javascripthtmlimagedictionaryimagemap

Dynamically resizing Image-maps and images


I'm currently trying to make an Image-Map on my site that will resize depending on the size of the window... I was wondering if there was anyway to do this with HTML or will I have to do this with Javascript or another language.

<div style="text-align:center; width:1920px; margin-left:auto; margin-right:auto;">
<img id="Image-Maps_5201211070133251" src="Site.png" usemap="#Image-Maps_5201211070133251" border="0" width="1920" height="1080" alt="" />
<map id="_Image-Maps_5201211070133251" name="Image-Maps_5201211070133251">
<area shape="poly" coords="737,116,1149,118,944,473," href="http://essper.bandcamp.com" alt="Bandcamp" title="Bandcamp"   />
<area shape="poly" coords="1006,589,1418,590,1211,945," href="http://soundcloud.com/essper" alt="Soundcloud" title="Soundcloud"   />
<area shape="poly" coords="502,590,910,591,708,944," href="http://facebook.com/the.essper" alt="Facebook" title="Facebook"   />
</map>


Solution

  • If you end up to do the task with JavaScript, here is a cross-browser codesnippet to resize all areas in MAP element.

    window.onload = function () {
        var ImageMap = function (map) {
                var n,
                    areas = map.getElementsByTagName('area'),
                    len = areas.length,
                    coords = [],
                    previousWidth = 1920;
                for (n = 0; n < len; n++) {
                    coords[n] = areas[n].coords.split(',');
                }
                this.resize = function () {
                    var n, m, clen,
                        x = document.body.clientWidth / previousWidth;
                    for (n = 0; n < len; n++) {
                        clen = coords[n].length;
                        for (m = 0; m < clen; m++) {
                            coords[n][m] *= x;
                        }
                        areas[n].coords = coords[n].join(',');
                    }
                    previousWidth = document.body.clientWidth;
                    return true;
                };
                window.onresize = this.resize;
            },
            imageMap = new ImageMap(document.getElementById('map_ID'));
        imageMap.resize();
    }
    

    previousWidth must be equal to the width of the original image. You also need to use some relative units in HTML:

    <div style="width:100%;">
    <img id="Image-Maps_5201211070133251" src="Site.png" usemap="#Image-Maps_5201211070133251" border="0" width="100%" alt="" />
    

    Working demo at jsFiddle. If you open the fiddle in IE, you can actually see AREAs when clicking them.