Implement zooming in LdWindowMain.

Add convenience methods to LdCanvas.

liblogdiag/ld-canvas.c

@@ -33,8 +33,8 @@
 #define ZOOM_MIN 0.01
 #define ZOOM_MAX 100
 #define ZOOM_DEFAULT 1
-/* Multiplication factor for zooming with mouse wheel. */
+/* Multiplication factor for zooming. */
-#define ZOOM_WHEEL_STEP 1.4
+#define ZOOM_STEP 1.4
 
 /* When drawing is requested, extend all sides of
  * the rectangle to be drawn by this number of pixels.
@@ -862,6 +862,58 @@ ld_canvas_set_zoom (LdCanvas *self, gdouble zoom)
 	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);
+}
+
 
 /* ===== Operations ======================================================== */
 
@@ -1288,10 +1340,10 @@ on_scroll (GtkWidget *widget, GdkEventScroll *event, gpointer user_data)
 	switch (event->direction)
 	{
 	case GDK_SCROLL_UP:
-		ld_canvas_set_zoom (self, self->priv->zoom * ZOOM_WHEEL_STEP);
+		ld_canvas_zoom_in (self);
 		break;
 	case GDK_SCROLL_DOWN:
-		ld_canvas_set_zoom (self, self->priv->zoom / ZOOM_WHEEL_STEP);
+		ld_canvas_zoom_out (self);
 		break;
 	default:
 		return FALSE;

liblogdiag/ld-canvas.h

@@ -80,6 +80,10 @@ void ld_canvas_diagram_to_widget_coords (LdCanvas *self,
 
 gdouble ld_canvas_get_zoom (LdCanvas *self);
 void ld_canvas_set_zoom (LdCanvas *self, gdouble zoom);
+gboolean ld_canvas_can_zoom_in (LdCanvas *self);
+void ld_canvas_zoom_in (LdCanvas *self);
+gboolean ld_canvas_can_zoom_out (LdCanvas *self);
+void ld_canvas_zoom_out (LdCanvas *self);
 
 void ld_canvas_add_object_begin (LdCanvas *self, LdDiagramObject *object);
 

src/ld-window-main.c

@@ -59,6 +59,9 @@ static void update_title (LdWindowMain *self);
 static void action_set_sensitive (LdWindowMain *self, const gchar *name,
 	gboolean sensitive);
 
+static void on_canvas_zoom_changed (LdCanvas *canvas,
+	GParamSpec *pspec, LdWindowMain *self);
+
 static void on_diagram_changed (LdDiagram *diagram, LdWindowMain *self);
 static void on_diagram_history_changed (LdDiagram *diagram,
 	GParamSpec *pspec, LdWindowMain *self);
@@ -97,6 +100,10 @@ static void on_action_redo (GtkAction *action, LdWindowMain *self);
 static void on_action_delete (GtkAction *action, LdWindowMain *self);
 static void on_action_select_all (GtkAction *action, LdWindowMain *self);
 
+static void on_action_zoom_in (GtkAction *action, LdWindowMain *self);
+static void on_action_zoom_out (GtkAction *action, LdWindowMain *self);
+static void on_action_normal_size (GtkAction *action, LdWindowMain *self);
+
 
 /* ===== Local variables =================================================== */
 
@@ -147,13 +154,13 @@ static GtkActionEntry wm_action_entries[] =
 	{"ViewMenu", NULL, Q_("_View"), NULL, NULL, NULL},
 		{"ZoomIn", GTK_STOCK_ZOOM_IN, Q_("_Zoom In"), "<Ctrl>plus",
 			Q_("Zoom into the diagram"),
-			NULL},
+			G_CALLBACK (on_action_zoom_in)},
 		{"ZoomOut", GTK_STOCK_ZOOM_OUT, Q_("Zoom _Out"), "<Ctrl>minus",
 			Q_("Zoom out of the diagram"),
-			NULL},
+			G_CALLBACK (on_action_zoom_out)},
 		{"NormalSize", GTK_STOCK_ZOOM_100, Q_("_Normal Size"), "<Ctrl>0",
 			Q_("Reset zoom level back to the default"),
-			NULL},
+			G_CALLBACK (on_action_normal_size)},
 
 	{"HelpMenu", NULL, Q_("_Help"), NULL, NULL, NULL},
 		{"About", GTK_STOCK_ABOUT, Q_("_About"), NULL,
@@ -285,6 +292,9 @@ ld_window_main_init (LdWindowMain *self)
 	ld_canvas_set_diagram (priv->canvas, priv->diagram);
 	ld_canvas_set_library (priv->canvas, priv->library);
 
+	g_signal_connect (priv->canvas, "notify::zoom",
+		G_CALLBACK (on_canvas_zoom_changed), self);
+
 	ld_library_toolbar_set_library (LD_LIBRARY_TOOLBAR (priv->library_toolbar),
 		priv->library);
 	ld_library_toolbar_set_canvas (LD_LIBRARY_TOOLBAR (priv->library_toolbar),
@@ -302,8 +312,6 @@ ld_window_main_init (LdWindowMain *self)
 	action_set_sensitive (self, "Undo", FALSE);
 	action_set_sensitive (self, "Redo", FALSE);
 	action_set_sensitive (self, "Delete", FALSE);
-	action_set_sensitive (self, "ZoomIn", FALSE);
-	action_set_sensitive (self, "ZoomOut", FALSE);
 	action_set_sensitive (self, "NormalSize", FALSE);
 
 	gtk_widget_grab_focus (GTK_WIDGET (priv->canvas));
@@ -515,10 +523,12 @@ diagram_new (LdWindowMain *self)
 		" closing it and creating a new one?"))
 		return;
 
-	/* TODO: Reset canvas view to the center. */
 	ld_diagram_clear (self->priv->diagram);
 	ld_diagram_set_modified (self->priv->diagram, FALSE);
 
+	/* TODO: Reset canvas view to the center. */
+	ld_canvas_set_zoom (self->priv->canvas, 1);
+
 	diagram_set_filename (self, NULL);
 }
 
@@ -784,6 +794,17 @@ on_symbol_chosen (LdLibraryToolbar *toolbar, LdSymbol *symbol,
 		LD_DIAGRAM_OBJECT (diagram_symbol));
 }
 
+static void
+on_canvas_zoom_changed (LdCanvas *canvas, GParamSpec *pspec, LdWindowMain *self)
+{
+	action_set_sensitive (self, "ZoomIn",
+		ld_canvas_can_zoom_in (self->priv->canvas));
+	action_set_sensitive (self, "ZoomOut",
+		ld_canvas_can_zoom_out (self->priv->canvas));
+	action_set_sensitive (self, "NormalSize",
+		ld_canvas_get_zoom (self->priv->canvas) != 1);
+}
+
 static void
 on_action_new (GtkAction *action, LdWindowMain *self)
 {
@@ -848,3 +869,21 @@ on_action_select_all (GtkAction *action, LdWindowMain *self)
 {
 	ld_diagram_select_all (self->priv->diagram);
 }
+
+static void
+on_action_zoom_in (GtkAction *action, LdWindowMain *self)
+{
+	ld_canvas_zoom_in (self->priv->canvas);
+}
+
+static void
+on_action_zoom_out (GtkAction *action, LdWindowMain *self)
+{
+	ld_canvas_zoom_out (self->priv->canvas);
+}
+
+static void
+on_action_normal_size (GtkAction *action, LdWindowMain *self)
+{
+	ld_canvas_set_zoom (self->priv->canvas, 1);
+}