Rename LdCanvas to LdDiagramView.

1 files changed, 0 insertions, 2340 deletions

diff --git a/liblogdiag/ld-canvas.c b/liblogdiag/ld-canvas.c
deleted file mode 100644
index 93c70a1..0000000
--- a/liblogdiag/ld-canvas.c
+++ /dev/null
@@ -1,2340 +0,0 @@
-/*
- * ld-canvas.c
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010 - 2011. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#include <math.h>
-#include <string.h>
-#include <gdk/gdkkeysyms.h>
-
-#include "liblogdiag.h"
-#include "config.h"
-
-
-/**
- * SECTION:ld-canvas
- * @short_description: A canvas
- * @see_also: #LdDiagram
- *
- * #LdCanvas displays and enables the user to manipulate with an #LdDiagram.
- */
-
-/* Milimetres per inch. */
-#define MM_PER_INCH 25.4
-/* The default screen resolution in DPI units. */
-#define DEFAULT_SCREEN_RESOLUTION 96
-
-/* The maximal, minimal and default values of zoom. */
-#define ZOOM_MIN 0.01
-#define ZOOM_MAX 100
-#define ZOOM_DEFAULT 1
-/* Multiplication factor for zooming. */
-#define ZOOM_STEP 1.4
-
-/* When drawing is requested, extend all sides of
- * the rectangle to be drawn by this number of pixels.
- */
-#define QUEUE_DRAW_EXTEND 3
-/* Cursor tolerance for object borders. */
-#define OBJECT_BORDER_TOLERANCE 3
-/* Tolerance on all sides of symbols for strokes. */
-#define SYMBOL_CLIP_TOLERANCE 5
-
-/* Size of a highlighted terminal. */
-#define TERMINAL_RADIUS 5
-/* Tolerance around terminal points. */
-#define TERMINAL_HOVER_TOLERANCE 8
-
-/*
- * OperationEnd:
- *
- * Called upon ending an operation.
- */
-typedef void (*OperationEnd) (LdCanvas *self);
-
-enum
-{
-	OPER_0,
-	OPER_ADD_OBJECT,
-	OPER_CONNECT,
-	OPER_SELECT,
-	OPER_MOVE_SELECTION
-};
-
-typedef struct _AddObjectData AddObjectData;
-typedef struct _ConnectData ConnectData;
-typedef struct _SelectData SelectData;
-typedef struct _MoveSelectionData MoveSelectionData;
-
-struct _AddObjectData
-{
-	LdDiagramObject *object;
-	gboolean visible;
-};
-
-struct _ConnectData
-{
-	LdDiagramConnection *connection;
-	LdPoint origin;
-};
-
-struct _SelectData
-{
-	LdPoint drag_last_pos;
-};
-
-struct _MoveSelectionData
-{
-	LdPoint move_origin;
-};
-
-enum
-{
-	COLOR_BASE,
-	COLOR_GRID,
-	COLOR_OBJECT,
-	COLOR_SELECTION,
-	COLOR_TERMINAL,
-	COLOR_COUNT
-};
-
-typedef struct _LdCanvasColor LdCanvasColor;
-
-struct _LdCanvasColor
-{
-	gdouble r;
-	gdouble g;
-	gdouble b;
-	gdouble a;
-};
-
-/*
- * LdCanvasPrivate:
- * @diagram: a diagram object assigned to this canvas as a model.
- * @library: a library object assigned to this canvas as a model.
- * @adjustment_h: an adjustment object for the horizontal axis, if any.
- * @adjustment_v: an adjustment object for the vertical axis, if any.
- * @x: the X coordinate of the center of view.
- * @y: the Y coordinate of the center of view.
- * @zoom: the current zoom of the canvas.
- * @terminal: position of the highlighted terminal.
- * @terminal_hovered: whether a terminal is hovered.
- * @drag_start_pos: position of the mouse pointer when dragging started.
- * @drag_operation: the operation to start when dragging starts.
- * @operation: the current operation.
- * @operation_data: data related to the current operation.
- * @operation_end: a callback to end the operation.
- * @palette: colors used by the widget.
- */
-struct _LdCanvasPrivate
-{
-	LdDiagram *diagram;
-	LdLibrary *library;
-
-	GtkAdjustment *adjustment_h;
-	GtkAdjustment *adjustment_v;
-
-	gdouble x;
-	gdouble y;
-	gdouble zoom;
-
-	LdPoint terminal;
-	gboolean terminal_hovered;
-
-	LdPoint drag_start_pos;
-	gint drag_operation;
-
-	gint operation;
-	union
-	{
-		AddObjectData add_object;
-		ConnectData connect;
-		SelectData select;
-		MoveSelectionData move_selection;
-	}
-	operation_data;
-	OperationEnd operation_end;
-
-	LdCanvasColor palette[COLOR_COUNT];
-};
-
-#define OPER_DATA(self, member) ((self)->priv->operation_data.member)
-#define COLOR_GET(self, name) (&(self)->priv->palette[name])
-
-/*
- * DrawData:
- * @self: our #LdCanvas.
- * @cr: a cairo context to draw on.
- * @exposed_rect: the area that is to be redrawn.
- * @scale: computed size of one diagram unit in pixels.
- */
-typedef struct _DrawData DrawData;
-
-struct _DrawData
-{
-	LdCanvas *self;
-	cairo_t *cr;
-	LdRectangle exposed_rect;
-	gdouble scale;
-};
-
-enum
-{
-	PROP_0,
-	PROP_DIAGRAM,
-	PROP_LIBRARY,
-	PROP_ZOOM
-};
-
-static void ld_canvas_get_property (GObject *object, guint property_id,
-	GValue *value, GParamSpec *pspec);
-static void ld_canvas_set_property (GObject *object, guint property_id,
-	const GValue *value, GParamSpec *pspec);
-static void ld_canvas_finalize (GObject *gobject);
-
-static void ld_canvas_real_set_scroll_adjustments
-	(LdCanvas *self, GtkAdjustment *horizontal, GtkAdjustment *vertical);
-static void on_adjustment_value_changed
-	(GtkAdjustment *adjustment, LdCanvas *self);
-static void on_size_allocate (GtkWidget *widget, GtkAllocation *allocation,
-	gpointer user_data);
-static void update_adjustments (LdCanvas *self);
-static void ld_canvas_real_move (LdCanvas *self, gdouble dx, gdouble dy);
-
-static void diagram_connect_signals (LdCanvas *self);
-static void diagram_disconnect_signals (LdCanvas *self);
-
-static gdouble ld_canvas_get_base_unit_in_px (GtkWidget *self);
-static gdouble ld_canvas_get_scale_in_px (LdCanvas *self);
-
-/* Helper functions. */
-static void ld_canvas_color_set (LdCanvasColor *color,
-	gdouble r, gdouble g, gdouble b, gdouble a);
-static void ld_canvas_color_apply (LdCanvasColor *color, cairo_t *cr);
-static guint32 ld_canvas_color_to_cairo_argb (LdCanvasColor *color);
-
-static gdouble point_to_line_segment_distance
-	(const LdPoint *point, const LdPoint *p1, const LdPoint *p2);
-
-/* Generic functions. */
-static gboolean object_hit_test (LdCanvas *self,
-	LdDiagramObject *object, const LdPoint *point);
-static gboolean get_object_clip_area (LdCanvas *self,
-	LdDiagramObject *object, LdRectangle *rect);
-
-static void move_object_to_point (LdCanvas *self, LdDiagramObject *object,
-	const LdPoint *point);
-static LdDiagramObject *get_object_at_point (LdCanvas *self,
-	const LdPoint *point);
-
-static void move_selection (LdCanvas *self, gdouble dx, gdouble dy);
-static gboolean is_object_selected (LdCanvas *self, LdDiagramObject *object);
-
-static void queue_draw (LdCanvas *self, LdRectangle *rect);
-static void queue_object_draw (LdCanvas *self, LdDiagramObject *object);
-
-/* Symbol terminals. */
-static void check_terminals (LdCanvas *self, const LdPoint *point);
-static void rotate_terminal (LdPoint *terminal, gint symbol_rotation);
-static void hide_terminals (LdCanvas *self);
-static void queue_terminal_draw (LdCanvas *self, LdPoint *terminal);
-
-/* Diagram symbol. */
-static gboolean symbol_hit_test (LdCanvas *self,
-	LdDiagramSymbol *symbol, const LdPoint *point);
-static gboolean get_symbol_clip_area (LdCanvas *self,
-	LdDiagramSymbol *symbol, LdRectangle *rect);
-
-static gboolean get_symbol_area (LdCanvas *self,
-	LdDiagramSymbol *symbol, LdRectangle *rect);
-static void rotate_symbol_area (LdRectangle *area, gint rotation);
-static void rotate_symbol (LdCanvas *self, LdDiagramSymbol *symbol);
-static LdSymbol *resolve_symbol (LdCanvas *self,
-	LdDiagramSymbol *diagram_symbol);
-
-/* Diagram connection. */
-static gboolean connection_hit_test (LdCanvas *self,
-	LdDiagramConnection *connection, const LdPoint *point);
-static gboolean get_connection_clip_area (LdCanvas *self,
-	LdDiagramConnection *connection, LdRectangle *rect);
-
-static gboolean get_connection_area (LdCanvas *self,
-	LdDiagramConnection *connection, LdRectangle *rect);
-
-/* Operations. */
-static void ld_canvas_real_cancel_operation (LdCanvas *self);
-static void oper_add_object_end (LdCanvas *self);
-
-static void oper_connect_begin (LdCanvas *self, const LdPoint *point);
