tree 23f6e3fd71e1e0e1ce81a4faec37508ac6435d9b
parent 30b84f5caded640843b4b07bd734889f385778f0
author Bill Evans <Bill@8PawExpress.com> 1599843506 -0700
committer Bill Evans <Bill@8PawExpress.com> 1599843506 -0700

fix #517 and #518, empty data and empty img tags

- return NULL if x is empty/null, no need to try to plot something
- check for this NULL when saving to html or latex