Give your HTML5 games a “full screen” option and manage game scaling and resizing in a couple of lines of code thanks to Phaser 3 version 3.16

There are great news for all HTML5 game developers and Phaser enthusiasts: the long awaited 3.16 version has been released and brings a complete scale manager and also a full screen feature. If you used to code with Phaser 2, probably the feature you missed the most once you moved on to Phaser 3 was the scale manager. You had to move and resize the canvas on your own, using your JavaScript and CSS to sort the things out. For this reason I published the post How to scale your HTML5 games if your framework does not feature a scale manager – or if you do not use any framework. Finally, the scale manager is back in Phaser 3, and it also comes with a full screen feature. Look at the endless runner game I am blogging about during these days:
Click or tap to jump or double jump. Once the focus is on the iframe hosting the game, pressing SPACEBAR will make the game run in full screen. What changed since previous version? First, the code in the page hosting the game has no CSS, switching from this code:
<!DOCTYPE html&gt;
<html&gt;
	<head&gt;
        <style type = "text/css"&gt;
            body{
                background: #000000;
                padding: 0px;
                margin: 0px;
            }
            canvas{
                display:block;
                margin: 0;
                position: absolute;
                top: 50%;
                left: 50%;
                transform: translate(-50%, -50%);
            }
        </style&gt;
        <script src = "phaser.min.js"&gt;</script&gt;
        <script src = "game.js"&gt;</script&gt;
    </head&gt;
	<body&gt;
	</body&gt;
</html&gt;
To this code:

<!DOCTYPE html&gt;
<html&gt;
	<head&gt;
        <style type = "text/css"&gt;
            body{
                background: #000000;
                padding: 0px;
                margin: 0px;
            }
        </style&gt;
        <script src = "phaser.min.js"&gt;</script&gt;
        <script src = "game.js"&gt;</script&gt;
    </head&gt;
	<body&gt;
        <div id = "thegame"&gt;</div&gt;
	</body&gt;
</html&gt;
It’s much cleaner now, with no CSS to center the canvas on the browser window. I just added a div where to place the game itself What about the game script? When you define the object with game configuration, you will be able to define the scale mode, like in this case:
scale: {
    mode: Phaser.Scale.FIT,
    autoCenter: Phaser.Scale.CENTER_BOTH,
    parent: "thegame",
    width: 1334,
    height: 750
}
In the previous code I am saying I want the game to fit the largest area of the browser while keeping the whole content visible, centering the canvas both horizontally and vertically, using the canvas whose id is thegame, with a 1334×750 size. Full screen management is even easier:
if(!this.scale.isFullscreen){
    this.scale.startFullscreen();
}
Look at the whole code in action, where everything is handled by Phaser:
let game;

// global game options
let gameOptions = {

    // platform speed range, in pixels per second
    platformSpeedRange: [300, 300],

    // mountain speed, in pixels per second
    mountainSpeed: 80,

    // spawn range, how far should be the rightmost platform from the right edge
    // before next platform spawns, in pixels
    spawnRange: [80, 300],

    // platform width range, in pixels
    platformSizeRange: [90, 300],

    // a height range between rightmost platform and next platform to be spawned
    platformHeightRange: [-5, 5],

    // a scale to be multiplied by platformHeightRange
    platformHeighScale: 20,

    // platform max and min height, as screen height ratio
    platformVerticalLimit: [0.4, 0.8],

    // player gravity
    playerGravity: 900,

    // player jump force
    jumpForce: 400,

    // player starting X position
    playerStartPosition: 200,

    // consecutive jumps allowed
    jumps: 2,

    // % of probability a coin appears on the platform
    coinPercent: 25,

    // % of probability a fire appears on the platform
    firePercent: 25
}

window.onload = function() {

    // object containing configuration options
    let gameConfig = {
        type: Phaser.AUTO,
        scale: {
            mode: Phaser.Scale.FIT,
            autoCenter: Phaser.Scale.CENTER_BOTH,
            parent: "thegame",
            width: 1334,
            height: 750
        },
        scene: [preloadGame, playGame],
        backgroundColor: 0x0c88c7,

        // physics settings
        physics: {
            default: "arcade"
        }
    }
    game = new Phaser.Game(gameConfig);
    window.focus();
}

