Review: libtiff 4.0 support

Changes to compile cleanly and work correctly with the libtiff 4.0 beta.

[Chris Foster, 2011-01-08 04:49:54]

From a brief skim through the code, I gather that the jpeg EXIF data is embedded
as a standard TIFF directory, but other than that your code in jpegexif.cpp has
nothing to do with libtiff?

If that's correct,  it strikes me that a cleaner way to address this issue is to
always define our own TIFF-related structs and remove any dependence on libtiff
completely, even when using the earlier versions.  It might also be nice to have
a brief comment somewhere describing that this is what we're doing (if indeed it
is!)

http://codereview.appspot.com/3854041/diff/1/src/jpeg.imageio/jpegexif.cpp
File src/jpeg.imageio/jpegexif.cpp (right):

http://codereview.appspot.com/3854041/diff/1/src/jpeg.imageio/jpegexif.cpp#ne...
src/jpeg.imageio/jpegexif.cpp:56: };
libtiff uses their own precisely sized integer types (uint16 etc) to define the
fields here.  My preference would be that we do the same using uint16_t etc. 
(handily included in boost/cstdint.hpp)

[larrygritz, 2011-01-09 05:55:15]

On 2011/01/08 04:49:54, Chris Foster wrote:
> From a brief skim through the code, I gather that the jpeg EXIF data is
embedded
> as a standard TIFF directory, but other than that your code in jpegexif.cpp
has
> nothing to do with libtiff?

No, unfortunately, there are other things that this file needs from tiff.h,
include the enum TIFFDataType and the tag numbers of all the individual Exif
tags. To cut tiff.h out entirely, we'd have to replicate even more that's in
there.


>
http://codereview.appspot.com/3854041/diff/1/src/jpeg.imageio/jpegexif.cpp#ne...
> src/jpeg.imageio/jpegexif.cpp:56: };
> libtiff uses their own precisely sized integer types (uint16 etc) to define
the
> fields here.  My preference would be that we do the same using uint16_t etc. 
> (handily included in boost/cstdint.hpp)

Fair enough.

[Chris Foster, 2011-01-09 07:15:59]

On Sun, Jan 9, 2011 at 3:55 PM,  <larrygritz@gmail.com> wrote:
> On 2011/01/08 04:49:54, Chris Foster wrote:
>>
>>  From a brief skim through the code, I gather that the jpeg EXIF data
>
> is embedded
>>
>> as a standard TIFF directory, but other than that your code in
>
> jpegexif.cpp has
>>
>> nothing to do with libtiff?
>
> No, unfortunately, there are other things that this file needs from
> tiff.h, include the enum TIFFDataType and the tag numbers of all the
> individual Exif tags. To cut tiff.h out entirely, we'd have to replicate
> even more that's in there.

Oops, I missed that huge table of tags somehow!  Ok then maybe cutting out
libtiff isn't such a good idea :)