diff --git a/examples/candle_chart/run.py b/examples/candle_chart/run.py
new file mode 100644
index 00000000..c4114cb9
--- /dev/null
+++ b/examples/candle_chart/run.py
@@ -0,0 +1,41 @@
+from datetime import datetime
+
+from vnpy.trader.ui import create_qapp, QtCore
+from vnpy.trader.database import database_manager
+from vnpy.trader.constant import Exchange, Interval
+from vnpy.chart import ChartWidget, VolumeItem, CandleItem
+
+if __name__ == "__main__":
+    app = create_qapp()
+
+    bars = database_manager.load_bar_data(
+        "IF88",
+        Exchange.CFFEX,
+        interval=Interval.MINUTE,
+        start=datetime(2019, 7, 1),
+        end=datetime(2019, 7, 17)
+    )
+
+    widget = ChartWidget()
+    widget.add_plot("candle", hide_x_axis=True)
+    widget.add_plot("volume", maximum_height=200)
+    widget.add_item(CandleItem, "candle", "candle")
+    widget.add_item(VolumeItem, "volume", "volume")
+    widget.add_cursor()
+
+    n = 1000
+    history = bars[:n]
+    new_data = bars[n:]
+
+    widget.update_history(history)
+
+    def update_bar():
+        bar = new_data.pop(0)
+        widget.update_bar(bar)
+
+    timer = QtCore.QTimer()
+    timer.timeout.connect(update_bar)
+    timer.start(100)
+
+    widget.show()
+    app.exec_()
diff --git a/examples/vn_trader/run.py b/examples/vn_trader/run.py
index 32d3596e..7c1ccf8e 100644
--- a/examples/vn_trader/run.py
+++ b/examples/vn_trader/run.py
@@ -8,7 +8,7 @@ from vnpy.trader.ui import MainWindow, create_qapp
 # from vnpy.gateway.bitmex import BitmexGateway
 # from vnpy.gateway.futu import FutuGateway
 # from vnpy.gateway.ib import IbGateway
-# from vnpy.gateway.ctp import CtpGateway
+from vnpy.gateway.ctp import CtpGateway
 # from vnpy.gateway.ctptest import CtptestGateway
 # from vnpy.gateway.mini import MiniGateway
 # from vnpy.gateway.femas import FemasGateway
@@ -44,7 +44,7 @@ def main():
     main_engine = MainEngine(event_engine)
 
     # main_engine.add_gateway(BinanceGateway)
-    # main_engine.add_gateway(CtpGateway)
+    main_engine.add_gateway(CtpGateway)
     # main_engine.add_gateway(CtptestGateway)
     # main_engine.add_gateway(MiniGateway)
     # main_engine.add_gateway(FemasGateway)
diff --git a/vnpy/chart/__init__.py b/vnpy/chart/__init__.py
new file mode 100644
index 00000000..4d090ff4
--- /dev/null
+++ b/vnpy/chart/__init__.py
@@ -0,0 +1,2 @@
+from .widget import ChartWidget
+from .item import CandleItem, VolumeItem
diff --git a/vnpy/chart/axis.py b/vnpy/chart/axis.py
new file mode 100644
index 00000000..6a63d990
--- /dev/null
+++ b/vnpy/chart/axis.py
@@ -0,0 +1,44 @@
+from typing import List
+
+import pyqtgraph as pg
+
+from vnpy.trader.ui import QtGui
+
+from .manager import BarManager
+
+
+AXIS_WIDTH = 0.8
+AXIS_FONT = QtGui.QFont("Arial", 10, QtGui.QFont.Bold)
+
+
+class DatetimeAxis(pg.AxisItem):
+    """"""
+
+    def __init__(self, manager: BarManager, *args, **kwargs):
+        """"""
+        super().__init__(*args, **kwargs)
+
+        self._manager: BarManager = manager
+
+        self.setPen(width=AXIS_WIDTH)
+        self.setStyle(tickFont=AXIS_FONT, autoExpandTextSpace=True)
+
+    def tickStrings(self, values: List[int], scale: float, spacing: int):
+        """
+        Convert original index to datetime string.
