swift - 使用 Swift 将 Image 上下文设置为 ScreenShot 的 subview

Question

我想捕获属于堆栈 View 一部分的 View 中的图像(屏幕截图)(这里是ResultsView)。因为我使用堆栈 View 来重新定位两个 View ，所以我需要使用 ResultsView View 来捕获图像(即我无法使用屏幕上的地理位置)。

我最终的结果要么是整体，要么是部分，使用一些屏幕位置:

    // full screen shot
    UIGraphicsBeginImageContext(view.frame.size)
    view.layer.render(in: UIGraphicsGetCurrentContext()!)
    let sourceImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    //print("ScreenShot")
    //UIImageWriteToSavedPhotosAlbum(sourceImage!, nil, nil, nil)

    // partial screen shot
    UIGraphicsBeginImageContext(view.frame.size)
    sourceImage?.draw(at: CGPoint(x: 0, y: 275))
    let croppedImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    print("Partial ScreenShot")
    UIImageWriteToSavedPhotosAlbum(croppedImage!, nil, nil, nil)

swift 4

Answer 1

回答我自己的问题...

@IBAction func screenShot(_ sender: RoundButton) {
    sender.pulsate()
    makeSystemSound(sound: 1108)  // camera shutter
    //screenshot with cropping to CGRect from a view
    UIGraphicsBeginImageContext(view.frame.size)
    view.layer.render(in: UIGraphicsGetCurrentContext()!)
    let sourceImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    let captureFrame = view.convert(ResultsView.frame, from:self.view)
    let newImage = crop(image: sourceImage!, cropRect: captureFrame)
    print("Partial ScreenShot")
    UIImageWriteToSavedPhotosAlbum(newImage!, nil, nil, nil)
}

和函数:

func crop(image: UIImage, cropRect: CGRect) -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(cropRect.size, false, image.scale)
    let origin = CGPoint(x: cropRect.origin.x * CGFloat(-1), y: cropRect.origin.y * CGFloat(-1))
    image.draw(at: origin)
    let result = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext();
    return result
}