在我的应用程序中，我以编程方式从我的相机中获取了图像。它已经很好地获取了，但是当我切换到另一个视图并在那时关闭该视图时，我的图像会自动旋转 -90 度。
并且这种变化仅在第一次发生后才发生，当我换档时没有发生变化意味着图像保持在 -90 度状态，并且仅当我从相机捕获图像时才会发生这种情况。当我从照片库中获取图像时，没有发现任何问题。
下图是我的原图
这是旋转的图像
我不知道为什么会发生这种变化。
【问题讨论】：
标签： ios objective-c iphone xcode camera
您必须使用此功能来旋转相机拍摄的图像
- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingImage:(UIImage *)image
editingInfo:(NSDictionary *)editingInfo
{
image = [self scaleAndRotateImage:image];
[self useImage:image];
[[picker parentViewController] dismissModalViewControllerAnimated:YES];
}
- (void)scaleAndRotateImage:(UIImage *)image
{
int kMaxResolution = 320; // Or whatever
CGImageRef imgRef = image.CGImage;
CGFloat width = CGImageGetWidth(imgRef);
CGFloat height = CGImageGetHeight(imgRef);
CGAffineTransform transform = CGAffineTransformIdentity;
CGRect bounds = CGRectMake(0, 0, width, height);
if (width > kMaxResolution || height > kMaxResolution) {
CGFloat ratio = width/height;
if (ratio > 1) {
bounds.size.width = kMaxResolution;
bounds.size.height = bounds.size.width / ratio;
}
else {
bounds.size.height = kMaxResolution;
bounds.size.width = bounds.size.height * ratio;
}
}
CGFloat scaleRatio = bounds.size.width / width;
CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef));
CGFloat boundHeight;
UIImageOrientation orient = image.imageOrientation;
switch(orient) {
case UIImageOrientationUp: //EXIF = 1
transform = CGAffineTransformIdentity;
break;
case UIImageOrientationUpMirrored: //EXIF = 2
transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0);
transform = CGAffineTransformScale(transform, -1.0, 1.0);
break;
case UIImageOrientationDown: //EXIF = 3
transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationDownMirrored: //EXIF = 4
transform = CGAffineTransformMakeTranslation(0.0, imageSize.height);
transform = CGAffineTransformScale(transform, 1.0, -1.0);
break;
case UIImageOrientationLeftMirrored: //EXIF = 5
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width);
transform = CGAffineTransformScale(transform, -1.0, 1.0);
transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
break;
case UIImageOrientationLeft: //EXIF = 6
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeTranslation(0.0, imageSize.width);
transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
break;
case UIImageOrientationRightMirrored: //EXIF = 7
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeScale(-1.0, 1.0);
transform = CGAffineTransformRotate(transform, M_PI / 2.0);
break;
case UIImageOrientationRight: //EXIF = 8
boundHeight = bounds.size.height;
bounds.size.height = bounds.size.width;
bounds.size.width = boundHeight;
transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
transform = CGAffineTransformRotate(transform, M_PI / 2.0);
break;
default:
[NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];
}
UIGraphicsBeginImageContext(bounds.size);
CGContextRef context = UIGraphicsGetCurrentContext();
if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
CGContextScaleCTM(context, -scaleRatio, scaleRatio);
CGContextTranslateCTM(context, -height, 0);
}
else {
CGContextScaleCTM(context, scaleRatio, -scaleRatio);
CGContextTranslateCTM(context, 0, -height);
}
CGContextConcatCTM(context, transform);
CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef);
UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[self setRotatedImage:imageCopy];
//return imageCopy;
}
【讨论】：
解决这个问题的最简单方法是在didFinishPickingImage 委托中缩放图像。您可以使用以下代码通过导入类“UIImage+ImageScaling.h”来进行扩展。
theImage =[UIImage imageWithImage:image scaledToSizeWithSameAspectRatio:CGSizeMake(400, 300)];// for iphone.
【讨论】：
这个方法对我有用，
- (UIImage*) rotateImageAppropriately:(UIImage*)imageToRotate
{
UIImage* properlyRotatedImage;
CGImageRef imageRef = [imageToRotate CGImage];
if (imageToRotate.imageOrientation == 0)
{
properlyRotatedImage = imageToRotate;
}
else if (imageToRotate.imageOrientation == 3)
{
CGSize imgsize = imageToRotate.size;
UIGraphicsBeginImageContext(imgsize);
[imageToRotate drawInRect:CGRectMake(0.0, 0.0, imgsize.width, imgsize.height)];
properlyRotatedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
else if (imageToRotate.imageOrientation == 1)
{
properlyRotatedImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:1];
}
return properlyRotatedImage;
}
【讨论】：
不好的行为现在在 13.4 中发生了变化。现在以准确的方向捕获图像。
【讨论】：
试试这个属性
@property (nonatomic) CGAffineTransform cameraViewTransform
并旋转 -90 度，然后捕获图像。如果不起作用，请使用 Cocoa Matters 提供的代码。
【讨论】：
如果您仍然需要一些解决方案，请参考 this 链接，我在其中发布了我对这个问题的答案，只需参考编辑和编辑 1 还可以查看最后 2 或 3 个 cmets 以供进一步参考
【讨论】：
这是由于您的图像方向。所以保持原始图像方向。您将在 UIImagePickerController 委托方法中获得图像方向
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
示例代码：
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
UIImage *sourceImage = [info valueForKey:UIImagePickerControllerOriginalImage];
NSData *data = UIImagePNGRepresentation(sourceImage);
UIImage *tmp = [UIImage imageWithData:data];
UIImage *afterFixingOrientation = [UIImage imageWithCGImage:tmp.CGImage
scale:sourceImage.scale
orientation:sourceImage.imageOrientation];
[self.imagePickerController dismissViewControllerAnimated:YES completion:nil];
}
【讨论】：