From d870fef12284d3d2b988c18a4115d8f5ba3b1458 Mon Sep 17 00:00:00 2001
From: "Owen W. Taylor" <otaylor@fishsoup.net>
Date: Sat, 13 Nov 2010 09:08:03 -0500
Subject: [PATCH] StBoxLayout: report correct paint volume when scrolled

When scrolled, st_box_layout_apply_transform() includes the scroll
offset and affects paint volumes. This is right for our children, but
our paint volume is determined by our allocation and borders and
doesn't scroll, so we need to reverse-compensate, the same as we do
when painting.

https://bugzilla.gnome.org/show_bug.cgi?id=630932
---
 src/st/st-box-layout.c | 79 +++++++++++++++++++++++++++++-------------
 1 file changed, 55 insertions(+), 24 deletions(-)

diff --git a/src/st/st-box-layout.c b/src/st/st-box-layout.c
index 3a912fa97..ae26cd76d 100644
--- a/src/st/st-box-layout.c
+++ b/src/st/st-box-layout.c
@@ -876,29 +876,39 @@ st_box_layout_apply_transform (ClutterActor *a,
   cogl_matrix_translate (m, (int) -x, (int) -y, 0);
 }
 
+/* If we are translated, then we need to translate back before chaining
+ * up or the background and borders will be drawn in the wrong place */
+static void
+get_border_paint_offsets (StBoxLayout *self,
+                          double      *x,
+                          double      *y)
+{
+  StBoxLayoutPrivate *priv = self->priv;
+
+  if (priv->hadjustment)
+    *x = st_adjustment_get_value (priv->hadjustment);
+  else
+    *x = 0;
+
+  if (priv->vadjustment)
+    *y = st_adjustment_get_value (priv->vadjustment);
+  else
+    *y = 0;
+}
+
 
 static void
 st_box_layout_paint (ClutterActor *actor)
 {
-  StBoxLayoutPrivate *priv = ST_BOX_LAYOUT (actor)->priv;
+  StBoxLayout *self = ST_BOX_LAYOUT (actor);
+  StBoxLayoutPrivate *priv = self->priv;
   StThemeNode *theme_node = st_widget_get_theme_node (ST_WIDGET (actor));
   GList *l, *children;
   gdouble x, y;
   ClutterActorBox allocation_box;
   ClutterActorBox content_box;
 
-  if (priv->hadjustment)
-    x = st_adjustment_get_value (priv->hadjustment);
-  else
-    x = 0;
-
-  if (priv->vadjustment)
-    y = st_adjustment_get_value (priv->vadjustment);
-  else
-    y = 0;
-
-  /* If we are translated, then we need to translate back before chaining
-   * up or the background and borders will be drawn in the wrong place */
+  get_border_paint_offsets (self, &x, &y);
   if (x != 0 || y != 0)
     {
       cogl_push_matrix ();
@@ -950,23 +960,15 @@ static void
 st_box_layout_pick (ClutterActor       *actor,
                     const ClutterColor *color)
 {
-  StBoxLayoutPrivate *priv = ST_BOX_LAYOUT (actor)->priv;
+  StBoxLayout *self = ST_BOX_LAYOUT (actor);
+  StBoxLayoutPrivate *priv = self->priv;
   StThemeNode *theme_node = st_widget_get_theme_node (ST_WIDGET (actor));
   GList *l, *children;
   gdouble x, y;
   ClutterActorBox allocation_box;
   ClutterActorBox content_box;
 
-  if (priv->hadjustment)
-    x = st_adjustment_get_value (priv->hadjustment);
-  else
-    x = 0;
-
-  if (priv->vadjustment)
-    y = st_adjustment_get_value (priv->vadjustment);
-  else
-    y = 0;
-
+  get_border_paint_offsets (self, &x, &y);
   if (x != 0 || y != 0)
     {
       cogl_push_matrix ();
@@ -1011,6 +1013,34 @@ st_box_layout_pick (ClutterActor       *actor,
     cogl_clip_pop ();
 }
 
+static gboolean
+st_box_layout_get_paint_volume (ClutterActor       *actor,
+                                ClutterPaintVolume *volume)
+{
+  StBoxLayout *self = ST_BOX_LAYOUT (actor);
+  gdouble x, y;
+
+  CLUTTER_ACTOR_CLASS (st_box_layout_parent_class)->get_paint_volume (actor, volume);
+
+  /* When scrolled, st_box_layout_apply_transform() includes the scroll offset
+   * and affects paint volumes. This is right for our children, but our paint volume
+   * is determined by our allocation and borders and doesn't scroll, so we need
+   * to reverse-compensate here, the same as we do when painting.
+   */
+  get_border_paint_offsets (self, &x, &y);
+  if (x != 0 || y != 0)
+    {
+      ClutterVertex origin;
+
+      clutter_paint_volume_get_origin (volume, &origin);
+      origin.x += x;
+      origin.y += y;
+      clutter_paint_volume_set_origin (volume, &origin);
+    }
+
+  return TRUE;
+}
+
 static void
 st_box_layout_style_changed (StWidget *self)
 {
@@ -1047,6 +1077,7 @@ st_box_layout_class_init (StBoxLayoutClass *klass)
   actor_class->apply_transform = st_box_layout_apply_transform;
 
   actor_class->paint = st_box_layout_paint;
+  actor_class->get_paint_volume = st_box_layout_get_paint_volume;
   actor_class->pick = st_box_layout_pick;
 
   widget_class->style_changed = st_box_layout_style_changed;