NSImage class extension method for resizing NSImages to specific pixel dimensions instead of points.

Resize NSImage to Pixel Dimensions.swift

public extension NSImage {
    /// Resizes the image to the specified pixel dimensions.
    /// - Parameter newSize: The width and height (in pixels) to resize the image to.
    func resize(to newSize: NSSize) -> NSImage {
        guard let rep = NSBitmapImageRep(bitmapDataPlanes: nil, pixelsWide: Int(newSize.width), pixelsHigh: Int(newSize.height), bitsPerSample: 8, samplesPerPixel: 4, hasAlpha: true, isPlanar: false, colorSpaceName: .calibratedRGB, bytesPerRow: 0, bitsPerPixel: 0) else {
            assertionFailure("Could not create NSBitmapImageRep")
            return self
        }
        rep.size = newSize
        
        NSGraphicsContext.saveGraphicsState()
        NSGraphicsContext.current = NSGraphicsContext(bitmapImageRep: rep)
        let rect = NSRect(origin: .zero, size: newSize)
        self.draw(in: rect, from: .zero, operation: .copy, fraction: 1.0)
        NSGraphicsContext.restoreGraphicsState()
        
        let resizedImage = NSImage(size: newSize)
        resizedImage.addRepresentation(rep)
        return resizedImage
    }
}