Stacked canvases

[nickbetteridge]

Is one able to create a window containing stacked canvases? It looks as though only one canvas can be projected on an open window. If this is the case, would it be possible to add this feature? I have a number of use-cases where the different canvas layers are used as overlays.

[ddeclerck]

Hi,
The library was indeed designed that way. I'll see what can be done about adding this feature, though be aware that it requires quite a bit of refactoring in the code and might not be available soon.
As an alternative, you can use offscreen canvases and blit them over an onscreen canvas (though that's probably less efficient).

[nickbetteridge]

Thanks for getting back. Yes, having a z-plane is definitely a requirement for building image editors, vlsi custom layout editors, diagram editors with drag-and-drop, griding, flashing error layers etc. Once a tree becomes reasonably large and there's a fair amount of activity happening on the overlays, doing off-screen copying will end up being noticeably slow. A z-plane is a must-have.