This is the mail archive of the cygwin@cygwin.com mailing list for the Cygwin project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: jpeg package: wrong jpeglib.h?


Teun Burgers wrote:

I've got a program that won't compile with /usr/include/jpeglib.h.
The reason is that struct jpeg_component_info does
not contain height_in_blocks.

The jpeglib.h distributed in jpegsrc.v6b.tar.gz from
http://www.ijg.org/files/ *does* contains height_in_blocks.

What is the reason for using a different jpeglib.h?

Cygwin's jpeg is built with the lossless jpeg patch, which modifies the header files slightly. However, if you read the header file carefully, height_in_blocks is in the PRIVATE section of the header. It is NOT supposed to be accessed by external programs -- I have this on the highest (for jpeg) authority, Tom Lane himself.


So, don't do that.

But, if you must do that, height_in_blocks has simply been renamed to "height_in_data_units" -- because with lossless jpeg, each "compression unit" is not necessarily a DCT block.

Please search the mailing list archives where this has been discussed in the past. IIRC several mechanisms for working transparently with the cygwin versions of the jpeglib headers were presented in those discussions.

--
Chuck



--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]