Function setUpFallbackIconPaths

src/shared/shared.cpp:1312–1344

}

void setUpFallbackIconPaths(QWidget* parent) {
    /**
     * Qt 5.12 adds a feature to add fallback paths for icons. This is a very simple way to automatically load custom
     * icons when the icon theme doesn't provide a suitable alternative.
     * However, we need to support a much older Qt version. Therefore we cannot use this very very handy feature.
     * We basically iterate over all buttons which carry an icon and (re)load it, but this time provide a fallback
     * loaded from our private data directory.
     */

    // for now we only support buttons
    // we could always add more widgets which provide an icon property
    const auto buttons = parent->findChildren<QAbstractButton*>();

    for (const auto& button : buttons) {
        const auto iconName = button->icon().name();

        // sort out buttons without an icon
        if (iconName.length() <= 0)
            continue;

        // load icon from theme, providing the bundled icon as a fallback
        // loading an "empty" (i.e., isNull() returns true) icon as fallback, as returned by loadIconWithFallback(...),
        // works just fine
        auto fallbackIcon = loadIconWithFallback(iconName);
        auto newIcon = QIcon::fromTheme(iconName, fallbackIcon);

        if (newIcon.isNull() || newIcon.pixmap(16, 16).isNull())
            newIcon = fallbackIcon;

        // now replace the button's actual icon with the fallback-enabled one
        button->setIcon(newIcon);
    }
}