如何采取UIScrollView的可视区域的屏幕截图？(How to take screenshot

如何采取1：UIScrollView的可视面积的1截图？ 内容可能比UIScrollView的范围更大或更小以及半隐藏的（我已经实现自定义的滚动较小内容，所以它不是在左上角）。 我所取得的模拟器期望的结果，而不是设备本身：

-(UIImage *)imageFromCombinedContext:(UIView *)background {
      UIImage *image;
      CGRect vis = background.bounds;
      CGSize size = vis.size;
      UIGraphicsBeginImageContext(size);
      [background.layer affineTransform];
      [background.layer renderInontext:UIGraphicsGetCurrentContext()];
      image = UIGraphicsGetImageFromCurrentImageContext();
      UIGraphicsEndImageContext();
      CGImageRef imref = CGImageCreateWithImageInRect([image CGImage], vis);
      image = [UIImage imageWithCGImage:imref];
      CGImageRelease(imref);
      return image;
}

Answer 1:

另一种方法是使用contentOffset调整图层的可见区域， 只捕获的当前可视区域UIScrollView 。

UIScrollView *contentScrollView;....//scrollview instance

UIGraphicsBeginImageContextWithOptions(contentScrollView.bounds.size, 
                                       YES, 
                                       [UIScreen mainScreen].scale);

//this is the key
CGPoint offset=contentScrollView.contentOffset;
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -offset.x, -offset.y); 

[contentScrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *visibleScrollViewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

干杯:)

Answer 2:

斯威夫特版本Abduliam Rehmanius答案。

func screenshot() -> UIImage {

        UIGraphicsBeginImageContextWithOptions(self.scrollCrop.bounds.size, true, UIScreen.mainScreen().scale);
        //this is the key
        let offset:CGPoint = self.scrollCrop.contentOffset;
        CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -offset.x, -offset.y);
        self.scrollCrop.layer.renderInContext(UIGraphicsGetCurrentContext()!);
        let visibleScrollViewImage: UIImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return visibleScrollViewImage;
    }

斯威夫特4版：

func screenshot() -> UIImage {
UIGraphicsBeginImageContextWithOptions(self.scrollCrop.bounds.size, false, UIScreen.main.scale)
        let offset = self.scrollCrop.contentOffset
        let thisContext = UIGraphicsGetCurrentContext()
        thisContext?.translateBy(x: -offset.x, y: -offset.y)
        self.scrollCrop.layer.render(in: thisContext!)
        let visibleScrollViewImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
return visibleScrollViewImage
}

Answer 3:

我已经找到了解决办法我自己-我把整个视图的屏幕截图，然后将其作物的大小和位置UIScrollView框架。

-(UIImage *)imageFromCombinedContext:(UIView *)background 
{
      UIImage *image;
      CGSize size = self.view.frame.size;
      UIGraphicsBeginImageContext(size);
      [background.layer affineTransform];
      [self.view.layer.layer renderInContext:UIGraphicsGetCurrentContext()];
      image = UIGraphicsGetImageFromCurrentImageContext();
      UIGraphicsEndImageContext();
      CGImageRef imgRef = CGImageCreateWithImageInRect([image CGImage],background.frame);
      image = [UIImage imageWithCGImage:imref];
      CGImageRelease(imref);
      return image;
}

Answer 4:

杰弗里Sun有正确的答案。 只要把你的滚动视图另一个视图中。 获取容器视图在上下文中呈现。 完成。

在下面的代码，cropView包含待捕获的滚动视图。 该解决方案是真的这么简单。

当我明白这个问题，为什么我找到了这个网页，滚动视图的全部内容，不想要的 - 只是有形的部分。

func captureCrop() -> UIImage {
    UIGraphicsBeginImageContextWithOptions(self.cropView.frame.size, true, 0.0)
    self.cropView.layer.renderInContext(UIGraphicsGetCurrentContext())
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image;
}

Answer 5:

斯威夫特4版Abduliam Rehmanius答案为UIScrollView extension与翻译，没有慢裁剪

extension UIScrollView {

    var snapshotVisibleArea: UIImage? {
        UIGraphicsBeginImageContext(bounds.size)
        UIGraphicsGetCurrentContext()?.translateBy(x: -contentOffset.x, y: -contentOffset.y)
        layer.render(in: UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

Answer 6:

@Abduliam Rehmanius的回答有表现不佳，因为如果UIScrollView含有大量的内容方面，我们会得出整个内容区域（连外可视范围）。 @ Concuror的回答有问题，这也将画什么是对的顶部UIScrollView 。

我的解决办法是把UIScrollView一个内部UIView称为containerView具有相同的边界，然后渲染containerView ：

containerView.renderInContext(context)

Answer 7:

雨燕3.0：

 func captureScreen() -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(self.yourScrollViewName.bounds.size, true, UIScreen.main.scale)
    let offset:CGPoint = self.yourScrollViewName.contentOffset;
    UIGraphicsGetCurrentContext()!.translateBy(x: -offset.x, y: -offset.y);
    self.yourScrollViewName.layer.render(in: UIGraphicsGetCurrentContext()!)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}

并把它作为：让图片= captureScreen（）

Answer 8:

更新迅速3+，4 @Concuror代码

func getImage(fromCombinedContext background: UIView) -> UIImage {
        var image: UIImage?
        let size: CGSize = view.frame.size
        UIGraphicsBeginImageContext(size)
        background.layer.affineTransform()
        view.layer.render(in: UIGraphicsGetCurrentContext()!)
        image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        let imgRef = image?.cgImage?.cropping(to: background.frame)
        image = UIImage(cgImage: imgRef!)
        // CGImageRelease(imgRef!) // Removing on Swift - 'CGImageRelease' is unavailable: Core Foundation objects are automatically memory managed
        return image ?? UIImage()
    }

文章来源: How to take screenshot of UIScrollView visible area?