+        """
+        strings = []
+
+        for ix in values:
+            dt = self._manager.get_datetime(ix)
+
+            if not dt:
+                s = ""
+            elif dt.hour:
+                s = dt.strftime("%Y-%m-%d\n%H:%M:%S")
+            else:
+                s = dt.strftime("%Y-%m-%d")
+
+            strings.append(s)
+
+        return strings
diff --git a/vnpy/chart/base.py b/vnpy/chart/base.py
new file mode 100644
index 00000000..629a1fec
--- /dev/null
+++ b/vnpy/chart/base.py
@@ -0,0 +1,15 @@
+WHITE_COLOR = (255, 255, 255)
+BLACK_COLOR = (0, 0, 0)
+GREY_COLOR = (100, 100, 100)
+
+UP_COLOR = (255, 0, 0)
+DOWN_COLOR = (0, 255, 50)
+CURSOR_COLOR = (255, 245, 162)
+
+PEN_WIDTH = 1
+BAR_WIDTH = 0.4
+
+
+def to_int(value: float) -> int:
+    """"""
+    return int(round(value, 0))
diff --git a/vnpy/chart/item.py b/vnpy/chart/item.py
new file mode 100644
index 00000000..e1435ccc
--- /dev/null
+++ b/vnpy/chart/item.py
@@ -0,0 +1,260 @@
+from abc import abstractmethod
+from typing import List, Dict, Tuple
+
+import pyqtgraph as pg
+
+from vnpy.trader.ui import QtCore, QtGui, QtWidgets
+from vnpy.trader.object import BarData
+
+from .base import UP_COLOR, DOWN_COLOR, PEN_WIDTH, BAR_WIDTH
+from .manager import BarManager
+
+
+class ChartItem(pg.GraphicsObject):
+    """"""
+
+    def __init__(self, manager: BarManager):
+        """"""
+        super().__init__()
+
+        self._manager: BarManager = manager
+
+        self._bar_picutures: Dict[int, QtGui.QPicture] = {}
+        self._item_picuture: QtGui.QPicture = None
+
+        self._up_pen: QtGui.QPen = pg.mkPen(
+            color=UP_COLOR, width=PEN_WIDTH
+        )
+        self._up_brush: QtGui.QBrush = pg.mkBrush(color=UP_COLOR)
+
+        self._down_pen: QtGui.QPen = pg.mkPen(
+            color=DOWN_COLOR, width=PEN_WIDTH
+        )
+        self._down_brush: QtGui.QBrush = pg.mkBrush(color=DOWN_COLOR)
+
+    @abstractmethod
+    def _draw_bar_picture(self, ix: int, bar: BarData) -> QtGui.QPicture:
+        """
+        Draw picture for specific bar.
+        """
+        pass
+
+    @abstractmethod
+    def boundingRect(self) -> QtCore.QRectF:
+        """
+        Get bounding rectangles for item.
+        """
+        pass
+
+    @abstractmethod
+    def get_y_range(self, min_ix: int = None, max_ix: int = None) -> Tuple[float, float]:
+        """
+        Get range of y-axis with given x-axis range.
+
+        If min_ix and max_ix not specified, then return range with whole data set.
+        """
+        pass
+
+    def update_history(self, history: List[BarData]) -> BarData:
+        """
+        Update a list of bar data.
+        """
+        self._bar_picutures.clear()
+
+        bars = self._manager.get_all_bars()
+        for ix, bar in enumerate(bars):
+            bar_picture = self._draw_bar_picture(ix, bar)
+            self._bar_picutures[ix] = bar_picture
+
+        self.update()
+
+    def update_bar(self, bar: BarData) -> BarData:
+        """
+        Update single bar data.
+        """
+        ix = self._manager.get_index(bar.datetime)
+
+        bar_picture = self._draw_bar_picture(ix, bar)
+        self._bar_picutures[ix] = bar_picture
+
+        self.update()
+
+    def update(self) -> None:
+        """
+        Refresh the item.
+        """
+        if self.scene():
+            self.scene().update()
+
+    def paint(
+        self,
+        painter: QtGui.QPainter,
+        opt: QtWidgets.QStyleOptionGraphicsItem,
+        w: QtWidgets.QWidget
+    ):
+        """
+        Reimplement the paint method of parent class.
+
+        This function is called by external QGraphicsView.
