Save work on libpng PNG loader (Issue #90)

Author: michaelrsweet

CHANGES.md

@@ -1,9 +1,10 @@
 Changes in PDFio
 ================
 
-v1.?.? - YYYY-MM-DD
+v1.5.0 - YYYY-MM-DD
 -------------------
 
+- Added support for using libpng to embed PNG images in PDF output (Issue #90)
 - Updated the pdf2txt example to support font encodings.
 
 

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.71 for pdfio 1.4.1.
+# Generated by GNU Autoconf 2.71 for pdfio 1.5.0.
 #
 # Report bugs to <https://github.com/michaelrsweet/pdfio/issues>.
 #
@@ -610,8 +610,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='pdfio'
 PACKAGE_TARNAME='pdfio'
-PACKAGE_VERSION='1.4.1'
-PACKAGE_STRING='pdfio 1.4.1'
+PACKAGE_VERSION='1.5.0'
+PACKAGE_STRING='pdfio 1.5.0'
 PACKAGE_BUGREPORT='https://github.com/michaelrsweet/pdfio/issues'
 PACKAGE_URL='https://www.msweet.org/pdfio'
 
@@ -653,6 +653,7 @@ WARNINGS
 CSFLAGS
 LIBPDFIO_STATIC
 LIBPDFIO
+PKGCONFIG_LIBPNG
 PKGCONFIG_REQUIRES
 PKGCONFIG_LIBS_PRIVATE
 PKGCONFIG_LIBS
@@ -729,6 +730,7 @@ SHELL'
 ac_subst_files=''
 ac_user_opts='
 enable_option_checking
+enable_libpng
 enable_static
 enable_shared
 enable_debug
@@ -1293,7 +1295,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures pdfio 1.4.1 to adapt to many kinds of systems.
+\`configure' configures pdfio 1.5.0 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1359,14 +1361,16 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of pdfio 1.4.1:";;
+     short | recursive ) echo "Configuration of pdfio 1.5.0:";;
    esac
   cat <<\_ACEOF
 
 Optional Features:
   --disable-option-checking  ignore unrecognized --enable/--with options
   --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
+  --enable-libpng         use libpng for pdfioFileCreateImageObjFromFile,
+                          default=auto
   --disable-static        do not install static library
   --enable-shared         install shared library
   --enable-debug          turn on debugging, default=no
@@ -1456,7 +1460,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-pdfio configure 1.4.1
+pdfio configure 1.5.0
 generated by GNU Autoconf 2.71
 
 Copyright (C) 2021 Free Software Foundation, Inc.
@@ -1612,7 +1616,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by pdfio $as_me 1.4.1, which was
+It was created by pdfio $as_me 1.5.0, which was
 generated by GNU Autoconf 2.71.  Invocation command line was
 
   $ $0$ac_configure_args_raw
@@ -2368,9 +2372,9 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-PDFIO_VERSION="1.4.1"
-PDFIO_VERSION_MAJOR="`echo 1.4.1 | awk -F. '{print $1}'`"
-PDFIO_VERSION_MINOR="`echo 1.4.1 | awk -F. '{printf("%d\n",$2);}'`"
+PDFIO_VERSION="1.5.0"
+PDFIO_VERSION_MAJOR="`echo 1.5.0 | awk -F. '{print $1}'`"
+PDFIO_VERSION_MINOR="`echo 1.5.0 | awk -F. '{printf("%d\n",$2);}'`"
 
 
 
