iphone - 旋转从视频帧获取的 CGImage

Question

这是 Apple 的代码(来自技术问答 QA1702)，用于从视频缓冲区获取 UIImage。不幸的是，返回的图像旋转了 90 度。如何编辑它以使返回的图像方向正确？

- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer 
{
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
    CVPixelBufferLockBaseAddress(imageBuffer, 0); 

    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); 

    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
    size_t width = CVPixelBufferGetWidth(imageBuffer); 
    size_t height = CVPixelBufferGetHeight(imageBuffer); 

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

    CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, 
                                                 bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); 

    CGImageRef quartzImage = CGBitmapContextCreateImage(context); 
    CVPixelBufferUnlockBaseAddress(imageBuffer,0);

    CGContextRelease(context); 
    CGColorSpaceRelease(colorSpace);

    UIImage *image = [UIImage imageWithCGImage:quartzImage];

    CGImageRelease(quartzImage);

    return (image);
}

Answer 1

取决于您使用的是前置摄像头还是后置摄像头

int frontCameraImageOrientation = UIImageOrientationLeftMirrored;
int backCameraImageOrientation = UIImageOrientationRight;

UIImage *image = [[UIImage alloc] initWithCGImage:newImage scale:(CGFloat)1.0 orientation:frontCameraImageOrientation];