Krita UI, painting&sketching

[Ilmari Heikkinen]

Hi,

Bart Coppens asked me to post these to the mailing list as well, so here
goes.

This is a list of things that I noticed when drawing and playing around
with Krita a bit. It's mostly painting-centric, so focused on basic
drawing UI and doesn't say much about layers, selections, channels, etc.

I've been on the using end of image editing apps for around 9 years,
about three or four of those professionally (before going back to school
for comp sci.) The pro stuff was mostly GUI skins, nowadays I'm painting
and drawing for the hell of it. 

(My style of) painting usually stays under 20 layers, with normal layer
count of 1-5. Design jobs usually involve 10-50 layers and place focus
on layers, selections, masks, grouping, paths, guides, alignment and
text handling. GUI skins tend to be 50-150 layers with pretty much the
same focus as design, sans text, but with animations and button states
to deal with.

Maybe I'll try doing one of those too and write down the findings :)


I think these would help make Krita's UI more efficient for drawing and
painting.


Basic painting:

[ui issues]
- ctrl-+ & ctrl-- default zoom controls too far from usual hand   
  position. As replacement, z and shift-z would be one possibility. 

- no "press down - pan around"-key (e.g. MMB in GIMP)
  makes pan take more actions than optimal 
  ("drag with MMB" vs. "space down&up, LMB drag, space down&up.")

- tool shortcuts spread all over the keyboard (instead of being in the
  vicinity left hand home), makes head-up operation difficult (not
  looking at kb when changing tools and navigating the image)

- last used brush and blendmode not remembered on restart

- "Paint direct" somewhat confusing term, usually called "Incremental"

- can't do brush selection by "mouse down, move to brush, mouse up", 
  need to click outside to apply selection

- clear to bg color (backspace) doesn't work if there's no selection

[enhancements]
- default set of brushes doesn't go large enough (30, 60, 100, 150, 200,
  300 would be nice)

- selection of rectangular brushes and texture brushes lacking

- Tablet pressure curve control would be great (
  http://www.portalgraphics.net/en/images/pro-oc4-menu02-2.gif
  the curve control box in bottom right.)
  It is an editable curve that maps the pressure value read from the
  tablet (x-axis) to what is sent to the brush (y-axis.)
  E.g. hard pencil has pressure curve like _/ (have to press hard to
  make dark, easier to sketch), ink brush like /" (easy to make dark
  strokes.) Most useful as per-brush setting.
  
- Another nice thing would be the ability to constrain brush movement to
  cardinal directions / path / perspective guide by e.g. pressing down
  shift when drawing. Use case similar to using a ruler when drawing on
  paper.

- numbers controlling brush opacity would be nice too (1 = 10%, 2 =  
  20%, ...,  0 = 100%)

[bugs]
- brush outline is left behind if switching tools with keyboard 

- at high tablet pressure and pressure controlled size, the brush grows 
  larger than the brush bitmap, which leads to pixelation.



Layers:

- new layer button shows menu of adding different sorts of layers, but 
  layer palette has lots of free space. moving the buttons to the 
  palette would take one search+click away and make the UI more visible
  
- creating new layer shows a layer dialog, this is needed maybe 1% of 
  the time. Better just create a new layer directly and let user summon 
  dialog afterwards if needed
  ( hmm, seems like can't change colorspace of layer after creation? )

- can't lock alpha channel of layer from editing (which makes eraser on 
  bg layer a bit useless)

- Adding mask to layer doesn't make any visible change to GUI, causing
  confusion. Mask editing commands hidden in the "layer -> mask"-menu.
  Better solution would be to have mask visible in layers-palette a la
  GIMP, mask editing in layer context menu and "add layer mask"-button
  in layers-palette.


Random nits:

- zoom center not remembered after zooming out of image (zoom to some 
  place in a corner, zoom out to see whole image, wheel zoom back in)

- splitting the view very slow for some reason

- wheel zoom zooms towards image center, not cursor



HTH,
Ilmari