Drawing app is very laggy on decent hardware

[Netherquark]

Use case

I just use drawing to doodle/note down formulae while im studying and its surprisingly laggy for that use case. I use an AMD 2200G based system with 8GB of ram, utilising the integrated graphics, which is more than enough for a simple Paint-equivalent I'd reckon. I think the problem is probably related to hardware acceleration, or rather, a lack thereof.
I'm finding that as I use the pen/cil utility, the drawing lags behind and when I undo/redo, it lags for a solid 5 seconds or so before becoming functional again.

Suggested solution

I think working on hardware acceleration would help a lot.

[maoschanz]

as I use the pen/cil utility, the drawing lags behind

this is a problem related to the size of the canvas, and it will be improved with version 1.0.0, i suppose luxurious hardware is correlated with bigger displays so the issue is worse than with a normal older laptop

It could probably benefit from hardware acceleration but i've no idea if it's feasible before switching to GTK4

meanwhile you can use a smaller canvas and zoom in it, i suppose it would work better

when I undo/redo, it lags for a solid 5 seconds or so before becoming functional again.

this one is trickier because it's caused by the architecture of the history. Basically, an "undo" recomputes everything you did (except the undone operation) since the last time you saved the picture. If you don't save often, or use tools that require more complex computation (blurring, selection, etc.), it may take a lot of time

The app could "remember" more frequently the entire picture so there would be less to compute, but then it would use more RAM

[Netherquark]

excited for V1 then!

I think for the latter, it might be a good idea to allow that in settings. Up to you though. It'll be a pretty bit of coding on your end.

[earboxer]

Basically, an "undo" recomputes everything you did (except the undone operation) since the last time you saved the picture. If you don't save often, or use tools that require more complex computation (blurring, selection, etc.), it may take a lot of time

The app could "remember" more frequently the entire picture so there would be less to compute, but then it would use more RAM

What if it just "remembered" 1 previous state, so a single undo/redo would perform well (Most drawing apps I know work this way, instead of allowing infinite undos)

[maoschanz]

it just moves the problem away of 1 step so idk if it would really fix anything

even if many simple drawing apps don't do that, the current design isn't an alien abomination, it's a basic implementation of non-linear editing, which is a cool feature: aside of the memory-efficient "infinite" history, it allows workflows like "undo several steps > add operations to the graph > redo the steps" for example. No user knows that detail i guess, but anyways it's cool. And the plan was that this history will also help to fix #123:

Although this process is more computationally intensive than directly modifying the original content, changing the edits themselves can be almost instantaneous

anyways i'm not the first one to implement this idea in an image editor, there are probably some design patterns out there to do it with lighter computation, maybe even examples, what's needed here is some plagi... some well-sourced research among other free software.

[maoschanz]

(closed because it's a duplicate of #200 and #168)