basic, initial structure for canvas widget item

libs/canvas/canvas/widget.h

@@ -0,0 +1,50 @@
+/*
+    Copyright (C) 2011-2013 Paul Davis
+    Author: Carl Hetherington <cth@carlh.net>
+
+    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 __CANVAS_WIDGET_H__
+#define __CANVAS_WIDGET_H__
+
+#include "canvas/visibility.h"
+#include "canvas/item.h"
+
+#include "gtkmm2ext/cairo_widget.h"
+
+namespace ArdourCanvas
+{
+
+class LIBCANVAS_API Widget : virtual public Item
+{
+public:
+	Widget (Group *, CairoWidget&);
+	
+	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
+	void compute_bounding_box () const;
+
+	CairoWidget const & get () const {
+		return _widget;
+	}
+
+private:
+	CairoWidget& _widget;
+	bool event_proxy (GdkEvent*);
+};
+
+}
+
+#endif

libs/canvas/widget.cc

@@ -0,0 +1,105 @@
+/*
+    Copyright (C) 2014 Paul Davis
+
+    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.
+*/
+
+#include <iostream>
+#include <cairomm/context.h>
+#include "pbd/stacktrace.h"
+#include "pbd/compose.h"
+
+#include "canvas/canvas.h"
+#include "canvas/widget.h"
+#include "canvas/debug.h"
+#include "canvas/utils.h"
+
+using namespace std;
+using namespace ArdourCanvas;
+
+Widget::Widget (Group* parent, CairoWidget& w)
+	: Item (parent)
+	, _widget (w)
+{
+	Event.connect (sigc::mem_fun (*this, &Widget::event_proxy));
+}
+
+bool
+Widget::event_proxy (GdkEvent* ev)
+{
+	return _widget.event (ev);
+}
+
+void
+Widget::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	std::cerr << "Render widget\n";
+
+	if (!_bounding_box) {
+		std::cerr << "no bbox\n";
+		return;
+	}
+
+	Rect self = item_to_window (_bounding_box.get());
+	boost::optional<Rect> r = self.intersection (area);
+
+	if (!r) {
+		std::cerr << "no intersection\n";
+		return;
+	}
+
+	Rect draw = r.get ();
+	cairo_rectangle_t crect;
+	crect.x = draw.x0;
+	crect.y = draw.y0;
+	crect.height = draw.height();
+	crect.width = draw.width();
+
+	std::cerr << "will draw " << draw << "\n";
+	context->save ();
+	context->translate (-draw.x0, -draw.y0);
+	//context->rectangle (draw.x0, draw.y0, draw.width(), draw.height());
+	// context->clip ();
+
+	_widget.render (context->cobj(), &crect);
+
+	context->restore ();
+}
+
+void
+Widget::compute_bounding_box () const
+{
+	std::cerr << "cbbox for widget\n";
+
+	GtkRequisition req;
+	Gtk::Allocation alloc;
+
+	_widget.size_request (req);
+
+	std::cerr << "widget wants " << req.width << " x " << req.height << "\n";
+
+	_bounding_box = Rect (0, 0, req.width, req.height);
+
+	/* make sure the widget knows that it got what it asked for */
+	alloc.set_x (0);
+	alloc.set_y (0);
+	alloc.set_width (req.width);
+	alloc.set_height (req.height);
+
+	_widget.size_allocate (alloc);
+
+	_bounding_box_dirty = false;
+}
+

libs/canvas/wscript

@@ -56,6 +56,7 @@ canvas_sources = [
         'types.cc',
         'utils.cc',
         'wave_view.cc',
+        'widget.cc',
         'xfade_curve.cc',
 ]