Add one more point to the end of a ListStepPlot...

like WMA does
Mathics3 · Sep 27, 2024 · 394e2e2 · 394e2e2
1 parent 1d063a8
commit 394e2e2
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Showing 2 changed files with 15 additions and 8 deletions.
diff --git a/mathics/builtin/drawing/plot.py b/mathics/builtin/drawing/plot.py
@@ -2067,14 +2067,16 @@ class ListStepPlot(_ListPlot):
     >> ListStepPlot[{1, 1, 2, 3, 5, 8, 13, 21}]
      = -Graphics-
 
-
-    By default ListStepPlots are joined, but that can be disabled.
+    'ListPlot' accepts a superset of the Graphics options. \
+    By default, 'ListStepPlot's are joined, but that can be disabled.
 
     >> ListStepPlot[{1, 1, 2, 3, 5, 8, 13, 21}, Joined->False]
      = -Graphics-
-    ListPlot accepts a superset of the Graphics options.
 
-    >> ListStepPlot[{{-2, -1}, {-1, -1}, {1, 3}}, Filling->Axis]
+    The same as the first example but using a list of point as data, \
+    and filling the plot to the x axis.
+
+    >> ListStepPlot[{{1, 1}, {3, 2}, {4, 5}, {5, 8}, {6, 13}, {7, 21}}, Filling->Axis]
      = -Graphics-
     """
 

diff --git a/mathics/eval/drawing/plot.py b/mathics/eval/drawing/plot.py
@@ -250,11 +250,13 @@ def eval_ListPlot(
                     break
                 pass
 
-            # For step plots, we have 2n - 1 points These
-            # we create from the n points here.
-            # We insert a new point from the y coordinate
+            # For step plots, we have 2n points; n -1 of these
+            # we create from the n points by
+            # insert a new point from the y coordinate
             # of the previous point in between each new point
-            # other than the first point
+            # other than the first point. The last plot point
+            # has the preview plot point y value and the average
+            # step value added to the last x value
             if list_plot_type == ListPlotType.ListStepPlot:
                 step_plot_group = []
                 last_point = seg[0]
@@ -264,6 +266,9 @@ def eval_ListPlot(
                         step_plot_group.append(point)
                     step_plot_group.append(point)
                     last_point = point
+                last_x = last_point[0]
+                average = last_x + ((seg[0][0] + last_x) / 2)
+                step_plot_group.append((average, last_point[1]))
                 plot_groups[lidx][i] = step_plot_group
 
             i += 1