[gtk+] Allow theme to set close button position in headerbars

[Matthias Clasen <matthiasc src gnome org>]

commit 54773ba45ba6348cc8c94e7fbab10049fac02884
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Sep 16 16:13:07 2013 -0400

    Allow theme to set close button position in headerbars
    
    This allows GTK+ applications with headerbars to fit in
    better in platforms that have window controls on the left.
    
    To use this, set -GtkWindow-decoration-button-layout: 'close:'
    in the theme.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706708

 gtk/gtkheaderbar.c |   42 ++++++++++++++++++++++++++++++++++++++----
 1 files changed, 38 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkheaderbar.c b/gtk/gtkheaderbar.c
index 400f34a..c1c1842 100644
--- a/gtk/gtkheaderbar.c
+++ b/gtk/gtkheaderbar.c
@@ -643,6 +643,27 @@ gtk_header_bar_get_preferred_height_for_width (GtkWidget *widget,
   gtk_header_bar_compute_size_for_opposing_orientation (widget, width, minimum_height, natural_height);
 }
 
+static gboolean
+close_button_at_end (GtkWidget *widget)
+{
+  gchar *layout_desc;
+  gboolean at_end;
+  gchar *p;
+
+  gtk_widget_style_get (gtk_widget_get_toplevel (widget),
+                        "decoration-button-layout", &layout_desc, NULL);
+
+  p = strchr (layout_desc, ':');
+  if (p && strstr (p, "close"))
+    at_end = TRUE;
+  else
+    at_end = FALSE;
+
+  g_free (layout_desc);
+
+  return at_end;
+}
+
 static void
 gtk_header_bar_size_allocate (GtkWidget     *widget,
                               GtkAllocation *allocation)
@@ -667,6 +688,9 @@ gtk_header_bar_size_allocate (GtkWidget     *widget,
   gint child_size;
   GtkTextDirection direction;
   GtkBorder css_borders;
+  gboolean at_end;
+
+  at_end = close_button_at_end (widget);
 
   gtk_widget_set_allocation (widget, allocation);
 
@@ -734,9 +758,9 @@ gtk_header_bar_size_allocate (GtkWidget     *widget,
       child_allocation.y = allocation->y + css_borders.top;
       child_allocation.height = height;
       if (packing == GTK_PACK_START)
-        x = allocation->x + css_borders.left;
+        x = allocation->x + css_borders.left + (at_end ? 0 : close_width);
       else
-        x = allocation->x + allocation->width - close_width - css_borders.right;
+        x = allocation->x + allocation->width - (at_end ? close_width : 0) - css_borders.right;
 
       if (packing == GTK_PACK_START)
        {
@@ -790,7 +814,10 @@ gtk_header_bar_size_allocate (GtkWidget     *widget,
         }
     }
 
-  side[GTK_PACK_END] += close_width;
+  if (at_end)
+    side[GTK_PACK_END] += close_width;
+  else
+    side[GTK_PACK_START] += close_width;
 
   child_allocation.y = allocation->y + css_borders.top;
   child_allocation.height = height;
@@ -822,14 +849,21 @@ gtk_header_bar_size_allocate (GtkWidget     *widget,
 
   if (priv->close_button)
     {
+      gboolean left;
+
       if (direction == GTK_TEXT_DIR_RTL)
+        left = at_end;
+      else
+        left = !at_end;
+
+      if (left)
         child_allocation.x = allocation->x + css_borders.left;
       else
         child_allocation.x = allocation->x + allocation->width - css_borders.right - close_button_width;
       child_allocation.width = close_button_width;
       gtk_widget_size_allocate (priv->close_button, &child_allocation);
 
-      if (direction == GTK_TEXT_DIR_RTL)
+      if (left)
         child_allocation.x = allocation->x + css_borders.left + close_button_width + priv->spacing;
       else
         child_allocation.x = allocation->x + allocation->width - css_borders.right - close_button_width - 
priv->spacing - separator_width;