diff --git a/docs/todo/core.md b/docs/todo/core.md
index c07d1d6..d3d24bc 100644
--- a/docs/todo/core.md
+++ b/docs/todo/core.md
@@ -1,10 +1,10 @@
 # @idraw/core
 
-* [] BUG: Select area calculate elements error
 * [] Support gradient color
-* [] Move elements that in selected-area
 * [] Listen keyboard action
 * [] Keep all num two decimals
+* [x] BUG: Select area calculate elements error
+* [x] Move elements that in selected-area
 * [x] Area select
 * [x] Lock Element
 * [x] FireFox's Compatibility Question (And Safair Browser) 
diff --git a/packages/board/__tests__/point.test.ts b/packages/board/__tests__/point.test.ts
index 1c24bdf..ae8cc61 100644
--- a/packages/board/__tests__/point.test.ts
+++ b/packages/board/__tests__/point.test.ts
@@ -2,7 +2,6 @@ import Board from '../src';
 
 describe('@idraw/board', () => {
 
-
   document.body.innerHTML = `
     <div id="mount"></div>
   `;
@@ -22,20 +21,21 @@ describe('@idraw/board', () => {
   const mount = document.querySelector('#mount') as HTMLDivElement;
   const board = new Board(mount, opts);
 
-  test('scroll', async () => {  
-    
-    board.scale(transform.scale);
-    board.scrollX(transform.scrollX);
-    board.scrollY(transform.scrollY);
-    board.draw();
+  board.scale(transform.scale);
+  board.scrollX(transform.scrollX);
+  board.scrollY(transform.scrollY);
+  board.draw();
 
-    const p1 = {x: 400, y: 300};
-    const p2 = {x: 300, y: 200};
+  const p1 = {x: 400, y: 300};
+  const p2 = {x: 300, y: 200};
 
+  test('pointScreenToContext', async () => {
     expect(board.pointScreenToContext(p1)).toStrictEqual(p2);
+  });
+
+  test('pointContextToScreen', async () => {
     expect(board.pointContextToScreen(p2)).toStrictEqual(p1);
   });
 
-
 });
 
diff --git a/packages/core/__tests__/lib/point.test.ts b/packages/core/__tests__/lib/point.test.ts
new file mode 100644
index 0000000..5436e85
--- /dev/null
+++ b/packages/core/__tests__/lib/point.test.ts
@@ -0,0 +1,41 @@
+import IDraw from '../../src';
+
+describe('@idraw/core', () => {
+
+  document.body.innerHTML = `
+    <div id="mount"></div>
+  `;
+  const opts = {
+    width: 800,
+    height: 600,
+    contextWidth: 600,
+    contextHeight: 400,
+    devicePixelRatio: 4,
+    canScroll: true,
+  };
+  const transform = {
+    scale: 2,
+    scrollX: -200,
+    scrollY: -100,
+  };
+  const mount = document.querySelector('#mount') as HTMLDivElement;
+  const idraw = new IDraw(mount, opts);
+
+  idraw.scale(transform.scale);
+  idraw.scrollX(transform.scrollX);
+  idraw.scrollY(transform.scrollY);
+  idraw.draw();
+
+  const p1 = {x: 400, y: 300};
+  const p2 = {x: 300, y: 200};
+
+  test('pointScreenToContext', async () => {
+    expect(idraw.pointScreenToContext(p1)).toStrictEqual(p2);
+  });
+
+  test('pointContextToScreen', async () => {
+    expect(idraw.pointContextToScreen(p2)).toStrictEqual(p1);
+  });
+
+});
+
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 2fb4675..5a53ca3 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -224,6 +224,14 @@ class Core {
     this[_coreEvent].off(key, callback);
   }
 
+  pointScreenToContext(p: TypePoint) {
+    return this[_board].pointScreenToContext(p);
+  }
+
+  pointContextToScreen(p: TypePoint) {
+    return this[_board].pointContextToScreen(p);
+  }
+
   __getBoardContext(): TypeContext {
     return this[_board].getContext();
   }
diff --git a/packages/core/src/lib/helper.ts b/packages/core/src/lib/helper.ts
index 0580400..c1bb8f8 100644
--- a/packages/core/src/lib/helper.ts
+++ b/packages/core/src/lib/helper.ts
@@ -21,8 +21,8 @@ export class Helper implements TypeHelper {
   private _coreConfig: TypeConfigStrict;
   private _ctx: TypeContext;
   private _board: Board;
-  private _areaStart: TypePoint = { x: 0, y: 0};
-  private _areaEnd: TypePoint = { x: 0, y: 0};
+  private _areaStart: TypePoint = { x: 0, y: 0 };
+  private _areaEnd: TypePoint = { x: 0, y: 0 };
 
   constructor(board: Board, config: TypeConfigStrict) {
     this._board = board;