[gtk+] css: Properly convert em, ex and rem to pixels

[Benjamin Otte <otte src gnome org>]

commit e35e6abbb2ea824afd6db2d54d10666cd23ad54c
Author: Benjamin Otte <otte redhat com>
Date:   Fri Feb 5 14:42:41 2016 +0100

    css: Properly convert em, ex and rem to pixels
    
    The previous code converted to pt.

 gtk/gtkcssnumbervalue.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkcssnumbervalue.c b/gtk/gtkcssnumbervalue.c
index 2524d46..17322e3 100644
--- a/gtk/gtkcssnumbervalue.c
+++ b/gtk/gtkcssnumbervalue.c
@@ -127,16 +127,17 @@ gtk_css_value_number_compute (GtkCssValue             *number,
       return _gtk_css_number_value_new (number->value * 96.0 * 0.039370078740157477,
                                         GTK_CSS_PX);
     case GTK_CSS_EM:
-      return _gtk_css_number_value_new (number->value *
+      return _gtk_css_number_value_new (number->value * 96.0 / 72.0 *
                                         get_base_font_size (property_id, provider, style, parent_style),
                                         GTK_CSS_PX);
     case GTK_CSS_EX:
       /* for now we pretend ex is half of em */
-      return _gtk_css_number_value_new (number->value * 0.5 * 
+      return _gtk_css_number_value_new (number->value * 0.5 * 96.0 / 72.0 *
                                         get_base_font_size (property_id, provider, style, parent_style),
                                         GTK_CSS_PX);
     case GTK_CSS_REM:
-      return _gtk_css_number_value_new (number->value * _gtk_css_font_size_get_default (provider),
+      return _gtk_css_number_value_new (number->value * 96.0 / 72.0 *
+                                        _gtk_css_font_size_get_default (provider),
                                         GTK_CSS_PX);
     case GTK_CSS_RAD:
       return _gtk_css_number_value_new (number->value * 360.0 / (2 * G_PI),