-static void oper_connect_end (LdCanvas *self);
-static void oper_connect_motion (LdCanvas *self, const LdPoint *point);
-
-static void oper_select_begin (LdCanvas *self, const LdPoint *point);
-static void oper_select_end (LdCanvas *self);
-static void oper_select_get_rectangle (LdCanvas *self, LdRectangle *rect);
-static void oper_select_queue_draw (LdCanvas *self);
-static void oper_select_draw (GtkWidget *widget, DrawData *data);
-static void oper_select_motion (LdCanvas *self, const LdPoint *point);
-
-static void oper_move_selection_begin (LdCanvas *self, const LdPoint *point);
-static void oper_move_selection_end (LdCanvas *self);
-static void oper_move_selection_motion (LdCanvas *self, const LdPoint *point);
-
-/* Events, rendering. */
-static void simulate_motion (LdCanvas *self);
-static gboolean on_motion_notify (GtkWidget *widget, GdkEventMotion *event,
-	gpointer user_data);
-static gboolean on_leave_notify (GtkWidget *widget, GdkEventCrossing *event,
-	gpointer user_data);
-static gboolean on_button_press (GtkWidget *widget, GdkEventButton *event,
-	gpointer user_data);
-static gboolean on_button_release (GtkWidget *widget, GdkEventButton *event,
-	gpointer user_data);
-static gboolean on_scroll (GtkWidget *widget, GdkEventScroll *event,
-	gpointer user_data);
-
-static gboolean on_expose_event (GtkWidget *widget, GdkEventExpose *event,
-	gpointer user_data);
-static void draw_grid (GtkWidget *widget, DrawData *data);
-static void draw_diagram (GtkWidget *widget, DrawData *data);
-static void draw_terminal (GtkWidget *widget, DrawData *data);
-static void draw_object (LdDiagramObject *diagram_object, DrawData *data);
-static void draw_symbol (LdDiagramSymbol *diagram_symbol, DrawData *data);
-static void draw_connection (LdDiagramConnection *connection, DrawData *data);
-
-
-G_DEFINE_TYPE (LdCanvas, ld_canvas, GTK_TYPE_DRAWING_AREA);
-
-static void
-ld_canvas_class_init (LdCanvasClass *klass)
-{
-	GObjectClass *object_class;
-	GtkWidgetClass *widget_class;
-	GtkBindingSet *binding_set;
-	GParamSpec *pspec;
-
-	widget_class = GTK_WIDGET_CLASS (klass);
-
-	object_class = G_OBJECT_CLASS (klass);
-	object_class->get_property = ld_canvas_get_property;
-	object_class->set_property = ld_canvas_set_property;
-	object_class->finalize = ld_canvas_finalize;
-
-	klass->set_scroll_adjustments = ld_canvas_real_set_scroll_adjustments;
-	klass->cancel_operation = ld_canvas_real_cancel_operation;
-	klass->move = ld_canvas_real_move;
-
-	binding_set = gtk_binding_set_by_class (klass);
-	gtk_binding_entry_add_signal (binding_set, GDK_Escape, 0,
-		"cancel-operation", 0);
-	gtk_binding_entry_add_signal (binding_set, GDK_Left, 0,
-		"move", 2, G_TYPE_DOUBLE, (gdouble) -1, G_TYPE_DOUBLE, (gdouble) 0);
-	gtk_binding_entry_add_signal (binding_set, GDK_Right, 0,
-		"move", 2, G_TYPE_DOUBLE, (gdouble) 1, G_TYPE_DOUBLE, (gdouble) 0);
-	gtk_binding_entry_add_signal (binding_set, GDK_Up, 0,
-		"move", 2, G_TYPE_DOUBLE, (gdouble) 0, G_TYPE_DOUBLE, (gdouble) -1);
-	gtk_binding_entry_add_signal (binding_set, GDK_Down, 0,
-		"move", 2, G_TYPE_DOUBLE, (gdouble) 0, G_TYPE_DOUBLE, (gdouble) 1);
-
-/**
- * LdCanvas:diagram:
- *
- * The underlying #LdDiagram object of this canvas.
- */
-	pspec = g_param_spec_object ("diagram", "Diagram",
-		"The underlying diagram object of this canvas.",
-		LD_TYPE_DIAGRAM, G_PARAM_READWRITE);
-	g_object_class_install_property (object_class, PROP_DIAGRAM, pspec);
-
-/**
- * LdCanvas: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);
-
-/**
- * LdCanvas:zoom:
- *
- * The zoom of this canvas.
- */
-	pspec = g_param_spec_double ("zoom", "Zoom",
-		"The zoom of this canvas.",
-		ZOOM_MIN, ZOOM_MAX, ZOOM_DEFAULT, G_PARAM_READWRITE);
-	g_object_class_install_property (object_class, PROP_ZOOM, pspec);
-
-/**
- * LdCanvas::set-scroll-adjustments:
- * @self: an #LdCanvas object.
- * @horizontal: the horizontal #GtkAdjustment.
- * @vertical: the vertical #GtkAdjustment.
- *
- * Set scroll adjustments for the canvas.
- */
-	widget_class->set_scroll_adjustments_signal = g_signal_new
-		("set-scroll-adjustments", G_TYPE_FROM_CLASS (widget_class),
-		G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
-		G_STRUCT_OFFSET (LdCanvasClass, set_scroll_adjustments),
-		NULL, NULL,
-		ld_marshal_VOID__OBJECT_OBJECT,
-		G_TYPE_NONE, 2, GTK_TYPE_ADJUSTMENT, GTK_TYPE_ADJUSTMENT);
-
-/**
- * LdCanvas::cancel-operation:
- * @self: an #LdCanvas object.
- *
- * Cancel any current operation.
- */
-	klass->cancel_operation_signal = g_signal_new
-		("cancel-operation", G_TYPE_FROM_CLASS (klass),
-		G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
-		G_STRUCT_OFFSET (LdCanvasClass, cancel_operation), NULL, NULL,
-		g_cclosure_marshal_VOID__VOID,
-		G_TYPE_NONE, 0);
-
-/**
- * LdCanvas::move:
- * @self: an #LdCanvas object.
- * @dx: The difference by which to move on the horizontal axis.
- * @dy: The difference by which to move on the vertical axis.
- *
- * Move the selection, if any, or the document.
- */
-	klass->move_signal = g_signal_new
-		("move", G_TYPE_FROM_CLASS (klass),
-		G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
-		G_STRUCT_OFFSET (LdCanvasClass, move), NULL, NULL,
-		ld_marshal_VOID__DOUBLE_DOUBLE,
-		G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
-
-	g_type_class_add_private (klass, sizeof (LdCanvasPrivate));
-}
-
-static void
-ld_canvas_init (LdCanvas *self)
-{
-	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
-		(self, LD_TYPE_CANVAS, LdCanvasPrivate);
-
-	self->priv->x = 0;
-	self->priv->y = 0;
-	self->priv->zoom = ZOOM_DEFAULT;
-
-	ld_canvas_color_set (COLOR_GET (self, COLOR_BASE), 1, 1, 1, 1);
-	ld_canvas_color_set (COLOR_GET (self, COLOR_GRID), 0.5, 0.5, 0.5, 1);
-	ld_canvas_color_set (COLOR_GET (self, COLOR_OBJECT), 0, 0, 0, 1);
-	ld_canvas_color_set (COLOR_GET (self, COLOR_SELECTION), 1, 0, 0, 1);
-	ld_canvas_color_set (COLOR_GET (self, COLOR_TERMINAL), 1, 0.5, 0.5, 1);
-
-	g_signal_connect (self, "size-allocate",
-		G_CALLBACK (on_size_allocate), NULL);
-	g_signal_connect (self, "expose-event",
-		G_CALLBACK (on_expose_event), NULL);
-
-	g_signal_connect (self, "motion-notify-event",
-		G_CALLBACK (on_motion_notify), NULL);
-	g_signal_connect (self, "leave-notify-event",
-		G_CALLBACK (on_leave_notify), NULL);
-	g_signal_connect (self, "button-press-event",
-		G_CALLBACK (on_button_press), NULL);
-	g_signal_connect (self, "button-release-event",
-		G_CALLBACK (on_button_release), NULL);
-	g_signal_connect (self, "scroll-event",
-		G_CALLBACK (on_scroll), NULL);
-
-	g_object_set (self, "can-focus", TRUE, NULL);
-
-	gtk_widget_add_events (GTK_WIDGET (self),
-		GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK
-		| GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK
-		| GDK_LEAVE_NOTIFY_MASK);
-}
-
-static void
-ld_canvas_finalize (GObject *gobject)
-{
-	LdCanvas *self;
-
-	self = LD_CANVAS (gobject);
-
-	ld_canvas_real_set_scroll_adjustments (self, NULL, NULL);
-
-	if (self->priv->diagram)
-	{
-		diagram_disconnect_signals (self);
-		g_object_unref (self->priv->diagram);
-	}
-	if (self->priv->library)
-		g_object_unref (self->priv->library);
-
-	/* Chain up to the parent class. */
-	G_OBJECT_CLASS (ld_canvas_parent_class)->finalize (gobject);
-}
-
-static void
-ld_canvas_get_property (GObject *object, guint property_id,
-	GValue *value, GParamSpec *pspec)
-{
-	LdCanvas *self;
-
-	self = LD_CANVAS (object);
-	switch (property_id)
-	{
-	case PROP_DIAGRAM:
-		g_value_set_object (value, ld_canvas_get_diagram (self));
-		break;
-	case PROP_LIBRARY:
-		g_value_set_object (value, ld_canvas_get_library (self));
-		break;
-	case PROP_ZOOM:
-		g_value_set_double (value, ld_canvas_get_zoom (self));
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-	}
-}
-
-static void
-ld_canvas_set_property (GObject *object, guint property_id,
