From 3accf1d2af0834cb2c13df0e6de085a2ce7d521c Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Thu, 26 Jun 2014 15:07:12 -0400
Subject: [PATCH] new API for TrackingText and similar items

---
 libs/canvas/canvas.cc       | 24 ++++++++++++++++++++++++
 libs/canvas/canvas/canvas.h | 19 +++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/libs/canvas/canvas.cc b/libs/canvas/canvas.cc
index fe42fd4b07..27ad1f4964 100644
--- a/libs/canvas/canvas.cc
+++ b/libs/canvas/canvas.cc
@@ -767,6 +767,28 @@ GtkCanvas::on_button_release_event (GdkEventButton* ev)
 	return deliver_event (reinterpret_cast<GdkEvent*>(&copy));
 }
 
+bool
+GtkCanvas::get_mouse_position (Duple& winpos) const
+{
+	int x;
+	int y;
+	Gdk::ModifierType mask;
+	Glib::RefPtr<Gdk::Window> self = Glib::RefPtr<Gdk::Window>::cast_const (get_window ());
+
+	if (!self) {
+		std::cerr << " no self window\n";
+		winpos = Duple (0, 0);
+		return false;
+	}
+
+	Glib::RefPtr<Gdk::Window> win = self->get_pointer (x, y, mask);
+
+	winpos.x = x;
+	winpos.y = y;
+
+	return true;
+}
+
 /** Handler for GDK motion events.
  *  @param ev Event.
  *  @return true if the event was handled.
@@ -788,6 +810,8 @@ GtkCanvas::on_motion_notify_event (GdkEventMotion* ev)
 
 	DEBUG_TRACE (PBD::DEBUG::CanvasEvents, string_compose ("canvas motion @ %1, %2 canvas @ %3, %4\n", ev->x, ev->y, copy.motion.x, copy.motion.y));
 
+	MouseMotion (point); /* EMIT SIGNAL */
+
 	pick_current_item (point, ev->state);
 
 	/* Now deliver the motion event.  It may seem a little inefficient
diff --git a/libs/canvas/canvas/canvas.h b/libs/canvas/canvas/canvas.h
index 9b35f0e5f8..e084d18566 100644
--- a/libs/canvas/canvas/canvas.h
+++ b/libs/canvas/canvas/canvas.h
@@ -113,6 +113,23 @@ public:
         virtual Coord width () const = 0;
         virtual Coord height () const = 0;
 
+	/** Store the coordinates of the mouse pointer in window coordinates in
+	   @param winpos. Return true if the position was within the window,
+	   false otherwise.
+	*/
+	virtual bool get_mouse_position (Duple& winpos) const = 0;
+
+	/** Signal to be used by items that need to track the mouse position
+	   within the window.
+	*/
+	sigc::signal<void,Duple const&> MouseMotion;
+
+	/** Ensures that the position given by @param winpos (in window
+	    coordinates) is within the current window area, possibly reduced by
+	    @param border.
+	*/
+	Duple clamp_to_window (Duple const& winpos, Duple border = Duple());
+
         void zoomed();
     
         std::string indent() const;
@@ -150,6 +167,8 @@ public:
 	Coord width() const;
 	Coord height() const;
 
+	bool get_mouse_position (Duple& winpos) const;
+
 protected:
 	bool on_scroll_event (GdkEventScroll *);
 	bool on_expose_event (GdkEventExpose *);