1. large bitmap
- Posted by tone.skoda at siol.net
Feb 05, 2002
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First, how can I read only a part of bitmap? Let's say I have a very large
bitmap, 100MB, and I want to only read one rectangle out of it.
This is Windows bitmap (I am a little confused what types of bitmaps are there,
DIB?, ...)
Second, I want to display that large bitmap zoomed out. I was thinking I would
only read every third byte from file, or whatever zoom there is, so that loading
would be much faster, especially if bitmap would be very zoomed out.
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<DIV><FONT face=Arial size=2>First, how can I read only a part of bitmap? Let's
say I have a very large bitmap, 100MB, and I want to only read one rectangle out
of it.<BR>This is Windows bitmap (I am a little confused what types of bitmaps
are there, DIB?, ...)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Second, I want to display that large bitmap zoomed
out. I was thinking I would only read every third byte from file, or whatever
zoom there is, so that loading would be much faster, especially if bitmap would
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2. Re: large bitmap
- Posted by tone.skoda at siol.net
Feb 06, 2002
There is some cool stuff but not what i need this moment
I want to read from file only data needed, so that loading will still be
fast.
There is a bug: You need to change
integer DIBDC, DIB
to
atom DIBDC, DIB
and in dibdraw.ew
this:
integer currentdc -- hold dc value to be more compatible for win32lib users
to this:
atom currentdc -- hold dc value to be more compatible for win32lib users
else it fails on Windows 2000, it says: type check failure for DIB (and
currentdc) but only sometimes
----- Original Message -----
From: "Mike" <vulcan at win.co.nz>
To: "EUforum" <EUforum at topica.com>
Sent: Wednesday, February 06, 2002 12:09 AM
Subject: RE: large bitmap
>
> Tone, I have just now sent an update of my dib library to RDS. The only
> adjustments made in this release were adding 2 new demos. These demos
> show zooming and displaying only part of a bitmap (in this case a dib).
> If your computer has enough memory (ram) then this will not be a problem
> but to load 100mb might take some time..
>
> Mike
>
>
> tone.skoda at siol.net wrote:
> > First, how can I read only a part of bitmap? Let's say I have a very
> > large bitmap, 100MB, and I want to only read one rectangle out of it.
> > This is Windows bitmap (I am a little confused what types of bitmaps are
> > there, DIB?, ...)
> >
> > Second, I want to display that large bitmap zoomed out. I was thinking I
> > would only read every third byte from file, or whatever zoom there is,
> > so that loading would be much faster, especially if bitmap would be very
> > zoomed out.
>
>
>
>
