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add splines

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Thibaud Gasser 2024-09-27 14:41:24 +02:00
parent a200c3d3cf
commit af199a6d9c
2 changed files with 82 additions and 0 deletions
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spline.html Normal file
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<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body style="margin: 0; padding 0; overflow: hidden; background-color: #000000">
<canvas id="canvas" width="800" height="600"></canvas>
</body>
<script type="module" src="spline.js"></script>
</html>

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spline.js Normal file
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import { resizeCanvas, drawCircle, drawLine, cubicBezier } from "./common.js"
function drawPoints(ctx, points) {
for (const p of points) {
drawCircle(ctx, p, 2, 0xFF00FF);
}
}
function drawCurve(ctx, curve) {
for (let i=0; i < curve.length - 1; ++i) {
drawLine(ctx, curve[i], curve[i+1], 0xFFFFFF);
}
}
function draw(ctx, points) {
const bezier1 = cubicBezier(...points.slice(0, 4));
drawCurve(ctx, bezier1);
const bezier2 = cubicBezier(...points.slice(3, 7));
drawCurve(ctx, bezier2);
drawPoints(ctx, points);
}
function init() {
const canvas = document.getElementById("canvas");
let selection = undefined;
let points = [
{ x: 227, y: 434 },
{ x: 341, y: 234 },
{ x: 649, y: 255 },
{ x: 765, y: 450 },
{ x: 800, y: 500 },
{ x: 850, y: 450 },
{ x: 900, y: 550 },
];
if (canvas.getContext) {
const ctx = canvas.getContext("2d");
resizeCanvas(ctx); // Init canvas
draw(ctx, points);
canvas.onmousedown = (evt) => {
const { clientX, clientY } = evt;
for (const p of points) {
if (Math.abs(p.x - clientX) < 10 && Math.abs(p.y - clientY) < 10) {
selection = points.indexOf(p);
}
}
};
canvas.onmousemove = (evt) => {
if (selection !== undefined) {
points[selection].x = evt.clientX;
points[selection].y = evt.clientY;
// redraw
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
draw(ctx, points);
}
};
canvas.onmouseup = () => {
selection = undefined;
};
}
}
init();