Move the library toolbar to its own class.

8 files changed, 943 insertions, 507 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f805554..5e7bc77 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -115,6 +115,7 @@ set (liblogdiag_SOURCES
 	liblogdiag/ld-diagram-symbol.c
 	liblogdiag/ld-canvas.c
 	liblogdiag/ld-library.c
+	liblogdiag/ld-library-toolbar.c
 	liblogdiag/ld-symbol-category.c
 	liblogdiag/ld-symbol.c
 	liblogdiag/ld-lua.c
@@ -129,6 +130,7 @@ set (liblogdiag_HEADERS
 	liblogdiag/ld-diagram-symbol.h
 	liblogdiag/ld-canvas.h
 	liblogdiag/ld-library.h
+	liblogdiag/ld-library-toolbar.h
 	liblogdiag/ld-symbol-category.h
 	liblogdiag/ld-symbol.h
 	liblogdiag/ld-lua.h
diff --git a/liblogdiag/ld-library-toolbar.c b/liblogdiag/ld-library-toolbar.c
new file mode 100644
index 0000000..c809f1e
--- /dev/null
+++ b/liblogdiag/ld-library-toolbar.c
@@ -0,0 +1,773 @@
+/*
+ * ld-library-toolbar.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2011. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include "liblogdiag.h"
+#include "config.h"
+
+
+/**
+ * SECTION:ld-library-toolbar
+ * @short_description: A library toolbar.
+ * @see_also: #LdLibrary
+ *
+ * #LdLibraryToolbar enables the user to choose symbols from an #LdLibrary.
+ */
+
+#define LIBRARY_TOOLBAR_ICON_WIDTH 32
+
+/*
+ * SymbolMenuItem:
+ *
+ * Data related to a symbol in an open symbol menu.
+ */
+typedef struct _SymbolMenuItem SymbolMenuItem;
+
+struct _SymbolMenuItem
+{
+	LdSymbol *symbol;
+	gchar *klass;
+
+	gint width;
+	gdouble dx;
+	gdouble scale;
+};
+
+/*
+ * SymbolMenuData:
+ *
+ * Data related to the currently opened symbol menu.
+ */
+typedef struct _SymbolMenuData SymbolMenuData;
+
+struct _SymbolMenuData
+{
+	GtkToggleButton *active_button;
+
+	SymbolMenuItem *items;
+	gint n_items;
+	gint active_item;
+
+	gint menu_width;
+	gint menu_height;
+	gint menu_y;
+};
+
+enum
+{
+	CANVAS_HANDLER_EXPOSE,
+	CANVAS_HANDLER_MOTION_NOTIFY,
+	CANVAS_HANDLER_BUTTON_PRESS,
+	CANVAS_HANDLER_BUTTON_RELEASE,
+	CANVAS_HANDLER_COUNT
+};
+
+/*
+ * LdLibraryToolbarPrivate:
+ * @library: A library object assigned to this canvas as a model.
+ * @canvas: A canvas object for showing symbol menus.
+ * @canvas_handlers: Signal handlers that hook the canvas.
+ * @symbol_menu: Data related to menus.
+ */
+struct _LdLibraryToolbarPrivate
+{
+	LdLibrary *library;
+	LdCanvas *canvas;
+	gulong canvas_handlers[CANVAS_HANDLER_COUNT];
+	SymbolMenuData symbol_menu;
+};
+
+enum
+{
+	PROP_0,
+	PROP_LIBRARY,
+	PROP_CANVAS
+};
+
+static void ld_library_toolbar_get_property (GObject *object, guint property_id,
+	GValue *value, GParamSpec *pspec);
+static void ld_library_toolbar_set_property (GObject *object, guint property_id,
+	const GValue *value, GParamSpec *pspec);
+static void ld_library_toolbar_dispose (GObject *gobject);
+
+static void reload_library (LdLibraryToolbar *self);
+static void load_category_cb (gpointer data, gpointer user_data);
+static GdkPixbuf *recolor_pixbuf (GdkPixbuf *pbuf, GdkColor *color);
+
+static void redraw_symbol_menu (LdLibraryToolbar *self);
+static void emit_symbol_signal (LdLibraryToolbar *self,
+	guint signal_id, gint menu_index);
+static void on_category_toggle (GtkToggleButton *toggle_button,
+	gpointer user_data);
+
+static inline void block_canvas_handlers (LdLibraryToolbar *self);
+static inline void unblock_canvas_handlers (LdLibraryToolbar *self);
+static inline void disconnect_canvas_handlers (LdLibraryToolbar *self);
+static gboolean on_canvas_exposed (GtkWidget *widget,
+	GdkEventExpose *event, gpointer user_data);
+static gboolean on_canvas_motion_notify (GtkWidget *widget,
+	GdkEventMotion *event, gpointer user_data);
+static gboolean on_canvas_button_press (GtkWidget *widget,
+	GdkEventButton *event, gpointer user_data);
+static gboolean on_canvas_button_release (GtkWidget *widget,
+	GdkEventButton *event, gpointer user_data);
+
+
+G_DEFINE_TYPE (LdLibraryToolbar, ld_library_toolbar, GTK_TYPE_TOOLBAR);
+
+static void
+ld_library_toolbar_class_init (LdLibraryToolbarClass *klass)
+{
+	GObjectClass *object_class;
+	GtkWidgetClass *widget_class;
+	GParamSpec *pspec;
+
+	widget_class = GTK_WIDGET_CLASS (klass);
+
+	object_class = G_OBJECT_CLASS (klass);
+	object_class->get_property = ld_library_toolbar_get_property;
+	object_class->set_property = ld_library_toolbar_set_property;
+	object_class->dispose = ld_library_toolbar_dispose;
+
+/**
+ * LdLibraryToolbar:library:
+ *
+ * The #LdLibrary that this canvas retrieves symbols from.
+ */
+	pspec = g_param_spec_object ("library", "Library",
+		"The library that this canvas retrieves symbols from.",
+		LD_TYPE_LIBRARY, G_PARAM_READWRITE);
+	g_object_class_install_property (object_class, PROP_LIBRARY, pspec);
+
+/**
+ * LdLibraryToolbar:canvas:
+ *
+ * The #LdCanvas misused for showing symbol menus.
+ */
+	pspec = g_param_spec_object ("canvas", "Canvas",
+		"The canvas misused for showing symbol menus.",
+		LD_TYPE_CANVAS, G_PARAM_READWRITE);
+	g_object_class_install_property (object_class, PROP_CANVAS, pspec);
+
+/**
+ * LdLibraryToolbar::symbol-chosen:
+ * @self: An #LdLibraryToolbar object.
+ * @symbol: The chosen #LdSymbol object.
+ * @klass: Location of the symbol within the library.
+ *
+ * A symbol has been chosen.
+ */
+	klass->symbol_chosen_signal = g_signal_new
+		("symbol-chosen", G_TYPE_FROM_CLASS (klass),
+		G_SIGNAL_RUN_LAST, 0, NULL, NULL,
+		g_cclosure_user_marshal_VOID__OBJECT_STRING,
+		G_TYPE_NONE, 2, LD_TYPE_SYMBOL,
+		G_TYPE_STRING | G_SIGNAL_TYPE_STATIC_SCOPE);
+
+/**
+ * LdLibraryToolbar::symbol-selected:
+ * @self: An #LdLibraryToolbar object.
+ * @symbol: The selected #LdSymbol object.
+ * @klass: Location of the symbol within the library.
+ *
+ * A symbol has been selected.
+ */
+	klass->symbol_selected_signal = g_signal_new
+		("symbol-selected", G_TYPE_FROM_CLASS (klass),
+		G_SIGNAL_RUN_LAST, 0, NULL, NULL,
+		g_cclosure_user_marshal_VOID__OBJECT_STRING,
+		G_TYPE_NONE, 2, LD_TYPE_SYMBOL,
+		G_TYPE_STRING | G_SIGNAL_TYPE_STATIC_SCOPE);
+
+/**
+ * LdLibraryToolbar::symbol-deselected:
+ * @self: An #LdLibraryToolbar object.
+ * @symbol: The deselected #LdSymbol object.
+ * @klass: Location of the symbol within the library.
+ *
+ * A symbol has been deselected.
+ */
+	klass->symbol_deselected_signal = g_signal_new
+		("symbol-deselected", G_TYPE_FROM_CLASS (klass),
+		G_SIGNAL_RUN_LAST, 0, NULL, NULL,
+		g_cclosure_user_marshal_VOID__OBJECT_STRING,
+		G_TYPE_NONE, 2, LD_TYPE_SYMBOL,
+		G_TYPE_STRING | G_SIGNAL_TYPE_STATIC_SCOPE);
+
+	g_type_class_add_private (klass, sizeof (LdLibraryToolbarPrivate));
+}
+
+static void
+ld_library_toolbar_init (LdLibraryToolbar *self)
+{
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+		(self, LD_TYPE_LIBRARY_TOOLBAR, LdLibraryToolbarPrivate);
+}
+
+static void
+ld_library_toolbar_dispose (GObject *gobject)
+{
+	LdLibraryToolbar *self;
+
+	self = LD_LIBRARY_TOOLBAR (gobject);
+
+	ld_library_toolbar_set_library (self, NULL);
+	ld_library_toolbar_set_canvas (self, NULL);
+
+	/* Chain up to the parent class. */
+	G_OBJECT_CLASS (ld_library_toolbar_parent_class)->dispose (gobject);
+}
+
+static void
+ld_library_toolbar_get_property (GObject *object, guint property_id,
+	GValue *value, GParamSpec *pspec)
+{
+	LdLibraryToolbar *self;
+
+	self = LD_LIBRARY_TOOLBAR (object);
+	switch (property_id)
+	{
+	case PROP_LIBRARY:
+		g_value_set_object (value, ld_library_toolbar_get_library (self));
+		break;
+	case PROP_CANVAS:
+		g_value_set_object (value, ld_library_toolbar_get_canvas (self));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+	}
+}
+
+static void
+ld_library_toolbar_set_property (GObject *object, guint property_id,
+	const GValue *value, GParamSpec *pspec)
+{
+	LdLibraryToolbar *self;
+
+	self = LD_LIBRARY_TOOLBAR (object);
+	switch (property_id)
+	{
+	case PROP_LIBRARY:
+		ld_library_toolbar_set_library (self,
+			LD_LIBRARY (g_value_get_object (value)));
+		break;
+	case PROP_CANVAS:
+		ld_library_toolbar_set_canvas (self,
