我正在尝试编辑捕获的图像并将其保存到图库.我做了
UIImagePickerController *picker=[[UIImagePickerController alloc] init]; picker.allowsEditting=YES;
我想将图像保存在可编辑的方形部分并将其保存到图库.我知道我可以使用[info objectForKey：@“UIImagePickerControllerEditedImage”]来保存编辑过的图像.但这总是让我看到尺寸为320×320(iPad Mini)的图像,图像质量很差.所以我打算使用以下代码裁剪原始图像[info objectForKey：@“UIImagePickerControllerOriginalImage”]：
CGRect rect = [[info objectForKey:@"UIImagePickerControllerCropRect"]CGRectValue];
UIImage *originalImage=[info objectForKey:@"UIImagePickerControllerOriginalImage"];
CGImageRef imageRef = CGImageCreateWithImageInRect([originalImage CGImage],rect);
UIImage *result = [UIImage imageWithCGImage:imageRef
scale:originalImage.scale
orientation:originalImage.imageOrientation];
CGImageRelease(imageRef);
然后我保存了结果图像和编辑图像([info objectForKey：@“UIImagePickerControllerEditedImage”]).当比较两个图像时,它们匹配.我附加了编辑和裁剪的图像.我的最终目标是将原始图像裁剪为可编辑方形部分中的图像,并将其保存到具有良好图像质量的图库中.谁能告诉我这里到底出了什么问题并帮我解决这个问题？
提前致谢.
解决方法
我发现了种植错误的原因. UIImagePickerControllerOriginalImage返回的图像旋转到-90度.因此,在旋转的图像上裁剪会返回错误的裁剪图像.所以我将图像旋转到90度然后裁剪它.最后我得到了预期的裁剪图像,质量很好.以下代码解决了我的问题.
UIImage *originalImage = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
CGRect rect=[[info objectForKey:@"UIImagePickerControllerCropRect"]CGRectValue];
UIImage *rotatedOriginalImage=[originalImage imageRotatedByDegrees:90.0];
CGImageRef imageRef = CGImageCreateWithImageInRect([rotatedOriginalImage CGImage],rect) ;
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
用于旋转图像的代码：
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees{
// calculate the size of the rotated view's containing Box for our drawing space
UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,self.size.height,self.size.width)];
CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
rotatedViewBox.transform = t;
CGSize rotatedSize = rotatedViewBox.frame.size;
// Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize);
CGContextRef bitmap = UIGraphicsGetCurrentContext();
// Move the origin to the middle of the image so we will rotate and scale around the center.
CGContextTranslateCTM(bitmap,rotatedSize.width/2,rotatedSize.height/2);
// // Rotate the image context
CGContextRotateCTM(bitmap,DegreesToRadians(degrees));
// Now,draw the rotated/scaled image into the context
CGContextScaleCTM(bitmap,1.0,-1.0);
CGContextDrawImage(bitmap,CGRectMake(-self.size.height / 2,-self.size.width / 2,self.size.width),[self CGImage]);
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