// preloadGame scene
class preloadGame extends Phaser.Scene{
    constructor(){
        super("PreloadGame");
    }
    preload(){
        this.load.image("platform", "platform.png");

        // player is a sprite sheet made by 24x48 pixels
        this.load.spritesheet("player", "player.png", {
            frameWidth: 24,
            frameHeight: 48
        });

        // the coin is a sprite sheet made by 20x20 pixels
        this.load.spritesheet("coin", "coin.png", {
            frameWidth: 20,
            frameHeight: 20
        });

        // the firecamp is a sprite sheet made by 32x58 pixels
        this.load.spritesheet("fire", "fire.png", {
            frameWidth: 40,
            frameHeight: 70
        });

        // mountains are a sprite sheet made by 512x512 pixels
        this.load.spritesheet("mountain", "mountain.png", {
            frameWidth: 512,
            frameHeight: 512
        });
    }
    create(){

        // setting player animation
        this.anims.create({
            key: "run",
            frames: this.anims.generateFrameNumbers("player", {
                start: 0,
                end: 1
            }),
            frameRate: 8,
            repeat: -1
        });

        // setting coin animation
        this.anims.create({
            key: "rotate",
            frames: this.anims.generateFrameNumbers("coin", {
                start: 0,
                end: 5
            }),
            frameRate: 15,
            yoyo: true,
            repeat: -1
        });

        // setting fire animation
        this.anims.create({
            key: "burn",
            frames: this.anims.generateFrameNumbers("fire", {
                start: 0,
                end: 4
            }),
            frameRate: 15,
            repeat: -1
        });

        this.scene.start("PlayGame");
    }
}

// playGame scene
class playGame extends Phaser.Scene{
    constructor(){
        super("PlayGame");
    }
    create(){

        // group with all active mountains.
        this.mountainGroup = this.add.group();

        // group with all active platforms.
        this.platformGroup = this.add.group({

            // once a platform is removed, it's added to the pool
            removeCallback: function(platform){
                platform.scene.platformPool.add(platform)
            }
        });

        // platform pool
        this.platformPool = this.add.group({

            // once a platform is removed from the pool, it's added to the active platforms group
            removeCallback: function(platform){
                platform.scene.platformGroup.add(platform)
            }
        });

        // group with all active coins.
        this.coinGroup = this.add.group({

            // once a coin is removed, it's added to the pool
            removeCallback: function(coin){
                coin.scene.coinPool.add(coin)
            }
        });

        // coin pool
        this.coinPool = this.add.group({

            // once a coin is removed from the pool, it's added to the active coins group
            removeCallback: function(coin){
                coin.scene.coinGroup.add(coin)
            }
        });

        // group with all active firecamps.
        this.fireGroup = this.add.group({

            // once a firecamp is removed, it's added to the pool
            removeCallback: function(fire){
                fire.scene.firePool.add(fire)
            }
        });

        // fire pool
        this.firePool = this.add.group({

            // once a fire is removed from the pool, it's added to the active fire group
            removeCallback: function(fire){
                fire.scene.fireGroup.add(fire)
            }
        });

        // adding a mountain
        this.addMountains()

        // keeping track of added platforms
        this.addedPlatforms = 0;

        // number of consecutive jumps made by the player so far
        this.playerJumps = 0;

        // adding a platform to the game, the arguments are platform width, x position and y position
        this.addPlatform(game.config.width, game.config.width / 2, game.config.height * gameOptions.platformVerticalLimit[1]);

        // adding the player;
        this.player = this.physics.add.sprite(gameOptions.playerStartPosition, game.config.height * 0.7, "player");
        this.player.setGravityY(gameOptions.playerGravity);
        this.player.setDepth(2);

        // the player is not dying
        this.dying = false;

        // setting collisions between the player and the platform group
        this.platformCollider = this.physics.add.collider(this.player, this.platformGroup, function(){

            // play "run" animation if the player is on a platform
            if(!this.player.anims.isPlaying){
                this.player.anims.play("run");
            }
        }, null, this);

