[gtk/css-animation-change] css: Avoid unneeded transition work

[Benjamin Otte <otte src gnome org>]

commit a1cacc590d2418e39481073f16c3709cad4309fa
Author: Benjamin Otte <otte benjamin googlemail com>
Date:   Sun Aug 18 15:57:09 2019 +0000

    css: Avoid unneeded transition work
    
    Add an early exit in the transition creation code when no transitions are given. In that case, both 
transition-duration and transition-delay are equal to their default value of 0, which means no transitions 
should run at all.

 gtk/gtkcssanimatedstyle.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkcssanimatedstyle.c b/gtk/gtkcssanimatedstyle.c
index c09ddb01ce..f1abcbe87e 100644
--- a/gtk/gtkcssanimatedstyle.c
+++ b/gtk/gtkcssanimatedstyle.c
@@ -272,11 +272,17 @@ gtk_css_animated_style_create_css_transitions (GSList              *animations,
   GtkCssValue *durations, *delays, *timing_functions;
   guint i;
 
-  transition_infos_set (transitions, gtk_css_style_get_value (base_style, 
GTK_CSS_PROPERTY_TRANSITION_PROPERTY));
-
   durations = gtk_css_style_get_value (base_style, GTK_CSS_PROPERTY_TRANSITION_DURATION);
   delays = gtk_css_style_get_value (base_style, GTK_CSS_PROPERTY_TRANSITION_DELAY);
   timing_functions = gtk_css_style_get_value (base_style, GTK_CSS_PROPERTY_TRANSITION_TIMING_FUNCTION);
+  /* early exit if transition-duration and transition-delay aren't set (default) */
+  if (_gtk_css_array_value_get_n_values (durations) == 1 &&
+      _gtk_css_array_value_get_n_values (delays) == 1 &&
+      _gtk_css_number_value_get (_gtk_css_array_value_get_nth (durations, 0), 100)
+      + _gtk_css_number_value_get (_gtk_css_array_value_get_nth (delays, transitions[i].index), 100) == 0)
+    return animations;
+
+  transition_infos_set (transitions, gtk_css_style_get_value (base_style, 
GTK_CSS_PROPERTY_TRANSITION_PROPERTY));
 
   for (i = 0; i < GTK_CSS_PROPERTY_N_PROPERTIES; i++)
     {