Add color utility class

In addition to creating `colorTag`, `prependColorTag`, and
`wrapWithColorTag` functions, this commit moves
`SwingUtil::toHexColor` and `SwingUtil::colorLerp` to this new class.

runelite-client/src/test/java/net/runelite/client/util/ColorUtilTest.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2018, Jordan Atwood <jordan.atwood423@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.runelite.client.util;
+
+import java.awt.Color;
+import java.util.HashMap;
+import java.util.Map;
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class ColorUtilTest
+{
+	private static final Map<Color, String> COLOR_HEXSTRING_MAP = new HashMap<Color, String>()
+	{{
+		put(Color.BLACK, "000000");
+		put(new Color(0x1), "000001");
+		put(new Color(0x100000), "100000");
+		put(Color.RED, "ff0000");
+		put(Color.GREEN, "00ff00");
+		put(Color.BLUE, "0000ff");
+		put(new Color(0xA1B2C3), "a1b2c3");
+		put(Color.WHITE, "ffffff");
+	}};
+
+	@Test
+	public void colorTag()
+	{
+		COLOR_HEXSTRING_MAP.forEach((color, hex) -> {
+			assertEquals("<col=" + hex + ">", ColorUtil.colorTag(color));
+		});
+	}
+
+	@Test
+	public void prependColorTag()
+	{
+		COLOR_HEXSTRING_MAP.forEach((color, hex) -> {
+			assertEquals("<col=" + hex + ">test", ColorUtil.prependColorTag("test", color));
+			assertEquals("<col=" + hex + ">", ColorUtil.prependColorTag("", color));
+		});
+
+		assertEquals("<col=ff0000>94<col=ffffff>/99", ColorUtil.prependColorTag("94" + ColorUtil.prependColorTag("/99", Color.WHITE), Color.RED));
+	}
+
+	@Test
+	public void wrapWithColorTag()
+	{
+		COLOR_HEXSTRING_MAP.forEach((color, hex) -> {
+			assertEquals("<col=" + hex + ">test</col>", ColorUtil.wrapWithColorTag("test", color));
+			assertEquals("<col=" + hex + "></col>", ColorUtil.wrapWithColorTag("", color));
+		});
+	}
+
+	@Test
+	public void toHexColor()
+	{
+		COLOR_HEXSTRING_MAP.forEach((color, hex) -> {
+			assertEquals("#" + hex, ColorUtil.toHexColor(color));
+		});
+	}
+
+	@Test
+	public void colorLerp()
+	{
+		assertEquals(Color.WHITE, ColorUtil.colorLerp(Color.WHITE, Color.WHITE, 0.9));
+		assertEquals(new Color(128, 128, 128), ColorUtil.colorLerp(Color.BLACK, Color.WHITE, 0.5));
+		assertEquals(Color.BLACK, ColorUtil.colorLerp(Color.BLACK, Color.CYAN, 0));
+		assertEquals(Color.CYAN, ColorUtil.colorLerp(Color.BLACK, Color.CYAN, 1));
+	}
+
+	@Test
+	public void colorToHexCode()
+	{
+		COLOR_HEXSTRING_MAP.forEach((color, hex) -> {
+			assertEquals(hex, ColorUtil.colorToHexCode(color));
+		});
+	}
+}