DisplaySettings: Support disabling the desktop wallpaper

This adds a "None" wallpaper option to allow removing the desktop
wallpaper. This also fixes a longstanding bug that when opening
DisplaySettings without a wallpaper set the first wallpaper would
automatically be selected, marking the settings as modified without the
user having made any changes. (This was due to the model index being
invalid so the first index was automatically selected.)

Author: MacDue

Base/res/icons/32x32/no-wallpaper.png

@@ -50,20 +50,93 @@ BackgroundSettingsWidget::BackgroundSettingsWidget(bool& background_settings_cha
 {
 }
 
+/// A thin wrapper over FileSystemModel for wallpapers in /res/wallpapers. The
+/// only change from a plain FileSystemModel is row zero reserved for "None"
+/// (and this assumes no nested directories).
+class WallpapersModel final : public GUI::Model
+    , GUI::ModelClient {
+public:
+    static NonnullRefPtr<WallpapersModel> create()
+    {
+        return adopt_ref(*new WallpapersModel(GUI::FileSystemModel::create("/res/wallpapers")));
+    }
+
+    virtual ~WallpapersModel() override
+    {
+        m_wallpaper_folder->unregister_client(*this);
+    }
+
+    virtual int row_count(GUI::ModelIndex const&) const override
+    {
+        // Index zero is reserved for "None".
+        return m_wallpaper_folder->row_count() + 1;
+    }
+
+    virtual int column_count(GUI::ModelIndex const&) const override
+    {
+        return 1;
+    }
+
+    virtual GUI::Variant data(GUI::ModelIndex const& index, GUI::ModelRole role) const override
+    {
+        static GUI::Icon no_wallpaper_icon = GUI::Icon::default_icon("no-wallpaper"sv);
+        if (index.row() == 0) {
+            if (role == GUI::ModelRole::Icon)
+                return no_wallpaper_icon;
+            if (role == GUI::ModelRole::Display)
+                return "None";
+            return {};
+        }
+        return m_wallpaper_folder->data(fs_index(index, role), role);
+    }
+
+    AK::ByteString full_path(GUI::ModelIndex const& index)
+    {
+        if (index.row() == 0)
+            return "";
+        return m_wallpaper_folder->full_path(fs_index(index));
+    }
+
+    virtual void model_did_update(unsigned flags) override { did_update(flags); }
+
+    GUI::ModelIndex index_for_path(ByteString path)
+    {
+        auto wallpaper_index = m_wallpaper_folder->index(path, GUI::FileSystemModel::Column::Name);
+        if (wallpaper_index.is_valid())
+            return create_index(wallpaper_index.row() + 1, 0);
+        return create_index(0, 0); // Default to "None".
+    }
+
+private:
+    GUI::ModelIndex fs_index(GUI::ModelIndex const& index, GUI::ModelRole role = GUI::ModelRole::Display) const
+    {
+        VERIFY(index.row() > 0);
+        return m_wallpaper_folder->index(index.row() - 1,
+            role == GUI::ModelRole::Display ? GUI::FileSystemModel::Column::Name : GUI::FileSystemModel::Column::Icon);
+    }
+
+    WallpapersModel(NonnullRefPtr<GUI::FileSystemModel> wallpaper_folder)
+        : m_wallpaper_folder(move(wallpaper_folder))
+    {
+        m_wallpaper_folder->register_client(*this);
+    }
+
+    NonnullRefPtr<GUI::FileSystemModel> m_wallpaper_folder;
+};
+
 ErrorOr<void> BackgroundSettingsWidget::create_frame()
 {
     TRY(load_from_gml(background_settings_gml));
 
     m_monitor_widget = *find_descendant_of_type_named<DisplaySettings::MonitorWidget>("monitor_widget");
 
     m_wallpaper_view = *find_descendant_of_type_named<GUI::IconView>("wallpaper_view");
-    m_wallpaper_view->set_model(GUI::FileSystemModel::create("/res/wallpapers"));
-    m_wallpaper_view->set_model_column(GUI::FileSystemModel::Column::Name);
+    m_wallpaper_view->set_model(WallpapersModel::create());
     m_wallpaper_view->on_selection_change = [this] {
         String path;
         if (!m_wallpaper_view->selection().is_empty()) {
             auto index = m_wallpaper_view->selection().first();
-            auto path_or_error = String::from_byte_string(static_cast<GUI::FileSystemModel*>(m_wallpaper_view->model())->full_path(index));
+            auto path_or_error = String::from_byte_string(static_cast<WallpapersModel*>(m_wallpaper_view->model())->full_path(index));
             if (path_or_error.is_error()) {
                 GUI::MessageBox::show_error(window(), "Unable to load wallpaper"sv);
                 return;
@@ -143,11 +216,9 @@ ErrorOr<void> BackgroundSettingsWidget::load_current_settings()
     auto ws_config = TRY(Core::ConfigFile::open("/etc/WindowServer.ini"));
 
