嘿，似乎沒有人覺得在這一個打瞌睡。原來，答案很簡單。經由stillImageOutput captureStillImageAsynchronouslyFromConnection:...方法捕獲圖像總是最終具有以下屬性：
- UIImage的取向=總是UIImageOrientationRight無論裝置的取向的
- UIImage的大小= W x高（例如肖像寬×縱向高度，取決於相機上分辨率）
- CGImage大小=取決於設備取向（例如縱向或橫向）
所以將圖像旋轉了解決方案是使用設備定向結合CGImage大小應用適當的仿射變換。正如我在回答我的問題，我不是在代碼中的解決方案，但我最後寫一個調用的程序：
- (UIImage *)imageRotatedUpForDeviceOrientation:(UIDeviceOrientation)deviceOrientation
包含各種圖像處理功能增強UIImage的類別。
編輯 - 實現示例
我已經收到了一些關於本作的功能代碼的請求。我從一個工作應用程序中提取了相關的實現。
// this method is implemented in your capture session manager (wherever AVCaptureSession is used)
// capture a still image and save the device orientation
- (void)captureStillImage
{
UIDeviceOrientation currentDeviceOrientation = UIDevice.currentDevice.orientation;
[self.stillImageOutput
captureStillImageAsynchronouslyFromConnection:self.videoConnection
completionHandler:^(CMSampleBufferRef imageSampleBuffer, NSError *error) {
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
if (imageData) {
UIImage *image = [UIImage imageWithData:imageData];
NSDictionary *captureInfo = {
@"image" : image,
@"deviceOrientation" : @(currentDeviceOrientation)
};
// TODO: send image & orientation to delegate or post notification to observers
}
else {
// TODO: handle image capture error
}
}];
}
// this method rotates the UIImage captured by the capture session manager based on the
// device orientation when the image was captured
- (UIImage *)imageRotatedUpFromCaptureInfo:(NSDictionary *)captureInfo
{
UIImage *image = [captureInfo objectForKey:@"image"];
UIDeviceOrientation deviceOrientation = [[captureInfo objectForKey:@"deviceOrientation"] integerValue];
UIImageOrientation rotationOrientation = [self rotationNeededForImageCapturedWithDeviceOrientation:deviceOrientation];
// TODO: scale the image if desired
CGSize newSize = image.size;
return [imageScaledToSize:newSize andRotatedByOrientation:rotationOrientation];
}
// return a scaled and rotated an image
- (UIImage *)imageScaledToSize:(CGSize)newSize andRotatedByOrientation:(UIImageOrientation)orientation
{
CGImageRef imageRef = self.CGImage;
CGRect imageRect = CGRectMake(0.0, 0.0, newSize.width, newSize.height);
CGRect contextRect = imageRect;
CGAffineTransform transform = CGAffineTransformIdentity;
switch (orientation)
{
case UIImageOrientationDown: { // rotate 180 deg
transform = CGAffineTransformTranslate(transform, imageRect.size.width, imageRect.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
} break;
case UIImageOrientationLeft: { // rotate 90 deg left
contextRect = CGRectTranspose(contextRect);
transform = CGAffineTransformTranslate(transform, imageRect.size.height, 0.0);
transform = CGAffineTransformRotate(transform, M_PI/2.0);
} break;
case UIImageOrientationRight: { // rotate 90 deg right
contextRect = CGRectTranspose(contextRect);
transform = CGAffineTransformTranslate(transform, 0.0, imageRect.size.width);
transform = CGAffineTransformRotate(transform, 3.0 * M_PI/2.0);
} break;
case UIImageOrientationUp: // no rotation
default:
break;
}
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
CGColorSpaceRef colorSpaceRef = CGImageGetColorSpace(imageRef);
// madify bitmapInfo to work with PNG if necessary
if (bitmapInfo == kCGImageAlphaNone) {
bitmapInfo = kCGImageAlphaNoneSkipLast;
}
else if (bitmapInfo == kCGImageAlphaLast) {
bitmapInfo = kCGImageAlphaPremultipliedLast;
}
// Build a context that's the same dimensions as the new size
CGContextRef context = CGBitmapContextCreate(NULL,
contextRect.size.width,
contextRect.size.height,
CGImageGetBitsPerComponent(imageRef),
0,
colorSpaceRef,
bitmapInfo);
CGContextConcatCTM(context, transform);
CGContextDrawImage(context, imageRect, imageRef);
// Get the rotated image from the context and a UIImage
CGImageRef rotatedImageRef = CGBitmapContextCreateImage(context);
UIImage *rotatedImage = [UIImage imageWithCGImage:rotatedImageRef];
// Clean up
CGImageRelease(rotatedImageRef);
CGContextRelease(context);
return rotatedImage;
}
// return the UIImageOrientation needed for an image captured with a specific deviceOrientation
- (UIImageOrientation)rotationNeededForImageCapturedWithDeviceOrientation:(UIDeviceOrientation)deviceOrientation
{
UIImageOrientation rotationOrientation;
switch (deviceOrientation) {
case UIDeviceOrientationPortraitUpsideDown: {
rotationOrientation = UIImageOrientationLeft;
} break;
case UIDeviceOrientationLandscapeRight: {
rotationOrientation = UIImageOrientationDown;
} break;
case UIDeviceOrientationLandscapeLeft: {
rotationOrientation = UIImageOrientationUp;
} break;
case UIDeviceOrientationPortrait:
default: {
rotationOrientation = UIImageOrientationRight;
} break;
}
return rotationOrientation;
}
不要使用的UIDevice的方向，當你真的想使用UIInterface方向。 – Till
在這種情況下，您不能使用'UIInterface'方向。拍攝圖像時的設備方向始終正確。在捕獲數據之後，「stillImage」的圖像方向不正確。我能夠使用UIDeviceOrientation解決問題，並在旋轉時轉換爲適當的UIImageOrientation。那時候，沒有人在這裏打手勢，所以我沒有發佈代碼。如果我有時間，我會添加代碼。 – XJones
@XJones，請用確切的解決方案更新您的答案。 – Hemang