Polygon:

- Added async methods to polygon.
- The `requests` library is no longer required, with `urllib` being used instead.
- Added the `get_bar_data` function, which returns a dataframe of aggregate data from polygon.
- Opened up the `subscribe` and `unsubscribe` functions

Enhancements:
- Tables will now scroll when the rows exceed table height.

Bugs:
- Fixed a bug preventing async functions being used with horizontal line event.
- Fixed a bug causing the legend to show duplicate lines if the line was created after the legend.
- Fixed a bug causing the line hide icon to persist within the legend after deletion (#75)
- Fixed a bug causing the search box to be unfocused when the chart is loaded.

lightweight_charts/topbar.py

@@ -0,0 +1,90 @@
+import asyncio
+from typing import Dict
+
+from .util import jbool, Pane
+
+
+class Widget(Pane):
+    def __init__(self, topbar, value, func=None):
+        super().__init__(topbar.win)
+        self.value = value
+
+        def wrapper(v):
+            self.value = v
+            func(topbar._chart)
+
+        async def async_wrapper(v):
+            self.value = v
+            await func(topbar._chart)
+
+        self.win.handlers[self.id] = async_wrapper if asyncio.iscoroutinefunction(func) else wrapper
+
+
+class TextWidget(Widget):
+    def __init__(self, topbar, initial_text):
+        super().__init__(topbar, value=initial_text)
+        self.run_script(f'{self.id} = {topbar.id}.makeTextBoxWidget("{initial_text}")')
+
+    def set(self, string):
+        self.value = string
+        self.run_script(f'{self.id}.innerText = "{string}"')
+
+
+class SwitcherWidget(Widget):
+    def __init__(self, topbar, options, default, func):
+        super().__init__(topbar, value=default, func=func)
+        self.run_script(f'{self.id} = {topbar.id}.makeSwitcher({list(options)}, "{default}", "{self.id}")')
+
+
+class ButtonWidget(Widget):
+    def __init__(self, topbar, button, separator, func):
+        super().__init__(topbar, value=button, func=func)
+        self.run_script(f'{self.id} = {topbar.id}.makeButton("{button}", "{self.id}", {jbool(separator)})')
+
+    def set(self, string):
+        self.value = string
+        self.run_script(f'{self.id}.elem.innerText = "{string}"')
+
+
+class TopBar(Pane):
+    def __init__(self, chart):
+        super().__init__(chart.win)
+        self._chart = chart
+        self._widgets: Dict[str, Widget] = {}
+
+        self.click_bg_color = '#50565E'
+        self.hover_bg_color = '#3c434c'
+        self.active_bg_color = 'rgba(0, 122, 255, 0.7)'
+        self.active_text_color = '#ececed'
+        self.text_color = '#d8d9db'
+        self._created = False
+
+    def _create(self):
+        if self._created:
+            return
+        from lightweight_charts.abstract import JS
+        self._created = True
+        self.run_script(JS['callback'])
+        self.run_script(f'''
+        {self.id} = new TopBar( {self._chart.id}, '{self.hover_bg_color}', '{self.click_bg_color}',
+                                '{self.active_bg_color}', '{self.text_color}', '{self.active_text_color}')
+        ''')
+
+    def __getitem__(self, item):
+        if widget := self._widgets.get(item):
+            return widget
+        raise KeyError(f'Topbar widget "{item}" not found.')
+
+    def get(self, widget_name): return self._widgets.get(widget_name)
+
+    def switcher(self, name, options: tuple, default: str = None, func: callable = None):
+        self._create()
+        self._widgets[name] = SwitcherWidget(self, options, default if default else options[0], func)
+
+    def textbox(self, name: str, initial_text: str = ''):
+        self._create()
+        self._widgets[name] = TextWidget(self, initial_text)
+
+    def button(self, name, button_text: str, separator: bool = True, func: callable = None):
+        self._create()
+        self._widgets[name] = ButtonWidget(self, button_text, separator, func)