CGContextRotateCTM is not showing anything

- (void)drawRect:(CGRect)rect {
    // Drawing code.
    stickerImage = [UIImage imageNamed:@"betaImage.png"];
    CGSize size = stickerImage.size;
    UIGraphicsBeginImageContext(size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextTranslateCTM( con开发者_开发技巧text, 0.5f * size.width, 0.5f * size.height );
    CGContextRotateCTM (context, 90 * M_PI/180);
    [stickerImage drawInRect:(CGRect){ { -size.width * 0.5f, -size.height * 0.5f }, size }];

    UIGraphicsEndImageContext();
}

I just cannot find whats wrong with my code, it does not showing anything

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Don't begin and end an image context - that's for drawing to a UIImage. The current context has already been set to the view's context in drawRect - UIGraphicsGetCurrentContext() will give the right context out of the box.

In other words - get rid of UIGraphicsBeginImageContext() and UIGraphicsEndImageContext().

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Yep, you shouldn't end your context before you get the result image. In your code example you should get the result image:

UIImage* yourImage = UIGraphicsGetImageFromCurrentImageContext();

or just pass ending context to other parent methods;

As Morgan Harris said, all image manipulations should be between UIGraphicsBeginImageContext() and UIGraphicsEndImageContext();