A simple example of scaling and dragging a jquery image

2020-03-30 01:14:44
OfStack

1. Simple scaling without using jquery:


<HTML> 
<HEAD> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> 
<TITLE>onMouseWheel</TITLE> 
<SCRIPT> 
var count = 10; 
function Picture() 
{ 
count = Counting(count); 
Resize(count); 
return false; 
} 
function Counting(count){ 
if (event.wheelDelta >= 120) 
count++; 
else if (event.wheelDelta <= -120) 
count--; 
return count; 
} 
function Resize(count){ 
oImage.style.zoom = count + '0%'; 
oCounter.innerText = count + '0%'; 
} 
</SCRIPT> 
</HEAD> 
<BODY> 
<div align=center> 
<span style="font-weight:bold">Size = 
<span id="oCounter" style="color:red;">100%</span></span> 
<img id="oImage" src="images/aaa.gif" onmousewheel="return Picture();" > 
</div> 
</BODY> 
</HTML>

1. Using jquery to achieve scaling and dragging:


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <title></title>
    <style type="text/css">
        #imgBox
        {
            width: 200px;
            height: 200px;
            background: red;
            overflow: hidden;
            margin: auto;
            position: relative;
        }
        #imgMain
        {
            position: relative;
            top: -200px;
        }
    </style>
    <script src="js/jquery-1.2.6.js" type="text/javascript"></script>
    <script type="text/javascript" language="javascript">
        $(function () {
            var event;
            if ($.browser.mozilla) {
                event = "DOMMouseScroll";
            }
            else {
                event = "mousewheel";
            }
            $("#divBlock").bind(event,
        function (e) {
            var evt = window.event || e;
            var newWidth;
            var newHeight;
            var newLeft;
            var newTop;
            var overHeight = $("#divBlock").height();
            if (evt.detail > 0 || evt.wheelDelta < 0) {
                newWidth = $("#imgMain").width() - 20;
                newHeight = $("#imgMain").height() - 20;
                newLeft = $("#imgMain").position().left + 10;
                newTop = $("#imgMain").position().top + 10 - overHeight;
            }
            else {
                newWidth = $("#imgMain").width() + 20;
                newHeight = $("#imgMain").height() + 20;
                newLeft = $("#imgMain").position().left - 10;
                newTop = $("#imgMain").position().top - 10 - overHeight;
            }
            $("#imgMain").css({ left: newLeft + "px", top: newTop + "px" });
            $("#imgMain").width(newWidth);
            $("#imgMain").height(newHeight);
        }
        );
            $("#divBlock").bind("mousedown", function (e) {
                var xo = e.pageX;
                var yo = e.pageY;
                var imgLeft = $("#imgMain").position().left;
                var imgTop = $("#imgMain").position().top;
                var overHeight = $("#divBlock").height();
                $("#divBlock").bind("mousemove", function (e) {
                    window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();
                    var x = e.pageX;
                    var y = e.pageY;
                    var bX = $("#imgBox").offset().left;
                    var bY = $("#imgBox").offset().top;
                    $("#imgMain").css("left", x - bX - (xo - bX) + imgLeft);
                    $("#imgMain").css("top", y - bY - (yo - bY) - overHeight + imgTop);
                });
            });
            $("#divBlock").bind("mouseup mouseout", function () {
                $("#divBlock").unbind("mousemove");
            });
        });
    </script>
</head>
<body>
    <div id="imgBox">
        <div style="width: 200px; height: 200px; cursor: pointer; position: relative; left: 0;
            top: 0; filter: alpha(opacity=0); opacity: 0; -moz-opacity: 0; background: blue;
            z-index: 999;" id="divBlock">
        </div>
        <img src="test.jpg" width="200" height="200" alt="" id="imgMain" />
    </div>
</body>
</html>