+        """
+        rect = opt.exposedRect
+
+        min_ix = int(rect.left())
+        max_ix = int(rect.right())
+        max_ix = min(max_ix, len(self._bar_picutures))
+        self._draw_item_picture(min_ix, max_ix)
+
+        self._item_picuture.play(painter)
+
+    def _draw_item_picture(self, min_ix: int, max_ix: int) -> None:
+        """
+        Draw the picture of item in specific range.
+        """
+        self._item_picuture = QtGui.QPicture()
+        painter = QtGui.QPainter(self._item_picuture)
+
+        for n in range(min_ix, max_ix):
+            bar_picture = self._bar_picutures[n]
+            bar_picture.play(painter)
+
+        painter.end()
+
+    def clear_all(self) -> None:
+        """
+        Clear all data in the item.
+        """
+        self._item_picuture = None
+        self._bar_picutures.clear()
+        self.update()
+
+
+class CandleItem(ChartItem):
+    """"""
+
+    def __init__(self, manager: BarManager):
+        """"""
+        super().__init__(manager)
+
+    def _draw_bar_picture(self, ix: int, bar: BarData) -> QtGui.QPicture:
+        """"""
+        # Create objects
+        candle_picture = QtGui.QPicture()
+        painter = QtGui.QPainter(candle_picture)
+
+        # Set painter color
+        if bar.close_price >= bar.open_price:
+            painter.setPen(self._up_pen)
+            painter.setBrush(self._up_brush)
+        else:
+            painter.setPen(self._down_pen)
+            painter.setBrush(self._down_brush)
+
+        # Draw candle body
+        if bar.open_price == bar.close_price:
+            painter.drawLine(
+                QtCore.QPointF(ix - BAR_WIDTH, bar.open_price),
+                QtCore.QPointF(ix + BAR_WIDTH, bar.open_price),
+            )
+        else:
+            rect = QtCore.QRectF(
+                ix - BAR_WIDTH,
+                bar.open_price,
+                BAR_WIDTH * 2,
+                bar.close_price - bar.open_price
+            )
+            painter.drawRect(rect)
+
+        # Draw candle shadow
+        body_bottom = min(bar.open_price, bar.close_price)
+        body_top = max(bar.open_price, bar.close_price)
+
+        if bar.low_price < body_bottom:
+            painter.drawLine(
+                QtCore.QPointF(ix, bar.low_price),
+                QtCore.QPointF(ix, body_bottom),
+            )
+
+        if bar.high_price > body_top:
+            painter.drawLine(
+                QtCore.QPointF(ix, bar.high_price),
+                QtCore.QPointF(ix, body_top),
+            )
+
+        # Finish
+        painter.end()
+        return candle_picture
+
+    def boundingRect(self) -> QtCore.QRectF:
+        """"""
+        min_price, max_price = self._manager.get_price_range()
+        rect = QtCore.QRectF(
+            0,
+            min_price,
+            len(self._bar_picutures),
+            max_price - min_price
+        )
+        return rect
+
+    def get_y_range(self, min_ix: int = None, max_ix: int = None) -> Tuple[float, float]:
+        """
+        Get range of y-axis with given x-axis range.
+
+        If min_ix and max_ix not specified, then return range with whole data set.
+        """
+        min_price, max_price = self._manager.get_price_range(min_ix, max_ix)
+        return min_price, max_price
+
+
+class VolumeItem(ChartItem):
+    """"""
+
+    def __init__(self, manager: BarManager):
+        """"""
+        super().__init__(manager)
+
+    def _draw_bar_picture(self, ix: int, bar: BarData) -> QtGui.QPicture:
+        """"""
+        # Create objects
+        volume_picture = QtGui.QPicture()
+        painter = QtGui.QPainter(volume_picture)
+
+        # Set painter color
+        if bar.close_price >= bar.open_price:
+            painter.setPen(self._up_pen)
+            painter.setBrush(self._up_brush)
+        else:
+            painter.setPen(self._down_pen)
+            painter.setBrush(self._down_brush)
+
+        # Draw volume body
+        rect = QtCore.QRectF(
+            ix - BAR_WIDTH,
+            0,
+            BAR_WIDTH * 2,
+            bar.volume
+        )
+        painter.drawRect(rect)
+
+        # Finish
+        painter.end()
+        return volume_picture
+
+    def boundingRect(self) -> QtCore.QRectF:
+        """"""
+        min_volume, max_volume = self._manager.get_volume_range()
+        rect = QtCore.QRectF(
+            0,
+            min_volume,
+            len(self._bar_picutures),
+            max_volume - min_volume
+        )
+        return rect
+
+    def get_y_range(self, min_ix: int = None, max_ix: int = None) -> Tuple[float, float]:
+        """
+        Get range of y-axis with given x-axis range.
