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SYS(602): current thinking
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From
23/05/2022 21:00:29
John Ryan
Captain-Cooker Appreciation Society
Taumata Whakatangi ..., New Zealand
 
 
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Forum:
Visual FoxPro
Category:
Coding, syntax & commands
Title:
SYS(602): current thinking
Miscellaneous
Thread ID:
01684392
Message ID:
01684392
Views:
88
All,

I'd be interested to know latest thoughts on SYS(602) bitmap configuration under terminal services.

Standard VFP does refreshes using off-screen bitmaps that get snapped onto the visible screen for crisp refreshes; however, since this uses "a lot of memory" we were told that when using TS it's good practice to use SYS(602) to turn this feature off.

However: I have an app using backstyle_access in a grid control to deliver dynamic row appearance. Under RTS with off-screen bitmap off using sys(602), the grid flashes and flickers unpredictably. No problem with standard bitmap setting. I have experimented with set focus and similar, but the flickering continues intermittently if off-screen bitmaps are off.

VFP's use of memory seems very low regardless, so I would leave the setting on- except it was also suggested in one of the guru VFP books that VFP's standard bitmap behaviour can send a deluge of updates down the wire; I suppose that could be true if the whole screen gets refreshed every time compared to just updating the changes.

Does anybody have updated info on this?
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us.
"
-- Shakespeare: Coriolanus, Act 1, scene 1
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