添加图片水印

#pragma mark 水印

-(UIImage *)addImageLogo:(UIImage *)img text:(UIImage *)logo

{

    //get image width and height

    int w = img.size.width;

    int h = img.size.height;

    int logoWidth = logo.size.width;

    int logoHeight = logo.size.height;

    CGColorSpaceRef colorSpace =CGColorSpaceCreateDeviceRGB();

    //create a graphic context with CGBitmapContextCreate

    CGContextRef context =CGBitmapContextCreate(NULL, w, h,8, 4 * w, colorSpace,kCGImageAlphaPremultipliedFirst);

    CGContextDrawImage(context,CGRectMake(0,0, w, h), img.CGImage);

    CGContextDrawImage(context,CGRectMake(w-logoWidth, 8, logoWidth, logoHeight), [logoCGImage]);

    CGImageRef imageMasked =CGBitmapContextCreateImage(context);

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

    return [UIImageimageWithCGImage:imageMasked];

    //  CGContextDrawImage(contextRef, CGRectMake(100, 50, 200, 80), [smallImg CGImage]);

}