From 72292ac7d302d7bfa54c639879da01ab02528dfd Mon Sep 17 00:00:00 2001
From: Sriman Achanta <68172138+srimanachanta@users.noreply.github.com>
Date: Sun, 5 Feb 2023 17:09:32 -0500
Subject: [PATCH 01/10] added

---
 .../src/main/native/include/frc/util/Color.h   | 18 ++++++++++++++++++
 .../main/native/include/frc/util/Color8Bit.h   | 18 ++++++++++++++++++
 .../java/edu/wpi/first/wpilibj/util/Color.java | 16 ++++++++++++++++
 .../edu/wpi/first/wpilibj/util/Color8Bit.java  | 16 ++++++++++++++++
 4 files changed, 68 insertions(+)

diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index 87d8c12f497..f7020814ac1 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <algorithm>
+#include <stdexcept>
 #include <string>
 
 namespace frc {
@@ -811,6 +812,23 @@ class Color {
     }
   }
 
+  /**
+   * Create a Color from a hex string. Throws an exception if the Hex String is
+   * invalid.
+   *
+   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @return Color object from hex string.
+   */
+  static constexpr Color FromHexString(std::string hexString) {
+    if (hexString.length() != 7 || !hexString.starts_with("#")) {
+      throw std::invalid_argument("Invalid Hex String for Color");
+    }
+
+    int r, g, b;
+    std::sscanf(hexString.c_str(), "#%02x%02x%02x", &r, &g, &b);
+    return Color(r / 255, g / 255, b / 255);
+  }
+
   /**
    * Return this color represented as a hex string.
    *
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index 10afead93dc..2b7a57f408b 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <algorithm>
+#include <stdexcept>
 #include <string>
 
 #include "Color.h"
@@ -44,6 +45,23 @@ class Color8Bit {
     return Color(red / 255.0, green / 255.0, blue / 255.0);
   }
 
+  /**
+   * Create a Color8Bit from a hex string. Throws an exception if the Hex String
+   * is invalid.
+   *
+   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @return Color8Bit object from hex string.
+   */
+  static constexpr Color8Bit FromHexString(std::string hexString) {
+    if (hexString.length() != 7 || !hexString.starts_with("#")) {
+      throw std::invalid_argument("Invalid Hex String for Color");
+    }
+
+    int r, g, b;
+    std::sscanf(hexString.c_str(), "#%02x%02x%02x", &r, &g, &b);
+    return Color8Bit(r, g, b);
+  }
+
   constexpr bool operator==(const Color8Bit&) const = default;
 
   /**
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
index 2defbd8ad36..049b7e6e94e 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
@@ -115,6 +115,22 @@ public static Color fromHSV(int h, int s, int v) {
     }
   }
 
+  /**
+   * Create a Color from a hex string. Throws an exception if the Hex String is invalid.
+   *
+   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @return Color object from hex string.
+   */
+  public static Color fromHexString(String hexString) {
+    if (hexString.length() != 7 || !hexString.startsWith("#"))
+      throw new IllegalArgumentException("Invalid Hex String");
+
+    return new Color(
+        Integer.valueOf(hexString.substring(1, 3), 16) / 255.0,
+        Integer.valueOf(hexString.substring(3, 5), 16) / 255.0,
+        Integer.valueOf(hexString.substring(5, 7), 16) / 255.0);
+  }
+
   @Override
   public boolean equals(Object other) {
     if (this == other) {
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
index 32606731006..4246a55d1c0 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
@@ -36,6 +36,22 @@ public Color8Bit(Color color) {
     this((int) (color.red * 255), (int) (color.green * 255), (int) (color.blue * 255));
   }
 
+  /**
+   * Create a Color8Bit from a hex string. Throws an exception if the Hex String is invalid.
+   *
+   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @return Color8Bit object from hex string.
+   */
+  public static Color8Bit fromHexString(String hexString) {
+    if (hexString.length() != 7 || !hexString.startsWith("#"))
+      throw new IllegalArgumentException("Invalid Hex String");
+
+    return new Color8Bit(
+        Integer.valueOf(hexString.substring(1, 3), 16),
+        Integer.valueOf(hexString.substring(3, 5), 16),
+        Integer.valueOf(hexString.substring(5, 7), 16));
+  }
+
   @Override
   public boolean equals(Object other) {
     if (this == other) {

From 1ea9f33de850d83390673a990b8628af5725ced7 Mon Sep 17 00:00:00 2001
From: Sriman Achanta <68172138+srimanachanta@users.noreply.github.com>
Date: Sun, 5 Feb 2023 17:15:33 -0500
Subject: [PATCH 02/10] Fix documentation

---
 wpilibc/src/main/native/include/frc/util/Color.h     | 2 +-
 wpilibc/src/main/native/include/frc/util/Color8Bit.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index f7020814ac1..c18493ae688 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -816,7 +816,7 @@ class Color {
    * Create a Color from a hex string. Throws an exception if the Hex String is
    * invalid.
    *
-   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @param hexString a string of the format <tt>\#RRGGBB</tt>
    * @return Color object from hex string.
    */
   static constexpr Color FromHexString(std::string hexString) {
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index 2b7a57f408b..f1de75e1328 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -49,7 +49,7 @@ class Color8Bit {
    * Create a Color8Bit from a hex string. Throws an exception if the Hex String
    * is invalid.
    *
-   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @param hexString a string of the format <tt>\#RRGGBB</tt>
    * @return Color8Bit object from hex string.
    */
   static constexpr Color8Bit FromHexString(std::string hexString) {

From e259f59fb5e235fe394fd6853cfcc66a37426b85 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Thu, 30 Nov 2023 23:06:48 -0800
Subject: [PATCH 03/10] Address review comments for Color classes

---
 .../src/main/native/include/frc/util/Color.h  | 30 +++++++++++++------
 .../main/native/include/frc/util/Color8Bit.h  | 28 ++++++++++++-----
 .../edu/wpi/first/wpilibj/util/Color.java     | 14 +++++----
 .../edu/wpi/first/wpilibj/util/Color8Bit.java |  8 +++--
 4 files changed, 54 insertions(+), 26 deletions(-)

diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index c18493ae688..44f8f42c325 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -7,6 +7,10 @@
 #include <algorithm>
 #include <stdexcept>
 #include <string>
+#include <string_view>
+
+#include <fmt/core.h>
+#include <wpi/StringExtras.h>
 
 namespace frc {
 
@@ -813,20 +817,28 @@ class Color {
   }
 
   /**
-   * Create a Color from a hex string. Throws an exception if the Hex String is
-   * invalid.
+   * Create a Color from a hex string.
    *
    * @param hexString a string of the format <tt>\#RRGGBB</tt>
    * @return Color object from hex string.
-   */
-  static constexpr Color FromHexString(std::string hexString) {
-    if (hexString.length() != 7 || !hexString.starts_with("#")) {
-      throw std::invalid_argument("Invalid Hex String for Color");
+   * @throws std::invalid_argument if the hex string is invalid.
+   */
+  static constexpr Color FromHexString(std::string_view hexString) {
+    if (hexString.length() != 7 || !hexString.starts_with("#") ||
+        !wpi::isHexDigit(hexString[1]) || !wpi::isHexDigit(hexString[2]) ||
+        !wpi::isHexDigit(hexString[3]) || !wpi::isHexDigit(hexString[4]) ||
+        !wpi::isHexDigit(hexString[5]) || !wpi::isHexDigit(hexString[6])) {
+      throw std::invalid_argument(
+          fmt::format("Invalid hex string for Color \"{}\"", hexString));
     }
 