-	const GValue *value, GParamSpec *pspec)
-{
-	LdCanvas *self;
-
-	self = LD_CANVAS (object);
-	switch (property_id)
-	{
-	case PROP_DIAGRAM:
-		ld_canvas_set_diagram (self, LD_DIAGRAM (g_value_get_object (value)));
-		break;
-	case PROP_LIBRARY:
-		ld_canvas_set_library (self, LD_LIBRARY (g_value_get_object (value)));
-		break;
-	case PROP_ZOOM:
-		ld_canvas_set_zoom (self, g_value_get_double (value));
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-	}
-}
-
-static void
-ld_canvas_real_set_scroll_adjustments (LdCanvas *self,
-	GtkAdjustment *horizontal, GtkAdjustment *vertical)
-{
-	/* TODO: Infinite canvas. */
-	GtkWidget *widget;
-	gdouble scale;
-
-	widget = GTK_WIDGET (self);
-	scale = ld_canvas_get_scale_in_px (self);
-
-	if (horizontal != self->priv->adjustment_h)
-	{
-		if (self->priv->adjustment_h)
-		{
-			g_signal_handlers_disconnect_by_func (self->priv->adjustment_h,
-				on_adjustment_value_changed, self);
-			g_object_unref (self->priv->adjustment_h);
-
-			self->priv->adjustment_h = NULL;
-		}
-		if (horizontal)
-		{
-			g_object_ref (horizontal);
-			g_signal_connect (horizontal, "value-changed",
-				G_CALLBACK (on_adjustment_value_changed), self);
-
-			horizontal->upper = 100;
-			horizontal->lower = -100;
-			horizontal->step_increment = 0.5;
-			horizontal->page_increment = 5;
-			horizontal->page_size = widget->allocation.width / scale;
-			horizontal->value = -horizontal->page_size / 2;
-
-			self->priv->adjustment_h = horizontal;
-		}
-	}
-
-	if (vertical != self->priv->adjustment_v)
-	{
-		if (self->priv->adjustment_v)
-		{
-			g_signal_handlers_disconnect_by_func (self->priv->adjustment_v,
-				on_adjustment_value_changed, self);
-			g_object_unref (self->priv->adjustment_v);
-
-			self->priv->adjustment_v = NULL;
-		}
-		if (vertical)
-		{
-			g_object_ref (vertical);
-			g_signal_connect (vertical, "value-changed",
-				G_CALLBACK (on_adjustment_value_changed), self);
-
-			vertical->upper = 100;
-			vertical->lower = -100;
-			vertical->step_increment = 0.5;
-			vertical->page_increment = 5;
-			vertical->page_size = widget->allocation.height / scale;
-			vertical->value = -vertical->page_size / 2;
-
-			self->priv->adjustment_v = vertical;
-		}
-	}
-}
-
-static void
-on_adjustment_value_changed (GtkAdjustment *adjustment, LdCanvas *self)
-{
-	GtkWidget *widget;
-	gdouble scale;
-
-	widget = GTK_WIDGET (self);
-	scale = ld_canvas_get_scale_in_px (self);
-
-	if (adjustment == self->priv->adjustment_h)
-	{
-		self->priv->x = adjustment->value
-			+ widget->allocation.width / scale / 2;
-		gtk_widget_queue_draw (widget);
-	}
-	else if (adjustment == self->priv->adjustment_v)
-	{
-		self->priv->y = adjustment->value
-			+ widget->allocation.height / scale / 2;
-		gtk_widget_queue_draw (widget);
-	}
-}
-
-static void
-on_size_allocate (GtkWidget *widget, GtkAllocation *allocation,
-	gpointer user_data)
-{
-	LdCanvas *self;
-
-	self = LD_CANVAS (widget);
-
-	/* FIXME: If the new allocation is bigger, we may see more than
-	 *        what we're supposed to be able to see -> adjust X and Y.
-	 *
-	 *        If the visible area is so large that we simply must see more,
-	 *        let's disable the scrollbars in question.
-	 */
-	update_adjustments (self);
-}
-
-static void
-update_adjustments (LdCanvas *self)
-{
-	gdouble scale;
-
-	scale = ld_canvas_get_scale_in_px (self);
-
-	if (self->priv->adjustment_h)
-	{
-		self->priv->adjustment_h->page_size
-			= GTK_WIDGET (self)->allocation.width  / scale;
-		self->priv->adjustment_h->value
-			= self->priv->x - self->priv->adjustment_h->page_size / 2;
-		gtk_adjustment_changed (self->priv->adjustment_h);
-	}
-	if (self->priv->adjustment_v)
-	{
-		self->priv->adjustment_v->page_size
-			= GTK_WIDGET (self)->allocation.height / scale;
-		self->priv->adjustment_v->value
-			= self->priv->y - self->priv->adjustment_v->page_size / 2;
-		gtk_adjustment_changed (self->priv->adjustment_v);
-	}
-}
-
-static void
-ld_canvas_real_move (LdCanvas *self, gdouble dx, gdouble dy)
-{
-	LdDiagram *diagram;
-
-	diagram = self->priv->diagram;
-	if (!diagram)
-		return;
-
-	/* TODO: Check/move boundaries, also implement normal
-	 *       getters and setters for priv->x and priv->y.
-	 */
-	if (ld_diagram_get_selection (diagram))
-		move_selection (self, dx, dy);
-	else
-	{
-		self->priv->x += dx;
-		self->priv->y += dy;
-
-		simulate_motion (self);
-		update_adjustments (self);
-	}
-	gtk_widget_queue_draw (GTK_WIDGET (self));
-}
-
-
-/* ===== Generic interface etc. ============================================ */
-
-/**
- * ld_canvas_new:
- *
- * Create an instance.
- */
-GtkWidget *
-ld_canvas_new (void)
-{
-	return g_object_new (LD_TYPE_CANVAS, NULL);
-}
-
-/**
- * ld_canvas_set_diagram:
- * @self: an #LdCanvas object.
- * @diagram: the #LdDiagram to be assigned to the canvas.
- *
- * Assign an #LdDiagram object to the canvas.
- */
-void
-ld_canvas_set_diagram (LdCanvas *self, LdDiagram *diagram)
-{
-	g_return_if_fail (LD_IS_CANVAS (self));
-	g_return_if_fail (LD_IS_DIAGRAM (diagram));
-
-	if (self->priv->diagram)
-	{
-		diagram_disconnect_signals (self);
-		g_object_unref (self->priv->diagram);
-	}
-
-	self->priv->diagram = diagram;
-	diagram_connect_signals (self);
-	g_object_ref (diagram);
-
-	g_object_notify (G_OBJECT (self), "diagram");
-}
-
-/**
- * ld_canvas_get_diagram:
- * @self: an #LdCanvas object.
- *
- * Get the #LdDiagram object assigned to this canvas.
- * The reference count on the diagram is not incremented.
- */
-LdDiagram *
-ld_canvas_get_diagram (LdCanvas *self)
-{
-	g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
-	return self->priv->diagram;
-}
-
-static void
-diagram_connect_signals (LdCanvas *self)
-{
-	g_return_if_fail (LD_IS_DIAGRAM (self->priv->diagram));
-
-	g_signal_connect_swapped (self->priv->diagram, "changed",
-		G_CALLBACK (gtk_widget_queue_draw), self);
-	g_signal_connect_swapped (self->priv->diagram, "selection-changed",
-		G_CALLBACK (gtk_widget_queue_draw), self);
-}
-
-static void
-diagram_disconnect_signals (LdCanvas *self)
-{
-	g_return_if_fail (LD_IS_DIAGRAM (self->priv->diagram));
-
-	g_signal_handlers_disconnect_matched (self->priv->diagram,
-		G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA, 0, 0, NULL,
-		gtk_widget_queue_draw, self);
-}
-
-/**
- * ld_canvas_set_library:
- * @self: an #LdCanvas object.
- * @library: the #LdLibrary to be assigned to the canvas.
- *
- * Assign an #LdLibrary object to the canvas.
- */
-void
-ld_canvas_set_library (LdCanvas *self, LdLibrary *library)
-{
-	g_return_if_fail (LD_IS_CANVAS (self));
-	g_return_if_fail (LD_IS_LIBRARY (library));
-
-	if (self->priv->library)
-		g_object_unref (self->priv->library);
-
-	self->priv->library = library;
-	g_object_ref (library);
-
-	g_object_notify (G_OBJECT (self), "library");
-}
-
-/**
- * ld_canvas_get_library:
- * @self: an #LdCanvas object.
- *
- * Get the #LdLibrary object assigned to this canvas.
- * The reference count on the library is not incremented.
- */
-LdLibrary *
-ld_canvas_get_library (LdCanvas *self)
-{
-	g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
-	return self->priv->library;
-}
-
-/*
- * ld_canvas_get_base_unit_in_px:
- * @self: a #GtkWidget object to retrieve DPI from (indirectly).
- *
- * Return value: length of the base unit in pixels.
- */
-static gdouble
-ld_canvas_get_base_unit_in_px (GtkWidget *self)
-{
-	gdouble resolution;
-
-	g_return_val_if_fail (GTK_IS_WIDGET (self), 1);
-
-	resolution = gdk_screen_get_resolution (gtk_widget_get_screen (self));
-	if (resolution == -1)
-		resolution = DEFAULT_SCREEN_RESOLUTION;
-
-	/* XXX: It might look better if the unit was rounded to a whole number. */
-	return resolution / MM_PER_INCH * LD_CANVAS_BASE_UNIT_LENGTH;
-}
-
-/*
- * ld_canvas_get_scale_in_px:
- * @self: an #LdCanvas object.