        // setting collisions between the player and the coin group
        this.physics.add.overlap(this.player, this.coinGroup, function(player, coin){

            this.tweens.add({
                targets: coin,
                y: coin.y - 100,
                alpha: 0,
                duration: 800,
                ease: "Cubic.easeOut",
                callbackScope: this,
                onComplete: function(){
                    this.coinGroup.killAndHide(coin);
                    this.coinGroup.remove(coin);
                }
            });

        }, null, this);

        // setting collisions between the player and the fire group
        this.physics.add.overlap(this.player, this.fireGroup, function(player, fire){

            this.dying = true;
            this.player.anims.stop();
            this.player.setFrame(2);
            this.player.body.setVelocityY(-200);
            this.physics.world.removeCollider(this.platformCollider);

        }, null, this);

        // checking for input
        this.input.on("pointerdown", this.jump, this);

        this.add.text(20, 0, "Press SPACEBAR to enter fullscreen", {
            fontFamily: "Arial",
            fontSize: 64,
            color: "#ffffff"
        });

        this.input.keyboard.on("keydown_SPACE", function(){
            if(!this.scale.isFullscreen){
                this.scale.startFullscreen();
            }
        }, this);
    }

    // adding mountains
    addMountains(){
        let rightmostMountain = this.getRightmostMountain();
        if(rightmostMountain < game.config.width * 2){
            let mountain = this.physics.add.sprite(rightmostMountain + Phaser.Math.Between(100, 350), game.config.height + Phaser.Math.Between(0, 100), "mountain");
            mountain.setOrigin(0.5, 1);
            mountain.body.setVelocityX(gameOptions.mountainSpeed * -1)
            this.mountainGroup.add(mountain);
            if(Phaser.Math.Between(0, 1)){
                mountain.setDepth(1);
            }
            mountain.setFrame(Phaser.Math.Between(0, 3))
            this.addMountains()
        }
    }

    // getting rightmost mountain x position
    getRightmostMountain(){
        let rightmostMountain = -200;
        this.mountainGroup.getChildren().forEach(function(mountain){
            rightmostMountain = Math.max(rightmostMountain, mountain.x);
        })
        return rightmostMountain;
    }

    // the core of the script: platform are added from the pool or created on the fly
    addPlatform(platformWidth, posX, posY){
        this.addedPlatforms ++;
        let platform;
        if(this.platformPool.getLength()){
            platform = this.platformPool.getFirst();
            platform.x = posX;
            platform.y = posY;
            platform.active = true;
            platform.visible = true;
            this.platformPool.remove(platform);
            let newRatio =  platformWidth / platform.displayWidth;
            platform.displayWidth = platformWidth;
            platform.tileScaleX = 1 / platform.scaleX;
        }
        else{
            platform = this.add.tileSprite(posX, posY, platformWidth, 32, "platform");
            this.physics.add.existing(platform);
            platform.body.setImmovable(true);
            platform.body.setVelocityX(Phaser.Math.Between(gameOptions.platformSpeedRange[0], gameOptions.platformSpeedRange[1]) * -1);
            platform.setDepth(2);
            this.platformGroup.add(platform);
        }
        this.nextPlatformDistance = Phaser.Math.Between(gameOptions.spawnRange[0], gameOptions.spawnRange[1]);

        // if this is not the starting platform...
        if(this.addedPlatforms &gt; 1){

            // is there a coin over the platform?
            if(Phaser.Math.Between(1, 100) <= gameOptions.coinPercent){
                if(this.coinPool.getLength()){
                    let coin = this.coinPool.getFirst();
                    coin.x = posX;
                    coin.y = posY - 96;
                    coin.alpha = 1;
                    coin.active = true;
                    coin.visible = true;
                    this.coinPool.remove(coin);
                }
                else{
                    let coin = this.physics.add.sprite(posX, posY - 96, "coin");
                    coin.setImmovable(true);
                    coin.setVelocityX(platform.body.velocity.x);
                    coin.anims.play("rotate");
                    coin.setDepth(2);
                    this.coinGroup.add(coin);
                }
            }

