(function($) {
var has_VML, create_canvas_for, add_shape_to, clear_canvas, shape_from_area,
canvas_style, fader, hex_to_decimal, css3color, is_image_loaded;

has_VML = document.namespaces;
has_canvas = document.createElement('canvas');
has_canvas = has_canvas && has_canvas.getContext;

if(!(has_canvas || has_VML)) {
$.fn.maphilight = function() { return this; };
return;
}

if(has_canvas) {
fader = function(element, opacity, interval) {
if(opacity <= 1) {
element.style.opacity = opacity;
window.setTimeout(fader, 10, element, opacity + 0.1, 10);
}
};

hex_to_decimal = function(hex) {
return Math.max(0, Math.min(parseInt(hex, 16), 255));
};
css3color = function(color, opacity) {
return 'rgba('+hex_to_decimal(color.substr(0,2))+','+hex_to_decimal(color.substr(2,2))+','+hex_to_decimal(color.substr(4,2))+','+opacity+')';
};
create_canvas_for = function(img) {
var c = $('<canvas style="width:'+img.width+'px;height:'+img.height+'px;"></canvas>').get(0);
c.getContext("2d").clearRect(0, 0, c.width, c.height);
return c;
};
add_shape_to = function(canvas, shape, coords, options, name) {
var i, context = canvas.getContext('2d');
context.beginPath();
if(shape == 'rect') {
context.rect(coords[0], coords[1], coords[2] - coords[0], coords[3] - coords[1]);
} else if(shape == 'poly') {
context.moveTo(coords[0], coords[1]);
for(i=2; i < coords.length; i+=2) {
context.lineTo(coords[i], coords[i+1]);
}
} else if(shape == 'circ') {
context.arc(coords[0], coords[1], coords[2], 0, Math.PI * 2, false);
}
context.closePath();
if(options.fill) {
context.fillStyle = css3color(options.fillColor, options.fillOpacity);
context.fill();
}
if(options.stroke) {
context.strokeStyle = css3color(options.strokeColor, options.strokeOpacity);
context.lineWidth = options.strokeWidth;
context.stroke();
}
if(options.fade) {
fader(canvas, 0);
}
};
clear_canvas = function(canvas, area) {
canvas.getContext('2d').clearRect(0, 0, canvas.width,canvas.height);
};
} else { // ie executes this code
create_canvas_for = function(img) {
return $('<var style="zoom:1;overflow:hidden;display:block;width:'+img.width+'px;height:'+img.height+'px;"></var>').get(0);
};
add_shape_to = function(canvas, shape, coords, options, name) {
var fill, stroke, opacity, e;
fill = '<v:fill color="#'+options.fillColor+'" opacity="'+(options.fill ? options.fillOpacity : 0)+'" />';
stroke = (options.stroke ? 'strokeweight="'+options.strokeWidth+'" stroked="t" strokecolor="#'+options.strokeColor+'"' : 'stroked="f"');
opacity = '<v:stroke opacity="'+options.strokeOpacity+'"/>';
if(shape == 'rect') {
e = $('<v:rect name="'+name+'" filled="t" '+stroke+' style="zoom:1;margin:0;padding:0;display:block;position:absolute;left:'+coords[0]+'px;top:'+coords[1]+'px;width:'+(coords[2] - coords[0])+'px;height:'+(coords[3] - coords[1])+'px;"></v:rect>');
} else if(shape == 'poly') {
e = $('<v:shape name="'+name+'" filled="t" '+stroke+' coordorigin="0,0" coordsize="'+canvas.width+','+canvas.height+'" path="m '+coords[0]+','+coords[1]+' l '+coords.join(',')+' x e" style="zoom:1;margin:0;padding:0;display:block;position:absolute;top:0px;left:0px;width:'+canvas.width+'px;height:'+canvas.height+'px;"></v:shape>');
} else if(shape == 'circ') {
e = $('<v:oval name="'+name+'" filled="t" '+stroke+' style="zoom:1;margin:0;padding:0;display:block;position:absolute;left:'+(coords[0] - coords[2])+'px;top:'+(coords[1] - coords[2])+'px;width:'+(coords[2]*2)+'px;height:'+(coords[2]*2)+'px;"></v:oval>');
}
e.get(0).innerHTML = fill+opacity;
$(canvas).append(e);
};
clear_canvas = function(canvas) {
$(canvas).find('[name=highlighted]').remove();
};
}

