thib8956/test-canvas
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draw animated cross

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Thibaud Gasser 2024-09-23 21:56:01 +02:00
parent e1573b6d36
commit 9dd3b6487a
1 changed files with 36 additions and 12 deletions
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48
main.js
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@ -19,8 +19,7 @@ function drawCircle(ctx) {
let startTime = undefined;
let circles = [];
let crosses = [];
let shapes = [];
let pendingClicks = [];
function animate(ctx, time) {
@ -31,28 +30,31 @@ function animate(ctx, time) {
for (const evt of pendingClicks) {
const h = Math.floor(Math.random() * 255);
if (evt.kind == "circle") {
circles.push({x: evt.x, y: evt.y, t: time, hue: h});
shapes.push({kind: evt.kind, x: evt.x, y: evt.y, t: time, hue: h});
} else if (evt.kind == "cross") {
crosses.push({x: evt.x, y: evt.y, t: time, hue: h});
shapes.push({kind: evt.kind, x: evt.x, y: evt.y, t: time, hue: h});
}
}
pendingClicks = [];
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
for (const circle of circles) {
const dt = time - circle.t;
drawAnimatedCircle(ctx, dt, circle.x, circle.y, circle.hue);
}
for (const cross of crosses) {
drawCross(ctx, cross.hue);
for (const shape of shapes) {
const dt = time - shape.t;
switch (shape.kind) {
case "circle":
drawAnimatedCircle(ctx, dt, shape.x, shape.y, shape.hue);
break;
case "cross":
drawAnimatedCross(ctx, dt, shape.x, shape.y, shape.hue);
break;
}
}
window.requestAnimationFrame(time => animate(ctx, time));
}
function drawAnimatedCircle(ctx, dt, x, y, hue) {
const end = dt*((2*Math.PI) / 1000);
const end = dt*2*Math.PI/500;
ctx.save();
ctx.beginPath();
ctx.arc(x, y, 50, 0, Math.min(end, 2*Math.PI));
@ -63,6 +65,28 @@ function drawAnimatedCircle(ctx, dt, x, y, hue) {
ctx.restore();
}
function drawAnimatedCross(ctx, dt, x, y, hue) {
startPoint = { x: x-50, y: y-50 };
ctx.beginPath();
ctx.moveTo(startPoint.x, startPoint.y);
delta = 100*dt/250;
if (delta < 100) { // draw \
d = Math.min(delta, 100);
ctx.lineTo(startPoint.x + d, startPoint.y + d);
} else { // draw /
ctx.lineTo(startPoint.x + 100, startPoint.y + 100); // keep \ drawn
ctx.moveTo(startPoint.x + 100, startPoint.y);
d = Math.min(delta-100, 100);
ctx.lineTo(startPoint.x +100 - d, startPoint.y + d);
}
ctx.lineWidth = 5;
const percent = Math.trunc(100*Math.min(delta, 100)/100);
ctx.strokeStyle = `hsla(${hue}, ${percent}%, 50%, 1)`;
ctx.stroke();
}
function resizeCanvas(ctx) {
ctx.canvas.width = window.innerWidth;
ctx.canvas.height = window.innerHeight;