When I started writing the Game Library, it was originally only a Graphics Library. The first thing I did was to get the Z88DK Devkit to display writing in fonts in the VZ’s hires MODE(1) graphics mode.
I was looking at a game sample and also playing around with a sprite editor called Spedito. I discovered that the format Spedito exports sprite data in can be used with the Z88DK to display monographic sprite data and could be programmed to display text fonts created in Spedito.
I set about writing Foxglovz which would draw text on the screen. It took a lot of learning as I have mostly written only a few basic programs in C over the years. The guys on the Z88DK forum were extremely helpful and patient with a newbie like me.
After some time I had it drawing text in any of the VZ colours and added on the ability to automatically draw an underline if required.

I thought I might share a few thoughts while developing my Z80 Game Engine for the VZ200/VZ300 computers (aka VTech Laser 200 / Salora Fellow / Seltron 200 / etc). These computers have a Zilog Z80 CPU and a Motorola 6847 graphics chip.
I recently started using the Z88DK devkit which allows you to code Z80 applications using C and you can also use Z80 Assembly either inline or as addon files.