deadzone.js

var game = new Phaser.Game(800, 600, Phaser.CANVAS, 'phaser-example', { preload: preload, create: create, update: update, render: render });

function preload() {

    game.load.image('background','assets/tests/debug-grid-1920x1920.png');
    game.load.image('player','assets/sprites/phaser-dude.png');

}

var player;
var cursors;

function create() {

    game.add.tileSprite(0, 0, 1920, 1920, 'background');

    game.world.setBounds(0, 0, 1920, 1920);

    game.physics.startSystem(Phaser.Physics.P2JS);

    player = game.add.sprite(game.world.centerX, game.world.centerY, 'player');

    game.physics.p2.enable(player);

    cursors = game.input.keyboard.createCursorKeys();

    game.camera.follow(player);

    //  The deadzone is a Rectangle that defines the limits at which the camera will start to scroll
    //  It does NOT keep the target sprite within the rectangle, all it does is control the boundary
    //  at which the camera will start to move. So when the sprite hits the edge, the camera scrolls
    //  (until it reaches an edge of the world)
    game.camera.deadzone = new Phaser.Rectangle(100, 100, 600, 400);

}

function update() {

    player.body.setZeroVelocity();

    if (cursors.up.isDown)
    {
        player.body.moveUp(300)
    }
    else if (cursors.down.isDown)
    {
        player.body.moveDown(300);
    }

    if (cursors.left.isDown)
    {
        player.body.velocity.x = -300;
    }
    else if (cursors.right.isDown)
    {
        player.body.moveRight(300);
    }

}

function render() {

    var zone = game.camera.deadzone;

    game.context.fillStyle = 'rgba(255,0,0,0.6)';
    game.context.fillRect(zone.x, zone.y, zone.width, zone.height);

    game.debug.cameraInfo(game.camera, 32, 32);
    game.debug.spriteCoords(player, 32, 500);

}