+
+        If min_ix and max_ix not specified, then return range with whole data set.
+        """
+        min_volume, max_volume = self._manager.get_volume_range(min_ix, max_ix)
+        return min_volume, max_volume
diff --git a/vnpy/chart/manager.py b/vnpy/chart/manager.py
new file mode 100644
index 00000000..a786eed6
--- /dev/null
+++ b/vnpy/chart/manager.py
@@ -0,0 +1,168 @@
+from typing import Dict, List, Tuple
+from datetime import datetime
+
+from vnpy.trader.object import BarData
+
+from .base import to_int
+
+
+class BarManager:
+    """"""
+
+    def __init__(self):
+        """"""
+        self._bars: Dict[datetime, BarData] = {}
+        self._datetime_index_map: Dict[datetime, int] = {}
+        self._index_datetime_map: Dict[int, datetime] = {}
+
+        self._price_ranges: Dict[Tuple[int, int], Tuple[float, float]] = {}
+        self._volume_ranges: Dict[Tuple[int, int], Tuple[float, float]] = {}
+
+    def update_history(self, history: List[BarData]) -> None:
+        """
+        Update a list of bar data.
+        """
+        # Put all new bars into dict
+        for bar in history:
+            self._bars[bar.datetime] = bar
+
+        # Sort bars dict according to bar.datetime
+        self._bars = dict(sorted(self._bars.items(), key=lambda tp: tp[0]))
+
+        # Update map relationiship
+        ix_list = range(len(self._bars))
+        dt_list = self._bars.keys()
+
+        self._datetime_index_map = dict(zip(dt_list, ix_list))
+        self._index_datetime_map = dict(zip(ix_list, dt_list))
+
+        # Clear data range cache
+        self._clear_cache()
+
+    def update_bar(self, bar: BarData) -> None:
+        """
+        Update one single bar data.
+        """
+        dt = bar.datetime
+
+        if dt not in self._datetime_index_map:
+            ix = len(self._bars)
+            self._datetime_index_map[dt] = ix
+            self._index_datetime_map[ix] = dt
+
+        self._bars[dt] = bar
+
+        self._clear_cache()
+
+    def get_count(self) -> int:
+        """
+        Get total number of bars.
+        """
+        return len(self._bars)
+
+    def get_index(self, dt: datetime) -> int:
+        """
+        Get index with datetime.
+        """
+        return self._datetime_index_map.get(dt, None)
+
+    def get_datetime(self, ix: float) -> datetime:
+        """
+        Get datetime with index.
+        """
+        ix = to_int(ix)
+        return self._index_datetime_map.get(ix, None)
+
+    def get_bar(self, ix: float) -> BarData:
+        """
+        Get bar data with index.
+        """
+        ix = to_int(ix)
+        dt = self._index_datetime_map.get(ix, None)
+        if not dt:
+            return None
+
+        return self._bars[dt]
+
+    def get_all_bars(self) -> List[BarData]:
+        """
+        Get all bar data.
+        """
+        return list(self._bars.values())
+
+    def get_price_range(self, min_ix: float = None, max_ix: float = None) -> Tuple[float, float]:
+        """
+        Get price range to show within given index range.
+        """
+        if not self._bars:
+            return 0, 1
+
+        if not min_ix:
+            min_ix = 0
+            max_ix = len(self._bars) - 1
+        else:
+            min_ix = to_int(min_ix)
+            max_ix = to_int(max_ix)
+            max_ix = min(max_ix, self.get_count())
+
+        buf = self._price_ranges.get((min_ix, max_ix), None)
+        if buf:
+            return buf
+
+        bar_list = list(self._bars.values())[min_ix:max_ix + 1]
+        first_bar = bar_list[0]
+        max_price = first_bar.high_price
+        min_price = first_bar.low_price
+
+        for bar in bar_list[1:]:
+            max_price = max(max_price, bar.high_price)
+            min_price = min(min_price, bar.low_price)
+
+        return min_price, max_price
+
+    def get_volume_range(self, min_ix: float = None, max_ix: float = None) -> Tuple[float, float]:
+        """
+        Get volume range to show within given index range.
