ios - 为什么要拉伸图像（UIImage to CIImage to UIImage）

Question

由于某些原因，我需要将图像从 UIImage 转换为 CIImage（用于处理）并再次转换回 UIImage。我是通过 UIImage-CGImage-CIImage-UIImage 来做的。忽略不相关的代码，代码显示在后面。

UIImage *originalPic = [[UIImage alloc]init];//get this from UIImagePickerController
CIImage *originalCIPic = [[CIImage alloc]init];
originalCIPic = [CIImage imageWithCGImage:originalPic.CGImage];
UIImage *finalResultUIImage = [UIImage imageWithCIImage:originalCIPic];

//then I put the image on an Image View(contentMode has been set)
self.viewOfImage.contentMode = UIViewContentModeScaleAspectFit; 
self.viewOfImage.image=finalResultUIImage;

//I used NSLog to check the size, but they are the same.(before transforming and after)
NSLog(@"this is the final UIImage,size is %@ ",NSStringFromCGSize(finalResultUIImage.size));

但是屏幕上显示的图像被拉伸了。

我怎么了？或者我有其他选择吗？

非常感谢，我很抱歉我没有足够的声誉来张贴图片。:)

Answer 1

尝试这个：

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"abcd" ofType:@"png"];
CIImage *ciImage = [CIImage imageWithContentsOfURL:[NSURL fileURLWithPath:filePath]];
UIImage *imageByCIImage = [UIImage imageWithCIImage:ciImage scale:1.0f orientation:UIImageOrientationUp];

UIGraphicsBeginImageContext(imageByCIImage.size);
[imageByCIImage drawInRect:CGRectMake(0,0,imageByCIImage.size.width,imageByCIImage.size.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
self.imageview.image = newImage;
UIGraphicsEndImageContext();