截图代码

返回的图片是UIImage,截图区域要乘以2，因为是 CGImageRef 截图，按像素来得（应该是retina屏的原因）

- (UIImage *)snapshotTakeCarView:(UIScrollView *)view count:(int)count
{
    UIImage* image = nil;
    
    UIGraphicsBeginImageContextWithOptions(view.contentSize, YES, 0);
    {
        CGPoint savedContentOffset = view.contentOffset;
        CGRect savedFrame = view.frame;
        
        view.contentOffset = CGPointZero;
        view.frame = CGRectMake(0, 0, view.contentSize.width, view.contentSize.height-70);
        
        [view.layer renderInContext: UIGraphicsGetCurrentContext()];
        image = UIGraphicsGetImageFromCurrentImageContext();
        
        view.contentOffset = savedContentOffset;
        view.frame = savedFrame;
    }
    UIGraphicsEndImageContext();
    CGImageRef imageRef = image.CGImage;
    CGRect rect =CGRectMake(0,60 ,view.contentSize.width*2, view.contentSize.height*2-208);//这里可以设置想要截图的区域，
    CGImageRef imageRefRect =CGImageCreateWithImageInRect(imageRef, rect);
    UIImage *sendImage = [[UIImage alloc] initWithCGImage:imageRefRect];
    CGImageRelease(imageRefRect);
    return sendImage;
}