[glom] Canvas_PrintLayout: Selecting unselects others. Allow shift-clicking.

[Murray Cumming <murrayc src gnome org>]

commit e6a8d485ca46e05753201b13372d2ab5a263c02b
Author: Murray Cumming <murrayc murrayc com>
Date:   Sun Aug 7 10:48:55 2011 +0200

    Canvas_PrintLayout: Selecting unselects others. Allow shift-clicking.
    
    * glom/utility_widgets/canvas/canvas_item_movable.[h|cc]:
    signal_selected(): Also send the item (this), to avoid the need for
    awkward (due to keeping a reference) sigc::bind()ing of RefPtr<>s.
    Send a bool group_select parameter too, so we know if the button
    press (corresponding to the button release) was with the shift key
    held down.
    * glom/utility_widgets/canvas/canvas_editable.[h|cc]:
    on_item_selected(): Deselect other already-selected items if
    the select was not with shift held down.

 ChangeLog                                          |   14 +++++++++++
 glom/utility_widgets/canvas/canvas_editable.cc     |   19 ++++++++++++++-
 glom/utility_widgets/canvas/canvas_editable.h      |    2 +-
 glom/utility_widgets/canvas/canvas_item_movable.cc |   25 +++++++++++++++++--
 glom/utility_widgets/canvas/canvas_item_movable.h  |    9 +++++-
 5 files changed, 62 insertions(+), 7 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index ebe0a01..a627597 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2011-08-07  Murray Cumming  <murrayc murrayc com>
+
+	Canvas_PrintLayout: Selecting unselects others. Allow shift-clicking.
+
+	* glom/utility_widgets/canvas/canvas_item_movable.[h|cc]:
+	signal_selected(): Also send the item (this), to avoid the need for 
+	awkward (due to keeping a reference) sigc::bind()ing of RefPtr<>s.
+	Send a bool group_select parameter too, so we know if the button 
+	press (corresponding to the button release) was with the shift key 
+	held down.
+	* glom/utility_widgets/canvas/canvas_editable.[h|cc]:
+	on_item_selected(): Deselect other already-selected items if 
+	the select was not with shift held down.
+
 2011-08-06  Murray Cumming  <murrayc murrayc com>
 
 	CanvasItemMovable: set_selected(): Do not emit the signal here.
diff --git a/glom/utility_widgets/canvas/canvas_editable.cc b/glom/utility_widgets/canvas/canvas_editable.cc
index 465facb..7e2f6dd 100644
--- a/glom/utility_widgets/canvas/canvas_editable.cc
+++ b/glom/utility_widgets/canvas/canvas_editable.cc
@@ -182,8 +182,25 @@ CanvasEditable::type_signal_selection_changed CanvasEditable::signal_selection_c
   return m_signal_selection_changed;
 }
 
-void CanvasEditable::on_item_selected()
+void CanvasEditable::on_item_selected(const Glib::RefPtr<CanvasItemMovable>& item, bool group_select)
 {
+  const bool selected = !item->get_selected();
+
+  if(!group_select)
+  {
+    //Make sure that all other items are deselected first:
+    const type_vec_items items = get_selected_items();
+    for(type_vec_items::const_iterator iter = items.begin();
+      iter != items.end(); ++iter)
+    {
+      Glib::RefPtr<CanvasItemMovable> selected_item = *iter;
+      if(selected_item)
+        selected_item->set_selected(false);
+    }
+  }
+
+  item->set_selected(!selected);
+
   m_signal_selection_changed.emit();
 }
 
diff --git a/glom/utility_widgets/canvas/canvas_editable.h b/glom/utility_widgets/canvas/canvas_editable.h
index 65e5b30..03a7582 100644
--- a/glom/utility_widgets/canvas/canvas_editable.h
+++ b/glom/utility_widgets/canvas/canvas_editable.h
@@ -85,7 +85,7 @@ public:
 
 private:
   
