Adding plot_group argument to indicator constructor

kernc · Feb 12, 2025 · b7018eb · b7018eb
1 parent 915bd09
commit b7018eb
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Showing 2 changed files with 16 additions and 3 deletions.
diff --git a/backtesting/_plotting.py b/backtesting/_plotting.py
@@ -527,6 +527,7 @@ def __eq__(self, other):
 
         ohlc_colors = colorgen()
         indicator_figs = []
+        plot_group_to_fig = {}
 
         for i, value in enumerate(indicators):
             value = np.atleast_2d(value)
@@ -541,8 +542,14 @@ def __eq__(self, other):
             if is_overlay:
                 fig = fig_ohlc
             else:
-                fig = new_indicator_figure()
-                indicator_figs.append(fig)
+                if (value._opts['plot_group'] is not None and
+                    value._opts['plot_group'] in plot_group_to_fig):
+                    fig = plot_group_to_fig[value._opts['plot_group']]
+                else:
+                    fig = new_indicator_figure()
+                    indicator_figs.append(fig)
+                    if value._opts['plot_group'] is not None:
+                        plot_group_to_fig[value._opts['plot_group']] = fig
             tooltips = []
             colors = value._opts['color']
             colors = colors and cycle(_as_list(colors)) or (

diff --git a/backtesting/backtesting.py b/backtesting/backtesting.py
@@ -79,6 +79,7 @@ def _check_params(self, params):
     def I(self,  # noqa: E743
           func: Callable, *args,
           name=None, plot=True, overlay=None, color=None, scatter=False,
+          plot_group=None,
           **kwargs) -> np.ndarray:
         """
         Declare an indicator. An indicator is just an array of values
@@ -105,6 +106,11 @@ def I(self,  # noqa: E743
         candlestick chart. By default, a heuristic is used which decides
         correctly most of the time.
 
+        For non-overlaying indicators, if `plot_group` is set,
+        indicators with the same `plot_group` value will be combined
+        on one chart which is useful for displaying crossing indicators
+        like Aroon.
+
         `color` can be string hex RGB triplet or X11 color name.
         By default, the next available color is assigned.
 
@@ -179,7 +185,7 @@ def _format_name(name: str) -> str:
         value = _Indicator(value, name=name, plot=plot, overlay=overlay,
                            color=color, scatter=scatter,
                            # _Indicator.s Series accessor uses this:
-                           index=self.data.index)
+                           index=self.data.index, plot_group=plot_group)
         self._indicators.append(value)
         return value