more profound changes to canvas scrolling, in particular find appropriate ScrollGroup for Canvas::{window,canvas}_to_{canvas,window}()

gtk2_ardour/editor.cc

@@ -2421,21 +2421,31 @@ Editor::get_state ()
 	return *node;
 }
 
-
-
-/** @param y y offset from the top of all trackviews.
+/** @param y y is in canvas coordinate space, in pixel units
+ *
  *  @return pair: TimeAxisView that y is over, layer index.
+ *
  *  TimeAxisView may be 0.  Layer index is the layer number if the TimeAxisView is valid and is
  *  in stacked or expanded region display mode, otherwise 0.
  */
 std::pair<TimeAxisView *, double>
 Editor::trackview_by_y_position (double y)
 {
-	for (TrackViewList::iterator iter = track_views.begin(); iter != track_views.end(); ++iter) {
+	/* convert y into an offset within the trackview group */
 
-		std::pair<TimeAxisView*, double> const r = (*iter)->covers_y_position (y);
-		if (r.first) {
-			return r;
+	ArdourCanvas::Duple top_of_trackviews_canvas = _trackview_group->item_to_canvas (ArdourCanvas::Duple (0, 0));
+	
+	if (y >= top_of_trackviews_canvas.y) {
+		
+		y -= top_of_trackviews_canvas.y;
+
+		for (TrackViewList::iterator iter = track_views.begin(); iter != track_views.end(); ++iter) {
+			
+			std::pair<TimeAxisView*, double> const r = (*iter)->covers_y_position (y);
+			
+			if (r.first) {
+				return r;
+			}
 		}
 	}
 

gtk2_ardour/editor.h

@@ -744,9 +744,6 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	/* The group containing all trackviews. */
 	ArdourCanvas::Group* _trackview_group;
 
-	/* The group used for region motion.  Sits on top of _trackview_group */
-	ArdourCanvas::Group* _region_motion_group;
-
         /* a rect that sits at the bottom of all tracks to act as a drag-no-drop/clickable
 	 * target area.
 	 */

gtk2_ardour/editor_canvas.cc

@@ -116,12 +116,8 @@ Editor::initialize_canvas ()
 	CANVAS_DEBUG_NAME (time_line_group, "time line group");
 
 	_trackview_group = new ArdourCanvas::Group (hv_scroll_group);
-	//_trackview_group->set_scroll_sensitivity (ArdourCanvas::Group::ScrollSensitivity (ArdourCanvas::Group::ScrollsVertically|ArdourCanvas::Group::ScrollsHorizontally));	
 	CANVAS_DEBUG_NAME (_trackview_group, "Canvas TrackViews");
 	
-	_region_motion_group = new ArdourCanvas::Group (_trackview_group);
-	CANVAS_DEBUG_NAME (_region_motion_group, "Canvas Region Motion");
-
 	/* TIME BAR CANVAS */
 	
 	_time_markers_group = new ArdourCanvas::Group (h_scroll_group);
@@ -453,7 +449,7 @@ Editor::drop_paths (const RefPtr<Gdk::DragContext>& context,
 
 	if (convert_drop_to_paths (paths, context, x, y, data, info, time) == 0) {
 
-		/* D-n-D coordinates are window-relative, so convert to "world" coordinates
+		/* D-n-D coordinates are window-relative, so convert to canvas coordinates
 		 */
 
 		ev.type = GDK_BUTTON_RELEASE;

gtk2_ardour/editor_drag.cc

@@ -1,4 +1,4 @@
-/*
+*
     Copyright (C) 2009 Paul Davis
 
     This program is free software; you can redistribute it and/or modify
@@ -40,6 +40,8 @@
 #include "ardour/region_factory.h"
 #include "ardour/session.h"
 
+#include "canvas/scroll_group.h"
+
 #include "editor.h"
 #include "i18n.h"
 #include "keyboard.h"
@@ -654,7 +656,7 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
 	pair<TimeAxisView*, double> const r = _editor->trackview_by_y_position (_drags->current_pointer_y ());
 	TimeAxisView* tv = r.first;
 
