Rename LdDocument* to LdDiagram*.

My bad; this name is much more appropriate.

17 files changed, 1066 insertions, 1065 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 694b38a..52221d2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -89,9 +89,9 @@ set (logdiag_SOURCES
 	src/logdiag.c
 	src/ld-marshal.c
 	src/ld-window-main.c
-	src/ld-document.c
-	src/ld-document-object.c
-	src/ld-document-symbol.c
+	src/ld-diagram.c
+	src/ld-diagram-object.c
+	src/ld-diagram-symbol.c
 	src/ld-canvas.c
 	src/ld-library.c
 	src/ld-symbol-category.c
@@ -102,9 +102,9 @@ set (logdiag_HEADERS
 	${CMAKE_CURRENT_BINARY_DIR}/config.h
 	src/ld-marshal.h
 	src/ld-window-main.h
-	src/ld-document.h
-	src/ld-document-object.h
-	src/ld-document-symbol.h
+	src/ld-diagram.h
+	src/ld-diagram-object.h
+	src/ld-diagram-symbol.h
 	src/ld-canvas.h
 	src/ld-library.h
 	src/ld-symbol-category.h
diff --git a/src/ld-canvas.c b/src/ld-canvas.c
index 07d7a51..bc93902 100644
--- a/src/ld-canvas.c
+++ b/src/ld-canvas.c
@@ -14,9 +14,9 @@
 #include "config.h"
 
 #include "ld-marshal.h"
-#include "ld-document-object.h"
-#include "ld-document-symbol.h"
-#include "ld-document.h"
+#include "ld-diagram-object.h"
+#include "ld-diagram-symbol.h"
+#include "ld-diagram.h"
 #include "ld-symbol.h"
 #include "ld-library.h"
 #include "ld-canvas.h"
@@ -25,9 +25,9 @@
 /**
  * SECTION:ld-canvas
  * @short_description: A canvas.
- * @see_also: #LdDocument
+ * @see_also: #LdDiagram
  *
- * #LdCanvas is used for displaying #LdDocument objects.
+ * #LdCanvas is used for displaying #LdDiagram objects.
  */
 
 /* Milimetres per inch. */
@@ -38,7 +38,7 @@
 
 /*
  * LdCanvasPrivate:
- * @document: A document object assigned to this canvas as a model.
+ * @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.
@@ -48,7 +48,7 @@
  */
 struct _LdCanvasPrivate
 {
-	LdDocument *document;
+	LdDiagram *diagram;
 	LdLibrary *library;
 
 	GtkAdjustment *adjustment_h;
@@ -64,7 +64,7 @@ G_DEFINE_TYPE (LdCanvas, ld_canvas, GTK_TYPE_DRAWING_AREA);
 enum
 {
 	PROP_0,
-	PROP_DOCUMENT,
+	PROP_DIAGRAM,
 	PROP_LIBRARY
 };
 
@@ -75,7 +75,7 @@ typedef struct _DrawData 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 document unit in pixels.
+ * @scale: Computed size of one diagram unit in pixels.
  */
 struct _DrawData
 {
@@ -104,9 +104,9 @@ static void on_size_allocate (GtkWidget *widget, GtkAllocation *allocation,
 static gboolean on_expose_event (GtkWidget *widget, GdkEventExpose *event,
 	gpointer user_data);
 static void draw_grid (GtkWidget *widget, DrawData *data);
-static void draw_document (GtkWidget *widget, DrawData *data);
-static void draw_document_cb (gpointer link_data, DrawData *data);
-static void draw_symbol (LdDocumentSymbol *document_symbol, DrawData *data);
+static void draw_diagram (GtkWidget *widget, DrawData *data);
+static void draw_diagram_cb (gpointer link_data, DrawData *data);
+static void draw_symbol (LdDiagramSymbol *diagram_symbol, DrawData *data);
 
 
 static void
@@ -126,14 +126,14 @@ ld_canvas_class_init (LdCanvasClass *klass)
 	klass->set_scroll_adjustments = ld_canvas_real_set_scroll_adjustments;
 
 /**
- * LdCanvas:document:
+ * LdCanvas:diagram:
  *
- * The underlying #LdDocument object of this canvas.
+ * The underlying #LdDiagram object of this canvas.
  */
-	pspec = g_param_spec_object ("document", "Document",
-		"The underlying document object of this canvas.",
-		LD_TYPE_DOCUMENT, G_PARAM_READWRITE);
-	g_object_class_install_property (object_class, PROP_DOCUMENT, pspec);
+	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:
@@ -143,7 +143,7 @@ ld_canvas_class_init (LdCanvasClass *klass)
 	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_DOCUMENT, pspec);
+	g_object_class_install_property (object_class, PROP_DIAGRAM, pspec);
 
 /**
  * LdCanvas::set-scroll-adjustments:
@@ -192,8 +192,8 @@ ld_canvas_finalize (GObject *gobject)
 
 	ld_canvas_real_set_scroll_adjustments (self, NULL, NULL);
 
-	if (self->priv->document)
-		g_object_unref (self->priv->document);
+	if (self->priv->diagram)
+		g_object_unref (self->priv->diagram);
 	if (self->priv->library)
 		g_object_unref (self->priv->library);
 
@@ -210,8 +210,8 @@ ld_canvas_get_property (GObject *object, guint property_id,
 	self = LD_CANVAS (object);
 	switch (property_id)
 	{
-	case PROP_DOCUMENT:
-		g_value_set_object (value, ld_canvas_get_document (self));
+	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));
@@ -230,8 +230,8 @@ ld_canvas_set_property (GObject *object, guint property_id,
 	self = LD_CANVAS (object);
 	switch (property_id)
 	{
-	case PROP_DOCUMENT:
-		ld_canvas_set_document (self, LD_DOCUMENT (g_value_get_object (value)));
+	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)));
@@ -375,39 +375,39 @@ ld_canvas_new (void)
 }
 
 /**
- * ld_canvas_set_document:
+ * ld_canvas_set_diagram:
  * @self: An #LdCanvas object.
- * @document: The #LdDocument to be assigned to the canvas.
+ * @diagram: The #LdDiagram to be assigned to the canvas.
  *
- * Assign an #LdDocument object to the canvas.
+ * Assign an #LdDiagram object to the canvas.
  */
 void
-ld_canvas_set_document (LdCanvas *self, LdDocument *document)
+ld_canvas_set_diagram (LdCanvas *self, LdDiagram *diagram)
 {
 	g_return_if_fail (LD_IS_CANVAS (self));
-	g_return_if_fail (LD_IS_DOCUMENT (document));
+	g_return_if_fail (LD_IS_DIAGRAM (diagram));
 
-	if (self->priv->document)
-		g_object_unref (self->priv->document);
+	if (self->priv->diagram)
+		g_object_unref (self->priv->diagram);
 
-	self->priv->document = document;
-	g_object_ref (document);
+	self->priv->diagram = diagram;
+	g_object_ref (diagram);
 
-	g_object_notify (G_OBJECT (self), "document");
+	g_object_notify (G_OBJECT (self), "diagram");
 }
 
 /**
- * ld_canvas_get_document:
+ * ld_canvas_get_diagram:
  * @self: An #LdCanvas object.
  *
- * Get the #LdDocument object assigned to this canvas.
- * The reference count on the document is not incremented.
+ * Get the #LdDiagram object assigned to this canvas.
+ * The reference count on the diagram is not incremented.
  */
-LdDocument *
-ld_canvas_get_document (LdCanvas *self)
+LdDiagram *
+ld_canvas_get_diagram (LdCanvas *self)
 {
 	g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
-	return self->priv->document;
+	return self->priv->diagram;
 }
 
 /**
@@ -484,7 +484,7 @@ ld_canvas_get_scale_in_px (LdCanvas *self)
  * @y: The Y coordinate to be translated.
  *
  * Translate coordinates located inside the canvas window
- * into document coordinates.
+ * into diagram coordinates.
  */
 void
 ld_canvas_translate_canvas_coordinates (LdCanvas *self, gdouble *x, gdouble *y)
@@ -497,7 +497,7 @@ ld_canvas_translate_canvas_coordinates (LdCanvas *self, gdouble *x, gdouble *y)
 	widget = GTK_WIDGET (self);
 	scale = ld_canvas_get_scale_in_px (self);
 
-	/* We know document coordinates of the center of the canvas, so we may
+	/* 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 length of the base unit in pixels
 	 * times zoom of the canvas.
@@ -507,15 +507,15 @@ ld_canvas_translate_canvas_coordinates (LdCanvas *self, gdouble *x, gdouble *y)
 }
 
 /**
- * ld_canvas_translate_document_coordinates:
+ * ld_canvas_translate_diagram_coordinates:
  * @self: An #LdCanvas object.
  * @x: The X coordinate to be translated.
  * @y: The Y coordinate to be translated.
  *
- * Translate document coordinates into canvas coordinates.
+ * Translate diagram coordinates into canvas coordinates.
  */
 void
-ld_canvas_translate_document_coordinates (LdCanvas *self,
+ld_canvas_translate_diagram_coordinates (LdCanvas *self,
 	gdouble *x, gdouble *y)
 {
 	GtkWidget *widget;
@@ -553,7 +553,7 @@ on_expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 	cairo_paint (data.cr);
 
 	draw_grid (widget, &data);
-	draw_document (widget, &data);
+	draw_diagram (widget, &data);
 
 	cairo_destroy (data.cr);
 	return FALSE;
@@ -575,7 +575,7 @@ draw_grid (GtkWidget *widget, DrawData *data)
 	ld_canvas_translate_canvas_coordinates (data->self, &x_top, &y_top);
 	x_top = ceil (x_top);
 	y_top = ceil (y_top);
-	ld_canvas_translate_document_coordinates (data->self, &x_top, &y_top);
+	ld_canvas_translate_diagram_coordinates (data->self, &x_top, &y_top);
 
