more icon theme stuff (blah)

[Brian J. Tarricone]

Jasper Huijsmans wrote:

> Brian J. Tarricone wrote:
>
>> ok...  so now my icons are totally screwed up (or rather, they were, 
>> until i hacked my system to pieces fixing it).  i _really_ think all 
>> icons need to be moved to $datadir/icons pronto.  i also think all 
>> our themes need to be prefixed with "Xfce-".  things just aren't 
>> working right with $datadir/xfce4/icons, and i can't seem to figure 
>> out why.
>>
>> it _seems_ obvious.  i point at an icon, "gnome-settings", to act as 
>> the icon for the "Settings" menu.  it doesn't show up.  i move aside 
>> $datadir/xfce4/icons/gnome, and presto, it appears.  i move our gnome 
>> theme back, and it's gone again.  but look!  gnome-multimedia isn't.  
>> and i have no idea why it shows up, when gnome-settings doesn't.
>>
>> the gnome-settings problem seems to indicate that GtkIconTheme is 
>> giving up if it finds a theme dir, but can't find an icon (regardless 
>> if there is another identical theme directory farther down in the 
>> search path).  honestly, i think this is a gtk bug, but the bug i 
>> filed on gnome bugzilla over 2 weeks(?) ago hasn't even been 
>> commented upon.  i really don't want to fork GtkIconTheme.  i really 
>> don't.  i don't have the time or energy to maintain it, to say 
>> nothing of familiarising myself with it.
>>
>> so i say the hell with it, let's just move everything to 
>> $datadir/icons.  that seems to be the Right Thing to do anyway.  the 
>> cool thing is that, e.g., the "Xfce-Noia" theme can "inherit" from 
>> "Noia", so it will pick up icons from the latter theme if they aren't 
>> in ours.
>>
>> the only downside (aside from the time and work required to do the 
>> change) is that of handling fallback behaviour.  if the user selects 
>> a non-"Xfce-" theme, they may not have the files the panel requires.  
>> the simple fix for that is to duplicate the icons from our default 
>> ("Xfce-Curve") theme and dump them in $datadir/icons/hicolor.  so 
>> maybe we overwrite someone else's icons.  tough.  that's a packaging 
>> issue.
>>
>> the fix for this downside, however, has its own downside.  that means 
>> that no matter what non-"Xfce-" theme the user picks, they'll have to 
>> live with "Xfce-Curve" icons for the panel.  the panel _could_ have 
>> an "icon theme override" option, but that sounds rather hackish.  i 
>> can't see any way around this.
>>
>> thoughts?
>>
>
> AFAIK, the way the icon theme spec was intended, applications install 
> default icons in the hicolor theme. (Question: how does this work when 
> installing in a different prefix? Should we install our own 
> index.theme file?).

as for how the icon theme spec is written, you're supposed to look in 
$XDG_DATA_DIRS/icons, which should default to $datadir/icons if it isn't 
explicitly set.  GtkIconTheme is a little bit sloppy there.  it ignores 
the XDG_DATA_DIRS env var, but it searches in $datadir/icons and 
/usr/share/icons (regardless of prefix).  this bothers me somewhat, but 
i didn't get around to fixing this in time for gtk 2.4.0, so...

> Icon themes are installed to some known locations and can provide 
> alternative icons. Idealy, I guess, icon themes are installed as one 
> package. If we want to provide our own icons for existing icon themes 
> we could try getting them into the official theme or make our theme 
> package depend on the presence of the original theme.

getting stuff into the official theme takes time and effort, and i'm not 
sure anyone really wants to do that =p.  also, there are lots of 
official themes out there, all with different authors.  and, iirc, the 
official themes aren't really all that consistent as to what they 
contain (beyond a few common ones, i think).

> Using xfce-<name> themes inheriting from the original <name> theme 
> would work but doesn't really feel right to me.

i know.  it doesn't feel right to me either =(.

> On a related note, how does gnome make sure it's gnome theme is used 
> as default fallback? Or doesn't it?

i dunno; i think olivier already answered this.

> Another thing I'm unsure about is the interaction between gtk themes 
> and icon themes. Several gtk themes specify an icon theme; will our 
> settings dialog always override this, or should we set the icon theme 
> to 'None' and make sure the theme set by the gtkrc file is used? Would 
> this work at all?

ugh, i forgot about that.  totally and completely.  right now it ignores 
the gtk theme's icon theme preference, but it shouldn't be too painful 
to add support for that.  i think a simple policy is fine:
- by default, use whatever we've designated as the default icon theme
- if a gtk theme is selected which supplies and icon theme name, first 
check to see if it exists (maybe checking first to see if an Xfce-$name 
theme exists, if we go that route), and set it if it does.  if not, 
leave it as it is.
- if the user later selects a gtk theme that doesn't have an associated 
icon theme, leave the icon theme setting as it was before the gtk theme 
selection was made.

>     Jasper

    -brian