jSketch

$(function() {

    var $sketcher = $('#drawing-canvas').sketchable();

    function resizeHandler(elem, data) {
      var newWidth = elem.parent().width() * 0.95;
      data.sketch.size(newWidth, elem.height());
    }

    $(window).resize(function(ev) {
      $sketcher.sketchable('handler', resizeHandler);
    });

    $sketcher.sketchable('handler', resizeHandler);

});