Migrated here from Gna! bug 19906, a wish for 'Line Pressure Preset' to ease setting of the auto-pressure applied when drawing lines, curves, polygons, ellipses and circles.
On my previous proposition mockup, I was still assuming the final user knew how to use a graph/curve to set pressure but then 2 year has passed and I realised "our userbase consists mostly of artists, not sandal-wearing UNIX mystics" .
So, here is an updated mockup where the 'graph/curve' could be fold/unfold for custom fine tuning, and line pressure presets show large thumbnails/buttons with a limited set of 4 presets:
Looks like a great idea - I love the presets notion, and it's clear to me how they'd translate to points.
By the way, ee have the beginnings of code in MyPaint for rendering nice smooth fully interpolated brushstokes between any set of random points now -- whether it's for previews or directly onto the canvas. Check out the brush auto-preview button in the brush icon editor. As of now it's lurking in gui/drawutils.py. This could be expanded to do these previews and more, but it probably needs to be made more efficient and more general.
Other options we may want to think of:
In the middle-distance future, I want to add an inking tool which uses stroke data capture in a different way: #13. There's a lot that could be shared with this code.
I think this bug is a post-1.2 enhancement - it's a bit too much work even as just an adjunct to the pressure curve for us to cram it in before 1.2. Hope that's OK.
(patches and pull requests welcome though, if anyone wants to pick it up)
Oh sure, it's definitely a post 1.2 enhancement. No hurry at all, I migrated this item only today for cleaning reasons.
Good job for the 'auto' thumbnail editing. It looks good. Good to know the thumbnails can be generated now. Maybe this cool system could be extended later to allow user to 'add his custom pressure curve' to the preset list, or remove it.
From my point of view, I don't think the capture of a pressure profile box is necessary. Custom graph/curve makes better/smoother/purer/predictable results.
I also like how the config options appears on the 'Tool Option' docker since GTK3 ; only when key is pressed while drawing freehand, and how the line update real-time on canvas when graph is changed. I was a bit confused at first to see the option blink and it took me time to realise I had to hold continuously , even over the 'Tool Option' docker to access to the graph , but now it's ok ; I get it.