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Bezier Curves in Javascript
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<!DOCTYPE html> | |
<html> | |
<head> | |
</head> | |
<body> | |
<canvas id="myCanvas" width="800" height="400" style="border:1px solid #000000;"> | |
Your browser does not support the HTML canvas tag. | |
</canvas> | |
<input type="range" min="1" max="100" value="1" class="slider" id="tval"> | |
<script> | |
function draw() { | |
var tval = document.getElementById("tval"); | |
var canvas = document.getElementById("myCanvas"); | |
var ctx = canvas.getContext("2d"); | |
var p1 = {x: 70, y: 200}; | |
var p2 = {x: 200, y: 50}; | |
var p3 = {x: 200, y: 300}; | |
function addPoint(p1, p2) { | |
return {x: p1.x+p2.x, y: p1.y+p2.y}; | |
} | |
function subPoint(p1, p2) { | |
return {x: p1.x-p2.x, y: p1.y-p2.y}; | |
} | |
function lerp(p1, p2, t) { | |
// t = time or percentage how far between p1 and p2 | |
var lx = (1 - t) * p1.x + t * p2.x; | |
var ly = (1 - t) * p1.y + t * p2.y; | |
return {x: lx, y: ly}; | |
} | |
ctx.fillStyle = "black"; | |
ctx.fillRect(0, 0, canvas.width, canvas.height); | |
ctx.beginPath(); | |
ctx.moveTo(p1.x, p1.y); | |
ctx.lineTo(p2.x, p2.y); | |
ctx.lineTo(p3.x, p3.y); | |
ctx.strokeStyle = "red"; | |
ctx.stroke(); | |
tval.addEventListener("change", function() { | |
var t = tval.value / 100; | |
var l1 = lerp(p1, p2, t); | |
var l2 = lerp(p2, p3, t); | |
var q1 = lerp(l1, l2, t); | |
ctx.fillStyle = "red"; | |
ctx.fillRect(q1.x, q1.y, 10, 10); | |
console.log(q1); | |
}, false); | |
} | |
window.requestAnimationFrame(draw); | |
</script> | |
</body> | |
</html> | |
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