Tempo ramps - add Canvas::FramedCurve and use it in the tempo marker bar.

libs/canvas/canvas/framed_curve.h

@@ -0,0 +1,66 @@
+/*
+    Copyright (C) 2013 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_FRAMED_CURVE_H__
+#define __CANVAS_FRAMED_CURVE_H__
+
+#include "canvas/visibility.h"
+
+#include "canvas/interpolated_curve.h"
+#include "canvas/poly_item.h"
+#include "canvas/fill.h"
+
+/* similar to a Curve, with the first point being a height definition rather than a point to
+   interpolate.
+*/
+
+namespace ArdourCanvas {
+
+class LIBCANVAS_API FramedCurve : public PolyItem, public InterpolatedCurve
+{
+  public:
+    FramedCurve (Canvas*);
+    FramedCurve (Item*);
+
+    enum CurveFill {
+	    None,
+	    Inside,
+	    Outside,
+    };
+
+    void compute_bounding_box () const;
+    void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;
+    void set (Points const &);
+
+    void set_points_per_segment (uint32_t n);
+
+    bool covers (Duple const &) const;
+    void set_fill_mode (CurveFill cf) { curve_fill = cf; }
+
+  private:
+    Points samples;
+    Points::size_type n_samples;
+    uint32_t points_per_segment;
+    CurveFill curve_fill;
+
+    void interpolate ();
+};
+
+}
+
+#endif