+			LD_CANVAS (g_value_get_object (value)));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+	}
+}
+
+
+/**
+ * ld_library_toolbar_new:
+ *
+ * Create an instance.
+ */
+GtkWidget *
+ld_library_toolbar_new (void)
+{
+	return g_object_new (LD_TYPE_LIBRARY_TOOLBAR, NULL);
+}
+
+/**
+ * ld_library_toolbar_set_library:
+ * @self: An #LdLibraryToolbar object.
+ * @library: (allow-none): The #LdLibrary to be assigned to the toolbar.
+ *
+ * Assign an #LdLibrary object to the toolbar.
+ */
+void
+ld_library_toolbar_set_library (LdLibraryToolbar *self, LdLibrary *library)
+{
+	g_return_if_fail (LD_IS_LIBRARY_TOOLBAR (self));
+	g_return_if_fail (LD_IS_LIBRARY (library) || library == NULL);
+
+	if (self->priv->library)
+	{
+		g_signal_handlers_disconnect_by_func (self->priv->library,
+			reload_library, self);
+		g_object_unref (self->priv->library);
+	}
+
+	self->priv->library = library;
+
+	if (library)
+	{
+		g_signal_connect_data (library, "changed",
+			G_CALLBACK (reload_library), self,
+			NULL, G_CONNECT_AFTER | G_CONNECT_SWAPPED);
+		g_object_ref (library);
+	}
+	reload_library (self);
+	g_object_notify (G_OBJECT (self), "library");
+}
+
+/**
+ * ld_library_toolbar_get_library:
+ * @self: An #LdLibraryToolbar object.
+ *
+ * Get the #LdLibrary object assigned to this toolbar.
+ * The reference count on the library is not incremented.
+ */
+LdLibrary *
+ld_library_toolbar_get_library (LdLibraryToolbar *self)
+{
+	g_return_val_if_fail (LD_IS_LIBRARY_TOOLBAR (self), NULL);
+	return self->priv->library;
+}
+
+/**
+ * ld_library_toolbar_set_canvas:
+ * @self: An #LdLibraryToolbar object.
+ * @canvas: (allow-none): The #LdCanvas to be assigned to the toolbar.
+ *
+ * Assign an #LdCanvas object to the toolbar.
+ */
+void
+ld_library_toolbar_set_canvas (LdLibraryToolbar *self, LdCanvas *canvas)
+{
+	g_return_if_fail (LD_IS_LIBRARY_TOOLBAR (self));
+	g_return_if_fail (LD_IS_CANVAS (canvas) || canvas == NULL);
+
+	if (self->priv->canvas)
+	{
+		disconnect_canvas_handlers (self);
+		g_object_unref (self->priv->canvas);
+	}
+
+	self->priv->canvas = canvas;
+
+	if (canvas)
+	{
+		self->priv->canvas_handlers[CANVAS_HANDLER_EXPOSE]
+			= g_signal_connect (canvas, "expose-event",
+			G_CALLBACK (on_canvas_exposed), self);
+		self->priv->canvas_handlers[CANVAS_HANDLER_MOTION_NOTIFY]
+			= g_signal_connect (canvas, "motion-notify-event",
+			G_CALLBACK (on_canvas_motion_notify), self);
+		self->priv->canvas_handlers[CANVAS_HANDLER_BUTTON_PRESS]
+			= g_signal_connect (canvas, "button-press-event",
+			G_CALLBACK (on_canvas_button_press), self);
+		self->priv->canvas_handlers[CANVAS_HANDLER_BUTTON_RELEASE]
+			= g_signal_connect (canvas, "button-release-event",
+			G_CALLBACK (on_canvas_button_release), self);
+
+		block_canvas_handlers (self);
+		g_object_ref (canvas);
+	}
+	g_object_notify (G_OBJECT (self), "canvas");
+}
+
+/**
+ * ld_library_toolbar_get_canvas:
+ * @self: An #LdLibraryToolbar object.
+ *
+ * Get the #LdLibrary object assigned to this toolbar.
+ * The reference count on the canvas is not incremented.
+ */
+LdCanvas *
+ld_library_toolbar_get_canvas (LdLibraryToolbar *self)
+{
+	g_return_val_if_fail (LD_IS_LIBRARY_TOOLBAR (self), NULL);
+	return self->priv->canvas;
+}
+
+static void
+reload_library (LdLibraryToolbar *self)
+{
+	g_return_if_fail (LD_IS_LIBRARY_TOOLBAR (self));
+
+	/* Clear the toolbar first, if there was already something in it. */
+	gtk_container_foreach (GTK_CONTAINER (self),
+		(GtkCallback) gtk_widget_destroy, NULL);
+
+	if (self->priv->library)
+	{
+		GSList *categories;
+
+		categories = (GSList *) ld_library_get_children (self->priv->library);
+		g_slist_foreach (categories, load_category_cb, self);
+	}
+}
+
+static void
+load_category_cb (gpointer data, gpointer user_data)
+{
+	LdLibraryToolbar *self;
+	LdSymbolCategory *cat;
+	const gchar *human_name;
+	GdkPixbuf *pbuf, *new_pbuf;
+	GtkWidget *img;
+	GtkToolItem *item;
+	GtkWidget *button;
+	GtkStyle *style;
+
+	g_return_if_fail (LD_IS_LIBRARY_TOOLBAR (user_data));
+	g_return_if_fail (LD_IS_SYMBOL_CATEGORY (data));
+
+	self = user_data;
+	cat = data;
+
+	pbuf = gdk_pixbuf_new_from_file_at_size	(ld_symbol_category_get_image_path
+		(cat), LIBRARY_TOOLBAR_ICON_WIDTH, -1, NULL);
+	g_return_if_fail (pbuf != NULL);
+
+	button = gtk_toggle_button_new ();
+	style = gtk_rc_get_style (button);
+
+	/* TODO: Handle all states. */
+	new_pbuf = recolor_pixbuf (pbuf, &style->fg[GTK_STATE_NORMAL]);
+	if (new_pbuf)
+	{
+		g_object_unref (pbuf);
+		pbuf = new_pbuf;
+	}
+
+	img = gtk_image_new_from_pixbuf (pbuf);
+	g_object_unref (pbuf);
+
+	item = gtk_tool_item_new ();
+	gtk_container_add (GTK_CONTAINER (button), img);
+	gtk_container_add (GTK_CONTAINER (item), button);
+
+	/* Don't steal focus from the canvas. */
+	g_object_set (button, "can-focus", FALSE, NULL);
+
+	/* Assign the category to the toggle button. */
+	g_object_ref (cat);
+	g_object_set_data_full (G_OBJECT (button),
+		"category", cat, (GDestroyNotify) g_object_unref);
+
+	/* Hook toggling of the button. */
+	g_signal_connect (button, "toggled", G_CALLBACK (on_category_toggle), self);
+
+	human_name = ld_symbol_category_get_human_name (cat);
+	gtk_tool_item_set_tooltip_text (item, human_name);
+	gtk_toolbar_insert (GTK_TOOLBAR (self), item, 0);
+}
+
+static GdkPixbuf *
+recolor_pixbuf (GdkPixbuf *pbuf, GdkColor *color)
+{
+	gint width, height;
+	GdkPixbuf *new_pbuf;
+	cairo_surface_t *cr_surface;
+	cairo_t *cr;
+
+	width  = gdk_pixbuf_get_width  (pbuf);
+	height = gdk_pixbuf_get_height (pbuf);
+
+	new_pbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, width, height);
+	g_return_val_if_fail (new_pbuf != NULL, NULL);
+
+	cr_surface = cairo_image_surface_create_for_data
+		(gdk_pixbuf_get_pixels (new_pbuf), CAIRO_FORMAT_ARGB32,
+		width, height, gdk_pixbuf_get_rowstride (new_pbuf));
+	cr = cairo_create (cr_surface);
+
+	/* Change the color of all pixels but leave the alpha channel intact. */
+	gdk_cairo_set_source_color (cr, color);
+	cairo_paint (cr);
+
+	cairo_set_operator (cr, CAIRO_OPERATOR_DEST_IN);
+	gdk_cairo_set_source_pixbuf (cr, pbuf, 0, 0);
+	cairo_paint (cr);
+
+	cairo_destroy (cr);
+	cairo_surface_destroy (cr_surface);
+	return new_pbuf;
+}
+
+static void
+redraw_symbol_menu (LdLibraryToolbar *self)
+{
+	SymbolMenuData *data;
+
+	g_return_if_fail (LD_IS_LIBRARY_TOOLBAR (self));
+	data = &self->priv->symbol_menu;
+
+	gtk_widget_queue_draw_area (GTK_WIDGET (self->priv->canvas),
+		0, data->menu_y - 1, data->menu_width + 2, data->menu_height + 2);
+}
+
+static void
+emit_symbol_signal (LdLibraryToolbar *self, guint signal_id, gint menu_index)
+{
+	SymbolMenuData *data;
+	SymbolMenuItem *item;
+
+	data = &self->priv->symbol_menu;
+	if (menu_index == -1)
+		menu_index = data->active_item;
+	if (menu_index != -1)
+	{
+		item = &data->items[menu_index];
+		g_signal_emit (self, signal_id, 0, item->symbol, item->klass);
+	}
+}
+
+static void
+on_category_toggle (GtkToggleButton *toggle_button, gpointer user_data)
+{
+	LdLibraryToolbar *self;
+	LdLibraryToolbarPrivate *priv;
+	LdSymbolCategory *cat;
+	SymbolMenuData *data;
+	const gchar *category_name, *symbol_name;
+
+	cat = g_object_get_data (G_OBJECT (toggle_button), "category");
+	self = LD_LIBRARY_TOOLBAR (user_data);
+	priv = self->priv;
+	data = &priv->symbol_menu;
+
+	/* First untoggle any active button. */
+	if (data->active_button)
+		gtk_toggle_button_set_active (data->active_button, FALSE);
+
+	/* And toggle signal handlers that enable the user to add a symbol. */
+	if (data->active_button == toggle_button)
+	{
+		gint i;
+
+		block_canvas_handlers (self);
+
+		g_object_unref (data->active_button);
+		data->active_button = NULL;
+
+		emit_symbol_signal (self, LD_LIBRARY_TOOLBAR_GET_CLASS (self)
+			->symbol_deselected_signal, -1);
+
+		/* Ashes to ashes, NULL to NULL. */
+		for (i = 0; i < data->n_items; i++)
+		{
+			g_object_unref (data->items[i].symbol);
+			g_free (data->items[i].klass);
+		}
+
+		g_free (data->items);
+		data->items = NULL;
+
+		gtk_grab_remove (GTK_WIDGET (self->priv->canvas));
