[tepl] GotoLineBar: add a pinch of CSS

[Sébastien Wilmet <swilmet src gnome org>]

commit 6930c147c70f9737b0dcf44c9cdaae17fc0b597f
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed May 6 20:14:19 2020 +0200

    GotoLineBar: add a pinch of CSS

 tepl/tepl-goto-line-bar.c | 38 ++++++++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)
---
diff --git a/tepl/tepl-goto-line-bar.c b/tepl/tepl-goto-line-bar.c
index f5aefd1..e1d8416 100644
--- a/tepl/tepl-goto-line-bar.c
+++ b/tepl/tepl-goto-line-bar.c
@@ -56,6 +56,8 @@ tepl_goto_line_bar_class_init (TeplGotoLineBarClass *klass)
        GObjectClass *object_class = G_OBJECT_CLASS (klass);
 
        object_class->dispose = tepl_goto_line_bar_dispose;
+
+       gtk_widget_class_set_css_name (GTK_WIDGET_CLASS (klass), "TeplGotoLineBar");
 }
 
 static void
@@ -188,6 +190,36 @@ bar_hide_cb (TeplGotoLineBar *bar,
        create_entry (bar);
 }
 
+static void
+apply_style (TeplGotoLineBar *bar)
+{
+       GtkStyleContext *style_context;
+       const gchar *css;
+       GtkCssProvider *css_provider;
+
+       style_context = gtk_widget_get_style_context (GTK_WIDGET (bar));
+       gtk_style_context_add_class (style_context, GTK_STYLE_CLASS_FRAME);
+
+       css = "TeplGotoLineBar {\n"
+             "  padding-left: 6px;\n"
+             "  padding-right: 4px;\n"
+             "  padding-top: 3px;\n"
+             "  padding-bottom: 3px;\n"
+             "\n"
+             "  border-bottom: none;\n"
+             "  border-left: none;\n"
+             "  border-right: none;\n"
+             "}\n";
+
+       css_provider = gtk_css_provider_new ();
+       gtk_css_provider_load_from_data (css_provider, css, -1, NULL);
+       gtk_style_context_add_provider (style_context,
+                                       GTK_STYLE_PROVIDER (css_provider),
+                                       /* Priority "library". */
+                                       GTK_STYLE_PROVIDER_PRIORITY_APPLICATION - 1);
+       g_object_unref (css_provider);
+}
+
 static void
 tepl_goto_line_bar_init (TeplGotoLineBar *bar)
 {
@@ -196,11 +228,9 @@ tepl_goto_line_bar_init (TeplGotoLineBar *bar)
 
        bar->priv = tepl_goto_line_bar_get_instance_private (bar);
 
+       apply_style (bar);
+
        gtk_grid_set_column_spacing (GTK_GRID (bar), 6);
-       gtk_widget_set_margin_start (GTK_WIDGET (bar), 6);
-       gtk_widget_set_margin_end (GTK_WIDGET (bar), 4);
-       gtk_widget_set_margin_top (GTK_WIDGET (bar), 3);
-       gtk_widget_set_margin_bottom (GTK_WIDGET (bar), 3);
 
        label = gtk_label_new (_("Go to line:"));
        gtk_widget_show (label);