diff --git a/demos/resource.c b/demos/resource.c
index 4150df7fe..35f4b0f70 100644
--- a/demos/resource.c
+++ b/demos/resource.c
@@ -118,13 +118,13 @@
 #include "res/inc/images/unchecked.data"
 #include "res/inc/images/unmuted.data"
 #include "res/inc/images/warn.data"
-#endif/*WITH_STB_IMAGE*/
+#endif /*WITH_STB_IMAGE*/
 #ifdef WITH_STB_FONT
 #include "res/inc/fonts/default.res"
 #else
 #include "res/inc/fonts/default.data"
-#endif/*WITH_STB_FONT*/
-#endif/*WITH_FS_RES*/
+#endif /*WITH_STB_FONT*/
+#endif /*WITH_FS_RES*/
 
 ret_t resource_init(void) {
   resource_manager_t* rm = resource_manager();
diff --git a/src/base/emitter.c b/src/base/emitter.c
index dd982fa2a..b5cc51396 100644
--- a/src/base/emitter.c
+++ b/src/base/emitter.c
@@ -31,80 +31,86 @@ emitter_t* emitter_create() {
 
 emitter_t* emitter_init(emitter_t* emitter) {
   return_value_if_fail(emitter, NULL);
+
   memset(emitter, 0x00, sizeof(emitter_t));
   emitter->enable = TRUE;
-  emitter->curr_id = 1;
+  emitter->next_id = TK_INVALID_ID + 1;
 
   return emitter;
 }
 
+static ret_t emitter_remove(emitter_t* emitter, emitter_item_t* prev, emitter_item_t* iter) {
+  return_value_if_fail(emitter != NULL && iter != NULL, RET_BAD_PARAMS);
+
+  if (emitter->curr_iter == iter) {
+    emitter->remove_curr_iter = TRUE;
+    return RET_OK;
+  }
+
+  if (iter == emitter->items) {
+    emitter->items = iter->next;
+  } else {
+    prev->next = iter->next;
+  }
+
+  TKMEM_FREE(iter);
+
+  return RET_OK;
+}
+
 ret_t emitter_dispatch(emitter_t* emitter, event_t* e) {
+  ret_t ret = RET_OK;
   return_value_if_fail(emitter != NULL && e != NULL, RET_BAD_PARAMS);
 
   if (!(e->time)) {
     e->time = time_now_ms();
   }
 
+  if (e->target == NULL) {
+    e->target = emitter;
+  }
+
   if (emitter->enable && emitter->items) {
-    uint32_t i = 0;
-    uint32_t size = emitter->size;
-    emitter_item_t* items = emitter->items;
+    emitter_item_t* iter = emitter->items;
+    emitter_item_t* prev = emitter->items;
+
+    while (iter != NULL) {
+      emitter->curr_iter = iter;
 
-    emitter->stop = FALSE;
-    for (i = 0; i < size; i++) {
-      emitter_item_t* iter = items + i;
       if (iter->type == e->type) {
-        iter->handler(iter->ctx, e);
+        ret = iter->handler(iter->ctx, e);
+        if (ret == RET_STOP) {
+          return ret;
+        } else if (ret == RET_REMOVE || emitter->remove_curr_iter) {
+          emitter->curr_iter = NULL;
+          emitter->remove_curr_iter = FALSE;
+          emitter_remove(emitter, prev, iter);
+        }
       }
 
