UIGraphicsBeginImageContext with parameters

Question

I am taking a screenshot in my application. I am able to take the screenshot.

Now I want to take the screenshot by specifying the x and y coordinate. Is that possible?

UIGraphicsBeginImageContext( self.view.bounds.size );
[self.view.layer renderInContext:UIGraphicsGetCurrentContext(  )];
UIImage* aImage = UIGraphicsGetImageFromCurrentImageContext(  );

score 19 · Accepted Answer · edited Apr 03 '12 at 22:25

19

UIGraphicsBeginImageContext(self.view.bounds.size);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(c, 0, -40);    // <-- shift everything up by 40px when drawing.
[self.view.layer renderInContext:c];
UIImage* viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

edited Apr 03 '12 at 22:25

pixelfreak

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answered Nov 16 '10 at 13:16

kennytm

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@barbgal: Use CGContextScaleCTM to resize. Also, you may need a smaller context (change the argument to UIGraphicsBeginImageContext). – kennytm Nov 16 '10 at 13:31
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@Barbgal: No. `CGSize size=self.view.bounds.size; UIGraphicsBeginImageContext(CGSizeMake(size.width,size.height-40)); CGContextRef c = UIGraphicsGetCurrentContext();` – kennytm Nov 16 '10 at 13:40

score 2 · Answer 2 · answered Sep 01 '14 at 17:19

If you're using a newer retina display device, your code should factor in the resolution by using UIGraphicsBeginImageContextWithOptions instead of UIGraphicsBeginImageContext:

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,YES,2.0);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(c, 0, -40);    // <-- shift everything up by 40px when drawing.
[self.view.layer renderInContext:c];
UIImage* viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

This will render the retina display image context.

score 0 · Answer 3 · answered Sep 22 '15 at 11:10

Just do something like this, way easier than all those complex calculations

+ (UIImage *)imageWithView:(UIView *)view {
    UIGraphicsBeginImageContextWithOptions([view bounds].size, NO, [[UIScreen mainScreen] scale]);

    [[view layer] renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *result = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return result;
}

score 0 · Answer 4 · answered Mar 04 '16 at 18:27

Here is Swift version

//Capture Screen
func capture()->UIImage {

    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, false, UIScreen.mainScreen().scale)
    self.view.layer.renderInContext(UIGraphicsGetCurrentContext()!)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image

}

score 0 · Answer 5 · answered Jun 29 '16 at 07:31

swift version

    UIGraphicsBeginImageContext(self.view.bounds.size)
    let image: CGContextRef = UIGraphicsGetCurrentContext()!
    CGContextTranslateCTM(image, 0, -40)
    // <-- shift everything up by 40px when drawing.
    self.view.layer.renderInContext(image)
    let viewImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil)

UIGraphicsBeginImageContext with parameters

5 Answers5

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