+        """
+        if not self._bars:
+            return 0, 1
+
+        if not min_ix:
+            min_ix = 0
+            max_ix = len(self._bars) - 1
+        else:
+            min_ix = to_int(min_ix)
+            max_ix = to_int(max_ix)
+            max_ix = min(max_ix, self.get_count())
+
+        buf = self._volume_ranges.get((min_ix, max_ix), None)
+        if buf:
+            return buf
+
+        bar_list = list(self._bars.values())[min_ix:max_ix + 1]
+
+        first_bar = bar_list[0]
+        max_volume = first_bar.volume
+        min_volume = 0
+
+        for bar in bar_list[1:]:
+            max_volume = max(max_volume, bar.volume)
+
+        return min_volume, max_volume
+
+    def _clear_cache(self) -> None:
+        """
+        Clear cached range data.
+        """
+        self._price_ranges.clear()
+        self._volume_ranges.clear()
+
+    def clear_all(self) -> None:
+        """
+        Clear all data in manager.
+        """
+        self._bars.clear()
+        self._datetime_index_map.clear()
+        self._index_datetime_map.clear()
+
+        self._clear_cache()
diff --git a/vnpy/chart/widget.py b/vnpy/chart/widget.py
new file mode 100644
index 00000000..8ec3a044
--- /dev/null
+++ b/vnpy/chart/widget.py
@@ -0,0 +1,508 @@
+from typing import List, Dict, Type
+
+import pyqtgraph as pg
+
+from vnpy.trader.ui import QtGui, QtWidgets, QtCore
+from vnpy.trader.object import BarData
+
+from .manager import BarManager
+from .base import GREY_COLOR, WHITE_COLOR, CURSOR_COLOR, BLACK_COLOR, to_int
+from .axis import DatetimeAxis, AXIS_FONT
+from .item import ChartItem
+
+
+class ChartWidget(pg.PlotWidget):
+    """"""
+    MIN_BAR_COUNT = 100
+
+    def __init__(self, parent: QtWidgets.QWidget = None):
+        """"""
+        super().__init__(parent)
+
+        self._manager: BarManager = BarManager()
+
+        self._plots: Dict[str, ChartItem] = {}
+        self._items: Dict[str, pg.GraphicsObject] = {}
+        self._item_plot_map: Dict[ChartItem, pg.GraphicsObject] = {}
+
+        self._first_plot: pg.PlotItem = None
+        self._cursor: ChartCursor = None
+
+        self._right_ix: int = 0                     # Index of most right data
+        self._bar_count: int = self.MIN_BAR_COUNT   # Total bar visible in chart
+
+        self._init_ui()
+
+    def _init_ui(self) -> None:
+        """"""
+        self.setWindowTitle("ChartWidget of vn.py")
+
+        self._layout = pg.GraphicsLayout()
+        self._layout.setContentsMargins(10, 10, 10, 10)
+        self._layout.setSpacing(0)
+        self._layout.setBorder(color=GREY_COLOR, width=0.8)
+        self._layout.setZValue(0)
+        self.setCentralItem(self._layout)
+
+        self._x_axis = DatetimeAxis(self._manager, orientation='bottom')
+
+    def add_cursor(self) -> None:
+        """"""
+        if not self._cursor:
+            self._cursor = ChartCursor(self, self._manager, self._plots)
+
+    def add_plot(
+        self,
+        plot_name: str,
+        minimum_height: int = 80,
+        maximum_height: int = None,
+        hide_x_axis: bool = False
+    ) -> None:
+        """
+        Add plot area.
