status-notifier: Fix elements display on GTK < 3.20

On GTK 3.20 onwards, themes are expected to use CSS names rather than
widget class names, and apparently CSS names are not inherited.  So, a
derived widget altering its CSS name won't be styled as its parent
classes.

Thus, SnItem setting the CSS name "sn-item" avoids being styled as a
"button".  But on older GTK versions, the widget class being used makes
this change ineffective.
Fix that by introducing a custom derived button that doesn't draw the
unwanted parts.

5 files changed, 241 insertions, 3 deletions

diff --git a/applets/notification_area/status-notifier/Makefile.am b/applets/notification_area/status-notifier/Makefile.am
index 9bbb4134..6eab62ee 100644
--- a/applets/notification_area/status-notifier/Makefile.am
+++ b/applets/notification_area/status-notifier/Makefile.am
@@ -22,6 +22,8 @@ libstatus_notifier_la_SOURCES =		\
 	sn-dbus-menu.h			\
 	sn-dbus-menu-item.c		\
 	sn-dbus-menu-item.h		\
+	sn-flat-button.c		\
+	sn-flat-button.h		\
 	sn-host-v0.c			\
 	sn-host-v0.h			\
 	sn-image-menu-item.c		\
diff --git a/applets/notification_area/status-notifier/sn-flat-button.c b/applets/notification_area/status-notifier/sn-flat-button.c
new file mode 100644
index 00000000..d920dadf
--- /dev/null
+++ b/applets/notification_area/status-notifier/sn-flat-button.c
@@ -0,0 +1,174 @@
+/*
+ * Copyright (C) 2017 Colomban Wendling <[email protected]>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * A GtkButton that doesn't draw anything specific but the focus, and pass
+ * all drawing and sizing requests to its child.
+ */
+
+#define SN_FLAT_BUTTON_C
+
+#include <gtk/gtk.h>
+
+#include "sn-flat-button.h"
+
+G_DEFINE_TYPE (SnFlatButton,
+               sn_flat_button,
+               GTK_TYPE_BUTTON)
+
+static gboolean
+sn_flat_button_draw (GtkWidget *widget,
+                     cairo_t   *cr)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    gtk_container_propagate_draw (GTK_CONTAINER (widget), child, cr);
+
+  if (gtk_widget_is_drawable (widget) && gtk_widget_has_focus (widget))
+    {
+      GtkStyleContext *context = gtk_widget_get_style_context (widget);
+      gdouble x1, y1, x2, y2;
+
+      cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
+      gtk_render_focus (context, cr, x1, y1, x2 - x1, y2 - y1);
+    }
+
+  return child != NULL;
+}
+
+static void
+sn_flat_button_size_allocate (GtkWidget     *widget,
+                              GtkAllocation *allocation)
+{
+  GtkWidget *child;
+
+  GTK_WIDGET_CLASS (sn_flat_button_parent_class)->size_allocate (widget,
+                                                                 allocation);
+
+  child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child && gtk_widget_get_visible (child))
+    gtk_widget_size_allocate (child, allocation);
+}
+
+static GtkSizeRequestMode
+sn_flat_button_get_request_mode (GtkWidget *widget)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    return gtk_widget_get_request_mode (child);
+  else
+    return GTK_WIDGET_CLASS (sn_flat_button_parent_class)->get_request_mode (widget);
+}
+
+static void
+sn_flat_button_get_preferred_height (GtkWidget *widget,
+                                     gint      *min,
+                                     gint      *nat)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    gtk_widget_get_preferred_height (child, min, nat);
+  else
+    GTK_WIDGET_CLASS (sn_flat_button_parent_class)->get_preferred_height (widget, min, nat);
+}
+
+static void
+sn_flat_button_get_preferred_width (GtkWidget *widget,
+                                    gint      *min,
+                                    gint      *nat)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    gtk_widget_get_preferred_width (child, min, nat);
+  else
+    GTK_WIDGET_CLASS (sn_flat_button_parent_class)->get_preferred_width (widget, min, nat);
+}
+
+static void
+sn_flat_button_get_preferred_height_for_width (GtkWidget *widget,
+                                               gint       width,
+                                               gint      *min,
+                                               gint      *nat)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    gtk_widget_get_preferred_height_for_width (child, width, min, nat);
+  else
+    GTK_WIDGET_CLASS (sn_flat_button_parent_class)->get_preferred_height_for_width (widget, width, min, nat);
+}
+
+static void
+sn_flat_button_get_preferred_width_for_height (GtkWidget *widget,
+                                               gint       height,
+                                               gint      *min,
+                                               gint      *nat)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    gtk_widget_get_preferred_width_for_height (child, height, min, nat);
+  else
+    GTK_WIDGET_CLASS (sn_flat_button_parent_class)->get_preferred_width_for_height (widget, height, min, nat);
+}
+
+static void
+sn_flat_button_get_preferred_height_and_baseline_for_width (GtkWidget *widget,
+                                                            gint       width,
+                                                            gint      *min,
+                                                            gint      *nat,
+                                                            gint      *min_baseline,
+                                                            gint      *nat_baseline)
+{
+  GtkWidget *child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child)
+    gtk_widget_get_preferred_height_and_baseline_for_width (child, width, min, nat,
+                                                            min_baseline, nat_baseline);
+  else
+    GTK_WIDGET_CLASS (sn_flat_button_parent_class)->get_preferred_height_and_baseline_for_width (widget, width,
+                                                                                                 min, nat,
+                                                                                                 min_baseline, nat_baseline);
+}
+
+static void
+sn_flat_button_class_init (SnFlatButtonClass *klass)
+{
+  GtkWidgetClass *widget_class;
+
+  widget_class = GTK_WIDGET_CLASS (klass);
+
+  widget_class->draw = sn_flat_button_draw;
+  widget_class->size_allocate = sn_flat_button_size_allocate;
+  widget_class->get_request_mode = sn_flat_button_get_request_mode;
+  widget_class->get_preferred_height = sn_flat_button_get_preferred_height;
+  widget_class->get_preferred_height_for_width = sn_flat_button_get_preferred_height_for_width;
+  widget_class->get_preferred_height_and_baseline_for_width = sn_flat_button_get_preferred_height_and_baseline_for_width;
+  widget_class->get_preferred_width = sn_flat_button_get_preferred_width;
+  widget_class->get_preferred_width_for_height = sn_flat_button_get_preferred_width_for_height;
+}
+
+static void
+sn_flat_button_init (SnFlatButton *self)
+{
+  gtk_button_set_relief (GTK_BUTTON (self), GTK_RELIEF_NONE);
+}
diff --git a/applets/notification_area/status-notifier/sn-flat-button.h b/applets/notification_area/status-notifier/sn-flat-button.h
new file mode 100644
index 00000000..1a93d30f
--- /dev/null
+++ b/applets/notification_area/status-notifier/sn-flat-button.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2017 Colomban Wendling <[email protected]>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SN_FLAT_BUTTON_H
+#define SN_FLAT_BUTTON_H
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define SN_TYPE_FLAT_BUTTON            (sn_flat_button_get_type ())
+#define SN_FLAT_BUTTON(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), SN_TYPE_FLAT_BUTTON, SnFlatButton))
+#define SN_FLAT_BUTTON_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), SN_TYPE_FLAT_BUTTON, SnFlatButtonClass))
+#define SN_IS_FLAT_BUTTON(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), SN_TYPE_FLAT_BUTTON))
+#define SN_IS_FLAT_BUTTON_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), SN_TYPE_FLAT_BUTTON))
+#define SN_FLAT_BUTTON_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), SN_TYPE_FLAT_BUTTON, SnFlatButtonClass))
+
+typedef struct _SnFlatButton        SnFlatButton;
+typedef struct _SnFlatButtonPrivate SnFlatButtonPrivate;
+typedef struct _SnFlatButtonClass   SnFlatButtonClass;
+
+struct _SnFlatButton
+{
+  GtkButton parent_instance;
+
+  SnFlatButtonPrivate *priv;
+};
+
+struct _SnFlatButtonClass
+{
+  GtkButtonClass parent_class;
+};
+
+GType sn_flat_button_get_type (void);
+GtkWidget *sn_flat_button_new (void);
+
+#if 0
+#ifndef SN_COMPAT_BUTTON_NODRAW_C
+/* replace GtkButton */
+# define gtk_button_get_type sn_compat_button_nodraw_get_type
+#endif
+#endif
+
+G_END_DECLS
+
+#endif
diff --git a/applets/notification_area/status-notifier/sn-item.c b/applets/notification_area/status-notifier/sn-item.c
index fc0401b6..d102a6cc 100644
--- a/applets/notification_area/status-notifier/sn-item.c
+++ b/applets/notification_area/status-notifier/sn-item.c
@@ -57,7 +57,7 @@ static guint signals[LAST_SIGNAL] = { 0 };
 