@@ -4099,6 +4103,55 @@ fi
 fi
 
 
+# Check whether --enable-libpng was given.
+if test ${enable_libpng+y}
+then :
+  enableval=$enable_libpng;
+fi
+
+
+PKGCONFIG_LIBPNG=""
+
+
+if test "x$PKGCONFIG" != x -a x$enable_libpng != xno
+then :
+
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libpng-1.6.x" >&5
+printf %s "checking for libpng-1.6.x... " >&6; }
+    if $PKGCONFIG --exists libpng16
+then :
+
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; };
+
+printf "%s\n" "#define HAVE_LIBPNG 1" >>confdefs.h
+
+	CPPFLAGS="$($PKGCONFIG --cflags libpng16) -DHAVE_LIBPNG=1 $CPPFLAGS"
+	LIBS="$($PKGCONFIG --libs libpng16) -lz $LIBS"
+	PKGCONFIG_LIBPNG="libpng >= 1.6,"
+	PKGCONFIG_LIBS_PRIVATE="$($PKGCONFIG --libs libpng16) $PKGCONFIG_LIBS_PRIVATE"
+
+else $as_nop
+
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; };
+	if test x$enable_libpng = xyes
+then :
+
+	    as_fn_error $? "libpng-dev 1.6 or later required for --enable-libpng." "$LINENO" 5
+
+fi
+
+fi
+
+elif test x$enable_libpng = xyes
+then :
+
+    as_fn_error $? "libpng-dev 1.6 or later required for --enable-libpng." "$LINENO" 5
+
+fi
+
+
 # Check whether --enable-static was given.
 if test ${enable_static+y}
 then :
@@ -4935,7 +4988,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by pdfio $as_me 1.4.1, which was
+This file was extended by pdfio $as_me 1.5.0, which was
 generated by GNU Autoconf 2.71.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -4991,7 +5044,7 @@ ac_cs_config_escaped=`printf "%s\n" "$ac_cs_config" | sed "s/^ //; s/'/'\\\\\\\\
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config='$ac_cs_config_escaped'
 ac_cs_version="\\
-pdfio config.status 1.4.1
+pdfio config.status 1.5.0
 configured by $0, generated by GNU Autoconf 2.71,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -1,7 +1,7 @@
 dnl
 dnl Configuration script for PDFio
 dnl
-dnl Copyright © 2023-2024 by Michael R Sweet
+dnl Copyright © 2023-2025 by Michael R Sweet
 dnl
 dnl Licensed under Apache License v2.0.  See the file "LICENSE" for more
 dnl information.
@@ -21,7 +21,7 @@ AC_PREREQ([2.70])
 
 
 dnl Package name and version...
-AC_INIT([pdfio], [1.4.1], [https://github.com/michaelrsweet/pdfio/issues], [pdfio], [https://www.msweet.org/pdfio])
+AC_INIT([pdfio], [1.5.0], [https://github.com/michaelrsweet/pdfio/issues], [pdfio], [https://www.msweet.org/pdfio])
 
 PDFIO_VERSION="AC_PACKAGE_VERSION"
 PDFIO_VERSION_MAJOR="`echo AC_PACKAGE_VERSION | awk -F. '{print $1}'`"
@@ -121,6 +121,32 @@ AS_IF([$PKGCONFIG --exists zlib], [
 ])
 
 
+dnl libpng...
+AC_ARG_ENABLE([libpng], AS_HELP_STRING([--enable-libpng], [use libpng for pdfioFileCreateImageObjFromFile, default=auto]))
+
+PKGCONFIG_LIBPNG=""
+AC_SUBST([PKGCONFIG_LIBPNG])
+
+AS_IF([test "x$PKGCONFIG" != x -a x$enable_libpng != xno], [
+    AC_MSG_CHECKING([for libpng-1.6.x])
+    AS_IF([$PKGCONFIG --exists libpng16], [
+	AC_MSG_RESULT([yes]);
+	AC_DEFINE([HAVE_LIBPNG], 1, [Have PNG library?])
+	CPPFLAGS="$($PKGCONFIG --cflags libpng16) -DHAVE_LIBPNG=1 $CPPFLAGS"
+	LIBS="$($PKGCONFIG --libs libpng16) -lz $LIBS"
+	PKGCONFIG_LIBPNG="libpng >= 1.6,"
+	PKGCONFIG_LIBS_PRIVATE="$($PKGCONFIG --libs libpng16) $PKGCONFIG_LIBS_PRIVATE"
+    ], [
+	AC_MSG_RESULT([no]);
+	AS_IF([test x$enable_libpng = xyes], [
+	    AC_MSG_ERROR([libpng-dev 1.6 or later required for --enable-libpng.])
+	])
+    ])
+], [test x$enable_libpng = xyes], [
+    AC_MSG_ERROR([libpng-dev 1.6 or later required for --enable-libpng.])
+])
+
+
 dnl Library target...
 AC_ARG_ENABLE([static], AS_HELP_STRING([--disable-static], [do not install static library]))
 AC_ARG_ENABLE([shared], AS_HELP_STRING([--enable-shared], [install shared library]))