cairo sub-surface prototype - intermediate flattened group renderer.

libs/canvas/canvas/surface_group.h

@@ -0,0 +1,48 @@
+/*
+    Copyright (C) 2011-2013 Paul Davis
+    Author: Robin Gareus <robin@gareus.org>
+
+    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_SURFACE_GROUP_H__
+#define __CANVAS_SURFACE_GROUP_H__
+
+#include <list>
+#include <vector>
+
+#include "canvas/visibility.h"
+#include "canvas/group.h"
+
+namespace ArdourCanvas {
+
+class LIBCANVAS_API SurfaceGroup : public Group
+{
+public:
+	explicit SurfaceGroup (Group *);
+	explicit SurfaceGroup (Group *, Duple);
+	~SurfaceGroup ();
+
+	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
+
+private:
+	mutable Duple _surface_position;
+	mutable Duple _surface_geometry;
+	mutable Cairo::RefPtr<Cairo::ImageSurface> _surface;
+};
+
+}
+
+#endif

libs/canvas/surface_group.cc

@@ -0,0 +1,114 @@
+/*
+    Copyright (C) 2011-2013 Paul Davis
+    Author: Robin Gareus <robin@gareus.org>
+
+    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 "canvas/surface_group.h"
+
+using namespace std;
+using namespace ArdourCanvas;
+
+SurfaceGroup::SurfaceGroup (Group* parent)
+	: Group (parent)
+	, _surface_position (0,0)
+	, _surface_geometry (0,0)
+	, _surface (0)
+{
+
+}
+
+SurfaceGroup::SurfaceGroup (Group* parent, Duple position)
+	: Group (parent, position)
+	, _surface_geometry (0,0)
+	, _surface (0)
+{
+
+}
+
+SurfaceGroup::~SurfaceGroup ()
+{
+
+}
+
+void
+SurfaceGroup::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	bool re_expose = false;
+	boost::optional<Rect> bb = bounding_box ();
+
+	if (bb) {
+		Duple geo = Duple (bb->width (), bb->height ());
+		if (geo != _surface_geometry) {
+			re_expose = true;
+#if 0 // DEBUG
+			printf ("re allocate surface group %1.f x %.1f @ %1.f x %.1f self: %1.f x %.1f\n",
+					geo.x, geo.y, bb->x0, bb->y0, _position.x, _position.y);
+#endif
+			if (geo.x > 32768 || geo.y > 32768) {
+				// TODO allocate N surfaces, render at offset and stitch them together.
+				// OR use one surfacen and re-expose child items when offset changes
+				return;
+			}
+
+			_surface = Cairo::ImageSurface::create (Cairo::FORMAT_ARGB32, geo.x, geo.y);
+			_surface_geometry = geo;
+			_surface_position = Duple (bb->x0, bb->y0);
+		}
+	}
+
+	if (!_surface) return;
+
+	Rect a (0, 0, _surface_geometry.x, _surface_geometry.y);
+
+	if (!re_expose) {
+		Duple tmp_p0 = window_to_item (Duple (area.x0, area.y0));
+		Duple tmp_p1 = window_to_item (Duple (area.x1, area.y1));
+		Rect wa (tmp_p0.x, tmp_p0.y, tmp_p1.x, tmp_p1.y);
+		boost::optional<Rect> d = a.intersection (wa);
+		assert (d);
+		a = d.get ();
+	}
+
+	Duple window_space;
+	window_space = item_to_window (Duple (_position.x + _surface_position.x, _position.y + _surface_position.y));
+	Cairo::RefPtr<Cairo::Context> cr = Cairo::Context::create (_surface);
+
+#if 1 // clear surface, needed if any content is semi-transparent
+	cr->save ();
+	cr->set_operator (Cairo::OPERATOR_CLEAR);
+	cr->rectangle (a.x0, a.y0, a.x1, a.y1);
+	cr->fill ();
+	cr->restore ();
+#endif
+
+#if 0 // DEBUG
+	printf ("EXPOSE: %1.f x %.1f -> %1.f x %.1f\n", a.x0, a.y0, a.x1, a.y1);
+	Rect dbg = item_to_window (a);
+	printf ("RENDER: %1.f x %.1f -> %1.f x %.1f  WS: %1.f x %.1f \n",
+			dbg.x0, dbg.y0, dbg.x1, dbg.y1, window_space.x, -window_space.y);
+#endif
+
+	cr->translate (-window_space.x, -window_space.y);
+
+	Group::render (item_to_window (a), cr);
+
+	context->set_source (_surface, window_space.x, window_space.y);
+	context->paint ();
+}

libs/canvas/wscript

@@ -51,6 +51,7 @@ canvas_sources = [
         'rectangle.cc',
         'root_group.cc',
         'stateful_image.cc',
+        'surface_group.cc',
         'text.cc',
         'types.cc',
         'utils.cc',