Implement PlayerViewDistanceChangeEvent (#4749)

closes #4550

src/event/player/PlayerViewDistanceChangeEvent.php

@@ -0,0 +1,55 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\event\player;
+
+use pocketmine\player\Player;
+
+/**
+ * Called when a player requests a different viewing distance than the current one.
+ */
+class PlayerViewDistanceChangeEvent extends PlayerEvent{
+	protected int $newDistance;
+	protected int $oldDistance;
+
+	public function __construct(Player $player, int $oldDistance, int $newDistance){
+		$this->player = $player;
+		$this->oldDistance = $oldDistance;
+		$this->newDistance = $newDistance;
+	}
+
+	/**
+	 * Returns the new view radius, measured in chunks.
+	 */
+	public function getNewDistance() : int{
+		return $this->newDistance;
+	}
+
+	/**
+	 * Returns the old view radius, measured in chunks.
+	 * A value of -1 means that the player has just connected and did not have a view distance before this event.
+	 */
+	public function getOldDistance() : int{
+		return $this->oldDistance;
+	}
+}