Resizing an image with stretchableImageWithLeftCapWidth

Question

I'm trying to resize an image using stretchableImageWithLeftCapWidth: it works on the simulator, but on the device, vertical green bars appears.

I've tried to use imageNamed, imageWithContentOfFile and imageWithData lo load the image, it doesnt change.

UIImage *bottomImage = [[UIImage imageWithData:
     [NSData dataWithContentsOfFile:
    [NSString stringWithFormat:@"%@/bottom_part.png", 
     [[NSBundle mainBundle] resourcePath]]]] 
       stretchableImageWithLeftCapWidth:27 topCapHeight:9];

UIImageView *bottomView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 200+73, 100, 73)];
[self.view addSubview:bottomView];
UIGraphicsBeginImageContext(CGSizeMake(100, 73));
[bottomImage drawInRect:CGRectMake(0, 0, 100, 73)];
UIImage *bottomResizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
bottomView.image = bottomResizedImage;

See the result: the green bars shouldn't be there, they dont appear on the simulator.

alt text http://www.quicksnapper.com/files/5161/96232162149F1C14751048_m.png

Answer 1

Did you figure this out?

Seems like it might be a bug with UIGraphicsGetImageFromCurrentImageContext. If I draw an image that has transparency I get red/green artifacts. These only appear on the device (not in the sim). Also, if I remove transparency from the image, the artifacts go away.

Update: Some more weirdness. I was using PNGs before, so I tried using a transparent gif instead. Using a GIF, shows the artifact problem on the sim.

Victory! Found a solution:

Turn off 'Compress PNG Files' in the build settings for your project. Disabling this makes the PNG transparency work without any artifacts.

Answer 2

It seems like you're writing a lot of unnecessary code, but perhaps that's just because it's out of context and there's more to it that I'm missing.

To get the image:

[[UIImage imageName: @"bottom_part.png"] stretchableImageWithLeftCapWidth: 27 topCapHeight: 9];

What part of your code are you displaying this image? i.e. in what method call are you drawing the images above?

Why not just use a UIImageView and put the image in there? Then you don't need to do any of the image context drawing etc.