I experimented a bit with Hunspell, I think the hardest part is rendering the actual spelling mistakes (and displaying suggestions, assuming that those are wanted/needed). piet's text functionality doesn't seem to support anything useful in this regard (e.g. red "wavy" lines, or independently colored underlines).

very cool! regarding the text drawing capabilities: generally piet's API is limited, because it needs to find the common denominator for the different native backends.

I see a short term and a long term "fix" for it:

• short term: in the PenBehaviour trait, we currently pass in the piet_cairo CairoRenderContext for drawing. We could change it to a cairo context and could still draw with piet wherever we want by creating the piet context from it. We would need to test how well that works (especially if transformations and the save / restores are applied correctly and if the performance is good enough), but I believe I wrote something similar already in the top level render functions. When we have this we could use pango and its markup which seems to provide the features that you mentioned.

• long term: I have been watching piet-gpu, an emerging GPU / compute shader 2d renderer for a while now, and it is making rapid progress. The linebender community is writing this renderer for their own new gui toolkit xilem, and I believe they plan to provide a similarly capable (to pango) rich text API in it. It looks like this will still take some amount of time until it is usable, but when it is, I eventually want to replace the entire existing rendering in rnote-engine with this (and drop the gtk dependency), since I hope that this will be a lot faster and should also reduce memory usage. Then we could start using it to draw the typewriter and spellcheck too.

For schools that want to use this program in exams, there should be a way to disable Spellcheck and require an admin passwort to enable it again. (On windows, the installer could show an Option to not install dictonaries )
The user should be able to easily disable it as well.

I currently can use RNote in exams because it has no spellcheck. This should be possible after this feature gets added.

It was really hard for me to find modern MD editors with mathjax but without spellcheck that I can use in exams. This I a common problem these days

Hey there,

I would donate $100 if this issue were to be fixed. I use your app every day at school and would highly appreciate this feature, even if it is just highlighted in red text or underlined. For the dictionary, I would suggest the best way is to create a folder where the user can place their own dictionaries, like in Heiboard.

I don't really know how difficult it is in a complex application like Rnote, but I would love to see it.

Best regards,
develcooking