 	/* Iterate over all the points. */
 	for     (x = x_top; x <= data->exposed_rect.x + data->exposed_rect.width;
@@ -592,11 +592,11 @@ draw_grid (GtkWidget *widget, DrawData *data)
 }
 
 static void
-draw_document (GtkWidget *widget, DrawData *data)
+draw_diagram (GtkWidget *widget, DrawData *data)
 {
 	GSList *objects;
 
-	if (!data->self->priv->document)
+	if (!data->self->priv->diagram)
 		return;
 
 	cairo_save (data->cr);
@@ -604,25 +604,25 @@ draw_document (GtkWidget *widget, DrawData *data)
 	cairo_set_source_rgb (data->cr, 0, 0, 0);
 	cairo_set_line_width (data->cr, 1 / data->scale);
 
-	/* Draw objects from the document. */
-	objects = ld_document_get_objects (data->self->priv->document);
-	g_slist_foreach (objects, (GFunc) draw_document_cb, data);
+	/* Draw objects from the diagram. */
+	objects = ld_diagram_get_objects (data->self->priv->diagram);
+	g_slist_foreach (objects, (GFunc) draw_diagram_cb, data);
 
 	cairo_restore (data->cr);
 }
 
 static void
-draw_document_cb (gpointer link_data, DrawData *data)
+draw_diagram_cb (gpointer link_data, DrawData *data)
 {
 	g_return_if_fail (link_data != NULL);
 	g_return_if_fail (data != NULL);
 
-	if (LD_IS_DOCUMENT_SYMBOL (link_data))
-		draw_symbol (LD_DOCUMENT_SYMBOL (link_data), data);
+	if (LD_IS_DIAGRAM_SYMBOL (link_data))
+		draw_symbol (LD_DIAGRAM_SYMBOL (link_data), data);
 }
 
 static void
-draw_symbol (LdDocumentSymbol *document_symbol, DrawData *data)
+draw_symbol (LdDiagramSymbol *diagram_symbol, DrawData *data)
 {
 	LdSymbol *symbol;
 	LdSymbolArea area;
@@ -631,19 +631,19 @@ draw_symbol (LdDocumentSymbol *document_symbol, DrawData *data)
 	if (!data->self->priv->library)
 		return;
 	symbol = ld_library_find_symbol (data->self->priv->library,
-		ld_document_symbol_get_class (document_symbol));
+		ld_diagram_symbol_get_class (diagram_symbol));
 
 	/* TODO: Resolve this better; draw a cross or whatever. */
 	if (!symbol)
 	{
 		g_warning ("Cannot find symbol %s in the library.",
-			ld_document_symbol_get_class (document_symbol));
+			ld_diagram_symbol_get_class (diagram_symbol));
 		return;
 	}
 
-	x = ld_document_object_get_x (LD_DOCUMENT_OBJECT (document_symbol));
-	y = ld_document_object_get_y (LD_DOCUMENT_OBJECT (document_symbol));
-	ld_canvas_translate_document_coordinates (data->self, &x, &y);
+	x = ld_diagram_object_get_x (LD_DIAGRAM_OBJECT (diagram_symbol));
+	y = ld_diagram_object_get_y (LD_DIAGRAM_OBJECT (diagram_symbol));
+	ld_canvas_translate_diagram_coordinates (data->self, &x, &y);
 
 	/* TODO: Rotate the space for other orientations. */
 	cairo_save (data->cr);
diff --git a/src/ld-canvas.h b/src/ld-canvas.h
index 037e727..6f2c1db 100644
--- a/src/ld-canvas.h
+++ b/src/ld-canvas.h
@@ -65,14 +65,14 @@ GType ld_canvas_get_type (void) G_GNUC_CONST;
 
 LdCanvas *ld_canvas_new (void);
 
-void ld_canvas_set_document (LdCanvas *self, LdDocument *document);
-LdDocument *ld_canvas_get_document (LdCanvas *self);
+void ld_canvas_set_diagram (LdCanvas *self, LdDiagram *diagram);
+LdDiagram *ld_canvas_get_diagram (LdCanvas *self);
 void ld_canvas_set_library (LdCanvas *self, LdLibrary *library);
 LdLibrary *ld_canvas_get_library (LdCanvas *self);
 
 void ld_canvas_translate_canvas_coordinates (LdCanvas *self,
 	gdouble *x, gdouble *y);
-void ld_canvas_translate_document_coordinates (LdCanvas *self,
+void ld_canvas_translate_diagram_coordinates (LdCanvas *self,
 	gdouble *x, gdouble *y);
 