+        """
+        # Create plot object
+        plot = pg.PlotItem(axisItems={'bottom': self._x_axis})
+        plot.setMenuEnabled(False)
+        plot.setClipToView(True)
+        plot.hideAxis('left')
+        plot.showAxis('right')
+        plot.setDownsampling(mode='peak')
+        plot.setRange(xRange=(0, 1), yRange=(0, 1))
+        plot.hideButtons()
+        plot.setMinimumHeight(minimum_height)
+
+        if maximum_height:
+            plot.setMaximumHeight(maximum_height)
+
+        if hide_x_axis:
+            plot.hideAxis("bottom")
+
+        if not self._first_plot:
+            self._first_plot = plot
+
+        # Connect view change signal to update y range function
+        view = plot.getViewBox()
+        view.sigXRangeChanged.connect(self._update_y_range)
+        view.setMouseEnabled(x=True, y=False)
+
+        # Set right axis
+        right_axis = plot.getAxis('right')
+        right_axis.setWidth(60)
+        right_axis.setStyle(tickFont=AXIS_FONT)
+
+        # Connect x-axis link
+        if self._plots:
+            first_plot = list(self._plots.values())[0]
+            plot.setXLink(first_plot)
+
+        # Store plot object in dict
+        self._plots[plot_name] = plot
+
+    def add_item(
+        self,
+        item_class: Type[ChartItem],
+        item_name: str,
+        plot_name: str
+    ):
+        """
+        Add chart item.
+        """
+        item = item_class(self._manager)
+        self._items[item_name] = item
+
+        plot = self._plots.get(plot_name)
+        plot.addItem(item)
+        self._item_plot_map[item] = plot
+
+        self._layout.nextRow()
+        self._layout.addItem(plot)
+
+    def get_all_plots(self):
+        """
+        Get all plot objects.
+        """
+        return self._plots.values()
+
+    def clear_all(self) -> None:
+        """
+        Clear all data.
+        """
+        self._manager.clear_all()
+
+        for item in self._items.values():
+            item.clear_all()
+
+        if self._cursor:
+            self._cursor.clear_all()
+
+    def update_history(self, history: List[BarData]) -> None:
+        """
+        Update a list of bar data.
+        """
+        self._manager.update_history(history)
+
+        for item in self._items.values():
+            item.update_history(history)
+
+        self._update_plot_limits()
+
+        self.move_to_right()
+
+    def update_bar(self, bar: BarData) -> None:
+        """
+        Update single bar data.
+        """
+        self._manager.update_bar(bar)
+
+        for item in self._items.values():
+            item.update_bar(bar)
+
+        self._update_plot_limits()
+
+        if self._right_ix >= (self._manager.get_count() - self._bar_count / 2):
+            self.move_to_right()
+
+    def _update_plot_limits(self) -> None:
+        """
+        Update the limit of plots.
+        """
+        for item, plot in self._item_plot_map.items():
+            min_value, max_value = item.get_y_range()
+
+            plot.setLimits(
+                xMin=-1,
+                xMax=self._manager.get_count(),
+                yMin=min_value,
+                yMax=max_value
+            )
+
+    def _update_x_range(self) -> None:
+        """
+        Update the x-axis range of plots.
+        """
+        max_ix = self._right_ix
+        min_ix = self._right_ix - self._bar_count
+
+        for plot in self._plots.values():
+            plot.setRange(xRange=(min_ix, max_ix), padding=0)
+
+    def _update_y_range(self) -> None:
+        """
+        Update the y-axis range of plots.
+        """
+        view = self._first_plot.getViewBox()
+        view_range = view.viewRange()
+
+        min_ix = max(0, int(view_range[0][0]))
+        max_ix = min(self._manager.get_count(), int(view_range[0][1]))
+
+        # Update limit for y-axis
+        for item, plot in self._item_plot_map.items():
+            y_range = item.get_y_range(min_ix, max_ix)
+            plot.setRange(yRange=y_range)
+
+    def paintEvent(self, event: QtGui.QPaintEvent) -> None:
+        """
+        Reimplement this method of parent to update current max_ix value.
+        """
+        view = self._first_plot.getViewBox()
+        view_range = view.viewRange()
+        self._right_ix = max(0, view_range[0][1])
+
+        super().paintEvent(event)
+
+    def keyPressEvent(self, event: QtGui.QKeyEvent) -> None:
+        """
+        Reimplement this method of parent to move chart horizontally and zoom in/out.
+        """
+        if event.key() == QtCore.Qt.Key_Left:
+            self._on_key_left()
+        elif event.key() == QtCore.Qt.Key_Right:
+            self._on_key_right()
+        elif event.key() == QtCore.Qt.Key_Up:
+            self._on_key_up()
+        elif event.key() == QtCore.Qt.Key_Down:
+            self._on_key_down()
+
+    def wheelEvent(self, event: QtGui.QWheelEvent) -> None:
+        """
+        Reimplement this method of parent to zoom in/out.
