diff --git a/lerna.json b/lerna.json
index d34e2d45e..97587f84f 100644
--- a/lerna.json
+++ b/lerna.json
@@ -6,5 +6,5 @@
     "packages/core",
     "packages/idraw"
   ],
-  "version": "0.1.1"
+  "version": "0.1.2"
 }
diff --git a/packages/board/package.json b/packages/board/package.json
index 74d5b4c45..18f673bc3 100644
--- a/packages/board/package.json
+++ b/packages/board/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@idraw/board",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "",
   "main": "dist/index.cjs.js",
   "module": "dist/index.es.js",
@@ -23,10 +23,10 @@
   "author": "chenshenhai",
   "license": "MIT",
   "devDependencies": {
-    "@idraw/types": "^0.1.1"
+    "@idraw/types": "^0.1.2"
   },
   "dependencies": {
-    "@idraw/util": "^0.1.1"
+    "@idraw/util": "^0.1.2"
   },
   "publishConfig": {
     "access": "public"
diff --git a/packages/core/examples/features/lib/main.js b/packages/core/examples/features/lib/main.js
index a2f8f5d8f..2b45cff8d 100644
--- a/packages/core/examples/features/lib/main.js
+++ b/packages/core/examples/features/lib/main.js
@@ -18,6 +18,7 @@ const core = new Core(mount, {
   contextWidth: 600,
   contextHeight: 400,
   devicePixelRatio: 4,
+  onlyRender: true,
 }, {
   scrollWrapper: {
     use: true,
@@ -46,6 +47,13 @@ core.on('changeScreen', (data) => {
 core.on('screenSelectElement', (data) => {
   console.log('screenSelectElement: ', data);
 });
+core.on('mouseOverElement', (data) => {
+  console.log('mouseOverElement: ', data);
+});
+core.on('mouseLeaveElement', (data) => {
+  console.log('mouseLeaveElement: ', data);
+});
+
 core.on('screenMoveElementStart', (data) => {
   console.log('screenMoveElementStart: ', data);
 });
diff --git a/packages/core/examples/features/lib/scale.js b/packages/core/examples/features/lib/scale.js
index b41354b6b..5be9e2b0f 100644
--- a/packages/core/examples/features/lib/scale.js
+++ b/packages/core/examples/features/lib/scale.js
@@ -10,9 +10,9 @@ export function doScale(core, scale) {
   }
   input.addEventListener('change', () => {
     const val = input.value * 1;
-    console.log('scale ===', val);
     if (val > 0) {
       core.scale(val);
+      console.log(core.getScreenTransform());
     }
   });
   hasInited = true;
diff --git a/packages/core/examples/features/lib/scroll.js b/packages/core/examples/features/lib/scroll.js
index 1ed6c4dbe..73c9942c1 100644
--- a/packages/core/examples/features/lib/scroll.js
+++ b/packages/core/examples/features/lib/scroll.js
@@ -20,12 +20,14 @@ export function doScroll(core, conf = {}) {
     const val = inputX.value * 1;
     if (val >= 0 || val < 0) {
       core.scrollLeft(val);
+      console.log(core.getScreenTransform());
     }
   });
   inputY.addEventListener('change', () => {
     const val = inputY.value * 1;
     if (val >= 0 || val < 0) {
       core.scrollTop(val);
+      console.log(core.getScreenTransform());
     }
   });
   hasInited = true;
diff --git a/packages/core/package.json b/packages/core/package.json
index eeb5592ca..56f3f17c6 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@idraw/core",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "",
   "main": "dist/index.cjs.js",
   "module": "dist/index.es.js",
