Static image graphs in the PDF/HTML reports and Piwik Mobile app will display standard non unicode characters by default. However if you use Piwik in languages using unicode characters (Hebrew, Arabic, Japanese, Chinese, etc.), please follow the steps below:

  1. download the font unifont.ttf
  2. unzip the archive on your computer
  3. upload the file unifont.ttf in piwik/plugins/ImageGraph/fonts/unifont.ttf

Graphs in the Mobile app and Scheduled reports should now display all characters properly.

Note: the unifont.ttf will only be used for a set of languages (Japanese, Chinese, etc.). If you wish to use the font for all languages, upload the file unifont.ttf to: piwik/plugins/ImageGraph/fonts/tahoma.ttf overwriting the existing tahoma.ttf