[gtk+] renderborder: Don't snapshot all-invisible borders

[Timm Bäder <baedert src gnome org>]

commit 09750f9937b981aca8cc72de5f621433fe38c96d
Author: Timm Bäder <mail baedert org>
Date:   Thu Oct 19 15:41:20 2017 +0200

    renderborder: Don't snapshot all-invisible borders
    
    If all of the borders have an alpha of 0, we don't need to snapshot
    anything.

 gtk/gtkrenderborder.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)
---
diff --git a/gtk/gtkrenderborder.c b/gtk/gtkrenderborder.c
index 7d671a2..8e9c059 100644
--- a/gtk/gtkrenderborder.c
+++ b/gtk/gtkrenderborder.c
@@ -952,6 +952,7 @@ gtk_css_style_snapshot_border (GtkCssStyle *style,
       GtkBorderStyle border_style[4];
       GskRoundedRect border_box;
       GdkRGBA colors[4];
+      graphene_simd4f_t alpha_test_vector;
 
       /* Optimize the most common case of "This widget has no border" */
       if (border_width[0] == 0 &&
@@ -960,16 +961,20 @@ gtk_css_style_snapshot_border (GtkCssStyle *style,
           border_width[3] == 0)
         return;
 
-      border_style[0] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_TOP_STYLE));
-      border_style[1] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_RIGHT_STYLE));
-      border_style[2] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_BOTTOM_STYLE));
-      border_style[3] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_LEFT_STYLE));
-
       colors[0] = *_gtk_css_rgba_value_get_rgba (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_TOP_COLOR));
       colors[1] = *_gtk_css_rgba_value_get_rgba (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_RIGHT_COLOR));
       colors[2] = *_gtk_css_rgba_value_get_rgba (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_BOTTOM_COLOR));
       colors[3] = *_gtk_css_rgba_value_get_rgba (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_LEFT_COLOR));
 
+      alpha_test_vector = graphene_simd4f_init (colors[0].alpha, colors[1].alpha, colors[2].alpha, 
colors[3].alpha);
+      if (graphene_simd4f_is_zero4 (alpha_test_vector))
+        return;
+
+      border_style[0] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_TOP_STYLE));
+      border_style[1] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_RIGHT_STYLE));
+      border_style[2] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_BOTTOM_STYLE));
+      border_style[3] = _gtk_css_border_style_value_get (gtk_css_style_get_value (style, 
GTK_CSS_PROPERTY_BORDER_LEFT_STYLE));
+
       gtk_rounded_boxes_init_for_style (&border_box, NULL, NULL, style, 0, 0, width, height);
 
       snapshot_border (snapshot, &border_box, border_width, colors, border_style);