Import of release 0.9

63 files changed, 576 insertions, 148 deletions

diff --git a/COPYING b/COPYING
index d60c31a..3912109 100644
--- a/COPYING
+++ b/COPYING
@@ -2,7 +2,7 @@
 		       Version 2, June 1991
 
  Copyright (C) 1989, 1991 Free Software Foundation, Inc.
-     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+                       51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
@@ -305,7 +305,7 @@ the "copyright" line and a pointer to where the full notice is found.
 
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 
 Also add information on how to contact you by electronic and paper mail.
@@ -313,7 +313,7 @@ Also add information on how to contact you by electronic and paper mail.
 If the program is interactive, make it output a short notice like this
 when it starts in an interactive mode:
 
-    Gnomovision version 69, Copyright (C) year  name of author
+    Gnomovision version 69, Copyright (C) year name of author
     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.
diff --git a/ChangeLog b/ChangeLog
index af8058b..1fe89f1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,36 @@
+2006-02-12  Henning Makholm  <henning@makholm.net>
+
+	* Version 0.9
+	* Add layer mode Color. Now all of the Gimp's layer modes are
+	  supported. :-)
+	* Revamp the test suite inputs once again (they did not cover all
+	  combinations of colored pixels vs fully white or blacK).
+	
+	* Version 0.8.1
+	* Add layer modes Hue, Value, Saturation and tests for same.
+
+2006-02-11  Henning Makholm  <henning@makholm.net>
+
+	* Version 0.8
+	* Add tests of various error diagnostics to the test suite
+	* Revamp some of the test suite inputs such that HSV space
+	  layer modes can be tested with the same files.
+
+	* Version 0.7.2
+	* Do not precompute the big multiplication table by default,
+	  it is quick enough to do it at run-time as needed (which
+	  lets the binaries shrink significantly).
+
+2006-02-07  Henning Makholm  <henning@makholm.net>
+
+	* Respect -A option when generating indexed PNG (that is,
+	  create a tRNS chunk even if it's trivial); add test of
+	  -A in xcf2png to the test suite.
+
 2006-01-29  Henning Makholm  <henning@makholm.net>
 
+	* Update FSF address in GPL blurbs
+
 	* Version 0.7.1
 	* A few cosmetic changes done during debianization
 	* The code now passes the testsuite on several Debian
diff --git a/Makefile.in b/Makefile.in
index 6dc0cef..0967124 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -12,12 +12,10 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 all:
 
-@SET_MAKE@
-
 srcdir			= @srcdir@
 prefix			= @prefix@
 exec_prefix		= @exec_prefix@
@@ -30,7 +28,7 @@ APPNAME			= @PACKAGE_TARNAME@
 program_transform_name	= @program_transform_name@
 
 CFLAGS			= @CFLAGS@
-LDFLAGS			= @LDFLAGS@
+LDFLAGS			= @LDFLAGS@ @LIBICONV@
 LIBS			= @LIBS@
 
 INSTALL			= @INSTALL@
@@ -44,6 +42,12 @@ PERL			= @PERL@
 o			= @OBJEXT@
 e			= @EXEEXT@
 
+# Allow using Makefile.in directly for cleaning and distmaking purposes
+ifneq (,$(findstring @,$o))
+e 			=
+srcdir			= .
+endif
+
 #############################################################################
 
 FILEIO			= io-unix
@@ -60,11 +64,11 @@ xcfinfo$e: xcfinfo.$o $(FILEIO).$o enums.$o xcf-general.$o utils.$o
 	$(CC) $(LDFLAGS) $(LIBS) $^ -o $@
 
 xcf2pnm$e: xcf2pnm.$o $(FILEIO).$o enums.$o xcf-general.$o utils.$o \
-	   pixels.$o flatten.$o flatspec.$o table.$o 
+	   pixels.$o flatten.$o flatspec.$o scaletab.$o table.$o 
 	$(CC) $(LDFLAGS) $(LIBS) $^ -o $@
 
 xcf2png$e: xcf2png.$o $(FILEIO).$o enums.$o xcf-general.$o utils.$o \
-	   pixels.$o flatten.$o flatspec.$o table.$o palette.$o
+	   pixels.$o flatten.$o flatspec.$o scaletab.$o table.$o palette.$o
 	$(CC) $(LDFLAGS) $(LIBS) -lpng $^ -o $@
 
 testscale$e: testscale.$o
@@ -87,7 +91,7 @@ enums.h: mkenumsh.pl $(ENUMSOURCES)
 	$(PERL) $< $(ENUMSOURCES) > $@
 enums.c: mkenumsc.pl enums.h
 	$(PERL) $< enums.h > $@
-table.c: mktablec.pl
+table.c: mktablec.pl config.h
 	$(PERL) $< > $@
 
 %.oi: options.i mkopti.pl config.h
@@ -103,6 +107,7 @@ table.c: mktablec.pl
 COMMON_HEADERS = xcftools.h config.h enums.h
 enums.$o:	enums.h
 table.$o:	$(COMMON_HEADERS) pixels.h
+scaletab.$o:	$(COMMON_HEADERS) pixels.h
 io-unix.$o:     $(COMMON_HEADERS)
 xcf-general.$o: $(COMMON_HEADERS)
 utils.$o:	$(COMMON_HEADERS)
@@ -141,6 +146,7 @@ realclean: distclean
 #
 #  Tarball-making rule
 
+ifeq (,$(findstring @,$o))
 dist: ajour distclean
 	noncvs > notcvsfiles || cp dist-generated notcvsfiles
 	diff -u dist-generated notcvsfiles
@@ -148,35 +154,44 @@ dist: ajour distclean
 	find . -type f -print | grep -v CVS | grep -v debian | \
 		sed 's!^\./!$(APPNAME)-$(VERSION)/!' | sort -o tar-manifest
 	ln -s . $(APPNAME)-$(VERSION)
-	tar cvzf $(APPNAME)-$(VERSION).tar.gz `cat tar-manifest`
+	GZIP=-9 tar cvzf $(APPNAME)-$(VERSION).tar.gz `cat tar-manifest`
 	rm tar-manifest
 	rm $(APPNAME)-$(VERSION)
+else
+dist: ajour
+	$(MAKE) dist
+endif
+
 
 #############################################################################
 #
 #  Autofoo rules:
 
-aclocal.m4: configure.ac
+aclocal.m4$(SUPPRESS_AUTOFOO): configure.ac
 	aclocal
 
-$(srcdir)/configure: configure.ac aclocal.m4
+$(srcdir)/configure$(SUPPRESS_AUTOFOO): configure.ac aclocal.m4
 	cd $(srcdir) && autoconf
 
-$(srcdir)/config.hin: configure.ac aclocal.m4
+$(srcdir)/config.hin$(SUPPRESS_AUTOFOO): configure.ac aclocal.m4
 	cd $(srcdir) && autoheader
 	touch $@
 