-    int r, g, b;
-    std::sscanf(hexString.c_str(), "#%02x%02x%02x", &r, &g, &b);
-    return Color(r / 255, g / 255, b / 255);
+    int r = wpi::hexDigitValue(hexString[0]) * 16 +
+            wpi::hexDigitValue(hexString[1]);
+    int g = wpi::hexDigitValue(hexString[2]) * 16 +
+            wpi::hexDigitValue(hexString[3]);
+    int b = wpi::hexDigitValue(hexString[4]) * 16 +
+            wpi::hexDigitValue(hexString[5]);
+    return Color{r, g, b};
   }
 
   /**
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index f1de75e1328..65aa7c557c4 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -7,6 +7,10 @@
 #include <algorithm>
 #include <stdexcept>
 #include <string>
+#include <string_view>
+
+#include <fmt/core.h>
+#include <wpi/StringExtras.h>
 
 #include "Color.h"
 
@@ -46,20 +50,28 @@ class Color8Bit {
   }
 
   /**
-   * Create a Color8Bit from a hex string. Throws an exception if the Hex String
-   * is invalid.
+   * Create a Color8Bit from a hex string.
    *
    * @param hexString a string of the format <tt>\#RRGGBB</tt>
    * @return Color8Bit object from hex string.
+   * @throws std::invalid_argument if the hex string is invalid.
    */
-  static constexpr Color8Bit FromHexString(std::string hexString) {
-    if (hexString.length() != 7 || !hexString.starts_with("#")) {
-      throw std::invalid_argument("Invalid Hex String for Color");
+  static constexpr Color8Bit FromHexString(std::string_view hexString) {
+    if (hexString.length() != 7 || !hexString.starts_with("#") ||
+        !wpi::isHexDigit(hexString[1]) || !wpi::isHexDigit(hexString[2]) ||
+        !wpi::isHexDigit(hexString[3]) || !wpi::isHexDigit(hexString[4]) ||
+        !wpi::isHexDigit(hexString[5]) || !wpi::isHexDigit(hexString[6])) {
+      throw std::invalid_argument(
+          fmt::format("Invalid hex string for Color \"{}\"", hexString));
     }
 
-    int r, g, b;
-    std::sscanf(hexString.c_str(), "#%02x%02x%02x", &r, &g, &b);
-    return Color8Bit(r, g, b);
+    int r = wpi::hexDigitValue(hexString[0]) * 16 +
+            wpi::hexDigitValue(hexString[1]);
+    int g = wpi::hexDigitValue(hexString[2]) * 16 +
+            wpi::hexDigitValue(hexString[3]);
+    int b = wpi::hexDigitValue(hexString[4]) * 16 +
+            wpi::hexDigitValue(hexString[5]);
+    return Color8Bit{r, g, b};
   }
 
   constexpr bool operator==(const Color8Bit&) const = default;
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
index 049b7e6e94e..98b8da63bff 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
@@ -116,19 +116,21 @@ public static Color fromHSV(int h, int s, int v) {
   }
 
   /**
-   * Create a Color from a hex string. Throws an exception if the Hex String is invalid.
+   * Create a Color from a hex string.
    *
    * @param hexString a string of the format <code>#RRGGBB</code>
    * @return Color object from hex string.
+   * @throws IllegalArgumentException if the hex string is invalid.
    */
   public static Color fromHexString(String hexString) {
-    if (hexString.length() != 7 || !hexString.startsWith("#"))
-      throw new IllegalArgumentException("Invalid Hex String");
+    if (hexString.length() != 7 || !hexString.startsWith("#")) {
+      throw new IllegalArgumentException("Invalid hex string \"" + hexString + "\"");
+    }
 
     return new Color(
-        Integer.valueOf(hexString.substring(1, 3), 16) / 255.0,
-        Integer.valueOf(hexString.substring(3, 5), 16) / 255.0,
-        Integer.valueOf(hexString.substring(5, 7), 16) / 255.0);
+        Integer.valueOf(hexString.substring(1, 3), 16),
+        Integer.valueOf(hexString.substring(3, 5), 16),
+        Integer.valueOf(hexString.substring(5, 7), 16));
   }
 
   @Override
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
index 4246a55d1c0..8e018ad5e4a 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
@@ -37,14 +37,16 @@ public Color8Bit(Color color) {
   }
 
   /**
-   * Create a Color8Bit from a hex string. Throws an exception if the Hex String is invalid.
+   * Create a Color8Bit from a hex string.
    *
    * @param hexString a string of the format <code>#RRGGBB</code>
    * @return Color8Bit object from hex string.
+   * @throws IllegalArgumentException if the hex string is invalid.
    */
   public static Color8Bit fromHexString(String hexString) {
-    if (hexString.length() != 7 || !hexString.startsWith("#"))
-      throw new IllegalArgumentException("Invalid Hex String");
+    if (hexString.length() != 7 || !hexString.startsWith("#")) {
+      throw new IllegalArgumentException("Invalid hex string \"" + hexString + "\"");
+    }
 
     return new Color8Bit(
         Integer.valueOf(hexString.substring(1, 3), 16),

From b26bd0ca4b344223def7c8e590b8dfab341faf7d Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 00:02:04 -0800
Subject: [PATCH 04/10] Make hex string conversion constexpr and add test stubs

