Dynamically resize the pixi stage and it's contents on window resize and window load

Question

I'm trying to dynamically resize the pixi stage (canvas and contents) on window resize. And also have it initially load at the size of the browser window without changing ratio.

I'm using the following to set the initial size basically to window.innerWidth & window.innerHeight.

But it's doing something strange, it's loading at a smaller size (but not the size of the canvas specified in the html) then it's expanding to fit the window.

var w;
var h;
    
window.onload = function() {
    var w = window.innerWidth;
    var h = window.innerHeight;

    //this part resizes the canvas but keeps ratio the same
    renderer.view.style.width = w + "px";
    renderer.view.style.height = h + "px"

//  init();
}; 

Here's my onresize function - it's resizing the canvas, but not the content.

I thought being that it's updating the renderer.view, it would resize the content, but it's not doing so.

How do I resize the content of the stage/renderer.view content?

window.onresize = function (event){
    var w = window.innerWidth;
    var h = window.innerHeight;

    //this part resizes the canvas but keeps ratio the same
    renderer.view.style.width = w + "px";
    renderer.view.style.height = h + "px";

    //this part adjusts the ratio:
    renderer.resize(w,h);
}

    // create an new instance of a pixi stage
    var stage = new PIXI.Stage(0xff00ff);
    var renderer = PIXI.autoDetectRenderer(window.innerWidth, window.innerHeight);

    // add the renderer view element to the DOM
   var mypixiStage = document.body.appendChild(renderer.view);

Answer 1

You will want to setup a size and ratio for the resize event function to reference. Then, you'll need a resize function that checks the window size in order to keep the ratio when resized. I'm also running the resize function manually to start for initial page load.

Also, note that I'm not running renderer.resize. I'm just resizing the drawing area.

Here's a fiddle for you to look at: http://jsfiddle.net/2wjw043f/

Here's the fiddle code:

var size = [1920, 1080];
var ratio = size[0] / size[1];
var stage = new PIXI.Stage(0x333333, true);
var renderer = PIXI.autoDetectRenderer(size[0], size[1], null);
document.body.appendChild(renderer.view);
var texture = new PIXI.RenderTexture();
r1 = new PIXI.Graphics();
r1.beginFill(0x00ffff);
r1.drawRect(0, 0, 100, 100);
r1.endFill();
texture.render(r1);
var block = new PIXI.Sprite(texture);
block.position.x = 100;
block.position.y = 100;
block.anchor.x = .5;
block.anchor.y = .5;
stage.addChild(block);
requestAnimFrame(animate);
resize();
function animate() {
    requestAnimFrame(animate);
    block.rotation += .01;
    renderer.render(stage);
}
function resize() {
    if (window.innerWidth / window.innerHeight >= ratio) {
        var w = window.innerHeight * ratio;
        var h = window.innerHeight;
    } else {
        var w = window.innerWidth;
        var h = window.innerWidth / ratio;
    }
    renderer.view.style.width = w + 'px';
    renderer.view.style.height = h + 'px';
}
window.onresize = resize;

Answer 2

Starting from PixiJS 5.0 you can simply use the resizeTo property of your Application:

let app = new PIXI.Application({ resizeTo: window });

Documentation: http://pixijs.download/release/docs/PIXI.Application.html#Application

Answer 3

I been using Pixi.js for a few weeks and worked on the same problem of resizing the canvas. This class creates a sprite that has a method "applyResize" that does most of the work. The size of the canvas background will equal the same as the parent "domElement" in the constructor. You have to add 'resize' event listener to the sprite after initializing it. Or you can do something else to improve it.