-config.status: $(srcdir)/configure
-	./config.status --recheck
+config.status: $(srcdir)/configure config.sub config.guess
+	if [ -f config.status ] ; \
+	then ./config.status --recheck ; \
+	else ./configure ; fi
 
-Makefile: Makefile.in config.status
+Makefile$(SUPPRESS_AUTOFOO): Makefile.in config.status
 	./config.status $@
 
 config.h: config.hin config.status
 	./config.status $@
 	touch $@
 
-ajour: Makefile config.h config.sub config.guess
+ajour: Makefile config.h
 
 config.sub config.guess:
-	-test -r /usr/share/misc/$@ && cp /usr/share/misc/$@ .
\ No newline at end of file
+	-test -r /usr/share/misc/$@ && cp /usr/share/misc/$@ .
+
+.PHONY: ajour dist
diff --git a/README b/README
index 5990bf2..292a7ea 100644
--- a/README
+++ b/README
@@ -49,6 +49,13 @@ should compile the tools and install them in /usr/local.
 The 'configure' script is generated by GNU autoconf, and accepts
 the arguments that such scripts commonly do.
 
+You can use
+  ./configure --enable-precomputed-scaletable
+to precompute lookup tables for pixel composing at compile time.
+Normally these tables are initialized at run time if a layer that
+needs them is detected. Precomputing them may improve performance
+by a few percent, at the cost of doubling the size of each binary.
+
 License
 =======
 
@@ -66,4 +73,4 @@ GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
diff --git a/TODO b/TODO
index bdd6a80..edc4c5d 100644
--- a/TODO
+++ b/TODO
@@ -1,8 +1,6 @@
 These are things I want to do before bumping the version
 number of Xcftools to 1.0:
 
-- Add tests of error reporting to the test suite.
-
 - Finish localization infrastucture (some work has been done
   but is not completely systematic).
 
diff --git a/config.hin b/config.hin
index 1690a7c..fcafcf1 100644
--- a/config.hin
+++ b/config.hin
@@ -72,6 +72,9 @@
 /* Define to the version of this package. */
 #undef PACKAGE_VERSION
 
+/* Define to use a precomputed multiplication table (adds 64 KB per binary) */
+#undef PRECOMPUTED_SCALETABLE
+
 /* Define to 1 if you have the ANSI C header files. */
 #undef STDC_HEADERS
 
diff --git a/configure b/configure
index 63989dd..d743794 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.59 for Xcftools 0.7.1.
+# Generated by GNU Autoconf 2.59 for Xcftools 0.9.
 #
 # Report bugs to <henning@makholm.net>.
 #
@@ -273,8 +273,8 @@ SHELL=${CONFIG_SHELL-/bin/sh}
 # Identity of this package.
 PACKAGE_NAME='Xcftools'
 PACKAGE_TARNAME='xcftools'
-PACKAGE_VERSION='0.7.1'
-PACKAGE_STRING='Xcftools 0.7.1'
+PACKAGE_VERSION='0.9'
+PACKAGE_STRING='Xcftools 0.9'
 PACKAGE_BUGREPORT='henning@makholm.net'
 
 ac_unique_file="xcfinfo.c"
@@ -315,7 +315,7 @@ ac_includes_default="\
 # include <unistd.h>
 #endif"
 
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS SET_MAKE INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT build build_cpu build_vendor build_os host host_cpu host_vendor host_os CPP EGREP LIBICONV LTLIBICONV PERL LIBOBJS LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT build build_cpu build_vendor build_os host host_cpu host_vendor host_os CPP EGREP LIBICONV LTLIBICONV PERL LIBOBJS LTLIBOBJS'
 ac_subst_files=''
 
 # Initialize some variables set by options.
@@ -784,7 +784,7 @@ 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 Xcftools 0.7.1 to adapt to many kinds of systems.
+\`configure' configures Xcftools 0.9 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -850,13 +850,16 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of Xcftools 0.7.1:";;
+     short | recursive ) echo "Configuration of Xcftools 0.9:";;
    esac
   cat <<\_ACEOF
 
 Optional Features:
   --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
+  --enable-precomputed-scaletable
+                          Use precomputed multiplication table (adds 64 KB per
+                          binary)
   --disable-rpath         do not hardcode runtime library paths
 
 Optional Packages:
@@ -974,7 +977,7 @@ fi
 test -n "$ac_init_help" && exit 0
 if $ac_init_version; then
   cat <<\_ACEOF
-Xcftools configure 0.7.1
+Xcftools configure 0.9
 generated by GNU Autoconf 2.59
 
 Copyright (C) 2003 Free Software Foundation, Inc.
@@ -992,7 +995,7 @@ cat >&5 <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by Xcftools $as_me 0.7.1, which was
+It was created by Xcftools $as_me 0.9, which was
 generated by GNU Autoconf 2.59.  Invocation command line was
 
   $ $0 $@
@@ -1331,35 +1334,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-echo "$as_me:$LINENO: checking whether ${MAKE-make} sets \$(MAKE)" >&5
-echo $ECHO_N "checking whether ${MAKE-make} sets \$(MAKE)... $ECHO_C" >&6
-set dummy ${MAKE-make}; ac_make=`echo "$2" | sed 'y,:./+-,___p_,'`
-if eval "test \"\${ac_cv_prog_make_${ac_make}_set+set}\" = set"; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  cat >conftest.make <<\_ACEOF
-all:
-	@echo 'ac_maketemp="$(MAKE)"'
-_ACEOF
-# GNU make sometimes prints "make[1]: Entering...", which would confuse us.
-eval `${MAKE-make} -f conftest.make 2>/dev/null | grep temp=`
-if test -n "$ac_maketemp"; then
-  eval ac_cv_prog_make_${ac_make}_set=yes
-else
-  eval ac_cv_prog_make_${ac_make}_set=no
-fi
-rm -f conftest.make
-fi
-if eval "test \"`echo '$ac_cv_prog_make_'${ac_make}_set`\" = yes"; then
-  echo "$as_me:$LINENO: result: yes" >&5
-echo "${ECHO_T}yes" >&6
-  SET_MAKE=
-else
-  echo "$as_me:$LINENO: result: no" >&5
-echo "${ECHO_T}no" >&6
-  SET_MAKE="MAKE=${MAKE-make}"
-fi
-
 ac_aux_dir=
 for ac_dir in $srcdir $srcdir/.. $srcdir/../..; do
   if test -f $ac_dir/install-sh; then
@@ -1478,6 +1452,16 @@ program_transform_name=`echo $program_transform_name | sed -f conftest.sed`
 rm conftest.sed
 
