nemo-desktop: Allow adjustment to label shadow.

Add two settings:
- desktop-text-shadow: Three levels of shadow (normal, darker,
  darkest) - normal being the traditional amount.
- desktop-text-shadow-use-theme: If true, and if the theme supports
  it, allow the GTK theme to control desktop style, including text
  shadow.

Nemo has always checked for theme support at startup and during
theme changes, to ensure custom widgets/features worked correctly
for users (such as inactive-pane shading). We add another check for
'nemo-desktop' there. If the theme lacks any support, nemo provides
it like before, using the shadow-level setting.

Author: mtwebster

gresources/nemo-desktop-preferences.glade

@@ -1,4 +1,5 @@
-/* Desktop text stuff */
+/* Desktop window structure — always applied regardless of theme.
+ * The desktop window must be transparent so the wallpaper shows through. */
 
 .nemo-window.nemo-desktop-window notebook,
 .nemo-window.nemo-desktop-window paned {
@@ -11,37 +12,17 @@
     box-shadow: none;
 }
 
-NemoDesktopWindow GtkPaned {
-    background-color: transparent;
-}
-
 .nemo-canvas-item {
     border-radius: 3px;
 }
 
+/* Custom widget property — controls nemo behavior, not appearance. */
 .nemo-desktop {
     -NemoIconContainer-activate-prelight-icon-label: true;
 }
 
-.nemo-desktop.nemo-canvas-item {
-    color: #eeeeee;
-    text-shadow: 1px 1px alpha(black, 0.8);
-}
-
-.nemo-desktop.nemo-canvas-item:hover {
-    background-color: alpha(black, 0.5);
-    background-image: none;
-    text-shadow: none;
-}
-
-.nemo-desktop.nemo-canvas-item:selected {
-    background-color: alpha(@theme_selected_bg_color, 0.8);
-    background-image: none;
-    text-shadow: none;
-    color: #f5f5f5;
-}
-
-/* EelEditableLabel (icon labels) */
+/* EelEditableLabel (inline rename entry on desktop).
+ * Always applied so the rename box stays legible over any wallpaper. */
 .nemo-desktop.view .entry,
 .nemo-desktop.view .entry:active,
 .nemo-desktop.view .entry:focus,

gresources/nemo-style-application.css

@@ -0,0 +1,45 @@
+/* Desktop icon label text shadows.
+ *
+ * Nemo applies one of these classes (shadow-normal / shadow-darker /
+ * shadow-darkest) to the icon container based on the user's preference.
+ * If "Use GTK theme" is enabled and the current theme provides its own
+ * .nemo-desktop styling, this entire stylesheet is not loaded — the
+ * theme controls text appearance directly.
+ */
+
+/* Shadow variant: Normal (traditional nemo default) */
+.nemo-desktop.nemo-canvas-item.shadow-normal {
+    color: #eeeeee;
+    text-shadow: 1px 1px alpha(black, 0.8);
+}
+
+/* Shadow variant: Darker */
+.nemo-desktop.nemo-canvas-item.shadow-darker {
+    color: #eeeeee;
+    text-shadow: 1px 1px black;
+}
+
+/* Shadow variant: Darkest */
+.nemo-desktop.nemo-canvas-item.shadow-darkest {
+    color: #eeeeee;
+    text-shadow: 1px 1px black, 1px 0px alpha(black, 0.6), 0px 1px alpha(black, 0.6);
+}
+
+/* Hover for shadow modes */
+.nemo-desktop.nemo-canvas-item.shadow-normal:hover,
+.nemo-desktop.nemo-canvas-item.shadow-darker:hover,
+.nemo-desktop.nemo-canvas-item.shadow-darkest:hover {
+    background-color: alpha(black, 0.5);
+    background-image: none;
+    text-shadow: none;
+}
+
+/* Selected for shadow modes */
+.nemo-desktop.nemo-canvas-item.shadow-normal:selected,
+.nemo-desktop.nemo-canvas-item.shadow-darker:selected,
+.nemo-desktop.nemo-canvas-item.shadow-darkest:selected {
+    background-color: alpha(@theme_selected_bg_color, 0.8);
+    background-image: none;
+    text-shadow: none;
+    color: #f5f5f5;
+}

gresources/nemo-style-desktop.css

@@ -26,5 +26,6 @@
     <file>nemo-style-fallback.css</file>
     <file>nemo-style-fallback-mandatory.css</file>
     <file>nemo-style-application.css</file>
+    <file>nemo-style-desktop.css</file>
   </gresource>
 </gresources>

gresources/nemo.gresource.xml

@@ -3,12 +3,32 @@
 #include <gtk/gtk.h>
 #include <gdk/gdk.h>
 #include <math.h>
+#include <glib/gi18n.h>
 #include "nemo-desktop-preferences.h"
 
