Transparent themes without composition

[Aaron J. Seigo]

On Friday 01 May 2009, David Nolden wrote:
> When a theme designer makes a theme transparent, then he wants something to
> show through the theme. Without composition, the window manager will not
> supply that background, so in order to keep it looking similar to the way
> the designer has intended, plasma needs to paint a background behind the
> theme.

a solid colour based on some values provided by the system makes sense.

this is, essentially, no different than our "colorize to the system colour 
scheme" support.

> This already looks quite nice. But since many plasma themes have a glassy
> look, they highly profit from something more shining through them, since
> that's the only way they can retain that look. Transparency is not

and if you want that, use compositing. it's not a must-have feature and is 
exactly the kind of "well, we'll just cheat a bit when it's not compositing" 
feature i am so not favor of. it leads to:

* more configuration UI
* people using compositing asking for it
* more difficulty in q/a as we have more variables to test for and code around

the idea really is to degrade gracefully *from* compositing to non-
compositing, not to add features to non-compositing that aren't available in 
the compositing case.

non-composited desktop should look good and work well, but they are not the 
primary target. they are a supported secondary target.

because the next step along this path is "why don't we show window thumbnails 
using screen grabs in the tooltips when there is no compositing" and on and 
on. result? a bloated, horrible mess that has lots of sorta-kinda working 
features in the non-compositing case.

> In order to reach all this, I propose allowing the theme to paint behind
> floating parts:
> - A color given through the configuration file

the colour does not belong in the config file. it should come from the theme 
itself, allowing it to track the desktop colour scheme if that's how the theme 
is set up. this could be overridden by the active wallpaper for that 
screen/desktop, perhaps, so that wallpapers can say "here's a good matching 
colour".

this all belongs in PanelView.

> - A pattern given through the configuration file

no patterns.

> With the color thing implemented, adding support for a pattern is only a
> question of a few lines, and I cannot see a rational reason behind not
> allowing it when allowing the color.

because this will end up requiring configuration UI, is something that belongs 
in the theme itself and is YACP (yet another code path)

-- 
Aaron J. Seigo
humru othro a kohnu se
GPG Fingerprint: 8B8B 2209 0C6F 7C47 B1EA  EE75 D6B7 2EB1 A7F1 DB43

KDE core developer sponsored by Qt Software

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