+        """
+        delta = event.angleDelta()
+
+        if delta.y() > 0:
+            self._on_key_up()
+        elif delta.y() < 0:
+            self._on_key_down()
+
+    def _on_key_left(self) -> None:
+        """
+        Move chart to left.
+        """
+        self._right_ix -= 1
+        self._right_ix = max(self._right_ix, self._bar_count)
+
+        self._update_x_range()
+        self._cursor.move_left()
+        self._cursor.update_info()
+
+    def _on_key_right(self) -> None:
+        """
+        Move chart to right.
+        """
+        self._right_ix += 1
+        self._right_ix = min(self._right_ix, self._manager.get_count())
+
+        self._update_x_range()
+        self._cursor.move_right()
+        self._cursor.update_info()
+
+    def _on_key_down(self) -> None:
+        """
+        Zoom out the chart.
+        """
+        self._bar_count *= 1.2
+        self._bar_count = min(int(self._bar_count), self._manager.get_count())
+
+        self._update_x_range()
+        self._cursor.update_info()
+
+    def _on_key_up(self) -> None:
+        """
+        Zoom in the chart.
+        """
+        self._bar_count /= 1.2
+        self._bar_count = max(int(self._bar_count), self.MIN_BAR_COUNT)
+
+        self._update_x_range()
+        self._cursor.update_info()
+
+    def move_to_right(self) -> None:
+        """
+        Move chart to the most right.
+        """
+        self._right_ix = self._manager.get_count()
+        self._update_x_range()
+        self._cursor.update_info()
+
+
+class ChartCursor(QtCore.QObject):
+    """"""
+
+    def __init__(
+        self,
+        widget: ChartWidget,
+        manager: BarManager,
+        plots: Dict[str, pg.GraphicsObject]
+    ):
+        """"""
+        super().__init__()
+
+        self._widget: ChartWidget = widget
+        self._manager: BarManager = manager
+        self._plots: Dict[str, pg.GraphicsObject] = plots
+
+        self._x: int = 0
+        self._y: int = 0
+        self._plot_name: str = ""
+
+        self._init_ui()
+        self._connect_signal()
+
+    def _init_ui(self):
+        """"""
+        self._init_line()
+        self._init_label()
+        self._init_info()
+
+    def _init_line(self) -> None:
+        """
+        Create line objects.
+        """
+        self._v_lines: Dict[str, pg.InfiniteLine] = {}
+        self._h_lines: Dict[str, pg.InfiniteLine] = {}
+        self._views: Dict[str, pg.ViewBox] = {}
+
+        pen = pg.mkPen(WHITE_COLOR)
+
+        for plot_name, plot in self._plots.items():
+            v_line = pg.InfiniteLine(angle=90, movable=False, pen=pen)
+            h_line = pg.InfiniteLine(angle=0, movable=False, pen=pen)
+            view = plot.getViewBox()
+
+            for line in [v_line, h_line]:
+                line.setZValue(0)
+                line.hide()
+                view.addItem(line)
+
+            self._v_lines[plot_name] = v_line
+            self._h_lines[plot_name] = h_line
+            self._views[plot_name] = view
+
+    def _init_label(self) -> None:
+        """
+        Create label objects on axis.
+        """
+        self._y_labels: Dict[str, pg.TextItem] = {}
+        for plot_name, plot in self._plots.items():
+            label = pg.TextItem(plot_name, fill=CURSOR_COLOR, color=BLACK_COLOR)
+            label.hide()
+            label.setZValue(2)
+            plot.addItem(label, ignoreBounds=True)
+            self._y_labels[plot_name] = label
+
+        self._x_label: pg.TextItem = pg.TextItem(
+            "datetime", fill=CURSOR_COLOR, color=BLACK_COLOR)
+        self._x_label.hide()
+        self._x_label.setZValue(2)
+        plot.addItem(self._x_label, ignoreBounds=True)
+
+    def _init_info(self) -> None:
+        """
+        """
+        self._info = pg.TextItem("info", color=CURSOR_COLOR)
+        self._info.hide()
+        self._info.setZValue(2)
+
+        plot = list(self._plots.values())[0]
+        plot.addItem(self._info, ignoreBounds=True)
+
+    def _connect_signal(self) -> None:
+        """
+        Connect mouse move signal to update function.