+#define NUM_SHADOW_OPTIONS 3
+
+static const gchar *shadow_options[NUM_SHADOW_OPTIONS] = {
+    "normal",
+    "darker",
+    "darkest",
+};
+
+static const gchar *preview_bg_css =
+    ".shadow-preview-bg {"
+    "  background-image: linear-gradient(to bottom, #7ba4d4, #d4e6f7);"
+    "}";
+
 typedef struct
 {
     GtkBuilder *builder;
     GSettings *desktop_settings;
+    GtkCssProvider *desktop_css_provider;
+    GtkCssProvider *preview_bg_provider;
+    GtkWidget *shadow_radios[NUM_SHADOW_OPTIONS];
+    GtkWidget *shadow_labels[NUM_SHADOW_OPTIONS];
+    gulong shadow_setting_handler;
+    gulong font_changed_handler;
 } NemoDesktopPreferencesPrivate;
 
 struct _NemoDesktopPreferences
@@ -43,6 +63,141 @@ bind_builder_string_combo (GtkBuilder *builder,
                      "active-id", G_SETTINGS_BIND_DEFAULT);
 }
 
+static void
+update_preview_fonts (NemoDesktopPreferencesPrivate *priv)
+{
+    gchar *font_str;
+    PangoFontDescription *font_desc;
+    gint i;
+
+    font_str = g_settings_get_string (priv->desktop_settings, "font");
+    font_desc = pango_font_description_from_string (font_str);
+    g_free (font_str);
+
+    for (i = 0; i < NUM_SHADOW_OPTIONS; i++) {
+        PangoAttrList *attrs = pango_attr_list_new ();
+        pango_attr_list_insert (attrs, pango_attr_font_desc_new (font_desc));
+        gtk_label_set_attributes (GTK_LABEL (priv->shadow_labels[i]), attrs);
+        pango_attr_list_unref (attrs);
+    }
+
+    pango_font_description_free (font_desc);
+}
+
+static void
+on_shadow_button_toggled (GtkToggleButton *button, gpointer user_data)
+{
+    NemoDesktopPreferencesPrivate *priv = user_data;
+    const gchar *id;
+
+    if (!gtk_toggle_button_get_active (button))
+        return;
+
+    id = g_object_get_data (G_OBJECT (button), "shadow-id");
+    g_settings_set_string (priv->desktop_settings, "desktop-text-shadow", id);
+}
+
+static void
+on_shadow_setting_changed (GSettings *settings,
+                           const gchar *key,
+                           gpointer user_data)
+{
+    NemoDesktopPreferences *preferences = NEMO_DESKTOP_PREFERENCES (user_data);
+    NemoDesktopPreferencesPrivate *priv = preferences->priv;
+    gchar *current;
+    gint i;
+
+    current = g_settings_get_string (priv->desktop_settings, "desktop-text-shadow");
+
+    for (i = 0; i < NUM_SHADOW_OPTIONS; i++) {
+        if (g_strcmp0 (current, shadow_options[i]) == 0) {
+            g_signal_handlers_block_by_func (priv->shadow_radios[i],
+                                             on_shadow_button_toggled, priv);
+            gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (priv->shadow_radios[i]), TRUE);
+            g_signal_handlers_unblock_by_func (priv->shadow_radios[i],
+                                               on_shadow_button_toggled, priv);
+            break;
+        }
+    }
+
+    g_free (current);
+}
+
+static void
+on_desktop_font_changed (GSettings *settings,
+                         const gchar *key,
+                         gpointer user_data)
+{
+    NemoDesktopPreferences *preferences = NEMO_DESKTOP_PREFERENCES (user_data);
+    update_preview_fonts (preferences->priv);
+}
+
+static void
+add_provider_to_widget (GtkWidget *widget, GtkCssProvider *provider)
+{
+    gtk_style_context_add_provider (gtk_widget_get_style_context (widget),
+                                   GTK_STYLE_PROVIDER (provider),
+                                   GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+}
+
+static void
