Develop Reference

Circle is not connecting through lines properly using Canvas

I am trying to create 11 circles which connected through lines with a middle circle. I am trying to draw the circles. Here I have doing some r&d but I could not able to make lines. Please help me to complete this.
var canvas, ctx;
var circlePoints = [];
function createCanvasPainting() {
canvas = document.getElementById('myCanvas');
if (!canvas || !canvas.getContext) {
return false;
}
canvas.width = 600;
canvas.height = 600;
ctx = canvas.getContext('2d');
ctx.strokeStyle = '#B8D9FE';
ctx.fillStyle = '#B8D9FE';
ctx.translate(300, 250);
ctx.arc(0, 0, 50, 0, Math.PI * 2); //center circle
ctx.stroke();
ctx.fill();
var angleRotate = 0;
for (var i=0; i<11; i++) {
if (i > 0) {
angleRotate += 32.72;
}
lineToAngle(ctx, 0, 0, 200, angleRotate);
}
}
function lineToAngle(ctx, x1, y1, length, angle) {
angle *= Math.PI / 180;
var x2 = x1 + length * Math.cos(angle),
y2 = y1 + length * Math.sin(angle);
ctx.beginPath();
ctx.moveTo(x1, y1);
ctx.lineTo(x2, y2);
ctx.lineWidth = 1;
ctx.arc(x2, y2, 40, 0, Math.PI * 2);
ctx.fill();
ctx.stroke();
circlePoints.push({x: x2, y: y2});
// console.log(circlePoints);
}
createCanvasPainting();
<canvas id="myCanvas"></canvas>
Here is my JSFiddle Link

See below I removed all the "noise" from your code.
Just circles with lines connecting with a middle circle.
canvas = document.getElementById('myCanvas');
canvas.width = canvas.height = 200;
ctx = canvas.getContext('2d');
ctx.lineWidth = 1;
ctx.translate(99, 99);
angle = 0;
function draw() {
ctx.clearRect(-99, -99, 200, 200);
ctx.beginPath();
ctx.arc(0, 0, 35 + Math.cos(angle / 3000), 0, Math.PI * 2);
ctx.stroke();
ctx.fill();
for (var i = 0; i < 11; i++) {
a = angle * Math.PI / 180;
x = 80 * Math.cos(a)
y = 80 * Math.sin(a)
ctx.beginPath();
ctx.arc(x, y, 18, 0, Math.PI * 2);
ctx.moveTo(x, y);
ctx.lineTo(0, 0);
ctx.fill();
ctx.stroke();
angle += 32.7;
}
}
setInterval(draw, 10);
<canvas id="myCanvas"></canvas>

How to get coordinates of every circle from this Canvas

I need to create a pattern where 5 circles connected by lines to a middle main circle.
So I have created dynamically by rotating in some certain angle. Now I need each and every circle's x and y axis coordinates for capturing the click events on every circle.
Please help me how to find out of coordinates of every circle?
var canvas, ctx;
function createCanvasPainting() {
canvas = document.getElementById('myCanvas');
if (!canvas || !canvas.getContext) {
return false;
}
canvas.width = 600;
canvas.height = 600;
ctx = canvas.getContext('2d');
ctx.strokeStyle = '#B8D9FE';
ctx.fillStyle = '#B8D9FE';
ctx.translate(300, 250);
ctx.arc(0, 0, 50, 0, Math.PI * 2); //center circle
ctx.stroke();
ctx.fill();
drawChildCircles(5);
fillTextMultiLine('Test Data', 0, 0);
drawTextInsideCircles(5);
}
function drawTextInsideCircles(n) {
let ang_unit = Math.PI * 2 / n;
ctx.save();
for (var i = 0; i < n; i++) {
ctx.rotate(ang_unit);
//ctx.moveTo(0,0);
fillTextMultiLine('Test Data', 200, 0);
ctx.strokeStyle = '#B8D9FE';
ctx.fillStyle = '#B8D9FE';
}
ctx.restore();
}
function drawChildCircles(n) {
let ang_unit = Math.PI * 2 / n;
ctx.save();
for (var i = 0; i < n; ++i) {
ctx.rotate(ang_unit);
ctx.beginPath();
ctx.moveTo(0,0);
ctx.lineTo(100,0);
ctx.arc(200, 0, 40, 0, Math.PI * 2);
let newW = ctx.fill();
ctx.stroke();
}
ctx.restore();
}
function fillTextMultiLine(text, x, y) {
ctx.font = 'bold 13pt Calibri';
ctx.textAlign = 'center';
ctx.fillStyle = "#FFFFFF";
// Defining the `textBaseline`…
ctx.textBaseline = "middle";
var lineHeight = ctx.measureText("M").width * 1.2;
var lines = text.split("\n");
for (var i = 0; i < lines.length; ++i) {
// console.log(lines);
if (lines.length > 1) {
if (i == 0) {
y -= lineHeight;
} else {
y += lineHeight;
}
}
ctx.fillText(lines[i], x, y);
}
}
createCanvasPainting();
<canvas id="myCanvas"></canvas>

