旋转从视频帧中获取的CGImage [英] Rotate CGImage taken from video frame

问题描述

这是Apple的代码（来自Technical Q& A 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。如何编辑它以便返回的图像正确定位？

This is Apple's code (from Technical Q&A QA1702) for getting a UIImage from a video buffer. Unfortunately, the image returned is rotated 90 degrees. How do I edit this so that the image returned is correctly oriented?

- (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);
}

推荐答案

取决于您是否使用前置摄像头或后置摄像头

Depends on whether you are using the front camera or the back camera

int frontCameraImageOrientation = UIImageOrientationLeftMirrored;
int backCameraImageOrientation = UIImageOrientationRight;

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

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