Taking a screenshot of a specific part of the screen in iOS

Question

I've got a view controller with a button which takes a screenshot of the whole screen when pressed:

@implementation ViewController
-(IBAction)Screenshot {
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenshotimage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(screenshotimage, nil, nil, nil);
}
@end

The Problem : How should I get a screenshot of a specific part of the screen?

i.e. I need the screenshot to be a specific rectangle in the screen and not the whole screen

Any suggestions ?

Thanks

Answer 1

You have two choices:

• You are saying [self.view.layer renderInContext:UIGraphicsGetCurrentContext()]; Instead, say [otherview.layer renderInContext:UIGraphicsGetCurrentContext()]; where otherview is a view you've put in place in advance, containing as subviews all the part of the screen you want to take a screenshot of.

• Or, do it the way you are doing it, but crop (in code) the resulting screenshot image to the region that you want.

Answer 2

Create the image context with just the size of the rectangle you need and "move" around the origin of the coordinate system using CGContextTranslateCTM before you call renderInContext: to have the specific part of the screen drawn into that context.