 
+# Check whether --enable-precomputed-scaletable or --disable-precomputed-scaletable was given.
+if test "${enable_precomputed_scaletable+set}" = set; then
+  enableval="$enable_precomputed_scaletable"
+
+cat >>confdefs.h <<\_ACEOF
+#define PRECOMPUTED_SCALETABLE 1
+_ACEOF
+
+fi;
+
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
@@ -4760,7 +4744,7 @@ fi
 
           ac_config_headers="$ac_config_headers config.h:config.hin"
 
-          ac_config_files="$ac_config_files Makefile"
+          ac_config_files="$ac_config_files Makefile:Makefile.in"
 
 cat >confcache <<\_ACEOF
 # This file is a shell script that caches the results of configure
@@ -5124,7 +5108,7 @@ _ASBOX
 } >&5
 cat >&5 <<_CSEOF
 
-This file was extended by Xcftools $as_me 0.7.1, which was
+This file was extended by Xcftools $as_me 0.9, which was
 generated by GNU Autoconf 2.59.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -5184,7 +5168,7 @@ _ACEOF
 
 cat >>$CONFIG_STATUS <<_ACEOF
 ac_cs_version="\\
-Xcftools config.status 0.7.1
+Xcftools config.status 0.9
 configured by $0, generated by GNU Autoconf 2.59,
   with options \\"`echo "$ac_configure_args" | sed 's/[\\""\`\$]/\\\\&/g'`\\"
 
@@ -5287,7 +5271,7 @@ for ac_config_target in $ac_config_targets
 do
   case "$ac_config_target" in
   # Handling of arguments.
-  "Makefile" ) CONFIG_FILES="$CONFIG_FILES Makefile" ;;
+  "Makefile" ) CONFIG_FILES="$CONFIG_FILES Makefile:Makefile.in" ;;
   "config.h" ) CONFIG_HEADERS="$CONFIG_HEADERS config.h:config.hin" ;;
   *) { { echo "$as_me:$LINENO: error: invalid argument: $ac_config_target" >&5
 echo "$as_me: error: invalid argument: $ac_config_target" >&2;}
@@ -5373,7 +5357,6 @@ s,@ECHO_C@,$ECHO_C,;t t
 s,@ECHO_N@,$ECHO_N,;t t
 s,@ECHO_T@,$ECHO_T,;t t
 s,@LIBS@,$LIBS,;t t
-s,@SET_MAKE@,$SET_MAKE,;t t
 s,@INSTALL_PROGRAM@,$INSTALL_PROGRAM,;t t
 s,@INSTALL_SCRIPT@,$INSTALL_SCRIPT,;t t
 s,@INSTALL_DATA@,$INSTALL_DATA,;t t
diff --git a/configure.ac b/configure.ac
index 849a5d6..952c429 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,20 +13,26 @@ dnl GNU General Public License for more details.
 dnl
 dnl You should have received a copy of the GNU General Public License
 dnl along with this program; if not, write to the Free Software
-dnl Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+dnl Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 dnl
 dnl ------------------------
 dnl The following line is the MASTER SOURCE for the version number
-AC_INIT(Xcftools,0.7.1,henning@makholm.net,xcftools)
+AC_INIT(Xcftools,0.9,henning@makholm.net,xcftools)
 AC_COPYRIGHT(General copyright notice for AC_PACKAGE_NAME:
    [@COPYRIGHT@  Henning Makholm]
 )
 AC_CONFIG_SRCDIR(xcfinfo.c)
         
-AC_PROG_MAKE_SET
 AC_PROG_INSTALL
 AC_ARG_PROGRAM
 
+AC_ARG_ENABLE(precomputed-scaletable,
+        AC_HELP_STRING([--enable-precomputed-scaletable],
+          [Use precomputed multiplication table (adds 64 KB per binary)]),
+        [AC_DEFINE(PRECOMPUTED_SCALETABLE,1,
+   [Define to use a precomputed multiplication table (adds 64 KB per binary)]
+           )])
+
 AC_PROG_CC
 case $GCC::$CFLAGS in yes::*-Wall* ) ;;
                       yes::*) CFLAGS="$CFLAGS -Wall" ;;
@@ -46,10 +52,11 @@ AC_CHECK_HEADERS(inttypes.h netinet/in.h arpa/inet.h getopt.h)
 
 AC_CHECK_FUNCS(getopt_long strcasecmp)
 AC_FUNC_MMAP
+dnl AM_GNU_GETTEXT(external)
 AM_ICONV
 
 AC_CHECK_PROG(PERL,perl,perl)
-                
+                        
 AC_CONFIG_HEADERS(config.h:config.hin)
-AC_CONFIG_FILES(Makefile)
+AC_CONFIG_FILES(Makefile:Makefile.in)
 AC_OUTPUT
diff --git a/dist-generated b/dist-generated
index 2656aed..81650d1 100644
--- a/dist-generated
+++ b/dist-generated
@@ -1,4 +1,6 @@
 aclocal.m4
+config.guess
 config.hin
+config.sub
 configure
 notcvsfiles
diff --git a/flatspec.c b/flatspec.c
index e318458..ca2b22c 100644
--- a/flatspec.c
+++ b/flatspec.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
diff --git a/flatten.c b/flatten.c
index 9b148bb..45ce005 100644
--- a/flatten.c
+++ b/flatten.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
@@ -96,6 +96,8 @@ merge_normal(struct Tile *bot, struct Tile *top)
       break ;
   }
 
+  INIT_SCALETABLE_IF( !(top->summary & TILESUMMARY_CRISP) );
+  
   /* Otherwise bot wins, but is forever changed ... */
   if( (top->summary & TILESUMMARY_ALLNULL) == 0 ) {
     unsigned i ;
@@ -220,10 +222,39 @@ ucombine_GRAIN_MERGE(uint8_t bot,uint8_t top)
   return temp < 0 ? 0 : temp >= 256 ? 255 : temp ;
 }
 
+struct HSV {
+  enum { HUE_RED_GREEN_BLUE,HUE_RED_BLUE_GREEN,HUE_BLUE_RED_GREEN,
+         HUE_BLUE_GREEN_RED,HUE_GREEN_BLUE_RED,HUE_GREEN_RED_BLUE } hue;
+  unsigned ch1, ch2, ch3 ;
+};
 
+static void
+RGBtoHSV(rgba rgb,struct HSV *hsv)
+{
+  unsigned RED = (uint8_t)(rgb >> RED_SHIFT);
+  unsigned GREEN = (uint8_t)(rgb >> GREEN_SHIFT);
+  unsigned BLUE = (uint8_t)(rgb >> BLUE_SHIFT) ;
+  #define HEXTANT(b,m,t) hsv->ch1 = b, hsv->ch2 = m, hsv->ch3 = t, \
+                         hsv->hue = HUE_ ## b ## _ ## m ## _ ## t
+  if( GREEN <= RED )
+    if( BLUE <= RED )
+      if( GREEN <= BLUE )
+        HEXTANT(GREEN,BLUE,RED);
+      else
+        HEXTANT(BLUE,GREEN,RED);
+    else
+      HEXTANT(GREEN,RED,BLUE);
+  else if( BLUE <= RED )
+    HEXTANT(BLUE,RED,GREEN);
+  else if( BLUE <= GREEN )
+    HEXTANT(RED,BLUE,GREEN);
+  else
+    HEXTANT(RED,GREEN,BLUE);
+  #undef HEXTANT
+}
 
