From 6cdf265b7c5ed27137b70cc1cd544d7194f80831 Mon Sep 17 00:00:00 2001
From: genrichez <2.2434764e+07+genrichez@users.noreply.github.com>
Date: Thu, 16 Jul 2026 21:52:32 +0000
Subject: [PATCH 1/3] fix: handle 3-digit shorthand hex in hex_to_rgb

Expand 3-char hex codes (e.g. #FFF) to 6-char before parsing.
Fixes both _plotly_utils and matplotlylib copies.

Closes #5661
---
 _plotly_utils/colors/__init__.py                         | 2 ++
 plotly/matplotlylib/mpltools.py                          | 2 ++
 tests/test_plotly_utils/colors/test_color_conversions.py | 9 +++++++++
 3 files changed, 13 insertions(+)

diff --git a/_plotly_utils/colors/__init__.py b/_plotly_utils/colors/__init__.py
index 254c8ce264f..193cb378e40 100644
--- a/_plotly_utils/colors/__init__.py
+++ b/_plotly_utils/colors/__init__.py
@@ -757,6 +757,8 @@ def hex_to_rgb(value):
     :rtype (tuple) (r_value, g_value, b_value): tuple of rgb values
     """
     value = value.lstrip("#")
+    if len(value) == 3:
+        value = "".join(c * 2 for c in value)
     hex_total_length = len(value)
     rgb_section_length = hex_total_length // 3
     return tuple(
diff --git a/plotly/matplotlylib/mpltools.py b/plotly/matplotlylib/mpltools.py
index 42681360030..0865a7df37a 100644
--- a/plotly/matplotlylib/mpltools.py
+++ b/plotly/matplotlylib/mpltools.py
@@ -117,6 +117,8 @@ def hex_to_rgb(value):
 
     """
     value = value.lstrip("#")
+    if len(value) == 3:
+        value = "".join(c * 2 for c in value)
     lv = len(value)
     return tuple(int(value[i : i + lv // 3], 16) for i in range(0, lv, lv // 3))
 
diff --git a/tests/test_plotly_utils/colors/test_color_conversions.py b/tests/test_plotly_utils/colors/test_color_conversions.py
index 282a81ce562..6513b7c3233 100644
--- a/tests/test_plotly_utils/colors/test_color_conversions.py
+++ b/tests/test_plotly_utils/colors/test_color_conversions.py
@@ -12,6 +12,15 @@ def test_hex_to_rgb_basic_values():
     assert hex_to_rgb("#aabbcc") == (170, 187, 204)
 
 
+def test_hex_to_rgb_shorthand_3_digit():
+    assert hex_to_rgb("#fff") == (255, 255, 255)
+    assert hex_to_rgb("#000") == (0, 0, 0)
+    assert hex_to_rgb("#abc") == (170, 187, 204)
+    assert hex_to_rgb("#f00") == (255, 0, 0)
+    assert hex_to_rgb("#0f0") == (0, 255, 0)
+    assert hex_to_rgb("#00f") == (0, 0, 255)
+
+
 def test_label_rgb_formats_tuple():
     assert label_rgb((255, 0, 0)) == "rgb(255, 0, 0)"
     assert label_rgb((1, 2, 3)) == "rgb(1, 2, 3)"

From 7f3b58cabc2e57175bbf94ed4b030b42284dcf12 Mon Sep 17 00:00:00 2001
From: Cameron DeCoster <cameron.decoster@gmail.com>
Date: Mon, 27 Jul 2026 15:13:02 -0600
Subject: [PATCH 2/3] Refactor to remove duplicate function

---
 _plotly_utils/colors/__init__.py |  9 ++++++++-
 plotly/matplotlylib/mpltools.py  | 21 ++-------------------
 2 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/_plotly_utils/colors/__init__.py b/_plotly_utils/colors/__init__.py
index 193cb378e40..e3b5cfa3205 100644
--- a/_plotly_utils/colors/__init__.py
+++ b/_plotly_utils/colors/__init__.py
@@ -752,9 +752,16 @@ def hex_to_rgb(value):
     """
     Calculates rgb values from a hex color code.
 
-    :param (string) value: Hex color string
+    :param (string) value: Hex color string. May be a full 6-character code
+        or a 3-character shorthand code.
 
     :rtype (tuple) (r_value, g_value, b_value): tuple of rgb values
+
+    Example:
+
+        '#FFFFFF' --> (255, 255, 255)
+        '#FFF'    --> (255, 255, 255)
+
     """
     value = value.lstrip("#")
     if len(value) == 3:
diff --git a/plotly/matplotlylib/mpltools.py b/plotly/matplotlylib/mpltools.py
index 0865a7df37a..0a3206998ba 100644
--- a/plotly/matplotlylib/mpltools.py
+++ b/plotly/matplotlylib/mpltools.py
@@ -10,6 +10,8 @@
 import warnings
 import matplotlib.dates
 
+from _plotly_utils.colors import hex_to_rgb
+
 
 def check_bar_match(old_bar, new_bar):
     """Check if two bars belong in the same collection (bar chart).
@@ -104,25 +106,6 @@ def convert_symbol(mpl_symbol):
         return "circle"  # default
 
 
-def hex_to_rgb(value):
-    """
-    Change a hex color to an rgb tuple
-
-    :param (str|unicode) value: The hex string we want to convert.
-    :return: (int, int, int) The red, green, blue int-tuple.
-
-    Example:
-
-        '#FFFFFF' --> (255, 255, 255)
-
-    """
-    value = value.lstrip("#")
-    if len(value) == 3:
-        value = "".join(c * 2 for c in value)
-    lv = len(value)
-    return tuple(int(value[i : i + lv // 3], 16) for i in range(0, lv, lv // 3))
-
-
 def merge_color_and_opacity(color, opacity):
     """
     Merge hex color with an alpha (opacity) to get an rgba tuple.

From 82fe3cf69a1e4ba38c288593952dd638904e82e9 Mon Sep 17 00:00:00 2001
From: genrichez <2.2434764e+07+genrichez@users.noreply.github.com>
Date: Mon, 27 Jul 2026 21:59:00 +0000
Subject: [PATCH 3/3] Add changelog entry for hex_to_rgb shorthand

---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e52c392dc79..9e39b670b5c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 
+### Fixed
+- Fix `hex_to_rgb` parsing of 3-digit shorthand hexadecimal colors such as `#FFF` [[#5662](https://github.com/plotly/plotly.py/pull/5662)], with thanks to @genrichez for the contribution!
+
 
 ## [6.9.0] - 2026-07-09