createCanvas(400, 400);

}

​

function draw() {

  background(0);

  strokeWeight(30);

  gradientLine(50, 50, mouseX, mouseY,'#ffffffff', '#ffffff00');

}

​

function gradientLine(x1, y1, x2, y2, color1, color2) {

  // linear gradient from start to end of line

  var grad = this.drawingContext.createLinearGradient(x1, y1, x2, y2);

  grad.addColorStop(0, color1);

  grad.addColorStop(1, color2);

​

  this.drawingContext.strokeStyle = grad;

​

  line(x1, y1, x2, y2);

}