Blend overlay

blendoverlay.m

- (UIImage *)blendOverlay:(UIImage *)topImage withBaseImage:(UIImage *)baseImage toSize:(CGFloat)imageSize
{
    UIGraphicsBeginImageContext(CGSizeMake(imageSize, imageSize));
    [baseImage drawInRect:CGRectMake(0.0, 0.0, imageSize, imageSize)];
    [topImage drawInRect:CGRectMake(0.0, 0.0, imageSize, imageSize) blendMode:kCGBlendModeNormal alpha:0.5];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}