---
 wpilibc/src/main/native/cpp/util/Color.cpp    | 15 -----------
 .../src/main/native/cpp/util/Color8Bit.cpp    | 13 ---------
 .../src/main/native/include/frc/util/Color.h  | 22 ++++++++++++++-
 .../main/native/include/frc/util/Color8Bit.h  | 22 ++++++++++++---
 .../test/native/cpp/util/Color8BitTest.cpp    | 19 +++++++++++++
 .../src/test/native/cpp/util/ColorTest.cpp    | 19 +++++++++++++
 .../wpi/first/wpilibj/util/Color8BitTest.java | 24 +++++++++++++++++
 .../edu/wpi/first/wpilibj/util/ColorTest.java | 27 +++++++++++++++++++
 8 files changed, 129 insertions(+), 32 deletions(-)
 delete mode 100644 wpilibc/src/main/native/cpp/util/Color.cpp
 delete mode 100644 wpilibc/src/main/native/cpp/util/Color8Bit.cpp
 create mode 100644 wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
 create mode 100644 wpilibc/src/test/native/cpp/util/ColorTest.cpp
 create mode 100644 wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
 create mode 100644 wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java

diff --git a/wpilibc/src/main/native/cpp/util/Color.cpp b/wpilibc/src/main/native/cpp/util/Color.cpp
deleted file mode 100644
index e3adaf2db3f..00000000000
--- a/wpilibc/src/main/native/cpp/util/Color.cpp
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright (c) FIRST and other WPILib contributors.
-// Open Source Software; you can modify and/or share it under the terms of
-// the WPILib BSD license file in the root directory of this project.
-
-#include "frc/util/Color.h"
-
-#include <fmt/format.h>
-
-using namespace frc;
-
-std::string Color::HexString() const {
-  return fmt::format("#{:02X}{:02X}{:02X}", static_cast<int>(255.0 * red),
-                     static_cast<int>(255.0 * green),
-                     static_cast<int>(255.0 * blue));
-}
diff --git a/wpilibc/src/main/native/cpp/util/Color8Bit.cpp b/wpilibc/src/main/native/cpp/util/Color8Bit.cpp
deleted file mode 100644
index af200a294b5..00000000000
--- a/wpilibc/src/main/native/cpp/util/Color8Bit.cpp
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright (c) FIRST and other WPILib contributors.
-// Open Source Software; you can modify and/or share it under the terms of
-// the WPILib BSD license file in the root directory of this project.
-
-#include "frc/util/Color8Bit.h"
-
-#include <fmt/format.h>
-
-using namespace frc;
-
-std::string Color8Bit::HexString() const {
-  return fmt::format("#{:02X}{:02X}{:02X}", red, green, blue);
-}
diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index 44f8f42c325..b51e462d405 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -8,6 +8,7 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
+#include <type_traits>
 
 #include <fmt/core.h>
 #include <wpi/StringExtras.h>
@@ -846,7 +847,26 @@ class Color {
    *
    * @return a string of the format <tt>\#RRGGBB</tt>
    */
-  std::string HexString() const;
+  constexpr std::string HexString() const {
+    int r = static_cast<int>(255.0 * red);
+    int g = static_cast<int>(255.0 * green);
+    int b = static_cast<int>(255.0 * blue);
+
+    if (std::is_constant_evaluated()) {
+      std::string str = "#";
+
+      str += wpi::hexdigit(r / 16);
+      str += wpi::hexdigit(r % 16);
+      str += wpi::hexdigit(g / 16);
+      str += wpi::hexdigit(g % 16);
+      str += wpi::hexdigit(b / 16);
+      str += wpi::hexdigit(b % 16);
+
+      return str;
+    } else {
+      return fmt::format("#{:02X}{:02X}{:02X}", r, g, b);
+    }
+  }
 
   double red = 0.0;
   double green = 0.0;
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index 65aa7c557c4..520969e7799 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -8,6 +8,7 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
+#include <type_traits>
 
 #include <fmt/core.h>
 #include <wpi/StringExtras.h>
@@ -45,6 +46,8 @@ class Color8Bit {
         green(color.green * 255),
         blue(color.blue * 255) {}
 
+  constexpr bool operator==(const Color8Bit&) const = default;
+
   constexpr operator Color() const {  // NOLINT
     return Color(red / 255.0, green / 255.0, blue / 255.0);
   }
@@ -74,14 +77,27 @@ class Color8Bit {
     return Color8Bit{r, g, b};
   }
 
-  constexpr bool operator==(const Color8Bit&) const = default;
-
   /**
    * Return this color represented as a hex string.
    *
    * @return a string of the format <tt>\#RRGGBB</tt>
    */
-  std::string HexString() const;
+  constexpr std::string HexString() const {
+    if (std::is_constant_evaluated()) {
+      std::string str = "#";
+
+      str += wpi::hexdigit(red / 16);
+      str += wpi::hexdigit(red % 16);
+      str += wpi::hexdigit(green / 16);
+      str += wpi::hexdigit(green % 16);
+      str += wpi::hexdigit(blue / 16);
+      str += wpi::hexdigit(blue % 16);
+
+      return str;
+    } else {
+      return fmt::format("#{:02X}{:02X}{:02X}", red, green, blue);
+    }
+  }
 
   int red = 0;
   int green = 0;
diff --git a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
new file mode 100644
index 00000000000..bb59eb54b6b
--- /dev/null
+++ b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
@@ -0,0 +1,19 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <gtest/gtest.h>
+
+#include "frc/util/Color8Bit.h"
+
+TEST(Color8BitTest, ConstructDefault) {}
+
+TEST(Color8BitTest, ConstructFromInts) {}
+
+TEST(Color8BitTest, ConstructFromColor) {}
+
+TEST(Color8BitTest, ImplicitConversionToColor) {}
+
+TEST(Color8BitTest, FromHexString) {}
+
+TEST(Color8BitTest, HexString) {}
diff --git a/wpilibc/src/test/native/cpp/util/ColorTest.cpp b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
new file mode 100644
index 00000000000..b01ef7dc620
--- /dev/null
+++ b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
@@ -0,0 +1,19 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <gtest/gtest.h>
+
+#include "frc/util/Color.h"
+
+TEST(ColorTest, ConstructDefault) {}
+
+TEST(ColorTest, ConstructFromDoubles) {}
+
+TEST(ColorTest, ConstructFromInts) {}
+
+TEST(ColorTest, FromHSV) {}
+
+TEST(ColorTest, FromHexString) {}
+
+TEST(ColorTest, HexString) {}
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
new file mode 100644
index 00000000000..9b9d44d078c
--- /dev/null
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
@@ -0,0 +1,24 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.wpilibj;
+
+import org.junit.jupiter.api.Test;
+
+class Color8BitTest {
+  @Test
+  void testConstructDefault() {}
+
+  @Test
+  void testConstructFromInts() {}
+
+  @Test
+  void testConstructFromColor() {}
+
+  @Test
+  void testFromHexString() {}
+
+  @Test
+  void testHexString() {}
+}
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
new file mode 100644
index 00000000000..2d9f899a82a
--- /dev/null
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
@@ -0,0 +1,27 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.wpilibj;
+
+import org.junit.jupiter.api.Test;
+
+class ColorTest {
+  @Test
+  void testConstructDefault() {}
+
+  @Test
+  void testConstructFromDoubles() {}
+
+  @Test
+  void testConstructFromInts() {}
+
+  @Test
+  void testFromHSV() {}
+
+  @Test
+  void testFromHexString() {}
+
+  @Test
+  void testHexString() {}
+}

