--- a/src/X_main.c	Sun Aug 10 20:25:14 2008 +0800
+++ b/src/X_main.c	Sun Aug 10 21:32:42 2008 +0800
@@ -205,6 +205,7 @@
 
     tman = mb_tman_new();
     if(tman) {
+	/* Prepare an animation program. */
 	progm = mb_progm_new(10, &rdman);
 	
 	MB_TIMEVAL_SET(&start, 0, 0);
@@ -232,6 +233,7 @@
 	act = mb_chgcolor_new(1, 0, 0, 0.5, fill2, word);
 	act = mb_visibility_new(VIS_VISIBLE, coord3, word);
 	
+	/* Start playing the program. */
 	gettimeofday(&tv, NULL);
 	MB_TIMEVAL_SET(&mbtv, tv.tv_sec, tv.tv_usec);
 	mb_progm_start(progm, tman, &mbtv);

--- a/src/mb_types.h	Sun Aug 10 20:25:14 2008 +0800
+++ b/src/mb_types.h	Sun Aug 10 21:32:42 2008 +0800
@@ -11,6 +11,14 @@
 typedef struct _shnode shnode_t;
 typedef struct _paint paint_t;
 
+/*! \brief Base of paint types.
+ *
+ * Paints should be freed by users by calling paint_t::free() of
+ * the paint.
+ *
+ * \todo move member functions to a seperate structure and setup a
+ * singleton fro each paint type.
+ */
 struct _paint {
     void (*prepare)(paint_t *paint, cairo_t *cr);
     void (*free)(paint_t *paint);

--- a/src/paint.c	Sun Aug 10 20:25:14 2008 +0800
+++ b/src/paint.c	Sun Aug 10 21:32:42 2008 +0800
@@ -135,6 +135,12 @@
     return (paint_t *)linear;
 }
 
+/*! \brief Setup color stop for a linear radient paint.
+ *
+ * stops should be managed by users of the function.  It should be
+ * available before the paint being freed or changed to another
+ * array of stops.
+ */
 grad_stop_t *paint_linear_stops(paint_t *paint,
 				int n_stops,
 				grad_stop_t *stops) {
@@ -216,6 +222,12 @@
     return (paint_t *)radial;
 }
 
+/*! \brief Setup color stop for a radial radient paint.
+ *
+ * stops should be managed by users of the function.  It should be
+ * available before the paint being freed or changed to another
+ * array of stops.
+ */
 grad_stop_t *paint_radial_stops(paint_t *paint,
 				int n_stops,
 				grad_stop_t *stops) {

--- a/src/redraw_man.c	Sun Aug 10 20:25:14 2008 +0800
+++ b/src/redraw_man.c	Sun Aug 10 21:32:42 2008 +0800
@@ -231,8 +231,8 @@
     STAILQ_INS_TAIL(rdman->all_geos, geo_t, next, geo);
     rdman->n_geos++;
 
+    /*! \todo remove order number. */
 #ifdef GEO_ORDER
-    /* TODO: remove order number. */
     geo->order = ++rdman->next_geo_order;
     if(geo->order == 0) {
 	next_order = 0;
@@ -257,7 +257,7 @@
 
 /*! \brief Remove a shape object from redraw manager.
  *
- * TODO: redraw shape objects that overlaid with removed one.
+ * \todo redraw shape objects that overlaid with removed one.
  */
 int rdman_remove_shape(redraw_man_t *rdman, shape_t *shape) {
     STAILQ_REMOVE(rdman->all_geos, geo_t, next, shape->geo);
@@ -614,7 +614,7 @@
 
 #ifndef UNITTEST
 static void clean_canvas(cairo_t *cr) {
-    /* TODO: clean to background color. */
+    /*! \todo clean to background color. */
     cairo_set_source_rgb(cr, 0, 0, 0);
     cairo_paint(cr);
 }

--- a/src/shape_path.c	Sun Aug 10 20:25:14 2008 +0800
+++ b/src/shape_path.c	Sun Aug 10 21:32:42 2008 +0800
@@ -323,7 +323,7 @@
 	case 'H':
 	case 'v':
 	case 'V':
-	    /* TODO: implement h, H, v, V comamnds for path. */
+	    /*! \todo implement h, H, v, V comamnds for path. */
 	    return ERR;
 	case 'z':
 	case 'Z':
@@ -387,7 +387,7 @@
 
 /*! \brief Transform a path from user space to device space.
  *
- * TODO: associate coord_t with shape objects and transform them
+ * \todo associate coord_t with shape objects and transform them
  *       automatically.
  */
 void sh_path_transform(shape_t *shape) {

--- a/src/shape_text.c	Sun Aug 10 20:25:14 2008 +0800
+++ b/src/shape_text.c	Sun Aug 10 21:32:42 2008 +0800
@@ -109,7 +109,7 @@
     coord_trans_pos(shape->coord, &x, &y);
     r = get_extents(text, &extents);
     if(r != OK)
-	/* TODO: announce error. change return type? */
+	/*! \todo announce error. change return type? */
 	return;
 
     text->d_x = x;