Function updateButtonForWidget

kdevplatform/sublime/idealbuttonbarwidget.cpp:118–146

    }

    void updateButtonForWidget()
    {
        Q_ASSERT(m_button);

        // Use the inactive color for the text of the tool button if its tool view widget is disabled
        // in order to indicate whether the tool view is enabled even while it is hidden.

        const auto enabled = toolViewWidget()->isEnabled();
        if (enabled && !m_wasToolViewWidgetEverDisabled) {
            // Most tool view widgets are never disabled. So this is a fast path:
            // keep the default (enabled) button text color, nothing to do.
            return;
        }

        if (!m_wasToolViewWidgetEverDisabled) {
            Q_ASSERT(!enabled); // otherwise should have returned earlier
            m_wasToolViewWidgetEverDisabled = true;
            // Once the palette of the button is adjusted, we have to handle its palette-change events because the text
            // color of the button is no longer updated automatically when the user switches between color schemes.
            m_button->installEventFilter(this);
        }

        auto palette = m_button->palette();
        // Replacing the specialized color role QPalette::ButtonText has no effect
        // for some reason, so replace the more general role QPalette::WindowText instead.
        KColorScheme::adjustForeground(palette, enabled ? KColorScheme::NormalText : KColorScheme::InactiveText,
                                       QPalette::WindowText, KColorScheme::Button);
        m_button->setPalette(palette);
    }

    IdealDockWidget* const m_dock;
    IdealToolButton* m_button = nullptr;