改變UIImage的顏色

資料來源

簡單說就是..底下的函式.
丟一個 UIImage進去,回傳一個填上顏色的UIImage回來

- (UIImage*)getRedImage:(UIImage*)img{

    UIGraphicsBeginImageContext(img.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);

    CGContextTranslateCTM(context, 0, img.size.height);

    CGContextScaleCTM(context, 1.0, -1.0);

    CGRect rect = CGRectMake(0, 0, img.size.width, img.size.height);

    CGContextDrawImage(context, rect, img.CGImage);

    CGContextClipToMask(context, rect, img.CGImage);

    CGContextAddRect(context, rect);

    CGContextDrawPath(context,kCGPathFill);

    UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return coloredImg;

}