ios - Objective-C:捕获自定义框架内所有 View 的屏幕截图

Question

我有一款游戏，用户可以在其中创建自定义级别并将其上传到我的服务器供其他用户玩，我想在用户测试他/她的级别以上传到我的服务器之前获取“操作区域”的屏幕截图作为一种“预览图像”。

我知道如何获取整个 View 的屏幕截图，但我想将其定义为自定义框架。考虑下图:

我只想截取红色区域“操作区域”的屏幕截图。我能做到吗？

Answer 1

只需要将你想要捕获的区域做成一个矩形，然后在方法中传递这个矩形即可。

swift 3.x:

extension UIView {
  func imageSnapshot() -> UIImage {
    return self.imageSnapshotCroppedToFrame(frame: nil)
  }

  func imageSnapshotCroppedToFrame(frame: CGRect?) -> UIImage {
    let scaleFactor = UIScreen.main.scale
    UIGraphicsBeginImageContextWithOptions(bounds.size, false, scaleFactor)
    self.drawHierarchy(in: bounds, afterScreenUpdates: true)
    var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()

    if let frame = frame {
        let scaledRect = frame.applying(CGAffineTransform(scaleX: scaleFactor, y: scaleFactor))

        if let imageRef = image.cgImage!.cropping(to: scaledRect) {
            image = UIImage(cgImage: imageRef)
        }
    }
    return image
  }
}

//How to call :
imgview.image = self.view.imageSnapshotCroppedToFrame(frame: CGRect.init(x: 0, y: 0, width: 320, height: 100))

Objective-C :

-(UIImage *)captureScreenInRect:(CGRect)captureFrame 
{
    CALayer *layer;
    layer = self.view.layer;
    UIGraphicsBeginImageContext(self.view.bounds.size); 
    CGContextClipToRect (UIGraphicsGetCurrentContext(),captureFrame);
    [layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *screenImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return screenImage;
}

//How to call :
imgView.image = [self captureScreenInRect:CGRectMake(0, 0, 320, 100)];