 static void na_item_init (NaItemInterface *iface);
 
-G_DEFINE_ABSTRACT_TYPE_WITH_CODE (SnItem, sn_item, GTK_TYPE_BUTTON,
+G_DEFINE_ABSTRACT_TYPE_WITH_CODE (SnItem, sn_item, SN_TYPE_FLAT_BUTTON,
                                   G_IMPLEMENT_INTERFACE (GTK_TYPE_ORIENTABLE,
                                                          NULL)
                                   G_IMPLEMENT_INTERFACE (NA_TYPE_ITEM,
diff --git a/applets/notification_area/status-notifier/sn-item.h b/applets/notification_area/status-notifier/sn-item.h
index de7de892..3736c1d8 100644
--- a/applets/notification_area/status-notifier/sn-item.h
+++ b/applets/notification_area/status-notifier/sn-item.h
@@ -20,6 +20,8 @@
 
 #include <gtk/gtk.h>
 
+#include "sn-flat-button.h"
+
 G_BEGIN_DECLS
 
 #define SN_TYPE_ITEM            (sn_item_get_type ())
@@ -41,14 +43,14 @@ typedef struct _SnItemClass   SnItemClass;
 
 struct _SnItem
 {
-  GtkButtonClass parent_instance;
+  SnFlatButtonClass parent_instance;
 
   SnItemPrivate *priv;
 };
 
 struct _SnItemClass
 {
-  GtkButtonClass parent_class;
+  SnFlatButtonClass parent_class;
 
   void          (* ready)              (SnItem            *item);