new TrackingText canvas item, to resolve conceptual issues with the Editor::VerboseCursor

libs/canvas/canvas/tracking_text.h

@@ -0,0 +1,49 @@
+/*
+    Copyright (C) 2011-2013 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 __ardour_canvas_tracking_text_h__
+#define __ardour_canvas_tracking_text_h__
+
+#include <string>
+#include "canvas/text.h"
+
+namespace ArdourCanvas {
+
+class LIBCANVAS_API TrackingText : public Text
+{
+  public:
+	TrackingText (Canvas*);
+	TrackingText (Item*);
+	
+	void show_and_track (bool track_x, bool track_y);
+	void set_offset (Duple const &);
+	void set_x_offset (double);
+	void set_y_offset (double);
+
+  private:
+	bool track_x;
+	bool track_y;
+	Duple offset;
+
+	void pointer_motion (Duple const&);
+	void init ();
+};
+
+}
+
+#endif /* __ardour_canvas_tracking_text_h__ */

libs/canvas/tracking_text.cc

@@ -0,0 +1,143 @@
+/*
+    Copyright (C) 2011-2013 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.
+*/
+
+#include <algorithm>
+
+#include "canvas/canvas.h"
+#include "canvas/tracking_text.h"
+
+using namespace ArdourCanvas;
+
+TrackingText::TrackingText (Canvas* c)
+	: Text (c)
+	, track_x (true)
+	, track_y (true)
+	, offset (Duple (10, 10))
+{
+	init ();
+}
+
+TrackingText::TrackingText (Item* p)
+	: Text (p)
+	, track_x (true)
+	, track_y (true)
+	, offset (Duple (10, 10))
+{
+	init ();
+}
+
+void
+TrackingText::init ()
+{
+	_canvas->MouseMotion.connect (sigc::mem_fun (*this, &TrackingText::pointer_motion));
+	set_ignore_events (true);
+	hide ();
+}
+
+void
+TrackingText::pointer_motion (Duple const & winpos)
+{
+	if (!_visible) {
+		return;
+	}
+
+	Duple pos (_parent->window_to_item (winpos));
+
+	if (!track_x) {
+		pos.x = position().x;
+	}
+
+	if (!track_y) {
+		pos.y = position().y;
+	}
+
+	pos = pos.translate (offset);
+
+	/* keep inside the window */
+	
+	Rect r (0, 0, _canvas->width(), _canvas->height());
+
+	/* border of 200 pixels on the right, and 50 on all other sides */
+
+	const double border = 50.0;
+
+	r.x0 += border;
+	r.x1 = std::max (r.x0, (r.x1 - 200.0));
+	r.y0 += border;
+	r.y1 = std::max (r.y0, (r.y1 - border));
+
+	/* clamp */
+	
+	if (pos.x < r.x0) {
+		pos.x = r.x0;
+	} else if (pos.x > r.x1) {
+		pos.x = r.x1;
+	}
+
+	if (pos.y < r.y0) {
+		pos.y = r.y0;
+	} else if (pos.y > r.y1) {
+		pos.y = r.y1;
+	}
+
+	/* move */
+
+	set_position (pos);
+}
+
+void
+TrackingText::show_and_track (bool tx, bool ty)
+{
+	track_x = tx;
+	track_y = ty;
+
+	bool was_visible = _visible;
+	show ();
+
+	if (!was_visible) {
+		/* move to current pointer location. do this after show() so that
+		 * _visible is true, and thus ::pointer_motion() will do 
+		 * something.
+		 */
+		Duple winpos;
+
+		if (!_canvas->get_mouse_position (winpos)) {
+			return;
+		}
+
+		pointer_motion (winpos);
+	}
+}
+
+void
+TrackingText::set_x_offset (double o)
+{
+	offset.x = o;
+}
+
+void
+TrackingText::set_y_offset (double o)
+{
+	offset.y = o;
+}
+
+void
+TrackingText::set_offset (Duple const & d)
+{
+	offset = d;
+}