            // is there a fire over the platform?
            if(Phaser.Math.Between(1, 100) <= gameOptions.firePercent){
                if(this.firePool.getLength()){
                    let fire = this.firePool.getFirst();
                    fire.x = posX - platformWidth / 2 + Phaser.Math.Between(1, platformWidth);
                    fire.y = posY - 46;
                    fire.alpha = 1;
                    fire.active = true;
                    fire.visible = true;
                    this.firePool.remove(fire);
                }
                else{
                    let fire = this.physics.add.sprite(posX - platformWidth / 2 + Phaser.Math.Between(1, platformWidth), posY - 46, "fire");
                    fire.setImmovable(true);
                    fire.setVelocityX(platform.body.velocity.x);
                    fire.setSize(8, 2, true)
                    fire.anims.play("burn");
                    fire.setDepth(2);
                    this.fireGroup.add(fire);
                }
            }
        }
    }

    // the player jumps when on the ground, or once in the air as long as there are jumps left and the first jump was on the ground
    // and obviously if the player is not dying
    jump(){
        if((!this.dying) &amp;&amp; (this.player.body.touching.down || (this.playerJumps &gt; 0 &amp;&amp; this.playerJumps < gameOptions.jumps))){
            if(this.player.body.touching.down){
                this.playerJumps = 0;
            }
            this.player.setVelocityY(gameOptions.jumpForce * -1);
            this.playerJumps ++;

            // stops animation
            this.player.anims.stop();
        }
    }

    update(){

        // game over
        if(this.player.y &gt; game.config.height){
            this.scene.start("PlayGame");
        }

        this.player.x = gameOptions.playerStartPosition;

        // recycling platforms
        let minDistance = game.config.width;
        let rightmostPlatformHeight = 0;
        this.platformGroup.getChildren().forEach(function(platform){
            let platformDistance = game.config.width - platform.x - platform.displayWidth / 2;
            if(platformDistance < minDistance){
                minDistance = platformDistance;
                rightmostPlatformHeight = platform.y;
            }
            if(platform.x < - platform.displayWidth / 2){
                this.platformGroup.killAndHide(platform);
                this.platformGroup.remove(platform);
            }
        }, this);

        // recycling coins
        this.coinGroup.getChildren().forEach(function(coin){
            if(coin.x < - coin.displayWidth / 2){
                this.coinGroup.killAndHide(coin);
                this.coinGroup.remove(coin);
            }
        }, this);

        // recycling fire
        this.fireGroup.getChildren().forEach(function(fire){
            if(fire.x < - fire.displayWidth / 2){
                this.fireGroup.killAndHide(fire);
                this.fireGroup.remove(fire);
            }
        }, this);

        // recycling mountains
        this.mountainGroup.getChildren().forEach(function(mountain){
            if(mountain.x < - mountain.displayWidth){
                let rightmostMountain = this.getRightmostMountain();
                mountain.x = rightmostMountain + Phaser.Math.Between(100, 350);
                mountain.y = game.config.height + Phaser.Math.Between(0, 100);
                mountain.setFrame(Phaser.Math.Between(0, 3))
                if(Phaser.Math.Between(0, 1)){
                    mountain.setDepth(1);
                }
            }
        }, this);

        // adding new platforms
        if(minDistance &gt; this.nextPlatformDistance){
            let nextPlatformWidth = Phaser.Math.Between(gameOptions.platformSizeRange[0], gameOptions.platformSizeRange[1]);
            let platformRandomHeight = gameOptions.platformHeighScale * Phaser.Math.Between(gameOptions.platformHeightRange[0], gameOptions.platformHeightRange[1]);
            let nextPlatformGap = rightmostPlatformHeight + platformRandomHeight;
            let minPlatformHeight = game.config.height * gameOptions.platformVerticalLimit[0];
            let maxPlatformHeight = game.config.height * gameOptions.platformVerticalLimit[1];
            let nextPlatformHeight = Phaser.Math.Clamp(nextPlatformGap, minPlatformHeight, maxPlatformHeight);
            this.addPlatform(nextPlatformWidth, game.config.width + nextPlatformWidth / 2, nextPlatformHeight);
        }
    }
};
A comprehensive guide about scale management will be part of the next update of my book about HTML5 game development so grab your copy today and have all future updates for free, meanwhile download the source code of this project.

