Index: ps/trunk/binaries/data/mods/public/gui/session/DiplomacyColors.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/DiplomacyColors.js	(nonexistent)
+++ ps/trunk/binaries/data/mods/public/gui/session/DiplomacyColors.js	(revision 23066)
@@ -0,0 +1,101 @@
+/**
+ * This class determines the player colors to be displayed.
+ * If diplomacy color mode is disabled, it picks the player color chosen by the map or the players.
+ * If diplomacy color mode is enabled, it choses the player chosen color based on diplomatic stance.
+ * Observers that didn't chose a specific player perspective see each team in one representative color.
+ */
+class DiplomacyColors
+{
+	constructor()
+	{
+		this.enabled = false;
+
+		// The array of displayed player colors (either the diplomacy color or regular color for each player).
+		this.displayedPlayerColors = undefined;
+	}
+
+	onPlayerInit()
+	{
+		this.computeTeamColors();
+	}
+
+	onDiplomacyChange()
+	{
+		if (this.enabled)
+			this.updateDisplayedPlayerColors();
+	}
+
+	onCeasefireEnded()
+	{
+		if (this.enabled)
+			this.updateDisplayedPlayerColors();
+	}
+
+	isEnabled()
+	{
+		return this.enabled;
+	}
+
+	toggle()
+	{
+		this.enabled = !this.enabled;
+		this.updateDisplayedPlayerColors();
+	}
+
+	getPlayerColor(playerID, alpha)
+	{
+		return rgbToGuiColor(this.displayedPlayerColors[playerID], alpha);
+	}
+
+	/**
+	 * Updates the displayed colors of players in the simulation and GUI.
+	 */
+	updateDisplayedPlayerColors()
+	{
+		this.computeTeamColors();
+
+		Engine.GuiInterfaceCall("UpdateDisplayedPlayerColors", {
+			"displayedPlayerColors": this.displayedPlayerColors,
+			"displayDiplomacyColors": this.enabled,
+			"showAllStatusBars": g_ShowAllStatusBars,
+			"selected": g_Selection.toList()
+		});
+
+		updateGUIObjects();
+	}
+
+	computeTeamColors()
+	{
+		if (!this.enabled)
+		{
+			this.displayedPlayerColors = g_Players.map(player => player.color);
+			return;
+		}
+
+		let teamRepresentatives = {};
+		for (let i = 1; i < g_Players.length; ++i)
+			if (g_ViewedPlayer <= 0)
+			{
+				// Observers and gaia see team colors
+				let team = g_Players[i].team;
+				this.displayedPlayerColors[i] = g_Players[teamRepresentatives[team] || i].color;
+				if (team != -1 && !teamRepresentatives[team])
+					teamRepresentatives[team] = i;
+			}
+			else
+				// Players see colors depending on diplomacy
+				this.displayedPlayerColors[i] =
+					g_ViewedPlayer == i ? this.getDiplomacyColor("self") :
+					g_Players[g_ViewedPlayer].isAlly[i] ? this.getDiplomacyColor("ally") :
+					g_Players[g_ViewedPlayer].isNeutral[i] ? this.getDiplomacyColor("neutral") :
+					this.getDiplomacyColor("enemy");
+
+		this.displayedPlayerColors[0] = g_Players[0].color;
+	}
+
+	getDiplomacyColor(stance)
+	{
+		return guiToRgbColor(Engine.ConfigDB_GetValue("user", "gui.session.diplomacycolors." + stance)) ||
+		       guiToRgbColor(Engine.ConfigDB_GetValue("default", "gui.session.diplomacycolors." + stance));
+	}
+}