@@ -23,11 +23,11 @@
   "author": "chenshenhai",
   "license": "MIT",
   "devDependencies": {
-    "@idraw/types": "^0.1.1"
+    "@idraw/types": "^0.1.2"
   },
   "dependencies": {
-    "@idraw/board": "^0.1.1",
-    "@idraw/util": "^0.1.1"
+    "@idraw/board": "^0.1.2",
+    "@idraw/util": "^0.1.2"
   },
   "publishConfig": {
     "access": "public"
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index b7baf329a..63ef502ab 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -1,7 +1,7 @@
 import {
   TypeData, TypePoint, TypeBoardSizeOptions,
   TypeHelperWrapperDotDirection, TypeConfig, TypeConfigStrict, TypeElementBase,
-  TypeElement, TypeElemDesc, TypeContext, TypeCoreOptions,  TypeScreenContext,
+  TypeElement, TypeElemDesc, TypeContext, TypeCoreOptions,  TypeScreenContext, TypeScreenData,
 }  from '@idraw/types';
 import Board from '@idraw/board';
 import util from '@idraw/util';
@@ -14,9 +14,10 @@ import { CoreEvent, TypeCoreEventArgMap } from './lib/core-event';
 import { parseData } from './lib/parse';
 import is, { TypeIs } from './lib/is';
 import check, { TypeCheck } from './lib/check';
+import { TempData } from './lib/temp';
 import {
   _board, _data, _opts, _config, _renderer, _element, _helper, _hasInited,
-  _mode, _selectedUUID, _selectedUUIDList, _prevPoint, _draw,
+  _mode, _tempData, _prevPoint, _draw,
   _selectedDotDirection, _coreEvent, _mapper, _initEvent, _handlePoint,
   _handleMoveStart, _handleMove, _handleMoveEnd, _handleHover, _dragElements,
   _transfromElement, _emitChangeScreen, _emitChangeData, _onlyRender, _cursorStatus,
@@ -40,8 +41,7 @@ class Core {
   private [_hasInited] = false; 
   private [_mode]: Mode = Mode.NULL;
   private [_coreEvent]: CoreEvent = new CoreEvent();
-  private [_selectedUUID]: string | null = null;
-  private [_selectedUUIDList]: string[] = [];
+  private [_tempData]: TempData;
   private [_prevPoint]: TypePoint | null = null;
   private [_selectedDotDirection]: TypeHelperWrapperDotDirection | null = null;
   private [_onlyRender] = false;
@@ -55,7 +55,7 @@ class Core {
     this[_opts] = opts;
     this[_onlyRender] = opts.onlyRender === true;
     this[_config] = mergeConfig(config || {});
-
+    this[_tempData] = new TempData();
     this[_board] = new Board(mount, {
       ...this[_opts],
       canScroll: config?.scrollWrapper?.use,
@@ -82,8 +82,8 @@ class Core {
       width: this[_opts].width,
       height: this[_opts].height,
       canScroll: this[_config]?.scrollWrapper?.use === true,
-      selectedUUID: this[_selectedUUID],
-      selectedUUIDList: this[_selectedUUIDList],
+      selectedUUID: this[_tempData].get('selectedUUID'),
+      selectedUUIDList: this[_tempData].get('selectedUUIDList'),
       devicePixelRatio: this[_opts].devicePixelRatio,
       scale: transfrom.scale,
       scrollX: transfrom.scrollX,
@@ -108,8 +108,8 @@ class Core {
         this[_mode] = Mode.NULL;
       }
       if (typeof uuid === 'string') {
-        this[_selectedUUID] = uuid;
-        this[_selectedUUIDList] = [];
+        this[_tempData].set('selectedUUID', uuid);
+        this[_tempData].set('selectedUUIDList', []);
       }
       this[_draw]();
     }
@@ -168,6 +168,15 @@ class Core {
     return screen;
   }
 
