Kurze Scripte und Codeschnipsel ,Bildschirmlupe html

Bildschirmlupe.html

Quell Code

<!DOCTYPE HTML>
    <meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.3.1.min.js"></script>
<style>
  body{
    display: flex;
    flex-direction:column;
    flex-wrap: wrap;
    align-content: center;
    align-items: center;
  }
  h1,p{
    text-align:center;
  }
  #myimage{
    width:600px;
    height:auto;
  }
  #butt{
    width:100px;
    margin-left:calc(50% - 50px);
  }


.img-magnifier-glass {
  position:relative;
  z-index:1;
width: 100px;
height: 100px;
  border-radius:50%;
  border:2px solid blue;

}

  .lupe{
    width:200px;
    height:200px;
  }
</style>

<script>
function magnify(imgID, zoom) {
var img, glass, w, h, bw;
img = document.getElementById(imgID);
glass = document.createElement("DIV");
glass.setAttribute("class", "img-magnifier-glass");
img.parentElement.insertBefore(glass, img);
glass.style.backgroundImage = "url('" + img.src + "')";
glass.style.backgroundRepeat = "no-repeat";
glass.style.backgroundSize = (img.width * zoom) + "px " + (img.height * zoom) + "px";
bw = 3;
w = glass.offsetWidth / 2;
h = glass.offsetHeight / 2;
glass.addEventListener("mousemove", moveMagnifier);
img.addEventListener("mousemove", moveMagnifier);
glass.addEventListener("touchmove", moveMagnifier);
img.addEventListener("touchmove", moveMagnifier);
function moveMagnifier(e) {
var pos, x, y;
e.preventDefault();
pos = getCursorPos(e);
x = pos.x;
y = pos.y;
if (x > img.width - (w / zoom)) {x = img.width - (w / zoom);}
if (x < w / zoom) {x = w / zoom;}
if (y > img.height - (h / zoom)) {y = img.height - (h / zoom);}
if (y < h / zoom) {y = h / zoom;}
glass.style.left = (x - w) -220+ "px";
glass.style.top = (y - h) +120+ "px";
glass.style.backgroundPosition = "-" + ((x * zoom) - w + bw) + "px -" + ((y * zoom) - h + bw) + "px";
}

function getCursorPos(e) {
var a, x = 0, y = 0;
e = e || window.event;
a = img.getBoundingClientRect();
x = e.pageX - a.left;
y = e.pageY - a.top;
x = x - window.pageXOffset;
y = y - window.pageYOffset;
return {x : x, y : y};

}

}

function Testfunktion() {
document.getElementById("myimage").style.visibility = "visible";
magnify("myimage", 3);

}
</script>
</head>
<body>
<div align = "center">
<h1>Image Magnifier Glass</h1>
<p>Mouse over the image:</p>
<input type = "button" value = "KLICK" onclick = "Testfunktion();"/><br><br>
<div class="img-magnifier-container">
<img id="myimage" src="https://www.w3schools.com/howto/img_nature.jpg" width="600" height="400" style = "visibility:hidden"/>
</div>
</div>
</body>
</html>