22 White on Black Panel Predicate

package: gui-lib

procedure
(white-on-black-panel-scheme?) → boolean?

This predicate is intended to determine if the underlying operating system is in a dark mode.

Under relatively recent versions of Mac OS, it queries dark mode directly. See also application-dark-mode-handler.

On other platforms, it determines if the foreground color of the panel background is lighter than the background color. If they appear to be the same, white-on-black-panel-scheme? returns #f.

1	Aligned Pasteboard
2	Arrow Toggle Snip
3	Bitmap Label
4	Cache-image Snip
5	Close Icon
6	Expandable Snip
7	GIF and Animated GIF Writing
8	Graphs
9	Hierarchical List Control
10	Include Bitmap
11	Interactive Value Port
12	Name Message
13	Path Dialog
14	Plot
15	Switchable Button
16	Image Core
17	Matrix Snip
18	Snip Canvases
19	Syntax Browser
20	Te X Table
21	Terminal Window
22	White on Black Panel Predicate
23	Acknowledgments
	Index