UISnapshotting(快照/截图)

API:

- (UIView *)snapshotView
- (UIView *)resizableSnapshotViewFromRect:(CGRect)rect
            withCapInsets:(UIEdgeInsets)capInsets
- (BOOL)drawViewHierarchyInRect:(CGRect)rect

效能：

比旧的renderinContext方法更优

Snip20181206_2.png

DEMO

创建模糊背景

UIGraphicsBeginImageContextWithOptions(image.size,
NULL, 0);
[view drawViewHierarchyInRect:rect];
UIImage *newImage =
UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
lightImage = [newImage applyLightEffect];

Snip20181206_3.png Snip20181206_4.png