The problem here is that you are rotating the canvas matrix and your circles are not aware of their absolute positions.
Why don't you use some simple trigonometry to determine the center of your circle and the ending of the connecting lines ?
function lineToAngle(ctx, x1, y1, length, angle) {
angle *= Math.PI / 180;
var x2 = x1 + length * Math.cos(angle),
y2 = y1 + length * Math.sin(angle);
ctx.moveTo(x1, y1);
ctx.lineTo(x2, y2);
ctx.stroke();
return {x: x2, y: y2};
}
Ref: Finding coordinates after canvas Rotation
After that, given the xy center of your circles, calculating if a coord is inside a circle, you can apply the following formula:
Math.sqrt((x1-x0)*(x1-x0) + (y1-y0)*(y1-y0)) < r
Ref: Detect if user clicks inside a circle

removing the js script from html page

<!DOCTYPE html5>
<html>
<head>
<title>disturbed</title>
<script>
window.onload = function() {
// create the canvas
var canvas = document.createElement("canvas"),
c = canvas.getContext("2d");
var particles = {};
var particleIndex = 0;
var particleNum = 15;
// set canvas size
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
// add canvas to body
document.body.appendChild(canvas);
// style the canvas
c.fillStyle = "black";
c.fillRect(0, 0, canvas.width, canvas.height);
function Particle() {
this.x = canvas.width / 2;
this.y = canvas.height / 2;
this.vx = Math.random() * 10 - 5;
this.vy = Math.random() * 10 - 5;
this.gravity = 0.3;
particleIndex++;
particles[particleIndex] = this;
this.id = particleIndex;
this.life = 0;
this.maxLife = Math.random() * 30 + 60;
this.color = "hsla(" + parseInt(Math.random() * 360, 10) + ",90%,60%,0.5";
}
Particle.prototype.draw = function() {
this.x += this.vx;
this.y += this.vy;
if (Math.random() < 0.1) {
this.vx = Math.random() * 10 - 5;
this.vy = Math.random() * 10 - 5;
}
this.life++;
if (this.life >= this.maxLife) {
delete particles[this.id];
}
c.fillStyle = this.color;
//c.fillRect(this.x, this.y, 5, 10);
c.beginPath();
c.arc(this.x, this.y, 2.5, 0, 2 * Math.PI);
c.fill();
};
setInterval(function() {
//normal setting before drawing over canvas w/ black background
c.globalCompositeOperation = "source-over";
c.fillStyle = "rgba(0,0,0,0.5)";
c.fillRect(0, 0, canvas.width, canvas.height);
for (var i = 0; i < particleNum; i++) {
new Particle();
}
// c.globalCompositeOperation = "darken";
for (var i in particles) {
particles[i].draw();
}
}, 30);
};
</script>
</head>
<body>
</body>
</html>
The code below is all correct but its just two densed i want to make it easier and not to populated . what i want to do is make the script that i have into a separate file like "anything.js" so that i can load it into my html main file by just calling out the main functions like particle() in ,window.onload = function() which will be on the main page .
The reason is because i want to add this script to many html pages and i dont want to copy all of the lengthy script in to my code again and again .
Please answer this , it would be really helful.