 /* TODO: The rest of the interface. */
diff --git a/src/ld-diagram-object.c b/src/ld-diagram-object.c
new file mode 100644
index 0000000..fea70c0
--- /dev/null
+++ b/src/ld-diagram-object.c
@@ -0,0 +1,189 @@
+/*
+ * ld-diagram-object.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include <gtk/gtk.h>
+
+#include "config.h"
+
+#include "ld-diagram-object.h"
+
+
+/**
+ * SECTION:ld-diagram-object
+ * @short_description: A diagram object.
+ * @see_also: #LdDiagram, #LdCanvas
+ *
+ * #LdDiagramObject represents an object in an #LdDiagram.
+ */
+
+/*
+ * LdDiagramObjectPrivate:
+ * @x: The X coordinate of this object.
+ * @y: The Y coordinate of this object.
+ */
+struct _LdDiagramObjectPrivate
+{
+	gdouble x;
+	gdouble y;
+};
+
+G_DEFINE_ABSTRACT_TYPE (LdDiagramObject, ld_diagram_object, G_TYPE_OBJECT);
+
+enum
+{
+	PROP_0,
+	PROP_X,
+	PROP_Y
+};
+
+static void ld_diagram_object_get_property (GObject *object, guint property_id,
+	GValue *value, GParamSpec *pspec);
+static void ld_diagram_object_set_property (GObject *object, guint property_id,
+	const GValue *value, GParamSpec *pspec);
+
+
+static void
+ld_diagram_object_class_init (LdDiagramObjectClass *klass)
+{
+	GObjectClass *object_class;
+	GParamSpec *pspec;
+
+	object_class = G_OBJECT_CLASS (klass);
+	object_class->get_property = ld_diagram_object_get_property;
+	object_class->set_property = ld_diagram_object_set_property;
+
+/**
+ * LdDiagramObject:x:
+ *
+ * The X coordinate of the object.
+ */
+	pspec = g_param_spec_double ("x", "X",
+		"The X coordinate of this object.",
+		-G_MAXDOUBLE, G_MAXDOUBLE, 0, G_PARAM_READWRITE);
+	g_object_class_install_property (object_class, PROP_X, pspec);
+
+/**
+ * LdDiagramObject:y:
+ *
+ * The Y coordinate of the object.
+ */
+	pspec = g_param_spec_double ("y", "Y",
+		"The Y coordinate of this object.",
+		-G_MAXDOUBLE, G_MAXDOUBLE, 0, G_PARAM_READWRITE);
+	g_object_class_install_property (object_class, PROP_Y, pspec);
+
+	g_type_class_add_private (klass, sizeof (LdDiagramObjectPrivate));
+}
+
+static void
+ld_diagram_object_init (LdDiagramObject *self)
+{
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+		(self, LD_TYPE_DIAGRAM_OBJECT, LdDiagramObjectPrivate);
+}
+
+static void
+ld_diagram_object_get_property (GObject *object, guint property_id,
+	GValue *value, GParamSpec *pspec)
+{
+	LdDiagramObject *self;
+
+	self = LD_DIAGRAM_OBJECT (object);
+	switch (property_id)
+	{
+	case PROP_X:
+		g_value_set_double (value, ld_diagram_object_get_x (self));
+		break;
+	case PROP_Y:
+		g_value_set_double (value, ld_diagram_object_get_y (self));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+	}
+}
+
+static void
+ld_diagram_object_set_property (GObject *object, guint property_id,
+	const GValue *value, GParamSpec *pspec)
+{
+	LdDiagramObject *self;
+
+	self = LD_DIAGRAM_OBJECT (object);
+	switch (property_id)
+	{
+	case PROP_X:
+		ld_diagram_object_set_x (self, g_value_get_double (value));
+		break;
+	case PROP_Y:
+		ld_diagram_object_set_y (self, g_value_get_double (value));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+	}
+}
+
+
+/**
+ * ld_diagram_object_get_x:
+ * @self: An #LdDiagramObject object.
+ *
+ * Return value: The X coordinate of the object.
+ */
+gdouble
+ld_diagram_object_get_x (LdDiagramObject *self)
+{
+	g_return_val_if_fail (LD_IS_DIAGRAM_OBJECT (self), 0);
+	return self->priv->x;
+}
+
+/**
+ * ld_diagram_object_get_y:
+ * @self: An #LdDiagramObject object.
+ *
+ * Return value: The Y coordinate of the object.
+ */
+gdouble
+ld_diagram_object_get_y (LdDiagramObject *self)
+{
+	g_return_val_if_fail (LD_IS_DIAGRAM_OBJECT (self), 0);
+	return self->priv->y;
+}
+
+/**
+ * ld_diagram_object_set_x:
+ * @self: An #LdDiagramObject object.
+ * @x: The new X coordinate.
+ *
+ * Set the X coordinate of the object.
+ */
+void
+ld_diagram_object_set_x (LdDiagramObject *self, gdouble x)
+{
+	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (self));
+	self->priv->x = x;
+
+	g_object_notify (G_OBJECT (self), "x");
+}
+
+/**
+ * ld_diagram_object_set_y:
+ * @self: An #LdDiagramObject object.
+ * @y: The new Y coordinate.
+ *
+ * Set the Y coordinate of the object.
+ */
+void
+ld_diagram_object_set_y (LdDiagramObject *self, gdouble y)
+{
+	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (self));
+	self->priv->y = y;
+
+	g_object_notify (G_OBJECT (self), "y");
+}
diff --git a/src/ld-diagram-object.h b/src/ld-diagram-object.h
new file mode 100644
index 0000000..c727602
--- /dev/null
+++ b/src/ld-diagram-object.h
@@ -0,0 +1,65 @@
+/*
+ * ld-diagram-object.h
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#ifndef __LD_DIAGRAM_OBJECT_H__
+#define __LD_DIAGRAM_OBJECT_H__
+
+G_BEGIN_DECLS
+
+
+#define LD_TYPE_DIAGRAM_OBJECT (ld_diagram_object_get_type ())
+#define LD_DIAGRAM_OBJECT(obj) (G_TYPE_CHECK_INSTANCE_CAST \
+	((obj), LD_TYPE_DIAGRAM_OBJECT, LdDiagramObject))
+#define LD_DIAGRAM_OBJECT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
+	((klass), LD_TYPE_DIAGRAM_OBJECT, LdDiagramObjectClass))
+#define LD_IS_DIAGRAM_OBJECT(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((obj), LD_TYPE_DIAGRAM_OBJECT))
+#define LD_IS_DIAGRAM_OBJECT_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((klass), LD_TYPE_DIAGRAM_OBJECT))
+#define LD_DIAGRAM_OBJECT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
+	((obj), LD_DIAGRAM_OBJECT, LdDiagramObjectClass))
+
+typedef struct _LdDiagramObject LdDiagramObject;
+typedef struct _LdDiagramObjectPrivate LdDiagramObjectPrivate;
+typedef struct _LdDiagramObjectClass LdDiagramObjectClass;
+
+
+/**
+ * LdDiagramObject:
+ */
+struct _LdDiagramObject
+{
+/*< private >*/
+	GObject parent_instance;
+	LdDiagramObjectPrivate *priv;
+};
+
+/**
+ * LdDiagramObjectClass:
+ */
+struct _LdDiagramObjectClass
+{
+/*< private >*/
+	GObjectClass parent_class;
+};
+
+
+GType ld_diagram_object_get_type (void) G_GNUC_CONST;
+
+gdouble ld_diagram_object_get_x (LdDiagramObject *self);
+gdouble ld_diagram_object_get_y (LdDiagramObject *self);
+void ld_diagram_object_set_x (LdDiagramObject *self, gdouble x);
+void ld_diagram_object_set_y (LdDiagramObject *self, gdouble y);
+
+
+G_END_DECLS
+
+#endif /* ! __LD_DIAGRAM_OBJECT_H__ */
+
diff --git a/src/ld-diagram-symbol.c b/src/ld-diagram-symbol.c
new file mode 100644
index 0000000..aafcb67
--- /dev/null
+++ b/src/ld-diagram-symbol.c
@@ -0,0 +1,109 @@
+/*
+ * ld-diagram-symbol.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include <gtk/gtk.h>
+
+#include "config.h"
+
+#include "ld-diagram-object.h"
+#include "ld-diagram-symbol.h"
+
+
+/**
+ * SECTION:ld-diagram-symbol
+ * @short_description: A symbol object.
+ * @see_also: #LdDiagramObject
+ *
+ * #LdDiagramSymbol is an implementation of #LdDiagramObject.
+ */
+
+/*
+ * LdDiagramSymbolPrivate:
+ * @klass: The class of this symbol.
+ */
+struct _LdDiagramSymbolPrivate
+{
+	gchar *klass;
+};
+
+G_DEFINE_TYPE (LdDiagramSymbol, ld_diagram_symbol, LD_TYPE_DIAGRAM_OBJECT);
+
+static void ld_diagram_symbol_finalize (GObject *gobject);
+
+
+static void
+ld_diagram_symbol_class_init (LdDiagramSymbolClass *klass)
+{
+	GObjectClass *object_class;
+
+	object_class = G_OBJECT_CLASS (klass);
+	object_class->finalize = ld_diagram_symbol_finalize;
+
+	/* TODO: A property for the class. */
+
+	g_type_class_add_private (klass, sizeof (LdDiagramSymbolPrivate));
+}
+
+static void
+ld_diagram_symbol_init (LdDiagramSymbol *self)
+{
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+		(self, LD_TYPE_DIAGRAM_SYMBOL, LdDiagramSymbolPrivate);
+}
+
+static void
+ld_diagram_symbol_finalize (GObject *gobject)
+{
+	LdDiagramSymbol *self;
+
+	self = LD_DIAGRAM_SYMBOL (gobject);
+
+	if (self->priv->klass)
+		g_free (self->priv->klass);
+
+	/* Chain up to the parent class. */
+	G_OBJECT_CLASS (ld_diagram_symbol_parent_class)->finalize (gobject);
+}
+
+
+/**
+ * ld_diagram_symbol_new:
+ * @klass: The class of the symbol (symbol identifier).
+ *
+ * Return value: A new #LdDiagramSymbol object.
+ */
+LdDiagramSymbol *
+ld_diagram_symbol_new (const gchar *klass)
+{
+	LdDiagramSymbol *self;
+
+	self = g_object_new (LD_TYPE_DIAGRAM_SYMBOL, NULL);
+	ld_diagram_symbol_set_class (self, klass);
+	return self;
+}
+
+
+/* TODO: gtk-doc comments. */
+const gchar *
+ld_diagram_symbol_get_class (LdDiagramSymbol *self)
+{
+	g_return_val_if_fail (LD_IS_DIAGRAM_SYMBOL (self), NULL);
+	return self->priv->klass;
+}
+
+void
+ld_diagram_symbol_set_class (LdDiagramSymbol *self, const gchar *klass)
+{
+	g_return_if_fail (LD_IS_DIAGRAM_SYMBOL (self));
+
+	if (self->priv->klass)
+		g_free (self->priv->klass);
+	self->priv->klass = g_strdup (klass);
+}
diff --git a/src/ld-diagram-symbol.h b/src/ld-diagram-symbol.h
new file mode 100644
index 0000000..09d8739
--- /dev/null
+++ b/src/ld-diagram-symbol.h
@@ -0,0 +1,64 @@
+/*
+ * ld-diagram-symbol.h
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#ifndef __LD_DIAGRAM_SYMBOL_H__
+#define __LD_DIAGRAM_SYMBOL_H__
+
+G_BEGIN_DECLS
+
+
+#define LD_TYPE_DIAGRAM_SYMBOL (ld_diagram_symbol_get_type ())
+#define LD_DIAGRAM_SYMBOL(obj) (G_TYPE_CHECK_INSTANCE_CAST \
+	((obj), LD_TYPE_DIAGRAM_SYMBOL, LdDiagramSymbol))
+#define LD_DIAGRAM_SYMBOL_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
+	((klass), LD_TYPE_DIAGRAM_SYMBOL, LdDiagramSymbolClass))
+#define LD_IS_DIAGRAM_SYMBOL(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((obj), LD_TYPE_DIAGRAM_SYMBOL))
+#define LD_IS_DIAGRAM_SYMBOL_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((klass), LD_TYPE_DIAGRAM_SYMBOL))
+#define LD_DIAGRAM_SYMBOL_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
+	((obj), LD_DIAGRAM_SYMBOL, LdDiagramSymbolClass))
+
+typedef struct _LdDiagramSymbol LdDiagramSymbol;
+typedef struct _LdDiagramSymbolPrivate LdDiagramSymbolPrivate;
+typedef struct _LdDiagramSymbolClass LdDiagramSymbolClass;
+
+
+/**
