圖像裁剪問題

Question

我已經編寫了下面的代碼來裁剪橢圓形圖像。但沒有得到預期的結果。原始圖像大小是382x453。並在CGRectMake（50,100,100,150）上進行日食。但圖像總是從原始圖像的0,0位置裁剪。我在這段代碼中做了許多事情。請幫我解決我錯在哪裏。非常感謝，Ghufran

CGSize croppedSize = CGSizeMake(100, 150); 
CGRect clippedRect = CGRectMake(0, 0, croppedSize.width, croppedSize.height); 
UIGraphicsBeginImageContext(croppedSize); 
CGContextBeginPath(UIGraphicsGetCurrentContext()); 
CGContextAddEllipseInRect(UIGraphicsGetCurrentContext(), clippedRect); 
CGContextClosePath(UIGraphicsGetCurrentContext()); 
CGContextClip(UIGraphicsGetCurrentContext()); 
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), 0, croppedSize.height); 
CGContextScaleCTM(UIGraphicsGetCurrentContext(), 1.0, -1.0); 
CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(clippedRect.origin.x * -1, clippedRect.origin.y * -1, mImage.size.width, mImage.size.height), mImage.CGImage); 
//pull the image from our cropped context 
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext(); 

Answer 1

我認爲原點（50,100）需要反映在resedRect的矩形中。

CGRect clippedRect = CGRectMake(0, 0, croppedSize.width, croppedSize.height); 

成爲

CGRect clippedRect = CGRectMake(50, 100, croppedSize.width, croppedSize.height);