title: NSRectFill draws twice as big on retina MBP
body: <p>I am trying to draw and save a simple image, but it is ultimately saved twice as big on a MBP RD device:</p>
  
  <pre><code>NSImage* image = [[NSImage alloc] initWithSize:size];
  [image lockFocus];
  
  [[NSColor blueColor] set];
  NSRectFill(CGRectMake(0, 0, 100, 100));
  
  [image unlockFocus];
  
  // ... then save the image
  
  // Cache the reduced image
  NSData *imageData = [self TIFFRepresentation];
  NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepWithData:imageData];
  NSDictionary *imageProps = [NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:1.0] forKey:NSImageCompressionFactor];
  imageData = [imageRep representationUsingType:NSPNGFileType properties:imageProps];
  [imageData writeToFile:fileName atomically:NO];
  
  // image is saved as 200 x 200 :(
  </code></pre>
  
  <p>I would like to have a consistent size, so 100x100 on all devices</p>