HTML :
<!DOCTYPE html5>
<html>
<head>
<title>disturbed</title>
</head>
<body>
<script src="toto.js" type="text/javascript"></script>
<script type="text/javascript">
window.onload = function() {
Particle();
};
</script>
</body>
</html>
toto.js :
//create the canvas
var canvas = document.createElement("canvas"),
c = canvas.getContext("2d");
var particles = {};
var particleIndex = 0;
var particleNum = 15;
// set canvas size
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
// add canvas to body
document.body.appendChild(canvas);
// style the canvas
c.fillStyle = "black";
c.fillRect(0, 0, canvas.width, canvas.height);
function Particle() {
this.x = canvas.width / 2;
this.y = canvas.height / 2;
this.vx = Math.random() * 10 - 5;
this.vy = Math.random() * 10 - 5;
this.gravity = 0.3;
particleIndex++;
particles[particleIndex] = this;
this.id = particleIndex;
this.life = 0;
this.maxLife = Math.random() * 30 + 60;
this.color = "hsla(" + parseInt(Math.random() * 360, 10) + ",90%,60%,0.5";
}
Particle.prototype.draw = function() {
this.x += this.vx;
this.y += this.vy;
if (Math.random() < 0.1) {
this.vx = Math.random() * 10 - 5;
this.vy = Math.random() * 10 - 5;
}
this.life++;
if (this.life >= this.maxLife) {
delete particles[this.id];
}
c.fillStyle = this.color;
//c.fillRect(this.x, this.y, 5, 10);
c.beginPath();
c.arc(this.x, this.y, 2.5, 0, 2 * Math.PI);
c.fill();
};
setInterval(function() {
//normal setting before drawing over canvas w/ black background
c.globalCompositeOperation = "source-over";
c.fillStyle = "rgba(0,0,0,0.5)";
c.fillRect(0, 0, canvas.width, canvas.height);
for (var i = 0; i < particleNum; i++) {
new Particle();
}
// c.globalCompositeOperation = "darken";
for (var i in particles) {
particles[i].draw();
}
}, 30);

I see you have a scope issue.
Variables are passed from script to script. However, in your case, you declare Particle inside window.onload so it only gets defined inside it and you can't use it elsewhere.
The right way to export your script into a separate file would be to declare Particle in the scope of the whole script, as in:
// anything.js
function Particle() {
...
}
Note that you'd need a bit of rewriting, since I can see that you use variables like canvas (which are only defined in the scope of window.onload) inside Particle's code.

Constructor, loops and arrays practice in vanilla JS

I'm trying to make an animation where particles flow from one side the other like a flock of birds. You can see a live version on my semi-finished portfolio here: https://benjamingibbsportfolio.000webhostapp.com/
I'm in the process of learning constructor functions, so I've decided to redo the above project using that type of programming.
I've managed to basically complete it, apart from the fact it only displays one particle/flake - it should show 100?
for(var i = 0; i < 100; i++)
{
flakes[i] = new Flake();
}
Where have I gone wrong?
Are all the particles simply being drawn at the same place?
I've uploaded the code here: https://jsfiddle.net/q7ja8qxv/

