44 lines
908 B
JavaScript
44 lines
908 B
JavaScript
const canvas = document.getElementById("mycanvas");
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const ctx = canvas.getContext("2d");
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/*taille du canvas*/
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function taillecanvas() {
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canvas.width = window.innerWidth;
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canvas.height = window.innerHeight;
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}
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taillecanvas();
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window.addEventListener("resize", taillecanvas);
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/*tracé*/
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ctx.strokeStyle = "black";
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ctx.lineWidth = 0.25;
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/*mémorise la position du x et y précédent*/
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let lastX = null;
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let lastY = null;
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document.addEventListener("mousemove", (e) => {
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if (lastX === null || lastY === null) {
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lastX = e.clientX;
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lastY = e.clientY;
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return;
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}
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ctx.beginPath();
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ctx.moveTo(lastX, lastY);
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ctx.lineTo(e.clientX, e.clientY);
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ctx.stroke();
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lastX = e.clientX;
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lastY = e.clientY;
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});
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const dpr = window.devicePixelRatio || 1;
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canvas.width = window.innerWidth * dpr;
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canvas.height = window.innerHeight * dpr;
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ctx.scale(dpr, dpr);
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