Roating CGImageRef on iOS.
For reminder to myself, rotate image on center. CGImageRef imageref = [self imageFromSampleBuffer:sampleBuffer]; // or any other CGImageRef source. int w = CGImageGetWidth(imageref); int h = CGImageGetHeight(imageref); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageref); CGContextRef bitmap = CGBitmapContextCreate(NULL, w, h, CGImageGetBitsPerComponent(imageref), CGImageGetBytesPerRow(imageref), colorSpaceInfo, CGImageGetBitmapInfo(imageref)); CGContextTranslateCTM(bitmap, w/2, h/2); CGContextRotateCTM(bitmap, M_PI_4); CGContextTranslateCTM(bitmap, -w/2, -h/2; CGContextDrawImage(bitmap, CGRectMake(0, 0, w, h), imageref); CGImageRelease(imageref); imageref = CGBitmapContextCreateImage(bitmap); CGContextRelease(bitmap); return imagereff;