...

pyproject.toml

@@ -20,7 +20,7 @@ classifiers = [
 ]
 
 [project.optional-dependencies]
-dev = ["yfinance", "pytest", "ipykernel", "ta-lib", "ruff"]
+extras = ["yfinance", "pytest", "ipykernel", "ta-lib", "ruff"]
 
 [tool.hatch.version]
 path = "src/mplchart/__init__.py"

src/mplchart/chart.py

@@ -105,7 +105,7 @@ def valid_target(target):
         """whether the target bname is valid"""
         return target in ("main", "samex", "twinx", "above", "below")
 
-    def inspect_data(self, data):
+    def init_mapper(self, data):
         """initalizes chart from data"""
 
         if self.source_data is None:
@@ -114,28 +114,48 @@ def inspect_data(self, data):
         if not self.mapper_done:
             self.config_mapper(data=data)
 
+    def config_mapper(self, *, data=None):
+        """Configures the date mapper from the original data"""
+
+        self.mapper_done = True
+
+        if self.use_calendar:
+            self.mapper = RawDateMapper(
+                index=data.index, start=self.start, end=self.end, max_bars=self.max_bars
+            )
+        elif data is not None:
+            self.mapper = DateIndexMapper(
+                index=data.index, start=self.start, end=self.end, max_bars=self.max_bars
+            )
+        else:
+            raise ValueError("Cannot create mapper. data is None!")
+
+        if self.mapper:
+            ax = self.root_axes()
+            self.mapper.config_axes(ax)
+
     def rebase_data(self, data):
         if self.source_data is None:
             warnings.warn("No source data to rebase to!")
             return data
 
-        source_data = self.mapper.slice(self.source_data)
-        index = data.index.intersection(source_data.index)
+        source_data = self.mapper.extract_df(self.source_data)
+        mapped_data = self.mapper.extract_df(data)
 
-        if not len(index):
+        if not len(data) or not len(source_data):
             warnings.warn("No intersection of data!")
             return data
 
-        dp = data.loc[index[0]]
-        sp = source_data.loc[index[0]]
-        factor = sp / dp
+        sp = source_data.loc[0].close
+        mp = mapped_data.loc[0].close
+        factor = sp / mp
 
         return data.filter(["open", "high", "low", "close"]) * factor
 
     def extract_df(self, data):
         """extract dataframe subset"""
 
-        self.inspect_data(data)
+        self.init_mapper(data)
 
         if self.mapper:
             return self.mapper.extract_df(data)
@@ -164,26 +184,6 @@ def set_title(self, title):
         ax = self.root_axes()
         ax.set_title(title)
 
-    def config_mapper(self, *, data=None):
-        """Configures the date mapper from the original data"""
-
-        self.mapper_done = True
-
-        if self.use_calendar:
-            self.mapper = RawDateMapper(
-                index=data.index, start=self.start, end=self.end, max_bars=self.max_bars
-            )
-        elif data is not None:
-            self.mapper = DateIndexMapper(
-                index=data.index, start=self.start, end=self.end, max_bars=self.max_bars
-            )
-        else:
-            raise ValueError("Cannot create mapper. data is None!")
-
-        if self.mapper:
-            ax = self.root_axes()
-            self.mapper.config_axes(ax)
-
     def config_axes(self, ax, root=False):
         """configures axes"""
 

src/mplchart/mapper.py

@@ -1,4 +1,4 @@
-""" date mapper """
+"""date mapper"""
 
 import numpy as np
 import pandas as pd
@@ -7,56 +7,29 @@
 from .formatter import DateIndexFormatter
 
 
-def get_boundaries(index, max_bars=None, start=None, end=None):
-    if index is None:
-        raise ValueError("Index is None!")
-
-    if max_bars and (start or end):
-        raise ValueError(
-            "Cannot specify `max_bars` together with `start` or `end`!"
-        )
-
-    if start and end and start >= end:
-        raise ValueError("Argument `start` value must be less than `end` value!")
-
-    if max_bars and len(index) > max_bars:
-        start = index[-max_bars]
-
-    if start is None and len(index):
-        start = index[0]
-
-    if end is None and len(index):
-        end = index[-1]
-
-    return start, end
-
-
 class RawDateMapper:
     """RawDate mapper between date and number using matplotlib.dates"""
 
     def __init__(self, index, max_bars=None, start=None, end=None):
-        start, end = get_boundaries(index, max_bars=max_bars, start=start, end=end)
+        if start or end:
+            locs = index.slice_indexer(start=start, end=end)
+            index = index[locs]
+
+        if max_bars > 0:
+            index = index[-max_bars:]
 
-        self.start = start
-        self.end = end
+        self.start = index[0]
+        self.end = index[-1]
 
     def map_date(self, date):  # needed for plot_vline
         """returns date as number/coordinate"""
         return date
 
-    def slice(self, data):
-        """slice data on dates"""
-
-        if self.start or self.end:
-            data = data.loc[self.start: self.end]
-
-        return data
-
     def extract_df(self, data):
         """extracts dataframe by mapping date to number/coordinate"""
 
         if self.start or self.end:
-            data = data.loc[self.start: self.end]
+            data = data.loc[self.start:self.end]
 
         return data
 
@@ -73,15 +46,19 @@ def config_axes(self, ax):
         pass
 
 
+
 class DateIndexMapper:
     """DateIndex mapper between date and position/coordinate"""
 
     def __init__(self, index, *, max_bars=None, start=None, end=None):
-        start, end = get_boundaries(index, max_bars=max_bars, start=start, end=end)
+        if start or end:
+            locs = index.slice_indexer(start=start, end=end)
+            index = index[locs]
+
+        if max_bars > 0:
+            index = index[-max_bars:]
 
         self.index = index
-        self.start = start
-        self.end = end
 
     def map_date(self, date):  # nedded for plot_vline
         """location of date in index"""
@@ -90,22 +67,11 @@ def map_date(self, date):  # nedded for plot_vline
 
         return result[0]
 
-    def slice(self, data):
-        """slice data on dates"""
-
-        if self.start or self.end:
-            data = data.loc[self.start: self.end]
-
-        return data
-
     def extract_df(self, data):
         """extracts dataframe by mapping date to position/coordinate"""
 
         xloc = pd.Series(np.arange(len(self.index)), index=self.index)
 
-        if self.start or self.end:
-            xloc = xloc[self.start: self.end]
-
         xloc, data = xloc.align(data, join="inner")
 
         return data.set_axis(xloc)

tasks.py

@@ -7,6 +7,12 @@
 FOLDER = Path(__file__).parent
 
 
+@task
+def install(c):
+    """Check package versions"""
+    c.run("pip install -e \".[extras]\"")
+
+
 @task
 def info(c):
     """Check package versions"""