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214 GAME PROTOTYPES EXPLAINED WITH SOURCE CODE
// 1+2=3
// 100 rounds
// 10000000
// 2 Cars
// 2048
// A Blocky Christmas
// A Jumping Block
// A Life of Logic
// Angry Birds
// Angry Birds Space
// Artillery
// Astro-PANIC!
// Avoider
// Back to Square One
// Ball Game
// Ball vs Ball
// Ball: Revamped
// Balloon Invasion
// BallPusher
// Ballz
// Bar Balance
// Bejeweled
// Biggification
// Block it
// Blockage
// Bloons
// Boids
// Bombuzal
// Boom Dots
// Bouncing Ball
// Bouncing Ball 2
// Bouncy Light
// BoxHead
// Breakout
// Bricks
// Bubble Chaos
// Bubbles 2
// Card Game
// Castle Ramble
// Chronotron
// Circle Chain
// Circle Path
// Circle Race
// Circular endless runner
// Cirplosion
// CLOCKS - The Game
// Color Hit
// Color Jump
// ColorFill
// Columns
// Concentration
// Crossy Road
// Crush the Castle
// Cube Jump
// CubesOut
// Dash N Blast
// Dashy Panda
// Deflection
// Diamond Digger Saga
// Don't touch the spikes
// Dots
// Down The Mountain
// Drag and Match
// Draw Game
// Drop Wizard
// DROP'd
// Dudeski
// Dungeon Raid
// Educational Game
// Elasticity
// Endless Runner
// Erase Box
// Eskiv
// Farm Heroes Saga
// Filler
// Flappy Bird
// Fling
// Flipping Legend
// Floaty Light
// Fuse Ballz
// GearTaker
// Gem Sweeper
// Globe
// Goat Rider
// Gold Miner
// Grindstone
// GuessNext
// Helicopter
// Hero Emblems
// Hero Slide
// Hexagonal Tiles
// HookPod
// Hop Hop Hop Underwater
// Horizontal Endless Runner
// Hundreds
// Hungry Hero
// Hurry it's Christmas
// InkTd
// Iromeku
// Jet Set Willy
// Jigsaw Game
// Knife Hit
// Knightfall
// Legends of Runeterra
// Lep's World
// Line Rider
// Lumines
// Magick
// MagOrMin
// Mass Attack
// Math Game
// Maze
// Meeblings
// Memdot
// Metro Siberia Underground
// Mike Dangers
// Mikey Hooks
// Nano War
// Nodes
// o:anquan
// One Button Game
// One Tap RPG
// Ononmin
// Pacco
// Perfect Square!
// Perfectionism
// Phyballs
// Pixel Purge
// PixelField
// Planet Revenge
// Plants Vs Zombies
// Platform
// Platform game
// Plus+Plus
// Pocket Snap
// Poker
// Pool
// Pop the Lock
// Pop to Save
// Poux
// Pudi
// Pumpkin Story
// Puppet Bird
// Pyramids of Ra
// qomp
// Quick Switch
// Racing
// Radical
// Rebuild Chile
// Renju
// Rise Above
// Risky Road
// Roguelike
// Roly Poly
// Run Around
// Rush Hour
// SameGame
// SamePhysics
// Save the Totem
// Security
// Serious Scramblers
// Shrink it
// Sling
// Slingy
// Snowflakes
// Sokoban
// Space Checkers
// Space is Key
// Spellfall
// Spinny Gun
// Splitter
// Spring Ninja
// Sproing
// Stabilize!
// Stack
// Stick Hero
// String Avoider
// Stringy
// Sudoku
// Super Mario Bros
// Surfingers
// Survival Horror
// Talesworth Adventure
// Tetris
// The Impossible Line
// The Moops - Combos of Joy
// The Next Arrow
// Threes
// Tic Tac Toe
// Timberman
// Tiny Wings
// Tipsy Tower
// Toony
// Totem Destroyer
// Tower Defense
// Trick Shot
// Tunnelball
// Turn
// Turnellio
// TwinSpin
// vvvvvv
// Warp Shift
// Way of an Idea
// Whack a Creep
// Wheel of Fortune
// Where's my Water
// Wish Upon a Star
// Word Game
// Wordle
// Worms
// Yanga
// Yeah Bunny
// Zhed
// zNumbers