inkscape fails to build against libpng 1.5

Needs verification that it doesn't break building against older libpng versions (1.2, 1.4).

(notes from #inkscape talking with JonCruz)

Unfortunately it will break building against older libpng.

What we did in ImageMagick:

    ...
    #if (PNG_LIBPNG_VER < 10500)
          png_charp
            info;
    #else
          png_bytep
            info;
    #endif
    ...
                     {
                           png_set_iCCP(ping,ping_info,(const png_charp) name,0,
    #if (PNG_LIBPNG_VER < 10500)
                             (png_charp) GetStringInfoDatum(profile),
    #else
                             (png_const_bytep) GetStringInfoDatum(profile),
    #endif
                             (png_uint_32) GetStringInfoLength(profile));

Fix committed as of revision 10061.

r10061 built ok with libpng 1.2.43 and libpng 1.4.5
(tested on OS X 10.5.8 (i386) using separate MacPorts trees for the dependencies).

Seems there are some more issues with libpng 1.5, will post a patch.

Will #8 patch be merged intro trunk?

> Will #8 patch be merged intro trunk?

Needs verification that it doesn't break building against older versions of libpng, and #ifdef'ed accordingly if needed.

Builds fine with libpng-1.4.2.

Builds fine with libpng-1.2.43 (OS X 10.5.8 i386)

See also:
« Changes to Libpng from version 1.2.42 to 1.4.0 (January 4, 2010)
(…)
5. Other changes
(…)
   d. Direct access to png_ptr->jmpbuf has been deprecated since libpng
      version 1.0.6, and libpng now generates a warning about it.

      To avoid such warnings, change
        setjmp(png_ptr->jmpbuf)

      to
        setjmp(png_jmpbuf(png_ptr))
(…)»
<http://www.libpng.org/pub/png/src/libpng-1.2.x-to-1.4.x-summary.txt>

Adding my note here instead of opening a new bug:

On Gentoo Linux ~amd64, I have libpng version 1.2.46 1.4.8 1.5.5 installed in their respective slots, e.g. Google Chrome depends on libpng-1.2. Inkscape was building OK with libpng-1.4, but on 2011-09-18 when libpng-1.5 was first added to my system, Inkscape subsequently tries to build against 1.5, but fails with the following error:

  CXX helper/png-write.o
x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -I. -I.. -I/usr/include/freetype2 -fopenmp -I/usr/include/ImageMagick -I/usr/inc
lude/libwpg-0.2 -I/usr/include/libwpd-0.9 -I/usr/include/poppler -pthread -I/usr/include/poppler/glib -I/usr/include/pop
pler -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/cairo -I/usr/include/gtk-2.0 -I/usr/lib64/gtk-2.0/inc
lude -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng15 -I/usr/include/libd
rm -I/usr/include/pango-1.0 -DPOTRACE=\"potrace\" -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/inclu
de/gtk-2.0 -I/usr/lib64/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/includ
e/pango-1.0 -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng15 -I/usr/include/libdrm -I/usr/include/libxm
l2 -I/usr/include/sigc++-2.0 -I/usr/lib64/sigc++-2.0/include -I/usr/include/gtkspell-2.0 -I/usr/include/glibmm-2.4 -I/usr/lib64
/glibmm-2.4/include -I/usr/include/giomm-2.4 -I/usr/lib64/giomm-2.4/include -I/usr/include/gdkmm-2.4 -I/usr/lib64/gdkmm-2.4/inc
lude -I/usr/include/pangomm-1.4 -I/usr/lib64/pangomm-1.4/include -I/usr/include/cairomm-1.0 -I/usr/lib64/cairomm-1.0/include -I
/usr/include/gtkmm-2.4 -I/usr/lib64/gtkmm-2.4/include -I/usr/include/atkmm-1.6 -I/usr/include/gtk-unix-print-2.0 -I../cxxtest
  -I./bind/javainc -I./bind/javainc/linux -I./extension/dbus -Werror=format-security -Wall -Wformat -Wformat-security -W -D_F
ORTIFY_SOURCE=2 -Wpointer-arith -Wcast-align -Wsign-compare -Woverloaded-virtual -Wswitch -Wno-unused-parameter -march=core2
-O2 -pipe -fno-strict-aliasing -fopenmp -c -o helper/png-write.o helper/png-write.cpp
helper/png-write.cpp: In function ‘bool sp_png_write_rgba_striped(SPDocument*, const gchar*, long unsigned int, long unsigned i
nt, double, double, int (*)(const guchar**, void**, int, int, void*), void*)’:
helper/png-write.cpp:169:9: error: invalid use of incomplete type ‘struct png_struct’
/usr/include/libpng15/png.h:830:16: error: forward declaration of ‘struct png_struct’

Fixed in trunk revision #10707.

> added: backport-proposed

Related revisions in trunk:
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/10061>
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/10707>

>> added: backport-proposed

See also:
<quote>
 Would need some hacking to be buildable with libpng15
 https://bugs.launchpad.net/inkscape/+bug/721029
 (still not buildable as of 0.48.3)
</quote>
<http://fink.cvs.sourceforge.net/viewvc/fink/dists/10.7/stable/main/finkinfo/graphics/inkscape.info?annotate=1.2#l150>

Backported to 0.48.x branch, r9907.