[gtk+] widget: propagate scale factor upon reparenting a widget

[Daniel Boles <dboles src gnome org>]

commit 72801a27eba06c542136aee74f3af70db5039ac7
Author: Lionel Landwerlin <lionel g landwerlin intel com>
Date:   Mon Jan 9 00:11:29 2017 +0000

    widget: propagate scale factor upon reparenting a widget
    
    When a widget is created, its default scale is the scale of the
    primary screen (for instance 2). But once parented to another widget
    its scale factor should be the one of its parent (if parented to a
    widget on a screen at scale factor 1, it should be 1).
    
    The problem is that we don't emit the notify::scale-factor signal when
    reparenting happens.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=776821

 gtk/gtkwidget.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 5e406a5..838630d 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -606,6 +606,8 @@ struct _GtkStateData
 {
   guint         flags_to_set;
   guint         flags_to_unset;
+
+  gint          old_scale_factor;
 };
 
 /* --- prototypes --- */
@@ -7882,6 +7884,7 @@ gtk_widget_update_state_flags (GtkWidget     *widget,
     {
       GtkStateData data;
 
+      data.old_scale_factor = gtk_widget_get_scale_factor (widget);
       data.flags_to_set = flags_to_set;
       data.flags_to_unset = flags_to_unset;
 
@@ -8304,6 +8307,8 @@ gtk_widget_set_sensitive (GtkWidget *widget,
     {
       GtkStateData data;
 
+      data.old_scale_factor = gtk_widget_get_scale_factor (widget);
+
       if (sensitive)
         {
           data.flags_to_set = 0;
@@ -8399,6 +8404,8 @@ gtk_widget_set_parent (GtkWidget *widget,
       return;
     }
 
+  data.old_scale_factor = gtk_widget_get_scale_factor (widget);
+
   /* keep this function in sync with gtk_menu_attach_to_widget()
    */
 
@@ -11120,6 +11127,7 @@ gtk_widget_propagate_state (GtkWidget    *widget,
   GtkStateFlags new_flags, old_flags = priv->state_flags;
   GtkStateData child_data;
   GtkWidget *child;
+  gint new_scale_factor = gtk_widget_get_scale_factor (widget);
 
   priv->state_flags |= data->flags_to_set;
   priv->state_flags &= ~(data->flags_to_unset);
@@ -11140,6 +11148,9 @@ gtk_widget_propagate_state (GtkWidget    *widget,
 
   new_flags = priv->state_flags;
 
+  if (data->old_scale_factor != new_scale_factor)
+    _gtk_widget_scale_changed (widget);
+
   if (old_flags != new_flags)
     {
       g_object_ref (widget);
@@ -11193,6 +11204,7 @@ gtk_widget_propagate_state (GtkWidget    *widget,
 
 
       /* Make sure to only propagate the right states further */
+      child_data.old_scale_factor = new_scale_factor;
       child_data.flags_to_set = data->flags_to_set & GTK_STATE_FLAGS_DO_PROPAGATE;
       child_data.flags_to_unset = data->flags_to_unset & GTK_STATE_FLAGS_DO_PROPAGATE;