+	}
+	else
+	{
+		const GSList *children, *symbol_iter;
+		SymbolMenuItem *item;
+		gint x, y, menu_width;
+
+		g_return_if_fail (gtk_widget_translate_coordinates (GTK_WIDGET
+			(toggle_button), GTK_WIDGET (priv->canvas), 0, 0, &x, &y));
+
+		data->menu_y = y;
+		data->menu_height = GTK_WIDGET (toggle_button)->allocation.height;
+
+		unblock_canvas_handlers (self);
+
+		data->active_button = toggle_button;
+		g_object_ref (data->active_button);
+
+		category_name = ld_symbol_category_get_name (cat);
+		children = ld_symbol_category_get_children (cat);
+
+		data->n_items = g_slist_length ((GSList *) children);
+		data->items = g_new (SymbolMenuItem, data->n_items);
+		data->active_item = -1;
+
+		item = data->items;
+		menu_width = 0;
+		for (symbol_iter = children; symbol_iter;
+			symbol_iter = symbol_iter->next)
+		{
+			LdRectangle area;
+
+			item->symbol = LD_SYMBOL (symbol_iter->data);
+			g_object_ref (item->symbol);
+
+			symbol_name = ld_symbol_get_name (item->symbol);
+			item->klass = g_build_path (LD_LIBRARY_IDENTIFIER_SEPARATOR,
+				category_name, symbol_name, NULL);
+
+			ld_symbol_get_area (item->symbol, &area);
+
+			/* This is the height when the center of the symbol is
+			 * in the center of it's symbol menu item.
+			 */
+			item->scale = data->menu_height * 0.5
+				/ MAX (ABS (area.y), ABS (area.y + area.height)) * 0.5;
+			item->width = data->menu_height * 0.5 + item->scale * area.width;
+			item->dx = item->width * 0.5 + item->scale * (area.width * 0.5
+				- MAX (ABS (area.x), ABS (area.x + area.width)));
+
+			menu_width += item++->width;
+		}
+		data->menu_width = menu_width;
+
+		gtk_grab_add (GTK_WIDGET (self->priv->canvas));
+	}
+	redraw_symbol_menu (self);
+}
+
+#define DEFINE_CANVAS_HANDLER_FUNC(name) \
+static inline void \
+name ## _canvas_handlers (LdLibraryToolbar *self) \
+{ \
+	gint i; \
+	g_return_if_fail (LD_IS_CANVAS (self->priv->canvas)); \
+	for (i = 0; i < CANVAS_HANDLER_COUNT; i++) \
+		g_signal_handler_ ## name (self->priv->canvas, \
+			self->priv->canvas_handlers[i]); \
+}
+
+DEFINE_CANVAS_HANDLER_FUNC (block)
+DEFINE_CANVAS_HANDLER_FUNC (unblock)
+DEFINE_CANVAS_HANDLER_FUNC (disconnect)
+
+static gboolean
+on_canvas_exposed (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
+{
+	cairo_t *cr;
+	LdLibraryToolbar *self;
+	SymbolMenuData *data;
+	gint i, x;
+
+	cr = gdk_cairo_create (widget->window);
+	self = LD_LIBRARY_TOOLBAR (user_data);
+	data = &self->priv->symbol_menu;
+
+	/* Draw some border. */
+	cairo_set_line_width (cr, 1);
+
+	cairo_rectangle (cr, 0, data->menu_y, data->menu_width, data->menu_height);
+	cairo_set_source_rgb (cr, 1, 1, 1);
+	cairo_fill (cr);
+
+	/* Draw all symbols from that category. */
+	for (x = i = 0; i < data->n_items; i++)
+	{
+		SymbolMenuItem *item;
+
+		item = data->items + i;
+		cairo_save (cr);
+
+		cairo_rectangle (cr, x, data->menu_y, item->width, data->menu_height);
+		cairo_clip (cr);
+
+		if (i == data->active_item)
+		{
+			cairo_set_source_rgb (cr, 0.9, 0.9, 0.9);
+			cairo_paint (cr);
+		}
+
+		cairo_translate (cr, x + item->dx,
+			data->menu_y + data->menu_height * 0.5);
+		cairo_scale (cr, item->scale, item->scale);
+
+		cairo_set_source_rgb (cr, 0, 0, 0);
+		cairo_set_line_width (cr, 1 / item->scale);
+		ld_symbol_draw (item->symbol, cr);
+
+		cairo_restore (cr);
+		x += item->width;
+	}
+
+	cairo_rectangle (cr, 0, data->menu_y, data->menu_width, data->menu_height);
+	cairo_set_source_rgb (cr, 0, 0, 0);
+	cairo_stroke (cr);
+
+	cairo_destroy (cr);
+	return FALSE;
+}
+
+static gboolean
+on_canvas_motion_notify (GtkWidget *widget, GdkEventMotion *event,
+	gpointer user_data)
+{
+	LdLibraryToolbar *self;
+	SymbolMenuData *data;
+	gint i, x, at_cursor = -1;
+
+	self = LD_LIBRARY_TOOLBAR (user_data);
+	data = &self->priv->symbol_menu;
+
+	if (widget->window != event->window
+		|| event->x < 0 || event->y < data->menu_y
+		|| event->y >= data->menu_y + data->menu_height)
+		goto on_canvas_motion_notify_end;
+
+	for (x = i = 0; i < data->n_items; i++)
+	{
+		x += data->items[i].width;
+		if (event->x < x)
+		{
+			at_cursor = i;
+			break;
+		}
+	}
+
+on_canvas_motion_notify_end:
+	if (data->active_item != at_cursor)
+	{
+		emit_symbol_signal (self, LD_LIBRARY_TOOLBAR_GET_CLASS (self)
+			->symbol_deselected_signal, -1);
+
+		if (at_cursor != -1)
+			emit_symbol_signal (self, LD_LIBRARY_TOOLBAR_GET_CLASS (self)
+				->symbol_selected_signal, at_cursor);
+	}
+	data->active_item = at_cursor;
+	redraw_symbol_menu (self);
+	return FALSE;
+}
+
+static gboolean
+on_canvas_button_press (GtkWidget *widget, GdkEventButton *event,
+	gpointer user_data)
+{
+	LdLibraryToolbar *self;
+	SymbolMenuData *data;
+
+	self = LD_LIBRARY_TOOLBAR (user_data);
+	data = &self->priv->symbol_menu;
+
+	/* If the event occured elsewhere, cancel the menu and put the event
+	 * back into the queue.
+	 */
+	if (widget->window != event->window && data->active_button)
+	{
+		gtk_toggle_button_set_active (data->active_button, FALSE);
+		gdk_event_put ((GdkEvent *) event);
+	}
+	return FALSE;
+}
+
+static gboolean
+on_canvas_button_release (GtkWidget *widget, GdkEventButton *event,
+	gpointer user_data)
+{
+	LdLibraryToolbar *self;
+	SymbolMenuData *data;
+
+	self = LD_LIBRARY_TOOLBAR (user_data);
+	data = &self->priv->symbol_menu;
+
+	if (event->button != 1)
+		return FALSE;
+
+	emit_symbol_signal (self, LD_LIBRARY_TOOLBAR_GET_CLASS (self)
+		->symbol_chosen_signal, -1);
+
+	/* We've either chosen a symbol or canceled the menu, so hide it. */
+	if (data->active_button)
+		gtk_toggle_button_set_active (data->active_button, FALSE);
+
+	return FALSE;
+}
diff --git a/liblogdiag/ld-library-toolbar.h b/liblogdiag/ld-library-toolbar.h
new file mode 100644
index 0000000..96b9750
--- /dev/null
+++ b/liblogdiag/ld-library-toolbar.h
@@ -0,0 +1,69 @@
+/*
+ * ld-library-toolbar.h
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2011. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#ifndef __LD_LIBRARY_TOOLBAR_H__
+#define __LD_LIBRARY_TOOLBAR_H__
+
+G_BEGIN_DECLS
+
+
+#define LD_TYPE_LIBRARY_TOOLBAR (ld_library_toolbar_get_type ())
+#define LD_LIBRARY_TOOLBAR(obj) (G_TYPE_CHECK_INSTANCE_CAST \
+	((obj), LD_TYPE_LIBRARY_TOOLBAR, LdLibraryToolbar))
+#define LD_LIBRARY_TOOLBAR_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
+	((klass), LD_TYPE_LIBRARY_TOOLBAR, LdLibraryToolbarClass))
+#define LD_IS_LIBRARY_TOOLBAR(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((obj), LD_TYPE_LIBRARY_TOOLBAR))
+#define LD_IS_LIBRARY_TOOLBAR_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((klass), LD_TYPE_LIBRARY_TOOLBAR))
+#define LD_LIBRARY_TOOLBAR_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
+	((obj), LD_LIBRARY_TOOLBAR, LdLibraryToolbarClass))
+
+typedef struct _LdLibraryToolbar LdLibraryToolbar;
+typedef struct _LdLibraryToolbarPrivate LdLibraryToolbarPrivate;
+typedef struct _LdLibraryToolbarClass LdLibraryToolbarClass;
+
+
+/**
+ * LdLibraryToolbar:
+ */
+struct _LdLibraryToolbar
+{
+/*< private >*/
+	GtkToolbar parent_instance;
+	LdLibraryToolbarPrivate *priv;
+};
+
+struct _LdLibraryToolbarClass
+{
+/*< private >*/
+	GtkToolbarClass parent_class;
+
+	guint symbol_chosen_signal;
+	guint symbol_selected_signal;
+	guint symbol_deselected_signal;
+};
+
+
+GType ld_library_toolbar_get_type (void) G_GNUC_CONST;
+
+GtkWidget *ld_library_toolbar_new (void);
+
+void ld_library_toolbar_set_library (LdLibraryToolbar *self,
+	LdLibrary *library);
+LdLibrary *ld_library_toolbar_get_library (LdLibraryToolbar *self);
+void ld_library_toolbar_set_canvas (LdLibraryToolbar *self,
+	LdCanvas *canvas);
+LdCanvas *ld_library_toolbar_get_canvas (LdLibraryToolbar *self);
+
+
+G_END_DECLS
+
+#endif /* ! __LD_LIBRARY_TOOLBAR_H__ */
diff --git a/liblogdiag/ld-marshal.c b/liblogdiag/ld-marshal.c
index ac88836..2eaa7b3 100644
--- a/liblogdiag/ld-marshal.c
+++ b/liblogdiag/ld-marshal.c
@@ -86,3 +86,40 @@ g_cclosure_user_marshal_VOID__OBJECT_OBJECT (GClosure     *closure,
             data2);
 }
 