-      if (emitter->stop) {
-        break;
-      }
+      prev = iter;
+      iter = iter->next;
     }
   }
+  emitter->curr_iter = NULL;
+  emitter->remove_curr_iter = FALSE;
 
   return RET_OK;
 }
 
-static ret_t emitter_extends(emitter_t* emitter, uint32_t nr) {
-  uint32_t capacity = 0;
-  emitter_item_t* items = NULL;
-  if (emitter->items && emitter->size < emitter->capacity) {
-    return RET_OK;
-  }
-
-  if (emitter->items == NULL) {
-    emitter->items = TKMEM_ZALLOC(emitter_item_t);
-    return_value_if_fail(emitter->items != NULL, RET_FAIL);
-
-    emitter->size = 0;
-    emitter->capacity = 1;
-
-    return RET_OK;
-  }
-
-  capacity = emitter->capacity + 5;
-  items = TKMEM_REALLOC(emitter_item_t, emitter->items, capacity);
-  return_value_if_fail(items != NULL, RET_FAIL);
-
-  emitter->items = items;
-  emitter->capacity = capacity;
-
-  return RET_OK;
-}
-
-uint32_t emitter_on(emitter_t* emitter, uint16_t etype, event_func_t handler, void* ctx) {
+uint32_t emitter_on(emitter_t* emitter, uint32_t etype, event_func_t handler, void* ctx) {
   emitter_item_t* iter = NULL;
-  return_value_if_fail(emitter != NULL && handler != NULL, 0);
-  return_value_if_fail(emitter_extends(emitter, 1) == RET_OK, 0);
+  return_value_if_fail(emitter != NULL && handler != NULL, TK_INVALID_ID);
+
+  iter = TKMEM_ZALLOC(emitter_item_t);
+  return_value_if_fail(iter != NULL, TK_INVALID_ID);
 
-  iter = emitter->items + emitter->size;
   iter->type = etype;
   iter->ctx = ctx;
   iter->handler = handler;
-  iter->id = emitter->curr_id++;
-
-  emitter->size++;
+  iter->id = emitter->next_id++;
+  iter->next = emitter->items;
+  emitter->items = iter;
 
   return iter->id;
 }
@@ -113,76 +119,76 @@ emitter_item_t* emitter_find(emitter_t* emitter, uint32_t id) {
   return_value_if_fail(emitter != NULL, NULL);
 
   if (emitter->items) {
-    uint32_t i = 0;
-    uint32_t size = emitter->size;
-    emitter_item_t* items = emitter->items;
+    emitter_item_t* iter = emitter->items;
 
-    for (i = 0; i < size; i++) {
-      emitter_item_t* iter = items + i;
+    while (iter != NULL) {
       if (iter->id == id) {
         return iter;
       }
+
+      iter = iter->next;
     }
   }
 
   return NULL;
 }
 
+uint32_t emitter_size(emitter_t* emitter) {
+  uint32_t size = 0;
+  return_value_if_fail(emitter != NULL, size);
+
+  if (emitter->items) {
+    emitter_item_t* iter = emitter->items;
+
+    while (iter != NULL) {
+      size++;
+      iter = iter->next;
+    }
+  }
+
+  return size;
+}
+
 ret_t emitter_off(emitter_t* emitter, uint32_t id) {
   return_value_if_fail(emitter != NULL, RET_BAD_PARAMS);
 
   if (emitter->items) {
-    uint32_t i = 0;
-    uint32_t size = emitter->size;
-    emitter_item_t* items = emitter->items;
+    emitter_item_t* iter = emitter->items;
+    emitter_item_t* prev = emitter->items;
 
-    for (i = 0; i < size; i++) {
-      emitter_item_t* iter = items + i;
+    while (iter != NULL) {
       if (iter->id == id) {
-        for (; i < (size - 1); i++) {
-          items[i] = items[i + 1];
-        }
-        emitter->size--;
-
-        return RET_OK;
+        return emitter_remove(emitter, prev, iter);
       }
+
+      prev = iter;
+      iter = iter->next;
     }
   }
 
   return RET_FAIL;
 }
 
-ret_t emitter_off_by_func(emitter_t* emitter, uint16_t etype, event_func_t handler, void* ctx) {
+ret_t emitter_off_by_func(emitter_t* emitter, uint32_t etype, event_func_t handler, void* ctx) {
   return_value_if_fail(emitter != NULL && handler != NULL, RET_BAD_PARAMS);
 
   if (emitter->items) {
-    uint32_t i = 0;
-    uint32_t size = emitter->size;
-    emitter_item_t* items = emitter->items;
+    emitter_item_t* iter = emitter->items;
+    emitter_item_t* prev = emitter->items;
 
