Save Screen, Restore Screen
These obsolete
commands let you save and restore an image of any window.
Usage
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SAVE SCREEN [ TO VarName ]
RESTORE SCREEN [ FROM VarName ]
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Back in the days before windows or Windows, there were
times when you needed to overwrite part of the screen (for
example, with a confirmation message) and then be able to get
back to where you were. These commands sort of let you do that.
SAVE SCREEN let you make a copy of the screen image, either in a
special buffer or in a variable. RESTORE SCREEN let you put the
image back. The key word in all that is "image." The restored
screen wasn't live any more. Any @ .. GETs in it didn't work when
it was restored.Nothing's changed. SAVE SCREEN still saves an
image, though it can work on a window rather than the background
screen. RESTORE SCREEN still doesn't make things live. However,
it's easy to fool yourself into thinking these commands are
smarter than they are. When you CLEAR a Visual FoxPro form, the
controls are still there, alive, even if you can't see them. If
you SAVE SCREEN a form, then CLEAR the form, then RESTORE SCREEN,
it looks as though live controls have been restored. In fact, all
that was restored was the image. The controls were live all
along.A word of caution: SAVE SCREEN TO creates a variable type
unique unto itself—the type "S" variable. This one has some funny
behaviors not seen elsewhere. An S variable cannot be passed to a
routine as a parameter. While S variables in FoxPro/DOS stored
two bytes per row/column cell (one for the character, one for the
color), in Windows these files seem to grow enormously as they,
we suspect, inefficiently store all the color characteristics for
each pixel. This means that not only are the variables and files
ridiculously large, they are also incompatible between
platforms.These are legacy commands. Avoid them in new code.
Toggle Visible properties to make things go away and use Refresh
methods to make objects redraw themselves. Stay away from this
stuff.
Example
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SAVE SCREEN TO sBackDrop
CLEAR
* Now display something else
CLEAR
RESTORE SCREEN FROM sBackDrop
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Copyright © 2002-2018 by Tamar E. Granor,
Ted Roche, Doug Hennig, and Della Martin. Click for license
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