-  void on_item_selected();
+  void on_item_selected(const Glib::RefPtr<CanvasItemMovable>& item, bool group_select);
 
   static Glib::RefPtr<Goocanvas::Item> get_parent_container_or_self(const Glib::RefPtr<Goocanvas::Item>& item);
 
diff --git a/glom/utility_widgets/canvas/canvas_item_movable.cc b/glom/utility_widgets/canvas/canvas_item_movable.cc
index 334370b..f8eb588 100644
--- a/glom/utility_widgets/canvas/canvas_item_movable.cc
+++ b/glom/utility_widgets/canvas/canvas_item_movable.cc
@@ -43,7 +43,8 @@ CanvasItemMovable::CanvasItemMovable()
   m_drag_start_position_x(0.0), m_drag_start_position_y(0.0),
   m_grid(0),
   m_allow_vertical_movement(true), m_allow_horizontal_movement(true),
-  m_selected(false)
+  m_selected(false),
+  m_shift_click(false)
 {
    //TODO: Remove this when goocanvas is fixed, so the goocanvasmm constructor can connect default signal handlers:
   /*
@@ -63,6 +64,10 @@ CanvasItemMovable::~CanvasItemMovable()
 
 bool CanvasItemMovable::on_button_press_event(const Glib::RefPtr<Goocanvas::Item>& target, GdkEventButton* event)
 {
+  //std::cout << G_STRFUNC << ": DEBUG" << std::endl;
+
+  m_shift_click = false;
+
   switch(event->button)
   {
     case 1:
@@ -84,6 +89,12 @@ bool CanvasItemMovable::on_button_press_event(const Glib::RefPtr<Goocanvas::Item
       }
 
       m_dragging = true;
+
+      //Holding down shift when pressing the mouse down
+      //means that any selection (decided later) will be a multiple selection.
+      if(event->state & GDK_SHIFT_MASK)
+        m_shift_click = true;
+
       return true; // Handled.
       break;
     }
@@ -156,7 +167,11 @@ bool CanvasItemMovable::on_motion_notify_event(const Glib::RefPtr<Goocanvas::Ite
     const bool old_selected = get_selected();
     set_selected(true);
     if(!old_selected)
-      m_signal_selected.emit();
+    {
+      Glib::RefPtr<CanvasItemMovable> refThis(this);
+      refThis->reference();
+      m_signal_selected.emit(refThis, m_shift_click);
+    }
 
     m_signal_moved.emit();
 
@@ -168,6 +183,8 @@ bool CanvasItemMovable::on_motion_notify_event(const Glib::RefPtr<Goocanvas::Ite
 
 bool CanvasItemMovable::on_button_release_event(const Glib::RefPtr<Goocanvas::Item>& target, GdkEventButton* event)
 {
+  //std::cout << G_STRFUNC << ": DEBUG" << std::endl;
+
   if(!m_allow_vertical_movement && !m_allow_horizontal_movement)
     return false; // Not handled. Let it be handled by an item lower in the z order, or a parent group, if any.
 
@@ -202,7 +219,9 @@ bool CanvasItemMovable::on_button_release_event(const Glib::RefPtr<Goocanvas::It
   //Notify of the selection change, if any:
   if(selected != old_selected)
   {
-    m_signal_selected.emit();
+    Glib::RefPtr<CanvasItemMovable> refThis(this);
+    refThis->reference();
+    m_signal_selected.emit(refThis, m_shift_click);
   }
 
   return true;
diff --git a/glom/utility_widgets/canvas/canvas_item_movable.h b/glom/utility_widgets/canvas/canvas_item_movable.h
index 152b0b4..4e7b168 100644
--- a/glom/utility_widgets/canvas/canvas_item_movable.h
+++ b/glom/utility_widgets/canvas/canvas_item_movable.h
@@ -71,9 +71,13 @@ public:
   type_signal_show_context signal_show_context();
 
   /** For instance,
-   *   void on_selected();
+   *
+   *   @param item The item (this item) that was selected/deseleted, for convenience.
+   *   @param group_select Whether the user selected this while pressing Shift to select multiple items.
+   *
+   *   void on_selected(bool group_select);
    */
-  typedef sigc::signal<void> type_signal_selected;
+  typedef sigc::signal<void, const Glib::RefPtr<CanvasItemMovable>&, bool> type_signal_selected;
 
   /** This signal is emitted if the user causes the item 
    * to be selected or deselected. See get_selected().
@@ -144,6 +148,7 @@ protected:
 private:
   bool m_allow_vertical_movement, m_allow_horizontal_movement;
   bool m_selected;
+  bool m_shift_click;
 
   type_signal_moved m_signal_moved;
   type_signal_show_context m_signal_show_context;