-    for (i = 0; i < size; i++) {
-      emitter_item_t* iter = items + i;
+    while (iter != NULL) {
       if (iter->type == etype && iter->ctx == ctx && iter->handler == handler) {
-        for (; i < (size - 1); i++) {
-          items[i] = items[i + 1];
-        }
-        emitter->size--;
-
-        return RET_OK;
+        return emitter_remove(emitter, prev, iter);
       }
+
+      prev = iter;
+      iter = iter->next;
     }
   }
 
   return RET_FAIL;
 }
 
-ret_t emitter_stop(emitter_t* emitter) {
-  return_value_if_fail(emitter != NULL, RET_BAD_PARAMS);
-  emitter->stop = TRUE;
-
-  return RET_OK;
-}
-
 ret_t emitter_enable(emitter_t* emitter) {
   return_value_if_fail(emitter != NULL, RET_BAD_PARAMS);
   emitter->enable = TRUE;
@@ -200,7 +206,15 @@ ret_t emitter_disable(emitter_t* emitter) {
 ret_t emitter_deinit(emitter_t* emitter) {
   return_value_if_fail(emitter != NULL, RET_BAD_PARAMS);
   if (emitter->items) {
-    TKMEM_FREE(emitter->items);
+    emitter_item_t* iter = emitter->items;
+    emitter_item_t* next = emitter->items;
+
+    while (iter != NULL) {
+      next = iter->next;
+      TKMEM_FREE(iter);
+      iter = next;
+    }
+    emitter->items = NULL;
   }
 
   return RET_OK;
diff --git a/src/base/emitter.h b/src/base/emitter.h
index 98602a217..d1073cf8d 100644
--- a/src/base/emitter.h
+++ b/src/base/emitter.h
@@ -26,36 +26,175 @@
 
 BEGIN_C_DECLS
 
-typedef struct _emitter_item_t {
-  uint32_t id;
-  uint16_t type;
-  void* ctx;
-  event_func_t handler;
-} emitter_item_t;
+struct _emitter_item_t;
+typedef struct _emitter_item_t emitter_item_t;
 
+struct _emitter_item_t {
+  void* ctx;
+  uint32_t id;
+  uint32_t type;
+  event_func_t handler;
+
+  emitter_item_t* next;
+};
+
+/**
+ * @class emitter_t
+ * @scriptable no
+ * 事件分发器, 用于实现观察者模式。
+ */
 typedef struct _emitter_t {
-  uint8_t size;
-  uint8_t capacity;
-  uint8_t stop;
-  uint8_t enable;
+  /**
+   * @property {emitter_item_t*} items
+   * @private
+   * 注册的回调函数集合。
+   */
   emitter_item_t* items;
-  uint32_t curr_id;
+  /**
+   * @property {uint32_t} next_id
+   * @private
+   * 下一次emitter_on返回的ID，emitter_on成功后会自动增加next_id。
+   */
+  uint32_t next_id;
+  /**
+   * @property {bool_t} enable
+   * @readonly
+   * 禁用标志。禁用时dispatch无效。
+   */
+  bool_t enable;
+  /**
+   * @property {bool_t} remove_curr_iter
+   * @private
+   * 如果在回调函数中，emitter_off当前正在dispatch的回调函数，我们只是设置remove_curr_iter为TRUE，在分发完成后才执行。
+   * XXX: 如果要注销当前正在dispatch的回调函数，直接返回RET_REMOVE是最好的选择。
+   */
+  bool_t remove_curr_iter;
+  /**
+   * @property {emitter_item_t*} curr_iter
+   * @private
+   * 当前正在dispatch的项。
+   */
+  emitter_item_t* curr_iter;
 } emitter_t;
 
