initial implementation of a more specialized canvas item for (sustained) notes

libs/canvas/canvas/note.h

@@ -0,0 +1,44 @@
+/*
+    Copyright (C) 2018 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_NOTE_H__
+#define __CANVAS_NOTE_H__
+
+#include "canvas/visibility.h"
+#include "canvas/rectangle.h"
+
+namespace ArdourCanvas
+{
+
+class LIBCANVAS_API Note : public Rectangle
+{
+public:
+	Note (Canvas*);
+	Note (Item*);
+
+	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
+	void set_velocity (double fract);
+
+  private:
+	static bool _show_velocity_bars;
+	double _velocity;
+};
+
+}
+
+#endif /* __CANVAS_NOTE_H__ */

libs/canvas/note.cc

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+/*
+    Copyright (C) 2018 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 <cairomm/context.h>
+
+#include "gtkmm2ext/colors.h"
+
+#include "canvas/note.h"
+#include "canvas/debug.h"
+
+using namespace std;
+using namespace ArdourCanvas;
+
+bool Note::_show_velocity_bars = true;
+
+Note::Note (Canvas* c)
+	: Rectangle (c)
+	, _velocity (0.5)
+{
+}
+
+Note::Note (Item* parent)
+	: Rectangle (parent)
+	, _velocity (0.5)
+{
+}
+
+void
+Note::set_velocity (double fract)
+{
+	_velocity = max (0.0, min (1.0, fract));
+	redraw ();
+}
+
+void
+Note::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	Rectangle::render (area, context);
+
+	if (_show_velocity_bars && _velocity > 0.0) {
+
+		Rect self (item_to_window (Rectangle::get().translate (_position), false));
+
+		if ((self.y1 - self.y0) < 5) {
+			/* not tall enough to show a velocity bar */
+			return;
+		}
+
+		/* 2 pixel margin above and below
+		   outline_width() margin on left
+		   set width based on velocity
+		*/
+
+		self.y0  = self.y0 + 2;
+		self.y1  = self.y1 - 2;
+		const double width = (self.x1 - self.x0) - (2 * outline_width());
+		self.x0  = self.x0 + outline_width();
+		self.x1  = self.x0 + (width * _velocity);
+
+		const Rect draw = self.intersection (area);
+
+		if (!draw) {
+			return;
+		}
+
+		Gtkmm2ext::set_source_rgba (context, Gtkmm2ext::contrasting_text_color (fill_color()));
+		context->rectangle (draw.x0, draw.y0, draw.width(), draw.height());
+		context->fill ();
+	}
+}