Because Canvas objects guarantee that rendering commands issued to them will be represented until the Canvas is dropped on the floor and garbage collected, they need to maintain some sort of permanent history of the results of that rendering. Currently that is a pixel store.

In order to be able to manage those resources more effectively, we need to have a mechanism that is cooperative with the application so that they can restore the contents of a Canvas if we find need to release its pixel store.

This mechanism could be any of:

- An observable property that indicates when the pixels were destroyed.

- An event that can be handled and the painting reissued.

- A paint/update mechanism similar to Swing/AWT, but more limited in scope (it would just deal with repaints).