shape_from_area = function(area) {
var i, coords = area.getAttribute('coords').split(',');
for (i=0; i < coords.length; i++) { coords[i] = parseFloat(coords[i]); }
return [area.getAttribute('shape').toLowerCase().substr(0,4), coords];
};

is_image_loaded = function(img) {
if(!img.complete) { return false; } // IE
if(typeof img.naturalWidth != "undefined" && img.naturalWidth == 0) { return false; } // Others
return true;
}

canvas_style = {
position: 'absolute',
left: 0,
top: 0,
padding: 0,
border: 0
};

var ie_hax_done = false;
$.fn.maphilight = function(opts) {
opts = $.extend({}, $.fn.maphilight.defaults, opts);

if($.browser.msie && !ie_hax_done) {
document.namespaces.add("v", "urn:schemas-microsoft-com:vml");
var style = document.createStyleSheet();
var shapes = ['shape','rect', 'oval', 'circ', 'fill', 'stroke', 'imagedata', 'group','textbox'];
$.each(shapes,
function() {
style.addRule('v\\:' + this, "behavior: url(#default#VML); antialias:true");
}
);
ie_hax_done = true;
}

return this.each(function() {
var img, wrap, options, map, canvas, canvas_always, mouseover, highlighted_shape;
img = $(this);

if(!is_image_loaded(this)) {
// If the image isn't fully loaded, this won't work right. Try again later.
return window.setTimeout(function() {
img.maphilight(opts);
}, 200);
}

options = $.metadata ? $.extend({}, opts, img.metadata()) : opts;

map = $('map[name="'+img.attr('usemap').substr(1)+'"]');

if(!(img.is('img') && img.attr('usemap') && map.size() > 0)) { return; }

if(img.hasClass('maphilighted')) {
// We're redrawing an old map, probably to pick up changes to the options.
// Just clear out all the old stuff.
var wrapper = img.parent();
img.insertBefore(wrapper);
wrapper.remove();
}

wrap = $('<div class="'+$(this).attr('class')+'"></div>').css({
                display:'block',
                background:'url('+this.src+')',
                position:'relative',
                padding:0,
                width:this.width,
                height:this.height
                });
img.before(wrap).css('opacity', 0).css(canvas_style).remove();
if($.browser.msie) { img.css('filter', 'Alpha(opacity=0)'); }
wrap.append(img);

canvas = create_canvas_for(this);
$(canvas).css(canvas_style);
canvas.height = this.height;
canvas.width = this.width;

mouseover = function(e) {
var shape, area_options;
area_options = $.metadata ? $.extend({}, options, $(this).metadata()) : options;
if(
!area_options.neverOn
&&
!area_options.alwaysOn
/*&&
// .is(':visible') doesn't work on <area>s, interestingly. Always says true
$(this).css('display') != 'none'*/
) {
shape = shape_from_area(this);
add_shape_to(canvas, shape[0], shape[1], area_options, "highlighted");
}
}

if(options.alwaysOn) {
$(map).find('area[coords]').each(mouseover);
} else {
if($.metadata) {
// If the metadata plugin is present, there may be areas with alwaysOn set.
// We'll add these to a *second* canvas, which will get around flickering during fading.
$(map).find('area[coords]').each(function() {
var shape, area_options;
area_options = $.metadata ? $.extend({}, options, $(this).metadata()) : options;
if(area_options.alwaysOn) {
if(!canvas_always) {
canvas_always = create_canvas_for(img.get());
$(canvas_always).css(canvas_style);
canvas_always.width = img.width();
canvas_always.height = img.height();
img.before(canvas_always);
}
shape = shape_from_area(this);
if ($.browser.msie) {
add_shape_to(canvas, shape[0], shape[1], area_options, "");
} else {
add_shape_to(canvas_always, shape[0], shape[1], area_options, "");
}
}
});
}
$(map).find('area[coords]').mouseover(mouseover).mouseout(function(e) { clear_canvas(canvas); });
}

img.before(canvas); // if we put this after, the mouseover events wouldn't fire.

img.addClass('maphilighted');
});
};
$.fn.maphilight.defaults = {
fill: true,
fillColor: '000000',
fillOpacity: 0.2,
stroke: true,
strokeColor: 'ff0000',
strokeOpacity: 1,
strokeWidth: 1,
fade: true,
alwaysOn: false,
neverOn: false
};
})(jQuery);