message: Issue - fix for negative chart colors
diff: @@ -2349,6 +2349,7 @@ var PptxGenJS = function(){
  function makeChartType(chartType, data, opts, valAxisId, catAxisId) {
  var strXml = '';
  +
  switch ( chartType ) {
  case 'area':
  case 'bar':
  @@ -2374,7 +2375,7 @@ var PptxGenJS = function(){
  ]
  */
  - // maintain the color index by region:
  + // NOTE: Maintain the color index by region
  var colorIndex = -1;
  data.forEach(function(obj){
  colorIndex++;
  @@ -2443,11 +2444,11 @@ var PptxGenJS = function(){
  if (( data.length === 1 || opts.valueBarColors ) && opts.chartColors != BARCHART_COLORS ) {
  // Series Data Point colors
  obj.values.forEach(function(value,index){
  - var invert = opts.invertedColors ? 0 : 1;
  - var colors = (value < 0 ? opts.invertedColors : opts.chartColors);
  + var arrColors = (value < 0 ? (opts.invertedColors || BARCHART_COLORS) : opts.chartColors);
  +
  strXml += ' <c:dPt>';
  strXml += ' <c:idx val="'+ index +'"/>';
  - strXml += ' <c:invertIfNegative val="'+invert+'"/>';
  + strXml += ' <c:invertIfNegative val="'+ (opts.invertedColors ? 0 : 1) +'"/>';
  strXml += ' <c:bubble3D val="0"/>';
  strXml += ' <c:spPr>';
  if ( opts.lineSize === 0 ){
  @@ -2455,7 +2456,7 @@ var PptxGenJS = function(){
  }
  else {
  strXml += '<a:solidFill>';
  - strXml += ' <a:srgbClr val="'+(colors[index % colors.length])+'"/>';
  + strXml += ' <a:srgbClr val="'+ arrColors[index % arrColors.length] +'"/>';
  strXml += '</a:solidFill>';
  }
  strXml += createShadowElement(opts.shadow, DEF_SHAPE_SHADOW);
  