From 3fbcb9cad71442960333570e3c695253973818ee Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 00:08:17 -0800
Subject: [PATCH 05/10] Fix test package

---
 .../src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java | 2 +-
 wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
index 9b9d44d078c..c9badc093d9 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.first.wpilibj;
+package edu.wpi.first.wpilibj.util;
 
 import org.junit.jupiter.api.Test;
 
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
index 2d9f899a82a..901b6483ff1 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.first.wpilibj;
+package edu.wpi.first.wpilibj.util;
 
 import org.junit.jupiter.api.Test;
 

From b572e4bb98e7bfbc9a00c7cffb051975dbdbe98a Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 00:17:26 -0800
Subject: [PATCH 06/10] Make hex string factory a constructor

---
 .../src/main/native/include/frc/util/Color.h  | 52 ++++++++++---------
 .../main/native/include/frc/util/Color8Bit.h  | 23 ++++++++
 .../test/native/cpp/util/Color8BitTest.cpp    |  4 +-
 .../src/test/native/cpp/util/ColorTest.cpp    |  4 +-
 .../edu/wpi/first/wpilibj/util/Color.java     | 34 ++++++------
 .../edu/wpi/first/wpilibj/util/Color8Bit.java | 12 ++---
 .../wpi/first/wpilibj/util/Color8BitTest.java |  2 +-
 .../edu/wpi/first/wpilibj/util/ColorTest.java |  4 +-
 8 files changed, 78 insertions(+), 57 deletions(-)

diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index b51e462d405..dcd8489fc04 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -769,6 +769,33 @@ class Color {
   constexpr Color(int r, int g, int b)
       : Color(r / 255.0, g / 255.0, b / 255.0) {}
 
+  /**
+   * Constructs a Color from a hex string.
+   *
+   * @param hexString a string of the format <tt>\#RRGGBB</tt>
+   * @throws std::invalid_argument if the hex string is invalid.
+   */
+  explicit constexpr Color(std::string_view hexString) {
+    if (hexString.length() != 7 || !hexString.starts_with("#") ||
+        !wpi::isHexDigit(hexString[1]) || !wpi::isHexDigit(hexString[2]) ||
+        !wpi::isHexDigit(hexString[3]) || !wpi::isHexDigit(hexString[4]) ||
+        !wpi::isHexDigit(hexString[5]) || !wpi::isHexDigit(hexString[6])) {
+      throw std::invalid_argument(
+          fmt::format("Invalid hex string for Color \"{}\"", hexString));
+    }
+
+    int r = wpi::hexDigitValue(hexString[0]) * 16 +
+            wpi::hexDigitValue(hexString[1]);
+    int g = wpi::hexDigitValue(hexString[2]) * 16 +
+            wpi::hexDigitValue(hexString[3]);
+    int b = wpi::hexDigitValue(hexString[4]) * 16 +
+            wpi::hexDigitValue(hexString[5]);
+
+    red = r / 255.0;
+    green = g / 255.0;
+    blue = b / 255.0;
+  }
+
   constexpr bool operator==(const Color&) const = default;
 
   /**
@@ -817,31 +844,6 @@ class Color {
     }
   }
 
-  /**
-   * Create a Color from a hex string.
-   *
-   * @param hexString a string of the format <tt>\#RRGGBB</tt>
-   * @return Color object from hex string.
-   * @throws std::invalid_argument if the hex string is invalid.
-   */
-  static constexpr Color FromHexString(std::string_view hexString) {
-    if (hexString.length() != 7 || !hexString.starts_with("#") ||
-        !wpi::isHexDigit(hexString[1]) || !wpi::isHexDigit(hexString[2]) ||
-        !wpi::isHexDigit(hexString[3]) || !wpi::isHexDigit(hexString[4]) ||
-        !wpi::isHexDigit(hexString[5]) || !wpi::isHexDigit(hexString[6])) {
-      throw std::invalid_argument(
-          fmt::format("Invalid hex string for Color \"{}\"", hexString));
-    }
-
-    int r = wpi::hexDigitValue(hexString[0]) * 16 +
-            wpi::hexDigitValue(hexString[1]);
-    int g = wpi::hexDigitValue(hexString[2]) * 16 +
-            wpi::hexDigitValue(hexString[3]);
-    int b = wpi::hexDigitValue(hexString[4]) * 16 +
-            wpi::hexDigitValue(hexString[5]);
-    return Color{r, g, b};
-  }
-
   /**
    * Return this color represented as a hex string.
    *
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index 520969e7799..d41a113dc64 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -46,6 +46,29 @@ class Color8Bit {
         green(color.green * 255),
         blue(color.blue * 255) {}
 
+  /**
+   * Constructs a Color8Bit from a hex string.
+   *
+   * @param hexString a string of the format <tt>\#RRGGBB</tt>
+   * @throws std::invalid_argument if the hex string is invalid.
+   */
+  explicit constexpr Color8Bit(std::string_view hexString) {
+    if (hexString.length() != 7 || !hexString.starts_with("#") ||
+        !wpi::isHexDigit(hexString[1]) || !wpi::isHexDigit(hexString[2]) ||
+        !wpi::isHexDigit(hexString[3]) || !wpi::isHexDigit(hexString[4]) ||
+        !wpi::isHexDigit(hexString[5]) || !wpi::isHexDigit(hexString[6])) {
+      throw std::invalid_argument(
+          fmt::format("Invalid hex string for Color \"{}\"", hexString));
+    }
+
+    red = wpi::hexDigitValue(hexString[0]) * 16 +
+          wpi::hexDigitValue(hexString[1]);
+    green = wpi::hexDigitValue(hexString[2]) * 16 +
+            wpi::hexDigitValue(hexString[3]);
+    blue = wpi::hexDigitValue(hexString[4]) * 16 +
+           wpi::hexDigitValue(hexString[5]);
+  }
+
   constexpr bool operator==(const Color8Bit&) const = default;
 
   constexpr operator Color() const {  // NOLINT
diff --git a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
index bb59eb54b6b..544a8a1dbbb 100644
--- a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
+++ b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
@@ -12,8 +12,8 @@ TEST(Color8BitTest, ConstructFromInts) {}
 
 TEST(Color8BitTest, ConstructFromColor) {}
 
-TEST(Color8BitTest, ImplicitConversionToColor) {}
+TEST(Color8BitTest, ConstructFromHexString) {}
 
