[gcr] ui: port GcrDisplayItem to use CSS

[Daiki Ueno <dueno src gnome org>]

commit 8ccf5836bdc40ceb26e1c0cd97dc75af1b0d18c9
Author: Dmitry Eremin-Solenikov <dbaryshkov gmail com>
Date:   Sun Jan 12 23:49:06 2020 +0300

    ui: port GcrDisplayItem to use CSS
    
    Since Gtk 3.16 old style functions are deprecated and do not work
    anymore. Update GcrDisplayItem code to use CSS functions (available
    since Gtk 3.0).
    
    Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov gmail com>

 ui/gcr-display-view.c | 55 +++++++++++++++++++++------------------------------
 1 file changed, 22 insertions(+), 33 deletions(-)
---
diff --git a/ui/gcr-display-view.c b/ui/gcr-display-view.c
index abd10fb..d88b74d 100644
--- a/ui/gcr-display-view.c
+++ b/ui/gcr-display-view.c
@@ -245,29 +245,6 @@ on_expander_expanded (GObject *object, GParamSpec *param_spec, gpointer user_dat
        recalculate_and_resize (item->display_view);
 }
 
-static void
-style_display_item (GtkWidget *widget, GcrDisplayItem *item)
-{
-       GtkStyleContext *style;
-       GdkRGBA color;
-
-       style = gtk_widget_get_style_context (GTK_WIDGET (widget));
-       gtk_style_context_save (style);
-
-       gtk_style_context_add_class (style, GTK_STYLE_CLASS_VIEW);
-       gtk_style_context_set_state (style, GTK_STATE_FLAG_NORMAL);
-       gtk_style_context_get_background_color (style,
-                                               gtk_style_context_get_state (style),
-                                               &color);
-
-       gtk_style_context_restore (style);
-
-       color.red = 255;
-       color.green = 0;
-       color.blue = 0;
-       gtk_widget_override_background_color (item->details_widget, GTK_STATE_FLAG_NORMAL, &color);
-}
-
 static GcrDisplayItem*
 create_display_item (GcrDisplayView *self, GcrRenderer *renderer)
 {
@@ -276,6 +253,7 @@ create_display_item (GcrDisplayView *self, GcrRenderer *renderer)
        GtkTextIter iter;
        GtkWidget *widget;
        GtkWidget *label;
+       GtkStyleContext *style;
        gchar *text;
 
        item = g_new0 (GcrDisplayItem, 1);
@@ -334,11 +312,10 @@ create_display_item (GcrDisplayView *self, GcrRenderer *renderer)
        gtk_event_box_set_visible_window (GTK_EVENT_BOX (item->details_widget), FALSE);
        gtk_container_add (GTK_CONTAINER (item->details_widget), widget);
        g_signal_connect (item->details_widget, "realize", G_CALLBACK (on_expander_realize), NULL);
+       style = gtk_widget_get_style_context (GTK_WIDGET (item->details_widget));
+       gtk_style_context_add_class (style, "gcr-red");
        g_object_ref (item->details_widget);
 
-       if (gtk_widget_get_realized (GTK_WIDGET (self)))
-               style_display_item (GTK_WIDGET (self), item);
-
        return item;
 }
 
@@ -654,18 +631,11 @@ static void
 _gcr_display_view_realize (GtkWidget *widget)
 {
        GcrDisplayView *self = GCR_DISPLAY_VIEW (widget);
-       GHashTableIter iter;
        GdkDisplay *display;
-       gpointer value;
 
        if (GTK_WIDGET_CLASS (_gcr_display_view_parent_class)->realize)
                GTK_WIDGET_CLASS (_gcr_display_view_parent_class)->realize (widget);
 
-       /* Set style on all the items */
-       g_hash_table_iter_init (&iter, self->pv->items);
-       while (g_hash_table_iter_next (&iter, NULL, &value))
-               style_display_item (widget, value);
-
        if (!self->pv->cursor) {
                display = gtk_widget_get_display (GTK_WIDGET (self));
                self->pv->cursor = gdk_cursor_new_for_display (display, GDK_ARROW);
@@ -778,6 +748,25 @@ _gcr_display_view_class_init (GcrDisplayViewClass *klass)
        widget_class->draw = _gcr_display_view_draw;
 
        text_view_class->populate_popup = _gcr_display_view_populate_popup;
+
+       /* Load a CSS once */
+       do {
+               GtkCssProvider* provider = gtk_css_provider_new ();
+               GdkDisplay* display = gdk_display_get_default ();
+               GdkScreen* screen = gdk_display_get_default_screen (display);
+               GError *err = NULL;
+
+               gtk_style_context_add_provider_for_screen (screen,
+                                                          GTK_STYLE_PROVIDER(provider),
+                                                          GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+
+               if (!gtk_css_provider_load_from_data (GTK_CSS_PROVIDER(provider),
+                                                     ".gcr-red * { background-color: red; }\n", -1, &err)) {
+                       g_warning ("couldn't load style: %s",
+                                 err && err->message ? err->message : "");
+               }
+               g_object_unref (provider);
+       } while (0);
 }
 
 static void