- *
- * Return value: displayed length of the base unit in pixels.
- */
-static gdouble
-ld_canvas_get_scale_in_px (LdCanvas *self)
-{
-	g_return_val_if_fail (LD_IS_CANVAS (self), 1);
-
-	return ld_canvas_get_base_unit_in_px (GTK_WIDGET (self))
-		* self->priv->zoom;
-}
-
-/**
- * ld_canvas_widget_to_diagram_coords:
- * @self: an #LdCanvas object.
- * @wx: the X coordinate to be translated.
- * @wy: the Y coordinate to be translated.
- * @dx: (out): the translated X coordinate.
- * @dy: (out): the translated Y coordinate.
- *
- * Translate coordinates located inside the canvas window
- * into diagram coordinates.
- */
-void
-ld_canvas_widget_to_diagram_coords (LdCanvas *self,
-	gdouble wx, gdouble wy, gdouble *dx, gdouble *dy)
-{
-	GtkWidget *widget;
-	gdouble scale;
-
-	g_return_if_fail (LD_IS_CANVAS (self));
-	g_return_if_fail (dx != NULL);
-	g_return_if_fail (dy != NULL);
-
-	widget = GTK_WIDGET (self);
-	scale = ld_canvas_get_scale_in_px (self);
-
-	/* We know diagram coordinates of the center of the canvas, so we may
-	 * translate the given X and Y coordinates to this center and then scale
-	 * them by dividing them by the current scale.
-	 */
-	*dx = self->priv->x + (wx - (widget->allocation.width  * 0.5)) / scale;
-	*dy = self->priv->y + (wy - (widget->allocation.height * 0.5)) / scale;
-}
-
-/**
- * ld_canvas_diagram_to_widget_coords:
- * @self: an #LdCanvas object.
- * @dx: the X coordinate to be translated.
- * @dy: the Y coordinate to be translated.
- * @wx: (out): the translated X coordinate.
- * @wy: (out): the translated Y coordinate.
- *
- * Translate diagram coordinates into canvas coordinates.
- */
-void
-ld_canvas_diagram_to_widget_coords (LdCanvas *self,
-	gdouble dx, gdouble dy, gdouble *wx, gdouble *wy)
-{
-	GtkWidget *widget;
-	gdouble scale;
-
-	g_return_if_fail (LD_IS_CANVAS (self));
-	g_return_if_fail (wx != NULL);
-	g_return_if_fail (wy != NULL);
-
-	widget = GTK_WIDGET (self);
-	scale = ld_canvas_get_scale_in_px (self);
-
-	/* Just the reversal of ld_canvas_widget_to_diagram_coords(). */
-	*wx = scale * (dx - self->priv->x) + 0.5 * widget->allocation.width;
-	*wy = scale * (dy - self->priv->y) + 0.5 * widget->allocation.height;
-}
-
-/**
- * ld_canvas_get_zoom:
- * @self: an #LdCanvas object.
- *
- * Return value: zoom of the canvas.
- */
-gdouble
-ld_canvas_get_zoom (LdCanvas *self)
-{
-	g_return_val_if_fail (LD_IS_CANVAS (self), -1);
-	return self->priv->zoom;
-}
-
-/**
- * ld_canvas_set_zoom:
- * @self: an #LdCanvas object.
- * @zoom: the zoom.
- *
- * Set zoom of the canvas.
- */
-void
-ld_canvas_set_zoom (LdCanvas *self, gdouble zoom)
-{
-	gdouble clamped_zoom;
-
-	g_return_if_fail (LD_IS_CANVAS (self));
-
-	clamped_zoom = CLAMP (zoom, ZOOM_MIN, ZOOM_MAX);
-	if (self->priv->zoom == clamped_zoom)
-		return;
-
-	self->priv->zoom = clamped_zoom;
-
-	simulate_motion (self);
-	update_adjustments (self);
-	gtk_widget_queue_draw (GTK_WIDGET (self));
-
-	g_object_notify (G_OBJECT (self), "zoom");
-}
-
-/**
- * ld_canvas_can_zoom_in:
- * @self: an #LdCanvas object.
- *
- * Return value: %TRUE if the view can be zoomed in.
- */
-gboolean
-ld_canvas_can_zoom_in (LdCanvas *self)
-{
-	g_return_val_if_fail (LD_IS_CANVAS (self), FALSE);
-	return self->priv->zoom < ZOOM_MAX;
-}
-
-/**
- * ld_canvas_can_zoom_out:
- * @self: an #LdCanvas object.
- *
- * Return value: %TRUE if the view can be zoomed out.
- */
-gboolean
-ld_canvas_can_zoom_out (LdCanvas *self)
-{
-	g_return_val_if_fail (LD_IS_CANVAS (self), FALSE);
-	return self->priv->zoom > ZOOM_MIN;
-}
-
-/**
- * ld_canvas_zoom_in:
- * @self: an #LdCanvas object.
- *
- * Zoom the view in.
- */
-void
-ld_canvas_zoom_in (LdCanvas *self)
-{
-	g_return_if_fail (LD_IS_CANVAS (self));
-	ld_canvas_set_zoom (self, self->priv->zoom * ZOOM_STEP);
-}
-
-/**
- * ld_canvas_zoom_out:
- * @self: an #LdCanvas object.
- *
- * Zoom the view out.
- */
-void
-ld_canvas_zoom_out (LdCanvas *self)
-{
-	g_return_if_fail (LD_IS_CANVAS (self));
-	ld_canvas_set_zoom (self, self->priv->zoom / ZOOM_STEP);
-}
-
-
-/* ===== Helper functions ================================================== */
-
-static void
-ld_canvas_color_set (LdCanvasColor *color,
-	gdouble r, gdouble g, gdouble b, gdouble a)
-{
-	color->r = r;
-	color->g = g;
-	color->b = b;
-	color->a = a;
-}
-
-static void
-ld_canvas_color_apply (LdCanvasColor *color, cairo_t *cr)
-{
-	cairo_set_source_rgba (cr, color->r, color->g, color->b, color->a);
-}
-
-static guint32
-ld_canvas_color_to_cairo_argb (LdCanvasColor *color)
-{
-	return (guint) (color->a            * 255) << 24
-	     | (guint) (color->r * color->a * 255) << 16
-	     | (guint) (color->g * color->a * 255) << 8
-	     | (guint) (color->b * color->a * 255);
-}
-
-static gdouble
-point_to_line_segment_distance
-	(const LdPoint *point, const LdPoint *p1, const LdPoint *p2)
-{
-	gdouble dx, dy, u;
-
-	dx = p2->x - p1->x;
-	dy = p2->y - p1->y;
-
-	if (dx == 0. && dy == 0.)
-		return ld_point_distance (point, p1->x, p1->y);
-
-	/* Find projection of the point onto the line. */
-	u = ((point->x - p1->x) * dx + (point->y - p1->y) * dy)
-		/ (dx * dx + dy * dy);
-
-	/* The projection is beyond the line segment. */
-	if (u < 0.)
-		return ld_point_distance (point, p1->x, p1->y);
-	else if (u > 1.)
