Get Image from CALayer or NSView (swift 3)

Question

I was looking for a way to render a CALayer or NSView and get NSImage back.

I have a custom class, which is a subclass of NSView. At the beginning I simply make a gra

Answer 1

Here are some NSView options:

extension NSView {

    /// Get `NSImage` representation of the view.
    ///
    /// - Returns: `NSImage` of view

    func image() -> NSImage {
        let imageRepresentation = bitmapImageRepForCachingDisplay(in: bounds)!
        cacheDisplay(in: bounds, to: imageRepresentation)
        return NSImage(cgImage: imageRepresentation.cgImage!, size: bounds.size)
    }

}

Or

extension NSView {

    /// Get `Data` representation of the view.
    ///
    /// - Parameters:
    ///   - fileType: The format of file. Defaults to PNG.
    ///   - properties: A dictionary that contains key-value pairs specifying image properties.
    /// - Returns: `Data` for image.

    func data(using fileType: NSBitmapImageFileType = .PNG, properties: [String : Any] = [:]) -> Data {
        let imageRepresentation = bitmapImageRepForCachingDisplay(in: bounds)!
        cacheDisplay(in: bounds, to: imageRepresentation)
        return imageRepresentation.representation(using: fileType, properties: properties)!
    }

}

---

Some CALayer options:

extension CALayer {

    /// Get `NSImage` representation of the layer.
    ///
    /// - Returns: `NSImage` of the layer.

    func image() -> NSImage {
        let width = Int(bounds.width * self.contentsScale)
        let height = Int(bounds.height * self.contentsScale)
        let imageRepresentation = NSBitmapImageRep(bitmapDataPlanes: nil, pixelsWide: width, pixelsHigh: height, bitsPerSample: 8, samplesPerPixel: 4, hasAlpha: true, isPlanar: false, colorSpaceName: NSDeviceRGBColorSpace, bytesPerRow: 0, bitsPerPixel: 0)!
        imageRepresentation.size = bounds.size

        let context = NSGraphicsContext(bitmapImageRep: imageRepresentation)!

        render(in: context.cgContext)

        return NSImage(cgImage: imageRepresentation.cgImage!, size: bounds.size)
    }

}

Or

extension CALayer {

    /// Get `Data` representation of the layer.
    ///
    /// - Parameters:
    ///   - fileType: The format of file. Defaults to PNG.
    ///   - properties: A dictionary that contains key-value pairs specifying image properties.
    ///
    /// - Returns: `Data` for image.

    func data(using fileType: NSBitmapImageFileType = .PNG, properties: [String : Any] = [:]) -> Data {
        let width = Int(bounds.width * self.contentsScale)
        let height = Int(bounds.height * self.contentsScale)
        let imageRepresentation = NSBitmapImageRep(bitmapDataPlanes: nil, pixelsWide: width, pixelsHigh: height, bitsPerSample: 8, samplesPerPixel: 4, hasAlpha: true, isPlanar: false, colorSpaceName: NSDeviceRGBColorSpace, bytesPerRow: 0, bitsPerPixel: 0)!
        imageRepresentation.size = bounds.size

        let context = NSGraphicsContext(bitmapImageRep: imageRepresentation)!

        render(in: context.cgContext)

        return imageRepresentation.representation(using: fileType, properties: properties)!
    }

}