Canvas rendering animation slow on safari - javascript

Recently I am working on a animation draw on canvas. The animation is to create a radical gradient circle and move the outside circle from one side to the opposite. So it looks like the search light effect.
The Html code is
<canvas id="intro-canvas"></canvas>
The javascript part is:
var canvas = document.getElementById("intro-canvas");
var ctx = canvas.getContext("2d");
canvas.width = $window_w;
canvas.height = $window_h;
var $start = 0;
var $frames = 120;
function intro() {
(function animloop() {
$start++;
if ($start <= $frames) {
$canvas_timer = requestAnimFrame(animloop);
render_canvas();
}
})();
}
var $xmin = (window.innerWidth - 635) / 2;
var $xmax = $xmin + 635;
var $ymin = (window.innerHeight - 300) / 2;
var $ymax = $ymin + 300;
var centerx = randomIntFromInterval($xmin, $xmax);
var centery = randomIntFromInterval($ymin, $ymax);
var center_disx = randomIntFromInterval(450, 500);
var center_disy = randomIntFromInterval(450, 500);
var xstep = (center_disx + center_disx - 280) / 120;
var ystep = (center_disy + center_disy - 280) / 120;
if (centerx > window.innerWidth / 2) {
var centerx2 = centerx + center_disx;
} else {
var centerx2 = centerx - center_disx;
}
if (centery > window.innerHeight / 2) {
var centery2 = centery + center_disy;
} else {
var centery2 = centery - center_disy;
}
var $r1 = randomIntFromInterval(150, 200);
var $r2 = $r1 + randomIntFromInterval(700, 750);
function render_canvas() {
ctx.clearRect(0, 0, $window_w, $window_h);
var grd = ctx.createRadialGradient(centerx, centery, $r1, centerx2, centery2, $r2);
$r2 -= 2;
if (centerx > window.innerWidth / 2) {
centerx2 -= (xstep);
} else {
centerx2 += (xstep);
}
if (centery > window.innerHeight / 2) {
centery2 -= (ystep);
} else {
centery2 += (ystep);
}
grd.addColorStop(0, "#531f69");
grd.addColorStop(0.5, "#8e217d");
grd.addColorStop(1, "#ffffff");
ctx.fillStyle = grd;
ctx.fillRect(0, 0, $window_w, $window_h);
}
function render_last_canvas() {
$('#intro > img').animate({
opacity : 1
}, 2000);
}
function randomIntFromInterval(min, max) {
return Math.floor(Math.random() * (max - min + 1) + min);
}
Now the code is working good in chrome but when it comes to safari, the animation becomes very slow. Does anyone have any idea of the performance of canvas radical gradient animation on safari?
Interesting thing is in jsfiddle: http://jsfiddle.net/lhray/qVLps/, it works fine.
Thanks for any ideas.
BTW, my safari is 7.0.4 and OS is OS X 10.9.3

I think this issue is inherent to the Apple WebKit browser engine. Somehow chrome browser engine is able to use WebGL more efficient than Safari.
That's the only thing that explains why the fiddle works fine in safari, but when it comes to safari itself, the rendering process becomes slow.
This article compares Safari canvas performance.
Here's a related question as well:
Canvas drawing takes a lot of time on Safari but not on Chrome or FF

Related

Pure Javascript particle repeller from base64 encoded png

I have some js code that i copied from a youtube tutorial and adapted for my own project to fill the header, the code works as intended and it works when the viewport is smaller than around 1200px, however when i put firefox into full screen the animation does not play & the image is being stretched, not retaining its aspect ratio. I do have a 10/15 year old gpu so i'm guessing thats half my issue. The script uses a png image file of 100x100 pixels, which it then converts into particle color values. Can this be optimized or made to run better. it seems that the wider the viewport the longer the animation takes to kick in, until it finally stops & doesn't work. full screen= [2550x1440]...
The original tutorial is here: Pure Javascript Particle Animations & to convert an image to base64 encoding is here: Image to base64.
HTML:
<html>
<body>
<canvas id="CanV"></canvas>
</body>
</html>
CSS:
#Canv{
position:absolute;
top:-1px;left:-2px;
z-index:67;
width:100vw !important;
max-height: 264px !important;
min-height: 245px !important;
filter:blur(2.27px);
}
Javascript:
window.addEventListener("DOMContentLoaded",(e)=>{
const canv = document.getElementById('Canv');
const ctx = canv.getContext('2d');
canv.width = window.innerWidth;
canv.height = window.innerHeight/ 3.85;
let particleArray = [];
let mouse = {
x: null,
y: null,
radius: 74
}
window.addEventListener('mousemove',(e)=>{
mouse.x = event.x + canv.clientLeft/2;
mouse.y = event.y + canv.clientTop/1.2;
});
function drawImage(){
let imageWidth = png.width; //These to values crop if / sum no.
let imageHeight = png.height;
const data = ctx.getImageData(0, 0, imageWidth, imageHeight); //Gets img data for particles
ctx.clearRect(0,0, canv.width, canv.height); // Clears the original img as its now being stored in the variable data.
class Particle {
constructor(x, y, color, size){
this.x = x + canv.width/2 - png.width * 174, //Chngd Ok:74
this.y = y + canv.height/2 - png.height * 32, //Ch<2 Ok:16
this.color = color,
this.size = 2.28, // Particle Size > Changed this value. from 2 i think!.
this.baseX = x + canv.width/1.8 - png.width * 3.1, //Chngd ok:5.1
this.baseY = y + canv.height/1.2 - png.height * 2.8,
this.density = (Math.random() * 14) + 2;
}
draw() {
ctx.beginPath(); // this creates the sort of force field around the mouse pointer.
ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);
ctx.closePath();
ctx.fill();
}
update() {
ctx.fillStyle = this.color;
// Collision detection
let dx = mouse.x - this.x;
let dy = mouse.y - this.y;
let distance = Math.sqrt(dx * dx + dy * dy);
let forceDirectionX = dx / distance;
let forceDirectionY = dy / distance;
// Max distance, past that the force will be 0
const maxDistance = 144;
let force = (maxDistance - distance) / maxDistance;
if (force < 0) force = 0;
let directionX = (forceDirectionX * force * this.density * 0.6);
let directionY = (forceDirectionY * force * this.density * 8.7); //Ch.this
if (distance < mouse.radius + this.size) {
this.x -= directionX;
this.y -= directionY;
} else {
if (this.x !== this.baseX){
let dx = this.x - this.baseX;
this.x -= dx/54; // Speed Particles return to ori
} if (this.y !== this.baseY){
let dy = this.y - this.baseY;
this.y -= dy/17; // Speed Particles return to ori
}
}
this.draw();
}
}
function init(){
particleArray = [];
for(let y = 0, y2 = data.height; y<y2; y++){
for(let x =0, x2 = data.width; x<x2; x++){
if(data.data[(y * 4 * data.width) + (x*4) + 3] > 128){
let positionX = x + 25;
let positionY = y + 45; // Co-ords on Canv
let color = "rgb(" + data.data[(y * 4 * data.width) + (x * 4)] + "," +
data.data[(y * 4 * data.width) + (x * 4) + 1] + "," +
data.data[(y * 4 * data.width) + (x * 4) + 2] + ")";
particleArray.push(new Particle(positionX * 2, positionY * 2, color));
} /* These number effect png size but its to high */
}
}
}
function animate(){
requestAnimationFrame(animate);
ctx.fillStyle = 'rgba(0,0,0,.07)';
ctx.fillRect(0,0, innerWidth, innerHeight);
for(let i =0; i < particleArray.length; i++){
particleArray[i].update();
}
}
init();
animate();
}
const png = new Image();
png.src = "RemovedBase64StringToBig";
window.addEventListener('load',(e)=>{
console.log('page has loaded');
ctx.drawImage(png, 0, 0);
drawImage();
})
});
have managed to shorten it by about 100 characters by shortening all the variable names > PartArr, ImgWidth, DirX, DirY etc, but apart from minifying it is there any other ways to optimize this? and fix the full screen issue?
I tried to add it to a JSfiddle, So I could link to it here, but I don't think this is allowing the base64 string, its not loading anything anyway. The canvas loads, with the bg just no image or animation.
I've found out what part of the problem is with full screen, the cursor position is actually about 300px to the right of where the actual cursor is, but I still have no idea how to fix this or fix the major lagging performance issues. Guessing its alot to compute even just with 100x100.
One option I can think of to make this perform better would be to move it & its calculations, into its own dedicated web worker & convert the image to Webp but i'm still not very clued up about web workers or how to implement them properly.. Will play around & see what I can put together using All the suggestions in the comments & answers.
I'm adding these links only for future reference, when I come back to this later on:
MDN Canvas Optimizations
Html5Rocks Canvas Performance
Stack Question. Canv ~ Opti
Creating A blob From A Base 64 String in Js
Secondary bonus Question,
is there a maximum file size or max px dimensions,
that can be base64 encoded? only asking this as someone on facebook has recently sent me a question regarding another project with multiple base64 encoded images and I was unsure of the answer..
Shortening your code doesn't help much with performance. I'm using Firefox. To check what's taking your time up the most during browser runs in Firefox, you can read Performance from MDN.
The problem with your solution is your fps is dropping hard. This happens because you are painting each Particle every frame. Imagine how laggy it will be when there are thousands of Particles that you need to paint every frame. This paint call is called from your function Particle.draw (which calls the following: ctx.beginPath, ctx.arc, and ctx.closePath). This function, as said, will be called because of Particle.update for each frame. This is an extremely expensive operation. To improve your fps drastically, you can try to not draw each Particle individually, but rather gather all the Particles' ImageData wholly then placing it in the canvas only once in rAQ (thus only one paint happens). This ImageData is an object that contains the rgba for each pixel on canvas.
In my solution below, I did the following:
For each Particle that is dirty (has been updated), modify the ImageData that is to be put in the canvas
Then, after the whole ImageData has been constructed for one frame, only draw once to the canvas using putImageData. This saves a lot of the time needed to call your function Particle.update to draw each Particle individually.
One other obvious solution is to increase the size of Particles so that there are fewer Particles' pixels that are needed to be processed (to alter ImageData). I've also tweaked the code a little so that the image will always be at least 100px high; you can tweak the maths so that the image will always maintain your aspect ratio and respond to window size.
