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2007.03.07 17:20 "Re: load a jpeg in bitmap", by Joris Van Damme
Enzo,
Enzo Costantini wrote:
> Is anybody who can tell me what I'd make to load a JPeg in a Bitmap
> using LibJPegFelphi?
There is no such thing as a LibJpegDelphi. The version of LibJpeg that
accompanies LibTiffDelphi, is compiled specifically for this purpose. No
attempt is made to be complete in what it exports and in its IO interface
and all, other then what I needed in LibTiffDelphi. It is not intended to be
used in any other way.
There is a version of LibJpeg that accompanies your Delphi distribution.
Maybe you'll have better luck trying that one.
In addition, there are documents in the standard LibJpeg distribution that
describe its usage. One such file is called 'libjpeg.doc'. Don't let the
extension disgust you, it's a plain text file. Here you can learn how to use
it.
> I have imported the procedures
>
> procedure jpeg_stdio_src(cinfo: PRJpegDecompressStruct; InStream:
> Pointer ); cdecl; external; procedure jpeg_stdio_dest(cinfo:
> PRJpegCompressStruct; OutStream: Pointer ); cdecl; external;
>
>
> and linked two object files:
>
> {$L JpegObj\jdatasrc.obj}
> {$L JpegObj\jdatadst.obj}
It's really not that simple. Borland doesn't support using statically linked
C .obj files inside a Delphi project. (They do support the other way around,
and of course they do support dynamic linking and such.) You can make it
work, but you need a whole bag of tricks. Even the order in which you $L the
(many more) different .obj files plays its part as that influences the
linker (I get the impression the linker does one pass only through the
stuff, links in what it already knows it needs, forgets about the rest, and
if it needs any of that rest later on it reports trouble). And even if you
get that right, there's compiler magic to resolve...
Stick with the pre-compiled LibJpeg distributed with Delphi, and you'll have
none of those problems.
Best regards,
Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be/
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