Screenshot Only Part of Screen - Swift

问题:

I'm using this Swift code to take a screenshot of my app:

UIGraphicsBeginImageContextWithOptions(UIScreen.mainScreen().bounds.size, false, 0);
self.view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

How would I go about taking a screenshot of only part of the screen, and not all of it, as I do here?

回答1:

For example if you want to take the screen shot of the UIView rectangle at position (50,50) with height of (100,150).

First set the Image Context to the size of the rectangle. This sets the image size.

UIGraphicsBeginImageContextWithOptions(CGSizeMake(100,150), false, 0);

Now draw the view in this context in such a way that, the visible part of the screenshot starts at (50,50)

self.view.drawViewHierarchyInRect(CGRectMake(-50,-50,view.bounds.size.width,view.bounds.size.height) afterScreenUpdates: true)

This clips the screen shot at (100,150) because we set the size of our context. Now take the UIImage from this.

var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();

回答2:

To snapshot a view containing a UIVisualEffect (Blur/Vibrancy), see my solution here: https://stackoverflow.com/a/33633386/802196

回答3:

I think this is the best Answer to take a shot of part of the screen:

func screenShot() {
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(self.frame.size.width*0.99,self.frame.size.height*0.70), false, 0)
    var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();
    self.view?.drawViewHierarchyInRect(CGRectMake(-01, -01, self.frame.size.width, self.frame.size.height), afterScreenUpdates: true)
    var screenShot  = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
}