Here's a working example:
const canvas = document.querySelector('#canvas1')
const ctx = canvas.getContext('2d')
canvas.width = window.innerWidth
canvas.height = window.innerHeight
let canvasWidth = canvas.width
let canvasHeight = canvas.height
let particleArray = []
let imageData = []
// mouse
let mouse = {
x: null,
y: null,
radius: 40
}
window.addEventListener('mousemove', e => {
mouse.x = event.x
mouse.y = event.y
})
function drawImage(width, height) {
let imageWidth = width
let imageHeight = height
const data = ctx.getImageData(0, 0, imageWidth, imageHeight)
class Particle {
constructor(x, y, color, size = 2) {
this.x = Math.round(x + canvas.width / 2 - imageWidth * 2)
this.y = Math.round(y + canvas.height / 2 - imageHeight * 2)
this.color = color
this.size = size
// Records base and previous positions to repaint the canvas to its original background color
this.baseX = Math.round(x + canvas.width / 2 - imageWidth * 2)
this.baseY = Math.round(y + canvas.height / 2 - imageHeight * 2)
this.previousX = null
this.previousY = null
this.density = (Math.random() * 100) + 2
}
stringifyColor() {
return `rgba(${this.color.r}, ${this.color.g}, ${this.color.b}, ${this.color.a}`
}
update() {
ctx.fillStyle = this.stringifyColor()
// collision detection
let dx = mouse.x - this.x
let dy = mouse.y - this.y
let distance = Math.sqrt(dx * dx + dy * dy)
let forceDirectionX = dx / distance
let forceDirectionY = dy / distance
// max distance, past that the force will be 0
const maxDistance = 100
let force = (maxDistance - distance) / maxDistance
if (force < 0) force = 0
let directionX = (forceDirectionX * force * this.density)
let directionY = (forceDirectionY * force * this.density)
this.previousX = this.x
this.previousY = this.y
if (distance < mouse.radius + this.size) {
this.x -= directionX
this.y -= directionY
} else {
// Rounded to one decimal number to as x and y cannot be the same (whole decimal-less integer)
// as baseX and baseY by decreasing using a random number / 20
if (Math.round(this.x) !== this.baseX) {
let dx = this.x - this.baseX
this.x -= dx / 20
}
if (Math.round(this.y) !== this.baseY) {
let dy = this.y - this.baseY
this.y -= dy / 20
}
}
}
}
function createParticle(x, y, size) {
if (data.data[(y * 4 * data.width) + (x * 4) + 3] > 128) {
let positionX = x
let positionY = y
let offset = (y * 4 * data.width) + (x * 4)
let color = {
r: data.data[offset],
g: data.data[offset + 1],
b: data.data[offset + 2],
a: data.data[offset + 3]
}
return new Particle(positionX * 4, positionY * 4, color, size)
}
}
// Instead of drawing each Particle one by one, construct an ImageData that can be
// painted into the canvas at once using putImageData()
function updateImageDataWith(particle) {
let x = particle.x
let y = particle.y
let prevX = particle.previousX
let prevY = particle.previousY
let size = particle.size
if (prevX || prevY) {
let prevMinY = Math.round(prevY - size)
let prevMaxY = Math.round(prevY + size)
let prevMinX = Math.round(prevX - size)
let prevMaxX = Math.round(prevX + size)
for (let y = prevMinY; y < prevMaxY; y++){
for (let x = prevMinX; x < prevMaxX; x++) {
if (y < 0 || y > canvasHeight) continue
else if (x < 0 || x > canvasWidth) continue
else {
let offset = y * 4 * canvasWidth + x * 4
imageData.data[offset] = 255
imageData.data[offset + 1] = 255
imageData.data[offset + 2] = 255
imageData.data[offset + 3] = 255
}
}
}
}
let minY = Math.round(y - size)
let maxY = Math.round(y + size)
let minX = Math.round(x - size)
let maxX = Math.round(x + size)
for (let y = minY; y < maxY; y++){
for (let x = minX; x < maxX; x++) {
if (y < 0 || y > canvasHeight) continue
else if (x < 0 || x > canvasWidth) continue
else {
let offset = y * 4 * canvasWidth + x * 4
imageData.data[offset] = particle.color.r
imageData.data[offset + 1] = particle.color.g
imageData.data[offset + 2] = particle.color.b
imageData.data[offset + 3] = particle.color.a
}
}
}
}
function init() {
particleArray = []
imageData = ctx.createImageData(canvasWidth, canvasHeight)
// Initializing imageData to a blank white "page"
for (let data = 1; data <= canvasWidth * canvasHeight * 4; data++) {
imageData.data[data - 1] = data % 4 === 0 ? 255 : 255
}
const size = 2 // Min size is 2
const step = Math.floor(size / 2)
for (let y = 0, y2 = data.height; y < y2; y += step) {
for (let x = 0, x2 = data.width; x < x2; x += step) {
// If particle's alpha value is too low, don't record it
if (data.data[(y * 4 * data.width) + (x * 4) + 3] > 128) {
let newParticle = createParticle(x, y, size)
particleArray.push(newParticle)
updateImageDataWith(newParticle)
}
}
}
}
function animate() {
requestAnimationFrame(animate)
for (let i = 0; i < particleArray.length; i++) {
let imageDataCanUpdateKey = `${Math.round(particleArray[i].x)}${Math.round(particleArray[i].y)}`
particleArray[i].update()
updateImageDataWith(particleArray[i])
}
ctx.putImageData(imageData, 0, 0)
}
init()
animate()
window.addEventListener('resize', e => {
canvas.width = innerWidth
canvas.height = innerHeight
canvasWidth = canvas.width
canvasHeight = canvas.height
init()
})
}
const png = new Image()
png.src = " 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jLZBYxKBFJDP/sjU2xrJtKvfaaAx+rtGPDuE8/ayI0woxXY5zAGPeJCd+YGQ7DLPi5dovF5+bYSvKcfuZEaIQZw5fV1Yd2LlfaTiTe8qrLYX4dVquACRezoD19Hwzu9VR1YyebrdDPnwiNMCPAqR8K/LiG1A0EgGUygGtKe+Xys1nLE9uv13VTUdhBo/GECI1eDAQPV2M9XV+yFIV1g8GWFJYoNDJTUZgViy3fpm/sJtDRtPc9XV8iQqMXBsFjLdZeufyMFQov3Omvdj4P3WAQthOJt3Y6/Wq3WHx+V8Ry3DOddeImQiPMzCpSN5V6bU7I4Rdx1oGAMSva2M8MB7qBwJ3fHKAXC2HqqzH5oEg3GBTtpLwczgqFF3fZusBb7zsfK0QvHMLU4bDZfDxIJt/I5lcpvhqsWAx4HPXatAvhX1ZXH97EAjkrFF70VBX2S6Vf9ut1nQiNQLjlxfDdYvH5TjZbkS6Gi7aym0qB6ZFqDAMgDUVhLUVhHU17fxPfk6fjwk18PyI0AuGMamyvXH5mp9OvrFgMRrUa9KNR2IpEZP8Y6+n60rTuVMqkYudypdZ4aRzsdBoMRYGWorCbEOu3E4m3PVUF8w5vDtCLinDjL/pjw7jPM70Yml+H1SoMKxUwFQX60ahw8dv5/Mtpn9wNq9UFw++3uqnU651sFgxFAcPvh7aqgsGrSzuff3kTk07UGu/qcIBeZIQbqcLsXK6EAv63zU0weUtp53Jw2GwKIjP5wd1p18ZwP9Tw+y2DV2QtRYH9eh0MRYF2KASGzwftUAi2IhG4qZgfycrCiNAIhCvSw0a12vxWJLKGNyhlYf/7YACDZBJ2slmwFAVYJrNocBf/tFdjo1pt3vD5+thWGuNqCPC/h9UqGPzyE/5dR9PAuKGd0d1i8TkearmL9hV6ARKurGJBiwWK+j1dF+tHvI0ELlpDT9fFpNILU7lvm5sqJzHW0bRxBcYJqx0KgRWPA+pm3VQK2qoKO9ksoKY2qtXmb2LaeWwY983xbVCwYrFlIjQC4RIvcjuff2nMzQ2wCutHo4K8ZHSDQehoGuDeISsUXnjN1d4OhT4ZigI72SyY4fCY0ObmwPD5xpoZJzk7nwfD5+u3Q6FPt5HkId0IvXPDAXphEi5NYqxQeGGGwx8crv1AADqaNrZapFLi7/D/NxWF7RaLz728QI1WDFGh+XyiQutoGraWsJPNwm0eLzlaWXmEbzC3ccSFCI0w9dgrl591AwFDJrHtREK0lRZ/IfPARLRcCN/YrFwnMiTtTG47kcwMRYFRrQa3XRnd1eEAvVgJ57rc7VyutFcuPzN5LI9cdaFOhsGJZjgM/WgU7HT61XYi8Xbaq7Fjw7g/rFSeXqYt3MlmK9yGAR1NA7Rp2Pm8ILTdYhFuWxfkU2W4azcH6IVLOEViPV1fwvywYbUKB40Gto1gzM0JMmtP2KkcVqsL066NHTabjzua9h6rrcvE7nzb3FTx8wbJpCAxw+8f62l+/7jljsff3bY0gMOB7UTiLREa4c6lNchL4KiB2fk8prw6lsL70SiY4TCYisL60ejytMdYHxvGfVYovDAUhRk+X9+Kx6GbSglLxWVI2AyHPxhju4nQ0WSrRjcYBOOMymhUq83f1MYDt8yAqShs1kItidAIEysVlsksyl6xQTIJPV0fH9blrdRuseieWjJMf532oyJf19cfWPH4O0NRmBWPgzE3J0R82T9m53Klyzxv7VDokxkOjyszfqOgp+vACgUkNJHz/21zUx1Wqwsm3+28qUPF0k0F2CuXnxGhEWYSo1pt3lGNxWLACgVht9gtFsHkFch+qQR2LjfWyPjneGlydmwY99EEi8J9PxqFtqqCTEiXdfLj10T7Bu5tdjQNthMJ/O/3Zjj8AT92r1wGyYx7I6tJViy2zHVPRoRGmCltDHUxua00JcsFtpX79Tp0UykwFAUOGo0n24nE256uL3ntxBuip+tLbVUda15zc6KiQvsFn1Zeyslv53Il3NM0xtfVxUK9ncuNtyCwBeUfY4bDonpr3RDB4OaApShs2pf7idAIP1yNma71o1PG10AAthMJsGIxwOXmUa02PwvGzMNm83FrfOnpRMTnRNNWVVGlsUxm8Sc2B8AMh6EdCkFP12E7kRBkiV8Xl9QFxqTKbmIS+nV9/YF1srmxRIRG8OQupZ3Pv5TbSjudBiseP0Vk/WjUYcXYikTW9srlZ154N/+2ual+WV19+GV19eFFxGsoCmuHQrBbLJ60fZkMdDRt3Db6fJeumkxusjX8fjD8fmCZjCCv7URCfC8kONmrZnAt7Saep24w2GrzWKFZHw4QAczYPqWdTr86qxpDjayn67AViUA3lUIT7BpqY9P+Cz+q1ebtdPqVoSisraobSBBmOPzBDIc/nCW275XLz9DF3w6FoB+NCs8Yks1eufzsMgd79+t13U6nX8lbA7KuhvudkgGXGYrC7FyudJPWFkkznfnNASKCGWkrB8nkG7c2hq1kW1UdB0UwpqcfjS6zTGZx2qsxPJCCy+GSNcJBJOeFKX4fDO61FIUZfj/sFotCxLdzOdF6tkOhS1dprfEJPUFiPV0fTzszGdjJZmEnm8XBSuk2zbbmyU2GFhEaYSrbyt1i8XlP15dYofACbRY72SwMq1Xo6ToMKxXHTuVeuQzDSuVpW1U39kulX6b934cvRCSxdigEcoCimFDigjgX/M+aWI5qtXnRIs7NiY+302lRsRmKwi4z/LBzuZLY7fT7x8OVWAz2SyWZZOG2fXo8UBOsS/77iNAIN4JhpfK0H43Cb6OR40p4T9dhkEw6xH40Vw6r1QUvVGODZPJNi+s98u5kiwv53VRKWCMcQvsJSU0U3HE4wDIZ0QZ2g0Eh6OPXuoyzHjcHsEJDYnQPIIxbtk3gcIBflX9FhEa4dQF8VKvND6vVhX40uoy7eriWJG5TBoPQ5svhaNHYK5efTbM2hufqDL/fkoMTf/v8GVq8grJzOdiv12E7kYBhtQqDZHK8qYBeMrlaO4dAWmPtzfGx7VBobLHgX6OlKOwyy/SDZPLNqFYDO58XROmoJvnjue2dyruwsE5k4QEi+7q+/mA7kXgrH9c1+QseU19dC+NLo1pt3itLyXIVxjPTxhWY3y+8XG1VRT/Xx5aifDQU5aMxNwdy2CK2fUggk6rR3WLxeUfTHNqbnU47883GFVblMhrmdiLxVkwxkVT9/hOt75K2kGup6