-	if (tv) {
+	if (tv && tv->view()) {
 		double layer = r.second;
 	
 		if (first_move && tv->view()->layer_display() == Stacked) {
@@ -700,22 +702,9 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
 		}
 
 		if (first_move) {
-
 			rv->drag_start (); 
-
-			/* Reparent to a non scrolling group so that we can keep the
-			   region selection above all time axis views.
-			   Reparenting means that we will have to move the region view
-			   within its new parent, as the two parent groups have different coordinates.
-			*/
-
-			ArdourCanvas::Group* rvg = rv->get_canvas_group();
-			Duple rv_canvas_offset = rvg->item_to_canvas (Duple (0,0));
-
-			rv->get_canvas_group()->reparent (_editor->_region_motion_group);
-
 			rv->fake_set_opaque (true);
-			rvg->set_position (rv_canvas_offset);
+			rv->raise_to_top ();
 		}
 
 		/* If we have moved tracks, we'll fudge the layer delta so that the
@@ -730,7 +719,13 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
 
 		if (tv) {
 
-			/* The TimeAxisView that this region is now on */
+			int track_index = i->time_axis_view + delta_time_axis_view;
+			 
+			if (track_index < 0 || track_index >= (int) _time_axis_views.size()) {
+				continue;
+			}
+
+			/* The TimeAxisView that this region is now over */
 			TimeAxisView* current_tv = _time_axis_views[i->time_axis_view + delta_time_axis_view];
 
 			/* Ensure it is moved from stacked -> expanded if appropriate */
@@ -762,39 +757,50 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
 			if (_brushing) {
 				_editor->mouse_brush_insert_region (rv, pending_region_position);
 			} else {
-				double x = 0;
-				double y = 0;
-
-				/* Get the y coordinate of the top of the track that this region is now on */
-				current_tv->canvas_display()->item_to_canvas (x, y);
+				Duple track_origin;
 
+				/* Get the y coordinate of the top of the track that this region is now over */
+				track_origin = current_tv->canvas_display()->item_to_canvas (track_origin);
+				
 				/* And adjust for the layer that it should be on */
 				StreamView* cv = current_tv->view ();
 				switch (cv->layer_display ()) {
 				case Overlaid:
 					break;
 				case Stacked:
-					y += (cv->layers() - i->layer - 1) * cv->child_height ();
+					track_origin.y += (cv->layers() - i->layer - 1) * cv->child_height ();
 					break;
 				case Expanded:
-					y += (cv->layers() - i->layer - 0.5) * 2 * cv->child_height ();
+					track_origin.y += (cv->layers() - i->layer - 0.5) * 2 * cv->child_height ();
 					break;
 				}
 
+				/* need to get the parent of the regionview
+				 * canvas group and get its position in
+				 * equivalent coordinate space as the trackview
+				 * we are now dragging over.
+				 */
+				
 				/* Now move the region view */
-				rv->move (x_delta, y - rv->get_canvas_group()->position().y);
+				rv->move (x_delta, track_origin.y - rv->get_canvas_group()->item_to_canvas (Duple (0, 0)).y);
 			}
 		} else {
-			double y = 0;
-			double x = 0;
-			
-			TimeAxisView* last = _time_axis_views.back();
-			last->canvas_display()->item_to_canvas (x, y);
-			y += last->effective_height();
-			rv->move (x_delta, y - rv->get_canvas_group()->position().y);
-			i->time_axis_view = -1;
-		}
 
+			/* Only move the region into the empty dropzone at the bottom if the pointer
+			 * is down there.
+			 */
+
+			if (_drags->current_pointer_y() >= _editor->get_trackview_group()->item_to_canvas (Duple (0,0)).y) {
+				Duple track_origin;
+				
+				TimeAxisView* last = _time_axis_views.back();
+				track_origin = last->canvas_display()->item_to_canvas (track_origin);
+				track_origin.y += last->effective_height();
+				rv->move (x_delta, track_origin.y - rv->get_canvas_group()->item_to_canvas (Duple (0,0)).y);
+				i->time_axis_view = -1;
+			}
+		}
+		
 	} /* foreach region */
 
 	_total_x_delta += x_delta;

gtk2_ardour/editor_mouse.cc

@@ -140,12 +140,6 @@ Editor::window_event_sample (GdkEvent const * event, double* pcx, double* pcy) c
 		return 0;
 	}
 
-	/* adjust for scrolling (the canvas used by Ardour has global scroll
-	 * disabled, so we have to do the adjustment explicitly).
-	 */
-
-	d.translate (ArdourCanvas::Duple (horizontal_adjustment.get_value(), vertical_adjustment.get_value()));
-
 	/* event coordinates are in window units, so convert to canvas
 	 */
 
