Color Picker Blending Feature: Advice Needed!

[Boudewijn Rempt]

Note: the patch was posted here:

https://phabricator.kde.org/D11895


On maandag 2 april 2018 13:44:59 CEST David Revoy wrote:
> Hi Emmet,
> Interesting and as you already mentioned ; even more interesting if the
> tool-options of the dedicated color-picker tool could affect the one used
> while painting with the brush tool ( or with the fill tool, or other
> drawing tools) using the <ctrl> key shortcut. -David​​
> 
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> 
> On April 1, 2018 1:18 PM, Boudewijn Rempt <boud at valdyas.org> wrote:
> > ​​
> > 
> > That does sound interesting :-). It would most convenient if you could
> > post
> > 
> > the patch on phabricator.kde.org so everyone can take a look and play with
> > it!> 
> > On zondag 1 april 2018 01:54:41 CEST Emmet O'Neill wrote:
> > > Hi there, Krita community! I'm Emmet and I've been working on a small
> > > Krita
> > > 
> > > feature patch together with my brother Eoin (pronounced Owen).
> > > 
> > > Essentially, we've come up with (and mostly implemented) a new feature
> > > for
> > > 
> > > Krita's color picker that allows for mixing the newly picked color with
> > > the
> > > 
> > > current color of the user's bush.
> > > 
> > > This is a relatively small and simple change that we think makes a
> > > massive
> > > 
> > > difference when it comes to painting and color mixing workflow, as it
> > > 
> > > significantly reduces the need for on-canvas color blending techniques
> > > that
> > > 
> > > have been the standard for digital painters.
> > > 
> > > A great analogy and part of the inspiration for this idea is traditional
> > > 
> > > painting, especially water-based painting. In watercolor or gouache, for
> > > 
> > > example, if you dip your brush into a red puddle and then a blue puddle,
> > > 
> > > your brush stroke will be some shade of purple on the page - the colors
> > > mix
> > > 
> > > in the brush. The same thing happens to some degree in most forms of
> > > 
> > > painting, and controlling this is a powerful tool for the traditional
> > > 
> > > painter. So, what we're working on is a feature that adds configurable
> > > 
> > > "blending" to Krita's color picker: when "blending" is set to full the
> > > 
> > > color picker works as it always has by replacing your previous brush
> > > color
> > > 
> > > with the newly picked color. However, when blending is set to a lower
> > > value
> > > 
> > > (~1-99%) your previous brush color is partially mixed with the newly
> > > picked
> > > 
> > > color, with each separate click of the color picker mixing in a little
> > > bit
> > > 
> > > more. Obviously I'm a bit biased, but I think mixing colors this way
> > > feels
> > > 
> > > amazing and very intuitive, much like dipping a brush into paint!
> > > 
> > > As of right now, we have this feature working while using the dedicated
> > > 
> > > color picker tool (kis_tool_colorpicker) and we've added a small slider
> > > to
> > > 
> > > control the blending amount to the color picker gui (wdgcolorpicker.ui).
> > > 
> > > But color picker blending currently isn't working when using the
> > > "global"
> > > 
> > > color picker that pops up when you press 'ctrl' while another tool is
> > > 
> > > selected. This is where we're hoping that somebody who is more familiar
> > > 
> > > with the Krita codebase can provide some advice with how to proceed! I
> > > 
> > > think we've tracked down the relevant code for the 'ctrl-picker' over in
> > > 
> > > "kis_tool_utils" and "kis_color_picker_stroke_strategy", and while the
> > > code
> > > 
> > > is pretty similar to the other dedicated color picker code, we've run
> > > into
> > > 
> > > an issue: in "kis_tool_colorpicker.cc" we were able to easily get the
> > > 
> > > previous brush color by calling
> > > 
> > > "canvas()->resourceManager()->foregroundColor()" before mixing it with
> > > the
> > > 
> > > picked color, but we're not sure how to access the foreground color from
> > > 
> > > within "kis_color_picker_stroke_strategy.cc". Does anybody have any idea
> > > 
> > > about the proper way of getting access to foregroundColor() from within
> > > the
> > > 
> > > color picker stroke strategy code or alternatively passing it into that
> > > 
> > > code at some other point?
> > > 
> > > It probably goes without saying that we're both new to the Krita
> > > codebase
> > > 
> > > and contributing to open source projects in general! We'll gladly accept
> > > 
> > > any guidance or suggestions, and if anybody wants to try out "color
> > > picker
> > > 
> > > blending" for themselves I'd be happy to try to send a little patch over
> > > so
> > > 
> > > you can see what we have so far.
> > > 
> > > Thanks, Emmet.
> > 
> > --
> > 
> > Boudewijn Rempt | https://www.valdyas.org | https://www.krita.org


-- 
Boudewijn Rempt | https://www.valdyas.org | https://www.krita.org
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