qvVBZx8T/uqGhHajIJlMosTJpbilJt5smPJTEVh+6XSL17zjh00Gk+2IpE1jLNGYmCZjKNta6sqfNvcnJOI8KOYIKKO5vMJEplESt8Hg3vtUOhTN5USRMgKBbBzOQcZdVOp15cdDrgfrxkOi+EDf/wbkyplDMq8icnnrFdpRBpT1nrJzn58N8XYavmkm8goCwZbg2TyzbRXY19WVx+eZ4nAhW8BWeQ/aSPh2DD+SdLb/mtH0/63wy7h8+FREjD8fmsSgQySyTdmOCxIrKNp431VXg2a4TC0FIVdJv7Izudf2rkcGH7/yffnX1s22crPwX69rqOVY1SrwU42W7nuNyMcDnh584MIzQP+sW4q9ZqTFy6KMxFlzQ2x24kEDJLJN+5J4FQPL6rVBUy3PU8Yt/P5l7J3yyXyC8MqKxT+1dWufpQnjAa/W4DpF8NK5emkwUNbVTdwOR0JBz8PY4Euk8mPmwOi8uOR3FYs5h5gMJH6gcZcroW6Ce+63li4ZQdm0WRLhHLLEz0rFlu2zjDCynqZxRMhvODgxxNv6BtDj9d5+5LyKpGDzCThngv2Hx0teaHwr+71IlxFMvx+MMPhD2fpdhhOaafTskYnf79LOeuxlZV0vHFmHJL0hHRb+VLUdiJxI/c7Lb4GNos6GhHLLWC/Xtf70aggsq1IZGy5UFUYVirjnUpXVA8rFF54wcUvBydO2F88k2AAxsc9JhKa1HIaivLxsNkMSFXqPxmK8tEt6mP11TrjUAhuDrBMRhCOGQ47zs9dtmI6aDSeyP922Wwrk5hsG9mv1+Hr+roYTtj5/MvrbgXl61yzRmpEMLcY29MNBoVPbDuREJeReHwP60ejy145uIvVWD8aPXU13FH1+P3WWS9YQQiTCE0itp6u/0+XC/7jpDYVMUlfxM0BKx4XxOP+82dSMRxkLlVqwsIxNwct3g4fNBqwWyxCi5MetqQ3sURunryZrhGhES4l9Nv5/EuT7/C528pBMvkGI6/tXK5k53Klg0bjiVcmlXjabWKqhKSJ7WSzomo6z75wZtspaWktRfkoDwfaqvrvjs9xDRLOelPo6fqS+ygw/m95//IyVcywUnkqNDNM2wiFxEV1rB6/rK46yJ6ngVRuarjDNVswL+m5I0K7w/6xbir1Gs2tPVXdsNPpV3YuV8IrSF/X1x94SZid9FiHlcpTfPE6DvByQmkpCnxdX4fDZtNBEhfljJ1XoZnScGBYqfxLi3vSHHobt3GcZ5I9Wll55IgV4t607UTCTc7sMj/3Fk/2kKedmJY7rFTgt8+foZtKATf5buwWi89v+vdgVk/dEflcA5EdNBpPMDt+FvLE9ut1ndsqTulRX9fXHxhyVSX92dE0+D4YwNHKitOfdU7qrUiYnURm0jFfw+//f4aifLTz+f8xqtUmaXVgKAqTp8LntYiiqvL5xlNOqV10L7x/HwzuoeViUvIsj/w+VSnulcvw2+fPYPh8/Y6mvb/tAY8ULfWKCI0w+5lq42qJ9aPRZWlC9/7MNtHVvu3X63DQaECLE4ysTZ1X9fDBwmk9TNLm5GnhsFIBB6nx4cOPVFZ75fKzlmTixQmprHnhcADjmVrOoQeb9AYgtEBenWHGHBqip+FnfNhsPsbhABEaYWYnsKbskZItCDxex734bedyJayckAg6mibITCaldiiEOtiZraBjOIDJsliZoeHWVQ12UykRqNjieuWPttGtCVNZcaLO9diRtLuplKgCJ1VaWPm1uMg/rcOd3WLxOSsUXsyKyZZexITx6g2vxs60XJxMGE9VJTySyLEf+XV9/URDkklIWiQ/bzjgvlB+al/T53OI7iYnj1GtNn/ZFaJBMvnGkCeNrimpnEDbVtWxtywWE5sGk25wskLhhZ3Pv5x2yWE7kXi7Wyw+nwVphAiNoLBC4cWptSPci3SmraJRFQxXBfRldfWho8WSp4ZuK4X03+dZIrib3kkuWI0Fgw5C6waDrT/TyuHjl6eO8jV0bGdZJgMsk5Gz0871unlBVuC7wtRyEn5sCugFV79svUCdS0wKJ1Qs24nEKaFcarFO6VlykKKL1C4/HDgdE3QlKzz4+GVXPysU4K+//irsJlgpurXA1g0dPLnKMIB+NLqME3ivpLIQoV3DO9rX9fUHB43Gk2Gl8nS3WHy+FYmseX3R1+DR1LIG5rZfyC0lLsvLrn8U8neLRXF/Uj7b1g6FHMkTksXi05lTuFhs2UGAPt+px8Xb2z/to+L2E4bL5KxQgH8AiLUkN+Fje+4VIsPL8ZbzjCG7TEwSEZpHMaxWF3ay2YqdTr/qqeqG9EvATG47MD1wcPdH26BRrTYvZ/WLSaKkUYnqBSsk7vHCF/Rhs/mYt27ixd+PRk9ieSQ/FrZy3DXPLrU5MGlx/RxSvGwEEA4EWq5jJ3Y+Dy28fJ7LlbxiRj1oNJ6wQuGF63AO24pE1mbxYAoRmCSM93R9qaeqG91gsLUViTgirJHQWCazOO2/zIfN5mPcqfzRx9qSNDB5abodCkFH04SrHU2nUrLFmosYHZWMu8KRP1dqRV9duDkgDxZcj3Mnm61cRZYYvyYFbVUdH5Lh/wYkMa9UY98Hg3v7pdIv+Dsr/w5vRSJrXmqPidB+4sW/k81WTKy+wmH3/UrWDQSMaV/ixVuc7kllPxr9oQgclsksCpKR20/+3x1NE/n7so1C1tLkeGsUzvfrdbDicWGDwAmhO9XiwuGA67CJ7GsbJJNXklJxtLLyyPD5+vzfwPB2pleqsaOVlUdWPP6um0q93opE8Gwh24pE1qbByEuEds2JA91U6nVP15c6mgZYkcnpr3Y6/WratbGDRuOJFY+/c3ipXAdDfqS1EI5/uQJyCfByrpedTsN+vQ6sUICeri99XV9/YIbDH1A/QxLbK5fhsNkEjNWRL5VL5tiLhwPuf5e8NXCFR0i6qdRrw0MpFHj9C994Mb0F9zRnTSMjQpvgt+I/eGbFYkhg46MbHslbx19iPp1kSD6i8jnto/qhXC9HfI/L/yVraXY+D8NKBVihIMyz24kE2LkcsELBMQVsqyr89ddfxwZb6e8cutxlNwdk0j2xb7CrMK96yX4xrFYXrHj8XU/Xl7rBYGs7kXiLQaFeiJsiQvsT7ndrfBC2ZYbDp/L5MW9s2qsxPLhrxWLLjuqJw+0ZwwPD3DR6YSSNGA641o1k4rDzefjt82cYViqnzKdmOAxtVT0hNP65v33+LKwPcku7Vy7Lq0zsrJboaGXlkaEoDG8GnLW0fpmE2Vm1Dc1ScgYRmuuHi2Pqjqa9d5DYWCPz3KQHD4nIFY7Qllzk0g6FhG7FMhlo/aDfSPixsNpDEpFazWPDEBVXT9fFx7qNqR1Ng9ZYR9PdNzaFFUTaHDhvOIBeuYlVKCe1s66mE4jQPC3y85NvTGhisZijIhskk2+86BsTAjnm5uMKECcwYbmQ71Ticd5xpXahzrSTzVYcF5ekigr/7mhlxbEkjn/f03XHwV4rFkPLw0sAUMSSO/96WMnh4z5vcwATZt1pHmK9CiemNxBhTSBCu7HkVOG34SRmzM0Jy8WwWl3wsq7wZXX1oezqnxRKiGkRwvGP1dyY+CbG3UzK88K7mEgU/WhUtJl2Pg9fVlcduhh+v51s9lSl1lbVDYev7GSFyl1dsklHTRzDAWnqKoy28oWoGT6iS7hDhGZOODSCU8xZWbwFAMXw+y13coXc4onDtlzzcuwd+v0/tHfo3u3saBp8XV935OL/9ddfRR6/uJIkrQ0J/xlvBSdFDTkumJ9MVq2LfGKGosB+qeTU+aRAR6/l5OPleEtRmJ3Pv9wtFp+ParX5YbW6MEu/u0RoPwjM6ucGQmbxg7uzOOXpaNp7uZ0UTnwU7dPpkywvXrmJK0hzc+OR/gXi+X69rhtzcwMcLBw0GqeGAPv1Ovw2GkFLbmlxs8B16UjeBpDNt5MGG61zhgOHzeZj1OGwxXYviXvB+OzuKuSrX/ulkrBdWDMWj02EdolWDH8hptV3821zUx1WKk/xMpIViy3b6fSrYbW6wDKZxb1y+dmPfJ2dbLbi1qBkckA7hXGGTQJ9Xxe5xQ0eI33YbDqWzVkmAz1dh3YoBDLJmOHwSQUnEa7h90NP1wFbXZE/ds5lp/Mmsu4jJK3x9LO/Vy4/88Ib2PfB4N6oVpvv6frSViSytl8qiYtfFv/5mXyQRWR2Rwnt+2BwD1tOMxz+ME1l+qhWm9/JZivDanUByUU+aCtVU2xSGuykKkVOV0USkdvP74OBYyAwKQ76Iq0JRfi9ctlp3ZCIEieK6BNzZKJJupadzzuqQhFRffYRlDN9c7vF4nOu3bGdbLbiFff70crKo2G1umCN16jwzReGlYpYr8P9YGozSUNDr5m4pDQNjwejZUa1msMGMUE0FyRz0R1IR6yObH3w+UTFxgnpvxuK8sn9vWRCOy/V1eHQ5+Qj63VWLCaqYcwTc6TKIqH5/dANBh062pnn6qS0j/OGA7dxVOTPTN23IpE1PpSCo5UVUY21VRXsfP7lfr2u31UjLBHaOXoEN89CT9eXfjSC+VoGFDzPXo5sdkTnSNWSOyzQ+AHRXsTq8BYSqzQktMNm8y+8Ovznr+vr/6U1PuUm1o9Qd2tdoNGIAYQ7QoiTp0xSfBf0hADdKbVzcwPZKjMxGdfnO0ni8Pn6XpZA+Ik8hm+0u8UifB8MwPTYjjAR2i2iPY76QU1i46bbkWPDuI9LzWY4LNovKxYTOhTaDeT2TVRR6Pe6wFph5/MvBUH6fMIHhgTa03WHHtfT9fHHcLvEdiJx8v3PmSqKYx/udvXkWIljomhI8TuOj+cEKBP1brH43BGpLRl1se30WvDgqFab7waDLVnkN8NhsPN5sNNpwNOGVjz+blYy/InQbmDFiZ/mgpuOFhZ2B/5ilsV5O5cr8XuNnzCSh4cknqrcLrJWDKvVBTwI4o7J7mja/2mHQv9Xskl8cuhaSJw+nyCl87YlhO/NRWgY8igTolid8vnGV+FTKUdlKlfNckuLVeqwUoFuMNiyYrFlr5AZXoLqplKv+9HoshTVA7vF4tgL6fNBPxpdpmqMCO3ScBPaRdXOVcFOp19NevGjfUGe8vWj0WVsrWRnPepHrQse95fV1YcOYZ1XfNxC8W+uquGfDSQ1/Ni5uZPvO66ePpxHnnKlJZNnPxo9tW4kFtyluO6zDgyLpXOuNR42m4+9IogPq9WFg0bjicntQluRCHSDQfFnj+tj3VTqtZc0PyK0KQOPUhmnpabTYN7QAYvW2BQ5caLYUhRHu8UniMx9X7Kn60tWPP7uR6qT1ngX1UGch80mWin+sl+vy3n/nybE7UBP12FUqwGSy1l2E9QDu6mUiBCSv5Z8vQk3DRzrV34/WPH4KfI7bDYft1V1wyvV2JfV1YeYnYfyBlZiOPjB+Km2qm6Q7YII7Up0LLRwbCcSMEgmrz2FQWSJcXOr/GLH6aZbz5MIjeF08zLEKw8GkDRxCumu1A6bzb8YivLJvczOCgX4sroKdi53rmaFlZRD65O+jnsHUzqJd6ql9mJaKhq3uQlWzs2DbiAgbBdbkciancuVSB8jQrtS8OV0sLiT3jzHfX6FhOZMY0XS4IK9O0mCZTKLf+YArbysbcVi8GV1FfbrdZk8PrkI8H+5o68dqR3neNMOm83HaD85417nqXUj9xSzNc6fW/aKbwwvx+8Wi897ur6EJLYViQgC6waDYjPFzuVK5B8jQrs+C0cstoytZ2+cC9a6zi2AFp9s7mSzjohpOZf+KluQL6urD5Fkvg8GQn+Tpqufvm1u+lxVmmMf04rHnfuU5/jg5IpL/hpS8oWjZT1oNJ60MMbaAwd35WpsKxJZ42mvYPI1L7yr0E2lHDcmSOgnQrux4QB/Bx2nqF7zybHWBE1MHOc9Ecjf7tfr+lW9uI8N4z4mxoppoqRd7ZdKj45WVv5bN5X6N8Pv/w939djT9ZM2UkqrmPT4eELuidUkGHS0kzvZbMVN2F7RxjDJ2HSeeINhtQr9aBRYoQD79Tp6yNhWJLI2S7csidC8MIWqVJ7iwjqPELpWGwfXjSZqTO5TbmY4/AFPorFC4YWdy5WG1erC0crKo8sEFFqx2PIgmYSOpsEgmXQsiMvTU4zSFtUYt2zY6TQ4BhkS8U4cDvj9Fg4FzHDYfVCYnRfQOK0ufqy0tiIRsVSPb4QWz37DY7xXdV2KQIT2p7U0JLSzVmqu4l2+p+tLp8gDzZW5nKhoRHgi5rZJLSqen+tHoxd6sexcrtTRNHHYt5tKCTe/TF5uwuqmUqJFtXM5p+mXk9Mkba8dCn3CxXT82lY8/q4fjS57RezHagyj15G8OpomtLHtRMIRBnrROhqBCO1mEl4zmUVcAO9o2jg99RpXoiRflSAHJKu2qjrOv8ntm4jm4UQkX+fuBoOts4iNJ12MKzPZNCvZJeR20orHoR0KObUzOUrbFflzTnwPMzwmhB8bxv1+NLpsjklKVGHDSgVwWVxeS+pHo8tXcXSFQIR2pSkc/AoO7BaL6Fx/9aNRPT8zjEAtDbUpKxYTEdN2Pg92Lif7zuDU7qNsdeCrSmdlhGEUjyAivgEgWs9xBeVoCxGYcDtpcR1vZU4if+Oatcgrn1Tm8y97qrrR0bT3e+UydFMpYJmMIDSsxrqBgDj7Rv4xIrTpHQ7EYsv4ztsNBNDacG1aGt9RZPLiOCsURKUmk5hsjD11EVxeCD/HUmH4fH0RuS0fTMGtAP657VDoExLRfr2u93R9Caey7ooRr0W1PBoweNBoPMFqDCsvvPiOhIarW6aisJ6qbgwrlafk5idC88QvdzcYbMlaybBSeXqdusheufxsKxJZkxNVZW2LFQoiVsexGsSXvsXCNjfp8mpvouiOF893stlTFZ9EmOysHU20I2BLjpUlt6F88JI2NqrV5uVJJVpMMKrHcYQ3HP7AMplFLxp9CXeY0OT9TinVFn4kTPHPtjsYqdOSKjbUshzDANdUdOIJuTOW1nkihhg2nFH1Mbd7XSyS8489aDRgVKvNt3hL6ZVp3mGz+RgtF/imZfJqHH2I/M9lHATY6fQraiuJ0Dy/32nn8zKpVW7q3fnYMO4fNpuPDxqNJzvZbKWjae/NcPjDViSyhitLskhvp9PiaK+cl9YOhU5FjLuvIbVV1bF4jp87qSJFQmspCvPSMRkMeewGgy2T64FYiaG0gFYdvii+gZenqK0kQpud/c54XD5AATeVxHHe0OLr+vr4QpKUCeYw5p6+Y3mqfcQDxDhMEIMASZeblKgxrFYXvFStoBesxxfD7VwODhoNYRDG9SR5Wml5aIhBIEL7M5406Eejy7f5Yj5aWXn0DwBAuA24kzApR5+no2I+mfNI8AUbAF6pxlAbM+bmRBuJa0nHhiGTmJhW0pI4EdrMgl+GYrhgjO/m12XhOK8qQ/2KHwOBv//xB/z9jz/g97/9zdFeivNzvELbLRZhJ5s9dR3ccRpuUoUn5Y15ysUfiy3zewVioIO7uYbPN04m1nX4bTSCbiBg9FR1Y1SrzVNbSYR2J9ANBAwp/FG8m9/EC+DL6urDbir1ujXOypK1LfgHAPz+++/wDwCRmIFE1o9GoafrcGwYYl8T9SD5a7dVdUNuW3eyWeDfa+O8RNpprMawVTT56tGxYYAVi4kEWOmQNOwWi8/pUhLhThIanhGzpCkYtp7X+T1ZofBCXl63YjFxbdxQFPjbf/4n/P777/D3P/44Od7LLR+sUIDfPn8+VXFN2lJAja3FY7W9oo0draw84gZoMansBoOASbDDahVYoSCmuEh4LJNZJCIj3FlCc1s4ePsGpitJ9SorjpaiMFzolg2seNGcX2lyVGktibyODQPcF54mOfjx0pRX4my+Dwb39srlZ5bkG9vJZqGnqiI8UfaNHTabYFJkD4EIzbXQnc+/dLQtwSCwTMYRI32VQMHefeGIZTJiGtlWVfj9b3+DfwDA1/V1aDljucX5ObRYTCJfr1QqRysrjwbJ5Bts/0UCrK47rRdS4oX1E4m+BCK0O4Fvm5sqVgT47t8NBE75u656v1NsDbhXnKRNAnnKKZ++M/x+2C0WofUDh4intRrDOCfZxd9WVdH6s0IB5L/HjyUiIxChXYBBMvkGCQ2nZqaisOuaePaj0WVHMizmpOXzjpBErNh2slk4WllxnLnrplKvb9s39zODEB5fzVx2GXkhXPzdViQCPA3jDbWVBCK0S1gCuoGAYcXjsJPNwiCZFNd6rs0yIh81OYmtPuU9G9VqMKrVxOYAnorzUmU2rFSedjTtPS6HO1aSJNFfCt4EzOWnlSQCEdoV7HfyKJm313XEgxUKLwz5vBtfS8K2ssUtCq5DJ8y4poHFdbTWLJNZROG+m0q5dTCw+FV1Kx4HY25OiPyUdEEgQruaFI5TL7jrbHU6mvbe8Pstd7iioSjw22gEX1ZXx+foQqFPW5HImhcCBke12rxsh5kEOXOso2nvB8nkGzTN0ouQQIR2RUK1yS81uWO6r7NaGFarC46bApnMIkbftEOhT6xQeDHtIvixYdw/Wll5JFVYkyaTp57XbiBgUJw1gQjtujYHUqnX3UBAiNTi2s813R2YRKpeMybzxXD2119/Bfn2qfs5tFxx1rQgTiBCuwHdB93pmCvPWyODfjlOnqOdbLYiByfa6fR4FYvHMXWDQThoNMTzd2wY9zua9p6uJBGI0G66SgsGW1hl4I6nOSEQ8a5hVKvNy76xjqaJqeQgmYTdYhG+rK6CyW0mfC1pzfJobDeBCG3WXrhj+4auiwDIu1qNyUSGK1p75TJsJxKym58dG8Z9HAiwTGaRiIxAhDZlFg75BXtX/v379breU9UNc6x3CbMxLojLSbAiHPOaVsUIBCK0K9jv7AYC4gXLp3Weyg/7mRUwPLgrE3o/GhVXnyYJ/JjJT+tIBCK0KbYhmNKLWgRA6vrSLFZjsovflFbAeP4+bEUi0E2lxFqSSZNKAhGat8C1I3dsDZulakxMKuNxRzuJefwu6wXrplKv7Xz+JWljBCI0j1dpvfH1pCUvt50HjcaTnqpu9FR1A936/LguDJJJ6GgatFUVzHBYJjO2FYms0XI4gQjN6+1YqfSLWzfy2rTz2+amygqFF25tbCebFRE9E0ywDJfDyTdGIEKbIX1pr1x2T/U80XZ+WV19iHn83WAQhpXK+IgIT381eYjiIJl0EJlXdkYJBCK0n9zvdFcv06ohHRvGfTuffym7+LcTCeimUuOUW26EdWtjJgUnEojQ7oiFI51+Jeto1hlXx28Th83mY0femOQPk9tL6e+Zya+jz7IVhUCgJ2GCW54fqhWEcJ1XoS6jjeFREXki29E0dxuJJAwm18W8csaOQCBCuwbwnUSweLqseYs62tHKyiMrHn8nt8J2Lud08AeD4zRYrvnhZSRqKQlEaARlv17XXfc72XUl2Z6ljcmTSpbJnOhgsZgQ/OWW0uJZ/Df5OAkEIjSPwD0c2C+VfrkJbcyKxZb3yuVn7tUj3F5AP5k1Pqryzk6nX9GUkkAgQrswhWMrEoGeqsIgmbw2HW3SwV2cTO4Wi47hBNfM3m9FImvDSuUptZQEAhHapTYH7Hz+Wi5CHa2sPOITVcarrTOz+NGW4YV4bgKBCG1KsZ1IvJWMtn/61sD3weDebrH4fNJREXNCsgVONGmXkkAgQruSKqofjS4jyfysh+vr+vqDbir1GnW5nq6Pc9diMWCZjBzVI0iMLiIRCERo11Kl/ZkTd3hUxN1Otk9WklhH097buVyJSIxAIEK7di2NDwjW9srlZ5dtMXu6vnS0siKmlFiJtVV1Y7dYfE7tJIFAhOaZ3VBD8ogNksk3o1ptnq6EEwhEaJ5dpaJIHgKBCI1AIBCI0AgEAhEagUAgEKERCAQCERqBQCAQoREIBAIRGoFAIEIjEAgEIjQCgUAgQiMQCAQiNAKBQIRGIBAIRGgEAoFAhEYgEAhEaAQCgTAR/38At8eLW1ub40wAAAAASUVORK5CYII="
window.addEventListener('load', e => {
// Ensuring height of image is always 100px
let pngWidth = png.width
let pngHeight = png.height
let divisor = pngHeight / 100
let finalWidth = pngWidth / divisor
let finalHeight = pngHeight / divisor
ctx.drawImage(png, 0, 0, finalWidth, finalHeight)
drawImage(finalWidth, finalHeight)
})
#canvas1 {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
<canvas id="canvas1"></canvas>
UPDATE 2: I have managed to optimize further. Now it can render FullHD image (1920x1080) without downgrading quality (on my PC it runs at about 20fps).
Take a look this code on JSFiddle (you can also tweak values).
Thanks also goes to #Richard (check out his answer) for idea to put all data in ImageData and make a single draw call. Code on JSFiddle is combination of his and mine optimizations (code below is my old code).
EDIT: Updated JSFiddle link, optimized more by spreading work of stationary particles across multiple frames (for given settings it improves performance for about 10%).
Regarding optimization, you won't achieve much by minifying code (in this case) because code that eats up CPU is runtime intensive (executes each frame). Minification is good for optimizing loading, not runtime execution.
Most of time is spent on drawing, and after some investigation I have found few performance optimizations but these are not enough to make big difference (eg. ctx.closePath() can be omitted and this saves some milliseconds).
What you can do is to either reduce resolution of image or skip some pixels in image in order to reduce work.
Additionally you could spread work across multiple frames to improve frame rate (but keep in mind if you spread it on more than few frames you might start seeing flickering).
Fullscreen issue can be solved by simply re-initializing everything on resize event.
Below is code with mentioned optimizations and fullscreen fix. Sample image is 375x375 pixels.
UPDATE: I played a little with code and I managed to improve further performance by optimizing calls (things I mentioned below code snippet). Code is updated with these changes.
var canv
var ctx
//performance critical parameters
const pixelStep = 2 //default 1; increase for images of higher resolution
const maxParticlesToProcessInOneFrame = 20000
//additional performance oriented paramteres
// Max distance, past that the force will be 0
const maxDistance = 144
const mouseRadius = 74
//customization parameters
const ctxFillStyle = 'rgba(0,0,0,.07)'
const speedOfActivatingParticle = 1
const speedOfRestoringParticle = 0.1
const png = new Image();
const mouse = {
x: null,
y: null
}
window.addEventListener('mousemove', (e) => {
mouse.x = event.x + canv.clientLeft;
mouse.y = event.y + canv.clientTop;
})
class Particle {
constructor(x, y, size) {
this.x = x
this.y = y
this.size = pixelStep
this.baseX = x
this.baseY = y
this.density = (Math.random() * 14) + 2
}
draw() {
//ctx.beginPath(); // this creates the sort of force field around the mouse pointer.
//ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);
ctx.rect(this.x, this.y, this.size * 2, this.size * 2)
//ctx.closePath();
}
update() {
// Collision detection
let dx = mouse.x - this.x;
let dy = mouse.y - this.y;
let distance = Math.sqrt(dx * dx + dy * dy);
if (distance < mouseRadius + this.size) {
let forceDirectionX = dx / distance;
let forceDirectionY = dy / distance;
let force = (maxDistance - distance) / maxDistance;
if (force < 0)
force = 0;
const forceTimesDensity = force * this.density * speedOfActivatingParticle
let directionX = (forceDirectionX * forceTimesDensity);
let directionY = (forceDirectionY * forceTimesDensity); //Ch.this
this.x -= directionX;
this.y -= directionY;
} else {
if (this.x !== this.baseX) {
let dx = this.x - this.baseX;
this.x -= dx * speedOfRestoringParticle; // Speed Particles return to ori
}
if (this.y !== this.baseY) {
let dy = this.y - this.baseY;
this.y -= dy * speedOfRestoringParticle; // Speed Particles return to ori
}
}
this.draw();
}
}
window.addEventListener('resize', initializeCanvas)
window.addEventListener("load", initializeCanvas, {
once: true
})
let animationFrame = null
function initializeCanvas(e) {
cancelAnimationFrame(animationFrame)
canv = document.getElementById('Canv');
ctx = canv.getContext('2d');
canv.width = window.innerWidth;
canv.height = window.innerHeight;
let particles = {}
function drawImage() {
let imageWidth = png.width; //These to values crop if / sum no.
let imageHeight = png.height;
const data = ctx.getImageData(0, 0, imageWidth, imageHeight); //Gets img data for particles
ctx.clearRect(0, 0, canv.width, canv.height); // Clears the original img as its now being stored in the variable data.
function init() {
particles = {}
for (let y = 0, y2 = data.height; y < y2; y += pixelStep) {
for (let x = 0, x2 = data.width; x < x2; x += pixelStep) {
if (data.data[(y * 4 * data.width) + (x * 4) + 3] > 128) {
let positionX = x
let positionY = y
let color = "rgb(" + data.data[(y * 4 * data.width) + (x * 4)] + "," +
data.data[(y * 4 * data.width) + (x * 4) + 1] + "," +
data.data[(y * 4 * data.width) + (x * 4) + 2] + ")";
let particlesArray = particles[color]
if (!particlesArray)
particlesArray = particles[color] = []
particlesArray.push(new Particle(positionX * 2, positionY * 2))
} /* These number effect png size but its to high */
}
}
}
let particlesProcessed = 0
let animateGenerator = animate()
function* animate() {
particlesProcessed = 0
ctx.fillStyle = ctxFillStyle;
ctx.fillRect(0, 0, innerWidth, innerHeight);
let colors = Object.keys(particles)
for (let j = 0; j < colors.length; j++) {
let color = colors[j]
ctx.fillStyle = color
let particlesArray = particles[color]
ctx.beginPath()
for (let i = 0; i < particlesArray.length; i++) {
particlesArray[i].update()
if (++particlesProcessed > maxParticlesToProcessInOneFrame) {
particlesProcessed = 0
ctx.fill()
yield
ctx.beginPath()
}
}
ctx.fill()
}
}
init();
function animateFrame() {
animationFrame = requestAnimationFrame(() => {
if (animateGenerator.next().done) {
animateGenerator = animate()
}
animateFrame()
})
}
animateFrame()
}
console.log('page has loaded');
ctx.drawImage(png, 0, 0, png.width, png.height);
drawImage();
}
png.src = 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";
body {
margin: 0;
padding: 0;
}
#Canv {
width: 100vw;
height: 100vh;
filter: blur(1.5px);
}
<canvas id="Canv"></canvas>
If you still need to optimize, you could do some optimization regarding ctx.beginPath(), ctx.fill() and ctx.rect() calls. For example, try to combine sibling pixels (pixels that are next to each other) and render them all in one call. Furthermore, you could merge similar colors in single color, but downside is that image will loose quality (depending on how much colors are merged).
