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41 lines
1.4 KiB
41 lines
1.4 KiB
canvas(id="snow") 不支持canvas
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style
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| canvas#snow { position: absolute; z-index: -1; top: 0; left: 0; opacity: 0.5; }
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script(type="text/javascript", src="https://code.jquery.com/jquery-3.6.0.min.js")
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script
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| $(function () {
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| var W = $(window).width(),
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| H = $(window).height(),
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| x2 = -15, len = 30, count = 100;
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| var canvas = document.getElementById("snow");
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| canvas.width = W;
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| canvas.height = H;
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| var ctx = canvas.getContext('2d');
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| setInterval(clearCanvas,100);
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| function clearCanvas() {
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| ctx.clearRect(0, 0, W, H);
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| draws();
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| }
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| function draw(x, y) {
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| //canvas写渐变：createLinearGradient（startX,startY,endX,endY）
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| var grd = ctx.createLinearGradient(x, y, x + x2, y + len);
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| grd.addColorStop(0, "rgba(0,0,0,0)");
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| grd.addColorStop(0.5, "rgba(105,105,105,1)");
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| grd.addColorStop(1, "rgba(255,255,255,1)");
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| ctx.strokeStyle = grd;
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| ctx.beginPath();
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| ctx.moveTo(x, y);
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| ctx.lineTo(x + x2, y + len);
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| ctx.lineWidth = 2;
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| ctx.stroke();
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| ctx.closePath();
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| }
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| function draws() {
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| for (var i = 1; i <= count; i++) {
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| draw(Math.random() * W, Math.random() * H);
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| }
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| }
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|});
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