title: controlling the resolution (dpi) of an exported JPG from highcharts exporting-server
body: <p>I have read the recent posts on the Highcharts.com website regarding their updated PhantomJS based exporting-server. I have also cloned their github repository and successfully compiled their web-service. However, all files produced by this server are marked as 96dpi, which is inadequate for my purposes. According to somewhat contradictory information on the Highcharts.com website (<a href="http://www.highcharts.com/component/content/article/2-news/52-serverside-generated-charts" rel="nofollow">Here</a> and <a href="http://www.highcharts.com/component/content/article/2-news/56-improved-image-export-with-phantomjs" rel="nofollow">Here</a>), they are using Batik to rasterize PNG and JPG output, which should make it possible to adjust the DPI settings of the exported raster images. However, the pom.xml doesn't include any batik references and I can't find anything in the source code which indicates that anything other than PhantomJS is being used to produce the raster renditions.  The PhantomJS export might be able to adjust the DPI, but I can only find the scale and width options which don't directly adjust the DPI, thus requiring a tedious post-processing rescale (or metadata edit) to adjust the DPI accordingly.</p>
  
  <p>So, the meat of my question: how to adjust the exported DPI of a highcharts chart in PNG and JPG format when using the highcharts java exporting-server?</p>