Also (if this is option) you might want to set fixed canvas size rather than dynamically sized.
Disclosure: On my PC given code works nicely, but on others it might still have performance issues. For that reason try to play with pixelStep and maxParticlesToProcessInOneFrame variable values.

How to create animated chart (moving plot) using pure javascript?

I need to create animated chart with moving camera without using any jquery plugin. I need to write code from scratch, I can use only jquery, no plugins.
I had managed to write code that draws chart. The only problem is how to move viewport (camera) simultaneously with chart?
I understand that I need to use translate method. But I don't how to use it correctly.
Idea of chart that I need to create:
Link to codepen:
http://codepen.io/sigmaray/pen/EyKNmK
My code:
$(function() {
// Settings
CAN_WIDTH = 300;
CAN_HEIGHT = 300;
CAN_COLOR = "#ccc";
LINE_HEIGHT = 1;
INTERVAL = 50;
$DIV = $("#container");
lineX = 0;
lineY = CAN_HEIGHT / 2;
ctx = null;
randomNum = function(max, min) {
if (min == null) {
min = 0;
}
return Math.floor(Math.random() * (max - min) + min);
};
createCanvas = function() {
canvas = document.createElement('canvas');
canvas.width = CAN_WIDTH;
canvas.height = CAN_HEIGHT;
ctx = canvas.getContext('2d');
$DIV.append(canvas);
};
timerAnimation = function(callback) {
window.setTimeout(callback, INTERVAL);
};
anim = function() {
if (lineX > CAN_WIDTH) {
lineX = 0;
}
if (lineX === 0) {
ctx.fillStyle = CAN_COLOR;
ctx.fillRect(0, 0, CAN_WIDTH, CAN_HEIGHT);
}
oldLineX = lineX;
oldLineY = lineY;
lineY = randomNum(CAN_HEIGHT * (2 / 3), CAN_HEIGHT / 3);
xOffset = randomNum(10, 1);
lineX += xOffset;
ctx.beginPath();
ctx.lineWidth = LINE_HEIGHT;
ctx.moveTo(oldLineX, oldLineY);
ctx.lineTo(lineX, lineY);
ctx.stroke();
// !!! Doesn't work as expected !!!
// ctx.translate(xOffset, 0)
// ctx.save();
};
drawingCycle = function() {
anim();
timerAnimation(drawingCycle);
};
createCanvas();
drawingCycle();
});

Acceleration setInterval in Jquery

I am trying to create a bouncing ball (on a canvas). I would love if the ball could accelerate when going up and down. No idea how to do this with setInterval. Here is my code:
setInterval(function animate() {
ctx.clearRect( 0, 0, canvas.width, canvas.height);
if (movement1 === true) {
dotHeight += 1;
if (dotHeight >= 100) movement1 = false;
} else {
dotHeight -= 1;
if (dotHeight <= 0) movement1 = true;
}
ctx.beginPath();
ctx.arc(canvas.width / 2, (canvas.height / 2) + dotHeight, dotSize, 0, 2 * Math.PI);
ctx.fillStyle = "white";
ctx.fill();
}, 4);
This results in a linear movement. I would love to have a natural movement. Basically starting fast and getting slower when reaching the top and vice versa.
You should have both a speed and a gravity (or acceleration) variable:
speed tells you how many units (pixels here) is going to travel your object in the current update.
gravity tells you by how many units is speed increased on each update.
You want a constant gravity so that speed is increasing the same amount of pixels on each update. That will give you a variable speed, so that your object (dot here) is travelling longer or shorter distances on each update, depending on the direction it is travelling.
To make the dot bounce just change the direction of its speed once it reaches the floor. You just need to multiply it by -1 or, instead of that, you could multiply it by a bouncingFactor (-1 < bouncingFactor < 0) so that it loses energy on each bounce:
Here you can see a working example:
var canvas = document.getElementById("canvas");
canvas.width = canvas.offsetWidth;
canvas.height = canvas.offsetHeight;
var ctx = canvas.getContext("2d");
var frames = 0; // Frame counter just to make sure you don't crash your browser while editing code!
// DOT STUFF:
var dotSize = 20;
var dotMinY = 0 + dotSize; // Start position
var dotMaxY = canvas.height - dotSize; // Floor
var dotY = dotMinY;
var dotSpeed = 0;
var dotLastBounceSpeed = 0; // You can use this to determine whether the ball is still bouncing enough to be visible by the user.
var center = canvas.width / 2; // Try to take every operation you can out of the animate function.
var pi2 = 2 * Math.PI;
// WORLD STUFF:
var gravity = .5;
var bounceFactor = .8; // If < 1, bouncing absorbs energy so ball won't go as high as it was before.
// MAIN ANIMATION LOOP:
function animate() {
ctx.clearRect( 0, 0, canvas.width, canvas.height);
ctx.beginPath();
ctx.arc(center, dotY, dotSize, 0, pi2);
ctx.fillStyle = "red";
ctx.fill();
// First, dotSpeed += gravity is calculated and that returns the new value for dotSpeed
// then, that new value is added to dotY.
dotY += dotSpeed += gravity;
if(dotY >= dotMaxY ) {
dotY = dotMaxY;
dotSpeed *= -bounceFactor;
}
var dotCurrentBounceSpeed = Math.round(dotSpeed * 100); // Takes two decimal digits.
if(frames++ < 5000 && dotLastBounceSpeed != dotCurrentBounceSpeed) {
dotLastBounceSpeed = dotCurrentBounceSpeed;
setTimeout(animate, 16); // 1000/60 = 16.6666...
}
else alert("Animation end. Took " + frames + " frames.");
}
animate();
html, body, #canvas {
position:relative;
width: 100%;
height: 100%;
margin: 0;
overflow:hidden;
}
<canvas id="canvas"></canvas>
You should also consider using requestAnimationFrame insted of setTimeout. From the MDN doc:
The Window.requestAnimationFrame() method tells the browser that you
wish to perform an animation and requests that the browser call a
specified function to update an animation before the next repaint. The
method takes as an argument a callback to be invoked before the
repaint.
The same example with requestAnimationFrame:
var canvas = document.getElementById("canvas");
canvas.width = canvas.offsetWidth;
canvas.height = canvas.offsetHeight;
var ctx = canvas.getContext("2d");
var frames = 0; // Frame counter just to make sure you don't crash your browser while editing code!
// DOT STUFF:
var dotSize = 20;
var dotMinY = 0 + dotSize; // Start position
var dotMaxY = canvas.height - dotSize; // Floor
var dotY = dotMinY;
var dotSpeed = 0;
var dotLastBounceSpeed = 0; // You can use this to determine whether the ball is still bouncing enough to be visible by the user.
var center = canvas.width / 2; // Try to take every operation you can out of the animate function.
var pi2 = 2 * Math.PI;
// WORLD STUFF:
var gravity = .5;
var bounceFactor = .8; // If < 1, bouncing absorbs energy so ball won't go as high as it was before.
// MAIN ANIMATION LOOP:
function animate() {
ctx.clearRect( 0, 0, canvas.width, canvas.height);
ctx.beginPath();
ctx.arc(center, dotY, dotSize, 0, pi2);
ctx.fillStyle = "red";
ctx.fill();
// First, dotSpeed += gravity is calculated and that returns the new value for dotSpeed
// then, that new value is added to dotY.
dotY += dotSpeed += gravity;
if(dotY >= dotMaxY ) {
dotY = dotMaxY;
dotSpeed *= -bounceFactor;
}
var dotCurrentBounceSpeed = Math.round(dotSpeed * 100); // Takes two decimal digits.
if(frames++ < 5000 && dotLastBounceSpeed != dotCurrentBounceSpeed) {
dotLastBounceSpeed = dotCurrentBounceSpeed;
//setTimeout(animate, 10);
window.requestAnimationFrame(animate); // Better!!
}
else alert("Animation end. Took " + frames + " frames.");
}
animate();
html, body, #canvas {
position:relative;
width: 100%;
height: 100%;
margin: 0;
overflow:hidden;
}
<canvas id="canvas"></canvas>
As you can see, you only need to change one line of code! However, you may need a polyfill so that you fall back to setTimeout if the browser does not support requestAnimationFrame.
You can learn more about requestAnimationFrame in this post. It explains the basics and also how to set a custom frame rate.
The basic principle is to use a velocity variable as opposed to a constant height increment. So instead of dotHeight += 1 or dotHeight -= 1 you would do dotHeight += dotVelocity, where you define dotVelocity, and subtract it by a constant value (gravity) whenever the ball is in the air.
var dotHeight = 0;
var dotVelocity = 3; // start out moving up, like in your example
var gravity = .1; // you can adjust this constant for stronger/weaker gravity
setInterval(function animate() {
ctx.clearRect( 0, 0, canvas.width, canvas.height);
if (dotHeight > 0) { // if it hit the ground, stop movement
dotVelocity -= gravity;
dotHeight += dotVelocity;
}
ctx.beginPath();
ctx.arc(canvas.width / 2, (canvas.height / 2) + dotHeight, dotSize, 0, 2 * Math.PI);
ctx.fillStyle = "white";
ctx.fill();
}, 4);
You could use a speed variable instead of the constant 1 to determine how "far" to move the ball, like this:
var speed = 1;
setInterval(function animate() {
ctx.clearRect( 0, 0, canvas.width, canvas.height);
if (movement1 === true) {
dotHeight += speed;
if (dotHeight >= 100) movement1 = false;
// make it faster
speed += 1;
} else {
dotHeight -= speed;
if (dotHeight <= 0) movement1 = true;
// slow down
speed -= 1;
}
ctx.beginPath();
ctx.arc(canvas.width / 2, (canvas.height / 2) + dotHeight, dotSize, 0, 2 * Math.PI);
ctx.fillStyle = "white";
ctx.fill();
}, 4);

HTML Canvas Full Screen

I'm playing with the following application using the HTML Canvas: http://driz.co.uk/particles/
At the moment it is set to 640x480 pixels, but I would like to make it full screen as it will be shown a projector. However as far as I can tell I cannot set the canvas size to be 100% as the variables only except numbers and not the %. Using CSS just stretches it rather than making it actual full screen.
Any ideas?