-TEST(Color8BitTest, FromHexString) {}
+TEST(Color8BitTest, ImplicitConversionToColor) {}
 
 TEST(Color8BitTest, HexString) {}
diff --git a/wpilibc/src/test/native/cpp/util/ColorTest.cpp b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
index b01ef7dc620..675cf13626b 100644
--- a/wpilibc/src/test/native/cpp/util/ColorTest.cpp
+++ b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
@@ -12,8 +12,8 @@ TEST(ColorTest, ConstructFromDoubles) {}
 
 TEST(ColorTest, ConstructFromInts) {}
 
-TEST(ColorTest, FromHSV) {}
+TEST(ColorTest, ConstructFromHexString) {}
 
-TEST(ColorTest, FromHexString) {}
+TEST(ColorTest, FromHSV) {}
 
 TEST(ColorTest, HexString) {}
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
index 98b8da63bff..c9787325fa8 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
@@ -69,6 +69,22 @@ private Color(double red, double green, double blue, String name) {
     this.m_name = name;
   }
 
+  /**
+   * Constructs a Color from a hex string.
+   *
+   * @param hexString a string of the format <code>#RRGGBB</code>
+   * @throws IllegalArgumentException if the hex string is invalid.
+   */
+  public Color(String hexString) {
+    if (hexString.length() != 7 || !hexString.startsWith("#")) {
+      throw new IllegalArgumentException("Invalid hex string \"" + hexString + "\"");
+    }
+
+    this.red = Integer.valueOf(hexString.substring(1, 3), 16) / 255.0;
+    this.green = Integer.valueOf(hexString.substring(3, 5), 16) / 255.0;
+    this.blue = Integer.valueOf(hexString.substring(5, 7), 16) / 255.0;
+  }
+
   /**
    * Creates a Color from HSV values.
    *
@@ -115,24 +131,6 @@ public static Color fromHSV(int h, int s, int v) {
     }
   }
 
-  /**
-   * Create a Color from a hex string.
-   *
-   * @param hexString a string of the format <code>#RRGGBB</code>
-   * @return Color object from hex string.
-   * @throws IllegalArgumentException if the hex string is invalid.
-   */
-  public static Color fromHexString(String hexString) {
-    if (hexString.length() != 7 || !hexString.startsWith("#")) {
-      throw new IllegalArgumentException("Invalid hex string \"" + hexString + "\"");
-    }
-
-    return new Color(
-        Integer.valueOf(hexString.substring(1, 3), 16),
-        Integer.valueOf(hexString.substring(3, 5), 16),
-        Integer.valueOf(hexString.substring(5, 7), 16));
-  }
-
   @Override
   public boolean equals(Object other) {
     if (this == other) {
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
index 8e018ad5e4a..e9e0e8880b3 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
@@ -37,21 +37,19 @@ public Color8Bit(Color color) {
   }
 
   /**
-   * Create a Color8Bit from a hex string.
+   * Constructs a Color8Bit from a hex string.
    *
    * @param hexString a string of the format <code>#RRGGBB</code>
-   * @return Color8Bit object from hex string.
    * @throws IllegalArgumentException if the hex string is invalid.
    */
-  public static Color8Bit fromHexString(String hexString) {
+  public Color8Bit(String hexString) {
     if (hexString.length() != 7 || !hexString.startsWith("#")) {
       throw new IllegalArgumentException("Invalid hex string \"" + hexString + "\"");
     }
 
-    return new Color8Bit(
-        Integer.valueOf(hexString.substring(1, 3), 16),
-        Integer.valueOf(hexString.substring(3, 5), 16),
-        Integer.valueOf(hexString.substring(5, 7), 16));
+    this.red = Integer.valueOf(hexString.substring(1, 3), 16);
+    this.green = Integer.valueOf(hexString.substring(3, 5), 16);
+    this.blue = Integer.valueOf(hexString.substring(5, 7), 16);
   }
 
   @Override
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
index c9badc093d9..16c66c07367 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
@@ -17,7 +17,7 @@ void testConstructFromInts() {}
   void testConstructFromColor() {}
 
   @Test
-  void testFromHexString() {}
+  void testConstructFromHexString() {}
 
   @Test
   void testHexString() {}
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
index 901b6483ff1..f2a8b30978a 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
@@ -17,10 +17,10 @@ void testConstructFromDoubles() {}
   void testConstructFromInts() {}
 
   @Test
-  void testFromHSV() {}
+  void testConstructFromHexString() {}
 
   @Test
-  void testFromHexString() {}
+  void testFromHSV() {}
 
   @Test
   void testHexString() {}

From e2dcdcd2ca1e1eadb5c3114d7a14ab29f5315046 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 00:20:09 -0800
Subject: [PATCH 07/10] Rename tests

---
 wpilibc/src/test/native/cpp/util/Color8BitTest.cpp              | 2 +-
 wpilibc/src/test/native/cpp/util/ColorTest.cpp                  | 2 +-
 .../src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java | 2 +-
 wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
index 544a8a1dbbb..69e36fbe4f0 100644
--- a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
+++ b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
@@ -16,4 +16,4 @@ TEST(Color8BitTest, ConstructFromHexString) {}
 
 TEST(Color8BitTest, ImplicitConversionToColor) {}
 
-TEST(Color8BitTest, HexString) {}
+TEST(Color8BitTest, ToHexString) {}
diff --git a/wpilibc/src/test/native/cpp/util/ColorTest.cpp b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
index 675cf13626b..9b9eea7e078 100644
--- a/wpilibc/src/test/native/cpp/util/ColorTest.cpp
+++ b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
@@ -16,4 +16,4 @@ TEST(ColorTest, ConstructFromHexString) {}
 
 TEST(ColorTest, FromHSV) {}
 
-TEST(ColorTest, HexString) {}
+TEST(ColorTest, ToHexString) {}
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
index 16c66c07367..42abf020d76 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
@@ -20,5 +20,5 @@ void testConstructFromColor() {}
   void testConstructFromHexString() {}
 
   @Test
-  void testHexString() {}
+  void testToHexString() {}
 }
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
index f2a8b30978a..fdd8fbd6870 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
@@ -23,5 +23,5 @@ void testConstructFromHexString() {}
   void testFromHSV() {}
 
   @Test
-  void testHexString() {}
+  void testToHexString() {}
 }

From fc3cbe307bdf0033ae1d3f797f3a8fcfb3f94eab Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 08:45:57 -0800
Subject: [PATCH 08/10] Make HexString() not constexpr