 /* merge_exotic() destructively updates bot.
- * merge_exotoc() reads but does not free top.
+ * merge_exotic() reads but does not free top.
  */
 static void __ATTRIBUTE__((noinline))
 merge_exotic(struct Tile *bot, const struct Tile *top,
@@ -236,16 +267,18 @@ merge_exotic(struct Tile *bot, const struct Tile *top,
   assert( bot->refcount == 1 );
   /* The transparency status of bot never changes */
 
+  INIT_SCALETABLE_IF(1);
+  
   for( i=0; i < top->count ; i++ ) {
-    uint32_t red, green, blue ;
+    uint32_t RED, GREEN, BLUE ;
     if( NULLALPHA(bot->pixels[i]) || NULLALPHA(top->pixels[i]) )
       continue ;
 #define UNIFORM(mode) case GIMP_ ## mode ## _MODE: \
-      red   = ucombine_ ## mode (bot->pixels[i]>>RED_SHIFT  ,  \
+      RED   = ucombine_ ## mode (bot->pixels[i]>>RED_SHIFT  ,  \
                                  top->pixels[i]>>RED_SHIFT  ); \
-      green = ucombine_ ## mode (bot->pixels[i]>>GREEN_SHIFT,  \
+      GREEN = ucombine_ ## mode (bot->pixels[i]>>GREEN_SHIFT,  \
                                  top->pixels[i]>>GREEN_SHIFT); \
-      blue  = ucombine_ ## mode (bot->pixels[i]>>BLUE_SHIFT ,  \
+      BLUE  = ucombine_ ## mode (bot->pixels[i]>>BLUE_SHIFT ,  \
                                  top->pixels[i]>>BLUE_SHIFT ); \
       break ;
     switch( mode ) {
@@ -267,14 +300,92 @@ merge_exotic(struct Tile *bot, const struct Tile *top,
       UNIFORM(HARDLIGHT);
       UNIFORM(GRAIN_EXTRACT);
       UNIFORM(GRAIN_MERGE);
+    case GIMP_HUE_MODE:
+    case GIMP_SATURATION_MODE:
+    case GIMP_VALUE_MODE:
+    case GIMP_COLOR_MODE:
+      {
+        static struct HSV hsvTop, hsvBot ;
+        RGBtoHSV(top->pixels[i],&hsvTop);
+        if( mode == GIMP_HUE_MODE && hsvTop.ch1 == hsvTop.ch3 )
+          continue ;
+        RGBtoHSV(bot->pixels[i],&hsvBot);
+        if( mode == GIMP_VALUE_MODE ) {
+          if( hsvBot.ch3 ) {
+            hsvBot.ch1 = (hsvBot.ch1*hsvTop.ch3 + hsvBot.ch3/2) / hsvBot.ch3;
+            hsvBot.ch2 = (hsvBot.ch2*hsvTop.ch3 + hsvBot.ch3/2) / hsvBot.ch3;
+            hsvBot.ch3 = hsvTop.ch3 ;
+          } else {
+            hsvBot.ch1 = hsvBot.ch2 = hsvBot.ch3 = hsvTop.ch3 ;
+          }
+        } else {
+          unsigned mfNum, mfDenom ;
+          if( mode == GIMP_HUE_MODE || mode == GIMP_COLOR_MODE ) {
+            mfNum   = hsvTop.ch2-hsvTop.ch1 ;
+            mfDenom = hsvTop.ch3-hsvTop.ch1 ;
+            hsvBot.hue = hsvTop.hue ;
+          } else {
+            mfNum   = hsvBot.ch2-hsvBot.ch1 ;
+            mfDenom = hsvBot.ch3-hsvBot.ch1 ;
+          }
+          if( mode == GIMP_SATURATION_MODE ) {
+            if( hsvTop.ch3 == 0 )
+              hsvBot.ch1 = hsvBot.ch3 ; /* Black has no saturation */
+            else
+              hsvBot.ch1 = (hsvTop.ch1*hsvBot.ch3 + hsvTop.ch3/2) / hsvTop.ch3;
+          } else if( mode == GIMP_COLOR_MODE ) {
+            /* GIMP_COLOR_MODE works in HSL space instead of HSV. We must
+             * transfer H and S, keeping the L = ch1+ch3 of the bottom pixel,
+             * but the S we transfer works differently from the S in HSV.
+             */
+            unsigned L = hsvTop.ch1 + hsvTop.ch3 ;
+            unsigned sNum = hsvTop.ch3 - hsvTop.ch1 ;
+            unsigned sDenom = L < 256 ? L : 510-L ;
+            if( sDenom == 0 ) sDenom = 1 ; /* sNum will be 0 */
+            L = hsvBot.ch1 + hsvBot.ch3 ;
+            if( L < 256 ) {
+              /* Ideally we want to compute L/2 * (1-sNum/sDenom)
+               * But shuffle this a bit so we can use integer arithmetic.
+               * The "-1" in the rounding prevents us from ending up with
+               * ch1 > ch3.
+               */
+              hsvBot.ch1 = (L*(sDenom-sNum)+sDenom-1)/(2*sDenom);
+              hsvBot.ch3 = L - hsvBot.ch1 ;
+            } else {
+              /* Here our goal is 255 - (510-L)/2 * (1-sNum/sDenom) */
+              hsvBot.ch3 = 255 - ((510-L)*(sDenom-sNum)+sDenom-1)/(2*sDenom);
+              hsvBot.ch1 = L - hsvBot.ch3 ;
+            }
+            assert(hsvBot.ch3 <= 255);
+            assert(hsvBot.ch3 >= hsvBot.ch1);
+          }
+          if( mfDenom == 0 )
+            hsvBot.ch2 = hsvBot.ch1 ;
+          else
+            hsvBot.ch2 = hsvBot.ch1 +
+              (mfNum*(hsvBot.ch3-hsvBot.ch1) + mfDenom/2) / mfDenom ;
+        }
+        switch( hsvBot.hue ) {
+          #define HEXTANT(b,m,t) case HUE_ ## b ## _ ## m ## _ ## t : \
+               b = hsvBot.ch1; m = hsvBot.ch2; t = hsvBot.ch3; break;
+          HEXTANT(RED,GREEN,BLUE);
+          HEXTANT(RED,BLUE,GREEN);
+          HEXTANT(BLUE,RED,GREEN);
+          HEXTANT(BLUE,GREEN,RED);
+          HEXTANT(GREEN,BLUE,RED);
+          HEXTANT(GREEN,RED,BLUE);
+          #undef HEXTANT
+          }
+        break ;
+      }
     default:
       FatalUnsupportedXCF(_("'%s' layer mode"),showGimpLayerModeEffects(mode));
     }
     if( FULLALPHA(bot->pixels[i] & top->pixels[i]) )
       bot->pixels[i] = (bot->pixels[i] & (255 << ALPHA_SHIFT)) +
-        (red << RED_SHIFT) +
-        (green << GREEN_SHIFT) +
-        (blue << BLUE_SHIFT) ;
+        (RED << RED_SHIFT) +
+        (GREEN << GREEN_SHIFT) +
+        (BLUE << BLUE_SHIFT) ;
     else {
       rgba bp = bot->pixels[i] ;
       /* In a sane world, the alpha of the top pixel would simply be
@@ -291,9 +402,9 @@ merge_exotic(struct Tile *bot, const struct Tile *top,
         tfrac = (256*pseudotop - 1) / alpha ;
       }
       bot->pixels[i] = (bp & (255 << ALPHA_SHIFT)) +
-        ((rgba)scaletable[  tfrac  ][  red                ] << RED_SHIFT  ) +
-        ((rgba)scaletable[  tfrac  ][  green              ] << GREEN_SHIFT) +
-        ((rgba)scaletable[  tfrac  ][  blue               ] << BLUE_SHIFT ) +
+        ((rgba)scaletable[  tfrac  ][  RED                ] << RED_SHIFT  ) +
+        ((rgba)scaletable[  tfrac  ][  GREEN              ] << GREEN_SHIFT) +
+        ((rgba)scaletable[  tfrac  ][  BLUE               ] << BLUE_SHIFT ) +
         ((rgba)scaletable[255^tfrac][255&(bp>>RED_SHIFT  )] << RED_SHIFT  ) +
         ((rgba)scaletable[255^tfrac][255&(bp>>GREEN_SHIFT)] << GREEN_SHIFT) +
         ((rgba)scaletable[255^tfrac][255&(bp>>BLUE_SHIFT )] << BLUE_SHIFT ) ;
@@ -461,6 +572,7 @@ addBackground(struct FlattenSpec *spec, struct Tile *tile)
   if( tileSummary(tile) & TILESUMMARY_ALLNULL ) {
     fillTile(tile,spec->default_pixel);
   } else {
+    INIT_SCALETABLE_IF( !(tile->summary & TILESUMMARY_CRISP) );
     for( i=0; i<tile->count; i++ )
       if( NULLALPHA(tile->pixels[i]) )
         tile->pixels[i] = spec->default_pixel ;
diff --git a/flatten.h b/flatten.h
index 03aa435..bee17e2 100644
--- a/flatten.h
+++ b/flatten.h
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #ifndef FLATTEN_H
diff --git a/io-unix.c b/io-unix.c
index d7c59ed..7d1d4c5 100644
--- a/io-unix.c
+++ b/io-unix.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
diff --git a/mancombine.pl b/mancombine.pl
index 3de2919..25f377e 100644
--- a/mancombine.pl
+++ b/mancombine.pl
@@ -13,7 +13,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 use strict ; use warnings ;
 