+  getScreenTransform(): TypeScreenData {
+    const transform = this[_board].getTransform();
+    return {
+      scale: transform.scale,
+      scrollTop: Math.max(0, 0 - transform.scrollY),
+      scrollLeft: Math.max(0, 0 - transform.scrollX),
+    }
+  }
+
   getData(): TypeData {
     return deepClone(this[_data]);
   }
@@ -243,17 +252,18 @@ class Core {
   }
 
   private [_initEvent](): void {
-    if (this[_onlyRender] === true) {
+    if (this[_hasInited] === true) {
       return;
     }
-    if (this[_hasInited] === true) {
+
+    this[_board].on('hover', time.throttle(this[_handleHover].bind(this), 32));
+    if (this[_onlyRender] === true) {
       return;
     }
     this[_board].on('point', this[_handlePoint].bind(this));
     this[_board].on('moveStart', this[_handleMoveStart].bind(this));
     this[_board].on('move', time.throttle(this[_handleMove].bind(this), 16));
     this[_board].on('moveEnd', this[_handleMoveEnd].bind(this));
-    this[_board].on('hover', time.throttle(this[_handleHover].bind(this), 32));
   }
 
   private [_handlePoint](point: TypePoint): void {
@@ -269,7 +279,7 @@ class Core {
         // Controll Element-Wrapper
         this[_mode] = Mode.SELECT_ELEMENT_WRAPPER_DOT;
         this[_selectedDotDirection] = direction;
-        this[_selectedUUID] = uuid;
+        this[_tempData].set('selectedUUID', uuid);
       } else {
         const [index, uuid] = this[_element].isPointInElement(point, this[_data]);
         if (index >= 0) {
@@ -285,7 +295,7 @@ class Core {
           this[_mode] = Mode.SELECT_ELEMENT;
         } else {
           // Controll Area
-          this[_selectedUUIDList] = [];
+          this[_tempData].set('selectedUUIDList', []);
           this[_mode] = Mode.SELECT_AREA;
         }
       }
@@ -296,7 +306,7 @@ class Core {
 
   private [_handleMoveStart](point: TypePoint): void {
     this[_prevPoint] = point;
-    const uuid = this[_selectedUUID];
+    const uuid = this[_tempData].get('selectedUUID');
 
     if (this[_mode] === Mode.SELECT_ELEMENT_LIST) {
       // TODO
@@ -316,16 +326,16 @@ class Core {
 
   private [_handleMove](point: TypePoint): void {
     if (this[_mode] === Mode.SELECT_ELEMENT_LIST) {
-      this[_dragElements](this[_selectedUUIDList], point, this[_prevPoint]);
+      this[_dragElements](this[_tempData].get('selectedUUIDList'), point, this[_prevPoint]);
       this[_draw]();
       this[_cursorStatus] = CursorStatus.DRAGGING;
-    } else if (typeof this[_selectedUUID] === 'string') {
+    } else if (typeof this[_tempData].get('selectedUUID') === 'string') {
       if (this[_mode] === Mode.SELECT_ELEMENT) {
-        this[_dragElements]([this[_selectedUUID] as string], point, this[_prevPoint]);
+        this[_dragElements]([this[_tempData].get('selectedUUID') as string], point, this[_prevPoint]);
         this[_draw]();
         this[_cursorStatus] = CursorStatus.DRAGGING;
       } else if (this[_mode] === Mode.SELECT_ELEMENT_WRAPPER_DOT && this[_selectedDotDirection]) {
-        this[_transfromElement](this[_selectedUUID] as string, point, this[_prevPoint], this[_selectedDotDirection] as TypeHelperWrapperDotDirection);
+        this[_transfromElement](this[_tempData].get('selectedUUID') as string, point, this[_prevPoint], this[_selectedDotDirection] as TypeHelperWrapperDotDirection);
         this[_cursorStatus] = CursorStatus.DRAGGING;
       }
     } else if (this[_mode] === Mode.SELECT_AREA) {
@@ -336,7 +346,7 @@ class Core {
   }
 
