CGImageRef YYCGImageCreateCopyWithOrientation()

in iOS/WAStickersThirdParty/YYImageCoder.m [1009:1063]
51 lines of code
12 McCabe index (conditional complexity)

CGImageRef YYCGImageCreateCopyWithOrientation(CGImageRef imageRef, UIImageOrientation orientation, CGBitmapInfo destBitmapInfo) {
    if (!imageRef) return NULL;
    if (orientation == UIImageOrientationUp) return (CGImageRef)CFRetain(imageRef);
    
    size_t width = CGImageGetWidth(imageRef);
    size_t height = CGImageGetHeight(imageRef);
    
    CGAffineTransform transform = CGAffineTransformIdentity;
    BOOL swapWidthAndHeight = NO;
    switch (orientation) {
        case UIImageOrientationDown: {
            transform = CGAffineTransformMakeRotation(YYImageDegreesToRadians(180));
            transform = CGAffineTransformTranslate(transform, -(CGFloat)width, -(CGFloat)height);
        } break;
        case UIImageOrientationLeft: {
            transform = CGAffineTransformMakeRotation(YYImageDegreesToRadians(90));
            transform = CGAffineTransformTranslate(transform, -(CGFloat)0, -(CGFloat)height);
            swapWidthAndHeight = YES;
        } break;
        case UIImageOrientationRight: {
            transform = CGAffineTransformMakeRotation(YYImageDegreesToRadians(-90));
            transform = CGAffineTransformTranslate(transform, -(CGFloat)width, (CGFloat)0);
            swapWidthAndHeight = YES;
        } break;
        case UIImageOrientationUpMirrored: {
            transform = CGAffineTransformTranslate(transform, (CGFloat)width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
        } break;
        case UIImageOrientationDownMirrored: {
            transform = CGAffineTransformTranslate(transform, 0, (CGFloat)height);
            transform = CGAffineTransformScale(transform, 1, -1);
        } break;
        case UIImageOrientationLeftMirrored: {
            transform = CGAffineTransformMakeRotation(YYImageDegreesToRadians(-90));
            transform = CGAffineTransformScale(transform, 1, -1);
            transform = CGAffineTransformTranslate(transform, -(CGFloat)width, -(CGFloat)height);
            swapWidthAndHeight = YES;
        } break;
        case UIImageOrientationRightMirrored: {
            transform = CGAffineTransformMakeRotation(YYImageDegreesToRadians(90));
            transform = CGAffineTransformScale(transform, 1, -1);
            swapWidthAndHeight = YES;
        } break;
        default: break;
    }
    if (CGAffineTransformIsIdentity(transform)) return (CGImageRef)CFRetain(imageRef);
    
    CGSize destSize = {width, height};
    if (swapWidthAndHeight) {
        destSize.width = height;
        destSize.height = width;
    }
    
    return YYCGImageCreateAffineTransformCopy(imageRef, transform, destSize, destBitmapInfo);
}