RE: Window overlay problem

["Larry Ducie" <larry_ducie@xxxxxxxxxxx>]

Steven,

I know I'm probably late to the game but I thought I'd add my thoughts to 
this one.

I have always coded my window definitions as follows:

(note this information is pertinent to programs that only display widows - 
and are overlaying a panel from another program, but will work for any 
window definition)

Use a dummy "panel" record format with the keywords ASSUME and OVERLAY 
specified. This will tell the operating system to assume that a panel has 
already been written to the screen and to NOT clear it when you write the 
window to the screen. You must then specify the KEEP keyword on the window 
definition (or the record format you EXFMT, that specifies the window with 
the WINDOW keyword). This is needed if you are going to ever call further 
programs that also display windows. The KEEP keyword will ensure that the 
screen doesn't flicker when any subsequent windows overlay your window - it 
will ensure that your window is kept on the screen until the next screen is 
painted. If you specify KEEP on a panel (for example the DUMMY record 
format) then the background will go black when a window from another program 
is painted to the screen and you'll be left with your two windows hanging in 
space. This is because the KEEP will be active for the whole screen (panel) 
- but you only want to keep the window - and not touch the surrounding panel 
formats. They were painted by another program so your panel KEEP will blank 
them, not keep them. Obviously, your new window program will have a dummy 
panel record format that specifies ASSUME and OVERLAY so the panels are 
protected and wont be lost.

I also specify the following DSPF additional parameters:

Enhanced display . . . . . . . .   *YES
Restore display  . . . . . . . .   *YES
Defer write  . . . . . . . . . .   *YES

By doing the above I have several panel programs that call window programs, 
that themselves call further window programs. I never get screen flicker, 
drop-out or screen loss of any kind. I can overlay any number of windows 
without problems. The look is akin to the whole application running within a 
single program.

Now you can prompt to your heart's content and splatter your screen with 
windows. <grin>

I hope this helps.

Cheers

Larry Ducie