大图片中截取其中一部分小图显示 两图合成一图［转载］

- (UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2 {     

 UIGraphicsBeginImageContext(image1.size);          // Draw image1          

 [image1 drawInRect:CGRectMake(0, 0, image1.size.width, image1.size.height)];          // Draw image2         

 [image2 drawInRect:CGRectMake(0, 0, image2.size.width, image2.size.height)];      

 UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();     

 UIGraphicsEndImageContext();            

 return resultingImage; 

}

大图中间截取小图

#define     PhotoWidth                  220 

#define     PhotoHeight                 107  

-(UIImage *)getNewImage:(UIImage *)image {    

 UIImage *tempImage = image;           

 CGImageRef imgRef = tempImage.CGImage;    

 CGRect   rect1 = CGRectMake((tempImage.size.width-PhotoWidth)/2,(tempImage.size.height-PhotoHeight)/2, PhotoWidth, PhotoHeight);     

 CGImageRef img=CGImageCreateWithImageInRect(imgRef,rect1);          

 UIImage *newImage = [UIImage imageWithCGImage:img];     

 CGImageRelease(img);         

 return newImage; 

 }