diff --git a/mkenumsc.pl b/mkenumsc.pl
index 25542ac..5ea9829 100644
--- a/mkenumsc.pl
+++ b/mkenumsc.pl
@@ -14,7 +14,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 use strict ; use warnings ;
 
diff --git a/mkenumsh.pl b/mkenumsh.pl
index 7ac52d3..ac1a8de 100644
--- a/mkenumsh.pl
+++ b/mkenumsh.pl
@@ -14,7 +14,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 use strict ; use warnings ;
 
diff --git a/mkopti.pl b/mkopti.pl
index d2f7050..bd52333 100644
--- a/mkopti.pl
+++ b/mkopti.pl
@@ -14,7 +14,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 use strict ; use warnings ;
 
diff --git a/mktablec.pl b/mktablec.pl
index 32bb0d0..6467af0 100644
--- a/mktablec.pl
+++ b/mktablec.pl
@@ -13,7 +13,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 use strict ; use warnings ;
 
@@ -35,19 +35,37 @@ sub shipsubarray (@) {
     print "\n" ;
 }
 
+my $precompute_it = 1 ;
+if( open CONFIGH, "<", "config.h" ) {
+    $precompute_it = 0 ;
+    while( <CONFIGH> ) {
+        if( /\#\s*define\s+PRECOMPUTED_SCALETABLE/ ) {
+            $precompute_it = 1 ;
+            last ;
+        }
+    }
+    close CONFIGH ;
+}
+
 print "/* Autogenerated by $0 */\n" ;
 print "#include \"pixels.h\"\n" ;
-print "const uint8_t scaletable[256][256] = {\n" ;
-for my $p ( 0..255 ) {
-    shipsubarray( map { int(($p*$_+127)/255) } ( 0 .. 255 ) );
-    # This formula has the property that
-    # scaletable[p][q] + scaletable[255-p][q] == q
-    # for all uint8_t values of p and q.
-    # This is important in order that a partially transparent
-    # pixel does not change the color of the underlying pixel
-    # unless the two pixels have different colors.
+print "#ifdef PRECOMPUTED_SCALETABLE\n" ;
+if( $precompute_it ) {
+    print "const uint8_t scaletable[256][256] = {\n" ;
+    for my $p ( 0..255 ) {
+        shipsubarray( map { int(($p*$_+127)/255) } ( 0 .. 255 ) );
+        # This formula has the property that
+        # scaletable[p][q] + scaletable[255-p][q] == q
+        # for all uint8_t values of p and q.
+        # This is important in order that a partially transparent
+        # pixel does not change the color of the underlying pixel
+        # unless the two pixels have different colors.
+    }
+    print "};\n" ;
+} else {
+    print "#error PRECOMPUTED_SCALETABLE was not defined at generation time\n";
 }
-print "};\n" ;
+print "#endif\n" ;
 
 if(0) {
 
diff --git a/options.i b/options.i
index 07949a7..8748adf 100644
--- a/options.i
+++ b/options.i
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 OPTIONGROUP(1i,General options);
@@ -345,7 +345,7 @@ OPTION(301,--percent,(n) set opacity in percent,
   int n ;
   sscanf(optarg,"%u%n",&pct,&n) ;
   if( n != strlen(optarg) || pct > 100 )
-    FatalGeneric(20,_("The argument to --pct is not a percentage"));
+    FatalGeneric(20,_("The argument to --percent is not a percentage"));
   lastlayerspec(&flatspec,"--percent")->opacity = pct * 255 / 100 ;
   break ;
 }
diff --git a/palette.c b/palette.c
index 20947cd..5a437e9 100644
--- a/palette.c
+++ b/palette.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "palette.h"
@@ -31,8 +31,8 @@
  * 0x00, 0x11, 0x22, ..., 0xDD, 0xEE, 0xFF.
  */
 
