How To Zoom An Image On Mouse Over Using JavaScript

admin_img Posted By Bajarangi soft , Posted On 05-10-2020

In Java script we can zoom image on specified place when mouse over so today we discuss how to zoom image when mouse over on image using java script

How To Zoom An Image On Mouse Over Using JavaScript

Create an Image Zoom
Step 1: Create index.html file and implement below code in it.

<div class="img-zoom-container " style="display: flex">
    <img id="image" src="../image/demo4.jpg" width="300" height="240">
    <div id="result" class="img-zoom-result"></div>
</div>
 

Step 2:Now we create css code to display zoomed image so implement below code in index.html file
The container must have a "relative" positioning.

<style>
    h1 {
        color: red;
    }
    * {box-sizing: border-box;}

    .img-zoom-container {
        position: relative;
    }

    .img-zoom-lens {
        position: absolute;
        border: 1px solid #d4d4d4;
        /*set the size of the lens:*/
        width: 40px;
        height: 40px;
    }

    .img-zoom-result {
        border: 1px solid #d4d4d4;
        /*set the size of the result div:*/
        width: 300px;
        height: 241px;
    }
</style>
 

Step 3:Now we implement javascript to zoom image.

<script>
    function imageZoom(imgID, resultID) {
        var img, lens, result, cx, cy;
        img = document.getElementById(imgID);
        result = document.getElementById(resultID);
        /*create lens:*/
        lens = document.createElement("DIV");
        lens.setAttribute("class", "img-zoom-lens");
        /*insert lens:*/
        img.parentElement.insertBefore(lens, img);
        /*calculate the ratio between result DIV and lens:*/
        cx = result.offsetWidth / lens.offsetWidth;
        cy = result.offsetHeight / lens.offsetHeight;
        /*set background properties for the result DIV:*/
        result.style.backgroundImage = "url('" + img.src + "')";
        result.style.backgroundSize = (img.width * cx) + "px " + (img.height * cy) + "px";
        /*execute a function when someone moves the cursor over the image, or the lens:*/
        lens.addEventListener("mousemove", moveLens);
        img.addEventListener("mousemove", moveLens);
        /*and also for touch screens:*/
        lens.addEventListener("touchmove", moveLens);
        img.addEventListener("touchmove", moveLens);
        function moveLens(e) {
            var pos, x, y;
            /*prevent any other actions that may occur when moving over the image:*/
            e.preventDefault();
            /*get the cursor's x and y positions:*/
            pos = getCursorPos(e);
            /*calculate the position of the lens:*/
            x = pos.x - (lens.offsetWidth / 2);
            y = pos.y - (lens.offsetHeight / 2);
            /*prevent the lens from being positioned outside the image:*/
            if (x > img.width - lens.offsetWidth) {x = img.width - lens.offsetWidth;}
            if (x < 0) {x = 0;}
            if (y > img.height - lens.offsetHeight) {y = img.height - lens.offsetHeight;}
            if (y < 0) {y = 0;}
            /*set the position of the lens:*/
            lens.style.left = x + "px";
            lens.style.top = y + "px";
            /*display what the lens "sees":*/
            result.style.backgroundPosition = "-" + (x * cx) + "px -" + (y * cy) + "px";
        }
        function getCursorPos(e) {
            var a, x = 0, y = 0;
            e = e || window.event;
            /*get the x and y positions of the image:*/
            a = img.getBoundingClientRect();
            /*calculate the cursor's x and y coordinates, relative to the image:*/
            x = e.pageX - a.left;
            y = e.pageY - a.top;
            /*consider any page scrolling:*/
            x = x - window.pageXOffset;
            y = y - window.pageYOffset;
            return {x : x, y : y};
        }
    }
</script>

Step 4:Now Implement java script to Initiate the zoom Function.
<script>
    // Initiate zoom effect:
    imageZoom("image", "result");
</script>


Complete code for zooming image on mouse over using java script.
<!DOCTYPE html>
<html>
<head>
    <title>How To Zoom An Image On Mouse Over Using JavaScript</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
</head>
<style>
    h1 {
        color: red;
    }

