Question

Is there a way to take advantage of the device modifiers ~ipad, ~iphone, @2x, for images stored in the cache or documents. As far as I can tell it only works if the files are stored in the main bundle.

NSArray *cachePaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *cachePath = ([cachePaths count] > 0) ? [cachePaths objectAtIndex:0] : nil;
NSString *cacheResourcesPath = [cachePath stringByAppendingPathComponent:@"Resources"];

NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *documentPath = ([documentPaths count] > 0) ? [documentPaths objectAtIndex:0] : nil;
NSString *documentsResourcesPath = [documentPath stringByAppendingPathComponent:@"Resources"];

    // SUCCESS (/caches/resources)
    UIImage *image = [UIImage imageWithContentsOfFile:[cacheResourcesPath stringByAppendingPathComponent:@"image~ipad.png"]];

    // FAIL (/caches/resources)
    UIImage *image = [UIImage imageWithContentsOfFile:[cacheResourcesPath stringByAppendingPathComponent:@"image.png"]];

    // SUCCESS (/documents)
    UIImage *image = [UIImage imageWithContentsOfFile:[documentsResourcesPath stringByAppendingPathComponent:@"image~ipad.png"]];

    // FAIL (/documents)
    UIImage *image = [UIImage imageWithContentsOfFile:[documentsResourcesPath stringByAppendingPathComponent:@"image.png"]];

    // SUCCESS (main bundle)
    UIImage *image = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"image" ofType:@"png"]];

    // SUCCESS (main bundle)
    UIImage *image = [UIImage imageNamed:@"image"];

Answer 1

I’m quite sure that the imageWithContentsOfFile: method does not analyze the file name. I had the same issue back on iPhone when I tried to load some @2x images which were not part of the bundle. In the end I had to use the initWithCGImage:scale:orientation: to be able to set the scale properly. Based on that, I would be surprised if it could handle the ~ipad suffix.