Show HN: Scrawl-canvas filter functionality demo

The Scrawl-canvas library's filters functionality is inspired by SVG filters. Filter operations can be ordered in ways to combine different sets of operations to achieve complex effects.

The library comes with an extensive set of pre-built filters, including: color and alpha channel manipulations; matrix, pixellate, blur; compositing and blending operations; palette reduction and dithering; image and noise asset upload (for use with composites and blends); gradient, and displacement, mapping.

Filters can be applied to individual graphical objects, to Groups of such objects, and also to Cell displays.

Additional links:

- A gallery of SC compound filter effects - https://scrawl-v8.rikweb.org.uk/demo/filters-103.html

- SC stencil (background) filter functionality - https://scrawl-v8.rikweb.org.uk/demo/filters-028.html