SUMMARY

Flatpak KCM can not find a bunch of icons for the apps, in particular: Telegram Desktop, LocalSend, LibreOffice, Kdenlive and Shotcut. The `FlatpakHelper::iconSourceUrl` algorithm[1] goes an extra mile only to fail to locate the proper icons which were specified in the exported desktop entries the whole time!

Take a look at **LocalSend** for example:

```
$ cd /var/lib/flatpak/app/org.localsend.localsend_app/x86_64/stable/306064fe957c0bc287c6353de49295eb5302335bcecd527f08e8a73f249e454a

$ tree export
export
├── bin
│   └── org.localsend.localsend_app
└── share
    ├── applications
    │   └── org.localsend.localsend_app.desktop
    ├── icons
    │   └── hicolor
    │       ├── 32x32
    │       │   └── apps
    │       │       └── org.localsend.localsend_app-tray.png
    │       └── 512x512
    │           └── apps
    │               └── org.localsend.localsend_app.png
    └── metainfo
        └── org.localsend.localsend_app.metainfo.xml

$ cat export/share/applications/org.localsend.localsend_app.desktop

[Desktop Entry]
[...]
Name=LocalSend
Exec=/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=localsend --file-forwarding org.localsend.localsend_app @@u %U @@
Icon=org.localsend.localsend_app
X-Flatpak=org.localsend.localsend_app
```

the algorithm has no idea about "512x512" directory, it just take some random `nextDir = dir.entryList().at(0);` which on my machine consistently ends up being "32x32" — the one which contains tray icon instead of the app icon.

Let's take **Shotcut** for example. Things are even funnier there: for some reason it provides exported *scalable* icons of Glaxnimate:

```
files/share/icons
└── hicolor
    ├── 128x128
    │   └── apps
    │       └── org.shotcut.Shotcut.png
    ├── 512x512
    │   └── apps
    │       ├── glaxnimate.png
    │       └── org.mattbas.Glaxnimate.png
    ├── 64x64
    │   └── apps
    │       └── org.shotcut.Shotcut.png
    └── scalable
        └── apps
            ├── glaxnimate.svg
            └── org.mattbas.Glaxnimate.svg
```

So the algorithm falls for `if (dir.exists(QStringLiteral("scalable")))` despite the Shotcut icon not being there.


**Telegram** exports Icon=org.telegram.desktop, but provides a symbolic version with a "-symbolic" suffix which hides it from the algorithm while masking other directories than "hicolor/symbolic".

**Kdenlive** provides its scalable icon with *.svgz extension which the algorithm doesn't account for.

And finally, **LibreOffice** isn't exactly a single app: it is a bundle of apps, with a central .desktop launcher named simply org.libreoffice.LibreOffice.desktop; however its Icon= is not as simple — it has a suffix which algorithm has no idea about: "org.libreoffice.LibreOffice.startcenter.png".

STEPS TO REPRODUCE
1. Install some flatpak apps, including the aforementioned ones.
2. Add some debug logs to the iconSourceUrl function.
3. Open Flatpak KCM

OBSERVED RESULT
Some apps are missing their icons, replaced with a generic one instead.

EXPECTED RESULT
Reuse the wheel instead of reinventing it.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2
Kernel Version: 6.13.6-arch1-1 (64-bit)
Graphics Platform: X11


ADDITIONAL INFORMATION

[1] The `FlatpakHelper::iconSourceUrl` algorithm:

```
QUrl iconSourceUrl(const QString &displayName, const QString &flatpakName, const QString &appBaseDirectory)
{
    QString dirPath = appBaseDirectory + QStringLiteral("/files/share/icons/hicolor/");
    QDir dir(dirPath);
    dir.setFilter(QDir::NoDotAndDotDot | QDir::AllDirs);

    QString nextDir;
    if (dir.exists(QStringLiteral("scalable"))) {
        nextDir = QStringLiteral("scalable");
    } else if (dir.exists(QStringLiteral("symbolic"))) {
        nextDir = QStringLiteral("symbolic");
    } else if (!dir.isEmpty()) {
        nextDir = dir.entryList().at(0);
    } else {
        return QUrl();
    }
    dir.cd(nextDir + QStringLiteral("/apps"));

    QString file = flatpakName + QStringLiteral(".png");
    if (!dir.exists(file)) {
        file = flatpakName + QStringLiteral(".svg");
        if (!dir.exists(file)) {
            file = displayName.toLower() + QStringLiteral(".png");
            if (!dir.exists(file)) {
                file = displayName.toLower() + QStringLiteral(".svg");
                if (!dir.exists(file)) {
                    return QUrl();
                }
            }
        }
    }
    return QUrl::fromLocalFile(dir.absoluteFilePath(file));
}
```