EDIT: Tried finding the height and width using jQuery but it breaks the canvas any ideas why?
var $j = jQuery.noConflict();
var canvas;
var ctx;
var canvasDiv;
var outerDiv;
var canvasW = $j('body').width();
var canvasH = $j('body').height();
//var canvasW = 640;
//var canvasH = 480;
var numMovers = 550;
var movers = [];
var friction = .96;
var radCirc = Math.PI * 2;
var mouseX, mouseY, mouseVX, mouseVY, prevMouseX = 0, prevMouseY = 0;
var isMouseDown = true;
function init()
{
canvas = document.getElementById("mainCanvas");
if( canvas.getContext )
{
setup();
setInterval( run , 33 );
}
}
function setup()
{
outerDiv = document.getElementById("outer");
canvasDiv = document.getElementById("canvasContainer");
ctx = canvas.getContext("2d");
var i = numMovers;
while( i-- )
{
var m = new Mover();
m.x = canvasW * .5;
m.y = canvasH * .5;
m.vX = Math.cos(i) * Math.random() * 25;
m.vY = Math.sin(i) * Math.random() * 25;
m.size = 2;
movers[i] = m;
}
document.onmousedown = onDocMouseDown;
document.onmouseup = onDocMouseUp;
document.onmousemove = onDocMouseMove;
}
function run()
{
ctx.globalCompositeOperation = "source-over";
ctx.fillStyle = "rgba(8,8,12,.65)";
ctx.fillRect( 0 , 0 , canvasW , canvasH );
ctx.globalCompositeOperation = "lighter";
mouseVX = mouseX - prevMouseX;
mouseVY = mouseY - prevMouseY;
prevMouseX = mouseX;
prevMouseY = mouseY;
var toDist = canvasW / 1.15;
var stirDist = canvasW / 8;
var blowDist = canvasW / 2;
var Mrnd = Math.random;
var Mabs = Math.abs;
var Msqrt = Math.sqrt;
var Mcos = Math.cos;
var Msin = Math.sin;
var Matan2 = Math.atan2;
var Mmax = Math.max;
var Mmin = Math.min;
var i = numMovers;
while( i-- )
{
var m = movers[i];
var x = m.x;
var y = m.y;
var vX = m.vX;
var vY = m.vY;
var dX = x - mouseX;
var dY = y - mouseY;
var d = Msqrt( dX * dX + dY * dY );
var a = Matan2( dY , dX );
var cosA = Mcos( a );
var sinA = Msin( a );
if( isMouseDown )
{
if( d < blowDist )
{
var blowAcc = ( 1 - ( d / blowDist ) ) * 2;
vX += cosA * blowAcc + .5 - Mrnd();
vY += sinA * blowAcc + .5 - Mrnd();
}
}
if( d < toDist )
{
var toAcc = ( 1 - ( d / toDist ) ) * canvasW * .0014;
vX -= cosA * toAcc;
vY -= sinA * toAcc;
}
if( d < stirDist )
{
var mAcc = ( 1 - ( d / stirDist ) ) * canvasW * .00022;
vX += mouseVX * mAcc;
vY += mouseVY * mAcc;
}
vX *= friction;
vY *= friction;
var avgVX = Mabs( vX );
var avgVY = Mabs( vY );
var avgV = ( avgVX + avgVY ) * .5;
if( avgVX < .1 ) vX *= Mrnd() * 3;
if( avgVY < .1 ) vY *= Mrnd() * 3;
var sc = avgV * .45;
sc = Mmax( Mmin( sc , 3.5 ) , .4 );
var nextX = x + vX;
var nextY = y + vY;
if( nextX > canvasW )
{
nextX = canvasW;
vX *= -1;
}
else if( nextX < 0 )
{
nextX = 0;
vX *= -1;
}
if( nextY > canvasH )
{
nextY = canvasH;
vY *= -1;
}
else if( nextY < 0 )
{
nextY = 0;
vY *= -1;
}
m.vX = vX;
m.vY = vY;
m.x = nextX;
m.y = nextY;
ctx.fillStyle = m.color;
ctx.beginPath();
ctx.arc( nextX , nextY , sc , 0 , radCirc , true );
ctx.closePath();
ctx.fill();
}
//rect( ctx , mouseX - 3 , mouseY - 3 , 6 , 6 );
}
function onDocMouseMove( e )
{
var ev = e ? e : window.event;
mouseX = ev.clientX - outerDiv.offsetLeft - canvasDiv.offsetLeft;
mouseY = ev.clientY - outerDiv.offsetTop - canvasDiv.offsetTop;
}
function onDocMouseDown( e )
{
isMouseDown = true;
return false;
}
function onDocMouseUp( e )
{
isMouseDown = true;
return false;
}
// ==========================================================================================
function Mover()
{
this.color = "rgb(" + Math.floor( Math.random()*255 ) + "," + Math.floor( Math.random()*255 ) + "," + Math.floor( Math.random()*255 ) + ")";
this.y = 0;
this.x = 0;
this.vX = 0;
this.vY = 0;
this.size = 0;
}
// ==========================================================================================
function rect( context , x , y , w , h )
{
context.beginPath();
context.rect( x , y , w , h );
context.closePath();
context.fill();
}
// ==========================================================================================
The javascript has
var canvasW = 640;
var canvasH = 480;
in it. Try changing those as well as the css for the canvas.
Or better yet, have the initialize function determine the size of the canvas from the css!
in response to your edits, change your init function:
function init()
{
canvas = document.getElementById("mainCanvas");
canvas.width = document.body.clientWidth; //document.width is obsolete
canvas.height = document.body.clientHeight; //document.height is obsolete
canvasW = canvas.width;
canvasH = canvas.height;
if( canvas.getContext )
{
setup();
setInterval( run , 33 );
}
}
Also remove all the css from the wrappers, that just junks stuff up. You have to edit the js to get rid of them completely though... I was able to get it full screen though.
html, body {
overflow: hidden;
}
Edit: document.width and document.height are obsolete. Replace with document.body.clientWidth and document.body.clientHeight
You can just insert the following in to your main html page, or a function:
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
Then to remove the margins on the page
html, body {
margin: 0 !important;
padding: 0 !important;
}
That should do the job
The newest Chrome and Firefox support a fullscreen API, but setting to fullscreen is like a window resize. Listen to the onresize-Event of the window-object:
$(window).bind("resize", function(){
var w = $(window).width();
var h = $(window).height();
$("#mycanvas").css("width", w + "px");
$("#mycanvas").css("height", h + "px");
});
//using HTML5 for fullscreen (only newest Chrome + FF)
$("#mycanvas")[0].webkitRequestFullScreen(Element.ALLOW_KEYBOARD_INPUT); //Chrome
$("#mycanvas")[0].mozRequestFullScreen(); //Firefox
//...
//now i want to cancel fullscreen
document.webkitCancelFullScreen(); //Chrome
document.mozCancelFullScreen(); //Firefox
This doesn't work in every browser. You should check if the functions exist or it will throw an js-error.
for more info on html5-fullscreen check this:
http://updates.html5rocks.com/2011/10/Let-Your-Content-Do-the-Talking-Fullscreen-API
Because it was not posted yet and is a simple css fix:
#canvas {
position:fixed;
left:0;
top:0;
width:100%;
height:100%;
}
Works great if you want to apply a fullscreen canvas background (for example with Granim.js).
All you need to do is set the width and height attributes to be the size of the canvas, dynamically. So you use CSS to make it stretch over the entire browser window, then you have a little function in javascript which measures the width and height, and assigns them. I'm not terribly familliar with jQuery, so consider this psuedocode:
window.onload = window.onresize = function() {
theCanvas.width = theCanvas.offsetWidth;
theCanvas.height = theCanvas.offsetHeight;
}
The width and height attributes of the element determine how many pixels it uses in it's internal rendering buffer. Changing those to new numbers causes the canvas to reinitialise with a differently sized, blank buffer. Browser will only stretch the graphics if the width and height attributes disagree with the actual real world pixel width and height.
If you want to show it in a presentation then consider using requestFullscreen() method
let canvas = document.getElementById("canvas_id");
canvas.requestFullscreen();
that should make it fullscreen whatever the current circumstances are.
also check the support table https://caniuse.com/?search=requestFullscreen
On document load set the
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
A - How To Calculate Full Screen Width & Height
Here is the functions;
canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth;
canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
Check this out
B - How To Make Full Screen Stable With Resize
Here is the resize method for the resize event;
function resizeCanvas() {
canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth;
canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
WIDTH = canvas.width;
HEIGHT = canvas.height;
clearScreen();
}
C - How To Get Rid Of Scroll Bars
Simply;
<style>
html, body {
overflow: hidden;
}
</style>
D - Demo Code
<html>
<head>
<title>Full Screen Canvas Example</title>
<style>
html, body {
overflow: hidden;
}
</style>
</head>
<body onresize="resizeCanvas()">
<canvas id="mainCanvas">
</canvas>
<script>
(function () {
canvas = document.getElementById('mainCanvas');
ctx = canvas.getContext("2d");
canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth;
canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
WIDTH = canvas.width;
HEIGHT = canvas.height;
clearScreen();
})();
function resizeCanvas() {
canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth;
canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
WIDTH = canvas.width;
HEIGHT = canvas.height;
clearScreen();
}
function clearScreen() {
var grd = ctx.createLinearGradient(0,0,0,180);
grd.addColorStop(0,"#6666ff");
grd.addColorStop(1,"#aaaacc");
ctx.fillStyle = grd;
ctx.fillRect( 0, 0, WIDTH, HEIGHT );
}
</script>
</body>
</html>
I hope it will be useful.
// Get the canvas element
var canvas = document.getElementById('canvas');
var isInFullScreen = (document.fullscreenElement && document.fullscreenElement !== null) ||
(document.webkitFullscreenElement && document.webkitFullscreenElement !== null) ||
(document.mozFullScreenElement && document.mozFullScreenElement !== null) ||
(document.msFullscreenElement && document.msFullscreenElement !== null);
// Enter fullscreen
function fullscreen(){
if(canvas.RequestFullScreen){
canvas.RequestFullScreen();
}else if(canvas.webkitRequestFullScreen){
canvas.webkitRequestFullScreen();
}else if(canvas.mozRequestFullScreen){
canvas.mozRequestFullScreen();
}else if(canvas.msRequestFullscreen){
canvas.msRequestFullscreen();
}else{
alert("This browser doesn't supporter fullscreen");
}
}
// Exit fullscreen
function exitfullscreen(){
if (document.exitFullscreen) {
document.exitFullscreen();
} else if (document.webkitExitFullscreen) {
document.webkitExitFullscreen();
} else if (document.mozCancelFullScreen) {
document.mozCancelFullScreen();
} else if (document.msExitFullscreen) {
document.msExitFullscreen();
}else{
alert("Exit fullscreen doesn't work");
}
}
function resize() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
render();
}
window.addEventListener('resize', resize, false); resize();
function render() { // draw to screen here
}
https://jsfiddle.net/jy8k6hfd/2/
it's simple, set canvas width and height to screen.width and screen.height. then press F11! think F11 should make full screen in most browsers does in FFox and IE.
Well, I was looking to make my canvas fullscreen too, This is how i did it. I'll post the entire index.html since I am not a CSS expert yet : (basically just using position:fixed and width and height as 100% and top and left as 0% and i nested this CSS code for every tag. I also have min-height and min-width as 100%. When I tried it with a 1px border the border size was changing as I zoomed in and out but the canvas remained fullscreen.)
<!DOCTYPE html>
<html style="position:fixed;min-height:100%;min-width:100%;height:100%;width:100%;top:0%;left:0%;resize:none;">
<head>
<title>MOUSEOVER</title>
<script "text/javascript" src="main.js"></script>
</head>
<body id="BODY_CONTAINER" style="position:fixed;min-height:100%;min-width:100%;height:100%;width:100%;top:0%;left:0%;resize:none;">
<div id="DIV_GUI_CONTAINER" style="position:fixed;min-height:100%;min-width:100%;height:100%;width:100%;top:0%;left:0%;resize:none;">
<canvas id="myCanvas" style="position:fixed;min-height:100%;min-width:100%;height:100%;width:100%;top:0%;left:0%;resize:none;">
</canvas>
</div>
</body>
</html>
EDIT:
add this to the canvas element:
<canvas id="myCanvas" width="" height="" style="position:fixed;min-height:100%;min-width:100%;height:100%;width:100%;top:0%;left:0%;resize:none;">
</canvas>
add this to the javascript
canvas.width = window.screen.width;
canvas.height = window.screen.height;
I found this made the drawing a lot smoother than my original comment.
Thanks.
AFAIK, HTML5 does not provide an API which supports full screen.
This question has some view points on making html5 video full screen for example using webkitEnterFullscreen in webkit.
Is there a way to make html5 video fullscreen
You could just capture window resize events and set the size of your canvas to be the browser's viewport.
Get the full width and height of the screen and create a new window set to the appropriate width and height, and with everything disabled. Create a canvas inside of that new window, setting the width and height of the canvas to the width - 10px and the height - 20px (to allow for the bar and the edges of the window). Then work your magic on that canvas.

Resizing an image in an HTML5 canvas

I'm trying to create a thumbnail image on the client side using javascript and a canvas element, but when I shrink the image down, it looks terrible. It looks as if it was downsized in photoshop with the resampling set to 'Nearest Neighbor' instead of Bicubic. I know its possible to get this to look right, because this site can do it just fine using a canvas as well. I've tried using the same code they do as shown in the "[Source]" link, but it still looks terrible. Is there something I'm missing, some setting that needs to be set or something?
EDIT:
I'm trying to resize a jpg. I have tried resizing the same jpg on the linked site and in photoshop, and it looks fine when downsized.
Here is the relevant code:
reader.onloadend = function(e)
{
var img = new Image();
var ctx = canvas.getContext("2d");
var canvasCopy = document.createElement("canvas");
var copyContext = canvasCopy.getContext("2d");
img.onload = function()
{
var ratio = 1;
if(img.width > maxWidth)
ratio = maxWidth / img.width;
else if(img.height > maxHeight)
ratio = maxHeight / img.height;
canvasCopy.width = img.width;
canvasCopy.height = img.height;
copyContext.drawImage(img, 0, 0);
canvas.width = img.width * ratio;
canvas.height = img.height * ratio;
ctx.drawImage(canvasCopy, 0, 0, canvasCopy.width, canvasCopy.height, 0, 0, canvas.width, canvas.height);
};
img.src = reader.result;
}
EDIT2:
Seems I was mistaken, the linked website wasn't doing any better of a job of downsizing the image. I tried the other methods suggested and none of them look any better. This is what the different methods resulted in:
Photoshop:
Canvas:
Image with image-rendering: optimizeQuality set and scaled with width/height:
Image with image-rendering: optimizeQuality set and scaled with -moz-transform:
Canvas resize on pixastic:
I guess this means firefox isn't using bicubic sampling like its supposed to. I'll just have to wait until they actually add it.
