New Feature: ChartAsync

- Added the ChartAsync class, allowing for more sophisticated Charts and SubCharts.
- Symbol searching, timeframe selectors, and more is now possible with this varation of Chart.

`QtChart` and `WxChart` have access to all the methods that `ChartAsync` has, however they utilize their own respective event loops rather than asyncio.

New Feature: `StreamlitChart`
- Chart window that can display static data within a Streamlit application.

Removed the `subscribe_click` method.

examples/6_async/async.py

@@ -0,0 +1,56 @@
+import asyncio
+import pandas as pd
+
+from lightweight_charts import ChartAsync
+
+
+def get_bar_data(symbol, timeframe):
+    return pd.read_csv(f'bar_data/{symbol}_{timeframe}.csv')
+
+
+class API:
+    def __init__(self):
+        self.chart = None  # Changes after each callback.
+        self.symbol = 'TSLA'
+        self.timeframe = '5min'
+
+    async def on_search(self, searched_string):  # Called when the user searches.
+        self.symbol = searched_string
+        new_data = await self.get_data()
+        if new_data.empty:
+            return
+        self.chart.set(new_data)
+        self.chart.corner_text(searched_string)
+
+    async def on_timeframe_selection(self, timeframe):  # Called when the user changes the timeframe.
+        self.timeframe = timeframe
+        new_data = await self.get_data()
+        if new_data.empty:
+            return
+        self.chart.set(new_data)
+
+    async def get_data(self):
+        if self.symbol not in ('AAPL', 'GOOGL', 'TSLA'):
+            print(f'No data for "{self.symbol}"')
+            return pd.DataFrame()
+        data = get_bar_data(self.symbol, self.timeframe)
+        return data
+
+
+async def main():
+    api = API()
+
+    chart = ChartAsync(api=api, debug=True)
+    chart.legend(True)
+
+    chart.create_switcher(api.on_timeframe_selection, '1min', '5min', '30min', default='5min')
+    chart.corner_text(api.symbol)
+
+    df = get_bar_data(api.symbol, api.timeframe)
+    chart.set(df)
+
+    await chart.show(block=True)
+
+
+if __name__ == '__main__':
+    asyncio.run(main())

examples/6_callbacks/callbacks.py

@@ -1,18 +0,0 @@
-import pandas as pd
-from lightweight_charts import Chart
-
-
-def on_click(bar: dict):
-    print(f"Time: {bar['time']} | Close: {bar['close']}")
-
-
-if __name__ == '__main__':
-
-    chart = Chart()
-
-    df = pd.read_csv('ohlcv.csv')
-    chart.set(df)
-
-    chart.subscribe_click(on_click)
-
-    chart.show(block=True)