+/* VOID:OBJECT,STRING (ld-marshal.list:2) */
+void
+g_cclosure_user_marshal_VOID__OBJECT_STRING (GClosure     *closure,
+                                             GValue       *return_value G_GNUC_UNUSED,
+                                             guint         n_param_values,
+                                             const GValue *param_values,
+                                             gpointer      invocation_hint G_GNUC_UNUSED,
+                                             gpointer      marshal_data)
+{
+  typedef void (*GMarshalFunc_VOID__OBJECT_STRING) (gpointer     data1,
+                                                    gpointer     arg_1,
+                                                    gpointer     arg_2,
+                                                    gpointer     data2);
+  register GMarshalFunc_VOID__OBJECT_STRING callback;
+  register GCClosure *cc = (GCClosure*) closure;
+  register gpointer data1, data2;
+
+  g_return_if_fail (n_param_values == 3);
+
+  if (G_CCLOSURE_SWAP_DATA (closure))
+    {
+      data1 = closure->data;
+      data2 = g_value_peek_pointer (param_values + 0);
+    }
+  else
+    {
+      data1 = g_value_peek_pointer (param_values + 0);
+      data2 = closure->data;
+    }
+  callback = (GMarshalFunc_VOID__OBJECT_STRING) (marshal_data ? marshal_data : cc->callback);
+
+  callback (data1,
+            g_marshal_value_peek_object (param_values + 1),
+            g_marshal_value_peek_string (param_values + 2),
+            data2);
+}
+
diff --git a/liblogdiag/ld-marshal.h b/liblogdiag/ld-marshal.h
index 545735a..cdf28a7 100644
--- a/liblogdiag/ld-marshal.h
+++ b/liblogdiag/ld-marshal.h
@@ -14,6 +14,14 @@ extern void g_cclosure_user_marshal_VOID__OBJECT_OBJECT (GClosure     *closure,
                                                          gpointer      invocation_hint,
                                                          gpointer      marshal_data);
 
