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script.js
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50 lines (39 loc) · 1.06 KB
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const canvas = document.querySelector('#draw');
const ctx = canvas.getContext('2d');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
// ctx.strokeStyle = '#BADA55';
ctx.lineJoin = 'miter';
ctx.lineCap = 'miter';
ctx.lineWidth = '25';
ctx.globalCompositeOperation = 'exclusion';
let isDrawing = false;
let lastX = 0;
let lastY = 0;
let hue = 0;
let direction = true;
function draw(e) {
if (!isDrawing) return;
ctx.strokeStyle = `hsl(${hue}, 100%, 50%)`;
ctx.beginPath();
ctx.moveTo(lastX, lastY);
ctx.lineTo(e.offsetX, e.offsetY);
ctx.stroke();
[lastX, lastY] = [e.offsetX, e.offsetY];
hue++;
if (ctx.lineWidth >= 60 || ctx.lineWidth <= 20) {
direction = !direction;
}
if (direction) {
ctx.lineWidth++;
} else {
ctx.lineWidth--;
}
}
canvas.addEventListener('mousedown', (e) => {
isDrawing = true;
[lastX, lastY] = [e.offsetX, e.offsetY];
});
canvas.addEventListener('mouseup', () => isDrawing = false);
canvas.addEventListener('mouseout', () => isDrawing = false);
canvas.addEventListener('mousemove', draw);