   private [_handleMoveEnd](point: TypePoint): void {
-    const uuid = this[_selectedUUID];
+    const uuid = this[_tempData].get('selectedUUID');
     if (typeof uuid === 'string') {
       const index = this[_element].getElementIndex(this[_data], uuid);
       const elem = this[_data].elements[index];
@@ -363,26 +373,45 @@ class Core {
     } else if (this[_mode] === Mode.SELECT_AREA) {
       const uuids = this[_helper].calcSelectedElements(this[_data]);
       if (uuids.length > 0) {
-        this[_selectedUUIDList] = uuids;
-        this[_selectedUUID] = null;
+        this[_tempData].set('selectedUUIDList', uuids);
+        this[_tempData].set('selectedUUID', null);
       } else {
         this[_mode] = Mode.NULL;
       }
       this[_helper].clearSelectedArea();
       this[_draw]();
     }
-    this[_selectedUUID] = null;
+    this[_tempData].set('selectedUUID', null);
     this[_prevPoint] = null;
     this[_cursorStatus] = CursorStatus.NULL;
     this[_mode] = Mode.NULL;
   }
 
   private [_handleHover](point: TypePoint): void {
+    let isMouseOverElement: boolean = false;
+    
     if (this[_mode] === Mode.SELECT_AREA) {
-      this[_board].resetCursor();
+      if (this[_onlyRender] !== true) this[_board].resetCursor();
     } else if (this[_cursorStatus] === CursorStatus.NULL) {
-      const cursor = this[_mapper].judgePointCursor(point, this[_data]);
-      this[_board].setCursor(cursor);
+      const { cursor, elementUUID } = this[_mapper].judgePointCursor(point, this[_data]);
+      if (this[_onlyRender] !== true) this[_board].setCursor(cursor);
+      if (elementUUID) {
+        const index: number | null = this[_helper].getElementIndexByUUID(elementUUID);
+        if (index !== null && index >= 0) {
+          const elem = this[_data].elements[index];
+          if (elem) {
+            this[_coreEvent].trigger('mouseOverElement', { index, uuid: elem.uuid, element: elem, });
+            this[_tempData].set('hoverUUID', elem.uuid);
+            isMouseOverElement = true;
+          }
+        }
+      }
+    }
+    if (isMouseOverElement !== true && this[_tempData].get('hoverUUID') !== null) {
+      const uuid = this[_tempData].get('hoverUUID');
+      const index: number | null = this[_helper].getElementIndexByUUID(uuid || '');
+      this[_coreEvent].trigger('mouseLeaveElement', { uuid, index })
+      this[_tempData].set('hoverUUID', null); 
     }
   }
 
@@ -419,10 +448,10 @@ class Core {
   private [_emitChangeScreen]() {
     if (this[_coreEvent].has('changeScreen')) {
       this[_coreEvent].trigger('changeScreen', {
-        ...this[_board].getTransform(),
-        ...{
-          selectedElementUUID: this[_selectedUUID]
-        }
+        ...this.getScreenTransform(),
+        // ...{
+        //   selectedElementUUID: this[_tempData].get('selectedUUID')
+        // }
       });
     }
   }
diff --git a/packages/core/src/lib/core-event.ts b/packages/core/src/lib/core-event.ts
index 99feae7b3..d22040683 100644
--- a/packages/core/src/lib/core-event.ts
+++ b/packages/core/src/lib/core-event.ts
@@ -7,12 +7,14 @@ import {
 } from '@idraw/types';
 
 export type TypeCoreEventSelectBaseArg = {
-  index: number;
-  uuid: string;
+  index: number | null;
+  uuid: string | null;
 }
 
 export type TypeCoreEventArgMap  = {
   'error': any;
+  'mouseOverElement': TypeCoreEventSelectBaseArg & { element: TypeElement<keyof TypeElemDesc> }
+  'mouseLeaveElement': TypeCoreEventSelectBaseArg;
   'screenSelectElement': TypeCoreEventSelectBaseArg & { element: TypeElement<keyof TypeElemDesc> }
   'screenMoveElementStart': TypeCoreEventSelectBaseArg & TypePoint,
   'screenMoveElementEnd': TypeCoreEventSelectBaseArg & TypePoint,
diff --git a/packages/core/src/lib/loader.ts b/packages/core/src/lib/loader.ts
index 882a913f7..a681ad510 100644
--- a/packages/core/src/lib/loader.ts
+++ b/packages/core/src/lib/loader.ts
@@ -254,29 +254,35 @@ export default class Loader {
 