@@ -2710,8 +2704,6 @@ Editor::add_region_drag (ArdourCanvas::Item* item, GdkEvent*, RegionView* region
 		return;
 	}
 
-	_region_motion_group->raise_to_top ();
-
 	if (Config->get_edit_mode() == Splice) {
 		_drags->add (new RegionSpliceDrag (this, item, region_view, selection->regions.by_layer()));
 	} else {
@@ -2728,8 +2720,6 @@ Editor::add_region_copy_drag (ArdourCanvas::Item* item, GdkEvent*, RegionView* r
 		return;
 	}
 
-	_region_motion_group->raise_to_top ();
-
 	_drags->add (new RegionMoveDrag (this, item, region_view, selection->regions.by_layer(), false, true));
 }
 

gtk2_ardour/editor_ops.cc

@@ -1333,8 +1333,6 @@ Editor::scroll_tracks_up_line ()
 bool
 Editor::scroll_down_one_track ()
 {
-	double vertical_pos = vertical_adjustment.get_value () + vertical_adjustment.get_page_size() - 1.0; 
-
 	TrackViewList::reverse_iterator next = track_views.rend();
 	std::pair<TimeAxisView*,double> res;
 
@@ -1343,7 +1341,8 @@ Editor::scroll_down_one_track ()
 			continue;
 		}
 		
-		res = (*t)->covers_y_position (vertical_pos);
+		/* find the trackview at the bottom of the trackview group */
+		res = (*t)->covers_y_position (_visible_canvas_height);
 
 		if (res.first) {
 			break;
@@ -1376,7 +1375,8 @@ Editor::scroll_up_one_track ()
 			continue;
 		}
 
-		res = (*t)->covers_y_position(vertical_pos);
+		/* find the trackview at the top of the trackview group */
+		res = (*t)->covers_y_position (0);
 		
 		if (res.first) {
 			break;

gtk2_ardour/region_view.cc

@@ -694,7 +694,18 @@ RegionView::move (double x_delta, double y_delta)
 		return;
 	}
 
-	get_canvas_group()->move (ArdourCanvas::Duple (x_delta, y_delta));
+	/* items will not prevent Item::move() moving
+	 * them to a negative x-axis coordinate, which
+	 * is legal, but we don't want that here.
+	 */
+
+	ArdourCanvas::Item *item = get_canvas_group ();
+	
+	if (item->position().x + x_delta < 0) {
+		x_delta = -item->position().x; /* move it to zero */
+	}
+
+	item->move (ArdourCanvas::Duple (x_delta, y_delta));
 
 	/* note: ghosts never leave their tracks so y_delta for them is always zero */
 

gtk2_ardour/time_axis_view.cc

@@ -1151,9 +1151,12 @@ TimeAxisView::color_handler ()
 }
 
 /** @return Pair: TimeAxisView, layer index.
- * TimeAxisView is non-0 if this object covers y, or one of its children does.
+ * TimeAxisView is non-0 if this object covers @param y, or one of its children
+ * does. @param y is an offset from the top of the trackview area.
+ *
  * If the covering object is a child axis, then the child is returned.
  * TimeAxisView is 0 otherwise.
+ *
  * Layer index is the layer number (possibly fractional) if the TimeAxisView is valid
  * and is in stacked or expanded * region display mode, otherwise 0.
  */

libs/canvas/canvas.cc

@@ -207,13 +207,53 @@ Canvas::item_changed (Item* item, boost::optional<Rect> pre_change_bounding_box)
 Duple
 Canvas::window_to_canvas (Duple const & d) const
 {
+	/* Find the scroll group that covers d (a window coordinate). Scroll groups are only allowed
+	 * as children of the root group, so we just scan its first level
+	 * children and see what we can find.
+	 */
+
+	std::list<Item*> const& root_children (_root.items());
+	ScrollGroup* sg = 0;
+
+	for (std::list<Item*>::const_iterator i = root_children.begin(); i != root_children.end(); ++i) {
+		if (((sg = dynamic_cast<ScrollGroup*>(*i)) != 0) && sg->covers_window (d)) {
+			break;
+		}
+	}
+
+	if (sg) {
+		return d.translate (sg->scroll_offset());
+	}
+
+	/* fallback to global canvas offset ... it would be nice to remove this */
+
 	return d.translate (_scroll_offset);
 }
 
