widget-vfuncs-class-init.h

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Authors:
 *   Daniel Boles <dboles.src+inkscape@gmail.com>
 *
 * Copyright (C) 2023 Daniel Boles
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#ifndef SEEN_UI_WIDGET_WIDGET_VFUNCS_CLASS_INIT_H
#define SEEN_UI_WIDGET_WIDGET_VFUNCS_CLASS_INIT_H
 
#include <optional>
#include <glibmm/extraclassinit.h>
#include <gtk/gtk.h>
#include <gtkmm/enums.h>
 
namespace Inkscape::UI::Widget {
 
class WidgetVfuncsClassInit : public Glib::ExtraClassInit {
public:
    struct CFuncs final {
        using CssChanged = void     (GtkWidget *, GtkCssStyleChange *);
        using Focus      = gboolean (GtkWidget *, GtkDirectionType   );
 
        CssChanged *css_changed = nullptr;
        Focus      *focus       = nullptr;
    };
 
protected:
    [[nodiscard]] WidgetVfuncsClassInit();
    ~WidgetVfuncsClassInit() override;
 
    virtual void css_changed(GtkCssStyleChange *change) {}
 
    virtual std::optional<bool> focus(Gtk::DirectionType direction) { return std::nullopt; }
 
private:
    // The following ‘thunk’ vfunc impls...
    static CFuncs::CssChanged _css_changed;
    static CFuncs::Focus      _focus      ;
    // ...are used by every instance of us.
    static constexpr CFuncs cfuncs = {
        &_css_changed,
        &_focus      ,
    };
};
 
} // namespace Inkscape::UI::Widget
 
#endif // SEEN_UI_WIDGET_WIDGET_VFUNCS_CLASS_INIT_H
 
/*
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  End:
*/
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