春水初生，春林初盛，春风十里，不如你。

前言

在开发过程中，不免遇到屏幕截图分享，截图添加水印等。本文就记录一下自己项目中分享截图时写的代码，小白们可以参考一下，大神们请绕行。

• 屏幕截图

UIGraphicsBeginImageContextWithOptions(CGSizeMake(SCREEN_WIDTH, SCREEN_HEIGHT), NO, 0);
CGContextRef ctx = UIGraphicsGetCurrentContext();
[self.view.layer renderInContext:ctx];
 // 这个就是截图
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

• 添加水印

// 画水印  rect：水印图片相对于截图的位置
- (UIImage *)originImage:(UIImage *)originImage withWaterMask:(UIImage *)mask inRect:(CGRect)rect {
    UIGraphicsBeginImageContextWithOptions(originImage.size, NO, 0); // 0.0 for scale means "scale for device's main screen".
    //原图
    [originImage drawInRect:CGRectMake(0, 0, originImage.size.width, originImage.size.height)];
    //水印图
    [mask drawInRect:rect];
    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newPic;
}

• 截取scrollView或者tableView长图

UIImage* viewImage = nil;
UITableView *scrollView = self.tableView;
//我把contentSize.height加了一个值，是因为我要在长图底部添加图片
UIGraphicsBeginImageContextWithOptions(CGSizeMake(scrollView.contentSize.width, scrollView.contentSize.height + kRelativeHeight(121)), scrollView.opaque, 0.0);    
//记录用户点击分享时视图的偏移量、位置
CGPoint savedContentOffset = scrollView.contentOffset;
CGRect savedFrame = scrollView.frame;
//把偏移量置为，从顶部开始截图     
scrollView.contentOffset = CGPointZero;
scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);  
[scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
viewImage = UIGraphicsGetImageFromCurrentImageContext(); 
//恢复到用户点击时的状态    
scrollView.contentOffset = savedContentOffset;
scrollView.frame = savedFrame;
UIGraphicsEndImageContext();