EDIT3:
Original Image
So what do you do if all the browsers (actually, Chrome 5 gave me quite good one) won't give you good enough resampling quality? You implement them yourself then! Oh come on, we're entering the new age of Web 3.0, HTML5 compliant browsers, super optimized JIT javascript compilers, multi-core(†) machines, with tons of memory, what are you afraid of? Hey, there's the word java in javascript, so that should guarantee the performance, right? Behold, the thumbnail generating code:
// returns a function that calculates lanczos weight
function lanczosCreate(lobes) {
return function(x) {
if (x > lobes)
return 0;
x *= Math.PI;
if (Math.abs(x) < 1e-16)
return 1;
var xx = x / lobes;
return Math.sin(x) * Math.sin(xx) / x / xx;
};
}
// elem: canvas element, img: image element, sx: scaled width, lobes: kernel radius
function thumbnailer(elem, img, sx, lobes) {
this.canvas = elem;
elem.width = img.width;
elem.height = img.height;
elem.style.display = "none";
this.ctx = elem.getContext("2d");
this.ctx.drawImage(img, 0, 0);
this.img = img;
this.src = this.ctx.getImageData(0, 0, img.width, img.height);
this.dest = {
width : sx,
height : Math.round(img.height * sx / img.width),
};
this.dest.data = new Array(this.dest.width * this.dest.height * 3);
this.lanczos = lanczosCreate(lobes);
this.ratio = img.width / sx;
this.rcp_ratio = 2 / this.ratio;
this.range2 = Math.ceil(this.ratio * lobes / 2);
this.cacheLanc = {};
this.center = {};
this.icenter = {};
setTimeout(this.process1, 0, this, 0);
}
thumbnailer.prototype.process1 = function(self, u) {
self.center.x = (u + 0.5) * self.ratio;
self.icenter.x = Math.floor(self.center.x);
for (var v = 0; v < self.dest.height; v++) {
self.center.y = (v + 0.5) * self.ratio;
self.icenter.y = Math.floor(self.center.y);
var a, r, g, b;
a = r = g = b = 0;
for (var i = self.icenter.x - self.range2; i <= self.icenter.x + self.range2; i++) {
if (i < 0 || i >= self.src.width)
continue;
var f_x = Math.floor(1000 * Math.abs(i - self.center.x));
if (!self.cacheLanc[f_x])
self.cacheLanc[f_x] = {};
for (var j = self.icenter.y - self.range2; j <= self.icenter.y + self.range2; j++) {
if (j < 0 || j >= self.src.height)
continue;
var f_y = Math.floor(1000 * Math.abs(j - self.center.y));
if (self.cacheLanc[f_x][f_y] == undefined)
self.cacheLanc[f_x][f_y] = self.lanczos(Math.sqrt(Math.pow(f_x * self.rcp_ratio, 2)
+ Math.pow(f_y * self.rcp_ratio, 2)) / 1000);
weight = self.cacheLanc[f_x][f_y];
if (weight > 0) {
var idx = (j * self.src.width + i) * 4;
a += weight;
r += weight * self.src.data[idx];
g += weight * self.src.data[idx + 1];
b += weight * self.src.data[idx + 2];
}
}
}
var idx = (v * self.dest.width + u) * 3;
self.dest.data[idx] = r / a;
self.dest.data[idx + 1] = g / a;
self.dest.data[idx + 2] = b / a;
}
if (++u < self.dest.width)
setTimeout(self.process1, 0, self, u);
else
setTimeout(self.process2, 0, self);
};
thumbnailer.prototype.process2 = function(self) {
self.canvas.width = self.dest.width;
self.canvas.height = self.dest.height;
self.ctx.drawImage(self.img, 0, 0, self.dest.width, self.dest.height);
self.src = self.ctx.getImageData(0, 0, self.dest.width, self.dest.height);
var idx, idx2;
for (var i = 0; i < self.dest.width; i++) {
for (var j = 0; j < self.dest.height; j++) {
idx = (j * self.dest.width + i) * 3;
idx2 = (j * self.dest.width + i) * 4;
self.src.data[idx2] = self.dest.data[idx];
self.src.data[idx2 + 1] = self.dest.data[idx + 1];
self.src.data[idx2 + 2] = self.dest.data[idx + 2];
}
}
self.ctx.putImageData(self.src, 0, 0);
self.canvas.style.display = "block";
};
...with which you can produce results like these!
so anyway, here is a 'fixed' version of your example:
img.onload = function() {
var canvas = document.createElement("canvas");
new thumbnailer(canvas, img, 188, 3); //this produces lanczos3
// but feel free to raise it up to 8. Your client will appreciate
// that the program makes full use of his machine.
document.body.appendChild(canvas);
};
Now it's time to pit your best browsers out there and see which one will least likely increase your client's blood pressure!
Umm, where's my sarcasm tag?
(since many parts of the code is based on Anrieff Gallery Generator is it also covered under GPL2? I don't know)
† actually due to limitation of javascript, multi-core is not supported.
Fast image resize/resample algorithm using Hermite filter with JavaScript. Support transparency, gives good quality. Preview:
Update: version 2.0 added on GitHub (faster, web workers + transferable objects). Finally i got it working!
Git: https://github.com/viliusle/Hermite-resize
Demo: http://viliusle.github.io/miniPaint/
/**
* Hermite resize - fast image resize/resample using Hermite filter. 1 cpu version!
*
* #param {HtmlElement} canvas
* #param {int} width
* #param {int} height
* #param {boolean} resize_canvas if true, canvas will be resized. Optional.
*/
function resample_single(canvas, width, height, resize_canvas) {
var width_source = canvas.width;
var height_source = canvas.height;
width = Math.round(width);
height = Math.round(height);
var ratio_w = width_source / width;
var ratio_h = height_source / height;
var ratio_w_half = Math.ceil(ratio_w / 2);
var ratio_h_half = Math.ceil(ratio_h / 2);
var ctx = canvas.getContext("2d");
var img = ctx.getImageData(0, 0, width_source, height_source);
var img2 = ctx.createImageData(width, height);
var data = img.data;
var data2 = img2.data;
for (var j = 0; j < height; j++) {
for (var i = 0; i < width; i++) {
var x2 = (i + j * width) * 4;
var weight = 0;
var weights = 0;
var weights_alpha = 0;
var gx_r = 0;
var gx_g = 0;
var gx_b = 0;
var gx_a = 0;
var center_y = (j + 0.5) * ratio_h;
var yy_start = Math.floor(j * ratio_h);
var yy_stop = Math.ceil((j + 1) * ratio_h);
for (var yy = yy_start; yy < yy_stop; yy++) {
var dy = Math.abs(center_y - (yy + 0.5)) / ratio_h_half;
var center_x = (i + 0.5) * ratio_w;
var w0 = dy * dy; //pre-calc part of w
var xx_start = Math.floor(i * ratio_w);
var xx_stop = Math.ceil((i + 1) * ratio_w);
for (var xx = xx_start; xx < xx_stop; xx++) {
var dx = Math.abs(center_x - (xx + 0.5)) / ratio_w_half;
var w = Math.sqrt(w0 + dx * dx);
if (w >= 1) {
//pixel too far
continue;
}
//hermite filter
weight = 2 * w * w * w - 3 * w * w + 1;
var pos_x = 4 * (xx + yy * width_source);
//alpha
gx_a += weight * data[pos_x + 3];
weights_alpha += weight;
//colors
if (data[pos_x + 3] < 255)
weight = weight * data[pos_x + 3] / 250;
gx_r += weight * data[pos_x];
gx_g += weight * data[pos_x + 1];
gx_b += weight * data[pos_x + 2];
weights += weight;
}
}
data2[x2] = gx_r / weights;
data2[x2 + 1] = gx_g / weights;
data2[x2 + 2] = gx_b / weights;
data2[x2 + 3] = gx_a / weights_alpha;
}
}
//clear and resize canvas
if (resize_canvas === true) {
canvas.width = width;
canvas.height = height;
} else {
ctx.clearRect(0, 0, width_source, height_source);
}
//draw
ctx.putImageData(img2, 0, 0);
}
Try pica - that's a highly optimized resizer with selectable algorythms. See demo.
For example, original image from first post is resized in 120ms with Lanczos filter and 3px window or 60ms with Box filter and 0.5px window. For huge 17mb image 5000x3000px resize takes ~1s on desktop and 3s on mobile.
All resize principles were described very well in this thread, and pica does not add rocket science. But it's optimized very well for modern JIT-s, and is ready to use out of box (via npm or bower). Also, it use webworkers when available to avoid interface freezes.
I also plan to add unsharp mask support soon, because it's very useful after downscale.
I know this is an old thread but it might be useful for some people such as myself that months after are hitting this issue for the first time.
Here is some code that resizes the image every time you reload the image. I am aware this is not optimal at all, but I provide it as a proof of concept.
Also, sorry for using jQuery for simple selectors but I just feel too comfortable with the syntax.
$(document).on('ready', createImage);
$(window).on('resize', createImage);
var createImage = function(){
var canvas = document.getElementById('myCanvas');
canvas.width = window.innerWidth || $(window).width();
canvas.height = window.innerHeight || $(window).height();
var ctx = canvas.getContext('2d');
img = new Image();
img.addEventListener('load', function () {
ctx.drawImage(this, 0, 0, w, h);
});
img.src = 'http://www.ruinvalor.com/Telanor/images/original.jpg';
};
html, body{
height: 100%;
width: 100%;
margin: 0;
padding: 0;
background: #000;
}
canvas{
position: absolute;
left: 0;
top: 0;
z-index: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<html>
<head>
<meta charset="utf-8" />
<title>Canvas Resize</title>
</head>
<body>
<canvas id="myCanvas"></canvas>
</body>
</html>
My createImage function is called once when the document is loaded and after that it is called every time the window receives a resize event.
I tested it in Chrome 6 and Firefox 3.6, both on the Mac. This "technique" eats processor as it if was ice cream in the summer, but it does the trick.
I've put up some algorithms to do image interpolation on html canvas pixel arrays that might be useful here:
https://web.archive.org/web/20170104190425/http://jsperf.com:80/pixel-interpolation/2
These can be copy/pasted and can be used inside of web workers to resize images (or any other operation that requires interpolation - I'm using them to defish images at the moment).
I haven't added the lanczos stuff above, so feel free to add that as a comparison if you'd like.
This is a javascript function adapted from #Telanor's code. When passing a image base64 as first argument to the function, it returns the base64 of the resized image. maxWidth and maxHeight are optional.
function thumbnail(base64, maxWidth, maxHeight) {
// Max size for thumbnail
if(typeof(maxWidth) === 'undefined') var maxWidth = 500;
if(typeof(maxHeight) === 'undefined') var maxHeight = 500;
// Create and initialize two canvas
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
var canvasCopy = document.createElement("canvas");
var copyContext = canvasCopy.getContext("2d");
// Create original image
var img = new Image();
img.src = base64;
// Determine new ratio based on max size
var ratio = 1;
if(img.width > maxWidth)
ratio = maxWidth / img.width;
else if(img.height > maxHeight)
ratio = maxHeight / img.height;
// Draw original image in second canvas
canvasCopy.width = img.width;
canvasCopy.height = img.height;
copyContext.drawImage(img, 0, 0);
// Copy and resize second canvas to first canvas
canvas.width = img.width * ratio;
canvas.height = img.height * ratio;
ctx.drawImage(canvasCopy, 0, 0, canvasCopy.width, canvasCopy.height, 0, 0, canvas.width, canvas.height);
return canvas.toDataURL();
}
I'd highly suggest you check out this link and make sure it is set to true.
Controlling image scaling behavior
Introduced in Gecko 1.9.2 (Firefox 3.6
/ Thunderbird 3.1 / Fennec 1.0)
Gecko 1.9.2 introduced the
mozImageSmoothingEnabled property to
the canvas element; if this Boolean
value is false, images won't be
smoothed when scaled. This property is
true by default. view plainprint?
cx.mozImageSmoothingEnabled = false;
If you're simply trying to resize an image, I'd recommend setting width and height of the image with CSS. Here's a quick example:
.small-image {
width: 100px;
height: 100px;
}
Note that the height and width can also be set using JavaScript. Here's quick code sample:
var img = document.getElement("my-image");
img.style.width = 100 + "px"; // Make sure you add the "px" to the end,
img.style.height = 100 + "px"; // otherwise you'll confuse IE
Also, to ensure that the resized image looks good, add the following css rules to image selector:
-ms-interpolation-mode: bicubic: introduce in IE7
image-rendering: optimizeQuality: introduced in FireFox 3.6
As far as I can tell, all browsers except IE using an bicubic algorithm to resize images by default, so your resized images should look good in Firefox and Chrome.
