[sysprof/wip/visualizers] line-visualizer-row: only queue draw when using widget style

[Christian Hergert <chergert src gnome org>]

commit 21ed742215bf89d454a5a66d2fb2083254dd0c0c
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 27 18:30:55 2016 -0700

    line-visualizer-row: only queue draw when using widget style
    
    We can avoid queuing a new draw request if we are not using
    the default styling of the widget in the line drawing.

 lib/sp-line-visualizer-row.c |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)
---
diff --git a/lib/sp-line-visualizer-row.c b/lib/sp-line-visualizer-row.c
index f032e1a..4f3ff25 100644
--- a/lib/sp-line-visualizer-row.c
+++ b/lib/sp-line-visualizer-row.c
@@ -421,12 +421,26 @@ static void
 sp_line_visualizer_row_style_updated (GtkWidget *widget)
 {
   SpLineVisualizerRow *self = (SpLineVisualizerRow *)widget;
+  SpLineVisualizerRowPrivate *priv = sp_line_visualizer_row_get_instance_private (self);
 
   g_assert (SP_IS_LINE_VISUALIZER_ROW (self));
 
   GTK_WIDGET_CLASS (sp_line_visualizer_row_parent_class)->style_updated (widget);
 
-  sp_line_visualizer_row_begin_offscreen_draw (self);
+  /*
+   * Only queue a draw if a line that is drawn relies on the the style context
+   * of the widget (as opposed to a style set manually).
+   */
+  for (guint i = 0; i < priv->lines->len; i++)
+    {
+      const LineInfo *line_info = &g_array_index (priv->lines, LineInfo, i);
+
+      if (line_info->use_default_style)
+        {
+          sp_line_visualizer_row_begin_offscreen_draw (self);
+          break;
+        }
+    }
 }