cocoa: how to render view to image?

user_1664669 0
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I want to know is there any method to render a view to image? just like a screenshot, but I can specify any view to that method. I know how to do it in ios. Saving view content, but how can I do it in mac os ?

macos cocoa
3 Answers

The answer from @Remizorr works in ObjectiveC like explained even under macOS High Sierra 10.13.4. - Xcode 9.2.

It also works for layerBacked view (wantsLayer = true).

Here is the updated Swift version :

extension NSView {

func snapshotImage() -> NSImage? {

    guard let window = window,
        let screen = window.screen,
        let contentView = window.contentView else { return nil }

    let originRect = self.convert(self.bounds, to:contentView)
    var rect = originRect
    rect.origin.x += window.frame.origin.x
    rect.origin.y = 0
    rect.origin.y += screen.frame.size.height - window.frame.origin.y - window.frame.size.height
    rect.origin.y += window.frame.size.height - originRect.origin.y - originRect.size.height
    guard window.windowNumber > 0 else { return nil }
    guard let cgImage = CGWindowListCreateImage(rect, .optionIncludingWindow, CGWindowID(window.windowNumber), CGWindowImageOption.bestResolution) else { return nil }

    return NSImage(cgImage: cgImage, size: self.bounds.size)
}

}

NOTE: This works even for a WKWebView and it does take a snapshot of a WKWebView video playing (which WKWebViews takeSnapshot does not) ;).

user_68523130
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