如何給UIImage帶來負面的色彩效果

Question

這是我的第一個問題。
我有，我想改變圖像效果看起來像彩色負片效果的應用

Answer 1

它是如此簡單，你必須選擇圖像，並在下面的代碼

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

製作的方法設置圖像：

- (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; 
}