很简单的一个功能，但是长时间不用就忘了，所以放在这里当做笔记好了。
//根据一个View生成一个image
- (UIImage *)screenshotForView:(UIView *)view {
UIImage *image = nil;
//判断View类型（一般不是滚动视图或者其子类的话内容不会超过一屏，当然如果超过了也可以通过修改frame来实现绘制）
if ([view.class isSubclassOfClass:[UIScrollView class]]) {
UIScrollView *scrView = (UIScrollView *)view;
CGPoint tempContentOffset = scrView.contentOffset;
CGRect tempFrame = scrView.frame;
scrView.contentOffset = CGPointZero;
scrView.frame = CGRectMake(0, 0, scrView.contentSize.width, scrView.contentSize.height);
image = [self screenshotForView:scrView size:scrView.frame.size];
scrView.contentOffset = tempContentOffset;
scrView.frame = tempFrame;
} else {
image = [self screenshotForView:view size:view.frame.size];
}
return image;
}
- (UIImage *)screenshotForView:(UIView *)view size:(CGSize)size {
UIImage *image = nil;
UIGraphicsBeginImageContextWithOptions(size, YES, [UIScreen mainScreen].scale);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