           loadUUIDList.splice(loadUUIDList.indexOf(uuid), 1);
           const status = _loadAction();
-        
-          this._storageLoadData[uuid] = {
-            type: this._currentLoadData[uuid].type,
-            status: 'fail',
-            content: null,
-            error: err,
-            source: this._currentLoadData[uuid].source,
-            elemW: this._currentLoadData[uuid].elemW,
-            elemH: this._currentLoadData[uuid].elemH,
-          };
+
+          if (this._currentLoadData[uuid]) {
+            this._storageLoadData[uuid] = {
+              type: this._currentLoadData[uuid]?.type,
+              status: 'fail',
+              content: null,
+              error: err,
+              source: this._currentLoadData[uuid]?.source,
+              elemW: this._currentLoadData[uuid]?.elemW,
+              elemH: this._currentLoadData[uuid]?.elemH,
+            };
+          }
 
           if (loadUUIDList.length === 0 && uuids.length === 0 && status === true) {
             this._status = LoaderStatus.FREE;
             this._loadTask();
           } 
-          this._event.trigger('error', {
-            type: this._storageLoadData[uuid].type,
-            status: this._storageLoadData[uuid].status,
-            content: this._storageLoadData[uuid].content,
-            source: this._storageLoadData[uuid].source,
-            elemW: this._storageLoadData[uuid].elemW,
-            elemH: this._storageLoadData[uuid].elemH,
-          });
+          
+          if (this._currentLoadData[uuid]) {
+            this._event.trigger('error', {
+              type: this._storageLoadData[uuid]?.type,
+              status: this._storageLoadData[uuid]?.status,
+              content: this._storageLoadData[uuid]?.content,
+              source: this._storageLoadData[uuid]?.source,
+              elemW: this._storageLoadData[uuid]?.elemW,
+              elemH: this._storageLoadData[uuid]?.elemH,
+            });
+          }
+          
         });
  
       }
diff --git a/packages/core/src/lib/mapper.ts b/packages/core/src/lib/mapper.ts
index b15a2ec30..ef7592018 100644
--- a/packages/core/src/lib/mapper.ts
+++ b/packages/core/src/lib/mapper.ts
@@ -37,10 +37,14 @@ export class Mapper {
     return false;
   }
 
-  judgePointCursor(p: TypePoint, data: TypeData): TypePointCursor {
+  judgePointCursor(p: TypePoint, data: TypeData): {
+    cursor: TypePointCursor,
+    elementUUID: string | null,
+  } {
     let cursor: TypePointCursor = 'auto';
+    let elementUUID: string | null = null;
     if (!this.isEffectivePoint(p)) {
-      return cursor;
+      return { cursor, elementUUID};
     }
     const [uuid, direction] = this[_helper].isPointInElementWrapperDot(p);
     if (uuid && direction) {
@@ -85,13 +89,22 @@ export class Mapper {
           break;
         }
       }
+      if (uuid) {
+        elementUUID = uuid;
+      }
     } else {
-      const [index] = this[_element].isPointInElement(p, data);
+      const [index, uuid] = this[_element].isPointInElement(p, data);
       if (index >= 0) {
         cursor = 'move';
       }
+      if (uuid) {
+        elementUUID = uuid;
+      }
     }
-    return cursor;
+    return {
+      cursor,
+      elementUUID,
+    };
   }
 
