From ee043fce0ee30ec4108cd9f14f0566448306aa3e Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Thu, 4 Jan 2018 13:11:41 -0800
Subject: [PATCH] Hide fully transparent text in PS output.

PS doesn't really support transparency (because the format itself
doesn't, unless using some nonstandard extensions), but has some special
casing for "fully transparent" (see e.g. "rgbFace is None" check in
_draw_ps).

Also implement the special-casing for text.
---
 lib/matplotlib/backends/backend_ps.py            |   5 ++++-
 .../baseline_images/test_backend_ps/empty.pdf    | Bin 0 -> 1253 bytes
 lib/matplotlib/tests/test_backend_ps.py          |   9 +++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 lib/matplotlib/tests/baseline_images/test_backend_ps/empty.pdf

diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 8c247677704a..c2dc1d02463a 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -631,13 +631,16 @@ def draw_tex(self, gc, x, y, s, prop, angle, ismath='TeX!', mtext=None):
 
     def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
         """
-        draw a Text instance
+        Draw a Text instance.
         """
         # local to avoid repeated attribute lookups
         write = self._pswriter.write
         if debugPS:
             write("% text\n")
 
+        if len(gc.get_rgb()) == 4 and gc.get_rgb()[3] == 0:
+            return  # Special handling for fully transparent.
+
         if ismath=='TeX':
             return self.draw_tex(gc, x, y, s, prop, angle)
 
diff --git a/lib/matplotlib/tests/baseline_images/test_backend_ps/empty.pdf b/lib/matplotlib/tests/baseline_images/test_backend_ps/empty.pdf
new file mode 100644
index 0000000000000000000000000000000000000000..80a7f0b2fe39532f274fa6f54cf117fe690464fa
GIT binary patch
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diff --git a/lib/matplotlib/tests/test_backend_ps.py b/lib/matplotlib/tests/test_backend_ps.py
index fcac2539424c..0d86b32bd9b7 100644
--- a/lib/matplotlib/tests/test_backend_ps.py
+++ b/lib/matplotlib/tests/test_backend_ps.py
@@ -12,6 +12,7 @@
 import matplotlib
 import matplotlib.pyplot as plt
 from matplotlib import patheffects
+from matplotlib.testing.decorators import image_comparison
 from matplotlib.testing.determinism import (_determinism_source_date_epoch,
                                             _determinism_check)
 
@@ -148,3 +149,11 @@ def test_determinism_all():
 def test_determinism_all_tex():
     """Test for reproducible PS/tex output"""
     _determinism_check(format="ps", usetex=True)
+
+
+@image_comparison(baseline_images=["empty"], extensions=["eps"])
+def test_transparency():
+    fig, ax = plt.subplots()
+    ax.set_axis_off()
+    ax.plot([0, 1], color="r", alpha=0)
+    ax.text(.5, .5, "foo", color="r", alpha=0)