Question

I would like to know if there are any javascript libraries to help in rendering graphics. I searched google and didn’t find any tools. I want to make Gauss curves in canvas.

Answer 1

This took me 15 seconds to find. Play with it until it gets you what you like.

$(document).ready(drawGaussian);

var canvasContext;
var points;
var noise = 0;

function drawGaussian()
{   
canvasContext = document.getElementById("gaussian-canvas").getContext("2d");

document.getElementById("gaussian-canvas").onclick = cycleNoise;

cycleNoise();
}

function cycleNoise()
{   
canvasContext.clearRect(0, 0, 400, 400);

var m = Math.random() > .4
var amount = Math.round(Math.random() * 20000);
var size = Math.round(Math.random() * 3)+1;

document.getElementById("particles").innerHTML = amount;
document.getElementById("size").innerHTML = size;

switch(noise)
{
    case 0:
        drawGaussianField(amount, size, 200, 200, 400, 100, m);
        document.getElementById("type").innerHTML = (m ? "Monochromatic" : "Chromatic") + " Field";
        break;
    case 1:
        drawGaussianCurves(amount, size, 200, 200, 400, 150, m);
        document.getElementById("type").innerHTML = (m ? "Monochromatic" : "Chromatic") + " Curves";
        break;
    case 2:
        drawGaussianDiamond(amount, size, 200, 200, 400, 130, m);
        document.getElementById("type").innerHTML = (m ? "Monochromatic" : "Chromatic") + " Diamond";
        break;
    case 3:
        drawGaussianOval(amount, size, 200, 200, 300, 300, m);
        document.getElementById("type").innerHTML = (m ? "Monochromatic" : "Chromatic") + " Circle";
        break;
    case 4:
        drawGaussianBurst(amount, size, 200, 200, 120, 120, m);
        document.getElementById("type").innerHTML = (m ? "Monochromatic" : "Chromatic") + " Burst";
        break;
}

noise++;

if(noise > 4) noise = 0;
}


function drawGaussianField(amount, thickness, x, y, width, height, monochromatic)
{
for(i = 0; i < amount; i++)
{
    points = getGaussianPoints();

    setColor(monochromatic);
    canvasContext.fillRect(x + ((width*.5) * points[3]), y + ((height*.5) * points[2]), thickness, thickness);  
}
}

function drawGaussianCurves(amount, thickness, x, y, width, height, monochromatic){
for(i = 0; i < amount; i++)
{
    points = getGaussianPoints();

    setColor(monochromatic);
    canvasContext.fillRect(x + ((width*.5) * points[0]), y + ((height*.5) * points[2]), thickness, thickness);  
}
}

function drawGaussianDiamond(amount, thickness, x, y, width, height, monochromatic){
for(i = 0; i < amount; i++)
{
    points = getGaussianPoints();

    setColor(monochromatic);
    canvasContext.fillRect(x + ((width*.5) * points[0]), y + ((height*.5) * points[3]), thickness, thickness);  
}
}

function drawGaussianOval(amount, thickness, x, y, width, height, monochromatic){
for(i = 0; i < amount; i++)
{
    points = getGaussianPoints();

    setColor(monochromatic);
    canvasContext.fillRect(x + ((width*.5) * points[0]), y + ((height*.5) * points[1]), thickness, thickness);  
}
}

function drawGaussianBurst(amount, thickness, x, y, width, height, monochromatic){
for(i = 0; i < amount; i++)
{
    points = getGaussianPoints();

    setColor(monochromatic);
    canvasContext.fillRect(x + ((width*.5) * points[2]), y + ((height*.5) * points[3]), thickness, thickness);  
}
}

function setColor(val){
if(val)
{
    canvasContext.fillStyle = '#ffffff';
}
else
{
    canvasContext.fillStyle = "#"+Math.floor(Math.random()*16777215).toString(16);
}
}

function getGaussianPoints(){
var x1, x2, w, y1, y2;

do {
    x1 = 2.0 * Math.random() - 1.0;
    x2 = 2.0 * Math.random() - 1.0;
    w = x1 * x1 + x2 * x2;
} while ( w >= 1.0 );

w = Math.sqrt( (-2.0 * Math.log( w ) ) / w );
y1 = x1 * w;
y2 = x2 * w;

return [x1, x2, y1, y2];
}