-		return ld_point_distance (point, p2->x, p2->y);
-
-	/* The projection is on the line segment. */
-	return ld_point_distance (point, p1->x + u * dx, p1->y + u * dy);
-}
-
-
-/* ===== Generic functions ================================================= */
-
-static gboolean
-object_hit_test (LdCanvas *self, LdDiagramObject *object, const LdPoint *point)
-{
-	if (LD_IS_DIAGRAM_SYMBOL (object))
-		return symbol_hit_test (self,
-			LD_DIAGRAM_SYMBOL (object), point);
-	if (LD_IS_DIAGRAM_CONNECTION (object))
-		return connection_hit_test (self,
-			LD_DIAGRAM_CONNECTION (object), point);
-	return FALSE;
-}
-
-static gboolean
-get_object_clip_area (LdCanvas *self,
-	LdDiagramObject *object, LdRectangle *rect)
-{
-	if (LD_IS_DIAGRAM_SYMBOL (object))
-		return get_symbol_clip_area (self,
-			LD_DIAGRAM_SYMBOL (object), rect);
-	if (LD_IS_DIAGRAM_CONNECTION (object))
-		return get_connection_clip_area (self,
-			LD_DIAGRAM_CONNECTION (object), rect);
-	return FALSE;
-}
-
-static void
-move_object_to_point (LdCanvas *self, LdDiagramObject *object,
-	const LdPoint *point)
-{
-	gdouble diagram_x, diagram_y;
-
-	ld_canvas_widget_to_diagram_coords (self,
-		point->x, point->y, &diagram_x, &diagram_y);
-	g_object_set (object,
-		"x", floor (diagram_x + 0.5),
-		"y", floor (diagram_y + 0.5),
-		NULL);
-}
-
-static LdDiagramObject *
-get_object_at_point (LdCanvas *self, const LdPoint *point)
-{
-	GList *objects, *iter;
-
-	/* Iterate from the top object downwards. */
-	objects = (GList *) ld_diagram_get_objects (self->priv->diagram);
-	for (iter = g_list_last (objects); iter; iter = g_list_previous (iter))
-	{
-		LdDiagramObject *object;
-
-		object = LD_DIAGRAM_OBJECT (iter->data);
-		if (object_hit_test (self, object, point))
-			return object;
-	}
-	return NULL;
-}
-
-static void
-move_selection (LdCanvas *self, gdouble dx, gdouble dy)
-{
-	LdDiagram *diagram;
-	GList *selection, *iter;
-
-	diagram = self->priv->diagram;
-	if (!diagram)
-		return;
-
-	selection = ld_diagram_get_selection (diagram);
-	if (!selection)
-		return;
-
-	ld_diagram_begin_user_action (diagram);
-	for (iter = selection; iter; iter = g_list_next (iter))
-	{
-		gdouble x, y;
-
-		g_object_get (iter->data, "x", &x, "y", &y, NULL);
-		x += dx;
-		y += dy;
-		g_object_set (iter->data, "x", x, "y", y, NULL);
-	}
-	ld_diagram_end_user_action (diagram);
-}
-
-static gboolean
-is_object_selected (LdCanvas *self, LdDiagramObject *object)
-{
-	return g_list_find (ld_diagram_get_selection (self->priv->diagram),
-		object) != NULL;
-}
-
-static void
-queue_draw (LdCanvas *self, LdRectangle *rect)
-{
-	LdRectangle area;
-
-	area = *rect;
-	ld_rectangle_extend (&area, QUEUE_DRAW_EXTEND);
-	gtk_widget_queue_draw_area (GTK_WIDGET (self),
-		area.x, area.y, area.width, area.height);
-}
-
-static void
-queue_object_draw (LdCanvas *self, LdDiagramObject *object)
-{
-	LdRectangle rect;
-
-	if (!get_object_clip_area (self, object, &rect))
-		return;
-	queue_draw (self, &rect);
-}
-
-
-/* ===== Symbol terminals ================================================== */
-
-static void
-check_terminals (LdCanvas *self, const LdPoint *point)
-{
-	GList *objects, *iter;
-	LdDiagramSymbol *closest_symbol = NULL;
-	gdouble closest_distance = TERMINAL_HOVER_TOLERANCE;
-	LdPoint closest_terminal;
-
-	objects = (GList *) ld_diagram_get_objects (self->priv->diagram);
-	for (iter = objects; iter; iter = g_list_next (iter))
-	{
-		gdouble object_x, object_y;
-		LdDiagramSymbol *diagram_symbol;
-		LdSymbol *symbol;
-		const LdPointArray *terminals;
-		guint i;
-		gint rotation;
-
-		if (!LD_IS_DIAGRAM_SYMBOL (iter->data))
-			continue;
-
-		diagram_symbol = LD_DIAGRAM_SYMBOL (iter->data);
-		symbol = resolve_symbol (self, diagram_symbol);
-		if (!symbol)
-			continue;
-
-		g_object_get (diagram_symbol, "x", &object_x, "y", &object_y,
-			"rotation", &rotation, NULL);
-
-		terminals = ld_symbol_get_terminals (symbol);
-		for (i = 0; i < terminals->length; i++)
-		{
-			LdPoint cur_term, widget_coords;
-			gdouble distance;
-
-			cur_term = terminals->points[i];
-			rotate_terminal (&cur_term, rotation);
-			cur_term.x += object_x;
-			cur_term.y += object_y;
-
-			ld_canvas_diagram_to_widget_coords (self,
-				cur_term.x, cur_term.y, &widget_coords.x, &widget_coords.y);
-			distance = ld_point_distance (&widget_coords, point->x, point->y);
-			if (distance <= closest_distance)
-			{
-				closest_symbol = diagram_symbol;
-				closest_distance = distance;
-				closest_terminal = cur_term;
-			}
-		}
-	}
-
-	hide_terminals (self);
-
-	if (closest_symbol)
-	{
-		self->priv->terminal_hovered = TRUE;
-		self->priv->terminal = closest_terminal;
-		queue_terminal_draw (self, &closest_terminal);
-	}
-}
-
-static void
-rotate_terminal (LdPoint *terminal, gint symbol_rotation)
-{
-	gdouble temp;
-
-	switch (symbol_rotation)
-	{
-	case LD_DIAGRAM_SYMBOL_ROTATION_90:
-		temp = terminal->y;
-		terminal->y = terminal->x;
-		terminal->x = -temp;
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_180:
-		terminal->y = -terminal->y;
-		terminal->x = -terminal->x;
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_270:
-		temp = terminal->x;
-		terminal->x = terminal->y;
-		terminal->y = -temp;
-		break;
-	}
-}
-
-static void
-hide_terminals (LdCanvas *self)
-{
-	if (self->priv->terminal_hovered)
-	{
-		self->priv->terminal_hovered = FALSE;
-		queue_terminal_draw (self, &self->priv->terminal);
-	}
-}
-
-static void
-queue_terminal_draw (LdCanvas *self, LdPoint *terminal)
-{
-	LdRectangle rect;
-	LdPoint widget_coords;
-
-	ld_canvas_diagram_to_widget_coords (self,
-		terminal->x, terminal->y, &widget_coords.x, &widget_coords.y);
-
-	rect.x = widget_coords.x - TERMINAL_RADIUS;
-	rect.y = widget_coords.y - TERMINAL_RADIUS;
-	rect.width  = 2 * TERMINAL_RADIUS;
-	rect.height = 2 * TERMINAL_RADIUS;
-
-	queue_draw (self, &rect);
-}
-
-
-/* ===== Diagram symbol ==================================================== */
-
-static gboolean
-symbol_hit_test (LdCanvas *self, LdDiagramSymbol *symbol, const LdPoint *point)
-{
-	LdRectangle rect;
-
-	if (!get_symbol_area (self, symbol, &rect))
-		return FALSE;
-	ld_rectangle_extend (&rect, OBJECT_BORDER_TOLERANCE);
-	return ld_rectangle_contains_point (&rect, point);
-}
-
-static gboolean
-get_symbol_clip_area (LdCanvas *self,
-	LdDiagramSymbol *symbol, LdRectangle *rect)
-{
-	LdRectangle object_rect;
-
-	if (!get_symbol_area (self, symbol, &object_rect))
-		return FALSE;
-
-	*rect = object_rect;
-	ld_rectangle_extend (rect, SYMBOL_CLIP_TOLERANCE);
-	return TRUE;
-}
-
-static gboolean
-get_symbol_area (LdCanvas *self, LdDiagramSymbol *symbol, LdRectangle *rect)
-{
-	gdouble object_x, object_y;
-	LdSymbol *library_symbol;
-	LdRectangle area;
-	gdouble x1, x2;
-	gdouble y1, y2;
-	gint rotation;
-
-	g_object_get (symbol, "x", &object_x, "y", &object_y,
-		"rotation", &rotation, NULL);
-
-	library_symbol = resolve_symbol (self, symbol);
-	if (library_symbol)
-		ld_symbol_get_area (library_symbol, &area);
-	else
-		return FALSE;
-
-	rotate_symbol_area (&area, rotation);
-
-	ld_canvas_diagram_to_widget_coords (self,
-		object_x + area.x,
-		object_y + area.y,
-		&x1, &y1);
-	ld_canvas_diagram_to_widget_coords (self,
-		object_x + area.x + area.width,
-		object_y + area.y + area.height,
-		&x2, &y2);
-
-	x1 = floor (x1);
-	y1 = floor (y1);
-	x2 = ceil (x2);
-	y2 = ceil (y2);
-
-	rect->x = x1;
-	rect->y = y1;
-	rect->width  = x2 - x1;
-	rect->height = y2 - y1;
-	return TRUE;
-}
-
-static void
-rotate_symbol_area (LdRectangle *area, gint rotation)
-{
-	gdouble temp;
-
-	switch (rotation)
-	{
-	case LD_DIAGRAM_SYMBOL_ROTATION_90:
-		temp = area->y;
-		area->y = area->x;
-		area->x = -(temp + area->height);
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_180:
-		area->y = -(area->y + area->height);
-		area->x = -(area->x + area->width);
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_270:
-		temp = area->x;
-		area->x = area->y;
-		area->y = -(temp + area->width);
-		break;
-	}
-
-	switch (rotation)
-	{
-	case LD_DIAGRAM_SYMBOL_ROTATION_90:
-	case LD_DIAGRAM_SYMBOL_ROTATION_270:
-		temp = area->width;
-		area->width = area->height;
-		area->height = temp;
-		break;
-	}
-}
-
-static void
-rotate_symbol (LdCanvas *self, LdDiagramSymbol *symbol)
-{
-	gint rotation;
-
-	g_object_get (symbol, "rotation", &rotation, NULL);
-	queue_object_draw (self, LD_DIAGRAM_OBJECT (symbol));
-
-	switch (rotation)
-	{
-	case LD_DIAGRAM_SYMBOL_ROTATION_0:
-		rotation = LD_DIAGRAM_SYMBOL_ROTATION_90;
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_90:
-		rotation = LD_DIAGRAM_SYMBOL_ROTATION_180;
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_180:
-		rotation = LD_DIAGRAM_SYMBOL_ROTATION_270;
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_270:
-		rotation = LD_DIAGRAM_SYMBOL_ROTATION_0;
-		break;
-	}
-
-	g_object_set (symbol, "rotation", rotation, NULL);
-	queue_object_draw (self, LD_DIAGRAM_OBJECT (symbol));
-}
-
-static LdSymbol *
-resolve_symbol (LdCanvas *self, LdDiagramSymbol *diagram_symbol)
-{
-	LdSymbol *symbol;
-	gchar *klass;
-
-	if (!self->priv->library)
-		return NULL;
-
-	klass = ld_diagram_symbol_get_class (diagram_symbol);
-	symbol = ld_library_find_symbol (self->priv->library, klass);
-	g_free (klass);
-	return symbol;
-}
-
-
-/* ===== Diagram connection ================================================ */
-
-static gboolean
-connection_hit_test (LdCanvas *self, LdDiagramConnection *connection,
-	const LdPoint *point)
-{
-	gdouble object_x, object_y, length;
-	LdPointArray *points;
-	guint i;
-
-	g_object_get (connection, "x", &object_x, "y", &object_y, NULL);
-
-	points = ld_diagram_connection_get_points (connection);
-	if (points->length < 2)
-	{
-		ld_point_array_free (points);
-		return FALSE;
-	}
-
-	for (i = 0; i < points->length; i++)
-	{
-		ld_canvas_diagram_to_widget_coords (self,
-			points->points[i].x + object_x,
-			points->points[i].y + object_y,
-			&points->points[i].x,
-			&points->points[i].y);
-
-		if (!i)
-			continue;
-
-		length = point_to_line_segment_distance
-			(point, &points->points[i - 1], &points->points[i]);
-		if (length <= OBJECT_BORDER_TOLERANCE)
-		{
-			ld_point_array_free (points);
-			return TRUE;
-		}
-	}
-	ld_point_array_free (points);
-	return FALSE;
-}
-
-static gboolean
-get_connection_clip_area (LdCanvas *self,
-	LdDiagramConnection *connection, LdRectangle *rect)
-{
-	return get_connection_area (self, connection, rect);
-}
-
-static gboolean
-get_connection_area (LdCanvas *self,
-	LdDiagramConnection *connection, LdRectangle *rect)
-{
-	gdouble x_origin, y_origin;
-	gdouble x, y, x_min, x_max, y_min, y_max;
-	LdPointArray *points;
-	guint i;
-
-	points = ld_diagram_connection_get_points (connection);
-	if (!points->length)
-	{
-		ld_point_array_free (points);
-		return FALSE;
-	}
-
-	g_object_get (connection, "x", &x_origin, "y", &y_origin, NULL);
-
-	ld_canvas_diagram_to_widget_coords (self,
-		x_origin + points->points[0].x,
-		y_origin + points->points[0].y,
-		&x, &y);
-
-	x_max = x_min = x;
-	y_max = y_min = y;
-
-	for (i = 1; i < points->length; i++)
-	{
-		ld_canvas_diagram_to_widget_coords (self,
-			x_origin + points->points[i].x,
-			y_origin + points->points[i].y,
-			&x, &y);
-
-		if (x < x_min)
-			x_min = x;
-		else if (x > x_max)
-			x_max = x;
-
-		if (y < y_min)
-			y_min = y;
-		else if (y > y_max)
-			y_max = y;
-	}
-
-	rect->x = x_min;
-	rect->y = y_min;
-	rect->width  = x_max - x_min;
-	rect->height = y_max - y_min;
-
-	ld_point_array_free (points);
-	return TRUE;
-}
-
-
-/* ===== Operations ======================================================== */
-
-static void
-ld_canvas_real_cancel_operation (LdCanvas *self)
-{
-	g_return_if_fail (LD_IS_CANVAS (self));
-
-	if (self->priv->operation)
-	{
-		if (self->priv->operation_end)
-			self->priv->operation_end (self);
-		self->priv->operation = OPER_0;
-		self->priv->operation_end = NULL;
-	}
-}
-
-/**
- * ld_canvas_add_object_begin:
- * @self: an #LdCanvas object.
