[gtk+] treeview: if we are below rows that changed height: redraw

[Benjamin Otte <otte src gnome org>]

commit 4d5d915afe89429dd78b81c3806be027fc61eab1
Author: Kristian Rietveld <kris gtk org>
Date:   Tue Apr 5 21:09:10 2011 +0200

    treeview: if we are below rows that changed height: redraw
    
    We have to redraw if we are below a couple of rows that changed height
    in do_validate_rows().  This will still require a redraw for a large
    amount of cases, can we do better?  You would expect that a redraw of
    the tree view is not required when the dy changes with the same delta
    as the delta of the height accrued when validating the nodes.  This
    further optimization will likely require changes to the top_row/dy
    synchronization code.

 gtk/gtktreeview.c |   21 +++++++++++++++++++--
 1 files changed, 19 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index ed45e3b..4c62fa6 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -6631,6 +6631,7 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
   GTimer *timer;
   gint i = 0;
 
+  gint y = -1;
   gint prev_height = -1;
   gboolean fixed_height = TRUE;
 
@@ -6652,6 +6653,8 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
 
   do
     {
+      gboolean changed = FALSE;
+
       if (! GTK_RBNODE_FLAG_SET (tree_view->priv->tree->root, GTK_RBNODE_DESCENDANTS_INVALID))
 	{
 	  retval = FALSE;
@@ -6711,8 +6714,16 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
 	  gtk_tree_model_get_iter (tree_view->priv->model, &iter, path);
 	}
 
-      validated_area = validate_row (tree_view, tree, node, &iter, path) ||
-                       validated_area;
+      changed = validate_row (tree_view, tree, node, &iter, path);
+      validated_area = changed || validated_area;
+
+      if (changed)
+        {
+          gint offset = gtk_tree_view_get_row_y_offset (tree_view, tree, node);
+
+          if (y == -1 || y > offset)
+            y = offset;
+        }
 
       if (!tree_view->priv->fixed_height_check)
         {
@@ -6758,6 +6769,12 @@ do_validate_rows (GtkTreeView *tree_view, gboolean queue_resize)
        */
       gtk_tree_view_size_request (GTK_WIDGET (tree_view), &requisition, FALSE);
 
+      /* If rows above the current position have changed height, this has
+       * affected the current view and thus needs a redraw.
+       */
+      if (y != -1 && y < gtk_adjustment_get_value (tree_view->priv->vadjustment))
+        gtk_widget_queue_draw (GTK_WIDGET (tree_view));
+
       gtk_adjustment_set_upper (tree_view->priv->hadjustment,
                                 MAX (gtk_adjustment_get_upper (tree_view->priv->hadjustment), requisition.width));
       gtk_adjustment_set_upper (tree_view->priv->vadjustment,