+/**
+ * @method emitter_create
+ * @constructor
+ * 创建emitter对象。
+ *
+ * @return {emitter_t*} 对象。
+ */
 emitter_t* emitter_create(void);
+
+/**
+ * @method emitter_init
+ * @constructor
+ * 初始化emitter对象。
+ * @param {emitter_t*} emitter emitter对象。
+ *
+ * @return {emitter_t*} 对象。
+ */
 emitter_t* emitter_init(emitter_t* emitter);
+
+/**
+ * @method emitter_dispatch
+ * 分发事件。如果当前分发的回调函数返回RET_REMOVE，该回调函数将被移出。
+ * 禁用状态下，本函数不做任何事情。
+ * @param {emitter_t*} emitter emitter对象。
+ * @param {event_t*} e 事件对象。
+
+ * @return {ret_t}
+ 如果当前分发的回调函数返回RET_STOP，dispatch中断分发，并返回RET_STOP，否则返回RET_OK。
+ */
 ret_t emitter_dispatch(emitter_t* emitter, event_t* e);
 
-uint32_t emitter_on(emitter_t* emitter, uint16_t etype, event_func_t handler, void* ctx);
-ret_t emitter_off(emitter_t* emitter, uint32_t id);
-emitter_item_t* emitter_find(emitter_t* emitter, uint32_t id);
-ret_t emitter_off_by_func(emitter_t* emitter, uint16_t etype, event_func_t handler, void* ctx);
+/**
+ * @method emitter_on
+ * 注册指定事件的处理函数。
+ * @param {emitter_t*} emitter emitter对象。
+ * @param {event_type_t} type 事件类型。
+ * @param {event_func_t} on_event 事件处理函数。
+ * @param {void*} ctx 事件处理函数上下文。
+ *
+ * @return {uint32_t} 返回id，用于emitter_off。
+ */
+uint32_t emitter_on(emitter_t* emitter, uint32_t etype, event_func_t handler, void* ctx);
 
-ret_t emitter_stop(emitter_t* emitter);
+/**
+ * @method emitter_off
+ * 注销指定事件的处理函数。
+ * @param {emitter_t*} emitter emitter对象。
+ * @param {uint32_t} id emitter_on返回的ID。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
+ret_t emitter_off(emitter_t* emitter, uint32_t id);
+
+/**
+ * @method emitter_off_by_func
+ * 注销指定事件的处理函数。
+ * @param {emitter_t*} emitter emitter对象。
+ * @param {event_type_t} type 事件类型。
+ * @param {event_func_t} on_event 事件处理函数。
+ * @param {void*} ctx 事件处理函数上下文。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
+ret_t emitter_off_by_func(emitter_t* emitter, uint32_t etype, event_func_t handler, void* ctx);
+
+/**
+ * @method emitter_find
+ * 通过ID查找emitter_item_t，主要用于辅助测试。
+ * @param {emitter_t*} emitter emitter对象。
+ * @param {uint32_t} id emitter_on返回的ID。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
+emitter_item_t* emitter_find(emitter_t* emitter, uint32_t id);
+
+/**
+ * @method emitter_enable
+ * 启用。
+ * @param {emitter_t*} emitter emitter对象。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
 ret_t emitter_enable(emitter_t* emitter);
+
+/**
+ * @method emitter_disable
+ * 禁用。禁用后emitter_dispatch无效，但可以注册和注销。
+ * @param {emitter_t*} emitter emitter对象。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
 ret_t emitter_disable(emitter_t* emitter);
 
+/**
+ * @method emitter_size
+ * 获取注册的回调函数个数，主要用于辅助测试。
+ * @param {emitter_t*} emitter emitter对象。
+ *
+ * @return {uint32_t} 回调函数个数。
+ */
+uint32_t emitter_size(emitter_t* emitter);
+
+/**
+ * @method emitter_deinit
+ * 析构。
+ * @param {emitter_t*} emitter emitter对象。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
 ret_t emitter_deinit(emitter_t* emitter);
+
+/**
+ * @method emitter_destroy
+ * 销毁。
+ * @param {emitter_t*} emitter emitter对象。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
 ret_t emitter_destroy(emitter_t* emitter);
 
