A ToolPalette allows you to add ToolItems to a palette-like container with different categories and drag and drop support.

A ToolPalette is created with a call to ToolPalette.

ToolItems cannot be added directly to a ToolPalette - instead they are added to a ToolItemGroup which can than be added to a ToolPalette. To add a ToolItemGroup to a ToolPalette, use add.

GtkWidget *palette, *group;
GtkToolItem *item;

palette = gtk_tool_palette_new ();
group = gtk_tool_item_group_new (_("Test Category"));
gtk_container_add (GTK_CONTAINER (palette), group);

item = gtk_tool_button_new (NULL, _("_Open"));
gtk_tool_button_set_icon_name (GTK_TOOL_BUTTON (item), "document-open");
gtk_tool_item_group_insert (GTK_TOOL_ITEM_GROUP (group), item, -1);

The easiest way to use drag and drop with ToolPalette is to call add_drag_dest with the desired drag source palette and the desired drag target widget. Then get_drag_item can be used to get the dragged item in the drag_data_received signal handler of the drag target.

static void
passive_canvas_drag_data_received (GtkWidget        *widget,
                                   GdkDragContext   *context,
                                   gint              x,
                                   gint              y,
                                   GtkSelectionData *selection,
                                   guint             info,
                                   guint             time,
                                   gpointer          data)
{
  GtkWidget *palette;
  GtkWidget *item;

  // Get the dragged item
  palette = gtk_widget_get_ancestor (gtk_drag_get_source_widget (context),
                                     GTK_TYPE_TOOL_PALETTE);
  if (palette != NULL)
    item = gtk_tool_palette_get_drag_item (GTK_TOOL_PALETTE (palette),
                                           selection);

  // Do something with item
}

GtkWidget *target, palette;

palette = gtk_tool_palette_new ();
target = gtk_drawing_area_new ();

g_signal_connect (G_OBJECT (target), "drag-data-received",
                  G_CALLBACK (passive_canvas_drag_data_received), NULL);
gtk_tool_palette_add_drag_dest (GTK_TOOL_PALETTE (palette), target,
                                GTK_DEST_DEFAULT_ALL,
                                GTK_TOOL_PALETTE_DRAG_ITEMS,
                                GDK_ACTION_COPY);

CSS nodes

GtkToolPalette has a single CSS node named toolpalette.

Example: ToolPalette:

public class Application : Gtk.Window {
	public Application () {
		// Prepare Gtk.Window:
		this.title = "My Gtk.ToolPalette";
		this.window_position = Gtk.WindowPosition.CENTER;
		this.destroy.connect (Gtk.main_quit);
		this.set_default_size (150, 200);


		// ToolPalette:
		Gtk.ToolPalette toolpalette = new Gtk.ToolPalette ();
		this.add (toolpalette);

		// ItemGroup 1
		Gtk.ToolItemGroup group = new Gtk.ToolItemGroup ("Group 1");
		toolpalette.add (group);

		Gtk.Image img = new Gtk.Image.from_icon_name ("list-add", Gtk.IconSize.SMALL_TOOLBAR);
		Gtk.ToolButton toolbutton = new Gtk.ToolButton (img, null);
		group.add (toolbutton);

		img = new Gtk.Image.from_icon_name ("dialog-password", Gtk.IconSize.SMALL_TOOLBAR);
		toolbutton = new Gtk.ToolButton (img, null);
		group.add (toolbutton);

		// ItemGroup 2
		group = new Gtk.ToolItemGroup ("Group 2");
		toolpalette.add (group);

		img = new Gtk.Image.from_icon_name ("dialog-warning-symbolic", Gtk.IconSize.SMALL_TOOLBAR);
		toolbutton = new Gtk.ToolButton (img, null);
		group.add (toolbutton);

		img = new Gtk.Image.from_icon_name ("go-home", Gtk.IconSize.SMALL_TOOLBAR);
		toolbutton = new Gtk.ToolButton (img, null);
		group.add (toolbutton);

		img = new Gtk.Image.from_icon_name ("help-about", Gtk.IconSize.SMALL_TOOLBAR);
		toolbutton = new Gtk.ToolButton (img, null);
		group.add(toolbutton);
	}

	public static int main (string[] args) {
		Gtk.init (ref args);

		Application app = new Application ();
		app.show_all ();
		Gtk.main ();
		return 0;
	}
}

valac --pkg gtk+-3.0 Gtk.ToolPalette.vala