add set_scroll_thickness to provide a way to "zoom" the scrollbar

Change-Id: I551112fb097a6ac2b442cd37d1a16bd2b34ecc54
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/137932
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/include/svtools/scrolladaptor.hxx b/include/svtools/scrolladaptor.hxx
index f6a2cef..d321091 100644
--- a/include/svtools/scrolladaptor.hxx
+++ b/include/svtools/scrolladaptor.hxx
@@ -68,6 +68,8 @@ public:

    bool HasGrab() const { return m_xScrollBar->has_grab(); }

    void SetThickness(int nThickness);

    ScrollAdaptor(vcl::Window* pParent, bool bHori);
    virtual void dispose() override;
};
diff --git a/include/vcl/weld.hxx b/include/vcl/weld.hxx
index c886ba2..1ffa2d8 100644
--- a/include/vcl/weld.hxx
+++ b/include/vcl/weld.hxx
@@ -2517,6 +2517,9 @@ public:
    virtual int adjustment_get_lower() const = 0;
    virtual void adjustment_set_lower(int upper) = 0;

    virtual int get_scroll_thickness() const = 0;
    virtual void set_scroll_thickness(int nThickness) = 0;

    virtual ScrollType get_scroll_type() const = 0;

    void connect_adjustment_changed(const Link<Scrollbar&, void>& rLink) { m_aChangeHdl = rLink; }
diff --git a/svtools/source/control/scrolladaptor.cxx b/svtools/source/control/scrolladaptor.cxx
index d6805f2..14480f0 100644
--- a/svtools/source/control/scrolladaptor.cxx
+++ b/svtools/source/control/scrolladaptor.cxx
@@ -114,4 +114,6 @@ tools::Long ScrollAdaptor::DoScroll(tools::Long nNewPos)
    return m_xScrollBar->adjustment_get_value() - nOrig;
}

void ScrollAdaptor::SetThickness(int nThickness) { m_xScrollBar->set_scroll_thickness(nThickness); }

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/source/app/salvtables.cxx b/vcl/source/app/salvtables.cxx
index 02394ac..673c2ea 100644
--- a/vcl/source/app/salvtables.cxx
+++ b/vcl/source/app/salvtables.cxx
@@ -2554,6 +2554,21 @@ public:
    }

    virtual ScrollType get_scroll_type() const override { return m_xScrollBar->GetType(); }

    virtual int get_scroll_thickness() const override
    {
        if (m_xScrollBar->GetStyle() & WB_HORZ)
            return m_xScrollBar->get_preferred_size().Height();
        return m_xScrollBar->get_preferred_size().Width();
    }

    virtual void set_scroll_thickness(int nThickness) override
    {
        if (m_xScrollBar->GetStyle() & WB_HORZ)
            m_xScrollBar->set_height_request(nThickness);
        else
            m_xScrollBar->set_width_request(nThickness);
    }
};
}

diff --git a/vcl/unx/gtk3/gtkinst.cxx b/vcl/unx/gtk3/gtkinst.cxx
index 158bc84..cd26d1f 100644
--- a/vcl/unx/gtk3/gtkinst.cxx
+++ b/vcl/unx/gtk3/gtkinst.cxx
@@ -8411,6 +8411,7 @@ class GtkInstanceScrollbar final : public GtkInstanceWidget, public virtual weld
private:
    GtkScrollbar* m_pScrollbar;
    GtkAdjustment* m_pAdjustment;
    GtkCssProvider* m_pThicknessCssProvider;
    gulong m_nAdjustChangedSignalId;

    static void signalAdjustValueChanged(GtkAdjustment*, gpointer widget)
@@ -8456,6 +8457,7 @@ public:
#else
        , m_pAdjustment(gtk_range_get_adjustment(GTK_RANGE(m_pScrollbar)))
#endif
        , m_pThicknessCssProvider(nullptr)
        , m_nAdjustChangedSignalId(g_signal_connect(m_pAdjustment, "value-changed", G_CALLBACK(signalAdjustValueChanged), this))
    {
#if GTK_CHECK_VERSION(4, 0, 0)
@@ -8560,9 +8562,45 @@ public:
        return ScrollType::Drag;
    }

    virtual int get_scroll_thickness() const override
    {
        if (gtk_orientable_get_orientation(GTK_ORIENTABLE(m_pScrollbar)) == GTK_ORIENTATION_HORIZONTAL)
            return gtk_widget_get_allocated_height(GTK_WIDGET(m_pScrollbar));
        return gtk_widget_get_allocated_width(GTK_WIDGET(m_pScrollbar));
    }

    virtual void set_scroll_thickness(int nThickness) override
    {
        GtkStyleContext *pStyleContext = gtk_widget_get_style_context(GTK_WIDGET(m_pScrollbar));

        if (m_pThicknessCssProvider)
        {
            gtk_style_context_remove_provider(pStyleContext, GTK_STYLE_PROVIDER(m_pThicknessCssProvider));
            m_pThicknessCssProvider = nullptr;
        }

        m_pThicknessCssProvider = gtk_css_provider_new();
        int nSlider = nThickness > 6 ? nThickness - 6 : 1;
        const OString sData = "slider { min-height: " + OString::number(nSlider) + "px;"
                                      " min-width: " + OString::number(nSlider) + "px; }";
        css_provider_load_from_data(m_pThicknessCssProvider, sData.getStr(), sData.getLength());
        gtk_style_context_add_provider(pStyleContext, GTK_STYLE_PROVIDER(m_pThicknessCssProvider),
                                       GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);

        if (gtk_orientable_get_orientation(GTK_ORIENTABLE(m_pScrollbar)) == GTK_ORIENTATION_HORIZONTAL)
            gtk_widget_set_size_request(GTK_WIDGET(m_pScrollbar), -1, nThickness);
        else
            gtk_widget_set_size_request(GTK_WIDGET(m_pScrollbar), nThickness, -1);
    }

    virtual ~GtkInstanceScrollbar() override
    {
        g_signal_handler_disconnect(m_pAdjustment, m_nAdjustChangedSignalId);
        if (m_pThicknessCssProvider)
        {
            GtkStyleContext *pStyleContext = gtk_widget_get_style_context(GTK_WIDGET(m_pScrollbar));
            gtk_style_context_remove_provider(pStyleContext, GTK_STYLE_PROVIDER(m_pThicknessCssProvider));
        }
    }
};