+ * LdDiagramSymbol:
+ */
+struct _LdDiagramSymbol
+{
+/*< private >*/
+	LdDiagramObject parent_instance;
+	LdDiagramSymbolPrivate *priv;
+};
+
+/**
+ * LdDiagramSymbolClass:
+ */
+struct _LdDiagramSymbolClass
+{
+/*< private >*/
+	LdDiagramObjectClass parent_class;
+};
+
+
+GType ld_diagram_symbol_get_type (void) G_GNUC_CONST;
+
+LdDiagramSymbol *ld_diagram_symbol_new (const gchar *klass);
+const gchar *ld_diagram_symbol_get_class (LdDiagramSymbol *self);
+void ld_diagram_symbol_set_class (LdDiagramSymbol *self, const gchar *klass);
+
+
+G_END_DECLS
+
+#endif /* ! __LD_DIAGRAM_SYMBOL_H__ */
+
diff --git a/src/ld-diagram.c b/src/ld-diagram.c
new file mode 100644
index 0000000..e19a6d5
--- /dev/null
+++ b/src/ld-diagram.c
@@ -0,0 +1,455 @@
+/*
+ * ld-diagram.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include <gtk/gtk.h>
+#include <json-glib/json-glib.h>
+
+#include "config.h"
+
+#include "ld-diagram-object.h"
+#include "ld-diagram.h"
+
+
+/**
+ * SECTION:ld-diagram
+ * @short_description: A diagram object.
+ * @see_also: #LdCanvas
+ *
+ * #LdDiagram is a model for storing diagrams.
+ */
+
+/*
+ * LdDiagramPrivate:
+ * @modified: Whether the diagram has been modified.
+ * @objects: All the objects in the diagram.
+ * @selection: All currently selected objects.
+ * @connections: Connections between objects.
+ */
+struct _LdDiagramPrivate
+{
+	gboolean modified;
+
+	GSList *objects;
+	GSList *selection;
+	GSList *connections;
+};
+
+G_DEFINE_TYPE (LdDiagram, ld_diagram, G_TYPE_OBJECT);
+
+enum
+{
+	PROP_0,
+	PROP_MODIFIED
+};
+
+static void ld_diagram_get_property (GObject *object, guint property_id,
+	GValue *value, GParamSpec *pspec);
+static void ld_diagram_set_property (GObject *object, guint property_id,
+	const GValue *value, GParamSpec *pspec);
+static void ld_diagram_dispose (GObject *gobject);
+static void ld_diagram_finalize (GObject *gobject);
+
+static void ld_diagram_real_changed (LdDiagram *self);
+static void ld_diagram_clear_internal (LdDiagram *self);
+
+
+static void
+ld_diagram_class_init (LdDiagramClass *klass)
+{
+	GObjectClass *object_class;
+	GParamSpec *pspec;
+
+	object_class = G_OBJECT_CLASS (klass);
+	object_class->get_property = ld_diagram_get_property;
+	object_class->set_property = ld_diagram_set_property;
+	object_class->dispose = ld_diagram_dispose;
+	object_class->finalize = ld_diagram_finalize;
+
+	klass->changed = ld_diagram_real_changed;
+
+/**
+ * LdDiagram:modified:
+ *
+ * Whether the diagram has been modified.
+ */
+	pspec = g_param_spec_boolean ("modified", "Modified",
+		"Whether the diagram has been modified.",
+		FALSE, G_PARAM_READWRITE);
+	g_object_class_install_property (object_class, PROP_MODIFIED, pspec);
+
+/**
+ * LdDiagram::changed:
+ * @diagram: The diagram object.
+ *
+ * Contents of the diagram have changed.
+ */
+	klass->changed_signal = g_signal_new
+		("changed", G_TYPE_FROM_CLASS (klass),
+		G_SIGNAL_RUN_LAST,
+		G_STRUCT_OFFSET (LdDiagramClass, changed), NULL, NULL,
+		g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
+
+	g_type_class_add_private (klass, sizeof (LdDiagramPrivate));
+}
+
+static void
+ld_diagram_init (LdDiagram *self)
+{
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+		(self, LD_TYPE_DIAGRAM, LdDiagramPrivate);
+}
+
+static void
+ld_diagram_get_property (GObject *object, guint property_id,
+	GValue *value, GParamSpec *pspec)
+{
+	LdDiagram *self;
+
+	self = LD_DIAGRAM (object);
+	switch (property_id)
+	{
+	case PROP_MODIFIED:
+		g_value_set_boolean (value, ld_diagram_get_modified (self));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+	}
+}
+
+static void
+ld_diagram_set_property (GObject *object, guint property_id,
+	const GValue *value, GParamSpec *pspec)
+{
+	LdDiagram *self;
+
+	self = LD_DIAGRAM (object);
+	switch (property_id)
+	{
+	case PROP_MODIFIED:
+		ld_diagram_set_modified (self, g_value_get_boolean (value));
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+	}
+}
+
+static void
+ld_diagram_dispose (GObject *gobject)
+{
+	LdDiagram *self;
+
+	self = LD_DIAGRAM (gobject);
+	ld_diagram_clear_internal (self);
+
+	/* Chain up to the parent class. */
+	G_OBJECT_CLASS (ld_diagram_parent_class)->dispose (gobject);
+}
+
+static void
+ld_diagram_finalize (GObject *gobject)
+{
+	/* Chain up to the parent class. */
+	G_OBJECT_CLASS (ld_diagram_parent_class)->finalize (gobject);
+}
+
+static void
+ld_diagram_real_changed (LdDiagram *self)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+
+	ld_diagram_set_modified (self, TRUE);
+}
+
+
+/**
+ * ld_diagram_new:
+ *
+ * Create an instance.
+ */
+LdDiagram *
+ld_diagram_new (void)
+{
+	return g_object_new (LD_TYPE_DIAGRAM, NULL);
+}
+
+/**
+ * ld_diagram_clear:
+ * @self: An #LdDiagram object.
+ *
+ * Clear the whole diagram with it's objects and selection.
+ */
+void
+ld_diagram_clear (LdDiagram *self)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+
+	ld_diagram_clear_internal (self);
+
+	g_signal_emit (self,
+		LD_DIAGRAM_GET_CLASS (self)->changed_signal, 0);
+}
+
+/*
+ * ld_diagram_clear_internal:
+ * @self: An #LdDiagram object.
+ *
+ * Do the same what ld_diagram_clear() does but don't emit signals.
+ */
+static void
+ld_diagram_clear_internal (LdDiagram *self)
+{
+	g_slist_free (self->priv->connections);
+	self->priv->connections = NULL;
+
+	g_slist_foreach (self->priv->selection, (GFunc) g_object_unref, NULL);
+	g_slist_free (self->priv->selection);
+	self->priv->selection = NULL;
+
+	g_slist_foreach (self->priv->objects, (GFunc) g_object_unref, NULL);
+	g_slist_free (self->priv->objects);
+	self->priv->objects = NULL;
+}
+
+/**
+ * ld_diagram_load_from_file:
+ * @self: An #LdDiagram object.
+ * @filename: A filename.
+ * @error: Return location for a GError, or NULL.
+ *
+ * Load a file into the diagram.
+ *
+ * Return value: TRUE if the file could be loaded, FALSE otherwise.
+ */
+gboolean
+ld_diagram_load_from_file (LdDiagram *self,
+	const gchar *filename, GError **error)
+{
+	JsonParser *parser;
+	GError *json_error;
+
+	g_return_val_if_fail (LD_IS_DIAGRAM (self), FALSE);
+	g_return_val_if_fail (filename != NULL, FALSE);
+
+	/* TODO: Implement loading for real. This is just a stub. */
+	parser = json_parser_new ();
+
+	json_error = NULL;
+	json_parser_load_from_file (parser, filename, &json_error);
+	if (json_error)
+	{
+		g_propagate_error (error, json_error);
+		g_object_unref (parser);
+		return FALSE;
+	}
+
+	ld_diagram_clear (self);
+	g_object_unref (parser);
+	return TRUE;
+}
+
+/**
+ * ld_diagram_save_to_file:
+ * @self: An #LdDiagram object.
+ * @filename: A filename.
+ * @error: Return location for a GError, or NULL.
+ *
+ * Save the diagram into a file.
+ *
+ * Return value: TRUE if the diagram could be saved, FALSE otherwise.
+ */
+gboolean
+ld_diagram_save_to_file (LdDiagram *self,
+	const gchar *filename, GError **error)
+{
+	JsonGenerator *generator;
+	JsonNode *root;
+	GError *json_error;
+
+	g_return_val_if_fail (LD_IS_DIAGRAM (self), FALSE);
+	g_return_val_if_fail (filename != NULL, FALSE);
+
+	/* TODO: Implement saving for real. This is just a stub. */
+	generator = json_generator_new ();
+	g_object_set (generator, "pretty", TRUE, NULL);
+
+	/* XXX: json-glib dislikes empty objects. */
+	root = json_node_new (JSON_NODE_OBJECT);
+	json_generator_set_root (generator, root);
+	json_node_free (root);
+
+	json_error = NULL;
+	json_generator_to_file (generator, filename, &json_error);
+	if (json_error)
+	{
+		g_propagate_error (error, json_error);
+		g_object_unref (generator);
+		return FALSE;
+	}
+	g_object_unref (generator);
+	return TRUE;
+}
+
+/**
+ * ld_diagram_get_modified:
+ * @self: An #LdDiagram object.
+ *
+ * Return value: The modification status of diagram.
+ */
+gboolean
+ld_diagram_get_modified (LdDiagram *self)
+{
+	g_return_val_if_fail (LD_IS_DIAGRAM (self), FALSE);
+	return self->priv->modified;
+}
+
+/**
+ * ld_diagram_set_modified:
+ * @self: An #LdDiagram object.
+ * @value: Whether the diagram has been modified.
+ *
+ * Set the modification status of diagram.
+ */
+void
+ld_diagram_set_modified (LdDiagram *self, gboolean value)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+	self->priv->modified = value;
+
+	g_object_notify (G_OBJECT (self), "modified");
+}
+
+/**
+ * ld_diagram_get_objects:
+ * @self: An #LdDiagram object.
+ *
+ * Get a list of objects in the diagram.
+ * You mustn't make any changes to the list.
+ */
+GSList *
+ld_diagram_get_objects (LdDiagram *self)
+{
+	g_return_val_if_fail (LD_IS_DIAGRAM (self), NULL);
+	return self->priv->objects;
+}
+
+/**
+ * ld_diagram_insert_object:
+ * @self: An #LdDiagram object.
+ * @object: The object to be inserted.
+ * @pos: The position at which the object is to be inserted.
+ *       Negative values will append to the end.
+ *
+ * Insert an object into the diagram.
+ */
+void
+ld_diagram_insert_object (LdDiagram *self, LdDiagramObject *object, gint pos)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (object));
+
+	if (!g_slist_find (self->priv->objects, object))
+	{
+		self->priv->objects =
+			g_slist_insert (self->priv->objects, object, pos);
+		g_object_ref (object);
+
+		g_signal_emit (self,
+			LD_DIAGRAM_GET_CLASS (self)->changed_signal, 0);
+	}
+}
+
+/**
+ * ld_diagram_remove_object:
+ * @self: An #LdDiagram object.
+ * @object: The object to be removed.
+ *
+ * Remove an object from the diagram.
+ */
+void
+ld_diagram_remove_object (LdDiagram *self, LdDiagramObject *object)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (object));
+
+	if (g_slist_find (self->priv->objects, object))
+	{
+		ld_diagram_selection_remove (self, object);
+
+		self->priv->objects = g_slist_remove (self->priv->objects, object);
+		g_object_unref (object);
+
+		g_signal_emit (self,
+			LD_DIAGRAM_GET_CLASS (self)->changed_signal, 0);
+	}
+}
+
+/**
+ * ld_diagram_get_selection:
+ * @self: An #LdDiagram object.
+ *
+ * Get a list of objects that are currently selected in the diagram.
+ * You mustn't make any changes to the list.
+ */
+GSList *
+ld_diagram_get_selection (LdDiagram *self)
+{
+	g_return_val_if_fail (LD_IS_DIAGRAM (self), NULL);
+	return self->priv->selection;
+}
+
+/**
+ * ld_diagram_selection_add:
+ * @self: An #LdDiagram object.
+ * @object: The object to be added to the selection.
+ * @pos: The position at which the object is to be inserted.
+ *       Negative values will append to the end.
+ *
+ * Add an object to selection.
+ */
+void
+ld_diagram_selection_add (LdDiagram *self, LdDiagramObject *object, gint pos)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (object));
+
+	if (!g_slist_find (self->priv->selection, object)
+		&& g_slist_find (self->priv->objects, object))
+	{
+		self->priv->selection =
+			g_slist_insert (self->priv->selection, object, pos);
+		g_object_ref (object);
+
+		g_signal_emit (self,
+			LD_DIAGRAM_GET_CLASS (self)->changed_signal, 0);
+	}
+}
+
+/**
+ * ld_diagram_selection_remove:
+ * @self: An #LdDiagram object.
+ * @object: The object to be removed from the selection.
+ *
+ * Remove an object from the selection.
+ */
+void
+ld_diagram_selection_remove (LdDiagram *self, LdDiagramObject *object)
+{
+	g_return_if_fail (LD_IS_DIAGRAM (self));
+	g_return_if_fail (LD_IS_DIAGRAM_OBJECT (object));
+
+	if (g_slist_find (self->priv->selection, object))
+	{
+		self->priv->selection = g_slist_remove (self->priv->selection, object);
+		g_object_unref (object);
+
+		g_signal_emit (self,
+			LD_DIAGRAM_GET_CLASS (self)->changed_signal, 0);
+	}
+}
diff --git a/src/ld-diagram.h b/src/ld-diagram.h
new file mode 100644
index 0000000..ce3b39e
--- /dev/null
+++ b/src/ld-diagram.h
@@ -0,0 +1,94 @@
+/*
+ * ld-diagram.h
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2010. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#ifndef __LD_DIAGRAM_H__
+#define __LD_DIAGRAM_H__
+
+G_BEGIN_DECLS
+
+
+#define LD_TYPE_DIAGRAM (ld_diagram_get_type ())
+#define LD_DIAGRAM(obj) (G_TYPE_CHECK_INSTANCE_CAST \
+	((obj), LD_TYPE_DIAGRAM, LdDiagram))
+#define LD_DIAGRAM_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
+	((klass), LD_TYPE_DIAGRAM, LdDiagramClass))
+#define LD_IS_DIAGRAM(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((obj), LD_TYPE_DIAGRAM))
+#define LD_IS_DIAGRAM_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((klass), LD_TYPE_DIAGRAM))
+#define LD_DIAGRAM_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
+	((obj), LD_DIAGRAM, LdDiagramClass))
+
+typedef struct _LdDiagram LdDiagram;
+typedef struct _LdDiagramClass LdDiagramClass;
+typedef struct _LdDiagramPrivate LdDiagramPrivate;
+
+
+/**
+ * LdDiagram:
+ *
+ * A diagram object.
+ */
+struct _LdDiagram
+{
+/*< private >*/
+	GObject parent_instance;
+	LdDiagramPrivate *priv;
+};
+
+struct _LdDiagramClass
+{
+/*< private >*/
+	GObjectClass parent_class;
+
+	/* FIXME: Add a selection_changed signal? */
+	guint changed_signal;
+
+	void (*changed) (LdDiagram *self);
+};
+
+
+GType ld_diagram_get_type (void) G_GNUC_CONST;
+
+LdDiagram *ld_diagram_new (void);
+void ld_diagram_clear (LdDiagram *self);
+gboolean ld_diagram_load_from_file (LdDiagram *self,
+	const gchar *filename, GError **error);
+gboolean ld_diagram_save_to_file (LdDiagram *self,
+	const gchar *filename, GError **error);
+
+gboolean ld_diagram_get_modified (LdDiagram *self);
+void ld_diagram_set_modified (LdDiagram *self, gboolean value);
+
+GSList *ld_diagram_get_objects (LdDiagram *self);
+void ld_diagram_insert_object (LdDiagram *self,
+	LdDiagramObject *object, gint pos);
+void ld_diagram_remove_object (LdDiagram *self,
+	LdDiagramObject *object);
+
+GSList *ld_diagram_get_selection (LdDiagram *self);
+void ld_diagram_selection_add (LdDiagram *self,
+	LdDiagramObject *object, gint pos);
+void ld_diagram_selection_remove (LdDiagram *self,
+	LdDiagramObject *object);
+
+/*
+GSList *ld_diagram_get_connections (LdDiagram *self);
+void ld_diagram_connection_add (LdDiagram *self,
+	LdConnection *connection, gint pos);
+void ld_diagram_connection_remove (LdDiagram *self,
+	LdConnection *connection);
+*/
+
+
+G_END_DECLS
+
+#endif /* ! __LD_DIAGRAM_H__ */
+
diff --git a/src/ld-document-object.c b/src/ld-document-object.c
deleted file mode 100644
index 09aa3cc..0000000
--- a/src/ld-document-object.c
+++ /dev/null
@@ -1,189 +0,0 @@
-/*
- * ld-document-object.c
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#include <gtk/gtk.h>
-
-#include "config.h"
-
-#include "ld-document-object.h"
-
-
-/**
- * SECTION:ld-document-object
- * @short_description: A document object.
- * @see_also: #LdDocument, #LdCanvas
- *
- * #LdDocumentObject represents an object in an #LdDocument.
- */
-
-/*
- * LdDocumentObjectPrivate:
- * @x: The X coordinate of this object.
- * @y: The Y coordinate of this object.
- */
-struct _LdDocumentObjectPrivate
-{
-	gdouble x;
-	gdouble y;
-};
-
-G_DEFINE_ABSTRACT_TYPE (LdDocumentObject, ld_document_object, G_TYPE_OBJECT);
-
-enum
-{
-	PROP_0,
-	PROP_X,
-	PROP_Y
-};
-
-static void ld_document_object_get_property (GObject *object, guint property_id,
-	GValue *value, GParamSpec *pspec);
-static void ld_document_object_set_property (GObject *object, guint property_id,
-	const GValue *value, GParamSpec *pspec);
-
-
-static void
-ld_document_object_class_init (LdDocumentObjectClass *klass)
-{
-	GObjectClass *object_class;
-	GParamSpec *pspec;
-
-	object_class = G_OBJECT_CLASS (klass);
-	object_class->get_property = ld_document_object_get_property;
-	object_class->set_property = ld_document_object_set_property;
-
-/**
- * LdDocumentObject:x:
- *
- * The X coordinate of the object.
- */
-	pspec = g_param_spec_double ("x", "X",
-		"The X coordinate of this object.",
-		-G_MAXDOUBLE, G_MAXDOUBLE, 0, G_PARAM_READWRITE);
-	g_object_class_install_property (object_class, PROP_X, pspec);
-
-/**
- * LdDocumentObject:y:
- *
- * The Y coordinate of the object.
- */
-	pspec = g_param_spec_double ("y", "Y",
-		"The Y coordinate of this object.",
-		-G_MAXDOUBLE, G_MAXDOUBLE, 0, G_PARAM_READWRITE);
-	g_object_class_install_property (object_class, PROP_Y, pspec);
-
-	g_type_class_add_private (klass, sizeof (LdDocumentObjectPrivate));
-}
-
-static void
-ld_document_object_init (LdDocumentObject *self)
-{
-	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
-		(self, LD_TYPE_DOCUMENT_OBJECT, LdDocumentObjectPrivate);
-}
-
-static void
-ld_document_object_get_property (GObject *object, guint property_id,
-	GValue *value, GParamSpec *pspec)
-{
-	LdDocumentObject *self;
-
-	self = LD_DOCUMENT_OBJECT (object);
-	switch (property_id)
-	{
-	case PROP_X:
-		g_value_set_double (value, ld_document_object_get_x (self));
-		break;
-	case PROP_Y:
-		g_value_set_double (value, ld_document_object_get_y (self));
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-	}
-}
-
-static void
-ld_document_object_set_property (GObject *object, guint property_id,
-	const GValue *value, GParamSpec *pspec)
-{
-	LdDocumentObject *self;
-
-	self = LD_DOCUMENT_OBJECT (object);
-	switch (property_id)
-	{
-	case PROP_X:
-		ld_document_object_set_x (self, g_value_get_double (value));
-		break;
-	case PROP_Y:
-		ld_document_object_set_y (self, g_value_get_double (value));
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-	}
-}
-
-
-/**
- * ld_document_object_get_x:
- * @self: An #LdDocumentObject object.
- *
- * Return value: The X coordinate of the object.
- */
-gdouble
-ld_document_object_get_x (LdDocumentObject *self)
-{
-	g_return_val_if_fail (LD_IS_DOCUMENT_OBJECT (self), 0);
-	return self->priv->x;
-}
-
-/**
- * ld_document_object_get_y:
- * @self: An #LdDocumentObject object.
- *
- * Return value: The Y coordinate of the object.
- */
-gdouble
-ld_document_object_get_y (LdDocumentObject *self)
-{
-	g_return_val_if_fail (LD_IS_DOCUMENT_OBJECT (self), 0);
-	return self->priv->y;
-}
-
-/**
- * ld_document_object_set_x:
- * @self: An #LdDocumentObject object.
- * @x: The new X coordinate.
- *
- * Set the X coordinate of the object.
- */
-void
-ld_document_object_set_x (LdDocumentObject *self, gdouble x)
-{
-	g_return_if_fail (LD_IS_DOCUMENT_OBJECT (self));
-	self->priv->x = x;
-
-	g_object_notify (G_OBJECT (self), "x");
-}
-
-/**
- * ld_document_object_set_y:
- * @self: An #LdDocumentObject object.
- * @y: The new Y coordinate.
- *
- * Set the Y coordinate of the object.
- */
-void
-ld_document_object_set_y (LdDocumentObject *self, gdouble y)
-{
-	g_return_if_fail (LD_IS_DOCUMENT_OBJECT (self));
-	self->priv->y = y;
-
-	g_object_notify (G_OBJECT (self), "y");
-}
diff --git a/src/ld-document-object.h b/src/ld-document-object.h
deleted file mode 100644
index 0333878..0000000
--- a/src/ld-document-object.h
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * ld-document-object.h
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#ifndef __LD_DOCUMENT_OBJECT_H__
-#define __LD_DOCUMENT_OBJECT_H__
-
-G_BEGIN_DECLS
-
-
-#define LD_TYPE_DOCUMENT_OBJECT (ld_document_object_get_type ())
-#define LD_DOCUMENT_OBJECT(obj) (G_TYPE_CHECK_INSTANCE_CAST \
-	((obj), LD_TYPE_DOCUMENT_OBJECT, LdDocumentObject))
-#define LD_DOCUMENT_OBJECT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
-	((klass), LD_TYPE_DOCUMENT_OBJECT, LdDocumentObjectClass))
-#define LD_IS_DOCUMENT_OBJECT(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
-	((obj), LD_TYPE_DOCUMENT_OBJECT))
-#define LD_IS_DOCUMENT_OBJECT_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
-	((klass), LD_TYPE_DOCUMENT_OBJECT))
-#define LD_DOCUMENT_OBJECT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
-	((obj), LD_DOCUMENT_OBJECT, LdDocumentObjectClass))
-
-typedef struct _LdDocumentObject LdDocumentObject;
-typedef struct _LdDocumentObjectPrivate LdDocumentObjectPrivate;
