I believe there is a real use case for darker or lighter themes, but this
particular theme is not particularly maintained and has no light variant (or to
be accurate: the light variant is just a link to the "Default" one). If someone
is interested in such themes, we'll welcome contributions to revive a new theme
which should have at the very least both a light and dark version, and we could
name it "Contrast" (rather than "Darker" which focuses on a dark variant only).
I think it's better to do it this way rather than releasing with a half-done
job.
The Compact theme code is nearly the same as the Default one, apart from setting
palette icon size to small (which is already something done by the "Override
icon sizes" setting in Preferences), setting font-size to small (which can be
independently set by our "Font Scaling" setting) and setting 3 paddings.
Rather than having this separate theme, it feels like just moving the padding
changes as part of the icon size makes sense. In particular since, when setting
icons to "Small" right now, the default padding really feels a bit huge and out
of place. So all-in-one seems a better choice.
At first, I wanted to set a padding proportional to the icon size, but it didn't
work well. For now, I'll just choose padding sizes manually.
Until now, we were following a similar concept of color schemes as what most OS
are doing. For instance, Freedesktop recently introduced a tri-state color
scheme of "Prefer Light", "Prefer Dark" and "Default", the latter being either
whatever the software prefers (e.g. we prefer either Dark or Gray for graphics
software usually) or what the system prefers. See #8675.
Until now, with GTK, we only had a boolean "prefer dark" setting through the
"gtk-application-prefer-dark-theme" settings. There is not even a "prefer
light".
Nevertheless for graphics application, there is clearly a third case (fourth if
we added a "follow system color preferences" which we don't implement for now):
gray mode and in particular middle gray. Having a middle gray UI is often
considered a necessity when working on colors in order to protect our perception
of color from being influenced by surrounding UI.
To fill this need, we were proposing a Default vs. a Gray theme in GIMP, but
this was a bit confusing and felt illogical, as discussed on IRC some time ago.
Also depending on whether you chose "prefer dark" or not for the gray theme,
this one was itself 2 themes, which made things odd and harder to work on.
Instead this commit:
- adds a color scheme concept in GIMP with 3 variants so far: light, gray and
dark. A possible fourth (future) variant might be to follow the system
preference (do all OS provide such a queriable option?).
- Our Gray theme is merged into Default (as the gray color scheme variant).
- Custom themes can add the following CSS files: gimp-light.css, gimp-gray.css,
gimp-dark.css which are the base file for their respective scheme. gimp.css is
still used as a fallback though it is not necessary (our own Default theme
does not provide a gimp.css anymore). Custom themes don't have to provide all
3 variants. A theme can just provide one or 2 variants if it only wants to
support 1 or 2 use cases.
The Default theme may have been a bit too dark. Instead let's have it a
tiny bit lighter (and also foreground color a bit less white).
For now, the old "Default" dark theme doesn't disappear totally and is
moved to a "Darker" theme as we have been discussing and wondering on
whether this is prefered by some people (it is). Aryeom also thought a
darker theme may be a good idea.
Moreover Liam actually thought that losing some of the contrast
(especially with the text a tiny bit less white now) is not desired in
his case where eyes may not be as sharp as they used to. Therefore a
"High Contrast" theme may be needed.
Aryeom also suggested that sliders to choose colors could be a much more
generic solution, which might be possible yet would require more ugly
hacks generating on-the-fly theme changes (we do something similar for
dark theme choice already).
This is all work-in-progress and a result from Wilber Week 2023 work.
So what we read on the topic is to use (as base color) the gray which is
perceptually half-way between black and white. Unfortunately it can mean
different colors. For instance if using the sRGB TRC, the #808080 color is
sometimes cited.
Instead I went with the color LCH (50, 0, 0), i.e. with half perceptual
lightness in "CIE LCH(ab) float" babl space, i.e. #777777 in sRGB. It
corresponds to the 18.42% gray which is often refered to, so it seemed a fine
choice.
This replaces proposal in !683 because the contributor is not responding
anymore, and also it uses the common theme base CSS files used by all other
official themes.
Something which is regularly asked is to use smaller icons. We used to
have a "Small" theme in 2.8, which got away in 2.10 with icon sizing (cf
issue #6121).
This is a revival of such a theme (except I call it "Compact" because it
feels more appropriate than "Small"). The theme is basically the same as
"Default" (through an include), just tweaking some size related CSS
rules.
… variant.
Now with my recent code, instead of creating 2 different themes, I make
it a single theme containing both a Light and Dark variant.
I move all semantic logic into common.css which will be included by both
variants after they set up their color definitions.
For choosing the basic gray to use for the dark variant, I first looked
up what is usually recommended. Most articles on the web about dark
themes would cite some "Material design" project (apparently originated
from Google) which makes guidelines for Android/iOS/Flutter and web
applications. Their guidelines recommend #121212 ("Dark Grey") as
background color. I tried, it's **really** dark. Maybe I'm just not used
to it, but it feels like it might be OK for small phone "apps" which
people might want to watch in the dark, but possibly not for a full
grown desktop software. I don't really know, I might be wrong and some
people might want to edit their pictures with such dark GUI.
Anyway for now, I settled for a base background #303030, which is
already quite dark, darker than Adwaita dark or than our 2.10 dark
variant, but at least doesn't feel like a black hole.
Jehan