info_ptr in libpng is opaque

Development matplotlib-devel
1

Greetings!

First, my personal thanks to you good folks who make
a wonderful tool like matplotlib available.

I am currently trying to build matplotlib-1.0.1 against
libpng1.5.1, and _png.cpp failed to compile. Apparently,
libpng's info_ptr is now opaque, so the code required
multiple changes of this nature:

-- _png.cpp.orig 2011-02-12 16:42:42.000000000 -0500

···

***************
*** 350,362 ****
      png_set_sig_bytes(png_ptr, 8);
      png_read_info(png_ptr, info_ptr);

! /*png_uint_32 width = info_ptr->width;*/
! /*png_uint_32 height = info_ptr->height;*/
! png_uint_32 width = png_get_image_width( png_ptr, info_ptr );
! png_uint_32 height = png_get_image_height( png_ptr, info_ptr );

! /*int bit_depth = info_ptr->bit_depth;*/
! int bit_depth = png_get_bit_depth( png_ptr, info_ptr );

      // Unpack 1, 2, and 4-bit images
      if (bit_depth < 8)
--- 350,359 ----
      png_set_sig_bytes(png_ptr, 8);
      png_read_info(png_ptr, info_ptr);

! png_uint_32 width = info_ptr->width;
! png_uint_32 height = info_ptr->height;

! int bit_depth = info_ptr->bit_depth;

      // Unpack 1, 2, and 4-bit images
      if (bit_depth < 8)
***************

Sorry to be sending problems :-).
I suspect you have probably noticed this
already, but just in case I figured I'd send
a "head's up". Thanks!

Sincerely,
Mike Albert

2

Greetings!

First, my personal thanks to you good folks who make
a wonderful tool like matplotlib available.

I am currently trying to build matplotlib-1.0.1 against
libpng1.5.1, and _png.cpp failed to compile. Apparently,
libpng's info_ptr is now opaque, so the code required
multiple changes of this nature:

Mike,

A quick check indicates that the png_get* functions are available way back in libpng 1.2.x, so I suspect we can support everything we need to with a single modern version.

Does anyone know of a reason we need to support libpng prior to 1.2.x?

Would you attach your complete diff, please?

Thanks.

Eric

···

On 02/12/2011 12:11 PM, Michael Albert wrote:

-- _png.cpp.orig 2011-02-12 16:42:42.000000000 -0500
***************
*** 350,362 ****
       png_set_sig_bytes(png_ptr, 8);
       png_read_info(png_ptr, info_ptr);

! /*png_uint_32 width = info_ptr->width;*/
! /*png_uint_32 height = info_ptr->height;*/
! png_uint_32 width = png_get_image_width( png_ptr, info_ptr );
! png_uint_32 height = png_get_image_height( png_ptr, info_ptr );

! /*int bit_depth = info_ptr->bit_depth;*/
! int bit_depth = png_get_bit_depth( png_ptr, info_ptr );

       // Unpack 1, 2, and 4-bit images
       if (bit_depth< 8)
--- 350,359 ----
       png_set_sig_bytes(png_ptr, 8);
       png_read_info(png_ptr, info_ptr);

! png_uint_32 width = info_ptr->width;
! png_uint_32 height = info_ptr->height;

! int bit_depth = info_ptr->bit_depth;

       // Unpack 1, 2, and 4-bit images
       if (bit_depth< 8)
***************

Sorry to be sending problems :-).
I suspect you have probably noticed this
already, but just in case I figured I'd send
a "head's up". Thanks!

Sincerely,
  Mike Albert

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