hex_pct: uber-simple color fader

hex_pct.js

// uber-simple color fader (very limited)
// see http://jsfiddle.net/cowboy/XWaNe/

function hex_pct(base,pct){
  return base.replace( /00|ff/ig, function(a){
    var scale = 0.8,
      pct_adj = Math.max( 0, Math.min( 1, pct ) ) * scale + ( 1 - scale ) / 2,
      val = ( pct > 0.5 ? ( pct_adj - 0.5 ) : pct_adj ) * 2 * 255;
    return pct_adj != 0.5 && ( ( pct_adj > 0.5 ) == ( a == '00' ) ) ? ( '0' + parseInt(val).toString(16) ).substr(-2) : a;
  });
};


var colors = 'ff0000 00ff00 0000ff ff00ff ffff00 00ffff'.split(' ');

$.each( colors, function(i,v){
    var container = $('<div class="container"/>').appendTo('body');
    for( var pct = 0; pct <= 1; pct += 0.03 ) {
        $('<div class="color"/>')
            .text( Math.round( pct * 100 ) + '%' )
            .css( 'background', hex_pct( '#' + v, pct ) )
            .css( 'color', hex_pct( '#' + v, pct - 0.3 ) )
            .css( 'border', '1px solid ' + hex_pct( '#' + v, pct - 0.2 ) )
            .appendTo( container );
    }
});

​