+/* VOID:OBJECT,STRING (ld-marshal.list:2) */
+extern void g_cclosure_user_marshal_VOID__OBJECT_STRING (GClosure     *closure,
+                                                         GValue       *return_value,
+                                                         guint         n_param_values,
+                                                         const GValue *param_values,
+                                                         gpointer      invocation_hint,
+                                                         gpointer      marshal_data);
+
 G_END_DECLS
 
 #endif /* __g_cclosure_user_marshal_MARSHAL_H__ */
diff --git a/liblogdiag/ld-marshal.list b/liblogdiag/ld-marshal.list
index 38076d6..20c67c0 100644
--- a/liblogdiag/ld-marshal.list
+++ b/liblogdiag/ld-marshal.list
@@ -1 +1,2 @@
 VOID:OBJECT,OBJECT
+VOID:OBJECT,STRING
diff --git a/liblogdiag/liblogdiag.h b/liblogdiag/liblogdiag.h
index 800826f..61b6149 100644
--- a/liblogdiag/liblogdiag.h
+++ b/liblogdiag/liblogdiag.h
@@ -26,6 +26,7 @@
 #include "ld-diagram.h"
 
 #include "ld-canvas.h"
+#include "ld-library-toolbar.h"
 
 #include "ld-lua.h"
 #include "ld-lua-symbol.h"
diff --git a/src/ld-window-main.c b/src/ld-window-main.c
index d1ad567..df0e5fb 100644
--- a/src/ld-window-main.c
+++ b/src/ld-window-main.c
@@ -23,47 +23,6 @@
  * #LdWindowMain is the main window of the application.
  */
 
-/*
- * SymbolMenuItem:
- *
- * Data related to a symbol in an open symbol menu.
- */
-typedef struct _SymbolMenuItem SymbolMenuItem;
-
-struct _SymbolMenuItem
-{
-	LdSymbol *symbol;
-
-	gint width;
-	gdouble dx;
-	gdouble scale;
-};
-
-/*
- * SymbolMenuData:
- *
- * Data related to the currently opened symbol menu.
- */
-typedef struct _SymbolMenuData SymbolMenuData;
-
-struct _SymbolMenuData
-{
-	gulong expose_handler;
-	gulong motion_notify_handler;
-	gulong button_press_handler;
-	gulong button_release_handler;
-
-	GtkToggleButton *active_button;
-
-	SymbolMenuItem *items;
-	gint n_items;
-	gint active_item;
-
-	gint menu_width;
-	gint menu_height;
-	gint menu_y;
-};
-
 struct _LdWindowMainPrivate
 {
 	GtkUIManager *ui_manager;
@@ -86,33 +45,13 @@ struct _LdWindowMainPrivate
 	GtkWidget *statusbar;
 	guint statusbar_symbol_context_id;
 	guint statusbar_menu_context_id;
-
-	SymbolMenuData symbol_menu;
 };
 