-rgba palette[MAX_PALETTE] ;
 unsigned paletteSize ;
+rgba palette[MAX_PALETTE] ;
 static int masterhash[HASH_SIZE];
 static int bucketlinks[MAX_PALETTE];
     
diff --git a/palette.h b/palette.h
index 2453440..8fa6e5d 100644
--- a/palette.h
+++ b/palette.h
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #ifndef PALETTE_H
diff --git a/pixels.c b/pixels.c
index 20e6c81..918423f 100644
--- a/pixels.c
+++ b/pixels.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #define DEBUG
@@ -438,6 +438,7 @@ applyMask(struct Tile *tile, struct Tile *mask)
   unsigned i ;
   assertTileCompatibility(tile,mask);
   assert( tile->count == mask->count );
+  INIT_SCALETABLE_IF(1);
   invalidateSummary(tile,0);
   for( i=0; i < tile->count ;i++ )
     tile->pixels[i] = NEWALPHA(tile->pixels[i],
@@ -471,9 +472,11 @@ getLayerTile(struct xcfLayer *layer,const struct rect *where)
     applyMask(data,mask);
   }
   if( layer->opacity < 255 ) {
-    const uint8_t *ourtable = scaletable[layer->opacity] ;
+    const uint8_t *ourtable ;
     int i ;
     invalidateSummary(data,~(TILESUMMARY_CRISP | TILESUMMARY_ALLFULL));
+    INIT_SCALETABLE_IF(1);
+    ourtable = scaletable[layer->opacity] ;
     for( i=0; i < data->count; i++ )
       data->pixels[i]
         = NEWALPHA(data->pixels[i],ourtable[ALPHA(data->pixels[i])]) ;
diff --git a/pixels.h b/pixels.h
index 8d8ea2e..1ee5219 100644
--- a/pixels.h
+++ b/pixels.h
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #ifndef PIXELS_H
@@ -53,7 +53,17 @@ typedef uint32_t rgba ;
 #define NULLALPHA(rgba) ((uint8_t)(rgba) == 0)
 #define NEWALPHA(rgb,a) (((rgba)(rgb) & 0xFFFFFF00) + (a))
 
+#ifdef PRECOMPUTED_SCALETABLE
 extern const uint8_t scaletable[256][256] ;
+#define INIT_SCALETABLE_IF(foo) ((void)0)
+#else
+extern uint8_t scaletable[256][256] ;
+extern int ok_scaletable ;
+void mk_scaletable(void);
+#define INIT_SCALETABLE_IF(foo) \
+             (ok_scaletable || !(foo) || (mk_scaletable(),0) )
+#endif
+
 extern const rgba graytable[256] ;
 extern rgba colormap[256] ;
 extern unsigned colormapLength ;
diff --git a/scaletab.c b/scaletab.c
new file mode 100644
index 0000000..c09867e
--- /dev/null
+++ b/scaletab.c
@@ -0,0 +1,42 @@
+/* Run-time scaletable computation for Xcftools
+ *
+ * Copyright (C) 2006  Henning Makholm
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "pixels.h"
+#ifndef PRECOMPUTED_SCALETABLE
+
+uint8_t scaletable[256][256] ;
+int ok_scaletable = 0 ;
+
+void
+mk_scaletable(void)
+{
+  unsigned p, q, r ;
+  if( ok_scaletable ) return ;
+  for( p = 0 ; p < 128 ; p++ )
+    for( q = 0 ; q <= p ; q++  ) {
+      r = (p*q+127)/255 ;
+      scaletable[p][q] = scaletable[q][p] = r ;
+      scaletable[255-p][q] = scaletable[q][255-p] = q-r ;
+      scaletable[p][255-q] = scaletable[255-q][p] = p-r ;
+      scaletable[255-p][255-q] = scaletable[255-q][255-p] = (255-q)-(p-r) ;
+    }
+  ok_scaletable = 1 ;
+}
+
+#endif
+    
diff --git a/test/answer/Addition.png b/test/answer/Addition.png
index 93024de..c974f38 100644
--- a/test/answer/Addition.png
+++ b/test/answer/Addition.png
diff --git a/test/answer/Burn.png b/test/answer/Burn.png
index b6e747e..d4e9907 100644
--- a/test/answer/Burn.png
+++ b/test/answer/Burn.png
diff --git a/test/answer/Color.png b/test/answer/Color.png
new file mode 100644
index 0000000..f419579
--- /dev/null
+++ b/test/answer/Color.png
diff --git a/test/answer/DarkenOnly.png b/test/answer/DarkenOnly.png
index 58f71dd..9248c9b 100644
--- a/test/answer/DarkenOnly.png
+++ b/test/answer/DarkenOnly.png
diff --git a/test/answer/Difference.png b/test/answer/Difference.png
index 9a1c5fb..21e9bea 100644
--- a/test/answer/Difference.png
+++ b/test/answer/Difference.png
diff --git a/test/answer/Divide.png b/test/answer/Divide.png
index a7668ec..d0be2ee 100644
--- a/test/answer/Divide.png
+++ b/test/answer/Divide.png
diff --git a/test/answer/Dodge.png b/test/answer/Dodge.png
index 05d274b..7d76847 100644
--- a/test/answer/Dodge.png
+++ b/test/answer/Dodge.png
diff --git a/test/answer/GrainExtract.png b/test/answer/GrainExtract.png
index c386af2..724bed5 100644
--- a/test/answer/GrainExtract.png
+++ b/test/answer/GrainExtract.png
diff --git a/test/answer/GrainMerge.png b/test/answer/GrainMerge.png
index 616e232..0ca919b 100644
--- a/test/answer/GrainMerge.png
+++ b/test/answer/GrainMerge.png
diff --git a/test/answer/Hardlight.png b/test/answer/Hardlight.png
index 8a4739d..27b6284 100644
--- a/test/answer/Hardlight.png
+++ b/test/answer/Hardlight.png
diff --git a/test/answer/Hue.png b/test/answer/Hue.png
new file mode 100644
index 0000000..8acb1b3
--- /dev/null
+++ b/test/answer/Hue.png
diff --git a/test/answer/LightenOnly.png b/test/answer/LightenOnly.png
index bb2200f..893fbf7 100644
--- a/test/answer/LightenOnly.png
+++ b/test/answer/LightenOnly.png
diff --git a/test/answer/Multiply.png b/test/answer/Multiply.png
index 17e43b1..083165c 100644
--- a/test/answer/Multiply.png
+++ b/test/answer/Multiply.png
diff --git a/test/answer/Overlay.png b/test/answer/Overlay.png
index 628d2b5..ce47807 100644
--- a/test/answer/Overlay.png
+++ b/test/answer/Overlay.png
diff --git a/test/answer/Saturation.png b/test/answer/Saturation.png
new file mode 100644
index 0000000..dd20b06
--- /dev/null
+++ b/test/answer/Saturation.png
diff --git a/test/answer/Screen.png b/test/answer/Screen.png
index 9335e59..438c005 100644
--- a/test/answer/Screen.png
+++ b/test/answer/Screen.png
diff --git a/test/answer/Subtract.png b/test/answer/Subtract.png
index e5f03c5..9b68cbd 100644
--- a/test/answer/Subtract.png
+++ b/test/answer/Subtract.png
diff --git a/test/answer/Value.png b/test/answer/Value.png
new file mode 100644
index 0000000..1b259ca
--- /dev/null
+++ b/test/answer/Value.png
diff --git a/test/answer/crisp1.png b/test/answer/crisp1.png
index 927308e..f0e3f1e 100644
--- a/test/answer/crisp1.png
+++ b/test/answer/crisp1.png
diff --git a/test/answer/huetest.png b/test/answer/huetest.png
new file mode 100644
index 0000000..ec38604
--- /dev/null
+++ b/test/answer/huetest.png
diff --git a/test/answer/index4.png b/test/answer/index4.png
index 3de2398..c26cbee 100644
--- a/test/answer/index4.png
+++ b/test/answer/index4.png
diff --git a/test/answer/indextest.png b/test/answer/indextest.png
index c8ff807..e3ea6a7 100644
--- a/test/answer/indextest.png
+++ b/test/answer/indextest.png
diff --git a/test/answer/modeA.png b/test/answer/modeA.png
index 597099b..244c062 100644
--- a/test/answer/modeA.png
+++ b/test/answer/modeA.png
diff --git a/test/answer/modeB.png b/test/answer/modeB.png
index d9836da..947d025 100644
--- a/test/answer/modeB.png
+++ b/test/answer/modeB.png
diff --git a/test/dotest b/test/dotest
index 0bb6115..9074270 100755
--- a/test/dotest
+++ b/test/dotest
@@ -14,7 +14,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 export LC_CTYPE=C
 export LC_MESSAGES=C
@@ -69,6 +69,16 @@ testrun() {
     fi
 }
 
