UIScrollView,UIView转换UIImage代码(整个view截图, 不只是可视区域)

-(UIImage*)captureView:(UIView *)theView{
CGRect rect = theView.frame;
if ([theView isKindOfClass:[UIScrollView class]]) {
rect.size = ((UIScrollView *)theView).contentSize;
}

UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[theView.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}

- (UIImage *)captureScrollView:(UIScrollView *)scrollView{
UIImage* image = nil;
UIGraphicsBeginImageContext(scrollView.contentSize);
{
CGPoint savedContentOffset = scrollView.contentOffset;
CGRect savedFrame = scrollView.frame;
scrollView.contentOffset = CGPointZero;
scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);

[scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();

scrollView.contentOffset = savedContentOffset;
scrollView.frame = savedFrame;
}
UIGraphicsEndImageContext();

if (image != nil) {
return image;
}
return nil;
}

- (IBAction) renderScrollViewToImage
{
UIImage* image = nil;

UIGraphicsBeginImageContext(_scrollView.contentSize);
{
CGPoint savedContentOffset = _scrollView.contentOffset;
CGRect savedFrame = _scrollView.frame;

_scrollView.contentOffset = CGPointZero;
_scrollView.frame = CGRectMake(0, 0, _scrollView.contentSize.width, _scrollView.contentSize.height);

[_scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();

_scrollView.contentOffset = savedContentOffset;
_scrollView.frame = savedFrame;
}
UIGraphicsEndImageContext();

if (image != nil) {
[UIImagePNGRepresentation(image) writeToFile: @"/tmp/test.png" atomically: YES];
system("open /tmp/test.png");
}
}