Icons installed by apps

[Albert Astals Cid]

El Dimecres, 23 de setembre de 2015, a les 22:12:39, Jaroslaw Staniek va 
escriure:
> On 23 September 2015 at 09:31, Harald Sitter <sitter at kde.org> wrote:
> >> You mean if {appname} and {appname}-foo doesn't right?
> >> 
> >> the XDG icon spec has some kind of inheritance built into the name so
> >> 
> >> someaction.png
> >> 
> >> is chosen if you don't have
> >> 
> >> someaction-veryspecific.png
> >> 
> >> So you may want to use another way of prefixing that doesn't mess with
> >> that
> >> like and _ or just nothing at all.
> > 
> > I seem to recall this actually coming up in Randa. IIRC the icon theme
> > artists would very much prefer if custom icons you want to provide are
> > using the specification system outlined by the theme spec and are
> > installed to hicolor. Which then behaves exactly as Albert outlined,
> > when QIcon resolves for "icon-specific-very" the following order
> > applies:
> > 
> > icon.png < icon-specific.png < icon-specific-very.png
> > 
> > So you could have places/database-implode-kexi.png which makes the
> > icon you installed themable as database-implode.png, but at the same
> > time makes it non-conflicting with other applications that may want to
> > install database-implode to hicolor.
> > 
> > On a related note, since it came up in the original mail: yes, breeze
> > is a default fallback in kf5 applications *as long as the
> > frameworkintegration platformtheme is installed and loaded* [1].
> > Additionally breeze currently inherits from oxygen, through the theme
> > config itself, this might go away at some point though. So right now
> > the effective resolution order is userTheme > breeze > (oxygen) >
> > hicolor.
> 
> Thanks for this info Harald and Albert!
> 
> Some background about motivation.
> My idea is to default to breeze on non-Plasma platform and on without
> the frameworkintegration platformtheme.
> And avoid surprising on Windows and Mac. Silently hoping that some
> reasonable habits could help to convince someone to use KF5 for
> general cross platform apps developments.
> 
> Related thing: I don't expect new app-specific icons/emblems will be
> prepared for oxygen or various themes.
> Surely it's better for _truly_ 3rd-party plugins (that I expect to
> appear more one day) to know the theme recommendations and defaults --
> I see consistency as more valuable than freedom of theming for complex
> apps.
> For some time I was also wondering that documentation's screenshots
> have to pick one theme anyway, so better not to confuse users...
> 
> Another thing: should I wonder that in my strace logs, for icons that
> exist for hicolor only, the "userTheme > breeze > (oxygen) > hicolor"
> scheme results in 4 * 'dozens of lookups'? Because of the fallback
> strategies this cannot be cached I guess, only actual content is
> cached. A simple filesystem stat() may be cheap but there are lots of
> it. For example a custom file that sits in hicolor only when I have
> breeze theme selected calls stat() 515 times. (there's no the
> 'userTheme' step). To get just a simple and single 4KiB icon, n*515
> memory (re)allocations are needed.

Yes, see the "QIcon::fromTheme(xxx, someFallback)" thread in kde-frameworks-
devel

> 
> As I mentioned in this thread quite a few KDE apps use .qrc for custom
> icons but no idea if this intentional or rather a convenient approach
> well supported by Qt Designer and .ui files.

Do they? I've never seen any :D

> Thirdly, I suppose it's possible to indicate in the code that I am
> looking for a "place" icon group for example. That would slash the
> number of lookups and also limit conflicts. Maybe that would be a
> violation of behaviour required by fd.o? No idea.
> 
> My fresh test results in one observation, network-server-database-kexi
> which causes the above 515 stat()'s
> sits in share/icons/hicolor/22x22/places/network-server-database-kexi.svg.
> It is not found, instead
> share/icons/breeze/places/22/network-server-database.svg is returned.
> This is maybe because network-server-database is a prefix equal to an
> existing icon? Why is it of higher priority than the exact match?

You mean that breeze/network-server-database.svg is picked over 
hicolor/network-server-database-kexi.svg when requesting network-server-
database-kexi ?

I don't know enough about the icon theme spec to answer that, you'd have to 
read it and see if it's a bug on QIcon (i remember seeing some merge requests 
that were never finished about something similar) or the intented behaviour.

Cheers,
  Albert

> No change after removing of the icon cache. To make sure what happens
> I'd try to use '_' separators as Albert suggests.
> 
> I appreciate any comments.
> 
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