[WIDGET] Shader Canvas

[mantacid]

Description of the widget

This widget would allow GLSL to be rendered to the widget. This could be combined with EWW's existing systems and user-made scripts to make reactive displays that can't be otherwise achieved.
I'd also recommend implementing a uniform that allows the set wallpaper to be passed in as a sampler2D, so that the state of the system can apply post-processing effects to the wallpaper.

Implementation proposal

The Gsk.GLShader widget could work perfectly for this. Additionally, if the eww implementation could grab the rendered state of inline yuck, it could inject itself into the rendering process and allow for post-processing effects on other widgets.

Example usage

• using a script to get data from the system audio, one can make reactive audio visualizers on their desktop.
• Overlaying invisible EWW ui elements over a shader representation of them could allow for some really interesting animation effects.
• weather widgets that display conditions as an animated scene.
• edge outlines that change color depending on mouse location.

Additional context

No response