Viewport, BitBlt and PictureBox.Bug ?? 
Author Message
 Viewport, BitBlt and PictureBox.Bug ??

I have a viewport (a picturebox in a picturebox).
On it I BitBlt icons.
I gradually extend the inner picturebox height by 600 twips.
When the inner picturebox.height extends 15000 twips the extended area gets
black.
 When the inner picturebox.height extends 18000 twips the extended area gets
back to normal.
When scrolling the viewport the icons on the first 15000 twips gets blanked
out.
The icons fromn about midway in the black area up to the end (250000 twips)
stays.

Is this a PictureBox.Bug?
Or ???



Mon, 16 Sep 2002 03:00:00 GMT  
 Viewport, BitBlt and PictureBox.Bug ??
Autoredraw =Ttrue
Scalemode = 3 (vbPixel)
When height is between 15000 and 18400 the background gets black,
below and above it is ok
The graphics stays when scrolling if I have stepped  through the code.
The graphics below 17800 gets blanked out if I don't step through the code.

Clues? Ideas?.


Quote:
> > I have a viewport (a picturebox in a picturebox).
> > On it I BitBlt icons.
> > I gradually extend the inner picturebox height by 600 twips.
> > When the inner picturebox.height extends 15000 twips the extended area
> gets
> > black.
> >  When the inner picturebox.height extends 18000 twips the extended area
> gets
> > back to normal.
> > When scrolling the viewport the icons on the first 15000 twips gets
> blanked
> > out.
> > The icons fromn about midway in the black area up to the end (250000
> twips)
> > stays.

> > Is this a PictureBox.Bug?
> > Or ???

> Not sure exactly on this one, but make sure your inner picture box's
> autoredraw value is set to true and it's scalemode is pixels (3 /
vbPixels)
> Hope this helps,

>     Mike



Tue, 17 Sep 2002 03:00:00 GMT  
 Viewport, BitBlt and PictureBox.Bug ??

Quote:
> Autoredraw =Ttrue
> Scalemode = 3 (vbPixel)
> When height is between 15000 and 18400 the background gets black,
> below and above it is ok
> The graphics stays when scrolling if I have stepped  through the code.
> The graphics below 17800 gets blanked out if I don't step through the
code.

> Clues? Ideas?.

I've experienced problems also when using large picture boxes with
autoredraw set to true, is there any particular reason that it has to be
that large?
It could simply be a problem with the picture box as I've noticed the same
thing when stretch-blitting to a picture box larger than my screen display
area.  Does your application really need the picture box to be that size or
could it work with using a smaller area?
It depends how many icons you are talking about, but as the dimensions of an
icon are typically only 32*32 pixels so you really need such a large picture
box?
Hope this helps,

    Mike



Tue, 17 Sep 2002 03:00:00 GMT  
 Viewport, BitBlt and PictureBox.Bug ??

Quote:
> The mentioned behaviour does not occur on a NT4 machine, just Windows
2000.

> Is there a change of the API between the OS:s?

I'm not sure, but I tend to find that NT handles graphical routines far
better and faster than Win9x does.  I'd have expected it to have worked in
2000 though as it's really build on the NT OS.

    Mike



Mon, 23 Sep 2002 03:00:00 GMT  
 Viewport, BitBlt and PictureBox.Bug ??
The mentioned behaviour does not occur on a NT4 machine, just Windows 2000.

Is there a change of the API between the OS:s?


Quote:
> > Autoredraw =Ttrue
> > Scalemode = 3 (vbPixel)
> > When height is between 15000 and 18400 the background gets black,
> > below and above it is ok
> > The graphics stays when scrolling if I have stepped  through the code.
> > The graphics below 17800 gets blanked out if I don't step through the
> code.

> > Clues? Ideas?.

> I've experienced problems also when using large picture boxes with
> autoredraw set to true, is there any particular reason that it has to be
> that large?
> It could simply be a problem with the picture box as I've noticed the same
> thing when stretch-blitting to a picture box larger than my screen display
> area.  Does your application really need the picture box to be that size
or
> could it work with using a smaller area?
> It depends how many icons you are talking about, but as the dimensions of
an
> icon are typically only 32*32 pixels so you really need such a large
picture
> box?
> Hope this helps,

>     Mike



Tue, 24 Sep 2002 03:00:00 GMT  
 Viewport, BitBlt and PictureBox.Bug ??
Uh, Win2K is not exactly built on Win NT ... it's a ton of new code, and
there is a major integration of Win 9X with Win NT.   I expect that there
will be a lot of "gotcha" moments in the upcoming months, and following each
of the first few service packs.

The company I work for does real-time control systems for engineering labs
and industrial applications; everything we do is based on Win NT 4.0, SP 3
or later.  Our current Win 2K plan is to start evaluation with the 2nd
service pack ...

Best Regards, Peter


Quote:
> > The mentioned behaviour does not occur on a NT4 machine, just Windows
> 2000.

> > Is there a change of the API between the OS:s?

> I'm not sure, but I tend to find that NT handles graphical routines far
> better and faster than Win9x does.  I'd have expected it to have worked in
> 2000 though as it's really build on the NT OS.

>     Mike



Tue, 24 Sep 2002 03:00:00 GMT  
 Viewport, BitBlt and PictureBox.Bug ??

Quote:
> Uh, Win2K is not exactly built on Win NT ... it's a ton of new code, and
> there is a major integration of Win 9X with Win NT.   I expect that there
> will be a lot of "gotcha" moments in the upcoming months, and following
each
> of the first few service packs.

> The company I work for does real-time control systems for engineering labs
> and industrial applications; everything we do is based on Win NT 4.0, SP 3
> or later.  Our current Win 2K plan is to start evaluation with the 2nd
> service pack ...

> Best Regards, Peter

Sorry, I guess I was mislead by the startup screen which says "Built on NT
technology" or something.
Which btw is a bit strange anyway because NT = "New Technology" so it's
effectively saying Build on New technology technology... hmm, just a
thought...

    Mike



Wed, 25 Sep 2002 03:00:00 GMT  
 
 [ 7 post ] 

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