If setting the css width and height doesn't work, you may want to play with a css transform:
-moz-transform: scale(sx[, sy])
-webkit-transform:scale(sx[, sy])
If for whatever reason you need to use a canvas, please note that there are two ways an image can be resize: by resizing the canvas with css or by drawing the image at a smaller size.
See this question for more details.
i got this image by right clicking the canvas element in firefox and saving as.
var img = new Image();
img.onload = function () {
console.debug(this.width,this.height);
var canvas = document.createElement('canvas'), ctx;
canvas.width = 188;
canvas.height = 150;
document.body.appendChild(canvas);
ctx = canvas.getContext('2d');
ctx.drawImage(img,0,0,188,150);
};
img.src = 'original.jpg';
so anyway, here is a 'fixed' version of your example:
var img = new Image();
// added cause it wasnt defined
var canvas = document.createElement("canvas");
document.body.appendChild(canvas);
var ctx = canvas.getContext("2d");
var canvasCopy = document.createElement("canvas");
// adding it to the body
document.body.appendChild(canvasCopy);
var copyContext = canvasCopy.getContext("2d");
img.onload = function()
{
var ratio = 1;
// defining cause it wasnt
var maxWidth = 188,
maxHeight = 150;
if(img.width > maxWidth)
ratio = maxWidth / img.width;
else if(img.height > maxHeight)
ratio = maxHeight / img.height;
canvasCopy.width = img.width;
canvasCopy.height = img.height;
copyContext.drawImage(img, 0, 0);
canvas.width = img.width * ratio;
canvas.height = img.height * ratio;
// the line to change
// ctx.drawImage(canvasCopy, 0, 0, canvasCopy.width, canvasCopy.height, 0, 0, canvas.width, canvas.height);
// the method signature you are using is for slicing
ctx.drawImage(canvasCopy, 0, 0, canvas.width, canvas.height);
};
// changed for example
img.src = 'original.jpg';
For resizing to image with width less that original, i use:
function resize2(i) {
var cc = document.createElement("canvas");
cc.width = i.width / 2;
cc.height = i.height / 2;
var ctx = cc.getContext("2d");
ctx.drawImage(i, 0, 0, cc.width, cc.height);
return cc;
}
var cc = img;
while (cc.width > 64 * 2) {
cc = resize2(cc);
}
// .. than drawImage(cc, .... )
and it works =).
I have a feeling the module I wrote will produce similar results to photoshop, as it preserves color data by averaging them, not applying an algorithm. It's kind of slow, but to me it is the best, because it preserves all the color data.
https://github.com/danschumann/limby-resize/blob/master/lib/canvas_resize.js
It doesn't take the nearest neighbor and drop other pixels, or sample a group and take a random average. It takes the exact proportion each source pixel should output into the destination pixel. The average pixel color in the source will be the average pixel color in the destination, which these other formulas, I think they will not be.
an example of how to use is at the bottom of
https://github.com/danschumann/limby-resize
UPDATE OCT 2018: These days my example is more academic than anything else. Webgl is pretty much 100%, so you'd be better off resizing with that to produce similar results, but faster. PICA.js does this, I believe. –
The problem with some of this solutions is that they access directly the pixel data and loop through it to perform the downsampling. Depending on the size of the image this can be very resource intensive, and it would be better to use the browser's internal algorithms.
The drawImage() function is using a linear-interpolation, nearest-neighbor resampling method. That works well when you are not resizing down more than half the original size.
If you loop to only resize max one half at a time, the results would be quite good, and much faster than accessing pixel data.
This function downsample to half at a time until reaching the desired size:
function resize_image( src, dst, type, quality ) {
var tmp = new Image(),
canvas, context, cW, cH;
type = type || 'image/jpeg';
quality = quality || 0.92;
cW = src.naturalWidth;
cH = src.naturalHeight;
tmp.src = src.src;
tmp.onload = function() {
canvas = document.createElement( 'canvas' );
cW /= 2;
cH /= 2;
if ( cW < src.width ) cW = src.width;
if ( cH < src.height ) cH = src.height;
canvas.width = cW;
canvas.height = cH;
context = canvas.getContext( '2d' );
context.drawImage( tmp, 0, 0, cW, cH );
dst.src = canvas.toDataURL( type, quality );
if ( cW <= src.width || cH <= src.height )
return;
tmp.src = dst.src;
}
}
// The images sent as parameters can be in the DOM or be image objects
resize_image( $( '#original' )[0], $( '#smaller' )[0] );
Credits to this post
So something interesting that I found a while ago while working with canvas that might be helpful:
To resize the canvas control on its own, you need to use the height="" and width="" attributes (or canvas.width/canvas.height elements). If you use CSS to resize the canvas, it will actually stretch (i.e.: resize) the content of the canvas to fit the full canvas (rather than simply increasing or decreasing the area of the canvas.
It'd be worth a shot to try drawing the image into a canvas control with the height and width attributes set to the size of the image and then using CSS to resize the canvas to the size you're looking for. Perhaps this would use a different resizing algorithm.
It should also be noted that canvas has different effects in different browsers (and even different versions of different browsers). The algorithms and techniques used in the browsers is likely to change over time (especially with Firefox 4 and Chrome 6 coming out so soon, which will place heavy emphasis on canvas rendering performance).
In addition, you may want to give SVG a shot, too, as it likely uses a different algorithm as well.
Best of luck!
Fast and simple Javascript image resizer:
https://github.com/calvintwr/blitz-hermite-resize
const blitz = Blitz.create()
/* Promise */
blitz({
source: DOM Image/DOM Canvas/jQuery/DataURL/File,
width: 400,
height: 600
}).then(output => {
// handle output
})catch(error => {
// handle error
})
/* Await */
let resized = await blizt({...})
/* Old school callback */
const blitz = Blitz.create('callback')
blitz({...}, function(output) {
// run your callback.
})
History
This is really after many rounds of research, reading and trying.
The resizer algorithm uses #ViliusL's Hermite script (Hermite resizer is really the fastest and gives reasonably good output). Extended with features you need.
Forks 1 worker to do the resizing so that it doesn't freeze your browser when resizing, unlike all other JS resizers out there.
I converted #syockit's answer as well as the step-down approach into a reusable Angular service for anyone who's interested: https://gist.github.com/fisch0920/37bac5e741eaec60e983
I included both solutions because they both have their own pros / cons. The lanczos convolution approach is higher quality at the cost of being slower, whereas the step-wise downscaling approach produces reasonably antialiased results and is significantly faster.
Example usage:
angular.module('demo').controller('ExampleCtrl', function (imageService) {
// EXAMPLE USAGE
// NOTE: it's bad practice to access the DOM inside a controller,
// but this is just to show the example usage.
// resize by lanczos-sinc filter
imageService.resize($('#myimg')[0], 256, 256)
.then(function (resizedImage) {
// do something with resized image
})
// resize by stepping down image size in increments of 2x
imageService.resizeStep($('#myimg')[0], 256, 256)
.then(function (resizedImage) {
// do something with resized image
})
})
Thanks #syockit for an awesome answer. however, I had to reformat a little as follows to make it work. Perhaps due to DOM scanning issues:
$(document).ready(function () {
$('img').on("load", clickA);
function clickA() {
var img = this;
var canvas = document.createElement("canvas");
new thumbnailer(canvas, img, 50, 3);
document.body.appendChild(canvas);
}
function thumbnailer(elem, img, sx, lobes) {
this.canvas = elem;
elem.width = img.width;
elem.height = img.height;
elem.style.display = "none";
this.ctx = elem.getContext("2d");
this.ctx.drawImage(img, 0, 0);
this.img = img;
this.src = this.ctx.getImageData(0, 0, img.width, img.height);
this.dest = {
width: sx,
height: Math.round(img.height * sx / img.width)
};
this.dest.data = new Array(this.dest.width * this.dest.height * 3);
this.lanczos = lanczosCreate(lobes);
this.ratio = img.width / sx;
this.rcp_ratio = 2 / this.ratio;
this.range2 = Math.ceil(this.ratio * lobes / 2);
this.cacheLanc = {};
this.center = {};
this.icenter = {};
setTimeout(process1, 0, this, 0);
}
//returns a function that calculates lanczos weight
function lanczosCreate(lobes) {
return function (x) {
if (x > lobes)
return 0;
x *= Math.PI;
if (Math.abs(x) < 1e-16)
return 1
var xx = x / lobes;
return Math.sin(x) * Math.sin(xx) / x / xx;
}
}
process1 = function (self, u) {
self.center.x = (u + 0.5) * self.ratio;
self.icenter.x = Math.floor(self.center.x);
for (var v = 0; v < self.dest.height; v++) {
self.center.y = (v + 0.5) * self.ratio;
self.icenter.y = Math.floor(self.center.y);
var a, r, g, b;
a = r = g = b = 0;
for (var i = self.icenter.x - self.range2; i <= self.icenter.x + self.range2; i++) {
if (i < 0 || i >= self.src.width)
continue;
var f_x = Math.floor(1000 * Math.abs(i - self.center.x));
if (!self.cacheLanc[f_x])
self.cacheLanc[f_x] = {};
for (var j = self.icenter.y - self.range2; j <= self.icenter.y + self.range2; j++) {
if (j < 0 || j >= self.src.height)
continue;
var f_y = Math.floor(1000 * Math.abs(j - self.center.y));
if (self.cacheLanc[f_x][f_y] == undefined)
self.cacheLanc[f_x][f_y] = self.lanczos(Math.sqrt(Math.pow(f_x * self.rcp_ratio, 2) + Math.pow(f_y * self.rcp_ratio, 2)) / 1000);
weight = self.cacheLanc[f_x][f_y];
if (weight > 0) {
var idx = (j * self.src.width + i) * 4;
a += weight;
r += weight * self.src.data[idx];
g += weight * self.src.data[idx + 1];
b += weight * self.src.data[idx + 2];
}
}
}
var idx = (v * self.dest.width + u) * 3;
self.dest.data[idx] = r / a;
self.dest.data[idx + 1] = g / a;
self.dest.data[idx + 2] = b / a;
}
if (++u < self.dest.width)
setTimeout(process1, 0, self, u);
else
setTimeout(process2, 0, self);
};
process2 = function (self) {
self.canvas.width = self.dest.width;
self.canvas.height = self.dest.height;
self.ctx.drawImage(self.img, 0, 0);
self.src = self.ctx.getImageData(0, 0, self.dest.width, self.dest.height);
var idx, idx2;
for (var i = 0; i < self.dest.width; i++) {
for (var j = 0; j < self.dest.height; j++) {
idx = (j * self.dest.width + i) * 3;
idx2 = (j * self.dest.width + i) * 4;
self.src.data[idx2] = self.dest.data[idx];
self.src.data[idx2 + 1] = self.dest.data[idx + 1];
self.src.data[idx2 + 2] = self.dest.data[idx + 2];
}
}
self.ctx.putImageData(self.src, 0, 0);
self.canvas.style.display = "block";
}
});
I wanted some well defined functions out of answers here so ended up with these which am hoping would be useful for others also,
function getImageFromLink(link) {
return new Promise(function (resolve) {
var image = new Image();
image.onload = function () { resolve(image); };
image.src = link;
});
}
function resizeImageToBlob(image, width, height, mime) {
return new Promise(function (resolve) {
var canvas = document.createElement('canvas');
canvas.width = width;
canvas.height = height;
canvas.getContext('2d').drawImage(image, 0, 0, width, height);
return canvas.toBlob(resolve, mime);
});
}
getImageFromLink(location.href).then(function (image) {
// calculate these based on the original size
var width = image.width / 4;
var height = image.height / 4;
return resizeImageToBlob(image, width, height, 'image/jpeg');
}).then(function (blob) {
// Do something with the result Blob object
document.querySelector('img').src = URL.createObjectURL(blob);
});
Just for the sake of testing this run it on a image opened in a tab.
I just ran a page of side by sides comparisons and unless something has changed recently, I could see no better downsizing (scaling) using canvas vs. simple css. I tested in FF6 Mac OSX 10.7. Still slightly soft vs. the original.
I did however stumble upon something that did make a huge difference and that was using image filters in browsers that support canvas. You can actually manipulate images much like you can in Photoshop with blur, sharpen, saturation, ripple, grayscale, etc.
I then found an awesome jQuery plug-in which makes application of these filters a snap:
http://codecanyon.net/item/jsmanipulate-jquery-image-manipulation-plugin/428234
I simply apply the sharpen filter right after resizing the image which should give you the desired effect. I didn't even have to use a canvas element.
Looking for another great simple solution?
var img=document.createElement('img');
img.src=canvas.toDataURL();
$(img).css("background", backgroundColor);
$(img).width(settings.width);
$(img).height(settings.height);
This solution will use the resize algorith of browser! :)

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