src/rgbquant.js
function distManhattan(rgb0, rgb1) {
		var rd = Math.abs(rgb1[0]-rgb0[0]),
			gd = Math.abs(rgb1[1]-rgb0[1]),
			bd = Math.abs(rgb1[2]-rgb0[2]);

		return (Pr*rd + Pg*gd + Pb*bd) / manhMax;
	}
function distManhattan(rgb0, rgb1) {
		var rd = Math.abs(rgb1[0]-rgb0[0]),
			gd = Math.abs(rgb1[1]-rgb0[1]),
			bd = Math.abs(rgb1[2]-rgb0[2]);

		return (Pr*rd + Pg*gd + Pb*bd) / manhMax;
	}
function distManhattan ( rgb0 , rgb1 ) { var rd = Math . abs ( rgb1 [ 0 ] - rgb0 [ 0 ] ) , gd = Math . abs ( rgb1 [ 1 ] - rgb0 [ 1 ] ) , bd = Math . abs ( rgb1 [ 2 ] - rgb0 [ 2 ] ) ; return ( Pr * rd + Pg * gd + Pb * bd ) / manhMax ; }
perceptual Manhattan color distance
perceptual Manhattan color distance