applezqp

- (UIImage *)createGrayCopy:(UIImage *)source
{
    CGSize imageSize = source.size;
    CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceGray();
    size_t bytesPerRow = 0;
    bytesPerRow = imageSize.width * CGColorSpaceGetNumberOfComponents(colorspace);
    CGContextRef context = CGBitmapContextCreate (NULL, imageSize.width, imageSize.height, CGImageGetBitsPerComponent(source.CGImage), bytesPerRow, colorspace, kCGBitmapAlphaInfoMask & kCGImageAlphaNone);
    CGColorSpaceRelease(colorspace);
    if (context == NULL) {
        return nil;

applezqp

- (CALayer *)shadowLayer
{
    CALayer *shadowLayer = [CALayer layer];

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsPath = [paths objectAtIndex:0];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"shadow.png"];
    NSData *imageData = [NSData dataWithContentsOfFile:filePath];
    
    UIImage *shadowImage;