[gnome-shell] main: Add support for -high-contrast theme variants

[Florian Müllner <fmuellner src gnome org>]

commit f4cc3327e8694764d339abe6af2e757620409d5f
Author: Florian Müllner <fmuellner gnome org>
Date:   Sat Nov 29 13:37:19 2014 +0000

    main: Add support for -high-contrast theme variants
    
    While the default Shell style is fairly decent with regard to
    accessibility requirements, having the ability to tweak certain
    aspects where the regular style works less well is still useful.
    For this purpose, try to load a -high-contrast theme variant of
    the default stylesheet when a high-contrast theme is requested
    (as determined by the GTK+ theme name).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=740447

 js/ui/main.js |   30 +++++++++++++++++++++++-------
 1 files changed, 23 insertions(+), 7 deletions(-)
---
diff --git a/js/ui/main.js b/js/ui/main.js
index 36d7591..0b22a36 100644
--- a/js/ui/main.js
+++ b/js/ui/main.js
@@ -4,6 +4,7 @@ const Clutter = imports.gi.Clutter;
 const Gdk = imports.gi.Gdk;
 const Gio = imports.gi.Gio;
 const GLib = imports.gi.GLib;
+const Gtk = imports.gi.Gtk;
 const Lang = imports.lang;
 const Mainloop = imports.mainloop;
 const Meta = imports.gi.Meta;
@@ -75,7 +76,8 @@ let _cssStylesheet = null;
 let _a11ySettings = null;
 
 function _sessionUpdated() {
-    _loadDefaultStylesheet();
+    if (sessionMode.isPrimary)
+        _loadDefaultStylesheet();
 
     wm.setCustomKeybindingHandler('panel-main-menu',
                                   Shell.KeyBindingMode.NORMAL |
@@ -109,6 +111,8 @@ function start() {
 
     sessionMode = new SessionMode.SessionMode();
     sessionMode.connect('updated', _sessionUpdated);
+    Gtk.Settings.get_default().connect('notify::gtk-theme-name',
+                                       _loadDefaultStylesheet);
     _initializeUI();
 
     shellDBusService = new ShellDBus.GnomeShell();
@@ -225,24 +229,36 @@ function _initializeUI() {
     });
 }
 
-function _getDefaultStylesheet() {
+function _getStylesheet(name) {
     let stylesheet;
 
-    stylesheet = Gio.File.new_for_uri('resource:///org/gnome/shell/theme/' + sessionMode.stylesheetName);
+    stylesheet = Gio.File.new_for_uri('resource:///org/gnome/shell/theme/' + name);
     if (stylesheet.query_exists(null))
         return stylesheet;
 
-    stylesheet = Gio.File.new_for_path(global.datadir + '/theme/' + sessionMode.stylesheetName);
+    stylesheet = Gio.File.new_for_path(global.datadir + '/theme/' + name);
     if (stylesheet.query_exists(null))
         return stylesheet;
 
     return null;
 }
 
-function _loadDefaultStylesheet() {
-    if (!sessionMode.isPrimary)
-        return;
+function _getDefaultStylesheet() {
+    let stylesheet = null;
+    let name = sessionMode.stylesheetName;
 
+    // Look for a high-contrast variant first when using GTK+'s HighContrast
+    // theme
+    if (Gtk.Settings.get_default().gtk_theme_name == 'HighContrast')
+        stylesheet = _getStylesheet(name.replace('.css', '-high-contrast.css'));
+
+    if (stylesheet == null)
+        stylesheet = _getStylesheet(sessionMode.stylesheetName);
+
+    return stylesheet;
+}
+
+function _loadDefaultStylesheet() {
     let stylesheet = _getDefaultStylesheet();
     if (_defaultCssStylesheet && _defaultCssStylesheet.equal(stylesheet))
         return;