To change image, drag-and-drop an image file over the canvas
Select filter
Entity
Composite
Alpha
To note: Javascript is not running in this browser environment. The canvas element is ignored; instead a placeholder image displays where the canvas would have appeared.
Test purpose
Create a test Picture entity
Create a Cog entity
Create a variety of filters to apply to the Cog entity, using it as a stencil so the area behind the wheel displays with the filter applied to it