-typedef struct _LdDocumentObjectClass LdDocumentObjectClass;
-
-
-/**
- * LdDocumentObject:
- */
-struct _LdDocumentObject
-{
-/*< private >*/
-	GObject parent_instance;
-	LdDocumentObjectPrivate *priv;
-};
-
-/**
- * LdDocumentObjectClass:
- */
-struct _LdDocumentObjectClass
-{
-/*< private >*/
-	GObjectClass parent_class;
-};
-
-
-GType ld_document_object_get_type (void) G_GNUC_CONST;
-
-gdouble ld_document_object_get_x (LdDocumentObject *self);
-gdouble ld_document_object_get_y (LdDocumentObject *self);
-void ld_document_object_set_x (LdDocumentObject *self, gdouble x);
-void ld_document_object_set_y (LdDocumentObject *self, gdouble y);
-
-
-G_END_DECLS
-
-#endif /* ! __LD_DOCUMENT_OBJECT_H__ */
-
diff --git a/src/ld-document-symbol.c b/src/ld-document-symbol.c
deleted file mode 100644
index b415d54..0000000
--- a/src/ld-document-symbol.c
+++ /dev/null
@@ -1,108 +0,0 @@
-/*
- * ld-document-symbol.c
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#include <gtk/gtk.h>
-
-#include "config.h"
-
-#include "ld-document-object.h"
-#include "ld-document-symbol.h"
-
-
-/**
- * SECTION:ld-document-symbol
- * @short_description: A symbol object.
- * @see_also: #LdDocumentObject
- *
- * #LdDocumentSymbol is an implementation of #LdDocumentObject.
- */
-
-/*
- * LdDocumentSymbolPrivate:
- * @klass: The class of this symbol.
- */
-struct _LdDocumentSymbolPrivate
-{
-	gchar *klass;
-};
-
-G_DEFINE_TYPE (LdDocumentSymbol, ld_document_symbol, LD_TYPE_DOCUMENT_OBJECT);
-
-static void ld_document_symbol_finalize (GObject *gobject);
-
-
-static void
-ld_document_symbol_class_init (LdDocumentSymbolClass *klass)
-{
-	GObjectClass *object_class;
-
-	object_class = G_OBJECT_CLASS (klass);
-	object_class->finalize = ld_document_symbol_finalize;
-
-	/* TODO: A property for the class. */
-
-	g_type_class_add_private (klass, sizeof (LdDocumentSymbolPrivate));
-}
-
-static void
-ld_document_symbol_init (LdDocumentSymbol *self)
-{
-	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
-		(self, LD_TYPE_DOCUMENT_SYMBOL, LdDocumentSymbolPrivate);
-}
-
-static void
-ld_document_symbol_finalize (GObject *gobject)
-{
-	LdDocumentSymbol *self;
-
-	self = LD_DOCUMENT_SYMBOL (gobject);
-
-	if (self->priv->klass)
-		g_free (self->priv->klass);
-
-	/* Chain up to the parent class. */
-	G_OBJECT_CLASS (ld_document_symbol_parent_class)->finalize (gobject);
-}
-
-
-/**
- * ld_document_symbol_new:
- * @klass: The class of the symbol (symbol identifier).
- *
- * Return value: A new #LdDocumentSymbol object.
- */
-LdDocumentSymbol *
-ld_document_symbol_new (const gchar *klass)
-{
-	LdDocumentSymbol *self;
-
-	self = g_object_new (LD_TYPE_DOCUMENT_SYMBOL, NULL);
-	ld_document_symbol_set_class (self, klass);
-	return self;
-}
-
-
-const gchar *
-ld_document_symbol_get_class (LdDocumentSymbol *self)
-{
-	g_return_val_if_fail (LD_IS_DOCUMENT_SYMBOL (self), NULL);
-	return self->priv->klass;
-}
-
-void
-ld_document_symbol_set_class (LdDocumentSymbol *self, const gchar *klass)
-{
-	g_return_if_fail (LD_IS_DOCUMENT_SYMBOL (self));
-
-	if (self->priv->klass)
-		g_free (self->priv->klass);
-	self->priv->klass = g_strdup (klass);
-}
diff --git a/src/ld-document-symbol.h b/src/ld-document-symbol.h
deleted file mode 100644
index 87e132c..0000000
--- a/src/ld-document-symbol.h
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * ld-document-symbol.h
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#ifndef __LD_DOCUMENT_SYMBOL_H__
-#define __LD_DOCUMENT_SYMBOL_H__
-
-G_BEGIN_DECLS
-
-
-#define LD_TYPE_DOCUMENT_SYMBOL (ld_document_symbol_get_type ())
-#define LD_DOCUMENT_SYMBOL(obj) (G_TYPE_CHECK_INSTANCE_CAST \
-	((obj), LD_TYPE_DOCUMENT_SYMBOL, LdDocumentSymbol))
-#define LD_DOCUMENT_SYMBOL_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
-	((klass), LD_TYPE_DOCUMENT_SYMBOL, LdDocumentSymbolClass))
-#define LD_IS_DOCUMENT_SYMBOL(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
-	((obj), LD_TYPE_DOCUMENT_SYMBOL))
-#define LD_IS_DOCUMENT_SYMBOL_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
-	((klass), LD_TYPE_DOCUMENT_SYMBOL))
-#define LD_DOCUMENT_SYMBOL_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
-	((obj), LD_DOCUMENT_SYMBOL, LdDocumentSymbolClass))
-
-typedef struct _LdDocumentSymbol LdDocumentSymbol;
-typedef struct _LdDocumentSymbolPrivate LdDocumentSymbolPrivate;
-typedef struct _LdDocumentSymbolClass LdDocumentSymbolClass;
-
-
-/**
- * LdDocumentSymbol:
- */
-struct _LdDocumentSymbol
-{
-/*< private >*/
-	LdDocumentObject parent_instance;
-	LdDocumentSymbolPrivate *priv;
-};
-
-/**
- * LdDocumentSymbolClass:
- */
-struct _LdDocumentSymbolClass
-{
-/*< private >*/
-	LdDocumentObjectClass parent_class;
-};
-
-
-GType ld_document_symbol_get_type (void) G_GNUC_CONST;
-
-LdDocumentSymbol *ld_document_symbol_new (const gchar *klass);
-const gchar *ld_document_symbol_get_class (LdDocumentSymbol *self);
-void ld_document_symbol_set_class (LdDocumentSymbol *self, const gchar *klass);
-
-
-G_END_DECLS
-
-#endif /* ! __LD_DOCUMENT_SYMBOL_H__ */
-
diff --git a/src/ld-document.c b/src/ld-document.c
deleted file mode 100644
index 79beebf..0000000
--- a/src/ld-document.c
+++ /dev/null
@@ -1,455 +0,0 @@
-/*
- * ld-document.c
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#include <gtk/gtk.h>
-#include <json-glib/json-glib.h>
-
-#include "config.h"
-
-#include "ld-document-object.h"
-#include "ld-document.h"
-
-
-/**
- * SECTION:ld-document
- * @short_description: A document object.
- * @see_also: #LdCanvas
- *
- * #LdDocument is a model for storing documents.
- */
-
-/*
- * LdDocumentPrivate:
- * @modified: Whether the document has been modified.
- * @objects: All the objects in the document.
- * @selection: All currently selected objects.
- * @connections: Connections between objects.
- */
-struct _LdDocumentPrivate
-{
-	gboolean modified;
-
-	GSList *objects;
-	GSList *selection;
-	GSList *connections;
-};
-
-G_DEFINE_TYPE (LdDocument, ld_document, G_TYPE_OBJECT);
-
-enum
-{
-	PROP_0,
-	PROP_MODIFIED
-};
-
-static void ld_document_get_property (GObject *object, guint property_id,
-	GValue *value, GParamSpec *pspec);
-static void ld_document_set_property (GObject *object, guint property_id,
-	const GValue *value, GParamSpec *pspec);
-static void ld_document_dispose (GObject *gobject);
-static void ld_document_finalize (GObject *gobject);
-
-static void ld_document_real_changed (LdDocument *self);
-static void ld_document_clear_internal (LdDocument *self);
-
-
-static void
-ld_document_class_init (LdDocumentClass *klass)
-{
-	GObjectClass *object_class;
-	GParamSpec *pspec;
-
-	object_class = G_OBJECT_CLASS (klass);
-	object_class->get_property = ld_document_get_property;
-	object_class->set_property = ld_document_set_property;
-	object_class->dispose = ld_document_dispose;
-	object_class->finalize = ld_document_finalize;
-
-	klass->changed = ld_document_real_changed;
-
-/**
- * LdDocument:modified:
- *
- * Whether the document has been modified.
- */
-	pspec = g_param_spec_boolean ("modified", "Modified",
-		"Whether the document has been modified.",
-		FALSE, G_PARAM_READWRITE);
-	g_object_class_install_property (object_class, PROP_MODIFIED, pspec);
-
-/**
- * LdDocument::changed:
- * @document: The document object.
- *
- * Contents of the document have changed.
- */
-	klass->changed_signal = g_signal_new
-		("changed", G_TYPE_FROM_CLASS (klass),
-		G_SIGNAL_RUN_LAST,
-		G_STRUCT_OFFSET (LdDocumentClass, changed), NULL, NULL,
-		g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
-
-	g_type_class_add_private (klass, sizeof (LdDocumentPrivate));
-}
-
-static void
-ld_document_init (LdDocument *self)
-{
-	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
-		(self, LD_TYPE_DOCUMENT, LdDocumentPrivate);
-}
-
-static void
-ld_document_get_property (GObject *object, guint property_id,
-	GValue *value, GParamSpec *pspec)
-{
-	LdDocument *self;
-
-	self = LD_DOCUMENT (object);
-	switch (property_id)
-	{
-	case PROP_MODIFIED:
-		g_value_set_boolean (value, ld_document_get_modified (self));
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-	}
-}
-
-static void
-ld_document_set_property (GObject *object, guint property_id,
-	const GValue *value, GParamSpec *pspec)
-{
-	LdDocument *self;
-
-	self = LD_DOCUMENT (object);
-	switch (property_id)
-	{
-	case PROP_MODIFIED:
-		ld_document_set_modified (self, g_value_get_boolean (value));
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-	}
-}
-
-static void
-ld_document_dispose (GObject *gobject)
-{
-	LdDocument *self;
-
-	self = LD_DOCUMENT (gobject);
-	ld_document_clear_internal (self);
-
-	/* Chain up to the parent class. */
-	G_OBJECT_CLASS (ld_document_parent_class)->dispose (gobject);
-}
-
-static void
-ld_document_finalize (GObject *gobject)
-{
-	/* Chain up to the parent class. */
-	G_OBJECT_CLASS (ld_document_parent_class)->finalize (gobject);
-}
-
-static void
-ld_document_real_changed (LdDocument *self)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-
-	ld_document_set_modified (self, TRUE);
-}
-
-
-/**
- * ld_document_new:
- *
- * Create an instance.
- */
-LdDocument *
-ld_document_new (void)
-{
-	return g_object_new (LD_TYPE_DOCUMENT, NULL);
-}
-
-/**
- * ld_document_clear:
- * @self: An #LdDocument object.
- *
- * Clear the whole document with it's objects and selection.
- */
-void
-ld_document_clear (LdDocument *self)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-
-	ld_document_clear_internal (self);
-
-	g_signal_emit (self,
-		LD_DOCUMENT_GET_CLASS (self)->changed_signal, 0);
-}
-
-/*
- * ld_document_clear_internal:
- * @self: An #LdDocument object.
- *
- * Do the same what ld_document_clear() does but don't emit signals.
- */
-static void
-ld_document_clear_internal (LdDocument *self)
-{
-	g_slist_free (self->priv->connections);
-	self->priv->connections = NULL;
-
