// Contributors
// Ilkka Huotari at http://www.editsite.net
// Mathieu 'p01' HENRI at http://www.p01.org/
// http://seky.nahory.net/2005/04/rounded-corners/
// Steven Wittens at http://www.acko.net/anti-aliased-nifty-corners
// Original Nifty Corners by Alessandro Fulciniti at http://pro.html.it/esempio/nifty/
function NiftyCheck()
{
    if (!document.getElementById || !document.createElement)
	{
        return false;
    }

    var b = navigator.userAgent.toLowerCase();

    if (b.indexOf("msie 5") > 0 && b.indexOf("opera") == -1)
	{
        return false;
    }

    return true;
}

function Rounded(className, sizex, sizey, sizex_b, sizey_b)
{
    var bk;

    if (!NiftyCheck())
		return;
		
    if (typeof(sizex_b) == 'undefined')
    	sizex_b = sizex;

    if (typeof(sizey_b) == 'undefined')
    	sizey_b = sizey;

    var v = getElements(className);
    var l = v.length;

    for (var i = 0; i < l; i++)
	{
        color = get_current_style(v[i], "background-color", "transparent");
        bk = get_current_style(v[i].parentNode, "background-color", "transparent");
        AddRounded(v[i], bk, color, sizex, sizey, true);
        AddRounded(v[i], bk, color, sizex_b, sizey_b, false);
    }
}

Math.sqr = function(x)
{
    return x * x;
};

function Blend(a, b, alpha)
{
    var ca = Array(
    	parseInt('0x' + a.substring(1, 3)),
    	parseInt('0x' + a.substring(3, 5)),
    	parseInt('0x' + a.substring(5, 7))
    );

    var cb = Array(
    	parseInt('0x' + b.substring(1, 3)),
    	parseInt('0x' + b.substring(3, 5)),
    	parseInt('0x' + b.substring(5, 7))
    );

    return '#' + ('0' + Math.round(ca[0] + (cb[0] - ca[0]) * alpha).toString(16)).slice( - 2).toString(16)
    	+ ('0' + Math.round(ca[1] + (cb[1] - ca[1]) * alpha).toString(16)).slice( - 2).toString(16)
    	+ ('0' + Math.round(ca[2] + (cb[2] - ca[2]) * alpha).toString(16)).slice( - 2).toString(16);

    return '#' + ('0' + Math.round(ca[0] + (cb[0] - ca[0]) * alpha).toString(16)).slice( - 2).toString(16)
    	+ ('0' + Math.round(ca[1] + (cb[1] - ca[1]) * alpha).toString(16)).slice( - 2).toString(16)
    	+ ('0' + Math.round(ca[2] + (cb[2] - ca[2]) * alpha).toString(16)).slice( - 2).toString(16);
}

function AddRounded(el, bk, color, sizex, sizey, top)
{
    if (!sizex && !sizey)
    	return;

    var i, j;
    var d = document.createElement("div");
    d.style.backgroundColor = bk;
    var lastarc = 0;

    for (i = 1; i <= sizey; i++)
	{
        var coverage,
        arc2,
        arc3;
    
    	// Find intersection of arc with bottom of pixel row
        arc = Math.sqrt(1.0 - Math.sqr(1.0 - i / sizey)) * sizex;
        
		// Calculate how many pixels are bg, fg and blended.
        var n_bg = sizex - Math.ceil(arc);
        var n_fg = Math.floor(lastarc);
        var n_aa = sizex - n_bg - n_fg;
        
		// Create pixel row wrapper
        var x = document.createElement("div");
        var y = d;
        x.style.margin = "0px " + n_bg + "px";
        x.style.height = '1px';
        x.style.overflow = 'hidden';
        
		// Make a wrapper per anti-aliased pixel (at least one)
        for (j = 1; j <= n_aa; j++)
		{
            // Calculate coverage per pixel
            // (approximates circle by a line within the pixel)
            if (j == 1)
			{
                if (j == n_aa)
				{
                    // Single pixel
                    coverage = ((arc + lastarc) * .5) - n_fg;
                }
                else
				{
                    // First in a run
                    arc2 = Math.sqrt(1.0 - Math.sqr((sizex - n_bg - j + 1) / sizex)) * sizey;
                    coverage = (arc2 - (sizey - i)) * (arc - n_fg - n_aa + 1) * .5;
                
    				// Coverage is incorrect. Why?
                    coverage = 0;
                }
            }
            else if (j == n_aa)
			{
                // Last in a run
                arc2 = Math.sqrt(1.0 - Math.sqr((sizex - n_bg - j + 1) / sizex)) * sizey;
                coverage = 1.0 - (1.0 - (arc2 - (sizey - i))) * (1.0 - (lastarc - n_fg)) * .5;
            }
            else
			{
                // Middle of a run
                arc3 = Math.sqrt(1.0 - Math.sqr((sizex - n_bg - j) / sizex)) * sizey;
                arc2 = Math.sqrt(1.0 - Math.sqr((sizex - n_bg - j + 1) / sizex)) * sizey;
                coverage = ((arc2 + arc3) * .5) - (sizey - i);
            }

            x.style.backgroundColor = Blend(bk, color, coverage);

            if (top)
            	y.appendChild(x);
            else
            	y.insertBefore(x, y.firstChild);

            y = x;
            var x = document.createElement("div");
            x.style.height = '1px';
            x.style.overflow = 'hidden';
            x.style.margin = "0px 1px";
        }

        x.style.backgroundColor = color;

        if (top)
        	y.appendChild(x);
        else
        	y.insertBefore(x, y.firstChild);

        lastarc = arc;
    }

    if (top)
    	el.insertBefore(d, el.firstChild);
    else
    	el.appendChild(d);
}

function getElements(className)
{
    var elements = [];
    var el = document.getElementsByTagName('DIV');
    var regexp = new RegExp("\\b" + className + "\\b");

    for (var i = 0; i < el.length; i++)
    {
        if (regexp.test(el[i].className))
        	elements.push(el[i]);
    }

    return elements;
}

function get_current_style(element, property, not_accepted)
 {
    var ee,
    i,
    val,
    apr;
    
	try
    {
        var cs = document.defaultView.getComputedStyle(element, '');
        val = cs.getPropertyValue(property);
    }
    catch(ee)
    {
        if (element.currentStyle)
        {
            apr = property.split("-");
            for (i = 1; i < apr.length; i++)
				apr[i] = apr[i].toUpperCase();
				
            apr = apr.join("");
            val = element.currentStyle.getAttribute(apr);
        }
    }
    
	if ((val.indexOf("rgba") > -1 || val == not_accepted) && element.parentNode)
    {
        if (element.parentNode != document)
        	val = get_current_style(element.parentNode, property, not_accepted);
        else
        	val = '#FFFFFF';
    }

    if (val.indexOf("rgb") > -1 && val.indexOf("rgba") == -1)
    	val = rgb2hex(val);
    if (val.length == 4)
    	val = '#' + val.substring(1, 1) + val.substring(1, 1) + val.substring(2, 1) + val.substring(2, 1) + val.substring(3, 1) + val.substring(3, 1);

    return val;
}

function rgb2hex(value)
{
    var x = 255;
    var hex = '';
    var i;
    var regexp = /([0-9]+)[, ]+([0-9]+)[, ]+([0-9]+)/;
    var array = regexp.exec(value);

    for (i = 1; i < 4; i++)
		hex += ('0' + parseInt(array[i]).toString(16)).slice( - 2);
		
    return '#' + hex;
}