st/button: Add :icon-name property

GTK4 added a convenience property for icon-only buttons. While that
use case is not quite as common in the shell as in GTK apps, it still
seems common enough to mirror the GTK API.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2254>

src/st/st-button.c

@@ -40,6 +40,7 @@
 
 #include "st-button.h"
 
+#include "st-icon.h"
 #include "st-enum-types.h"
 #include "st-texture-cache.h"
 #include "st-private.h"
@@ -51,6 +52,7 @@ enum
   PROP_0,
 
   PROP_LABEL,
+  PROP_ICON_NAME,
   PROP_BUTTON_MASK,
   PROP_TOGGLE_MODE,
   PROP_CHECKED,
@@ -400,6 +402,9 @@ st_button_set_property (GObject      *gobject,
     case PROP_LABEL:
       st_button_set_label (button, g_value_get_string (value));
       break;
+    case PROP_ICON_NAME:
+      st_button_set_icon_name (button, g_value_get_string (value));
+      break;
     case PROP_BUTTON_MASK:
       st_button_set_button_mask (button, g_value_get_flags (value));
       break;
@@ -430,6 +435,9 @@ st_button_get_property (GObject    *gobject,
     case PROP_LABEL:
       g_value_set_string (value, priv->text);
       break;
+    case PROP_ICON_NAME:
+      g_value_set_string (value, st_button_get_icon_name (ST_BUTTON (gobject)));
+      break;
     case PROP_BUTTON_MASK:
       g_value_set_flags (value, priv->button_mask);
       break;
@@ -495,6 +503,18 @@ st_button_class_init (StButtonClass *klass)
                          NULL,
                          ST_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
+  /**
+   * StButton:icon-name:
+   *
+   * The icon name of the #StButton.
+   */
+  props[PROP_ICON_NAME] =
+    g_param_spec_string ("icon-name",
+                         "Icon name",
+                         "Icon name of the button",
+                         NULL,
+                         ST_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
   /**
    * StButton:button-mask:
    *
@@ -674,6 +694,66 @@ st_button_set_label (StButton    *button,
   g_object_notify_by_pspec (G_OBJECT (button), props[PROP_LABEL]);
 }
 
+/**
+ * st_button_get_icon_name:
+ * @button: a #StButton
+ *
+ * Get the icon name of the button. If the button isn't showing an icon,
+ * the return value will be %NULL.
+ *
+ * Returns: (transfer none) (nullable): the icon name of the button
+ */
+const char *
+st_button_get_icon_name (StButton *button)
+{
+  ClutterActor *icon;
+
+  g_return_val_if_fail (ST_IS_BUTTON (button), NULL);
+
+  icon = st_bin_get_child (ST_BIN (button));
+  if (ST_IS_ICON (icon))
+    return st_icon_get_icon_name (ST_ICON (icon));
+  return NULL;
+}
+
+/**
+ * st_button_set_icon_name:
+ * @button: a #Stbutton
+ * @icon_name: an icon name
+ *
+ * Adds an `StIcon` with the given icon name as a child.
+ *
+ * If @button already contains a child actor, that child will
+ * be removed and replaced with the icon.
+ */
+void
+st_button_set_icon_name (StButton   *button,
+                         const char *icon_name)
+{
+  ClutterActor *icon;
+
+  g_return_if_fail (ST_IS_BUTTON (button));
+  g_return_if_fail (icon_name != NULL);
+
+  icon = st_bin_get_child (ST_BIN (button));
+
+  if (ST_IS_ICON (icon))
+    {
+      st_icon_set_icon_name (ST_ICON (icon), icon_name);
+    }
+  else
+    {
+      icon = g_object_new (ST_TYPE_ICON,
+                           "icon-name", icon_name,
+                           "x-align", CLUTTER_ACTOR_ALIGN_CENTER,
+                           "y-align", CLUTTER_ACTOR_ALIGN_CENTER,
+                           NULL);
+      st_bin_set_child (ST_BIN (button), icon);
+    }
+
+  g_object_notify_by_pspec (G_OBJECT (button), props[PROP_ICON_NAME]);
+}
+
 /**
  * st_button_get_button_mask:
  * @button: a #StButton

src/st/st-button.h

@@ -48,6 +48,9 @@ StWidget    *st_button_new_with_label  (const gchar  *text);
 const gchar *st_button_get_label       (StButton     *button);
 void         st_button_set_label       (StButton     *button,
                                         const gchar  *text);
+const char  *st_button_get_icon_name   (StButton     *button);
+void         st_button_set_icon_name   (StButton     *button,
+                                        const char   *icon_name);
 void         st_button_set_toggle_mode (StButton     *button,
                                         gboolean      toggle);
 gboolean     st_button_get_toggle_mode (StButton     *button);