Одним из решений является изменение jQuery-плагина Responsive Image Maps, сделав предков видимыми перед вызовом width ().
Оригинальный код:
/*
* rwdImageMaps jQuery plugin v1.6
*
* Allows image maps to be used in a responsive design by recalculating the area coordinates to match the actual image size on load and window.resize
*
* Copyright (c) 2016 Matt Stow
* https://github.com/stowball/jQuery-rwdImageMaps
* http://mattstow.com
* Licensed under the MIT license
*/
;(function($) {
$.fn.rwdImageMaps = function() {
var $img = this;
var rwdImageMap = function() {
$img.each(function() {
if (typeof($(this).attr('usemap')) == 'undefined')
return;
var that = this,
$that = $(that);
// Since WebKit doesn't know the height until after the image has loaded, perform everything in an onload copy
$('<img />').on('load', function() {
var attrW = 'width',
attrH = 'height',
w = $that.attr(attrW),
h = $that.attr(attrH);
if (!w || !h) {
var temp = new Image();
temp.src = $that.attr('src');
if (!w)
w = temp.width;
if (!h)
h = temp.height;
}
var wPercent = $that.width()/100,
hPercent = $that.height()/100,
map = $that.attr('usemap').replace('#', ''),
c = 'coords';
$('map[name="' + map + '"]').find('area').each(function() {
var $this = $(this);
if (!$this.data(c))
$this.data(c, $this.attr(c));
var coords = $this.data(c).split(','),
coordsPercent = new Array(coords.length);
for (var i = 0; i < coordsPercent.length; ++i) {
if (i % 2 === 0)
coordsPercent[i] = parseInt(((coords[i]/w)*100)*wPercent);
else
coordsPercent[i] = parseInt(((coords[i]/h)*100)*hPercent);
}
$this.attr(c, coordsPercent.toString());
});
}).attr('src', $that.attr('src'));
});
};
$(window).resize(rwdImageMap).trigger('resize');
return this;
};
})(jQuery);
Модифицированный код:
/*
* rwdImageMaps jQuery plugin v1.6
*
* Allows image maps to be used in a responsive design by recalculating the area coordinates to match the actual image size on load and window.resize
*
* Copyright (c) 2016 Matt Stow
* https://github.com/stowball/jQuery-rwdImageMaps
* http://mattstow.com
* Licensed under the MIT license
*/
;(function($) {
$.fn.rwdImageMaps = function() {
var $img = this;
var rwdImageMap = function() {
$img.each(function() {
if (typeof($(this).attr('usemap')) == 'undefined')
return;
var that = this,
$that = $(that);
// Since WebKit doesn't know the height until after the image has loaded, perform everything in an onload copy
$('<img />').on('load', function() {
// Modif BC : make ancestors visible so .width() can return the right value
//************************************************
var hidden_ancestors = [];
$that.parents().each(function() {
if ($(this).css('display') == 'none')
{
$(this).show();
hidden_ancestors.push($(this));
};
});
// END Modif BC
var attrW = 'width',
attrH = 'height',
w = $that.attr(attrW),
h = $that.attr(attrH);
if (!w || !h) {
var temp = new Image();
temp.src = $that.attr('src');
if (!w)
w = temp.width;
if (!h)
h = temp.height;
}
var wPercent = $that.width()/100,
hPercent = $that.height()/100,
map = $that.attr('usemap').replace('#', ''),
c = 'coords';
$('map[name="' + map + '"]').find('area').each(function() {
var $this = $(this);
if (!$this.data(c))
$this.data(c, $this.attr(c));
var coords = $this.data(c).split(','),
coordsPercent = new Array(coords.length);
for (var i = 0; i < coordsPercent.length; ++i) {
if (i % 2 === 0)
coordsPercent[i] = parseInt(((coords[i]/w)*100)*wPercent);
else
coordsPercent[i] = parseInt(((coords[i]/h)*100)*hPercent);
}
$this.attr(c, coordsPercent.toString());
});
// Modif BC : Restore invisibility on ancestors
//*********************************************
jQuery.each(hidden_ancestors, function(index, value)
{
$(value).css({display: ''});
});
// END Modif BC
}).attr('src', $that.attr('src'));
});
};
$(window).resize(rwdImageMap).trigger('resize');
return this;
};
})(jQuery);
Я предложу это усовершенствование Мэтту Стоу, автору