+errtest() {
+    expect=$1
+    shift
+    program=${XCFTOOLS_PREFIX}$1
+    shift
+    [ -f expected:stderr ] && \
+        (sed "1s!^!$program: !" expected:stderr > expected.stderr)
+    testrun --exit $expect $program "$@"
+}
+
 testinfo() {
     testrun ${XCFTOOLS_PREFIX}xcfinfo "$@"
 }
@@ -153,13 +163,160 @@ rm -f pngtype.want
 
 S=source
 
+cp /dev/null expected.stdout
+
+#############################################################################
+#
+#  Test for discovery of error conditions.
+#
+
+echo > expected:stderr  \
+    "The --mode option must follow a layer name on the command line"
+errtest 20 xcf2pnm $S/modetest.xcf.gz --mode Addition A B
+
+echo > expected:stderr \
+    "The --percent option must follow a layer name on the command line"
+errtest 20 xcf2png $S/tiletest.xcf.gz --percent 33 Mid
+
+echo > expected:stderr \
+    "The image has no layer called 'MID'"
+errtest 22 xcf2pnm $S/tiletest.xcf.gz Background MID -o foo.pnm
+
+echo > expected:stderr \
+    "Layer 'Vert' has no layer mask to enable"
+errtest 22 xcf2pnm $S/tiletest.xcf.gz Background Vert --mask Horiz --nomask
+
+echo > expected:stderr \
+    "Grayscale output selected, but colored pixel(s) found"
+errtest 103 xcf2pnm -o o.pgm $S/tiletest.xcf.gz Background
+errtest 103 xcf2png -o o.png -g $S/tiletest.xcf.gz Background
+rm -rf o.pgm o.png
+errtest 103 xcf2pnm -o o.pgm $S/tiletest.xcf.gz Background -f
+if [ -f o.pgm ] ; then echo o.pgm exists ; failed ; fi
+errtest 103 xcf2png -o o.png -g $S/tiletest.xcf.gz Background -f
+if [ -f o.png ] ; then echo o.png exists ; failed ; fi
+
+echo > expected:stderr \
+    "Monochrome output selected, but not all pixels are black or white"
+errtest 103 xcf2pnm -o o.pbm $S/tiletest.xcf.gz Background
+errtest 103 xcf2pnm -o o.pbm $S/tiletest.xcf.gz Background \
+    'Straight loop' 'Long and low'
+rm -rf o.pbm
+errtest 103 xcf2pnm -o o.pbm $S/tiletest.xcf.gz Background -f
+if [ -f o.pbm ] ; then echo o.pbm exists ; failed ; fi
+errtest 103 xcf2pnm -o o.pbm $S/tiletest.xcf.gz Background -f \
+    'Straight loop' 'Long and low'
+if [ -f o.pbm ] ; then echo o.pbm exists ; failed ; fi
+
+cat > expected:stderr <<EOF
+The image contains features not understood by this program:
+ 'AntiErase' layer mode
+EOF
+errtest 123 xcf2pnm $S/modetest.xcf.gz A B --mode AntiErase
+
+echo > expected:stderr \
+    "Flattened image has partially transparent pixels"
+errtest 102 xcf2pnm $S/modetest.xcf.gz -G
+
+cat > expected:stderr <<EOF
+Corrupted or malformed XCF file:
+ Not an XCF file at all (magic not recognized)
+EOF
+errtest 125 xcfinfo answer/modeA.png
+
+rm expected:stderr
+cat > expected.stderr <<EOF
+Warning: XCF version 345 not supported (trying anyway...)
+${XCFTOOLS_PREFIX}xcf2png: Corrupted or truncated XCF file
+ (0x1C7 bytes): Overlong property at 82
+EOF
+errtest 125 xcf2png $S/truncated.xcf
+
+echo > expected:stderr \
+    "Transparency found, but -a option not given"
+errtest 100 xcf2pnm $S/modetest.xcf.gz -o o.pnm
+
+echo > expected:stderr \
+    "The -a option was given, but the image has no transparency"
+errtest 101 xcf2pnm $S/modetest.xcf.gz -b white -a a.pgm
+errtest 101 xcf2pnm $S/tiletest.xcf.gz -a a.pgm
+
+echo > expected:stderr \
+    "Only one XCF file per command line, please"
+errtest 20 xcfinfo $S/tiletest.xcf.gz Background 'Long and low'
+
+rm expected:stderr
+rgbfile=/usr/lib/X11/rgb.txt
+( [ -f $rgbfile ] || echo "Could not open color database file $rgbfile" ) \
+    > expected.stderr
+echo "${XCFTOOLS_PREFIX}xcf2pnm: Unknown background color 'Plaid'" \
+    >> expected.stderr
+errtest 20 xcf2pnm $S/tiletext.xcf.gz -b Plaid
+
+echo > expected:stderr \
+    "-S option must have an argument of the form wxh"
+errtest 20 xcf2pnm $S/tiletext.xcf.gz -S 10x
+errtest 20 xcf2pnm $S/tiletext.xcf.gz -S 10x20x30
+
+echo > expected:stderr \
+    "-O option must have an argument of the form x,y"
+errtest 20 xcf2pnm $S/tiletest.xcf.gz -S 10x10 -O 2x4
+
+echo > expected:stderr \
+    "Layer mode 'GammaShift' is unknown"
+errtest 20 xcf2png $S/modetest.xcf.gz B A --mode GammaShift
+
+echo > expected:stderr \
+    "The argument to --percent is not a percentage"
+errtest 20 xcf2pnm $S/tiletest.xcf.gz Background Mid --percent -3
+errtest 20 xcf2pnm $S/tiletest.xcf.gz Background Mid --percent 20.2
+errtest 20 xcf2pnm $S/tiletest.xcf.gz Background Mid --percent 101
+
+echo > expected:stderr \
+    "The argument to --opacity is not a number between 0 and 255"
+errtest 20 xcf2pnm $S/tiletest.xcf.gz Background Mid --opacity -3
+errtest 20 xcf2pnm $S/tiletest.xcf.gz Background Mid --opacity 220.2
+errtest 20 xcf2pnm $S/tiletest.xcf.gz Background Mid --opacity 256
+
+#######################################################
+#
+#   Error tests for io-unix.c
+#
+# XXX: if another I/O module is added later, these tests should
+# be conditionally enabled
+#
+
+cat <<EOF > enoent.c
+#include <errno.h>
+#include <stdio.h>
+int main(int argc,char **argv) { errno = ENOENT;
+    if( argv[1][0] == '!' ) { errno = EACCES; argv++; }
+    perror(argv[1]); return 0; }
+EOF
+cp /dev/null expected.stderr
+testrun cc enoent.c
+./a.out $S/nonexist.xcf 2> expected:stderr
+errtest 21 xcfinfo $S/nonexist.xcf
+
+rm expected:stderr
+./a.out "Cannot execute source/nonexist.xcf" 2> expected.stderr
+errtest 126 xcf2png -Z $S/nonexist.xcf $S/tiletest.xcf.gz
+
 cp /dev/null expected.stderr
+command false
+errtest $? xcf2png -Z false $S/tiletest.xcf.gz
+
+./a.out ! "Cannot execute answer/modeA.png" 2> expected.stderr
+errtest 126 xcf2pnm -Z answer/modeA.png $S/comptest.xcf.gz
+
+rm -f expected:stderr
 