- * @object: (transfer full): the object to be added to the diagram.
- *
- * Begin an operation for adding an object into the diagram.
- */
-void
-ld_canvas_add_object_begin (LdCanvas *self, LdDiagramObject *object)
-{
-	AddObjectData *data;
-
-	g_return_if_fail (LD_IS_CANVAS (self));
-	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (object));
-
-	g_signal_emit (self,
-		LD_CANVAS_GET_CLASS (self)->cancel_operation_signal, 0);
-
-	self->priv->operation = OPER_ADD_OBJECT;
-	self->priv->operation_end = oper_add_object_end;
-
-	data = &OPER_DATA (self, add_object);
-	data->object = object;
-}
-
-static void
-oper_add_object_end (LdCanvas *self)
-{
-	AddObjectData *data;
-
-	data = &OPER_DATA (self, add_object);
-	if (data->object)
-	{
-		queue_object_draw (self, data->object);
-		g_object_unref (data->object);
-		data->object = NULL;
-	}
-}
-
-static void
-oper_connect_begin (LdCanvas *self, const LdPoint *point)
-{
-	ConnectData *data;
-
-	g_signal_emit (self,
-		LD_CANVAS_GET_CLASS (self)->cancel_operation_signal, 0);
-
-	self->priv->operation = OPER_CONNECT;
-	self->priv->operation_end = oper_connect_end;
-
-	data = &OPER_DATA (self, connect);
-	data->connection = ld_diagram_connection_new (NULL);
-
-	data->origin = self->priv->terminal;
-	g_object_set (data->connection,
-		"x", data->origin.x,
-		"y", data->origin.y,
-		NULL);
-
-	self->priv->terminal_hovered = FALSE;
-
-	oper_connect_motion (self, point);
-}
-
-static void
-oper_connect_end (LdCanvas *self)
-{
-	ConnectData *data;
-
-	data = &OPER_DATA (self, connect);
-	queue_object_draw (self, LD_DIAGRAM_OBJECT (data->connection));
-
-	ld_diagram_insert_object (self->priv->diagram,
-		LD_DIAGRAM_OBJECT (data->connection), -1);
-
-	g_object_unref (data->connection);
-}
-
-static void
-oper_connect_motion (LdCanvas *self, const LdPoint *point)
-{
-	ConnectData *data;
-	LdPointArray *points;
-	gdouble diagram_x, diagram_y;
-
-	data = &OPER_DATA (self, connect);
-
-	/* Find an orthogonal path between the points. */
-	/* TODO: This alghorithm is pretty lame, needs to be improved. */
-	points = ld_point_array_sized_new (4);
-	points->length = 4;
-
-	points->points[0].x = 0;
-	points->points[0].y = 0;
-
-	ld_canvas_widget_to_diagram_coords (self,
-		point->x, point->y, &diagram_x, &diagram_y);
-	points->points[3].x = floor (diagram_x - data->origin.x + 0.5);
-	points->points[3].y = floor (diagram_y - data->origin.y + 0.5);
-
-	if (ABS (points->points[3].x) > ABS (points->points[3].y))
-	{
-		points->points[1].x = points->points[3].x / 2;
-		points->points[1].y = 0;
-		points->points[2].x = points->points[3].x / 2;
-		points->points[2].y = points->points[3].y;
-	}
-	else
-	{
-		points->points[1].x = 0;
-		points->points[1].y = points->points[3].y / 2;
-		points->points[2].x = points->points[3].x;
-		points->points[2].y = points->points[3].y / 2;
-	}
-
-	queue_object_draw (self, LD_DIAGRAM_OBJECT (data->connection));
-	ld_diagram_connection_set_points (data->connection, points);
-	queue_object_draw (self, LD_DIAGRAM_OBJECT (data->connection));
-	ld_point_array_free (points);
-
-	check_terminals (self, point);
-
-	if (self->priv->terminal.x == data->origin.x
-		&& self->priv->terminal.y == data->origin.y)
-		self->priv->terminal_hovered = FALSE;
-}
-
-static void
-oper_select_begin (LdCanvas *self, const LdPoint *point)
-{
-	SelectData *data;
-
-	g_signal_emit (self,
-		LD_CANVAS_GET_CLASS (self)->cancel_operation_signal, 0);
-
-	self->priv->operation = OPER_SELECT;
-	self->priv->operation_end = oper_select_end;
-
-	data = &OPER_DATA (self, select);
-	data->drag_last_pos.x = self->priv->drag_start_pos.x;
-	data->drag_last_pos.y = self->priv->drag_start_pos.y;
-
-	oper_select_motion (self, point);
-}
-
-static void
-oper_select_end (LdCanvas *self)
-{
-	oper_select_queue_draw (self);
-}
-
-static void
-oper_select_get_rectangle (LdCanvas *self, LdRectangle *rect)
-{
-	SelectData *data;
-
-	data = &OPER_DATA (self, select);
-	rect->x = MIN (self->priv->drag_start_pos.x, data->drag_last_pos.x);
-	rect->y = MIN (self->priv->drag_start_pos.y, data->drag_last_pos.y);
-	rect->width  = ABS (self->priv->drag_start_pos.x - data->drag_last_pos.x);
-	rect->height = ABS (self->priv->drag_start_pos.y - data->drag_last_pos.y);
-}
-
-static void
-oper_select_queue_draw (LdCanvas *self)
-{
-	LdRectangle rect;
-	SelectData *data;
-
-	data = &OPER_DATA (self, select);
-	oper_select_get_rectangle (self, &rect);
-	queue_draw (self, &rect);
-}
-
-static void
-oper_select_draw (GtkWidget *widget, DrawData *data)
-{
-	static const double dashes[] = {3, 5};
-	SelectData *select_data;
-
-	g_return_if_fail (data->self->priv->operation == OPER_SELECT);
-
-	ld_canvas_color_apply (COLOR_GET (data->self, COLOR_GRID), data->cr);
-	cairo_set_line_width (data->cr, 1);
-	cairo_set_line_cap (data->cr, CAIRO_LINE_CAP_SQUARE);
-	cairo_set_dash (data->cr, dashes, G_N_ELEMENTS (dashes), 0);
-
-	select_data = &OPER_DATA (data->self, select);
-
-	cairo_rectangle (data->cr,
-		data->self->priv->drag_start_pos.x - 0.5,
-		data->self->priv->drag_start_pos.y - 0.5,
-		select_data->drag_last_pos.x - data->self->priv->drag_start_pos.x + 1,
-		select_data->drag_last_pos.y - data->self->priv->drag_start_pos.y + 1);
-	cairo_stroke (data->cr);
-}
-
-static void
-oper_select_motion (LdCanvas *self, const LdPoint *point)
-{
-	SelectData *data;
-	GList *objects, *iter;
-	LdRectangle selection_rect, rect;
-
-	data = &OPER_DATA (self, select);
-
-	oper_select_queue_draw (self);
-	data->drag_last_pos = *point;
-	oper_select_queue_draw (self);
-
-	oper_select_get_rectangle (self, &selection_rect);
-	objects = (GList *) ld_diagram_get_objects (self->priv->diagram);
-
-	for (iter = objects; iter; iter = g_list_next (iter))
-	{
-		LdDiagramObject *object;
-
-		object = LD_DIAGRAM_OBJECT (iter->data);
-		if (LD_IS_DIAGRAM_SYMBOL (object))
-		{
-			if (!get_symbol_area (self,
-				LD_DIAGRAM_SYMBOL (object), &rect))
-				continue;
-		}
-		else if (LD_IS_DIAGRAM_CONNECTION (object))
-		{
-			if (!get_connection_area (self,
-				LD_DIAGRAM_CONNECTION (object), &rect))
-				continue;
-		}
-
-		ld_rectangle_extend (&rect, OBJECT_BORDER_TOLERANCE);
-		if (ld_rectangle_contains (&selection_rect, &rect))
-			ld_diagram_select (self->priv->diagram, object);
-		else
-			ld_diagram_unselect (self->priv->diagram, object);
-	}
-}
-
-static void
-oper_move_selection_begin (LdCanvas *self, const LdPoint *point)
-{
-	MoveSelectionData *data;
-
-	g_signal_emit (self,
-		LD_CANVAS_GET_CLASS (self)->cancel_operation_signal, 0);
-
-	self->priv->operation = OPER_MOVE_SELECTION;
-	self->priv->operation_end = oper_move_selection_end;
-
-	ld_diagram_begin_user_action (self->priv->diagram);
-
-	data = &OPER_DATA (self, move_selection);
-	data->move_origin = self->priv->drag_start_pos;
-
-	oper_move_selection_motion (self, point);