-#define LIBRARY_TOOLBAR_ICON_WIDTH 32
-
 
 /* ===== Local functions =================================================== */
 
 static void ld_window_main_finalize (GObject *gobject);
 
-static void load_library_toolbar (LdWindowMain *self);
-static void load_category_cb (gpointer data, gpointer user_data);
-static GdkPixbuf *recolor_pixbuf (GdkPixbuf *pbuf, GdkColor *color);
-
-static void redraw_symbol_menu (LdWindowMain *self);
-static void on_category_toggle (GtkToggleButton *toggle_button,
-	gpointer user_data);
-static gboolean on_canvas_exposed (GtkWidget *widget,
-	GdkEventExpose *event, gpointer user_data);
-static gboolean on_canvas_motion_notify (GtkWidget *widget,
-	GdkEventMotion *event, gpointer user_data);
-static gboolean on_canvas_button_press (GtkWidget *widget,
-	GdkEventButton *event, gpointer user_data);
-static gboolean on_canvas_button_release (GtkWidget *widget,
-	GdkEventButton *event, gpointer user_data);
-
 static void on_ui_proxy_connected (GtkUIManager *ui, GtkAction *action,
 	GtkWidget *proxy, LdWindowMain *window);
 static void on_ui_proxy_disconnected (GtkUIManager *ui, GtkAction *action,
@@ -143,6 +82,13 @@ static gboolean may_close_diagram (LdWindowMain *self,
 	const gchar *dialog_message);
 static gboolean may_quit (LdWindowMain *self);
 
+static void on_symbol_selected (LdLibraryToolbar *toolbar, LdSymbol *symbol,
+	const gchar *klass, LdWindowMain *self);
+static void on_symbol_deselected (LdLibraryToolbar *toolbar, LdSymbol *symbol,
+	const gchar *klass, LdWindowMain *self);
+static void on_symbol_chosen (LdLibraryToolbar *toolbar, LdSymbol *symbol,
+	const gchar *klass, LdWindowMain *self);
+
 static void on_action_new (GtkAction *action, LdWindowMain *self);
 static void on_action_open (GtkAction *action, LdWindowMain *self);
 static void on_action_save (GtkAction *action, LdWindowMain *self);
@@ -276,7 +222,7 @@ ld_window_main_init (LdWindowMain *self)
 	priv->toolbar = gtk_ui_manager_get_widget (priv->ui_manager, "/Toolbar");
 
 	/* Create the remaining widgets. */
-	priv->library_toolbar = gtk_toolbar_new ();
+	priv->library_toolbar = ld_library_toolbar_new ();
 	/* XXX: For GTK 2.16+, s/toolbar/orientable/ */
 	gtk_toolbar_set_orientation (GTK_TOOLBAR (priv->library_toolbar),
 		GTK_ORIENTATION_VERTICAL);
@@ -316,32 +262,6 @@ ld_window_main_init (LdWindowMain *self)
 	gtk_window_set_default_size (GTK_WINDOW (self), 500, 400);
 	gtk_window_set_position (GTK_WINDOW (self), GTK_WIN_POS_CENTER);
 
-	/* Hook canvas signals. */
-	/* XXX: To be able to draw a symbol menu over the canvas, we may:
-	 *   1. Hook the expose-event and button-{press,release}-event signals.
-	 *   2. Create a hook mechanism in the LdCanvas object.
-	 *     + The cairo context would not have to be created twice.
-	 *     - More complex API.
-	 */
-	priv->symbol_menu.expose_handler = g_signal_connect (priv->canvas,
-		"expose-event", G_CALLBACK (on_canvas_exposed), self);
-	priv->symbol_menu.motion_notify_handler = g_signal_connect (priv->canvas,
-		"motion-notify-event", G_CALLBACK (on_canvas_motion_notify), self);
-	priv->symbol_menu.button_press_handler = g_signal_connect (priv->canvas,
-		"button-press-event", G_CALLBACK (on_canvas_button_press), self);
-	priv->symbol_menu.button_release_handler = g_signal_connect (priv->canvas,
-		"button-release-event", G_CALLBACK (on_canvas_button_release), self);
-
-	/* Don't process the signals yet. */
-	g_signal_handler_block (priv->canvas,
-		priv->symbol_menu.expose_handler);
-	g_signal_handler_block (priv->canvas,
-		priv->symbol_menu.motion_notify_handler);
-	g_signal_handler_block (priv->canvas,
-		priv->symbol_menu.button_press_handler);
-	g_signal_handler_block (priv->canvas,
-		priv->symbol_menu.button_release_handler);
-
 	/* Initialize the backend. */
 	priv->diagram = ld_diagram_new ();
 
@@ -357,7 +277,18 @@ ld_window_main_init (LdWindowMain *self)
 	ld_canvas_set_diagram (priv->canvas, priv->diagram);
 	ld_canvas_set_library (priv->canvas, priv->library);
 
-	load_library_toolbar (self);
+	ld_library_toolbar_set_library (LD_LIBRARY_TOOLBAR (priv->library_toolbar),
+		priv->library);
+	ld_library_toolbar_set_canvas (LD_LIBRARY_TOOLBAR (priv->library_toolbar),
+		priv->canvas);
+
+	g_signal_connect_after (priv->library_toolbar, "symbol-selected",
+		G_CALLBACK (on_symbol_selected), self);
+	g_signal_connect_after (priv->library_toolbar, "symbol-deselected",
+		G_CALLBACK (on_symbol_deselected), self);
+	g_signal_connect_after (priv->library_toolbar, "symbol-chosen",
+		G_CALLBACK (on_symbol_chosen), self);
+
 	diagram_set_filename (self, NULL);
 
 	action_set_sensitive (self, "Export", FALSE);
@@ -372,11 +303,6 @@ ld_window_main_init (LdWindowMain *self)
 	gtk_widget_show_all (GTK_WIDGET (self));
 }
 
-/*
- * ld_window_main_finalize:
- *
- * Dispose of all the resources owned by this window.
- */
 static void
 ld_window_main_finalize (GObject *gobject)
 {
@@ -454,419 +380,6 @@ action_set_sensitive (LdWindowMain *self, const gchar *name, gboolean sensitive)
 }
 
