function compress (colors, factor) {
	var data = [];

	var len = (colors.length) / factor;
	var step = (colors.length-1) / len;

	for (var i = 0; i < colors.length; i+= step) {
		data.push(colors[i|0]);
	}

	return data;
}
function compress (colors, factor) {
	var data = [];

	var len = (colors.length) / factor;
	var step = (colors.length-1) / len;

	for (var i = 0; i < colors.length; i+= step) {
		data.push(colors[i|0]);
	}

	return data;
}
function compress ( colors , factor ) { var data = [ ] ; var len = ( colors . length ) / factor ; var step = ( colors . length - 1 ) / len ; for ( var i = 0 ; i < colors . length ; i += step ) { data . push ( colors [ i | 0 ] ) ; } return data ; }
return interpolated imagedata with only each @factor pixel left
return interpolated imagedata with only each