iOS屏幕截图

//获得屏幕图像

- (UIImage *)imageFromView: (UIView *) theView
{
UIGraphicsBeginImageContext(theView.frame.size);
CGContextRef

context = UIGraphicsGetCurrentContext();

[theView.layer renderInContext:context];
UIImage *

theImage= UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();
return theImage;
}

//获得某个范围内的屏幕图像
- (UIImage *)imageFromView: (UIView *) theView atFrame:(CGRect)r
{
UIGraphicsBeginImageContext(theView.frame.size);
CGContextRef

context= UIGraphicsGetCurrentContext();

CGContextSaveGState(context);
UIRectClip(r);
[theView.layer renderInContext:context];
UIImage *

theImage= UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return theImage;//[self getImageAreaFromImage:theImage atFrame:r];
}