I was assuming that the bitmaps you were talking
about were pictures or icons, not a screen capture.
You are correct that capturing a bitmap at various
points just to have onhand when an update request
comes is a pretty nasty thing to have to do ... but you
don't have to do it that way.
Generally for refresh purposes it is best to have all
the -data- required to reproduce the display available
and just redraw the display from the data when the
update request comes through. (For icons, the data
would be a bitmap, for fields the data would be text, etc).
If you always have all the -data- available, you can always
recreate the screen.
--
-Richard M. Hartman
[EMAIL PROTECTED]
186,000 mi/sec: not just a good idea, it's the LAW!
Mike Davis wrote in message <13688@palm-dev-forum>...
> To answer your question: you don't.
>
> To ask one (or two) of my own: What is this about having to save it at
> any point which might cause a popup? Why would you need to save the
> bitmap more than once?
The popups are caused, potentially, at any instruction step, in a
user program, that is executed. Any step has the potential to cause
a popup. So, potentially, after any instruction, I might have to
perform a frmUpdate. Reality is that in a program there might be
only two or three popups, but having to anticipate the popups would
mean saving the state at each instruction. That is a terrible speed
penalty.
Well, now that I think about it, the bitmap does not have to be saved
more than once. I was thinking of the bitmap of the entire screen
which would have also had things written to it. I have multi-colored
keys, on a calculator. To do that, I had to write the button labels
at text with WinDrawChars. So, I was thinking that I needed to save
the entire bitmap. But I guess I could just save the individual
bitmaps once and restore the state (redraw, if necessary) but still
means saving the entire state after each instruction.
FrmDrawForm is the easiest to refresh the entire screen. It works
great except that the display blinks. If I remove FrmDrawForm and
use FldDrawField, and CtlDrawControl everything works ok but that's a
lot of individual refreshing. Then I still have to deal with the
bitmaps. It would be so much easier if FrmDrawForm could just redraw
without erasing. Maybe I'm missing something.
> --
> -Richard M. Hartman
> [EMAIL PROTECTED]
>
> 186,000 mi/sec: not just a good idea, it's the LAW!
>
>
> Mike Davis wrote in message <13552@palm-dev-forum>...
>
> ...
>
> The other problem is that the app has bitmaps. Someone suggested
> saving and redrawing the bitmaps but doing that would require saving
> the bitmap at any point which might cause a popup (which can be
> anywhere) and would really slow down operation. The bitmap must
> already be saved somewhere because FrmDrawForm refreshes it ok. So
> there must be a way to refresh (redraw) a bitmap without having to
> save it as an independent step.
>
> How does one refresh a bitmap without having to save it first?
>
>
>
>
> --
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