iOS 截取指定区域并获取UIImage

截取view指定区域

- (UIImage*)imageFromView:(UIView *)view rect:(CGRect)rect
{
    UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, 1.0);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    CGRect myImageRect = rect;
    CGImageRef imageRef = image.CGImage;
    CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef,myImageRect );
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextDrawImage(context, myImageRect, subImageRef);
    UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
    CGImageRelease(subImageRef);
    UIGraphicsEndImageContext();
    
    return smallImage;
}

截取web指定区域

- (UIImage*)captureView:(UIView *)theView frame:(CGRect)frame
{
    UIGraphicsBeginImageContext(theView.frame.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    UIImage *img;
    if([[[UIDevice currentDevice] systemVersion] floatValue]>=7.0)
    {
        for(UIView *subview in theView.subviews)
        {
            [subview drawViewHierarchyInRect:subview.bounds afterScreenUpdates:YES];
        }
        img = UIGraphicsGetImageFromCurrentImageContext();
    }
    else
    {
        CGContextSaveGState(context);
        [theView.layer renderInContext:context];
        img = UIGraphicsGetImageFromCurrentImageContext();
    }
    UIGraphicsEndImageContext();
    CGImageRef ref = CGImageCreateWithImageInRect(img.CGImage, frame);
    UIImage *CGImg = [UIImage imageWithCGImage:ref];
    CGImageRelease(ref);
    return CGImg;
}