[glom] Print Layout: Correct drag position even when the layout is scrolled.

[Murray Cumming <murrayc src gnome org>]

commit 934ce9098698579dc7f569f1d1f3756d0dba05ce
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Aug 5 09:15:18 2011 +0200

    Print Layout: Correct drag position even when the layout is scrolled.
    
    * glom/mode_design/print_layouts/window_print_layout_edit.[h|cc]:
    Add and use canvas_convert_from_drag_pixels() to avoid the offset when
    dragging an item from the toolpalette to the canvas when the canvas is
    scrolled down.

 ChangeLog                                          |    9 +++++++
 .../print_layouts/window_print_layout_edit.cc      |   24 +++++++++++++++----
 .../print_layouts/window_print_layout_edit.h       |    2 +
 3 files changed, 30 insertions(+), 5 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 7843ee5..ffddbed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2011-08-05  Murray Cumming  <murrayc murrayc com>
+
+	Print Layout: Correct drag position even when the layout is scrolled.
+
+	* glom/mode_design/print_layouts/window_print_layout_edit.[h|cc]:
+	Add and use canvas_convert_from_drag_pixels() to avoid the offset when 
+	dragging an item from the toolpalette to the canvas when the canvas is 
+	scrolled down.
+
 2011-08-04  Murray Cumming  <murrayc murrayc com>
 
 	Print Layouts: Make corner and edges snap to the grid too.
diff --git a/glom/mode_design/print_layouts/window_print_layout_edit.cc b/glom/mode_design/print_layouts/window_print_layout_edit.cc
index 72f8dd0..a379d64 100644
--- a/glom/mode_design/print_layouts/window_print_layout_edit.cc
+++ b/glom/mode_design/print_layouts/window_print_layout_edit.cc
@@ -370,7 +370,7 @@ bool Window_PrintLayout_Edit::on_canvas_drag_motion(const Glib::RefPtr<Gdk::Drag
   //Move the temporary canvas item to the new position:
   double item_x = x;
   double item_y = y;
-  m_canvas.convert_from_pixels(item_x, item_y);
+  canvas_convert_from_drag_pixels(item_x, item_y);
 
   m_layout_item_dropping->set_xy(item_x, item_y);
 
@@ -427,6 +427,20 @@ sharedptr<LayoutItem> Window_PrintLayout_Edit::create_empty_item(PrintLayoutTool
   return layout_item;
 }
 
+void Window_PrintLayout_Edit::canvas_convert_from_drag_pixels(double& x, double& y) const
+{
+  //The canvas might be scrolled down in the viewport/scrolledwindow,
+  //so deal with that:
+  const double scroll_x = m_scrolled_window.get_hadjustment()->get_value();
+  const double scroll_y = m_scrolled_window.get_vadjustment()->get_value();
+  
+  x += scroll_x;
+  y += scroll_y;
+
+  m_canvas.convert_from_pixels(x, y);
+}
+
+
 void Window_PrintLayout_Edit::on_canvas_drag_data_received(const Glib::RefPtr<Gdk::DragContext>& drag_context, int x, int y, const Gtk::SelectionData& selection_data, guint /* info */, guint timestamp)
 {
   //This is called when an item is dropped on the canvas,
@@ -450,7 +464,7 @@ void Window_PrintLayout_Edit::on_canvas_drag_data_received(const Glib::RefPtr<Gd
 
         double item_x = x;
         double item_y = y;
-        m_canvas.convert_from_pixels(item_x, item_y);
+        canvas_convert_from_drag_pixels(item_x, item_y);
         m_layout_item_dropping->set_xy(item_x, item_y);
       }
     }
@@ -470,7 +484,7 @@ void Window_PrintLayout_Edit::on_canvas_drag_data_received(const Glib::RefPtr<Gd
     m_canvas.add_canvas_layout_item(item);
     double item_x = x;
     double item_y = y;
-    m_canvas.convert_from_pixels(item_x, item_y);
+    canvas_convert_from_drag_pixels(item_x, item_y);
     item->set_xy(item_x, item_y);
    
     if(m_layout_item_dropping)
@@ -677,7 +691,7 @@ void Window_PrintLayout_Edit::set_default_position(const sharedptr<LayoutItem>&
 
   double item_x = 10;
   double item_y = 10;
-  m_canvas.convert_from_pixels(item_x, item_y);
+  canvas_convert_from_drag_pixels(item_x, item_y);
   
   //TODO: This doesn't seem to actually work:
   while(get_is_item_at(item_x, item_y))
@@ -761,7 +775,7 @@ void Window_PrintLayout_Edit::on_menu_insert_line_vertical()
   /*
   double item_x = m_drop_x;
   double item_y = m_drop_y;
-  m_canvas.convert_from_pixels(item_x, item_y);
+  canvas_convert_from_drag_pixels(item_x, item_y);
   */
 
   // Note to translators: This is the default contents of a text item on a print layout: 
diff --git a/glom/mode_design/print_layouts/window_print_layout_edit.h b/glom/mode_design/print_layouts/window_print_layout_edit.h
index 0c6f2fe..038fac5 100644
--- a/glom/mode_design/print_layouts/window_print_layout_edit.h
+++ b/glom/mode_design/print_layouts/window_print_layout_edit.h
@@ -99,6 +99,8 @@ private:
 
   bool get_is_item_at(double x, double y);
   void set_default_position(const sharedptr<LayoutItem>& item);
+  
+  void canvas_convert_from_drag_pixels(double& x, double& y) const;
 
   //Box_DB_Table_Definition* m_box;
   Glib::ustring m_name_original;