-	g_slist_foreach (self->priv->selection, (GFunc) g_object_unref, NULL);
-	g_slist_free (self->priv->selection);
-	self->priv->selection = NULL;
-
-	g_slist_foreach (self->priv->objects, (GFunc) g_object_unref, NULL);
-	g_slist_free (self->priv->objects);
-	self->priv->objects = NULL;
-}
-
-/**
- * ld_document_load_from_file:
- * @self: An #LdDocument object.
- * @filename: A filename.
- * @error: Return location for a GError, or NULL.
- *
- * Load a file into the document.
- *
- * Return value: TRUE if the file could be loaded, FALSE otherwise.
- */
-gboolean
-ld_document_load_from_file (LdDocument *self,
-	const gchar *filename, GError **error)
-{
-	JsonParser *parser;
-	GError *json_error;
-
-	g_return_val_if_fail (LD_IS_DOCUMENT (self), FALSE);
-	g_return_val_if_fail (filename != NULL, FALSE);
-
-	/* TODO: Implement loading for real. This is just a stub. */
-	parser = json_parser_new ();
-
-	json_error = NULL;
-	json_parser_load_from_file (parser, filename, &json_error);
-	if (json_error)
-	{
-		g_propagate_error (error, json_error);
-		g_object_unref (parser);
-		return FALSE;
-	}
-
-	ld_document_clear (self);
-	g_object_unref (parser);
-	return TRUE;
-}
-
-/**
- * ld_document_save_to_file:
- * @self: An #LdDocument object.
- * @filename: A filename.
- * @error: Return location for a GError, or NULL.
- *
- * Save the document into a file.
- *
- * Return value: TRUE if the document could be saved, FALSE otherwise.
- */
-gboolean
-ld_document_save_to_file (LdDocument *self,
-	const gchar *filename, GError **error)
-{
-	JsonGenerator *generator;
-	JsonNode *root;
-	GError *json_error;
-
-	g_return_val_if_fail (LD_IS_DOCUMENT (self), FALSE);
-	g_return_val_if_fail (filename != NULL, FALSE);
-
-	/* TODO: Implement saving for real. This is just a stub. */
-	generator = json_generator_new ();
-	g_object_set (generator, "pretty", TRUE, NULL);
-
-	/* XXX: json-glib dislikes empty objects. */
-	root = json_node_new (JSON_NODE_OBJECT);
-	json_generator_set_root (generator, root);
-	json_node_free (root);
-
-	json_error = NULL;
-	json_generator_to_file (generator, filename, &json_error);
-	if (json_error)
-	{
-		g_propagate_error (error, json_error);
-		g_object_unref (generator);
-		return FALSE;
-	}
-	g_object_unref (generator);
-	return TRUE;
-}
-
-/**
- * ld_document_get_modified:
- * @self: An #LdDocument object.
- *
- * Return value: The modification status of document.
- */
-gboolean
-ld_document_get_modified (LdDocument *self)
-{
-	g_return_val_if_fail (LD_IS_DOCUMENT (self), FALSE);
-	return self->priv->modified;
-}
-
-/**
- * ld_document_set_modified:
- * @self: An #LdDocument object.
- * @value: Whether the document has been modified.
- *
- * Set the modification status of document.
- */
-void
-ld_document_set_modified (LdDocument *self, gboolean value)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-	self->priv->modified = value;
-
-	g_object_notify (G_OBJECT (self), "modified");
-}
-
-/**
- * ld_document_get_objects:
- * @self: An #LdDocument object.
- *
- * Get a list of objects in the document.
- * You mustn't make any changes to the list.
- */
-GSList *
-ld_document_get_objects (LdDocument *self)
-{
-	g_return_val_if_fail (LD_IS_DOCUMENT (self), NULL);
-	return self->priv->objects;
-}
-
-/**
- * ld_document_insert_object:
- * @self: An #LdDocument object.
- * @object: The object to be inserted.
- * @pos: The position at which the object is to be inserted.
- *       Negative values will append to the end.
- *
- * Insert an object into the document.
- */
-void
-ld_document_insert_object (LdDocument *self, LdDocumentObject *object, gint pos)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-	g_return_if_fail (LD_IS_DOCUMENT_OBJECT (object));
-
-	if (!g_slist_find (self->priv->objects, object))
-	{
-		self->priv->objects =
-			g_slist_insert (self->priv->objects, object, pos);
-		g_object_ref (object);
-
-		g_signal_emit (self,
-			LD_DOCUMENT_GET_CLASS (self)->changed_signal, 0);
-	}
-}
-
-/**
- * ld_document_remove_object:
- * @self: An #LdDocument object.
- * @object: The object to be removed.
- *
- * Remove an object from the document.
- */
-void
-ld_document_remove_object (LdDocument *self, LdDocumentObject *object)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-	g_return_if_fail (LD_IS_DOCUMENT_OBJECT (object));
-
-	if (g_slist_find (self->priv->objects, object))
-	{
-		ld_document_selection_remove (self, object);
-
-		self->priv->objects = g_slist_remove (self->priv->objects, object);
-		g_object_unref (object);
-
-		g_signal_emit (self,
-			LD_DOCUMENT_GET_CLASS (self)->changed_signal, 0);
-	}
-}
-
-/**
- * ld_document_get_selection:
- * @self: An #LdDocument object.
- *
- * Get a list of objects that are currently selected in the document.
- * You mustn't make any changes to the list.
- */
-GSList *
-ld_document_get_selection (LdDocument *self)
-{
-	g_return_val_if_fail (LD_IS_DOCUMENT (self), NULL);
-	return self->priv->selection;
-}
-
-/**
- * ld_document_selection_add:
- * @self: An #LdDocument object.
- * @object: The object to be added to the selection.
- * @pos: The position at which the object is to be inserted.
- *       Negative values will append to the end.
- *
- * Add an object to selection.
- */
-void
-ld_document_selection_add (LdDocument *self, LdDocumentObject *object, gint pos)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-	g_return_if_fail (LD_IS_DOCUMENT_OBJECT (object));
-
-	if (!g_slist_find (self->priv->selection, object)
-		&& g_slist_find (self->priv->objects, object))
-	{
-		self->priv->selection =
-			g_slist_insert (self->priv->selection, object, pos);
-		g_object_ref (object);
-
-		g_signal_emit (self,
-			LD_DOCUMENT_GET_CLASS (self)->changed_signal, 0);
-	}
-}
-
-/**
- * ld_document_selection_remove:
- * @self: An #LdDocument object.
- * @object: The object to be removed from the selection.
- *
- * Remove an object from the selection.
- */
-void
-ld_document_selection_remove (LdDocument *self, LdDocumentObject *object)
-{
-	g_return_if_fail (LD_IS_DOCUMENT (self));
-	g_return_if_fail (LD_IS_DOCUMENT_OBJECT (object));
-
-	if (g_slist_find (self->priv->selection, object))
-	{
-		self->priv->selection = g_slist_remove (self->priv->selection, object);
-		g_object_unref (object);
-
-		g_signal_emit (self,
-			LD_DOCUMENT_GET_CLASS (self)->changed_signal, 0);
-	}
-}
diff --git a/src/ld-document.h b/src/ld-document.h
deleted file mode 100644
index 13602aa..0000000
--- a/src/ld-document.h
+++ /dev/null
@@ -1,94 +0,0 @@
-/*
- * ld-document.h
- *
- * This file is a part of logdiag.
- * Copyright Přemysl Janouch 2010. All rights reserved.
- *
- * See the file LICENSE for licensing information.
- *
- */
-
-#ifndef __LD_DOCUMENT_H__
-#define __LD_DOCUMENT_H__
-
-G_BEGIN_DECLS
-
-
-#define LD_TYPE_DOCUMENT (ld_document_get_type ())
-#define LD_DOCUMENT(obj) (G_TYPE_CHECK_INSTANCE_CAST \
-	((obj), LD_TYPE_DOCUMENT, LdDocument))
-#define LD_DOCUMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
-	((klass), LD_TYPE_DOCUMENT, LdDocumentClass))
-#define LD_IS_DOCUMENT(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
-	((obj), LD_TYPE_DOCUMENT))
-#define LD_IS_DOCUMENT_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
-	((klass), LD_TYPE_DOCUMENT))
-#define LD_DOCUMENT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
-	((obj), LD_DOCUMENT, LdDocumentClass))
-
-typedef struct _LdDocument LdDocument;
-typedef struct _LdDocumentClass LdDocumentClass;
-typedef struct _LdDocumentPrivate LdDocumentPrivate;
-
-
-/**
- * LdDocument:
- *
- * A document object.
- */
-struct _LdDocument
-{
-/*< private >*/
-	GObject parent_instance;
-	LdDocumentPrivate *priv;
-};
-
-struct _LdDocumentClass
-{
-/*< private >*/
-	GObjectClass parent_class;
-
-	/* FIXME: Add a selection_changed signal? */
-	guint changed_signal;
-
-	void (*changed) (LdDocument *self);
-};
-
-
-GType ld_document_get_type (void) G_GNUC_CONST;
-
-LdDocument *ld_document_new (void);
-void ld_document_clear (LdDocument *self);
-gboolean ld_document_load_from_file (LdDocument *self,
-	const gchar *filename, GError **error);
-gboolean ld_document_save_to_file (LdDocument *self,
-	const gchar *filename, GError **error);
-
-gboolean ld_document_get_modified (LdDocument *self);
-void ld_document_set_modified (LdDocument *self, gboolean value);
-
-GSList *ld_document_get_objects (LdDocument *self);
-void ld_document_insert_object (LdDocument *self,
-	LdDocumentObject *object, gint pos);
-void ld_document_remove_object (LdDocument *self,
-	LdDocumentObject *object);
-
-GSList *ld_document_get_selection (LdDocument *self);
-void ld_document_selection_add (LdDocument *self,
-	LdDocumentObject *object, gint pos);
-void ld_document_selection_remove (LdDocument *self,
-	LdDocumentObject *object);
-
-/*
-GSList *ld_document_get_connections (LdDocument *self);
-void ld_document_connection_add (LdDocument *self,
-	LdConnection *connection, gint pos);
-void ld_document_connection_remove (LdDocument *self,
-	LdConnection *connection);
-*/
-
-
-G_END_DECLS
-
-#endif /* ! __LD_DOCUMENT_H__ */
-
diff --git a/src/ld-symbol.c b/src/ld-symbol.c
index 014016e..6cffee0 100644
--- a/src/ld-symbol.c
+++ b/src/ld-symbol.c
@@ -69,9 +69,9 @@ ld_symbol_area_get_type (void)
 /**
  * SECTION:ld-symbol
  * @short_description: A symbol.
- * @see_also: #LdDocument, #LdCanvas
+ * @see_also: #LdDiagram, #LdCanvas
  *
- * #LdSymbol represents a symbol in the #LdDocument that is in turn
+ * #LdSymbol represents a symbol in the #LdDiagram that is in turn
  * drawn onto the #LdCanvas.
  *
  * All implementations of this abstract class are required to use
diff --git a/src/ld-window-main.c b/src/ld-window-main.c
index 2a72eb4..05a2284 100644
--- a/src/ld-window-main.c
+++ b/src/ld-window-main.c
@@ -18,9 +18,9 @@
 #include "ld-symbol-category.h"
 #include "ld-library.h"
 