+        """
+        self._proxy = pg.SignalProxy(
+            self._widget.scene().sigMouseMoved,
+            rateLimit=360,
+            slot=self._mouse_moved
+        )
+
+    def _mouse_moved(self, evt: tuple) -> None:
+        """
+        Callback function when mouse is moved.
+        """
+        if not self._manager.get_count():
+            return
+
+        # First get current mouse point
+        pos = evt[0]
+        for plot_name, view in self._views.items():
+            rect = view.sceneBoundingRect()
+
+            if rect.contains(pos):
+                mouse_point = view.mapSceneToView(pos)
+                self._x = to_int(mouse_point.x())
+                self._y = mouse_point.y()
+                self._plot_name = plot_name
+                break
+
+        # Then update cursor component
+        self._update_line()
+        self._update_label()
+        self.update_info()
+
+    def _update_line(self) -> None:
+        """"""
+        for v_line in self._v_lines.values():
+            v_line.setPos(self._x)
+            v_line.show()
+
+        for plot_name, h_line in self._h_lines.items():
+            if plot_name == self._plot_name:
+                h_line.setPos(self._y)
+                h_line.show()
+            else:
+                h_line.hide()
+
+    def _update_label(self) -> None:
+        """"""
+        bottom_plot = list(self._plots.values())[-1]
+        axis_width = bottom_plot.getAxis("right").width()
+        axis_height = bottom_plot.getAxis("bottom").height()
+        axis_offset = QtCore.QPointF(axis_width, axis_height)
+
+        bottom_view = list(self._views.values())[-1]
+        bottom_right = bottom_view.mapSceneToView(
+            bottom_view.sceneBoundingRect().bottomRight() - axis_offset
+        )
+
+        for plot_name, label in self._y_labels.items():
+            if plot_name == self._plot_name:
+                label.setText(str(self._y))
+                label.show()
+                label.setPos(bottom_right.x(), self._y)
+            else:
+                label.hide()
+
+        dt = self._manager.get_datetime(self._x)
+        if dt:
+            self._x_label.setText(dt.strftime("%Y-%m-%d %H:%M:%S"))
+            self._x_label.show()
+            self._x_label.setPos(self._x, bottom_right.y())
+            self._x_label.setAnchor((0, 0))
+
+    def update_info(self) -> None:
+        """"""
+        bar = self._manager.get_bar(self._x)
+
+        if bar:
+            op = bar.open_price
+            hp = bar.high_price
+            lp = bar.low_price
+            cp = bar.close_price
+            v = bar.volume
+            text = f"(open){op}  (high){hp}  (low){lp}  (close){cp}  (volume){v}"
+        else:
+            text = ""
+
+        self._info.setText(text)
+        self._info.show()
+
+        view = list(self._views.values())[0]
+        top_left = view.mapSceneToView(view.sceneBoundingRect().topLeft())
+        self._info.setPos(top_left)
+
+    def move_right(self) -> None:
+        """
+        Move cursor index to right by 1.
+        """
+        if self._x == self._manager.get_count() - 1:
+            return
+        self._x += 1
+
+        self._update_after_move()
+
+    def move_left(self) -> None:
+        """
+        Move cursor index to left by 1.
+        """
+        if self._x == 0:
+            return
+        self._x -= 1
+
+        self._update_after_move()
+
+    def _update_after_move(self) -> None:
+        """
+        Update cursor after moved by left/right.
+        """
+        bar = self._manager.get_bar(self._x)
+        self._y = bar.close_price
+
+        self._update_line()
+        self._update_label()
+
+    def clear_all(self) -> None:
+        """
+        Clear all data.
+        """
+        self._x = 0
+        self._y = 0
+        self._plot_name = ""
+
+        for line in self._v_lines + self._h_lines:
+            line.hide()
+
+        for label in self._y_labels + [self._x_label]:
+            label.hide()
diff --git a/vnpy/trader/utility.py b/vnpy/trader/utility.py
index a154e175..88c1e105 100644
--- a/vnpy/trader/utility.py
+++ b/vnpy/trader/utility.py
@@ -22,6 +22,9 @@ def extract_vt_symbol(vt_symbol: str):
 
 
 def generate_vt_symbol(symbol: str, exchange: Exchange):
+    """
+    return vt_symbol
+    """
     return f"{symbol}.{exchange.value}"