 
-/* ===== Library toolbar and symbol menu =================================== */
-
-/*
- * load_library_toolbar:
- *
- * Load symbols from the library into the library toolbar.
- */
-static void
-load_library_toolbar (LdWindowMain *self)
-{
-	GSList *categories;
-
-	g_return_if_fail (LD_IS_WINDOW_MAIN (self));
-
-	/* Clear the toolbar first, if there was already something in it. */
-	gtk_container_foreach (GTK_CONTAINER (self->priv->library_toolbar),
-		(GtkCallback) gtk_widget_destroy, NULL);
-
-	categories = (GSList *) ld_library_get_children (self->priv->library);
-	g_slist_foreach (categories, load_category_cb, self);
-}
-
-/*
- * load_category_cb:
- *
- * A foreach callback for adding categories into the library toolbar.
- */
-static void
-load_category_cb (gpointer data, gpointer user_data)
-{
-	LdWindowMain *self;
-	LdSymbolCategory *cat;
-	const gchar *human_name;
-	GdkPixbuf *pbuf, *new_pbuf;
-	GtkWidget *img;
-	GtkToolItem *item;
-	GtkWidget *button;
-	GtkStyle *style;
-
-	g_return_if_fail (LD_IS_WINDOW_MAIN (user_data));
-	g_return_if_fail (LD_IS_SYMBOL_CATEGORY (data));
-
-	self = user_data;
-	cat = data;
-
-	pbuf = gdk_pixbuf_new_from_file_at_size	(ld_symbol_category_get_image_path
-		(cat), LIBRARY_TOOLBAR_ICON_WIDTH, -1, NULL);
-	g_return_if_fail (pbuf != NULL);
-
-	button = gtk_toggle_button_new ();
-	style = gtk_rc_get_style (button);
-
-	/* TODO: Handle all states. */
-	new_pbuf = recolor_pixbuf (pbuf, &style->fg[GTK_STATE_NORMAL]);
-	if (new_pbuf)
-	{
-		g_object_unref (pbuf);
-		pbuf = new_pbuf;
-	}
-
-	img = gtk_image_new_from_pixbuf (pbuf);
-	g_object_unref (pbuf);
-
-	item = gtk_tool_item_new ();
-	gtk_container_add (GTK_CONTAINER (button), img);
-	gtk_container_add (GTK_CONTAINER (item), button);
-
-	/* Don't steal focus from the canvas. */
-	g_object_set (button, "can-focus", FALSE, NULL);
-
-	/* Assign the category to the toggle button. */
-	g_object_ref (cat);
-	g_object_set_data_full (G_OBJECT (button),
-		"category", cat, (GDestroyNotify) g_object_unref);
-
-	/* Hook toggling of the button. */
-	g_signal_connect (button, "toggled", G_CALLBACK (on_category_toggle), self);
-
-	human_name = ld_symbol_category_get_human_name (cat);
-	gtk_tool_item_set_tooltip_text (item, human_name);
-	gtk_toolbar_insert (GTK_TOOLBAR (self->priv->library_toolbar), item, 0);
-}
-
-/*
- * recolor_pixbuf:
- *
- * Change the color of all pixels to @color,
- * but leave the alpha channel intact.
- */
-static GdkPixbuf *
-recolor_pixbuf (GdkPixbuf *pbuf, GdkColor *color)
-{
-	gint width, height;
-	GdkPixbuf *new_pbuf;
-	cairo_surface_t *cr_surface;
-	cairo_t *cr;
-
-	width  = gdk_pixbuf_get_width  (pbuf);
-	height = gdk_pixbuf_get_height (pbuf);
-
-	new_pbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, width, height);
-	g_return_val_if_fail (new_pbuf != NULL, NULL);
-
-	cr_surface = cairo_image_surface_create_for_data
-		(gdk_pixbuf_get_pixels (new_pbuf), CAIRO_FORMAT_ARGB32,
-		width, height, gdk_pixbuf_get_rowstride (new_pbuf));
-	cr = cairo_create (cr_surface);
-
-	gdk_cairo_set_source_color (cr, color);
-	cairo_paint (cr);
-
-	cairo_set_operator (cr, CAIRO_OPERATOR_DEST_IN);
-	gdk_cairo_set_source_pixbuf (cr, pbuf, 0, 0);
-	cairo_paint (cr);
-
-	cairo_destroy (cr);
-	cairo_surface_destroy (cr_surface);
-	return new_pbuf;
-}
-
-/*
- * redraw_symbol_menu:
- *
- * Make the area for symbol menu redraw itself.
- */
-static void
-redraw_symbol_menu (LdWindowMain *self)
-{
-	SymbolMenuData *data;
-
-	g_return_if_fail (LD_IS_WINDOW_MAIN (self));
-	data = &self->priv->symbol_menu;
-
-	gtk_widget_queue_draw_area (GTK_WIDGET (self->priv->canvas),
-		0, data->menu_y - 1, data->menu_width + 2, data->menu_height + 2);
-}
-
-/*
- * on_category_toggle:
- *
- * Show or hide a symbol menu.
- */
-static void
-on_category_toggle (GtkToggleButton *toggle_button, gpointer user_data)
-{
-	LdWindowMain *self;
-	LdWindowMainPrivate *priv;
-	LdSymbolCategory *cat;
-	SymbolMenuData *data;
-
-	cat = g_object_get_data (G_OBJECT (toggle_button), "category");
-	self = LD_WINDOW_MAIN (user_data);
-	priv = self->priv;
-	data = &priv->symbol_menu;
-
-	/* First untoggle any active button. */
-	if (data->active_button)
-		gtk_toggle_button_set_active (data->active_button, FALSE);
-
-	/* And toggle signal handlers that enable the user to add a symbol. */
-	if (data->active_button == toggle_button)
-	{
-		gint i;
-
-		g_signal_handler_block (priv->canvas,
-			priv->symbol_menu.expose_handler);
-		g_signal_handler_block (priv->canvas,
-			priv->symbol_menu.motion_notify_handler);
-		g_signal_handler_block (priv->canvas,
-			priv->symbol_menu.button_press_handler);
-		g_signal_handler_block (priv->canvas,
-			priv->symbol_menu.button_release_handler);
-
-		g_object_unref (data->active_button);
-		data->active_button = NULL;
-
-		/* Ashes to ashes, NULL to NULL. */
-		for (i = 0; i < data->n_items; i++)
-			g_object_unref (data->items[i].symbol);
-
-		g_free (data->items);
-		data->items = NULL;
-
-		gtk_statusbar_pop (GTK_STATUSBAR (self->priv->statusbar),
-			self->priv->statusbar_menu_context_id);
-
-		gtk_grab_remove (GTK_WIDGET (self->priv->canvas));
-	}
-	else
-	{
-		const GSList *children, *symbol_iter;
-		SymbolMenuItem *item;
-		gint x, y, menu_width;
-
-		g_return_if_fail (gtk_widget_translate_coordinates (GTK_WIDGET
-			(toggle_button), GTK_WIDGET (priv->canvas), 0, 0, &x, &y));
-
-		data->menu_y = y;
-		data->menu_height = GTK_WIDGET (toggle_button)->allocation.height;
-
-		g_signal_handler_unblock (priv->canvas,
-			priv->symbol_menu.expose_handler);
-		g_signal_handler_unblock (priv->canvas,
-			priv->symbol_menu.motion_notify_handler);
-		g_signal_handler_unblock (priv->canvas,
-			priv->symbol_menu.button_press_handler);
-		g_signal_handler_unblock (priv->canvas,
-			priv->symbol_menu.button_release_handler);
-
-		data->active_button = toggle_button;
-		g_object_ref (data->active_button);
-
-		children = ld_symbol_category_get_children (cat);
-
-		data->n_items = g_slist_length ((GSList *) children);
-		data->items = g_new (SymbolMenuItem, data->n_items);
-		data->active_item = -1;
-
-		item = data->items;
-		menu_width = 0;
-		for (symbol_iter = children; symbol_iter;
-			symbol_iter = symbol_iter->next)
-		{
-			LdRectangle area;
-
-			item->symbol = LD_SYMBOL (symbol_iter->data);
-			g_object_ref (item->symbol);
-
-			ld_symbol_get_area (item->symbol, &area);
-
-			/* This is the height when the center of the symbol is
-			 * in the center of it's symbol menu item.
-			 */
-			item->scale = data->menu_height * 0.5
-				/ MAX (ABS (area.y), ABS (area.y + area.height)) * 0.5;
-			item->width = data->menu_height * 0.5 + item->scale * area.width;
-			item->dx = item->width * 0.5 + item->scale * (area.width * 0.5
-				- MAX (ABS (area.x), ABS (area.x + area.width)));
-
-			menu_width += item++->width;
-		}
-		data->menu_width = menu_width;
-
-		gtk_grab_add (GTK_WIDGET (self->priv->canvas));
-	}
-	redraw_symbol_menu (self);
-}
-
-static gboolean
-on_canvas_exposed (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
-{
-	cairo_t *cr;
-	LdWindowMain *self;
-	SymbolMenuData *data;
-	gint i, x;
-
-	cr = gdk_cairo_create (widget->window);
-	self = LD_WINDOW_MAIN (user_data);
-	data = &self->priv->symbol_menu;
-
-	/* Draw some border. */
-	cairo_set_line_width (cr, 1);
-
-	cairo_rectangle (cr, 0, data->menu_y, data->menu_width, data->menu_height);
-	cairo_set_source_rgb (cr, 1, 1, 1);
-	cairo_fill (cr);
-
-	/* Draw all symbols from that category. */
-	for (x = i = 0; i < data->n_items; i++)
-	{
-		SymbolMenuItem *item;
-
-		item = data->items + i;
-		cairo_save (cr);
-
-		cairo_rectangle (cr, x, data->menu_y, item->width, data->menu_height);
-		cairo_clip (cr);
-
-		if (i == data->active_item)
-		{
-			cairo_set_source_rgb (cr, 0.9, 0.9, 0.9);
-			cairo_paint (cr);
-		}
-
-		cairo_translate (cr, x + item->dx,
-			data->menu_y + data->menu_height * 0.5);
-		cairo_scale (cr, item->scale, item->scale);
-
-		cairo_set_source_rgb (cr, 0, 0, 0);
-		cairo_set_line_width (cr, 1 / item->scale);
-		ld_symbol_draw (item->symbol, cr);
-
-		cairo_restore (cr);
-		x += item->width;
-	}
-
-	cairo_rectangle (cr, 0, data->menu_y, data->menu_width, data->menu_height);
-	cairo_set_source_rgb (cr, 0, 0, 0);
-	cairo_stroke (cr);
-
-	cairo_destroy (cr);
-	return FALSE;
-}
-
-static gboolean
-on_canvas_motion_notify (GtkWidget *widget, GdkEventMotion *event,
-	gpointer user_data)
-{
-	LdWindowMain *self;
-	SymbolMenuData *data;
-	gint i, x, at_cursor = -1;
-
-	self = LD_WINDOW_MAIN (user_data);
-	data = &self->priv->symbol_menu;
-
-	if (widget->window != event->window
-		|| event->x < 0 || event->y < data->menu_y
-		|| event->y >= data->menu_y + data->menu_height)
-		goto on_canvas_motion_notify_end;
-
-	for (x = i = 0; i < data->n_items; i++)
-	{
-		x += data->items[i].width;
-		if (event->x < x)
-		{
-			at_cursor = i;
-			break;
-		}
-	}
-
-on_canvas_motion_notify_end:
-	if (data->active_item != at_cursor)
-	{
-		const gchar *symbol_name;
-
-		gtk_statusbar_pop (GTK_STATUSBAR (self->priv->statusbar),
-			self->priv->statusbar_menu_context_id);
-
-		if (at_cursor != -1)
-		{
-			symbol_name = ld_symbol_get_human_name (data->items[i].symbol);
-			gtk_statusbar_push (GTK_STATUSBAR (self->priv->statusbar),
-				self->priv->statusbar_menu_context_id, symbol_name);
-		}
-	}
-	data->active_item = at_cursor;
-	redraw_symbol_menu (self);
-	return FALSE;
-}
-
-static gboolean
-on_canvas_button_press (GtkWidget *widget, GdkEventButton *event,
-	gpointer user_data)
-{
-	LdWindowMain *self;
-	SymbolMenuData *data;
-
-	self = LD_WINDOW_MAIN (user_data);
-	data = &self->priv->symbol_menu;
-
-	/* If the event occured elsewhere, cancel the menu and put the event
-	 * back into the queue.
-	 */
-	if (widget->window != event->window && data->active_button)
-	{
-		gtk_toggle_button_set_active (data->active_button, FALSE);
-		gdk_event_put ((GdkEvent *) event);
-	}
-	return FALSE;
-}
-
-static gboolean
-on_canvas_button_release (GtkWidget *widget, GdkEventButton *event,
-	gpointer user_data)
-{
-	LdWindowMain *self;
-	SymbolMenuData *data;
-
-	self = LD_WINDOW_MAIN (user_data);
-	data = &self->priv->symbol_menu;
-
-	if (event->button != 1)
-		return FALSE;
-
-	if (data->active_item != -1)
-	{
-		LdDiagramSymbol *symbol;
-		const gchar *category_name, *symbol_name;
-		gchar *klass;
-
-		category_name = ld_symbol_category_get_name
-			(g_object_get_data (G_OBJECT (data->active_button), "category"));
-		symbol_name = ld_symbol_get_name
-			(data->items[data->active_item].symbol);
-
-		klass = g_build_path (LD_LIBRARY_IDENTIFIER_SEPARATOR,
-			category_name, symbol_name, NULL);
-		symbol = ld_diagram_symbol_new (NULL);
-		ld_diagram_symbol_set_class (symbol, klass);
-		g_free (klass);
-
-		ld_canvas_add_object_begin (self->priv->canvas,
-			LD_DIAGRAM_OBJECT (symbol));
-	}
-
-	/* We've either chosen a symbol or canceled the menu, so hide it. */
-	if (data->active_button)
-		gtk_toggle_button_set_active (data->active_button, FALSE);
-
-	return FALSE;
-}
-
-
 /* ===== Menu items processing ============================================= */
 
