Implement more of LdCanvas.

1. Add methods for coordinate translation between cairo/GtkWidget
   coordinates and LdDocument coordinates.
2. Draw the grid correctly (also make it significantly faster).
3. Place the canvas into a GtkScrolledWindow and register
   the set_scroll_adjustments signal in the GtkWidget base class.
4. Allow scrolling inside of an area of 200 x 200 units (for now).
   In the future, it should be possible to go to infinity.

1 files changed, 15 insertions, 4 deletions

diff --git a/src/ld-canvas.h b/src/ld-canvas.h
index a31b2b7..037e727 100644
--- a/src/ld-canvas.h
+++ b/src/ld-canvas.h
@@ -48,22 +48,33 @@ struct _LdCanvasClass
 /*< private >*/
 	GtkDrawingAreaClass parent_class;
 
-/*
-	void (*set_scroll_adjustments) (GtkAdjustment *x, GtkAdjustment *y);
-*/
+	void (*set_scroll_adjustments) (LdCanvas *self,
+		GtkAdjustment *horizontal, GtkAdjustment *vertical);
 };
 
 
+/**
+ * LD_CANVAS_BASE_UNIT:
+ *
+ * The length of the base unit in milimetres.
+ */
+#define LD_CANVAS_BASE_UNIT_LENGTH 2.5
+
+
 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_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,
+	gdouble *x, gdouble *y);
+
 /* TODO: The rest of the interface. */