DVT SystemVerilog IDE User Guide
Rev. 19.1.34, 11 October 2019
There might be two kinds of errors related to Graphviz:
1. Graphviz is not (correctly) installed.
You can get graphviz from http://www.graphviz.org/Download.php, either as a package for your distribution or as source tarball.
2. Graphviz does not support png format.
The problem might be related to the formats supported by the Graphviz package you have installed. DVT works with png format.
To find out if your installation supports png, please issue this command in a shell:
and check if png is among the list of supported formats.
If not, this can be easily solved by installing the package called graphviz-gd that adds png support to your current Graphviz installation. The official download location is here: http://www.graphviz.org/Download.php - you just have to select the one matching your OS version & architecture.