 Duple
 Canvas::canvas_to_window (Duple const & d, bool rounded) const
 {
-	Duple wd = d.translate (-_scroll_offset);
+	/* Find the scroll group that covers d (a canvas coordinate). Scroll groups are only allowed
+	 * as children of the root group, so we just scan its first level
+	 * children and see what we can find.
+	 */
+
+	std::list<Item*> const& root_children (_root.items());
+	ScrollGroup* sg = 0;
+	Duple wd;
+
+	for (std::list<Item*>::const_iterator i = root_children.begin(); i != root_children.end(); ++i) {
+		if (((sg = dynamic_cast<ScrollGroup*>(*i)) != 0) && sg->covers_canvas (d)) {
+			break;
+		}
+	}
+	
+
+	if (sg) {
+		wd = d.translate (-sg->scroll_offset());
+	} else {
+		wd = d.translate (-_scroll_offset);
+	}
 
 	/* Note that this intentionally almost always returns integer coordinates */
 
@@ -225,29 +265,6 @@ Canvas::canvas_to_window (Duple const & d, bool rounded) const
 	return wd;
 }
 
-Rect
-Canvas::window_to_canvas (Rect const & r) const
-{
-	return r.translate (Duple (_scroll_offset.x, _scroll_offset.y));
-}
-
-Rect
-Canvas::canvas_to_window (Rect const & r, bool rounded) const
-{
-	Rect wr = r.translate (Duple (-_scroll_offset.x, -_scroll_offset.y));
-
-	/* Note that this intentionally almost always returns integer coordinates */
-
-	if (rounded) {
-		wr.x0 = round (wr.x0);
-		wr.x1 = round (wr.x1);
-		wr.y0 = round (wr.y0);
-		wr.y1 = round (wr.y1);
-	}
-
-	return wr;
-}	
-
 /** Called when an item has moved.
  *  @param item Item that has moved.
  *  @param pre_change_parent_bounding_box The bounding box of the item before

libs/canvas/canvas/canvas.h

@@ -90,8 +90,7 @@ public:
 	void item_moved (Item *, boost::optional<Rect>);
 
         virtual Cairo::RefPtr<Cairo::Context> context () = 0;
-        Rect canvas_to_window (Rect const&, bool rounded = true) const;
-        Rect window_to_canvas (Rect const&) const;
+
         Duple canvas_to_window (Duple const&, bool rounded = true) const;
         Duple window_to_canvas (Duple const&) const;
 

libs/canvas/canvas/item.h

@@ -129,6 +129,10 @@ public:
 		return _position;
 	}
 
+	Duple window_origin() const;
+
+	ScrollGroup* scroll_parent() const { return _scroll_parent; }
+
 	boost::optional<Rect> bounding_box () const;
         Coord height() const;
         Coord width() const;

libs/canvas/canvas/scroll_group.h

@@ -37,6 +37,9 @@ class LIBCANVAS_API ScrollGroup : public Group
 	void scroll_to (Duple const& d);
 	Duple scroll_offset() const { return _scroll_offset; }
 
+	bool covers_canvas (Duple const& d) const;
+	bool covers_window (Duple const& d) const;
+
   private:
 	ScrollSensitivity _scroll_sensitivity;
 	Duple             _scroll_offset;

libs/canvas/item.cc

@@ -82,6 +82,20 @@ Item::~Item ()
 	}
 }
 
+Duple
+Item::window_origin () const 
+{
+	/* This is slightly subtle. Our _position is in the coordinate space of 
+	   our parent. So to find out where that is in window coordinates, we
+	   have to ask our parent.
+	*/
+	if (_parent) {
+		return _parent->item_to_window (_position);
+	} else {
+		return _parent->item_to_window (Duple (0,0));
+	}
+}
+
 ArdourCanvas::Rect
 Item::item_to_parent (ArdourCanvas::Rect const & r) const
 {

libs/canvas/scroll_group.cc

@@ -49,3 +49,29 @@ ScrollGroup::scroll_to (Duple const& d)
 		_scroll_offset.y = d.y;
 	}
 }
+
+bool
+ScrollGroup::covers_canvas (Duple const& d) const
+{
+	boost::optional<Rect> r = bounding_box ();
+
+	if (!r) {
+		return false;
+	}
+
+	return r->contains (d);
+}
+
+bool
+ScrollGroup::covers_window (Duple const& d) const
+{
+	boost::optional<Rect> r = bounding_box ();
+
+	if (!r) {
+		return false;
+	}
+
+	Rect w = r->translate (-_scroll_offset);
+
+	return w.contains (d);
+}