 }
diff --git a/packages/core/src/lib/temp.ts b/packages/core/src/lib/temp.ts
new file mode 100644
index 000000000..a3e289063
--- /dev/null
+++ b/packages/core/src/lib/temp.ts
@@ -0,0 +1,36 @@
+
+type TempDataDesc = {
+  selectedUUID: string | null,
+  selectedUUIDList: string[],
+  hoverUUID: string | null,
+}
+
+
+export class TempData {
+
+  private _temp: TempDataDesc
+
+  constructor() {
+    this._temp = {
+      selectedUUID: null,
+      selectedUUIDList: [],
+      hoverUUID: null,
+    }
+  }
+
+  set<T extends keyof TempDataDesc >(name: T, value:  TempDataDesc[T]) {
+    this._temp[name] = value;
+  }
+
+  get<T extends keyof TempDataDesc >(name: T): TempDataDesc[T] {
+    return this._temp[name];
+  }
+
+  clear() {
+    this._temp = {
+      selectedUUID: null,
+      hoverUUID: null,
+      selectedUUIDList: [],
+    }
+  }
+}
\ No newline at end of file
diff --git a/packages/core/src/names.ts b/packages/core/src/names.ts
index bfff74f6a..c103371ef 100644
--- a/packages/core/src/names.ts
+++ b/packages/core/src/names.ts
@@ -7,8 +7,7 @@ const _element = Symbol('_element');
 const _helper = Symbol('_helper');
 const _hasInited = Symbol('_hasInited');
 const _mode = Symbol('_mode');
-const _selectedUUID = Symbol('_selectedUUID');
-const _selectedUUIDList = Symbol('_selectedUUIDList');
+const _tempData = Symbol('_tempData');
 const _prevPoint = Symbol('_prevPoint');
 const _draw = Symbol('_draw');
 const _selectedDotDirection = Symbol('_selectedDotDirection');
@@ -29,7 +28,7 @@ const _cursorStatus = Symbol('_cursorStatus');
 
 export {
   _board, _data, _opts, _config, _renderer, _element, _helper, _hasInited,
-  _mode, _selectedUUID, _selectedUUIDList, _prevPoint, _draw,
+  _mode, _tempData, _prevPoint, _draw,
   _selectedDotDirection, _coreEvent, _mapper, _initEvent, _handlePoint,
   _handleMoveStart, _handleMove, _handleMoveEnd, _handleHover, _dragElements,
   _transfromElement, _emitChangeScreen, _emitChangeData, _onlyRender, _cursorStatus,
diff --git a/packages/idraw/package.json b/packages/idraw/package.json
index d94a1215c..d8be21d1c 100644
--- a/packages/idraw/package.json
+++ b/packages/idraw/package.json
@@ -1,6 +1,6 @@
 {
   "name": "idraw",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "",
   "main": "dist/index.cjs.js",
   "module": "dist/index.es.js",
@@ -23,10 +23,10 @@
   "author": "chenshenhai",
   "license": "MIT",
   "devDependencies": {
-    "@idraw/types": "^0.1.1"
+    "@idraw/types": "^0.1.2"
   },
   "dependencies": {
-    "@idraw/core": "^0.1.1"
+    "@idraw/core": "^0.1.2"
   },
   "publishConfig": {
     "access": "public"
diff --git a/packages/types/package.json b/packages/types/package.json
index e1ec105b9..79f33ba5c 100644
--- a/packages/types/package.json
+++ b/packages/types/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@idraw/types",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "",
   "main": "src/index.ts",
   "types": "src/index.ts",
diff --git a/packages/types/src/lib/screen.ts b/packages/types/src/lib/screen.ts
index 89ac7000e..10f6bb3ec 100644
--- a/packages/types/src/lib/screen.ts
+++ b/packages/types/src/lib/screen.ts
@@ -1,8 +1,8 @@
 type TypeScreenData = {
   scale: number;
-  scrollY: number;
-  scrollX: number;
-  selectedElementUUID: string | null;
+  scrollLeft: number;
+  scrollTop: number;
+  // selectedElementUUID: string | null;
 }
 
 type TypeScreenPosition = {
diff --git a/packages/util/package.json b/packages/util/package.json
index 8897cb963..3adedcf4d 100644
--- a/packages/util/package.json
+++ b/packages/util/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@idraw/util",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "",
   "main": "dist/index.cjs.js",
   "module": "dist/index.es.js",