Legend ntuples (#33)

* replace legend dict with list of namedtuples

* updated test to work with lst of LegendItem tuples

src/shellplot/_plotting.py

@@ -8,6 +8,7 @@
 
 import numpy as np
 
+from shellplot.drawing import LegendItem
 from shellplot.utils import numpy_1d, numpy_2d
 
 
@@ -73,7 +74,7 @@ def _plot(fig, x, y, marker=True, line=None, label=None, **kwargs):
 
     if label is not None:
         key = marker or line
-        fig.legend.update({key: label})
+        fig.legend.append(LegendItem(symbol=key, name=label))
 
 
 def _within_display(x, y):

src/shellplot/drawing.py

@@ -4,6 +4,7 @@
 converts them to strings. Please note that drawing is entirely agnostic to the
 type of plot.
 """
+from collections import namedtuple
 from typing import List
 
 PALETTE = {
@@ -26,6 +27,8 @@
     23: "┐",
 }
 
+LegendItem = namedtuple("LegendItem", ["symbol", "name"])
+
 
 def draw(canvas, x_axis, y_axis, legend=None) -> str:
     """Draw figure from plot elements (i.e. canvas, x-axis, y-axis, legend)
@@ -132,8 +135,8 @@ def _draw_x_axis(x_axis, left_pad) -> List[str]:
 def _draw_legend(legend) -> List[str]:
     legend_lines = list()
 
-    for marker, name in legend.items():
-        legend_str = f"{PALETTE[marker]} {name}"
+    for item in legend:
+        legend_str = f"{PALETTE[item.symbol]} {item.name}"
         legend_lines.append(legend_str)
     return legend_lines
 

src/shellplot/figure.py

@@ -67,7 +67,7 @@ def clear(self):
 
     def _init_figure_elements(self):
         self.canvas = np.zeros(shape=(self.figsize[0], self.figsize[1]), dtype=int)
-        self.legend = dict()
+        self.legend = list()
         self.markers = cycle([1, 2, 3, 4, 5, 6])
         self.lines = cycle([10, 11])
 

tests/test_drawing.py

@@ -6,6 +6,7 @@
 
 from shellplot.axis import Axis
 from shellplot.drawing import (
+    LegendItem,
     _draw_canvas,
     _draw_legend,
     _draw_x_axis,
@@ -15,7 +16,7 @@
 
 
 def test_draw_legend():
-    legend = {1: "one", 2: "two"}
+    legend = [LegendItem(1, "one"), LegendItem(2, "two")]
     legend_lines = ["+ one", "* two"]
     assert legend_lines == _draw_legend(legend)