Merge pull request #360 from harenbrs/master

Support paths with datetime x-axis (#328)

Author: nschloe

test/test_datetime_paths.py

@@ -0,0 +1,33 @@
+import datetime as date
+
+import matplotlib.pyplot as plt
+from matplotlib import dates
+
+from helpers import assert_equality
+
+
+def plot():
+    fig = plt.figure()
+
+    times = [date.datetime(2020, 1, 1, 12, 00), date.datetime(2020, 1, 2, 12, 00)]
+    line = [2, 2]
+    upper = [3, 4]
+    lower = [1, 0]
+
+    plt.plot(times, line)
+    plt.fill_between(times, lower, upper)
+    ax = plt.gca()
+    ax.fmt_xdata = dates.DateFormatter("%d %b %Y %H:%M:%S")
+
+    return fig
+
+
+def test():
+    assert_equality(plot, __file__[:-3] + "_reference.tex")
+    return
+
+
+if __name__ == "__main__":
+    import helpers
+
+    helpers.compare_mpl_latex(plot)

test/test_datetime_paths_reference.tex

@@ -0,0 +1,32 @@
+\begin{tikzpicture}
+
+\definecolor{color0}{rgb}{0.12156862745098,0.466666666666667,0.705882352941177}
+
+\begin{axis}[
+date coordinates in=x,
+tick align=outside,
+tick pos=left,
+x grid style={white!69.01960784313725!black},
+xmin=2020-01-01 10:48, xmax=2020-01-02 13:12,
+xtick style={color=black},
+y grid style={white!69.01960784313725!black},
+ymin=-0.2, ymax=4.2,
+ytick style={color=black}
+]
+\path [fill=color0]
+(axis cs:2020-01-01 12:00:00+00:00,3)
+--(axis cs:2020-01-01 12:00:00+00:00,1)
+--(axis cs:2020-01-02 12:00:00+00:00,0)
+--(axis cs:2020-01-02 12:00:00+00:00,4)
+--(axis cs:2020-01-02 12:00:00+00:00,4)
+--(axis cs:2020-01-01 12:00:00+00:00,3)
+--cycle;
+
+\addplot [semithick, color0]
+table [header=false,col sep=comma] {%
+2020-01-01 12:00,2
+2020-01-02 12:00,2
+};
+\end{axis}
+
+\end{tikzpicture}

tikzplotlib/_path.py

@@ -1,6 +1,7 @@
 import matplotlib as mpl
 import numpy
 from matplotlib.markers import MarkerStyle
+from matplotlib.dates import num2date, DateConverter
 
 from . import _color
 from ._axes import _mpl_cmap2pgf_cmap
@@ -22,8 +23,10 @@ def draw_path(data, path, draw_options=None, simplify=None):
     ):
         return data, "", None, False
 
+    x_is_date = isinstance(data["current mpl axes obj"].xaxis.converter, DateConverter)
     nodes = []
     ff = data["float format"]
+    xformat = "{}" if x_is_date else ff
     prev = None
     for vert, code in path.iter_segments(simplify=simplify):
         # nschloe, Oct 2, 2015:
@@ -38,9 +41,13 @@ def draw_path(data, path, draw_options=None, simplify=None):
         # if code == mpl.path.Path.STOP: pass
         is_area = False
         if code == mpl.path.Path.MOVETO:
-            nodes.append(("(axis cs:" + ff + "," + ff + ")").format(*vert))
+            if x_is_date:
+                vert = [num2date(vert[0]), vert[1]]
+            nodes.append(("(axis cs:" + xformat + "," + ff + ")").format(*vert))
         elif code == mpl.path.Path.LINETO:
-            nodes.append(("--(axis cs:" + ff + "," + ff + ")").format(*vert))
+            if x_is_date:
+                vert = [num2date(vert[0]), vert[1]]
+            nodes.append(("--(axis cs:" + xformat + "," + ff + ")").format(*vert))
         elif code == mpl.path.Path.CURVE3:
             # Quadratic Bezier curves aren't natively supported in TikZ, but
             # can be emulated as cubic Beziers.
@@ -63,41 +70,54 @@ def draw_path(data, path, draw_options=None, simplify=None):
             Q1 = 1.0 / 3.0 * prev + 2.0 / 3.0 * vert[0:2]
             Q2 = 2.0 / 3.0 * vert[0:2] + 1.0 / 3.0 * vert[2:4]
             Q3 = vert[2:4]
+            if x_is_date:
+                Q1 = [num2date(Q1[0]), Q1[1]]
+                Q2 = [num2date(Q2[0]), Q2[1]]
+                Q3 = [num2date(Q3[0]), Q3[1]]
             nodes.append(
                 (
                     ".. controls (axis cs:"
-                    + ff
+                    + xformat
                     + ","
                     + ff
                     + ") "
                     + "and (axis cs:"
-                    + ff
+                    + xformat
                     + ","
                     + ff
                     + ") "
                     + ".. (axis cs:"
-                    + ff
+                    + xformat
                     + ","
                     + ff
                     + ")"
                 ).format(Q1[0], Q1[1], Q2[0], Q2[1], Q3[0], Q3[1])
             )
         elif code == mpl.path.Path.CURVE4:
             # Cubic Bezier curves.
+            if x_is_date:
+                vert = [
+                    num2date(vert[0]),
+                    vert[1],
+                    num2date(vert[2]),
+                    vert[3],
+                    num2date(vert[4]),
+                    vert[5],
+                ]
             nodes.append(
                 (
                     ".. controls (axis cs:"
-                    + ff
+                    + xformat
                     + ","
                     + ff
                     + ") "
                     + "and (axis cs:"
-                    + ff
+                    + xformat
                     + ","
                     + ff
                     + ") "
                     + ".. (axis cs:"
-                    + ff
+                    + xformat
                     + ","
                     + ff
                     + ")"