maxy my good fellow, you rock!
Works great!... except...
I tried making my own pencil brush, binding opacity to speed by setting the "opaque multiply" base value to 1 and its Fine speed value to -1. This gives strokes that nicely adapt to speed - but the spook lines between strokes are back
Moreover when, with this brush, I move the cursor over the canvas with the USB mouse rather than using the touchscreen, a line is drawn wherever the cursor goes, even while not holding the left mouse button (when I do hold the LMB the line gets more opaque; both with and without LMB opacity depends on speed).
The problem does not occur when I bind radius or hardness to speed. So that gives almost the desired effect of stroke 'impact' being inversely proportional to speed; but it would be nice to be able to fine-tune it so radius, hardness and
opacity all adapt to speed. This leads to:
It escapes my understanding why you would want to use MyPaint on a device that does not report pressure levels
If you saw a great scene, and you had only a biro, rather than great arts materials, would you refuse to draw?
Pressure sensitivity is the real deal. But given that I'm carrying my UMPC with me all the time, and that I have no inclination to add some more weight and lose some funds by adding a tablet - it's a delight to be able to whip up MyPaint. I had ArtRage in Windows (am now on Mint) and did a couple e-paintings which people seemed to like.
With acrylic paint style stuff in particular pressure is not that much of an issue, as you do light bits by using white paint anyway, not by applying less.
However for pencil style brushes some 'natural' variation in stroke impact is nice. Hence my trying to tie opacity to speed. Even with only radius and hardness tied to it, I think the effect looks pretty nice and 'alive'.
It may be a bit of a niche but I imagine there'd be quite a few users of mobile devices with simple touchscreens that will appreciate what can be done with the right software.
Finally, having explored MyPaint a bit more now - the brush options, canvas rotation, backgrounds, the elegant shortcut assignment... I'm in total awe.