Template Images

macOS can use an image as a template image, which means it automatically adapts to the control it is part of.

For this to work, an image has to be pure black/grayscale and transparent. On a dark control background, the image is automatically drawn white while on a light background it is drawn black.

This does not work inside of a paint event automatically. Instead, use the Template methods of the AppKitAddition to insert a picture as a template into the supported controls.