From ae7f9735a5c863a6209c8d09c385e20b83103c51 Mon Sep 17 00:00:00 2001
From: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
Date: Tue, 11 Jan 2022 19:12:44 +0100
Subject: [PATCH] Backport PR #22053: DOC: Document default cap styles

---
 lib/matplotlib/_enums.py  | 4 +++-
 lib/matplotlib/lines.py   | 4 ++++
 lib/matplotlib/patches.py | 3 +++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/_enums.py b/lib/matplotlib/_enums.py
index 3e4393e7979d..28650dd369d9 100644
--- a/lib/matplotlib/_enums.py
+++ b/lib/matplotlib/_enums.py
@@ -128,6 +128,9 @@ class CapStyle(str, _AutoStringNameEnum):
     For a visual impression of each *CapStyle*, `view these docs online
     <CapStyle>` or run `CapStyle.demo`.
 
+    By default, `~.backend_bases.GraphicsContextBase` draws a stroked line as
+    squared off at its endpoints.
+
     **Supported values:**
 
     .. rst-class:: value-list
@@ -168,7 +171,6 @@ def demo():
             ax.plot(xx, yy, lw=12, color='tab:blue', solid_capstyle=style)
             ax.plot(xx, yy, lw=1, color='black')
             ax.plot(xx, yy, 'o', color='tab:red', markersize=3)
-        ax.text(2.25, 0.55, '(default)', ha='center')
 
         ax.set_ylim(-.5, 1.5)
         ax.set_axis_off()
diff --git a/lib/matplotlib/lines.py b/lib/matplotlib/lines.py
index 273a93c0b86f..1014c497d9c5 100644
--- a/lib/matplotlib/lines.py
+++ b/lib/matplotlib/lines.py
@@ -1337,6 +1337,8 @@ def set_dash_capstyle(self, s):
         """
         How to draw the end caps if the line is `~Line2D.is_dashed`.
 
+        The default capstyle is :rc:`lines.dash_capstyle`.
+
         Parameters
         ----------
         s : `.CapStyle` or %(CapStyle)s
@@ -1351,6 +1353,8 @@ def set_solid_capstyle(self, s):
         """
         How to draw the end caps if the line is solid (not `~Line2D.is_dashed`)
 
+        The default capstyle is :rc:`lines.solid_capstyle`.
+
         Parameters
         ----------
         s : `.CapStyle` or %(CapStyle)s
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
index 253e8abe2ef7..adcf2a1b1a77 100644
--- a/lib/matplotlib/patches.py
+++ b/lib/matplotlib/patches.py
@@ -479,6 +479,9 @@ def set_capstyle(self, s):
         """
         Set the `.CapStyle`.
 
+        The default capstyle is 'round' for `.FancyArrowPatch` and 'butt' for
+        all other patches.
+
         Parameters
         ----------
         s : `.CapStyle` or %(CapStyle)s