-#include "ld-document-object.h"
-#include "ld-document-symbol.h"
-#include "ld-document.h"
+#include "ld-diagram-object.h"
+#include "ld-diagram-symbol.h"
+#include "ld-diagram.h"
 
 #include "ld-canvas.h"
 
@@ -86,7 +86,7 @@ struct _LdWindowMainPrivate
 
 	LdLibrary *library;
 
-	LdDocument *document;
+	LdDiagram *diagram;
 	gchar *filename;
 
 	GtkWidget *canvas_window;
@@ -328,16 +328,16 @@ ld_window_main_init (LdWindowMain *self)
 		priv->symbol_menu.button_release_handler);
 
 	/* Initialize the backend. */
-	priv->document = ld_document_new ();
+	priv->diagram = ld_diagram_new ();
 
-	g_signal_connect_data (priv->document, "changed",
+	g_signal_connect_data (priv->diagram, "changed",
 		G_CALLBACK (update_title), self,
 		NULL, G_CONNECT_AFTER | G_CONNECT_SWAPPED);
 
 	priv->library = ld_library_new ();
 	ld_library_load (priv->library, PROJECT_SHARE_DIR "library");
 
-	ld_canvas_set_document (priv->canvas, priv->document);
+	ld_canvas_set_diagram (priv->canvas, priv->diagram);
 	ld_canvas_set_library (priv->canvas, priv->library);
 
 	load_library_toolbar (self);
@@ -367,7 +367,7 @@ ld_window_main_finalize (GObject *gobject)
 	 * and gtk_object_destroy () should be used for it.
 	 */
 	g_object_unref (self->priv->library);
-	g_object_unref (self->priv->document);
+	g_object_unref (self->priv->diagram);
 	g_object_unref (self->priv->ui_manager);
 	g_object_unref (self->priv->action_group);
 
@@ -404,7 +404,7 @@ update_title (LdWindowMain *self)
 
 	name = diagram_get_name (self);
 	title = g_strdup_printf ("%s%s - %s",
-		ld_document_get_modified (self->priv->document) ? "*" : "",
+		ld_diagram_get_modified (self->priv->diagram) ? "*" : "",
 		name, PROJECT_NAME);
 	gtk_window_set_title (GTK_WINDOW (self), title);
 
@@ -808,7 +808,7 @@ diagram_get_name (LdWindowMain *self)
  * diagram_set_filename:
  * @filename: The new filename. May be NULL for a new, yet unsaved, file.
  *
- * Set the filename corresponding to the currently opened document.
+ * Set the filename corresponding to the currently opened diagram.
  * The function takes ownership of the string.
  */
 static void
@@ -838,8 +838,8 @@ diagram_new (LdWindowMain *self)
 		return;
 
 	/* TODO: Reset canvas view to the center. */
-	ld_document_clear (self->priv->document);
-	ld_document_set_modified (self->priv->document, FALSE);
+	ld_diagram_clear (self->priv->diagram);
+	ld_diagram_set_modified (self->priv->diagram, FALSE);
 
 	diagram_set_filename (self, NULL);
 }
@@ -863,7 +863,7 @@ diagram_save (LdWindowMain *self)
 	}
 
 	error = NULL;
-	ld_document_save_to_file (self->priv->document,
+	ld_diagram_save_to_file (self->priv->diagram,
 		self->priv->filename, &error);
 	if (error)
 	{
@@ -883,7 +883,7 @@ diagram_save (LdWindowMain *self)
 	}
 	else
 	{
-		ld_document_set_modified (self->priv->document, FALSE);
+		ld_diagram_set_modified (self->priv->diagram, FALSE);
 		update_title (self);
 	}
 }
@@ -936,7 +936,7 @@ diagram_show_open_dialog (LdWindowMain *self)
 		filename = gtk_file_chooser_get_filename (GTK_FILE_CHOOSER (dialog));
 
 		error = NULL;
-		ld_document_load_from_file (self->priv->document, filename, &error);
+		ld_diagram_load_from_file (self->priv->diagram, filename, &error);
 		if (error)
 		{
 			GtkWidget *message_dialog;
@@ -955,7 +955,7 @@ diagram_show_open_dialog (LdWindowMain *self)
 		}
 		else
 		{
-			ld_document_set_modified (self->priv->document, FALSE);
+			ld_diagram_set_modified (self->priv->diagram, FALSE);
 			diagram_set_filename (self, filename);
 		}
 	}
@@ -1014,7 +1014,7 @@ may_close_diagram (LdWindowMain *self, const gchar *dialog_message)
 	g_return_val_if_fail (LD_IS_WINDOW_MAIN (self), TRUE);
 	g_return_val_if_fail (dialog_message != NULL, TRUE);
 
-	if (!ld_document_get_modified (self->priv->document))
+	if (!ld_diagram_get_modified (self->priv->diagram))
 		return TRUE;
 
 	name = diagram_get_name (self);