[gtk+] notebook: Improve the style of the default arrows

[William Jon McCann <mccann src gnome org>]

commit 8dd100d9b0539bc6bb28c95bdd8e7d5329faf42d
Author: William Jon McCann <william jon mccann gmail com>
Date:   Mon Aug 5 16:37:39 2013 +0200

    notebook: Improve the style of the default arrows
    
    https://bugzilla.gnome.org/show_bug.cgi?id=707920

 gtk/gtkthemingengine.c |   55 +++++++++++++++++++----------------------------
 1 files changed, 22 insertions(+), 33 deletions(-)
---
diff --git a/gtk/gtkthemingengine.c b/gtk/gtkthemingengine.c
index ee9a1a4..18f7f74 100644
--- a/gtk/gtkthemingengine.c
+++ b/gtk/gtkthemingengine.c
@@ -1263,26 +1263,6 @@ gtk_theming_engine_render_option (GtkThemingEngine *engine,
 }
 
 static void
-add_path_arrow (cairo_t *cr,
-                gdouble  angle,
-                gdouble  x,
-                gdouble  y,
-                gdouble  size)
-{
-  cairo_save (cr);
-
-  cairo_translate (cr, x + (size / 2), y + (size / 2));
-  cairo_rotate (cr, angle);
-
-  cairo_move_to (cr, 0, - (size / 4));
-  cairo_line_to (cr, - (size / 2), (size / 4));
-  cairo_line_to (cr, (size / 2), (size / 4));
-  cairo_close_path (cr);
-
-  cairo_restore (cr);
-}
-
-static void
 gtk_theming_engine_render_arrow (GtkThemingEngine *engine,
                                  cairo_t          *cr,
                                  gdouble           angle,
@@ -1290,24 +1270,33 @@ gtk_theming_engine_render_arrow (GtkThemingEngine *engine,
                                  gdouble           y,
                                  gdouble           size)
 {
-  GtkStateFlags flags;
-  GdkRGBA fg_color;
+  double line_width;
+  GtkStateFlags state;
+  GdkRGBA color;
 
   cairo_save (cr);
 
-  flags = gtk_theming_engine_get_state (engine);
-  gtk_theming_engine_get_color (engine, flags, &fg_color);
+  line_width = size / 3.0 / sqrt (2);
+  cairo_set_line_width (cr, line_width);
+  cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
+  cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
 
-  if (flags & GTK_STATE_FLAG_INSENSITIVE)
-    {
-      add_path_arrow (cr, angle, x + 1, y + 1, size);
-      cairo_set_source_rgb (cr, 1, 1, 1);
-      cairo_fill (cr);
-    }
+  cairo_translate (cr, x + size / 2.0, y + size / 2.0);
+  cairo_rotate (cr, angle - G_PI_2);
+  cairo_translate (cr, size / 4.0, 0);
 
-  add_path_arrow (cr, angle, x, y, size);
-  gdk_cairo_set_source_rgba (cr, &fg_color);
-  cairo_fill (cr);
+  cairo_scale (cr,
+               (size / (size + line_width)),
+               (size / (size + line_width)));
+
+  cairo_move_to (cr, -size / 2.0, -size / 2.0);
+  cairo_rel_line_to (cr, size / 2.0, size / 2.0);
+  cairo_rel_line_to (cr, - size / 2.0, size / 2.0);
+
+  state = gtk_theming_engine_get_state (engine);
+  gtk_theming_engine_get_color (engine, state, &color);
+  gdk_cairo_set_source_rgba (cr, &color);
+  cairo_stroke (cr);
 
   cairo_restore (cr);
 }