A single flake is drawn with this function:
this.display = function() {
ctx.clearRect(0, 0, w, h);
ctx.fillStyle = "#ffff00";
ctx.beginPath();
ctx.moveTo(this.x, this.y);
ctx.arc(this.x, this.y, this.r, 0, Math.PI * 2, true);
ctx.fill();
}
The source of the problem is the first line of the function:
ctx.clearRect(0, 0, w, h);
This clears the whole canvas...
This means that every flake "erases" the previous flake(s).
As a fix you have to remove the ctx.clearRect() call from Flake.display() and instead call it in a place where it is only executed once, before you start drawing the flakes. For example in drawFlakes() right before the loop:
function drawFlakes() {
ctx.clearRect(0, 0, w, h);
for (i = 0; i < flakes.length; i++) {
flakes[i].display();
flakes[i].move();
flakes[i].update();
}
angle += 0.01;
}
Complete example:
var canvas = document.getElementById('stars');
var ctx = canvas.getContext('2d')
var w = window.innerWidth;
var h = window.innerHeight;
var flakes = [];
var angle = 0;
canvas.width = w;
canvas.height = h;
for (var i = 0; i < 20; i++) {
flakes[i] = new Flake();
}
function drawFlakes() {
ctx.clearRect(0, 0, w, h);
for (i = 0; i < flakes.length; i++) {
flakes[i].display();
flakes[i].move();
flakes[i].update();
}
angle += 0.01;
}
function Flake() {
this.x = Math.random() * w;
this.y = Math.random() * h;
this.r = Math.random() * 5 + 2;
this.d = Math.random() * 1;
this.display = function() {
ctx.fillStyle = "#ffff00";
ctx.beginPath();
ctx.moveTo(this.x, this.y);
ctx.arc(this.x, this.y, this.r, 0, Math.PI * 2, true);
ctx.fill();
}
this.move = function() {
this.y += Math.pow(this.d, 2) + 1;
this.x += Math.sin(angle) * 60;
};
this.update = function() {
if (this.y > h) {
this.x = Math.random() * w;
this.y = 0;
this.r = this.r;
this.d = this.d;
}
};
}
setInterval(drawFlakes, 25);
body {
background: black;
overflow: hidden;
}
<canvas id="stars"></canvas>

Drawing Object Arrays with JS Canvas

I'm new to JS, and I have not gone into jQuery or such yet. All that I'm trying to do is draw 4 simple circles on the canvas. I put the objects into an array because I planned to possibly expand in the future, but that information is irrelevant.
What I need help with, is understanding the basics of how to create objects within an array and then display them on a canvas. Here is my dysfunctionate code:
var canvas = document.getElementById("canvas"),
ctx = canvas.getContext("2d");
var W = 400, H = 500
canvas.width = W, canvas.height = H;
var ball = [3];
for (i===0;i<=3; i++){
ball[i] = {
x: (Math.floor(Math.random() * 350) + 50),
y: (Math.floor(Math.random() * 450) + 50),
color: "red",
radius: (Math.floor(Math.random() * 35) + 15),
draw: balls(x, y, color, radius)
};
}
function balls(x, y, color, radius){
ctx.beginPath();
ctx.arc(x, y, radius, 0, 2*Math.PI, false);
ctx.fillStyle = color;
ctx.fill();
ctx.closePath();
}

You are making it very complex use this method:
function ball(){
this.x = Math.random() * 100;
this.y = Math.random() * 100;
this.radius = Math.random() * 10;
this.color = "#" + (Math.random() * 16777215).toString(16);
this.draw = function(){
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, 2*Math.PI, false);
ctx.fillStyle = color;
ctx.fill();
ctx.closePath();
}
}
var balls = [];
for(var i = 0; i < 4; i++) {
balls[i] = new ball();
balls[i].draw();
}

You can simply assign draw to the balls function like so:
ball[i] = {
....
draw: balls
};
Then to draw it, once you defined ball[i] call it's draw() function:
var b = ball[i];
b.draw(b.x, b.y, b.color ,b.radius);
Example Here
Edit: Using no parentheses like ball, is how to reference the function ball() itself. And one last thing, you need to change for (i===0;i<=3; i++) to for (i=0;i<=3; i++). The === is a strict comparison operator, = is assignment.