- frame.
  - ("simulates" a finite canvas; infinite canvas alone is awful for artists)
  - visual only (do strokes outside anyway, might enlarge later)
  - enable/disable/move/resize

- add a preferences dialog
  - set maximum brush radius
  - set canvas memory limit
  - set canvas border outside visible window (in percent)
  - set "reallocate how much in advance" maybe?
  - zoom quality
  - remember window pos or not

- dedicated "slow random" input
  - or just "random slowness"?
    - could lead to unwanted correlations

- canvas rotation
  - (fast rotozoom? also would be nice to use OpenGL if available)

- allow dots drawing
  - a dot should draw even without motion
  - is dabs-per-second enough, or is dabs-per-dpressure needed?

- pen/eraser
  - recognize tool and asociate brush and color, as brushkeys do
  - default to a white sharp ink tip on the eraser

- focus on ink a bit more

- try to get the smear brush described by simastrick

- tilt support 
  - what can tilt be used for?
  - I need (someone with) a tilt tablet to test it

- show brush radius
  - "some symbol to see the current size of the painting-tool"
  - (mouse cursor shape, like in the GIMP? A key to show/hide it?
    - a key to quickly blink the shape? hmm...
    - note: shape size changes quickly!

? zoom-out only for viewing somehow?
  - do not resize canvas when zooming, only when moving?
  - better do it right: do not allocate memory for white canvas areas.

- edit global pressure nonlinearity curve
  - maybe wacom tool? maybe for each brush?

- more brush information
  - attach text notes to brush
  - attach a small demo-replay / demo image
  - brush categories - put all inky brushes into subfolder etc.

- copy/paste buttons curve shapes 
  - buttons next to shape? shared "symlinked" shape?
  - the "custom" input partially solves this problem now.

- change brush without changin radius?
  - how? distinguish brush tip vs brush size vs brush dynamics?

- allow non-circle brush shapes

- button for fast GIMP in- and export, also a GIMP plugin if needed

- maybe avoid gaps when using the "offset by speed"
  - and add a setting to intentionally do such gaps

- layers.
  - alpha support (for both rendering and brush strokes)
  - new infinite surface class
  - rewrite the rendering code
  - layer dialog (select / set occupancy)