UIImage渲染颜色

有时候，我们需要改变图片的颜色，如图片中有白色字体，我们要把它改成黑色，这时候我们要对UIImageView渲染颜色。代码如下

参数image是原图，color是要渲染的颜色

CGContext的纵坐标和UIKit的纵坐标相反，所以要做坐标变换，原图的左下角是原点，每点的纵坐标取反

+ (UIImage *)imageWithImage:(UIImage *)image tintColor:(UIColor *)color {

    UIGraphicsBeginImageContextWithOptions(image.size,NO, image.scale);

    CGContextRef context =UIGraphicsGetCurrentContext();

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

    CGContextScaleCTM(context, 1, -1);

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

    CGContextClipToMask(context, rect, image.CGImage);

    UIRectFillUsingBlendMode(rect,kCGBlendModeNormal);

    UIImage *newImage =UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return newImage;

}