dnl Test for libpng
AC_DEFUN([AM_PATH_LIBPNG],
[
if test x$with_libpng != xno && test -z "$LIBPNG"; then
AC_MSG_CHECKING(for libpng12)
if pkg-config --exists libpng12 ; then
AC_MSG_RESULT(yes)
PNG='png'
PNG_DEP_CFLAGS_PACKAGES=libpng12
LIBPNG=`pkg-config --libs libpng12`
else
AC_MSG_RESULT(no)
AC_CHECK_LIB(png, png_read_info,
[AC_CHECK_HEADER(png.h,
png_ok=yes,
png_ok=no)],
AC_MSG_WARN(*** PNG library not found), -lz -lm)
if test "$png_ok" = yes; then
AC_MSG_CHECKING([for png_structp in png.h])
AC_TRY_COMPILE([#include <png.h>],
[png_structp pp; png_infop info; png_colorp cmap; png_create_read_struct;],
png_ok=yes,
png_ok=no)
AC_MSG_RESULT($png_ok)
if test "$png_ok" = yes; then
PNG='png'; LIBPNG='-lpng -lz'
else
AC_MSG_WARN(*** PNG library is too old)
fi
else
AC_MSG_WARN(*** PNG header file not found)
fi
fi
fi
if test x$with_libpng != xno && test -z "$LIBPNG"; then
AC_MSG_ERROR([
*** Checks for PNG library failed. You can build the library without it by
*** passing --without-tools to configure but utility tools are not to be
*** built.])
fi
AC_SUBST(LIBPNG)
])
