如何给UIImage消色效果

这是我的第一个问题。
我有一个应用程序，我想改变图像效果看起来像负面的颜色效果

Answer 1

这是如此简单，你必须select图像，并在下面的代码中设置图像

UIGraphicsBeginImageContext(renderImage.size); CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy); [renderImage drawInRect:CGRectMake(0, 0, renderImage.size.width, renderImage.size.height)]; CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeDifference); CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(),[UIColor whiteColor].CGColor); CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, renderImage.size.width, renderImage.size.height)); renderImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); 

Answer 2

制作一个方法：

  - (UIImage *)makeImageNegative:(UIImage *)image{ UIGraphicsBeginImageContext(image.size); CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy); [image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)]; CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeDifference); CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(),[UIColor whiteColor].CGColor); CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, image.size.width, image.size.height)); UIImage *returnImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return returnImage; }