Cross-browser Supported Image Skew effect using Javascript

Image shaking effect with javascript. Today’s lesson quite entertaining, we’ll learn how to construct a shaking effect. For clarity, we will apply this effect to the picture. You will need to hold down by mouse a certain area in the image and move it to another location (drag). Now, I sure that better to see our online demonstration. How did it achieve? In principle, simply enough, the entire ‘image’ divided into 4 sectors. Place, where we will begin to drag by mouse – is the boundary separating of our four pictures. And shaking effect itself – will only change the sizes of our sectors and pictures in them. Read more.

Here are samples and downloadable package:

Contents

Step 1. HTML
index.html
Step 2. CSS
css/main.css
Step 3. JS
js/main.js
Step 4. Images
Conclusion

Live Demo

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download in package

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Ok, download the example files and lets start coding !

Step 1. HTML

As usual, we start with the HTML. This is source code of our sample:

index.html

<html> 
  
<head> 
  
    <title>Image shaking effect using pure JavaScript</title> 
  
    <link rel="stylesheet" type="text/css" href="css/main.css" /> 
  
    <script type="text/javascript" src="js/main.js"></script> 
  
</head> 
  
 <body> 
  
    <div class="example"> 
  
        <div id="main_object"> 
  
            <div class="tl"><img alt="" src="image.jpg"></div> 
  
            <div class="tr"><img alt="" src="image.jpg"></div> 
  
            <div class="bl"><img alt="" src="image.jpg"></div> 
  
            <div class="br"><img alt="" src="image.jpg"></div> 
  
        </div> 
  
    </div> 
  
 </body> 
  
</html>

Here are main object with 4 images inside

Step 2. CSS

Here are single CSS file with all necessary styles:

css/main.css

body{background:#eee;margin:0;padding:0} 
  
.example{background:#FFF;width:900px;border:1px #000 solid;margin:20px auto;padding:15px;-moz-border-radius: 3px;-webkit-border-radius: 3px} 
  
#main_object{position:relative;width:900px;height:675px;overflow:hidden;cursor:pointer} 
  
#main_object div{position:absolute;overflow:hidden} 
  
#main_object img{position:absolute;-ms-interpolation-mode:nearest-neighbor} 
  
#main_object .tl,#main_object .tl img{top:0;left:0} 
  
#main_object .tr,#main_object .tr img{top:0;right:0} 
  
#main_object .bl,#main_object .bl img{bottom:0;left:0} 
  
#main_object .br,#main_object .br img{right:0;bottom:0}

Step 3. JS

Here are our main Javascript:

js/main.js

var ishk = { 
  
    // variables 
  
    speedD : .98, // degree of attenuation 
  
    speedX : 50, // speed by X 
  
    speedY : 60, // speed by X 
  
    // inner variables 
  
    xm   : 0, 
  
    ym   : 0, 
  
    sx   : 1, 
  
    sy   : 1, 
  
    svx  : 0, 
  
    svy  : 0, 
  
    xd   : 1, 
  
    yd   : 1, 
  
    drag : false, 
  
    // initialization 
  
    init : function() { 
  
        // firstly we will pass through all inner div`s and its images and collect styles 
  
        this.mobj = document.getElementById('main_object'); 
  
        var div = this.mobj.getElementsByTagName('div'); 
  
        this.d = []; 
  
        this.i = []; 
  
        for (var i = 0; i<4; i++) { 
  
            this.d[i] = div[i].style; 
  
            this.i[i] = div[i].getElementsByTagName('img')[0].style; 
  
        } 
  
        // set initial params of our generated result 
  
        this.resize(); 
  
        // prevent text selection in IE 
  
        document.onselectstart = function() { 
  
            return false; 
  
        } 
  
        // prevent IE from trying to drag an image 
  
        this.mobj.ondrag = function() { 
  
            return false; 
  
        } 
  
        // mouse down event, we will set 'drag flag to true, change cursor and positions 
  
        this.mobj.onmousedown = function() { 
  
            ishk.drag = true; 
  
            ishk.mobj.style.cursor = 'move'; 
  
            ishk.xd = ishk.xm - ishk.nx; 
  
            ishk.yd = ishk.ym - ishk.ny; 
  
            return false; 
  
        } 
  
        // on mouse up - release 'drag' flag, change pointer 
  
        document.onmouseup = function() { 
  
            ishk.drag = false; 
  
            ishk.mobj.style.cursor = 'pointer'; 
  
            return false; 
  
