Improve ps handling of individual usetex strings.

anntzer · anntzer · commit 6cb9d626d87f · 2020-04-28T21:01:59.000+02:00
The ps backend currently determines usetex status solely based on the
rcparam at renderer instantiation time; in particular, having single
Text objects with usetex=True in an otherwise usetex=False renderer
currently results in an AttributeError.  Instead, detect that and do a
best-effort fix which is to try rendering with mathtext instead of
usetex.

(Actually fixing the ps backend would be nicer, but a bit of work.)

Also fix another ps test to not use a temporary directory.
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
@@ -469,6 +469,14 @@ def draw_path_collection(self, gc, master_transform, paths, all_transforms,
 
     def draw_tex(self, gc, x, y, s, prop, angle, ismath='TeX!', mtext=None):
         # docstring inherited
+        if not hasattr(self, "psfrag"):
+            _log.warning(
+                "The PS backend determines usetex status solely based on "
+                "rcParams['text.usetex'] and does not support having "
+                "usetex=True only for some elements; this element will thus "
+                "be rendered as if usetex=False.")
+            self.draw_text(gc, x, y, s, prop, angle, ismath, mtext)
+            return
 
         w, h, bl = self.get_text_width_height_descent(s, prop, ismath)
         fontsize = prop.get_size_in_points()
diff --git a/lib/matplotlib/tests/test_backend_ps.py b/lib/matplotlib/tests/test_backend_ps.py
@@ -117,10 +117,19 @@ def test_transparency():
 
 
 @needs_usetex
-def test_failing_latex(tmpdir):
+def test_failing_latex():
     """Test failing latex subprocess call"""
     mpl.rcParams['text.usetex'] = True
     # This fails with "Double subscript"
     plt.xlabel("$22_2_2$")
     with pytest.raises(RuntimeError):
-        plt.savefig(Path(tmpdir, "tmpoutput.ps"))
+        plt.savefig(io.BytesIO(), format="ps")
+
+
+@needs_usetex
+def test_partial_usetex(caplog):
+    caplog.set_level("WARNING")
+    plt.figtext(.5, .5, "foo", usetex=True)
+    plt.savefig(io.BytesIO(), format="ps")
+    assert caplog.records and all("as if usetex=False" in record.getMessage()
+                                  for record in caplog.records)
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -726,7 +726,7 @@ def draw(self, renderer):
                 if textobj.get_usetex():
                     textrenderer.draw_tex(gc, x, y, clean_line,
                                           textobj._fontproperties, angle,
-                                          mtext=mtext)
+                                          ismath=ismath, mtext=mtext)
                 else:
                     textrenderer.draw_text(gc, x, y, clean_line,
                                            textobj._fontproperties, angle,