 static void
@@ -1216,6 +729,38 @@ may_quit (LdWindowMain *self)
 /* ===== User interface actions ============================================ */
 
 static void
+on_symbol_selected (LdLibraryToolbar *toolbar, LdSymbol *symbol,
+	const gchar *klass, LdWindowMain *self)
+{
+	const gchar *symbol_name;
+
+	symbol_name = ld_symbol_get_human_name (symbol);
+	gtk_statusbar_push (GTK_STATUSBAR (self->priv->statusbar),
+		self->priv->statusbar_menu_context_id, symbol_name);
+}
+
+static void
+on_symbol_deselected (LdLibraryToolbar *toolbar, LdSymbol *symbol,
+	const gchar *klass, LdWindowMain *self)
+{
+	gtk_statusbar_pop (GTK_STATUSBAR (self->priv->statusbar),
+		self->priv->statusbar_menu_context_id);
+}
+
+static void
+on_symbol_chosen (LdLibraryToolbar *toolbar, LdSymbol *symbol,
+	const gchar *klass, LdWindowMain *self)
+{
+	LdDiagramSymbol *diagram_symbol;
+
+	diagram_symbol = ld_diagram_symbol_new (NULL);
+	ld_diagram_symbol_set_class (diagram_symbol, klass);
+
+	ld_canvas_add_object_begin (self->priv->canvas,
+		LD_DIAGRAM_OBJECT (diagram_symbol));
+}
+
+static void
 on_action_new (GtkAction *action, LdWindowMain *self)
 {
 	diagram_new (self);