-}
-
-static void
-oper_move_selection_end (LdCanvas *self)
-{
-	ld_diagram_end_user_action (self->priv->diagram);
-}
-
-static void
-oper_move_selection_motion (LdCanvas *self, const LdPoint *point)
-{
-	MoveSelectionData *data;
-	gdouble scale, dx, dy, move_x, move_y;
-	gdouble move = FALSE;
-
-	scale = ld_canvas_get_scale_in_px (self);
-	data = &OPER_DATA (self, move_selection);
-
-	dx = point->x - data->move_origin.x;
-	dy = point->y - data->move_origin.y;
-
-	move_x = dx < 0 ? ceil (dx / scale) : floor (dx / scale);
-	move_y = dy < 0 ? ceil (dy / scale) : floor (dy / scale);
-
-	if (ABS (move_x) >= 1)
-	{
-		data->move_origin.x += move_x * scale;
-		move = TRUE;
-	}
-	if (ABS (move_y) >= 1)
-	{
-		data->move_origin.y += move_y * scale;
-		move = TRUE;
-	}
-
-	if (move)
-		move_selection (self, move_x, move_y);
-}
-
-
-/* ===== Events, rendering ================================================= */
-
-static void
-simulate_motion (LdCanvas *self)
-{
-	GdkEventMotion event;
-	GtkWidget *widget;
-	gint x, y;
-	GdkModifierType state;
-
-	widget = GTK_WIDGET (self);
-
-	if (gdk_window_get_pointer (widget->window, &x, &y, &state)
-		!= widget->window)
-		return;
-
-	memset (&event, 0, sizeof (event));
-	event.type = GDK_MOTION_NOTIFY;
-	event.window = widget->window;
-	event.x = x;
-	event.y = y;
-	event.state = state;
-
-	on_motion_notify (widget, &event, NULL);
-}
-
-static gboolean
-on_motion_notify (GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
-{
-	LdPoint point;
-	LdCanvas *self;
-	AddObjectData *add_data;
-
-	point.x = event->x;
-	point.y = event->y;
-
-	self = LD_CANVAS (widget);
-	switch (self->priv->operation)
-	{
-	case OPER_ADD_OBJECT:
-		add_data = &OPER_DATA (self, add_object);
-		add_data->visible = TRUE;
-
-		queue_object_draw (self, add_data->object);
-		move_object_to_point (self, add_data->object, &point);
-		queue_object_draw (self, add_data->object);
-		break;
-	case OPER_CONNECT:
-		oper_connect_motion (self, &point);
-		break;
-	case OPER_SELECT:
-		oper_select_motion (self, &point);
-		break;
-	case OPER_MOVE_SELECTION:
-		oper_move_selection_motion (self, &point);
-		break;
-	case OPER_0:
-		if (event->state & GDK_BUTTON1_MASK
-			&& (event->x != self->priv->drag_start_pos.x
-			|| event->y != self->priv->drag_start_pos.y))
-		{
-			switch (self->priv->drag_operation)
-			{
-			case OPER_CONNECT:
-				oper_connect_begin (self, &point);
-				break;
-			case OPER_SELECT:
-				oper_select_begin (self, &point);
-				break;
-			case OPER_MOVE_SELECTION:
-				oper_move_selection_begin (self, &point);
-				break;
-			}
-		}
-		check_terminals (self, &point);
-		break;
-	}
-	return FALSE;
-}
-
-static gboolean
-on_leave_notify (GtkWidget *widget, GdkEventCrossing *event, gpointer user_data)
-{
-	LdCanvas *self;
-
-	self = LD_CANVAS (widget);
-	switch (self->priv->operation)
-	{
-		AddObjectData *data;
-
-	case OPER_ADD_OBJECT:
-		data = &OPER_DATA (self, add_object);
-		data->visible = FALSE;
-
-		queue_object_draw (self, data->object);
-		break;
-	}
-	return FALSE;
-}
-
-static gboolean
-on_button_press (GtkWidget *widget, GdkEventButton *event, gpointer user_data)
-{
-	LdPoint point;
-	LdCanvas *self;
-	AddObjectData *data;
-	LdDiagramObject *object;
-
-	point.x = event->x;
-	point.y = event->y;
-
-	self = LD_CANVAS (widget);
-	if (!self->priv->diagram)
-		return FALSE;
-
-	if (event->button == 3 && self->priv->operation == OPER_0)
-	{
-		object = get_object_at_point (self, &point);
-		if (object && LD_IS_DIAGRAM_SYMBOL (object))
-			rotate_symbol (self, LD_DIAGRAM_SYMBOL (object));
-		return FALSE;
-	}
-
-	if (event->button != 1)
-		return FALSE;
-	if (!gtk_widget_has_focus (widget))
-		gtk_widget_grab_focus (widget);
-
-	self->priv->drag_operation = OPER_0;
-	switch (self->priv->operation)
-	{
-	case OPER_ADD_OBJECT:
-		data = &OPER_DATA (self, add_object);
-
-		queue_object_draw (self, data->object);
-		move_object_to_point (self, data->object, &point);
-		ld_diagram_insert_object (self->priv->diagram, data->object, -1);
-
-		/* XXX: "cancel" causes confusion. */
-		g_signal_emit (self,
-			LD_CANVAS_GET_CLASS (self)->cancel_operation_signal, 0);
-		break;
-	case OPER_0:
-		self->priv->drag_start_pos = point;
-
-		if (self->priv->terminal_hovered)
-		{
-			self->priv->drag_operation = OPER_CONNECT;
-			break;
-		}
-
-		object = get_object_at_point (self, &point);
-		if (!object)
-		{
-			ld_diagram_unselect_all (self->priv->diagram);
-			self->priv->drag_operation = OPER_SELECT;
-		}
-		else if (!is_object_selected (self, object))
-		{
-			if (event->state != GDK_SHIFT_MASK)
-				ld_diagram_unselect_all (self->priv->diagram);
-			ld_diagram_select (self->priv->diagram, object);
-			self->priv->drag_operation = OPER_MOVE_SELECTION;
-		}
-		else
-			self->priv->drag_operation = OPER_MOVE_SELECTION;
-		break;
-	}
-	return FALSE;
-}
-
-static gboolean
-on_button_release (GtkWidget *widget, GdkEventButton *event, gpointer user_data)
-{
-	LdPoint point;
-	LdCanvas *self;
-	LdDiagramObject *object;
-
-	if (event->button != 1)
-		return FALSE;
-
-	point.x = event->x;
-	point.y = event->y;
-
-	self = LD_CANVAS (widget);
-	if (!self->priv->diagram)
-		return FALSE;
-
-	switch (self->priv->operation)
-	{
-	case OPER_SELECT:
-	case OPER_MOVE_SELECTION:
-	case OPER_CONNECT:
-		g_signal_emit (self,
-			LD_CANVAS_GET_CLASS (self)->cancel_operation_signal, 0);
-		break;
-	case OPER_0:
-		object = get_object_at_point (self, &point);
-		if (object && is_object_selected (self, object))
-		{
-			if (!(event->state & GDK_SHIFT_MASK))
-				ld_diagram_unselect_all (self->priv->diagram);
-			ld_diagram_select (self->priv->diagram, object);
-		}
-		break;
-	}
-	return FALSE;
-}
-
-static gboolean
-on_scroll (GtkWidget *widget, GdkEventScroll *event, gpointer user_data)
-{
-	gdouble prev_x, prev_y;
-	gdouble new_x, new_y;
-	LdPoint point;
-	LdCanvas *self;
-
-	point.x = event->x;
-	point.y = event->y;
-	self = LD_CANVAS (widget);
-
-	ld_canvas_widget_to_diagram_coords (self,
-		event->x, event->y, &prev_x, &prev_y);
-
-	switch (event->direction)
-	{
-	case GDK_SCROLL_UP:
-		ld_canvas_zoom_in (self);
-		break;
-	case GDK_SCROLL_DOWN:
-		ld_canvas_zoom_out (self);
-		break;
-	default:
-		return FALSE;
-	}
-
-	ld_canvas_widget_to_diagram_coords (self,
-		event->x, event->y, &new_x, &new_y);
-
-	/* Focus on the point under the cursor. */
-	self->priv->x += prev_x - new_x;
-	self->priv->y += prev_y - new_y;
-
-	check_terminals (self, &point);
-	return TRUE;
-}
-
-static gboolean
-on_expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
-{
-	DrawData data;
-
-	data.cr = gdk_cairo_create (widget->window);
-	data.self = LD_CANVAS (widget);
-	data.scale = ld_canvas_get_scale_in_px (data.self);
-	data.exposed_rect.x = event->area.x;
-	data.exposed_rect.y = event->area.y;