---
 .../src/main/native/include/frc/util/Color.h  | 24 ++++---------------
 .../main/native/include/frc/util/Color8Bit.h  | 18 ++------------
 2 files changed, 6 insertions(+), 36 deletions(-)

diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index dcd8489fc04..e9d7a53070e 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -8,7 +8,6 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
-#include <type_traits>
 
 #include <fmt/core.h>
 #include <wpi/StringExtras.h>
@@ -849,25 +848,10 @@ class Color {
    *
    * @return a string of the format <tt>\#RRGGBB</tt>
    */
-  constexpr std::string HexString() const {
-    int r = static_cast<int>(255.0 * red);
-    int g = static_cast<int>(255.0 * green);
-    int b = static_cast<int>(255.0 * blue);
-
-    if (std::is_constant_evaluated()) {
-      std::string str = "#";
-
-      str += wpi::hexdigit(r / 16);
-      str += wpi::hexdigit(r % 16);
-      str += wpi::hexdigit(g / 16);
-      str += wpi::hexdigit(g % 16);
-      str += wpi::hexdigit(b / 16);
-      str += wpi::hexdigit(b % 16);
-
-      return str;
-    } else {
-      return fmt::format("#{:02X}{:02X}{:02X}", r, g, b);
-    }
+  std::string HexString() const {
+    return fmt::format("#{:02X}{:02X}{:02X}", static_cast<int>(255.0 * red),
+                       static_cast<int>(255.0 * green),
+                       static_cast<int>(255.0 * blue));
   }
 
   double red = 0.0;
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index d41a113dc64..5ea92e29806 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -8,7 +8,6 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
-#include <type_traits>
 
 #include <fmt/core.h>
 #include <wpi/StringExtras.h>
@@ -105,21 +104,8 @@ class Color8Bit {
    *
    * @return a string of the format <tt>\#RRGGBB</tt>
    */
-  constexpr std::string HexString() const {
-    if (std::is_constant_evaluated()) {
-      std::string str = "#";
-
-      str += wpi::hexdigit(red / 16);
-      str += wpi::hexdigit(red % 16);
-      str += wpi::hexdigit(green / 16);
-      str += wpi::hexdigit(green % 16);
-      str += wpi::hexdigit(blue / 16);
-      str += wpi::hexdigit(blue % 16);
-
-      return str;
-    } else {
-      return fmt::format("#{:02X}{:02X}{:02X}", red, green, blue);
-    }
+  std::string HexString() const {
+    return fmt::format("#{:02X}{:02X}{:02X}", red, green, blue);
   }
 
   int red = 0;

From 8f68b66bb9974af38a633050ea0fcbce2c52b7c5 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 09:33:54 -0800
Subject: [PATCH 09/10] Add tests

---
 .../src/main/native/include/frc/util/Color.h  | 15 +++--
 .../main/native/include/frc/util/Color8Bit.h  | 15 +++--
 .../test/native/cpp/util/Color8BitTest.cpp    | 55 +++++++++++++++--
 .../src/test/native/cpp/util/ColorTest.cpp    | 55 +++++++++++++++--
 .../edu/wpi/first/wpilibj/util/Color.java     |  7 +++
 .../edu/wpi/first/wpilibj/util/Color8Bit.java |  7 +++
 .../wpi/first/wpilibj/util/Color8BitTest.java | 51 ++++++++++++++--
 .../edu/wpi/first/wpilibj/util/ColorTest.java | 59 +++++++++++++++++--
 8 files changed, 229 insertions(+), 35 deletions(-)

diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index e9d7a53070e..3e4567373d7 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -744,6 +744,9 @@ class Color {
    */
   static const Color kYellowGreen;
 
+  /**
+   * Constructs a default color (black).
+   */
   constexpr Color() = default;
 
   /**
@@ -783,12 +786,12 @@ class Color {
           fmt::format("Invalid hex string for Color \"{}\"", hexString));
     }
 
-    int r = wpi::hexDigitValue(hexString[0]) * 16 +
-            wpi::hexDigitValue(hexString[1]);
-    int g = wpi::hexDigitValue(hexString[2]) * 16 +
-            wpi::hexDigitValue(hexString[3]);
-    int b = wpi::hexDigitValue(hexString[4]) * 16 +
-            wpi::hexDigitValue(hexString[5]);
+    int r = wpi::hexDigitValue(hexString[1]) * 16 +
+            wpi::hexDigitValue(hexString[2]);
+    int g = wpi::hexDigitValue(hexString[3]) * 16 +
+            wpi::hexDigitValue(hexString[4]);
+    int b = wpi::hexDigitValue(hexString[5]) * 16 +
+            wpi::hexDigitValue(hexString[6]);
 
     red = r / 255.0;
     green = g / 255.0;
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index 5ea92e29806..559559bcd14 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -21,6 +21,9 @@ namespace frc {
  */
 class Color8Bit {
  public:
+  /**
+   * Constructs a default color (black).
+   */
   constexpr Color8Bit() = default;
 
   /**
@@ -60,12 +63,12 @@ class Color8Bit {
           fmt::format("Invalid hex string for Color \"{}\"", hexString));
     }
 
-    red = wpi::hexDigitValue(hexString[0]) * 16 +
-          wpi::hexDigitValue(hexString[1]);
-    green = wpi::hexDigitValue(hexString[2]) * 16 +
-            wpi::hexDigitValue(hexString[3]);
-    blue = wpi::hexDigitValue(hexString[4]) * 16 +
-           wpi::hexDigitValue(hexString[5]);
+    red = wpi::hexDigitValue(hexString[1]) * 16 +
+          wpi::hexDigitValue(hexString[2]);
+    green = wpi::hexDigitValue(hexString[3]) * 16 +
+            wpi::hexDigitValue(hexString[4]);
+    blue = wpi::hexDigitValue(hexString[5]) * 16 +
+           wpi::hexDigitValue(hexString[6]);
   }
 
   constexpr bool operator==(const Color8Bit&) const = default;
diff --git a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
index 69e36fbe4f0..e0b26dd5790 100644
--- a/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
+++ b/wpilibc/src/test/native/cpp/util/Color8BitTest.cpp
@@ -6,14 +6,57 @@
 
 #include "frc/util/Color8Bit.h"
 
-TEST(Color8BitTest, ConstructDefault) {}
+TEST(Color8BitTest, ConstructDefault) {
+  constexpr frc::Color8Bit color;
 
-TEST(Color8BitTest, ConstructFromInts) {}
+  EXPECT_EQ(0, color.red);
+  EXPECT_EQ(0, color.green);
+  EXPECT_EQ(0, color.blue);
+}
 
-TEST(Color8BitTest, ConstructFromColor) {}
+TEST(Color8BitTest, ConstructFromInts) {
+  constexpr frc::Color8Bit color{255, 128, 64};
 
