Because of framing problems during the export, an invisible rectangle has been added, when necessary.
TBD
Graphics used in the documentation are in png format. Though this makes sens for screen snapshots this choice
is questionnable when graphics represent intrinsically vectorized
objects. This solution may change, in the future, as svg processors
used by SchemaDoc bedrock may improve.
Formerly, these graphics were designed using many editors, some
of which were not free software. Now, the Dia editor - from the Gnome project - has been favoured.
Graphics are edited whith Dia and then exported to png format, in
a "near to VGA" multi-purpose definition. Computing the final size
of the images and resizing them is left to the publishing environnement.