I posted it already in the Development section, but the content evolved in a powerful tool.
Beware, it's not very small but there's a lot of stuff to play with and it's way faster than the BASIC routines!
viewtopic.php?p=47317#p47317
Enhancement for lo-rez graphics and effects
Re: Enhancement for lo-rez graphics and effects
Thanks Stefano.
Xavier ...on the Facebook groupe : "Zx81 France"(fr)