-TEST(Color8BitTest, ConstructFromHexString) {}
+  EXPECT_EQ(255, color.red);
+  EXPECT_EQ(128, color.green);
+  EXPECT_EQ(64, color.blue);
+}
 
-TEST(Color8BitTest, ImplicitConversionToColor) {}
+TEST(Color8BitTest, ConstructFromColor) {
+  constexpr frc::Color8Bit color{frc::Color{255, 128, 64}};
 
-TEST(Color8BitTest, ToHexString) {}
+  EXPECT_EQ(255, color.red);
+  EXPECT_EQ(128, color.green);
+  EXPECT_EQ(64, color.blue);
+}
+
+TEST(Color8BitTest, ConstructFromHexString) {
+  constexpr frc::Color8Bit color{"#FF8040"};
+
+  EXPECT_EQ(255, color.red);
+  EXPECT_EQ(128, color.green);
+  EXPECT_EQ(64, color.blue);
+
+  // No leading #
+  EXPECT_THROW(frc::Color8Bit{"112233"}, std::invalid_argument);
+
+  // Too long
+  EXPECT_THROW(frc::Color8Bit{"#11223344"}, std::invalid_argument);
+
+  // Invalid hex characters
+  EXPECT_THROW(frc::Color8Bit{"#$$$$$$"}, std::invalid_argument);
+}
+
+TEST(Color8BitTest, ImplicitConversionToColor) {
+  frc::Color color = frc::Color8Bit{255, 128, 64};
+
+  EXPECT_NEAR(1.0, color.red, 1e-2);
+  EXPECT_NEAR(0.5, color.green, 1e-2);
+  EXPECT_NEAR(0.25, color.blue, 1e-2);
+}
+
+TEST(Color8BitTest, ToHexString) {
+  constexpr frc::Color8Bit color{255, 128, 64};
+
+  EXPECT_EQ("#FF8040", color.HexString());
+}
diff --git a/wpilibc/src/test/native/cpp/util/ColorTest.cpp b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
index 9b9eea7e078..c76c7f1da29 100644
--- a/wpilibc/src/test/native/cpp/util/ColorTest.cpp
+++ b/wpilibc/src/test/native/cpp/util/ColorTest.cpp
@@ -6,14 +6,57 @@
 
 #include "frc/util/Color.h"
 
-TEST(ColorTest, ConstructDefault) {}
+TEST(ColorTest, ConstructDefault) {
+  constexpr frc::Color color;
 
-TEST(ColorTest, ConstructFromDoubles) {}
+  EXPECT_DOUBLE_EQ(0.0, color.red);
+  EXPECT_DOUBLE_EQ(0.0, color.green);
+  EXPECT_DOUBLE_EQ(0.0, color.blue);
+}
 
-TEST(ColorTest, ConstructFromInts) {}
+TEST(ColorTest, ConstructFromDoubles) {
+  constexpr frc::Color color{1.0, 0.5, 0.25};
 
-TEST(ColorTest, ConstructFromHexString) {}
+  EXPECT_NEAR(1.0, color.red, 1e-2);
+  EXPECT_NEAR(0.5, color.green, 1e-2);
+  EXPECT_NEAR(0.25, color.blue, 1e-2);
+}
 
-TEST(ColorTest, FromHSV) {}
+TEST(ColorTest, ConstructFromInts) {
+  constexpr frc::Color color{255, 128, 64};
 
-TEST(ColorTest, ToHexString) {}
+  EXPECT_NEAR(1.0, color.red, 1e-2);
+  EXPECT_NEAR(0.5, color.green, 1e-2);
+  EXPECT_NEAR(0.25, color.blue, 1e-2);
+}
+
+TEST(ColorTest, ConstructFromHexString) {
+  constexpr frc::Color color{"#FF8040"};
+
+  EXPECT_NEAR(1.0, color.red, 1e-2);
+  EXPECT_NEAR(0.5, color.green, 1e-2);
+  EXPECT_NEAR(0.25, color.blue, 1e-2);
+
+  // No leading #
+  EXPECT_THROW(frc::Color{"112233"}, std::invalid_argument);
+
+  // Too long
+  EXPECT_THROW(frc::Color{"#11223344"}, std::invalid_argument);
+
+  // Invalid hex characters
+  EXPECT_THROW(frc::Color{"#$$$$$$"}, std::invalid_argument);
+}
+
+TEST(ColorTest, FromHSV) {
+  constexpr frc::Color color = frc::Color::FromHSV(90, 128, 64);
+
+  EXPECT_DOUBLE_EQ(0.1256103515625, color.red);
+  EXPECT_DOUBLE_EQ(0.2510986328125, color.green);
+  EXPECT_DOUBLE_EQ(0.2510986328125, color.blue);
+}
+
+TEST(ColorTest, ToHexString) {
+  constexpr frc::Color color{255, 128, 64};
+
+  EXPECT_EQ("#FF8040", color.HexString());
+}
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
index c9787325fa8..706795dd701 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color.java
@@ -21,6 +21,13 @@ public class Color {
   public final double blue;
   private String m_name;
 
+  /** Constructs a default color (black). */
+  public Color() {
+    red = 0.0;
+    green = 0.0;
+    blue = 0.0;
+  }
+
   /**
    * Constructs a Color from doubles.
    *
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
index e9e0e8880b3..5d916e1941a 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/util/Color8Bit.java
@@ -14,6 +14,13 @@ public class Color8Bit {
   public final int green;
   public final int blue;
 
+  /** Constructs a default color (black). */
+  public Color8Bit() {
+    red = 0;
+    green = 0;
+    blue = 0;
+  }
+
   /**
    * Constructs a Color8Bit.
    *
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
index 42abf020d76..499ecbde80c 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/Color8BitTest.java
@@ -4,21 +4,62 @@
 
 package edu.wpi.first.wpilibj.util;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 import org.junit.jupiter.api.Test;
 
 class Color8BitTest {
   @Test
-  void testConstructDefault() {}
+  void testConstructDefault() {
+    var color = new Color8Bit();
+
+    assertEquals(0, color.red);
+    assertEquals(0, color.green);
+    assertEquals(0, color.blue);
+  }
 
   @Test
-  void testConstructFromInts() {}
+  void testConstructFromInts() {
+    var color = new Color8Bit(255, 128, 64);
+
+    assertEquals(255, color.red);
+    assertEquals(128, color.green);
+    assertEquals(64, color.blue);
+  }
 
   @Test
-  void testConstructFromColor() {}
+  void testConstructFromColor() {
+    var color = new Color8Bit(new Color(255, 128, 64));
+
+    assertEquals(255, color.red);
+    assertEquals(128, color.green);
+    assertEquals(64, color.blue);
+  }
 