     auto selected_wallpaper = TRY(String::from_byte_string(Config::read_string("WindowManager"sv, "Background"sv, "Wallpaper"sv, ""sv)));
-    if (!selected_wallpaper.is_empty()) {
-        auto index = static_cast<GUI::FileSystemModel*>(m_wallpaper_view->model())->index(selected_wallpaper.to_byte_string(), m_wallpaper_view->model_column());
-        m_wallpaper_view->set_cursor(index, GUI::AbstractView::SelectionUpdate::Set);
-        m_monitor_widget->set_wallpaper(selected_wallpaper);
-    }
+    auto index = static_cast<WallpapersModel*>(m_wallpaper_view->model())->index_for_path(selected_wallpaper.to_byte_string());
+    m_wallpaper_view->set_cursor(index, GUI::AbstractView::SelectionUpdate::Set);
+    m_monitor_widget->set_wallpaper(selected_wallpaper);
 
     auto mode = TRY(String::from_byte_string(ws_config->read_entry("Background", "Mode", "Center")));
     if (!m_modes.contains_slow(mode)) {
@@ -175,18 +246,13 @@ ErrorOr<void> BackgroundSettingsWidget::load_current_settings()
 
 void BackgroundSettingsWidget::apply_settings()
 {
-    auto wallpaper_path_or_empty = m_monitor_widget->wallpaper();
-
-    if (!GUI::Desktop::the().set_wallpaper(m_monitor_widget->wallpaper_bitmap(), wallpaper_path_or_empty)) {
-        if (!wallpaper_path_or_empty.has_value()) {
-            GUI::MessageBox::show_error(window(), "Unable to load wallpaper"sv);
-        } else {
-            auto detailed_error_message = String::formatted("Unable to load file {} as wallpaper", wallpaper_path_or_empty.value());
-            if (!detailed_error_message.is_error())
-                GUI::MessageBox::show_error(window(), detailed_error_message.release_value());
-            else
-                GUI::MessageBox::show_error(window(), "Unable to load wallpaper"sv);
-        }
+    // We need to provide an empty path (not OptionalNone) to set_wallpaper to save a solid color wallpaper.
+    auto wallpaper_path = m_monitor_widget->wallpaper().value_or(""sv);
+    if (!GUI::Desktop::the().set_wallpaper(m_monitor_widget->wallpaper_bitmap(), wallpaper_path)) {
+        if (!wallpaper_path.is_empty())
+            GUI::MessageBox::show_error(window(), MUST(String::formatted("Unable to load file {} as wallpaper", wallpaper_path)));
+        else
+            GUI::MessageBox::show_error(window(), "Unable to set wallpaper"sv);
     }
 
     GUI::Desktop::the().set_background_color(m_color_input->text());

Userland/Applications/DisplaySettings/BackgroundSettingsWidget.cpp

@@ -27,15 +27,10 @@ ErrorOr<NonnullRefPtr<MonitorWidget>> MonitorWidget::try_create()
     return monitor_widget;
 }
 
-bool MonitorWidget::set_wallpaper(String path)
+void MonitorWidget::load_wallpaper(String path)
 {
-    if (!is_different_to_current_wallpaper_path(path))
-        return false;
-
     (void)Threading::BackgroundAction<NonnullRefPtr<Gfx::Bitmap>>::construct(
         [path](auto&) -> ErrorOr<NonnullRefPtr<Gfx::Bitmap>> {
-            if (path.is_empty())
-                return Error::from_errno(ENOENT);
             return Gfx::Bitmap::load_from_file(path);
         },
 
@@ -52,12 +47,21 @@ bool MonitorWidget::set_wallpaper(String path)
         [this, path](Error) -> void {
             m_wallpaper_bitmap = nullptr;
         });
+}
 
-    if (path.is_empty())
+bool MonitorWidget::set_wallpaper(String path)
+{
+    if (!is_different_to_current_wallpaper_path(path))
+        return false;
+    if (path.is_empty()) {
+        m_wallpaper_bitmap = nullptr;
         m_desktop_wallpaper_path = OptionalNone();
-    else
+        m_desktop_dirty = true;
+        update();
+    } else {
+        load_wallpaper(path);
         m_desktop_wallpaper_path = path;
-
+    }
     return true;
 }
 

Userland/Applications/DisplaySettings/MonitorWidget.cpp

@@ -41,6 +41,8 @@ class MonitorWidget final : public GUI::Widget {
 
     virtual void paint_event(GUI::PaintEvent& event) override;
 
+    void load_wallpaper(String path);
+
     Gfx::IntRect m_monitor_rect;
     RefPtr<Gfx::Bitmap> m_monitor_bitmap;
     RefPtr<Gfx::Bitmap> m_desktop_bitmap;
@@ -55,14 +57,9 @@ class MonitorWidget final : public GUI::Widget {
 
     bool is_different_to_current_wallpaper_path(String const& path)
     {
-        if (!m_desktop_wallpaper_path.has_value()) {
-            if (path.is_empty())
-                return false;
-            return true;
-        }
-        if (m_desktop_wallpaper_path.value() == path)
-            return false;
-        return true;
+        if (!path.is_empty())
+            return path != m_desktop_wallpaper_path;
+        return m_desktop_wallpaper_path.has_value();
     }
 };