function hexToRgb(hex) {
    // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
    var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
    hex = hex.replace(shorthandRegex, function(m, r, g, b) {
        return r + r + g + g + b + b;
    });

    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
    return result ? {
        r: parseInt(result[1], 16),
        g: parseInt(result[2], 16),
        b: parseInt(result[3], 16)
    } : null;
}

/*
* Author : Baptiste Leulliette
* Action : Retourne la couleur décimale de la couleur Hexa.
* Date : 26 / 05
*/
function getBritghtness(R, G, B) {
	/*console.log (R + " " + G + " " + B);
	var red = R / 255;
	var green = G / 255;
	var blue = B / 255;
	if (red <= 0.03928) {
		red = red / 12.92;
	} else {
		if (red != 1) {
			red = Math.Pow (((red +0.055) / 1.055), 2.4);
		}

	}
	if (blue <= 0.03928) {
		blue = blue / 12.92;
	} else {
		if (blue != 1) {
			blue = Math.Pow (((blue +0.055) / 1.055), 2.4);
		}

	}
	if (green <= 0.03928) {
		green = green / 12.92;
	} else {
		if (green != 1 ) {
			green = Math.Pow (((green +0.055) / 1.055), 2.4);
		}

	}
	console.log("Sortie");
	var brightness =  (0.2126 * red) + (0.7152 * green) + (0.0722 * blue);
	return brightness;*/

	return ((red * 299) + (Green * 587) + (Blue * 114)) / 1000;
}

/*
* Author : Baptiste Leulliette
* Action : Calcule la difference de couleur entre la couleur de fond et le texte
* Date : 26 / 05
*/
function DisplayContrast() {
	var cPolice;
	var cFond;
	switch (color) {
		case "black":
			cPolice = "#000000";
			break;
		case "blue":
			cPolice = "#0000FF";
			break;
		case "yellow":
			cPolice = "#FFFF00";
			break;
		case "white":
			cPolice = "#FFFFFF";
			break;
		case "green":
			cPolice = "#008800";
			break;
		default:
			break;
	}

	switch (background) {
		case "black":
			cFond = "#000000";
			break;
		case "blue":
			cFond = "#0000FF";
			break;
		case "yellow":
			cFond = "#FFFF00";
			break;
		case "white":
			cFond = "#FFFFFF";
			break;
		case "green":
			cFond = "#008800";
			break;
		default:
			break;
	}

	//get des couleurs OK
	var hexPolice = hexToRgb(cPolice);
	var hexFond = hexToRgb(cFond);
	/*var lumPolice = getBritghtness(hexPolice.r, hexPolice.g, hexPolice.b);
	var lumFond = getBritghtness(hexFond.r, hexFond.g, hexFond.b);
	//Formule : Constraste = Absolute(lumFond - lumPolice) / lumFond;
	console.log("Police : " + lumPolice);
	console.log("fond : " + lumFond);*/
	var total = (maximum(hexPolice.r, hexFond.r) - minimum(hexPolice.r, hexFond.r)) + (maximum(hexPolice.g, hexFond.g) - minimum(hexPolice.g, hexFond.g)) + (maximum(hexPolice.b, hexFond.b) - minimum(hexPolice.b, hexFond.b));
	console.log(total);
	console.log("Ratio (en %) : " + total*100/765);
	console.log("Ratio suffisant (flat) = 765");
	console.log("Ratio suffisant (en %) = 84.96%");
}

function maximum (i1, i2) {
	if (i1 >= i2) {
		return i1;
	}
	return i2;
}

function minimum (i1, i2) {
	if (i1 >= i2) {
		return i2;
	}
	return i1;
}