 END_C_DECLS
diff --git a/src/base/types_def.h b/src/base/types_def.h
index a1fa37479..d41225abc 100755
--- a/src/base/types_def.h
+++ b/src/base/types_def.h
@@ -94,6 +94,11 @@ typedef enum _ret_t {
    * 操作完成。
    */
   RET_DONE,
+  /**
+   * @const RET_STOP
+   * 停止后续操作。
+   */
+  RET_STOP,
   /**
    * @const RET_BAD_PARAMS
    * 无效参数。
@@ -236,5 +241,6 @@ typedef float float_t;
 #define TK_MAX_FPS 100
 #define TK_OPACITY_ALPHA 0xfa
 #define TK_TRANSPARENT_ALPHA 0x05
+#define TK_INVALID_ID 0
 
 #endif /*TYPES_DEF_H*/
diff --git a/src/window_animators/vtranslate.inc b/src/window_animators/vtranslate.inc
old mode 100755
new mode 100644
index 4ad3fa2f9..fa59af454
--- a/src/window_animators/vtranslate.inc
+++ b/src/window_animators/vtranslate.inc
@@ -44,8 +44,8 @@ static ret_t window_animator_open_vtranslate_draw_curr(window_animator_t* wa) {
 
 #ifdef WITH_NANOVG
   vgcanvas_t* vg = lcd_get_vgcanvas(c->lcd);
-  vgcanvas_draw_image(vg, &(wa->curr_img), win->x*ratio, win->y*ratio, win->w * ratio, h * ratio, win->x, y, win->w,
-                      h);
+  vgcanvas_draw_image(vg, &(wa->curr_img), win->x * ratio, win->y * ratio, win->w * ratio,
+                      h * ratio, win->x, y, win->w, h);
 #else
   rect_t src;
   rect_t dst;
diff --git a/tests/emitter_test.cc b/tests/emitter_test.cc
index 0a6b2019e..648d79bc7 100644
--- a/tests/emitter_test.cc
+++ b/tests/emitter_test.cc
@@ -15,12 +15,37 @@ static ret_t on_event(void* ctx, event_t* e) {
   return RET_OK;
 }
 
+static ret_t on_remove(void* ctx, event_t* e) {
+  uint32_t* p = (uint32_t*)ctx;
+  *p = *p + 1;
+  (void)e;
+
+  return RET_REMOVE;
+}
+
+static ret_t on_remove_id(void* ctx, event_t* e) {
+  uint32_t id = *((uint32_t*)ctx);
+  emitter_t* emitter = (emitter_t*)e->target;
+
+  emitter_off(emitter, id);
+
+  return RET_REMOVE;
+}
+
+static ret_t on_stop(void* ctx, event_t* e) {
+  uint32_t* p = (uint32_t*)ctx;
+  *p = *p + 1;
+  (void)e;
+
+  return RET_STOP;
+}
+
 TEST(Emitter, basic) {
   event_t e;
   uint32_t n = 0;
   emitter_t emitter;
   emitter_init(&emitter);
-  uint16_t type = 12;
+  uint32_t type = 12;
   e.type = type;
   ASSERT_EQ(emitter_on(NULL, type, on_event, NULL), 0);
   ASSERT_EQ(emitter_on(&emitter, type, NULL, NULL), 0);
@@ -50,3 +75,106 @@ TEST(Emitter, basic) {
 
