rl-client: add ColorUtil/OverlayUtil

runelite-client/src/main/java/com/openosrs/client/util/ColorUtil.java

@@ -0,0 +1,34 @@
+package com.openosrs.client.util;
+
+import java.awt.Color;
+
+public class ColorUtil extends net.runelite.client.util.ColorUtil
+{
+	/**
+	 * Modifies the alpha component on a Color
+	 *
+	 * @param color The color to set the alpha value on
+	 * @param alpha The alpha value to set on the color
+	 * @return color
+	 */
+	public static int setAlphaComponent(Color color, int alpha)
+	{
+		return setAlphaComponent(color.getRGB(), alpha);
+	}
+
+	/**
+	 * Modifies the alpha component on a Color
+	 *
+	 * @param color The color to set the alpha value on
+	 * @param alpha The alpha value to set on the color
+	 * @return color
+	 */
+	public static int setAlphaComponent(int color, int alpha)
+	{
+		if (alpha < 0 || alpha > 255)
+		{
+			throw new IllegalArgumentException("alpha must be between 0 and 255.");
+		}
+		return (color & 0x00ffffff) | (alpha << 24);
+	}
+}