RCC for icons - update: Re: Icons installed by apps

[Jaroslaw Staniek]

On 18 February 2016 at 18:25, Kåre Särs <kare.sars at iki.fi> wrote:

> On Thursday, February 18, 2016 02:51:58 PM René J.V. Bertin wrote:
> > On Thursday February 18 2016 13:55:18 Jaroslaw Staniek wrote:
> > >>> > since QIcon::fromTheme() apaprently isn't able to find app icons.
> >
> > Care to explain? QIcon::fromTheme() doesn't find anything "out of the
> box"
> > on OS X (and I presume on MS Windows), but that is only because no theme
> > search path is set on those platforms. When you add the standard XDG icon
> > repository to the icon search path on OS X, even "pure" Qt5 application
> > will start showing icons all over if you have an icon theme installed --
> > including in widgets that should not have icons according to the HIG.
> Also
> > on OS X, fromTheme() will only return the application icon (as in the
> icon
> > shown in the Finder) if the current theme defines that same icon for the
> > calling application, and the theme search path is set of course. In all
> > other cases it will not, because the application icon is not defined
> > through a theme on OS X (nor is it on MS Windows, I presume).
> > >> I think the solution with a packaged breeze icons resource working
> > >> out-of-the box could be a good (lightweight) addition for non-Plasma
> > >> (non-Linux?) users of KF5, to popularize KF5. They grab the icons
> package
> >
> > Popularise, with Breeze "art"work? O:-)
> > Anyway,  I don't think "grabbing an icon package" will work on OS X, not
> if
> > you want to create standalone app bundles which by definition contain
> > everything they need.
> > >> and icons just work without thousands of files, caching, etc. 'One in
> a
> > >> million' would of these users would be interested in theming.
> >
> > I'd up that estimate if we're still talking about Breeze icons here O:-)
> >
> > >> PS2: I have been beaten by situations such as KToolBar setting 0-size
> > >> icons by default.
> >
> > Partly this is because almost no KF5 code uses the fallback argument of
> > QIcon::fromTheme() explicitly, which means that the function returns an
> > empty icon if the search fails. In particular, statements like
> >
> > app->setWindowIcon(QIcon::fromTheme(programName))
> >
> > should read
> >
> > app->setWindowIcon(QIcon::fromTheme(programName, app->windowIcon()))
> >
> > >> This is in a Windows env where no themes are (properly) installed. If
> the
> > >> rcc-based solution is in use I would imagine that ideally all the KF5
> > >> code
> > >> detects this somehow and would not look for xdg standard themes
> through
> > >> the
> > >> classic KIconLoader but silently adapt so the rcc resource works
> great.
> > >> Just a dream.
> >
> > If your rcc resource corresponds to the resource mentioned in the
> > QIcon::fromTheme() documentation (I think that talks about "qrc") and if
> I
> > interpret that documentation correctly then yes, code using that function
> > will find icons from the rcc/qrc "builtin" resource over those in xdg
> > themes (if the XDG icon repository is even in the icon theme search
> path).
> > >>> What I don't know however is whether artists consider that these
> icons
> > >>> should be themeable...
> >
> > I think icon artists will consider that you should touch their icons (for
> > theming or anything else). They will probably also consider that their
> > icons are the "best" but they really should also consider it a right for
> > anyone to use other icons ;)
> >
>
> The breeze.rcc file way is actually how Christoph solved it in Kate for
> Windows and OSX. We create an .rcc file from the breeze icons and at
> start-up
> we search for the file in QStandardPaths::DataLocation and if the file is
> found we load it with  registerResource() and add ":/icons" to the
> themeSearchPaths. (kate.git/icons.h)
>
> Christoph also added ":/icons" to the search path in kicontheme so that
> xmlgui
> toolbars and friends also get the icons from the .rcc file.
>
> We get all the same icons as on Linux neatly in one file :)
>

​Thanks, it works on Windows (no platform theme).
​​How to make it work on Linux too (KF5 5.19.0, Qt 5.5.1), i.e. I'd like to
have only used icons from the .rcc regardless of availability of
FrameworkIntegrationPlugin.so KDEPlatformTheme.so?
​
We're talking about this code:​

​https://quickgit.kde.org/?p=kate.git&a=blob&f=icons.h​​​

As soon as QResource::registerResource("breeze.rcc") is called, ":/icons"
is
​appended to the theme search path (checked using
QIcon::themeSearchPaths()).

There's a line QIcon::setThemeSearchPaths(QStringList() <<
QStringLiteral(":/icons")).

- When I have this line enabled and I have no FrameworkIntegrationPlugin.so
& KDEPlatformTheme.so installed, no icons are available at all

- When I have this line disabled, breeze XDG theme is used but kexi icons
(from the .rcc file are missing), regardless of availability of
FrameworkIntegrationPlugin.so & KDEPlatformTheme.so.


​For the record, Qt 5.5's code is:​

​QIcon QIcon::fromTheme(const QString &name, const QIcon &fallback)
{
    QIcon icon;

    if (qtIconCache()->contains(name)) {
        icon = *qtIconCache()->object(name);
    } else {
        QPlatformTheme * const platformTheme =
QGuiApplicationPrivate::platformTheme();
        bool hasUserTheme = QIconLoader::instance()->hasUserTheme();
        QIconEngine * const engine = (platformTheme && !hasUserTheme) ?
platformTheme->createIconEngine(name)
                                                   : new
QIconLoaderEngine(name);
        QIcon *cachedIcon  = new QIcon(engine);
        icon = *cachedIcon;
        qtIconCache()->insert(name, cachedIcon);
    }

    // Note the qapp check is to allow lazy loading of static icons
    // Supporting fallbacks will not work for this case.
    if (qApp && icon.availableSizes().isEmpty())
        return fallback;

    return icon;
}
​

-- 
regards, Jaroslaw Staniek

KDE:
: A world-wide network of software engineers, artists, writers, translators
: and facilitators committed to Free Software development - http://kde.org
Calligra Suite:
: A graphic art and office suite - http://calligra.org
Kexi:
: A visual database apps builder - http://calligra.org/kexi
Qt Certified Specialist:
: http://www.linkedin.com/in/jstaniek
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