        } 
  
        // set max sizes to last image 
  
        this.i[3].width =  ishk.nw; 
  
        this.i[3].height = ishk.nh; 
  
        // and initial positions too 
  
        ishk.sx = ishk.nx; 
  
        ishk.sy = ishk.ny; 
  
        // start looping 
  
        this.shake(); 
  
    }, 
  
    // refreshing mouse positions 
  
    mousemove : function(e) { 
  
        this.xm = e.clientX; 
  
        this.ym = e.clientY; 
  
    }, 
  
    // sub init of initial positions, plus, in case of window resizing - repeat too 
  
    resize : function() { 
  
        var o = ishk.mobj; 
  
        for (ishk.nx = 0, ishk.ny = 0; o != null; o = o.offsetParent) 
  
            ishk.nx += o.offsetLeft, ishk.ny += o.offsetTop; 
  
        ishk.nw = ishk.mobj.offsetWidth; 
  
        ishk.nh = ishk.mobj.offsetHeight; 
  
    }, 
  
    // main shaking function 
  
    shake : function() { 
  
        // in case of mouse move and dragging - change center position 
  
        if (ishk.drag) { 
  
            ishk.sx = ishk.xm; 
  
            ishk.sy = ishk.ym; 
  
        } else { // otherwise - attenuation 
  
            ishk.svx = ishk.speedD * ishk.svx - (ishk.sx - ishk.xd - ishk.nx) / ishk.speedX; 
  
            ishk.svy = ishk.speedD * ishk.svy - (ishk.sy - ishk.yd - ishk.ny) / ishk.speedY; 
  
            ishk.sx += ishk.svx; 
  
            ishk.sy += ishk.svy; 
  
        } 
  
        // calculation new widths and heights of our div`s and images 
  
        var w0 = Math.max(0, Math.round(ishk.sx) - ishk.nx); 
  
        var h0 = Math.max(0, Math.round(ishk.sy) - ishk.ny); 
  
        var w1 = Math.max(0, ishk.nw - (Math.round(ishk.sx) - ishk.nx)); 
  
        var h1 = Math.max(0, ishk.nh - (Math.round(ishk.sy) - ishk.ny)); 
  
        var w2 = Math.max(0, Math.round((w0 * ishk.nw) / ishk.xd)); 
  
        var h2 = Math.max(0, Math.round((h0 * ishk.nh) / ishk.yd)); 
  
        var w3 = Math.max(0, Math.round((w1 * ishk.nw) / (ishk.nw - ishk.xd))); 
  
        var h3 = Math.max(0, Math.round((h1 * ishk.nh) / (ishk.nh - ishk.yd))); 
  
        // apply new widths 
  
        ishk.d[0].width = w0 + 'px'; 
  
        ishk.d[1].width = w1 + 'px'; 
  
        ishk.d[2].width = w0 + 'px'; 
  
        ishk.d[3].width = w1 + 'px'; 
  
        ishk.d[0].height = h0 + 'px'; 
  
        ishk.d[1].height = h0 + 'px'; 
  
        ishk.d[2].height = h1 + 'px'; 
  
        ishk.d[3].height = h1 + 'px'; 
  
        ishk.i[0].width = w2 + 'px'; 
  
        ishk.i[1].width = w3 + 'px'; 
  
        ishk.i[2].width = w2 + 'px'; 
  
        ishk.i[3].width = w3 + 'px'; 
  
        ishk.i[0].height = h2 + 'px'; 
  
        ishk.i[1].height = h2 + 'px'; 
  
        ishk.i[2].height = h3 + 'px'; 
  
        ishk.i[3].height = h3 + 'px'; 
  
        // looping current function 
  
        setTimeout(ishk.shake, 20); // 1/50*1000 = 20ms (for 50 fps) :) 
  
    } 
  
}; 
  
window.onload = function() { 
  
    ishk.init(); // first initialization 
  
    // binding mouse move event 
  
    document.onmousemove = function(e) { 
  
        if (window.event) e = window.event; // for IE 
  
        ishk.mousemove(e); 
  
    } 
  
    // binding onresize event 
  
    window.onresize = ishk.resize; 
  
}

It is rather simple. When the page loads – I initialize our main object, and link all the necessary events. Then, after initialization, I loop our main ‘shake’ function, which changing sizes of all our 4 images (sectors).

Step 4. Images

For our demo I used only one image:

Live Demo

Conclusion

Today I told you how to create easy shaking effect to images. Commonly – you can try to play with any another objects too. Hope our javascript lessons still interesting for you. Good luck!