fitted_canvas_widget.h

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/*
    Copyright (C) 2021 Paul Davis
    Author: Ben Loftis <ben@harrisonconsoles.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
 
#ifndef _gtk_ardour_fitted_canvas_widget_h_
#define _gtk_ardour_fitted_canvas_widget_h_
 
#include <canvas/canvas.h>
 
#include <gtkmm/layout.h>
 
/* FittedCanvasWidget has these properties:
 *  it is provided a 'nominal size' on construction, which it will request of gtk
 *  if asked, will resize itself when the user gui/font scale changes
 *  it 'fits' the Item that was first attached to Root  (presumably the top-level widget or container)
 *    the fitted Item will be explicitly resized to fit when the canvas size is allocated
 *    the fitted Item may be a container; it should allocate child positions during size_allocate()
 */
class FittedCanvasWidget : public ArdourCanvas::GtkCanvas
{
public:
        /* per gtk convention you may use -1 for width OR height if you don't care about that dimension */
        FittedCanvasWidget (float nominal_width, float nominal_height, bool follow_scale = true);
 
        /* call if the root item's first child is changed, to force a size-allocate on it */
        void repeat_size_allocation ();
 
        /* always returns the nominal size, regardless of children */
        void on_size_request (Gtk::Requisition*);
 
        void on_size_allocate (Gtk::Allocation&);
 
        virtual float nominal_width() {return _nominal_width;}
        virtual float nominal_height() {return _nominal_height;}
 
private:
        ArdourCanvas::Rect _allocation;
 
        float _nominal_width;
        float _nominal_height;
        bool  _follow_scale;
};
 
#endif // _gtk_ardour_fitted_canvas_widget_h_