项目需求

根据服务器端返回的参数，更改图片的颜色并保留透明度，点击查看Android下如何操作。

更改颜色

UIImage* originalImage = [UIImage imageNamed:@"btn_right_arrow_circled"];
UIImage* newImage = [Utils changeColor:[Utils colorOfHexString:color] ofImage:originalImage];

相关函数

+ (UIImage*)changeColor:(UIColor*)color ofImage:(UIImage*)image {
    UIGraphicsBeginImageContext (image.size);
    CGRect rect = CGRectMake (0, 0, image.size.width, image.size.height);

    UIGraphicsBeginImageContext (rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext ();
    CGContextSaveGState (context);

    [color setFill];
    CGContextFillRect (context, rect);

    //一定要将BlendMode设置为kCGBlendModeDestinationIn
    CGContextSetBlendMode (context, kCGBlendModeDestinationIn);
    [image drawInRect:rect blendMode:kCGBlendModeDestinationIn alpha:1];

    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext ();

    UIGraphicsEndImageContext ();

    return newImage;
}