[epiphany] Reader mode: Immediately apply settings when they change

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 7056faabb990ea29520ec02d749bd5166576dff2
Author: Adrian Perez de Castro <aperez igalia com>
Date:   Thu Aug 9 00:17:14 2018 +0300

    Reader mode: Immediately apply settings when they change
    
    This is done by handling te GSettings::changed signal for the settings
    that affect the reader view styling, and running a JavaScript snippet
    which assignd the newly chosen settings to "document.body.className".

 embed/ephy-web-view.c | 74 ++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 56 insertions(+), 18 deletions(-)
---
diff --git a/embed/ephy-web-view.c b/embed/ephy-web-view.c
index 3283e9fdf..6b7fbbc5a 100644
--- a/embed/ephy-web-view.c
+++ b/embed/ephy-web-view.c
@@ -2688,6 +2688,54 @@ script_dialog_cb (WebKitWebView      *web_view,
   return TRUE;
 }
 
+static const char *
+enum_nick (GType enum_type,
+           int   value)
+{
+    GEnumClass *enum_class;
+    const GEnumValue *enum_value;
+    const char *nick = NULL;
+
+    enum_class = g_type_class_ref (enum_type);
+    enum_value = g_enum_get_value (enum_class, value);
+    if (enum_value)
+        nick = enum_value->value_nick;
+
+    g_type_class_unref (enum_class);
+    return nick;
+}
+
+static void
+reader_setting_changed_cb (GSettings   *settings,
+                           gchar       *key,
+                           EphyWebView *web_view)
+{
+  const gchar *font_style;
+  const gchar *color_scheme;
+  gchar *js_snippet;
+
+  if (!web_view->reader_active)
+    return;
+
+  font_style = enum_nick (EPHY_TYPE_PREFS_READER_FONT_STYLE,
+                          g_settings_get_enum (settings,
+                                               EPHY_PREFS_READER_FONT_STYLE));
+  color_scheme = enum_nick (EPHY_TYPE_PREFS_READER_COLOR_SCHEME,
+                            g_settings_get_enum (settings,
+                                                 EPHY_PREFS_READER_COLOR_SCHEME));
+
+  js_snippet = g_strdup_printf ("document.body.className = '%s %s'",
+                                font_style,
+                                color_scheme);
+  webkit_web_view_run_javascript_in_world (WEBKIT_WEB_VIEW (web_view),
+                                           js_snippet,
+                                           ephy_embed_shell_get_guid (ephy_embed_shell_get_default ()),
+                                           NULL,
+                                           NULL,
+                                           NULL);
+  g_free (js_snippet);
+}
+
 static void
 ephy_web_view_init (EphyWebView *web_view)
 {
@@ -2701,6 +2749,14 @@ ephy_web_view_init (EphyWebView *web_view)
   web_view->history_service = ephy_embed_shell_get_global_history_service (ephy_embed_shell_get_default ());
   web_view->history_service_cancellable = g_cancellable_new ();
 
+  g_signal_connect (EPHY_SETTINGS_READER, "changed::" EPHY_PREFS_READER_FONT_STYLE,
+                    G_CALLBACK (reader_setting_changed_cb),
+                    web_view);
+
+  g_signal_connect (EPHY_SETTINGS_READER, "changed::" EPHY_PREFS_READER_COLOR_SCHEME,
+                    G_CALLBACK (reader_setting_changed_cb),
+                    web_view);
+
   g_signal_connect (web_view, "decide-policy",
                     G_CALLBACK (decide_policy_cb),
                     NULL);
@@ -3631,24 +3687,6 @@ ephy_web_view_set_visit_type (EphyWebView *view, EphyHistoryPageVisitType visit_
 }
 
 
-static const char *
-enum_nick (GType enum_type,
-           int   value)
-{
-    GEnumClass *enum_class;
-    const GEnumValue *enum_value;
-    const char *nick = NULL;
-
-    enum_class = g_type_class_ref (enum_type);
-    enum_value = g_enum_get_value (enum_class, value);
-    if (enum_value)
-        nick = enum_value->value_nick;
-
-    g_type_class_unref (enum_class);
-    return nick;
-}
-
-
 /**
  * ephy_web_view_toggle_reader_mode:
  * @view: an #EphyWebView