如何赋予UIImage负面色彩效果

Question

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色效果

Answer 1

这很简单,您必须选择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();