   @Test
-  void testConstructFromHexString() {}
+  void testConstructFromHexString() {
+    var color = new Color8Bit("#FF8040");
+
+    assertEquals(255, color.red);
+    assertEquals(128, color.green);
+    assertEquals(64, color.blue);
+
+    // No leading #
+    assertThrows(IllegalArgumentException.class, () -> new Color8Bit("112233"));
+
+    // Too long
+    assertThrows(IllegalArgumentException.class, () -> new Color8Bit("#11223344"));
+
+    // Invalid hex characters
+    assertThrows(IllegalArgumentException.class, () -> new Color8Bit("#$$$$$$"));
+  }
 
   @Test
-  void testToHexString() {}
+  void testToHexString() {
+    var color = new Color8Bit(255, 128, 64);
+
+    assertEquals("#FF8040", color.toHexString());
+    assertEquals("#FF8040", color.toString());
+  }
 }
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
index fdd8fbd6870..c6af4e35c21 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java
@@ -4,24 +4,71 @@
 
 package edu.wpi.first.wpilibj.util;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 import org.junit.jupiter.api.Test;
 
 class ColorTest {
   @Test
-  void testConstructDefault() {}
+  void testConstructDefault() {
+    var color = new Color();
+
+    assertEquals(0.0, color.red);
+    assertEquals(0.0, color.green);
+    assertEquals(0.0, color.blue);
+  }
 
   @Test
-  void testConstructFromDoubles() {}
+  void testConstructFromDoubles() {
+    var color = new Color(1.0, 0.5, 0.25);
+
+    assertEquals(1.0, color.red, 1e-2);
+    assertEquals(0.5, color.green, 1e-2);
+    assertEquals(0.25, color.blue, 1e-2);
+  }
 
   @Test
-  void testConstructFromInts() {}
+  void testConstructFromInts() {
+    var color = new Color(255, 128, 64);
+
+    assertEquals(1.0, color.red, 1e-2);
+    assertEquals(0.5, color.green, 1e-2);
+    assertEquals(0.25, color.blue, 1e-2);
+  }
 
   @Test
-  void testConstructFromHexString() {}
+  void testConstructFromHexString() {
+    var color = new Color("#FF8040");
+
+    assertEquals(1.0, color.red, 1e-2);
+    assertEquals(0.5, color.green, 1e-2);
+    assertEquals(0.25, color.blue, 1e-2);
+
+    // No leading #
+    assertThrows(IllegalArgumentException.class, () -> new Color("112233"));
+
+    // Too long
+    assertThrows(IllegalArgumentException.class, () -> new Color("#11223344"));
+
+    // Invalid hex characters
+    assertThrows(IllegalArgumentException.class, () -> new Color("#$$$$$$"));
+  }
 
   @Test
-  void testFromHSV() {}
+  void testFromHSV() {
+    var color = Color.fromHSV(90, 128, 64);
+
+    assertEquals(0.125732421875, color.red);
+    assertEquals(0.251220703125, color.green);
+    assertEquals(0.251220703125, color.blue);
+  }
 
   @Test
-  void testToHexString() {}
+  void testToHexString() {
+    var color = new Color(255, 128, 64);
+
+    assertEquals("#FF8040", color.toHexString());
+    assertEquals("#FF8040", color.toString());
+  }
 }

From f2e501995244377109b5bb1a8e26c967c69c0d99 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Fri, 1 Dec 2023 09:41:16 -0800
Subject: [PATCH 10/10] Move non-constexpr function to .cpp file

---
 wpilibc/src/main/native/cpp/util/Color.cpp          | 13 +++++++++++++
 wpilibc/src/main/native/cpp/util/Color8Bit.cpp      | 11 +++++++++++
 wpilibc/src/main/native/include/frc/util/Color.h    |  6 +-----
 .../src/main/native/include/frc/util/Color8Bit.h    |  4 +---
 4 files changed, 26 insertions(+), 8 deletions(-)
 create mode 100644 wpilibc/src/main/native/cpp/util/Color.cpp
 create mode 100644 wpilibc/src/main/native/cpp/util/Color8Bit.cpp

diff --git a/wpilibc/src/main/native/cpp/util/Color.cpp b/wpilibc/src/main/native/cpp/util/Color.cpp
new file mode 100644
index 00000000000..6923c9cbec1
--- /dev/null
+++ b/wpilibc/src/main/native/cpp/util/Color.cpp
@@ -0,0 +1,13 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/util/Color.h"
+
+using namespace frc;
+
+std::string Color::HexString() const {
+  return fmt::format("#{:02X}{:02X}{:02X}", static_cast<int>(255.0 * red),
+                     static_cast<int>(255.0 * green),
+                     static_cast<int>(255.0 * blue));
+}
diff --git a/wpilibc/src/main/native/cpp/util/Color8Bit.cpp b/wpilibc/src/main/native/cpp/util/Color8Bit.cpp
new file mode 100644
index 00000000000..e8e46567d70
--- /dev/null
+++ b/wpilibc/src/main/native/cpp/util/Color8Bit.cpp
@@ -0,0 +1,11 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/util/Color8Bit.h"
+
+using namespace frc;
+
+std::string Color8Bit::HexString() const {
+  return fmt::format("#{:02X}{:02X}{:02X}", red, green, blue);
+}
diff --git a/wpilibc/src/main/native/include/frc/util/Color.h b/wpilibc/src/main/native/include/frc/util/Color.h
index 3e4567373d7..b5855e23ce8 100644
--- a/wpilibc/src/main/native/include/frc/util/Color.h
+++ b/wpilibc/src/main/native/include/frc/util/Color.h
@@ -851,11 +851,7 @@ class Color {
    *
    * @return a string of the format <tt>\#RRGGBB</tt>
    */
-  std::string HexString() const {
-    return fmt::format("#{:02X}{:02X}{:02X}", static_cast<int>(255.0 * red),
-                       static_cast<int>(255.0 * green),
-                       static_cast<int>(255.0 * blue));
-  }
+  std::string HexString() const;
 
   double red = 0.0;
   double green = 0.0;
diff --git a/wpilibc/src/main/native/include/frc/util/Color8Bit.h b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
index 559559bcd14..77bdc9f0ee5 100644
--- a/wpilibc/src/main/native/include/frc/util/Color8Bit.h
+++ b/wpilibc/src/main/native/include/frc/util/Color8Bit.h
@@ -107,9 +107,7 @@ class Color8Bit {
    *
    * @return a string of the format <tt>\#RRGGBB</tt>
    */
-  std::string HexString() const {
-    return fmt::format("#{:02X}{:02X}{:02X}", red, green, blue);
-  }
+  std::string HexString() const;
 
   int red = 0;
   int green = 0;