title: NSTextAttachment image not showing when drawing using CoreText
body: <p>For some reason I'm unable to get NSTextAttachment images to draw when using core text, although the same image would display fine when the NSAttributedString is added to an UILabel.</p>
  
  <p>On iOS this rendering will give empty spaces for the NSTextAttachments, for OS X, a placeholder [OBJECT] square image is rendered for each NSTextAttachment instead. Is there something else that needs to be done in order to render images with CoreText?</p>
  
  <p>The rendering code:</p>
  
  <pre><code>CGFloat contextHeight = CGBitmapContextGetHeight(context);
  CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)_attributedString);
  CGPathRef path = CGPathCreateWithRect(CGRectMake(rect.origin.x,
                                                   contextHeight - rect.origin.y - rect.size.height,
                                                   rect.size.width,
                                                   rect.size.height), NULL);
  CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
  CFRelease(framesetter);
  CGPathRelease(path);
  CGContextSaveGState(context);
  CGContextSetTextMatrix(context, CGAffineTransformIdentity);
  CGContextTranslateCTM(context, 0.0f, contextHeight);
  CGContextScaleCTM(context, 1.0f, -1.0f);
  CTFrameDraw(frame, context);
  CGContextRestoreGState(context);
  CFRelease(frame);
  </code></pre>