+setup_shadow_preview_buttons (NemoDesktopPreferences *preferences)
+{
+    NemoDesktopPreferencesPrivate *priv = preferences->priv;
+    gchar *current;
+    gint i;
+
+    priv->desktop_css_provider = gtk_css_provider_new ();
+    gtk_css_provider_load_from_resource (priv->desktop_css_provider,
+                                         "/org/nemo/nemo-style-desktop.css");
+
+    priv->preview_bg_provider = gtk_css_provider_new ();
+    gtk_css_provider_load_from_data (priv->preview_bg_provider, preview_bg_css, -1, NULL);
+
+    current = g_settings_get_string (priv->desktop_settings, "desktop-text-shadow");
+
+    for (i = 0; i < NUM_SHADOW_OPTIONS; i++) {
+        gchar *name;
+
+        name = g_strdup_printf ("shadow_radio_%s", shadow_options[i]);
+        priv->shadow_radios[i] = GTK_WIDGET (gtk_builder_get_object (priv->builder, name));
+        g_free (name);
+
+        name = g_strdup_printf ("shadow_frame_%s", shadow_options[i]);
+        add_provider_to_widget (GTK_WIDGET (gtk_builder_get_object (priv->builder, name)),
+                                priv->preview_bg_provider);
+        g_free (name);
+
+        name = g_strdup_printf ("shadow_label_%s", shadow_options[i]);
+        priv->shadow_labels[i] = GTK_WIDGET (gtk_builder_get_object (priv->builder, name));
+        g_free (name);
+
+        add_provider_to_widget (priv->shadow_labels[i], priv->desktop_css_provider);
+
+        g_object_set_data (G_OBJECT (priv->shadow_radios[i]), "shadow-id",
+                           (gpointer) shadow_options[i]);
+
+        g_signal_connect (priv->shadow_radios[i], "toggled",
+                          G_CALLBACK (on_shadow_button_toggled), priv);
+
+        if (g_strcmp0 (current, shadow_options[i]) == 0) {
+            gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (priv->shadow_radios[i]), TRUE);
+        }
+    }
+
+    g_free (current);
+
+    update_preview_fonts (priv);
+
+    priv->shadow_setting_handler =
+        g_signal_connect (priv->desktop_settings, "changed::desktop-text-shadow",
+                          G_CALLBACK (on_shadow_setting_changed), preferences);
+
+    priv->font_changed_handler =
+        g_signal_connect (priv->desktop_settings, "changed::font",
+                          G_CALLBACK (on_desktop_font_changed), preferences);
+}
+
 static void
 nemo_desktop_preferences_init (NemoDesktopPreferences *preferences)
 {
@@ -96,16 +251,37 @@ nemo_desktop_preferences_init (NemoDesktopPreferences *preferences)
                        "orphan_switch",
                        "show-orphaned-desktop-icons");
 
+    bind_builder_bool (priv->builder,
+                       priv->desktop_settings,
+                       "use_theme_switch",
+                       "desktop-text-shadow-use-theme");
+
+    setup_shadow_preview_buttons (preferences);
+
     gtk_widget_show_all (GTK_WIDGET (preferences));
 }
 
 static void
 nemo_desktop_preferences_dispose (GObject *object)
 {
     NemoDesktopPreferences *preferences = NEMO_DESKTOP_PREFERENCES (object);
+    NemoDesktopPreferencesPrivate *priv = preferences->priv;
+
+    if (priv->desktop_settings != NULL) {
+        if (priv->shadow_setting_handler > 0) {
+            g_signal_handler_disconnect (priv->desktop_settings, priv->shadow_setting_handler);
+            priv->shadow_setting_handler = 0;
+        }
+        if (priv->font_changed_handler > 0) {
+            g_signal_handler_disconnect (priv->desktop_settings, priv->font_changed_handler);
+            priv->font_changed_handler = 0;
+        }
+    }
 
