Drawing transparent images?

[Björn Giesler]

Hi,

I'm trying to create a transparent NSImage from my program, but all I get is a 
grey block, and I can't draw in the resulting NSImage. This is my code: 

  NSImage *image; NSBitmapImageRep *rep;
  NSMutableAttributedString *str;
  NSSize size;

  str = [[NSAttributedString alloc] initWithString: @"Hello"];
  size = [str size];
  image = [[[NSImage alloc] initWithSize: size] autorelease];
  rep = [[[NSBitmapImageRep alloc] initWithBitmapDataPlanes: NULL
                                   pixelsWide: size.width
                                   pixelsHigh: size.height
                                   bitsPerSample: 8
                                   samplesPerPixel: 4
                                   hasAlpha: YES
                                   isPlanar: YES
                                   colorSpaceName: NSCalibratedRGBColorSpace
                                   bytesPerRow: 0
                                   bitsPerPixel: 0] autorelease];
  [image addRepresentation: rep];
  [image lockFocus];
  [[NSColor clearColor] set];
  NSRectFill(NSMakeRect(0, 0, size.width, size.height));
  [[NSColor blackColor] set];
  [str drawAtPoint: NSZeroPoint];
  
All I get is a grey box. If I pass hasAlpha: NO, I get a grey box with some 
text on it, but it's still grey, not transparent.

Is this a known bug?

Regards,
Björn