- Make diagram in LibreOffice.
- Save as .odg.
- Export... as .svg.
- Run:
$ inkscape theNameOf.svg \
--export-area-drawing \
--export-dpi=96 \
--export-width=DESIRED_WIDTH_PIX \
--export-height=DESIRED_HEIGHT_PIX \
--export-type=pdf \
--export-filename=theNameOf.pdf