🚀 go-pugleaf

I'm an inexperienced DOS programmer, so please forgive any stupidity...

I have a little "windowing" package I've written; when you open up a window
on top of another, it saves the contents of the window(s) behind it by
reading the ASCII/color bytes from the display buffer, and socks it away
for restoration after the window is closed. THE PROBLEM is that this technique
only would work in "text" mode, not in one of the various graphics modes
where characters are painted to the screen.

Short of saving much larger graphic buffers when opening up a window on a
graphics screen, what might I do to preserve windows behind? Does the text &
color information get shadowed somewhere that I can read? Should I write
output rroutines that do some sort of shadowing myself? Or perhaps abandon
the whole plan and write my program such that windows get "update" events
as on the Mac?  Any suggestions would be appreciated.