Start autoscroll in from the right-hand edge of the screen if the editor list is not in view, so that autoscroll kind-of works in this situation (#4473 and #4216).

git-svn-id: svn://localhost/ardour2/branches/3.0@10718 d708f5d6-7413-0410-9779-e7cbd77b26cf

2 files changed, 59 insertions, 1 deletions

diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index cc6917cf77..0450054bf0 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -1696,6 +1696,9 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	framecnt_t autoscroll_x_distance;
 	double autoscroll_y_distance;
 
+	bool _autoscroll_fudging;
+	int autoscroll_fudge_threshold () const;
+
 	static gint _autoscroll_canvas (void *);
 	bool autoscroll_canvas ();
 	void start_canvas_autoscroll (int x, int y);
diff --git a/gtk2_ardour/editor_canvas.cc b/gtk2_ardour/editor_canvas.cc
index 4d6945d6c0..ddbb1f0a12 100644
--- a/gtk2_ardour/editor_canvas.cc
+++ b/gtk2_ardour/editor_canvas.cc
@@ -479,12 +479,44 @@ Editor::drop_regions (const RefPtr<Gdk::DragContext>& /*context*/,
 	_drags->end_grab (0);
 }
 
+/** If the editor window is arranged such that the edge of the trackview is right up
+ *  against the edge of the screen, autoscroll will not work very well.  In this situation,
+ *  we start autoscrolling some distance in from the right-hand-side of the screen edge;
+ *  this is the distance at which that happens.
+ */
+int
+Editor::autoscroll_fudge_threshold () const
+{
+	return current_page_frames() / 6;
+}
+
 void
 Editor::maybe_autoscroll (bool allow_horiz, bool allow_vert)
 {
-	framepos_t rightmost_frame = leftmost_frame + current_page_frames();
 	bool startit = false;
 
+	/* Work out the distance between the right hand edge of the trackview and the edge of
+	   the monitor that it is on.
+	*/
+
+	Glib::RefPtr<Gdk::Window> gdk_window = get_window ();
+	Gdk::Rectangle window_rect;
+	gdk_window->get_frame_extents (window_rect);
+	
+	Glib::RefPtr<Gdk::Screen> screen = get_screen ();
+	Gdk::Rectangle root_rect;
+	screen->get_root_window()->get_frame_extents (root_rect);
+
+	Gtk::Allocation editor_list = _the_notebook.get_allocation ();
+
+	int distance = root_rect.get_x() + root_rect.get_width() - window_rect.get_x() - window_rect.get_width();
+	if (_the_notebook.is_visible ()) {
+		distance += editor_list.get_width();
+	}
+
+	/* Note whether we're fudging the autoscroll (see autoscroll_fudge_threshold) */
+	_autoscroll_fudging = (distance < autoscroll_fudge_threshold ());
+
 	double const ty = _drags->current_pointer_y() - get_trackview_group_vertical_offset ();
 
 	autoscroll_y = 0;
@@ -497,6 +529,11 @@ Editor::maybe_autoscroll (bool allow_horiz, bool allow_vert)
 		startit = true;
 	}
 
+	framepos_t rightmost_frame = leftmost_frame + current_page_frames();
+	if (_autoscroll_fudging) {
+		rightmost_frame -= autoscroll_fudge_threshold ();
+	}
+
 	if (_drags->current_pointer_frame() > rightmost_frame && allow_horiz) {
 		if (rightmost_frame < max_framepos) {
 			autoscroll_x = 1;
@@ -536,10 +573,28 @@ Editor::autoscroll_canvas ()
 	double new_pixel;
 	double target_pixel;
 
+	/* Work out whether the right-hand side of this window is next to the edge of the screen */
+
+	Glib::RefPtr<Gdk::Window> gdk_window = get_window ();
+	Gdk::Rectangle window_rect;
+	gdk_window->get_frame_extents (window_rect);
+	
+	Glib::RefPtr<Gdk::Screen> screen = get_screen ();
+	Gdk::Rectangle root_rect;
+	screen->get_root_window()->get_frame_extents (root_rect);
+
+	int distance = root_rect.get_x() + root_rect.get_width() - window_rect.get_x() - window_rect.get_width();
+	if (_the_notebook.is_visible ()) {
+		distance += _the_notebook.get_allocation().get_width();
+	}
+	
 	if (autoscroll_x_distance != 0) {
 
 		if (autoscroll_x > 0) {
 			autoscroll_x_distance = (_drags->current_pointer_frame() - (leftmost_frame + current_page_frames())) / 3;
+			if (_autoscroll_fudging) {
+				autoscroll_x_distance += autoscroll_fudge_threshold () / 3;
+			}
 		} else if (autoscroll_x < 0) {
 			autoscroll_x_distance = (leftmost_frame - _drags->current_pointer_frame()) / 3;