It ALL works!

The single map mode has best performance
Some latency, fix by only using Java

plugin.yml

@@ -2,3 +2,6 @@ name: AudioSpectrum
 main: io.github.norbipeti.audiospectrum.PluginMain
 version: 4.0
 commands:
+ barcount:
+     usage: Please give a number between 0 and 16.
+ singlemap:

src/io/github/norbipeti/audiospectrum/BarsRenderer.java

@@ -1,27 +1,55 @@
 package io.github.norbipeti.audiospectrum;
 
+import java.awt.Color;
+
 import org.bukkit.entity.Player;
 import org.bukkit.map.*;
 
-public class BarsRenderer extends MapRenderer
+public class BarsRenderer extends BarsRendererBase
 {
-	private int[] bars;
+	private boolean single = false;
 
 	public BarsRenderer(int[] bars)
 	{
-		this.bars = bars;
+		super(bars);
 	}
 
 	@SuppressWarnings("deprecation")
 	@Override
 	public void render(MapView mv, MapCanvas mc, Player pl)
-	{ //Width: 16, empty space: 16, count per map: 8
+	{ //Width: 8, empty space: 8, count per map: 8
+			//if (firstrender ? !(firstrender = !firstrender) : firstrender)
+		if (firstrender < 4 ? firstrender++ < 4 : false) //Only increment if true
+			for (int i = 0; i < 128; i++)
+				for (int j = 0; j < 128; j++)
+					mc.setPixel(i, j, MapPalette.matchColor(Color.black));
+		if (single)
+		{
+			if (mv.getId() != 0)
+				return;
+			for (int i = 0; i < 16 && i < count; i++)
+				for (int j = 0; j < 128; j++)
+					for (int k = 0; k < 4; k++)
+						mc.setPixel(i * 8 + k, 128 - j, j < bars[i] / 2 ? MapPalette.matchColor(j, 255 - j * 2, 0)
+								: MapPalette.matchColor(Color.BLACK));
+			return;
+		}
 		int offsetx = mv.getId() % 2 * 8, offsety = mv.getId() < 2 ? -128 : 0;
 		//System.out.println("OX: " + offsetx + " OY: " + offsety + " ID: " + mv.getId());
-		for (int i = 0; i < 8; i++)
+		for (int i = 0; i < 8 && i < count - offsetx; i++)
 			for (int j = 0; j < 128; j++)
-				for (int k = 0; k < 16; k++)
-					mc.setPixel(i * 32 + k, 128 - j, j < bars[offsetx + i] + offsety
-							? MapPalette.matchColor(255 - j + offsety, j - offsety, 0) : 0); //TODO: 0 is transparent
-	} //TODO: Render areas inbetween black
+				for (int k = 0; k < 8; k++)
+					mc.setPixel(i * 16 + k, 128 - j,
+							j < bars[offsetx + i] + offsety ? MapPalette.matchColor(j - offsety, 255 - j + offsety, 0)
+									: MapPalette.matchColor(Color.BLACK));
+	}
+
+	/**
+	 * Sets whether to use a single map or 4
+	 */
+	public boolean toggleSingle()
+	{
+		firstrender = 0;
+		return this.single = !single;
+	}
 }

src/io/github/norbipeti/audiospectrum/BarsRendererBase.java

@@ -0,0 +1,23 @@
+package io.github.norbipeti.audiospectrum;
+
+import org.bukkit.map.MapRenderer;
+
+public abstract class BarsRendererBase extends MapRenderer
+{
+	protected int[] bars;
+	protected byte firstrender = 0;
+	protected byte count = 16;
+
+	public BarsRendererBase(int[] bars)
+	{
+		this.bars = bars;
+	}
+
+	public byte setBarCount(byte count)
+	{
+		firstrender = 0;
+		if (count >= 0 && count <= 16)
+			this.count = count;
+		return this.count;
+	}
+}

src/io/github/norbipeti/audiospectrum/PluginMain.java

@@ -4,9 +4,9 @@ import java.io.IOException;
 import java.net.DatagramPacket;
 import java.net.DatagramSocket;
 import java.net.InetAddress;
-import java.util.Arrays;
-
 import org.bukkit.Bukkit;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
 import org.bukkit.map.MapView;
 import org.bukkit.plugin.java.JavaPlugin;
 
@@ -15,13 +15,14 @@ public class PluginMain extends JavaPlugin
 	private Thread thread;
 	private boolean running = false;
 	private volatile int[] bars = new int[16];
+	private BarsRenderer br;
 
 	// Fired when plugin is first enabled
 	@SuppressWarnings("deprecation")
 	@Override
 	public void onEnable()
 	{
-		BarsRenderer br = new BarsRenderer(bars);
+		br = new BarsRenderer(bars);
 		for (short i = 0; i < 4; i++)
 		{
 			MapView map = Bukkit.getMap(i);
@@ -32,6 +33,7 @@ public class PluginMain extends JavaPlugin
 		}
 		thread = new Thread()
 		{
+			@Override
 			public void run()
 			{
 				PluginMain.this.run(5896);
@@ -48,7 +50,7 @@ public class PluginMain extends JavaPlugin
 		running = false;
 	}
 
-	private volatile byte[] packet = new byte[2];
+	private volatile byte[] packet = new byte[16];
 
 	public void run(int port)
 	{
@@ -76,4 +78,32 @@ public class PluginMain extends JavaPlugin
 			serverSocket.close();
 		}
 	}
+
+	@Override
+	public boolean onCommand(CommandSender sender, Command command, String label, String[] args)
+	{
+		if (command.getName().equalsIgnoreCase("barcount"))
+		{
+			if (args.length < 1)
+				return false;
+			try
+			{
+				byte c = Byte.parseByte(args[0]);
+				sender.sendMessage("Bar count set to " + br.setBarCount(c));
+				return true;
+
+			} catch (Exception e)
+			{
+				return false;
+			}
+		} else if (command.getName().equalsIgnoreCase("singlemap"))
+		{
+			sender.sendMessage("Single map toggled, now " + br.toggleSingle());
+			return true;
+		} else
+		{
+			sender.sendMessage("Command not implemented!");
+			return true;
+		}
+	}
 }