var canvas = {

  width: 100,

  height:36

};

function verification(ctx) {




  // //清空畫布

  ctx.clearRect(0, 0, canvas.width, canvas.height);

  // //生成隨機顏色

  function getRandomColor() {

    return "#" + ("00000" + ((Math.random() * 16777215 + 0.5) >> 0).toString(16)).slice(-6);

  }

  // //定義線性漸變

  var gradient = ctx.createLinearGradient(0, 0, canvas.width, canvas.height);

  gradient.addColorStop("0", getRandomColor());

  gradient.addColorStop("0.5", getRandomColor());

  gradient.addColorStop("1.0", getRandomColor());




  // //生成隨機數(shù)

  function rnd(min, max) {

    return min + Math.floor(Math.random() * (max - min + 1));

  }




  // //繪制干擾線條

  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();

  }




  // //繪制干擾點

  function point() {

    ctx.fillRect(rnd(0, canvas.width), rnd(0, canvas.height), 2, 2);

  }




  // //繪制驗證碼

  var text = rnd(1000, 9999);

  ctx.setFontSize(30)

  ctx.setFillStyle(gradient)

  ctx.fillText(text,2, 25);




  // //生成干擾元素

  for (var i = 0; i < 8; i++) {

    line();

  }

  for (var i = 0; i <100; i++) {

    point();

  }

  ctx.draw()

  return text;

}

module.exports = { verification: verification };