[wpilib] Improve Color.toString (#4450)

wpilibc/src/main/native/include/frc/smartdashboard/Mechanism2d.h

@@ -79,7 +79,7 @@ class Mechanism2d : public nt::NTSendable,
  private:
   double m_width;
   double m_height;
-  char m_color[10];
+  std::string m_color;
   mutable wpi::mutex m_mutex;
   std::shared_ptr<nt::NetworkTable> m_table;
   wpi::StringMap<std::unique_ptr<MechanismRoot2d>> m_roots;

wpilibc/src/main/native/include/frc/util/Color.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <algorithm>
+#include <string>
 
 namespace frc {
 
@@ -808,6 +809,13 @@ class Color {
     }
   }
 
+  /**
+   * Return this color represented as a hex string.
+   *
+   * @return a string of the format <tt>\#RRGGBB</tt>
+   */
+  std::string HexString() const;
+
   double red = 0.0;
   double green = 0.0;
   double blue = 0.0;

wpilibc/src/main/native/include/frc/util/Color8Bit.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <algorithm>
+#include <string>
 
 #include "Color.h"
 
@@ -43,6 +44,13 @@ class Color8Bit {
     return Color(red / 255.0, green / 255.0, blue / 255.0);
   }
 
+  /**
+   * Return this color represented as a hex string.
+   *
+   * @return a string of the format <tt>\#RRGGBB</tt>
+   */
+  std::string HexString() const;
+
   int red = 0;
   int green = 0;
   int blue = 0;