   emitter_deinit(&emitter);
 }
+
+TEST(Emitter, off) {
+  event_t e;
+  uint32_t n = 0;
+  uint32_t id = 0;
+  uint32_t type = 12;
+  emitter_t* emitter = emitter_create();
+
+  e.type = type;
+
+  id = emitter_on(emitter, type, on_event, &n);
+  ASSERT_EQ(id > TK_INVALID_ID, true);
+  ASSERT_EQ(emitter_size(emitter), 1);
+  ASSERT_EQ(emitter_find(emitter, id) != NULL, true);
+
+  ASSERT_EQ(emitter_off(emitter, id), RET_OK);
+  ASSERT_EQ(emitter_size(emitter), 0);
+  ASSERT_EQ(emitter_find(emitter, id) == NULL, true);
+
+  id = emitter_on(emitter, type, on_event, &n);
+  ASSERT_EQ(id > TK_INVALID_ID, true);
+  ASSERT_EQ(emitter_size(emitter), 1);
+  ASSERT_EQ(emitter_find(emitter, id) != NULL, true);
+
+  id = emitter_on(emitter, type, on_event, &n);
+  ASSERT_EQ(id > TK_INVALID_ID, true);
+  ASSERT_EQ(emitter_size(emitter), 2);
+  ASSERT_EQ(emitter_find(emitter, id) != NULL, true);
+
+  ASSERT_EQ(emitter_off(emitter, id), RET_OK);
+  ASSERT_EQ(emitter_size(emitter), 1);
+
+  emitter_destroy(emitter);
+}
+
+TEST(Emitter, remove) {
+  event_t e;
+  uint32_t n = 0;
+  uint32_t id = 0;
+  uint32_t type = 12;
+  emitter_t* emitter = emitter_create();
+
+  e.type = type;
+
+  id = emitter_on(emitter, type, on_remove, &n);
+  id = emitter_on(emitter, type, on_remove, &n);
+  id = emitter_on(emitter, type, on_remove, &n);
+  id = emitter_on(emitter, type, on_remove, &n);
+
+  n = 0;
+  ASSERT_EQ(emitter_dispatch(emitter, &e), RET_OK);
+  ASSERT_EQ(emitter_size(emitter), 0);
+  ASSERT_EQ(n, 4);
+
+  emitter_destroy(emitter);
+}
+
+TEST(Emitter, stop) {
+  event_t e;
+  uint32_t n = 0;
+  uint32_t id = 0;
+  uint32_t type = 12;
+  emitter_t* emitter = emitter_create();
+
+  e.type = type;
+
+  id = emitter_on(emitter, type, on_stop, &n);
+  id = emitter_on(emitter, type, on_stop, &n);
+  id = emitter_on(emitter, type, on_stop, &n);
+  id = emitter_on(emitter, type, on_stop, &n);
+
+  n = 0;
+  ASSERT_EQ(emitter_size(emitter), 4);
+  ASSERT_EQ(emitter_dispatch(emitter, &e), RET_STOP);
+  ASSERT_EQ(emitter_size(emitter), 4);
+  ASSERT_EQ(n, 1);
+
+  emitter_destroy(emitter);
+}
+
+TEST(Emitter, remove_in_func) {
+  event_t e;
+  uint32_t n = 0;
+  uint32_t id1 = 0;
+  uint32_t id2 = 0;
+  uint32_t type = 12;
+  emitter_t* emitter = emitter_create();
+
+  e.type = type;
+  e.target = emitter;
+
+  id1 = emitter_on(emitter, type, on_event, &n);
+  id2 = emitter_on(emitter, type, on_remove_id, &id1);
+  ASSERT_EQ(emitter_dispatch(emitter, &e), RET_OK);
+  ASSERT_EQ(emitter_size(emitter), 0);
+
+  id1 = emitter_on(emitter, type, on_event, &n);
+  id2 = emitter_on(emitter, type, on_remove_id, &id2);
+  ASSERT_EQ(emitter_dispatch(emitter, &e), RET_OK);
+  ASSERT_EQ(emitter_size(emitter), 1);
+
+  emitter_destroy(emitter);
+}