-	data.exposed_rect.width = event->area.width;
-	data.exposed_rect.height = event->area.height;
-
-	gdk_cairo_rectangle (data.cr, &event->area);
-	cairo_clip (data.cr);
-
-	ld_canvas_color_apply (COLOR_GET (data.self, COLOR_BASE), data.cr);
-	cairo_paint (data.cr);
-
-	draw_grid (widget, &data);
-	draw_diagram (widget, &data);
-	draw_terminal (widget, &data);
-
-	if (data.self->priv->operation == OPER_SELECT)
-		oper_select_draw (widget, &data);
-
-	cairo_destroy (data.cr);
-	return FALSE;
-}
-
-static void
-draw_grid (GtkWidget *widget, DrawData *data)
-{
-	gdouble grid_step;
-	gint grid_factor;
-	gdouble x_init, y_init;
-	gdouble x, y;
-	cairo_surface_t *grid_surface;
-	gint stride;
-	unsigned char *pixels;
-	guint32 color;
-
-	grid_step = data->scale;
-	grid_factor = 1;
-	while (grid_step < 5)
-	{
-		grid_step *= 5;
-		grid_factor *= 5;
-	}
-
-	/* Paint manually on our own raster surface for speed. */
-	stride = cairo_format_stride_for_width
-		(CAIRO_FORMAT_ARGB32, data->exposed_rect.width);
-	pixels = g_malloc0 (stride * data->exposed_rect.height);
-	grid_surface = cairo_image_surface_create_for_data
-		(pixels, CAIRO_FORMAT_ARGB32,
-		data->exposed_rect.width, data->exposed_rect.height, stride);
-
-	/* Get coordinates of the top-left point. */
-	ld_canvas_widget_to_diagram_coords (data->self,
-		data->exposed_rect.x, data->exposed_rect.y, &x_init, &y_init);
-
-	x_init = ceil (x_init);
-	x_init = x_init - (gint) x_init % grid_factor;
-	y_init = ceil (y_init);
-	y_init = y_init - (gint) y_init % grid_factor;
-
-	ld_canvas_diagram_to_widget_coords (data->self,
-		x_init, y_init, &x_init, &y_init);
-
-	x_init -= data->exposed_rect.x;
-	y_init -= data->exposed_rect.y;
-
-	while (x_init < 0)
-		x_init += grid_step;
-	while (y_init < 0)
-		y_init += grid_step;
-
-	color = ld_canvas_color_to_cairo_argb (COLOR_GET (data->self, COLOR_GRID));
-
-	for     (x = x_init; x < data->exposed_rect.width;  x += grid_step)
-		for (y = y_init; y < data->exposed_rect.height; y += grid_step)
-			*((guint32 *) (pixels + stride * (gint) y) + (gint) x) = color;
-
-	cairo_set_source_surface (data->cr, grid_surface,
-		data->exposed_rect.x, data->exposed_rect.y);
-	cairo_paint (data->cr);
-
-	cairo_surface_destroy (grid_surface);
-	g_free (pixels);
-}
-
-static void
-draw_terminal (GtkWidget *widget, DrawData *data)
-{
-	LdCanvasPrivate *priv;
-	LdPoint widget_coords;
-
-	priv = data->self->priv;
-	if (!priv->terminal_hovered)
-		return;
-
-	ld_canvas_color_apply (COLOR_GET (data->self, COLOR_TERMINAL), data->cr);
-	cairo_set_line_width (data->cr, 1);
-
-	cairo_new_path (data->cr);
-	ld_canvas_diagram_to_widget_coords (data->self,
-		priv->terminal.x, priv->terminal.y,
-		&widget_coords.x, &widget_coords.y);
-	cairo_arc (data->cr, widget_coords.x, widget_coords.y,
-		TERMINAL_RADIUS, 0, 2 * G_PI);
-	cairo_stroke (data->cr);
-}
-
-static void
-draw_diagram (GtkWidget *widget, DrawData *data)
-{
-	GList *objects, *iter;
-
-	if (!data->self->priv->diagram)
-		return;
-
-	cairo_save (data->cr);
-	cairo_set_line_width (data->cr, 1 / data->scale);
-
-	/* Draw objects from the diagram, from bottom to top. */
-	objects = (GList *) ld_diagram_get_objects (data->self->priv->diagram);
-	for (iter = objects; iter; iter = g_list_next (iter))
-		draw_object (LD_DIAGRAM_OBJECT (iter->data), data);
-
-	switch (data->self->priv->operation)
-	{
-		AddObjectData *add_data;
-		ConnectData *connect_data;
-
-	case OPER_ADD_OBJECT:
-		add_data = &OPER_DATA (data->self, add_object);
-		if (add_data->visible)
-			draw_object (add_data->object, data);
-		break;
-	case OPER_CONNECT:
-		connect_data = &OPER_DATA (data->self, connect);
-		draw_object (LD_DIAGRAM_OBJECT (connect_data->connection), data);
-		break;
-	}
-
-	cairo_restore (data->cr);
-}
-
-static void
-draw_object (LdDiagramObject *diagram_object, DrawData *data)
-{
-	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (diagram_object));
-	g_return_if_fail (data != NULL);
-
-	if (is_object_selected (data->self, diagram_object))
-		ld_canvas_color_apply (COLOR_GET (data->self,
-			COLOR_SELECTION), data->cr);
-	else
-		ld_canvas_color_apply (COLOR_GET (data->self,
-			COLOR_OBJECT), data->cr);
-
-	if (LD_IS_DIAGRAM_SYMBOL (diagram_object))
-		draw_symbol (LD_DIAGRAM_SYMBOL (diagram_object), data);
-	else if (LD_IS_DIAGRAM_CONNECTION (diagram_object))
-		draw_connection (LD_DIAGRAM_CONNECTION (diagram_object), data);
-}
-
-static void
-draw_symbol (LdDiagramSymbol *diagram_symbol, DrawData *data)
-{
-	LdSymbol *symbol;
-	LdRectangle clip_rect;
-	gdouble x, y;
-	gint rotation;
-
-	symbol = resolve_symbol (data->self, diagram_symbol);
-
-	/* TODO: Resolve this better; draw a cross or whatever. */
-	if (!symbol)
-	{
-		gchar *klass;
-
-		klass = ld_diagram_symbol_get_class (diagram_symbol);
-		g_warning ("cannot find symbol `%s' in the library", klass);
-		g_free (klass);
-		return;
-	}
-
-	if (!get_symbol_clip_area (data->self, diagram_symbol, &clip_rect)
-		|| !ld_rectangle_intersects (&clip_rect, &data->exposed_rect))
-		return;
-
-	cairo_save (data->cr);
-
-	cairo_rectangle (data->cr, clip_rect.x, clip_rect.y,
-		clip_rect.width, clip_rect.height);
-	cairo_clip (data->cr);
-
-	g_object_get (diagram_symbol, "x", &x, "y", &y,
-		"rotation", &rotation, NULL);
-	ld_canvas_diagram_to_widget_coords (data->self, x, y, &x, &y);
-	cairo_translate (data->cr, x, y);
-	cairo_scale (data->cr, data->scale, data->scale);
-
-	switch (rotation)
-	{
-	case LD_DIAGRAM_SYMBOL_ROTATION_90:
-		cairo_rotate (data->cr, G_PI * 0.5);
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_180:
-		cairo_rotate (data->cr, G_PI);
-		break;
-	case LD_DIAGRAM_SYMBOL_ROTATION_270:
-		cairo_rotate (data->cr, G_PI * 1.5);
-		break;
-	}
-
-	ld_symbol_draw (symbol, data->cr);
-	cairo_restore (data->cr);
-}
-
-static void
-draw_connection (LdDiagramConnection *connection, DrawData *data)
-{
-	LdRectangle clip_rect;
-	LdPointArray *points;
-	gdouble x, y;
-	guint i;
-
-	if (!get_connection_clip_area (data->self, connection, &clip_rect)
-		|| !ld_rectangle_intersects (&clip_rect, &data->exposed_rect))
-		return;
-
-	points = ld_diagram_connection_get_points (connection);
-	if (points->length < 2)
-		goto draw_connection_end;
-
-	cairo_save (data->cr);
-
-	g_object_get (connection, "x", &x, "y", &y, NULL);
-	ld_canvas_diagram_to_widget_coords (data->self, x, y, &x, &y);
-	cairo_translate (data->cr, x, y);
-	cairo_scale (data->cr, data->scale, data->scale);
-
-	for (i = 1; i < points->length; i++)
-	{
-		cairo_move_to (data->cr,
-			points->points[i - 1].x,
-			points->points[i - 1].y);
-		cairo_line_to (data->cr,
-			points->points[i].x,
-			points->points[i].y);
-		cairo_stroke (data->cr);
-	}
-	cairo_restore (data->cr);
-
-draw_connection_end:
-	ld_point_array_free (points);
-	return;
-}