add initial (untested) implementation of canvas ruler item

1 files changed, 80 insertions, 0 deletions

diff --git a/libs/canvas/canvas/ruler.h b/libs/canvas/canvas/ruler.h
new file mode 100644
index 0000000000..ac72245c0f
--- /dev/null
+++ b/libs/canvas/canvas/ruler.h
@@ -0,0 +1,80 @@
+/*
+    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.
+*/
+
+#ifndef __CANVAS_RULER_H__
+#define __CANVAS_RULER_H__
+
+#include <string>
+#include <vector>
+
+#include "canvas/item.h"
+#include "canvas/fill.h"
+#include "canvas/outline.h"
+
+namespace ArdourCanvas
+{
+	
+class LIBCANVAS_API Ruler : virtual public Item, public Fill, public Outline
+{
+public:
+	struct Mark {
+		enum Style {
+			Major,
+			Minor,
+			Micro
+		};
+		std::string label;
+		double position;
+		Style  style;
+	};
+	
+	struct Metric {
+		Metric () : units_per_pixel (0) {}
+		virtual ~Metric() {}
+
+		double units_per_pixel;
+
+		/* lower and upper and sample positions, which are also canvas coordinates
+		 */
+		
+		virtual int get_marks (std::vector<Mark>&, double lower, double upper, int maxchars) const = 0;
+	};
+	
+	Ruler (Group *, const Metric& m);
+	
+	void set_range (double lower, double upper);
+	void set_size (Rect const&);
+
+	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;
+	void compute_bounding_box () const;
+	
+private:
+	const Metric& _metric;
+	Rect          _rect;
+
+	/* lower and upper and sample positions, which are also canvas coordinates
+	 */
+
+	Coord         _lower;
+	Coord         _upper;
+};
+
+}
+
+
+#endif