    * {
        box-sizing: border-box;
    }

    .img-zoom-container {
        position: relative;
    }

    .img-zoom-lens {
        position: absolute;
        border: 1px solid #d4d4d4;
        /*set the size of the lens:*/
        width: 40px;
        height: 40px;
    }

    .img-zoom-result {
        border: 1px solid #d4d4d4;
        /*set the size of the result div:*/
        width: 300px;
        height: 241px;
    }
</style>
<script>
    function imageZoom(imgID, resultID) {
        var img, lens, result, cx, cy;
        img = document.getElementById(imgID);
        result = document.getElementById(resultID);
        /*create lens:*/
        lens = document.createElement("DIV");
        lens.setAttribute("class", "img-zoom-lens");
        /*insert lens:*/
        img.parentElement.insertBefore(lens, img);
        /*calculate the ratio between result DIV and lens:*/
        cx = result.offsetWidth / lens.offsetWidth;
        cy = result.offsetHeight / lens.offsetHeight;
        /*set background properties for the result DIV:*/
        result.style.backgroundImage = "url('" + img.src + "')";
        result.style.backgroundSize = (img.width * cx) + "px " + (img.height * cy) + "px";
        /*execute a function when someone moves the cursor over the image, or the lens:*/
        lens.addEventListener("mousemove", moveLens);
        img.addEventListener("mousemove", moveLens);
        /*and also for touch screens:*/
        lens.addEventListener("touchmove", moveLens);
        img.addEventListener("touchmove", moveLens);

        function moveLens(e) {
            var pos, x, y;
            /*prevent any other actions that may occur when moving over the image:*/
            e.preventDefault();
            /*get the cursor's x and y positions:*/
            pos = getCursorPos(e);
            /*calculate the position of the lens:*/
            x = pos.x - (lens.offsetWidth / 2);
            y = pos.y - (lens.offsetHeight / 2);
            /*prevent the lens from being positioned outside the image:*/
            if (x > img.width - lens.offsetWidth) {
                x = img.width - lens.offsetWidth;
            }
            if (x < 0) {
                x = 0;
            }
            if (y > img.height - lens.offsetHeight) {
                y = img.height - lens.offsetHeight;
            }
            if (y < 0) {
                y = 0;
            }
            /*set the position of the lens:*/
            lens.style.left = x + "px";
            lens.style.top = y + "px";
            /*display what the lens "sees":*/
            result.style.backgroundPosition = "-" + (x * cx) + "px -" + (y * cy) + "px";
        }

        function getCursorPos(e) {
            var a, x = 0, y = 0;
            e = e || window.event;
            /*get the x and y positions of the image:*/
            a = img.getBoundingClientRect();
            /*calculate the cursor's x and y coordinates, relative to the image:*/
            x = e.pageX - a.left;
            y = e.pageY - a.top;
            /*consider any page scrolling:*/
            x = x - window.pageXOffset;
            y = y - window.pageYOffset;
            return {x: x, y: y};
        }
    }
</script>
<body>
<div class="container">
    <br>
    <br>
    <div class="text-center">
        <h1>How To Zoom An Image On Mouse Over Using JavaScript</h1>
    </div>
    <br>
    <div class="well">
        <h1>Image Zoom</h1>

        <p>Mouse over the image:</p>

        <div class="img-zoom-container " style="display: flex">
            <img id="image" src="../image/demo4.jpg" width="300" height="240">
            <div id="result" class="img-zoom-result"></div>
        </div>

        <p>The image must be placed inside a container with relative positioning.</p>
        <p>The result can be put anywhere on the page, but must have the class name "img-zoom-result".</p>
        <p>Make sure both the image and the result have IDs. These IDs are used when a javaScript initiates the zoom
            effect.</p>

        <script>
            // Initiate zoom effect:
            imageZoom("image", "result");
        </script>
    </div>
    <div>
</body>
</html>





 

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