--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dox/arch.h	Fri Sep 12 23:43:11 2008 +0800
@@ -0,0 +1,37 @@
+/*! \page archi Internal Architecture
+ *
+ * \image html core.png
+ * Above graphic is relationship among major objects of MadButterfly.
+ * \ref redraw_man_t, redraw manager, is supposed to manage graphic elements,
+ * shapes, and decide when and who to redraw on the output screen.
+ *
+ * \ref shape_t is base-type for all graphic objects.  It can be a path,
+ * a text, a ellipse, ..., or an image.  When the states or attributes of
+ * an graphic
+ * object changed, managing redraw_man_t, the one that manages the graphic
+ * object, will be notified.  The redraw_man_t will schedule a redrawing
+ * for every
+ * dirty objects, changed ones, and relative objects.  The relative objects
+ * are objects effected by changed ones.  For example, part of a relative
+ * object may be hidden before changing, but it is re-explored after chaning.
+ * The explored part of the object must be redrawed.
+ *
+ * The shape of shape objects are variable from type to type.  To simplize
+ * the problem, we use a rectangle to model the area occupied by an object.
+ * \ref geo_t is the one used to model the rectangle.  Shape objects should
+ * update associated \ref geo_t objects to reflect changing of them-self.
+ *
+ * \ref coord_t is used to model transformation in coordinate system.
+ * A \ref coord_t is actually an transform matrix with additional
+ * informations.  \ref coord_t
+ * objects are organized as a tree according hierachy of group tags in
+ * a SVG file.
+ *
+ * Colors or patterns used to stroke or fill shapes are described
+ * by \ref paint_t .  Every shape object has a paint, but a paint object
+ * can be used by multiple shape objects.  Once a paint is changed, all
+ * objects that associate with the paint are dirty.  They will be scheduled
+ * by associated \ref redraw_man_t object to update graphics on
+ * output screen.
+ *
+ */