--- a/src/animate.c	Sat Aug 09 21:34:07 2008 +0800
+++ b/src/animate.c	Sat Aug 09 22:16:23 2008 +0800
@@ -358,6 +358,98 @@
     return (mb_action_t *)shift;
 }
 
+
+#include "paint.h"
+typedef struct _mb_chgcolor mb_chgcolor_t;
+
+struct _mb_chgcolor {
+    mb_action_t action;
+
+    co_comp_t r, g, b, a;
+    paint_t *paint;
+
+    mb_timeval_t start_time;
+    const mb_timeval_t *playing_time;
+    co_comp_t s_r, s_g, s_b, s_a; /*!< saved RGBA values. */
+};
+
+static void mb_chgcolor_start(mb_action_t *act,
+			      const mb_timeval_t *now,
+			      const mb_timeval_t *playing_time,
+			      redraw_man_t *rdman) {
+    mb_chgcolor_t *chg = (mb_chgcolor_t *)act;
+
+    MB_TIMEVAL_CP(&chg->start_time, now);
+    chg->playing_time = playing_time; /* playing_time is in word,
+				       * it live time is as long as
+				       * actions. */
+    paint_color_get(chg->paint,
+		    &chg->s_r, &chg->s_g,
+		    &chg->s_b, &chg->s_a);
+}
+
+static void mb_chgcolor_step(mb_action_t *act,
+			     const mb_timeval_t *now,
+			     redraw_man_t *rdman) {
+    mb_chgcolor_t *chg = (mb_chgcolor_t *)act;
+    mb_timeval_t diff;
+    co_comp_t r, g, b, a;
+    float ratio, comp;
+
+    MB_TIMEVAL_CP(&diff, now);
+    MB_TIMEVAL_DIFF(&diff, &chg->start_time);
+    ratio = comp_mb_timeval_ratio(&diff, chg->playing_time);
+    comp = 1 - ratio;
+
+    r = chg->s_r * comp + ratio * chg->r;
+    g = chg->s_g * comp + ratio * chg->g;
+    b = chg->s_b * comp + ratio * chg->b;
+    a = chg->s_a * comp + ratio * chg->a;
+    paint_color_set(chg->paint, r, g, b, a);
+
+    rdman_paint_changed(rdman, chg->paint);
+}
+
+static void mb_chgcolor_stop(mb_action_t *act,
+			     const mb_timeval_t *now,
+			     redraw_man_t *rdman) {
+    mb_chgcolor_t *chg = (mb_chgcolor_t *)act;
+
+    paint_color_set(chg->paint, chg->r, chg->g, chg->b, chg->a);
+
+    rdman_paint_changed(rdman, chg->paint);
+}
+
+static void mb_chgcolor_free(mb_action_t *act) {
+    free(act);
+}
+
+mb_action_t *mb_chgcolor_new(co_comp_t r, co_comp_t g,
+			     co_comp_t b, co_comp_t a,
+			     paint_t *paint, mb_word_t *word) {
+    mb_chgcolor_t *chg;
+
+    chg = (mb_chgcolor_t *)malloc(sizeof(mb_chgcolor_t));
+    if(chg == NULL)
+	return NULL;
+
+    chg->r = r;
+    chg->g = g;
+    chg->b = b;
+    chg->a = a;
+
+    chg->paint = paint;
+
+    chg->action.start = mb_chgcolor_start;
+    chg->action.step = mb_chgcolor_step;
+    chg->action.stop = mb_chgcolor_stop;
+    chg->action.free = mb_chgcolor_free;
+
+    mb_word_add_action(word, (mb_action_t *)chg);
+
+    return (mb_action_t *)chg;
+}
+
 #ifdef UNITTEST
 
 #include <CUnit/Basic.h>