jQM - Center content image

by Dragan Gaić

HTML

<link rel="stylesheet" href="http://jeromeetienne.github.com/jquery-mobile-960/css/jquery-mobile-fluid960.css">
<script src="http://timeago.yarp.com/jquery.timeago.js"></script>
<script src="http://imakewebthings.github.com/jquery-waypoints/waypoints.min.js"></script>
<!DOCTYPE html>
<html>
    <head>
        <title>jQM Complex Demo</title>
        <meta name="viewport" content="width=device-width; initial-scale=1.0; maximum-scale=1.0; minimum-scale=1.0; user-scalable=no; target-densityDpi=device-dpi"/>
        <link rel="stylesheet" href="http://code.jquery.com/mobile/1.2.0/jquery.mobile-1.2.0.min.css" />
        <script src="http://code.jquery.com/mobile/1.2.0/jquery.mobile-1.2.0.min.js"></script>    
    </head>
    <body>
        <div data-role="page" id="index">
            <div data-theme="a" data-role="header">
                <h3>
                    First Page
                </h3>
                <a href="#second" class="ui-btn-right">Next</a>
            </div>
            
            <div data-role="content">
                <div class="ui-center-image">
                    <img src="http://www.wholelifepetsblog.com/wp-content/uploads/2012/11/cute-puppy.jpg" height="100%" width="auto"/> 
                </div>
            </div>
            
            <div data-theme="a" data-role="footer" data-position="fixed">
                <h3>
                    Footer
                </h3>
            </div>
        </div>    
    </body>
</html>

CSS

html,body{height:100%;}

img {
    padding: 0 !important;
    margin: 0 !important;
    border: 0 !important;
    overflow-y: hidden !important;
}

.ui-content {
    padding: 0 !important;
}

.ui-center-image {
    margin-left: auto;
    margin-right: auto;
    position: relative;
    display: block;
    height: 100%;
}

.ui-content .ui-center-image img {  
    max-height: 100%;/* Part 1: Set a maxium relative to the parent */
    width: auto\9;
    /* IE7-8 need help adjusting responsive images */
    max-width: auto; 
    /* Part 2: Scale the height according to the width, otherwise you get stretching */
    vertical-align: middle;
    border: 0;
    -ms-interpolation-mode: bicubic;
}

JavaScript

$(document).on('pageshow', '#index', function(){       
    $('[data-role="content"]').height(getRealContentHeight());
    $('.ui-center-image').width($('.ui-content .ui-center-image img').width());
});

function getRealContentHeight() {
    var header = $.mobile.activePage.find("div[data-role='header']:visible");
    var footer = $.mobile.activePage.find("div[data-role='footer']:visible");
    var content = $.mobile.activePage.find("div[data-role='content']:visible:visible");
    var viewport_height = $(window).height();

    var content_height = viewport_height - header.outerHeight() - footer.outerHeight();
    if((content.outerHeight() - header.outerHeight() - footer.outerHeight()) <= viewport_height) {
        content_height -= (content.outerHeight() - content.height());
    } 
    return content_height;
}