WeChat applet QR code canvas drawing
var canvas = { width: 100, height:36 }; function verification(ctx) { // //清空画布 ctx.clearRect(0, 0, canvas.width, canvas.height); // //生成随机颜色 function getRandomColor() { return "#" + ("00000" + ((Math.random() * 16777215 + 0.5) >> 0).toString(16)).slice(-6); } // //定义线性渐变 var gradient = ctx.createLinearGradient(0, 0, canvas.width, canvas.height); gradient.addColorStop("0", getRandomColor()); gradient.addColorStop("0.5", getRandomColor()); gradient.addColorStop("1.0", getRandomColor()); // //生成随机数 function rnd(min, max) { return min + Math.floor(Math.random() * (max - min + 1)); } // //绘制干扰线条 function line() { ctx.beginPath(); ctx.moveTo(rnd(0, canvas.width), rnd(0, canvas.height)); ctx.lineTo(rnd(0, canvas.width), rnd(0, canvas.height)); ctx.closePath(); ctx.lineWidth = rnd(1, 3); ctx.setFillStyle(gradient) ctx.stroke(); } // //绘制干扰点 function point() { ctx.fillRect(rnd(0, canvas.width), rnd(0, canvas.height), 2, 2); } // //绘制验证码 var text = rnd(1000, 9999); ctx.setFontSize(30) ctx.setFillStyle(gradient) ctx.fillText(text,2, 25); // //生成干扰元素 for (var i = 0; i < 8; i++) { line(); } for (var i = 0; i <100; i++) { point(); } ctx.draw() return text; } module.exports = { verification: verification };
Just put the above directly in a js and expose the method. , By the way, about the style issue, because there is no need to write another article, style: padding,
In the past, I was sometimes used to padding: 0px on html pages, which was set to 0, but in small In the program, if you write padding: 0rpx, there will still be padding. If you write padding: 0, just don’t include units.
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