ios 抓图实现

1. //获得屏幕图像  
2. - (UIImage *)imageFromView: (UIView *) theView    
3. {  
4.       
5.     UIGraphicsBeginImageContext(theView.frame.size);  
6.     CGContextRef context = UIGraphicsGetCurrentContext();  
7.     [theView.layer renderInContext:context];  
8.     UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();  
9.     UIGraphicsEndImageContext();  
10.       
11.     return theImage;  
12. }  
13.  
14. //获得某个范围内的屏幕图像  
15. - (UIImage *)imageFromView: (UIView *) theView   atFrame:(CGRect)r  
16. {  
17.     UIGraphicsBeginImageContext(theView.frame.size);  
18.     CGContextRef context = UIGraphicsGetCurrentContext();  
19.     CGContextSaveGState(context);  
20.     UIRectClip(r);  
21.     [theView.layer renderInContext:context];  
22.     UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();  
23.     UIGraphicsEndImageContext();  
24.       
25.     return  theImage;//[self getImageAreaFromImage:theImage atFrame:r];  
26. }