Uses the inverted color for a dyed sign's highlighting color

src/main/java/net/knarcraft/stargate/container/SignData.java

@@ -1,7 +1,7 @@
 package net.knarcraft.stargate.container;
 
+import net.knarcraft.stargate.utility.ColorHelper;
 import net.md_5.bungee.api.ChatColor;
-import org.bukkit.Color;
 import org.bukkit.DyeColor;
 import org.bukkit.block.Sign;
 
@@ -45,8 +45,7 @@ public class SignData {
      */
     public ChatColor getMainSignColor() {
         if (dyedColor != DyeColor.BLACK) {
-            Color color = dyedColor.getColor();
-            return ChatColor.of(String.format("#%02X%02X%02X", color.getRed(), color.getGreen(), color.getBlue()));
+            return ColorHelper.fromColor(dyedColor.getColor());
         } else {
             return mainSignColor;
         }
@@ -58,7 +57,11 @@ public class SignData {
      * @return <p>The highlighting color of the sign</p>
      */
     public ChatColor getHighlightSignColor() {
-        return highlightSignColor;
+        if (dyedColor != DyeColor.BLACK) {
+            return ColorHelper.fromColor(ColorHelper.invert(dyedColor.getColor()));
+        } else {
+            return highlightSignColor;
+        }
     }
 
 }

src/main/java/net/knarcraft/stargate/portal/PortalSignDrawer.java

@@ -11,8 +11,8 @@ import org.bukkit.block.BlockState;
 import org.bukkit.block.Sign;
 
 import java.util.Map;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
+
+import static net.knarcraft.stargate.utility.ColorHelper.translateAllColorCodes;
 
 /**
  * The portal sign drawer draws the sing of a given portal
@@ -345,22 +345,6 @@ public class PortalSignDrawer {
         Stargate.logInfo(String.format("Gate layout on line %d does not exist [%s]", lineIndex, gateName));
     }
 
-    /**
-     * Translates all found color codes to formatting in a string
-     *
-     * @param message <p>The string to search for color codes</p>
-     * @return <p>The message with color codes translated</p>
-     */
-    public static String translateAllColorCodes(String message) {
-        message = ChatColor.translateAlternateColorCodes('&', message);
-        Pattern pattern = Pattern.compile("(#[a-fA-F0-9]{6})");
-        Matcher matcher = pattern.matcher(message);
-        while (matcher.find()) {
-            message = message.replace(matcher.group(), "" + ChatColor.of(matcher.group()));
-        }
-        return message;
-    }
-
     /**
      * Gets the main color to use for the given sign type
      *

src/main/java/net/knarcraft/stargate/utility/ColorHelper.java

@@ -0,0 +1,47 @@
+package net.knarcraft.stargate.utility;
+
+import net.md_5.bungee.api.ChatColor;
+import org.bukkit.Color;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ColorHelper {
+
+    /**
+     * Inverts the given color
+     *
+     * @param color <p>The color to invert</p>
+     * @return <p>The inverted color</p>
+     */
+    public static Color invert(Color color) {
+        return color.setRed(255 - color.getRed()).setGreen(255 - color.getGreen()).setBlue(255 - color.getBlue());
+    }
+
+    /**
+     * Gets the chat color corresponding to the given color
+     *
+     * @param color <p>The color to convert into a chat color</p>
+     * @return <p>The resulting chat color</p>
+     */
+    public static ChatColor fromColor(Color color) {
+        return ChatColor.of(String.format("#%02X%02X%02X", color.getRed(), color.getGreen(), color.getBlue()));
+    }
+
+    /**
+     * Translates all found color codes to formatting in a string
+     *
+     * @param message <p>The string to search for color codes</p>
+     * @return <p>The message with color codes translated</p>
+     */
+    public static String translateAllColorCodes(String message) {
+        message = ChatColor.translateAlternateColorCodes('&', message);
+        Pattern pattern = Pattern.compile("(#[a-fA-F0-9]{6})");
+        Matcher matcher = pattern.matcher(message);
+        while (matcher.find()) {
+            message = message.replace(matcher.group(), "" + ChatColor.of(matcher.group()));
+        }
+        return message;
+    }
+
+}