-    g_clear_object (&preferences->priv->builder);
-    g_clear_object (&preferences->priv->desktop_settings);
+    g_clear_object (&priv->desktop_css_provider);
+    g_clear_object (&priv->preview_bg_provider);
+    g_clear_object (&priv->builder);
+    g_clear_object (&priv->desktop_settings);
 
     G_OBJECT_CLASS (nemo_desktop_preferences_parent_class)->dispose (object);
 }

libnemo-extension/nemo-desktop-preferences.c

@@ -226,6 +226,8 @@ typedef enum
 #define NEMO_PREFERENCES_DESKTOP_VOLUMES_VISIBLE	   "volumes-visible"
 #define NEMO_PREFERENCES_DESKTOP_NETWORK_VISIBLE       "network-icon-visible"
 #define NEMO_PREFERENCES_DESKTOP_BACKGROUND_FADE       "background-fade"
+#define NEMO_PREFERENCES_DESKTOP_TEXT_SHADOW           "desktop-text-shadow"
+#define NEMO_PREFERENCES_DESKTOP_TEXT_SHADOW_USE_THEME "desktop-text-shadow-use-theme"
 #define NEMO_PREFERENCES_DESKTOP_IGNORED_DESKTOP_HANDLERS "ignored-desktop-handlers"
 
 /* bulk rename utility */

libnemo-private/nemo-global-preferences.h

@@ -7152,6 +7152,38 @@ nemo_icon_container_get_is_desktop (NemoIconContainer *container)
 	return container->details->is_desktop;
 }
 
+static const gchar *shadow_class_names[] = {
+    "shadow-normal",
+    "shadow-darker",
+    "shadow-darkest"
+};
+
+static void
+update_desktop_shadow_class (NemoIconContainer *container)
+{
+    GtkStyleContext *context;
+    gchar *setting, *class_name;
+    gint i;
+
+    context = gtk_widget_get_style_context (GTK_WIDGET (container));
+
+    for (i = 0; i < G_N_ELEMENTS (shadow_class_names); i++) {
+        gtk_style_context_remove_class (context, shadow_class_names[i]);
+    }
+
+    /* The class is always applied. When the user has opted into theme-driven
+     * styling and the theme supports it, nemo-theme-utils skips loading the
+     * shadow stylesheet, so the class simply matches no rules. */
+    setting = g_settings_get_string (nemo_desktop_preferences,
+                                     NEMO_PREFERENCES_DESKTOP_TEXT_SHADOW);
+    class_name = g_strdup_printf ("shadow-%s", setting);
+    gtk_style_context_add_class (context, class_name);
+    g_free (class_name);
+    g_free (setting);
+
+    gtk_widget_queue_draw (GTK_WIDGET (container));
+}
+
 void
 nemo_icon_container_set_is_desktop (NemoIconContainer *container,
 					   gboolean is_desktop)
@@ -7166,17 +7198,27 @@ nemo_icon_container_set_is_desktop (NemoIconContainer *container,
     g_signal_handlers_disconnect_by_func (nemo_desktop_preferences,
                                           text_ellipsis_limit_changed_container_callback,
                                           container);
+    g_signal_handlers_disconnect_by_func (nemo_desktop_preferences,
+                                          update_desktop_shadow_class,
+                                          container);
 
     if (is_desktop) {
         GtkStyleContext *context;
 
         context = gtk_widget_get_style_context (GTK_WIDGET (container));
         gtk_style_context_add_class (context, "nemo-desktop");
 
+        update_desktop_shadow_class (container);
+
         g_signal_connect_swapped (nemo_desktop_preferences,
                                   "changed::" NEMO_PREFERENCES_DESKTOP_TEXT_ELLIPSIS_LIMIT,
                                   G_CALLBACK (text_ellipsis_limit_changed_container_callback),
                                   container);
+
+        g_signal_connect_swapped (nemo_desktop_preferences,
+                                  "changed::" NEMO_PREFERENCES_DESKTOP_TEXT_SHADOW,
+                                  G_CALLBACK (update_desktop_shadow_class),
+                                  container);
     } else {
         g_signal_connect_swapped (nemo_icon_view_preferences,
                                   "changed::" NEMO_PREFERENCES_ICON_VIEW_TEXT_ELLIPSIS_LIMIT,