text: 
  canvas.width = window.innerWidth;
  canvas.height= window.innerHeight;
  
  var c = canvas.getContext("2d");
  
  //set line color / width
  c.lineWidth=3;
  c.strokeStyle= "blue";
  
  c.beginPath();
  c.moveTo(100, 300); //Startpunkt
  c.lineTo(400, 450); //Endpunkt
  c.stroke();