class PixiBackground {

    constructor(type = 'cover', domElement, imgUrl) {
        this.domElement = domElement;
        this.imgUrl = imgUrl;
        this.parent = new PIXI.Container();
        this.sprite = new PIXI.Sprite.fromImage(this.imgUrl);
        this.parent.addChild(this.sprite);
        this.type = type;
    }

    addTo(container) {
        container.addChild(this.parent);
        this.applyResize();
    }

    applyResize() {
        const domSize = {
            x: this.domElement.clientWidth,
            y: this.domElement.clientHeight
        };
        const imageSize = {
            x: this.sprite.texture.width,
            y: this.sprite.texture.height
        };
        const domElementRatio = domSize.x / domSize.y;
        const imageRatio = imageSize.x / imageSize.y;
        var scale = 1;
        var position = new PIXI.Point(0, 0);

        if (this.type == 'cover' ? domElementRatio > imageRatio : domElementRatio < imageRatio) {
            //photo is taller than background
            scale = domSize.x / imageSize.x;
            position.y = -(imageSize.y * scale - domSize.y) / 2;
            position.x = 0;
        } else {
            //photo is wider than background
            scale = domSize.y / imageSize.y;
            position.x = -(imageSize.x * scale - domSize.x) / 2;
            position.y = 0;
        }
        this.sprite.scale = new PIXI.Point(scale, scale);
        this.sprite.position = position;
        return this;
    }
}

const imgUrl = 'https://images.unsplash.com/photo-1528723624453-3e53a413b392?ixlib=rb-0.3.5&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjE0NTg5fQ&s=b44ae61a30e1a05f5defbf48cb5956eb';
const canvasParentElement = document.getElementById('canvasParentElement');
const renderer = PIXI.autoDetectRenderer({
    width: canvasParentElement.clientWidth,
    height: canvasParentElement.clientHeight
});
canvasParentElement.appendChild(renderer.view);

const stage = new PIXI.Container();
const pixiTestObject = new PixiBackground('cover', canvasParentElement, imgUrl);

PIXI.loader.add(imgUrl).load(function() {
    pixiTestObject.addTo(stage)
    requestAnimationFrame(animate);

    function animate() {
        requestAnimationFrame(animate);
        renderer.render(stage);
    }
});

window.addEventListener('resize', debounce(() => onResizeWindow(), 250));
window.addEventListener('resize', debounce(() => pixiTestObject.applyResize(), 250));

// From underscrore.js
function debounce(func, wait, immediate) {
    let timeout;
    return function() {
        let args = arguments;
        let later = () => {
            timeout = null;
            if (!immediate) func.apply(this, args);
        };
        let callNow = immediate && !timeout;
        clearTimeout(timeout);
        timeout = setTimeout(later, wait);
        if (callNow) func.apply(this, args);
    }
}

function onResizeWindow() {
    const canvas = renderer.view;
    const w = canvasParentElement.clientWidth;
    const h = canvasParentElement.clientHeight;
    canvas.style.width = w + 'px';
    canvas.style.height = h + 'px';
    canvas.width = w;
    canvas.height = h;
    renderer.resize(w, h);
}

  #canvasParentElement {
    background: black;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
  }

<script src="https://cdnjs.cloudflare.com/ajax/libs/pixi.js/4.8.1/pixi.min.js"></script>
<div id="canvasParentElement"></div>

Answer 4

app.renderer.resize(window.innerWidth, window.innerHeight);
window.onresize = function()
{
    app.renderer.resize(window.innerWidth, window.innerHeight);
}

Answer 5

For my use case, I only need to scale a sprite based on its width. I do this using the scale function and clamping it to a max value of 1:

sprite.scale.set(Math.min(app.screen.width / sprite.texture.width, 1))

Starting with PixiJS 5.3.0 there's an resize event emitted on the renderer. This is thanks to issue #6081 opened by Fabian von Ellerts that he mentioned in his comment.

app.renderer.on('resize', (width, height) => {
  sprite.scale.set(Math.min(width / sprite.texture.width, 1))
})

?? This will only set the dimensions of the sprite. You'll still need to position it on the canvas in a similar manner, i.e also scale its position.

Answer 6

adaptive-scale is very useful for resizing and scaling things