaround, you can get it to work by adding the view you snapshot to the window content view before taking the snapshot, and ordering-front the window before taking the snapshot.

-[NSView bitmapImageRepForCachingDisplayInRect:] and -[NSView cacheDisplayInRect:toBitmapImageRep:] probably shouldn't rely on being able to lock focus on the view (self), but rather should use [NSGraphicsContext graphicsContextWithBitmapImageRep:] to create a context which can draw directly on the bitmap, and then just call the view's display method. The only problem is, [NSGraphicsContext graphicsContextWithBitmapImageRep:] isn't implemented currently.

Another potential bug this revealed is it seems you can't lock focus on a view before its window has been ordered front... that sounds wrong to me.