 #############################################################################
 #
 #  Use all of the example XCF inputs as checks of xcfinfo
 #
 
+cp /dev/null expected.stderr
 cat <<EOF > expected.stdout
 Version 0, 256x256 Grayscale, 2 layers, compressed RLE
 + 256x256+0+0 Grayscale-alpha Normal Partially transparent
@@ -206,6 +363,13 @@ EOF
 testinfo $S/i256.xcf.gz
 testinfo $S/i255.xcf.gz
 
+cat <<EOF > expected.stdout
+Version 0, 32x40 RGB color, 2 layers, compressed RLE
++ 32x40+0+0 RGB-alpha Hue Hue
++ 32x40+0+0 RGB Normal Background
+EOF
+testinfo $S/huetest.xcf.gz
+
 cp /dev/null expected.stdout
 
 #############################################################################
@@ -231,12 +395,16 @@ testpnm o:Subtract a:modeA modetest
 testpnm o:Addition a:modeB modetest B A -f
 for mode in Multiply Screen Overlay Difference DarkenOnly \
             LightenOnly Divide Dodge Burn GrainExtract GrainMerge \
-            Hardlight
+            Hardlight Hue Saturation Value Color
 do
   testpnm o:$mode a:modeA modetest A B --mode $mode
 done
 testpnm o:Overlay a:modeA modetest AE=AE A --mode Normal B --mode Softlight
 
+# huetest.xcf.gz is an auxiliary test that makes sure that all of the
+# six hue hexants have matching implementations in RGB->HSV and HSV->RGB
+
+testpnm o:huetest huetest
 
 #############################################################################
 #
@@ -300,12 +468,16 @@ testpnm o:burmid tiletest Mid -S 27x25 -O 5,5 -b '#963'
 #   Tests of xcf2png
 #
 
-#############################################################################
 #
 #   Basic functionality
 #
 
 testpng tiletest tiletest
+cat <<EOF > pngtype.want
+64x64x8
+color+alpha
+z0 f0 i0
+EOF
 testpng modeA modetest A
 
 #############################################################################
@@ -364,11 +536,29 @@ testpng        gray tiletest Background 'Straight loop' 'Long and low' -f
 testpng gray tiletest Background 'Straight loop' 'Long and low' -g
 testpng comptest comptest
 
-# RGB: many of the layer mode tests test this
+# RGB: The tiletest runs above test this
 
 # gray+alpha
 testpng comptestB comptest 'Partially transparent' -f
 
+# RGB+artificial alpha
+cat <<EOF > pngtype.want
+161x161x8
+color+alpha
+z0 f0 i0
+EOF
+testpng A:-pgm tiletest tiletest -A
+
+# RGS+artificial alpha, compressed
+cat <<EOF > pngtype.want
+161x161x8
+color
+z0 f0 i0
+tRNS(6)
+ 00 06 00 06 00 06
+EOF
+testpng tiletest tiletest -A -f
+
 # RGB+alpha
 cat <<EOF > pngtype.want
 16x20x8
@@ -396,7 +586,7 @@ testpng "b:0,0,0" crisp1 modetest -S16x20 -O48,46 -c -f
 testpng crisp1 modetest -S16x20 -O48,46 -f
 
 # index, various transparent colors
-testpng modeB modetest B -f
+testpng modeA modetest A -f
 
 #############################################################################
 #
@@ -445,6 +635,18 @@ PLTE(12)
 EOF
 testpng index4 indextest Background -f
 
+# 4 colors, artificial transparency
+cat <<EOF > pngtype.want
+64x64x2
+color+index
+z0 f0 i0
+PLTE(12)
+ DC 98 85  FF 00 77  10 36 38  FF B4 23
+tRNS(4)
+ FF FF FF FF
+EOF
+testpng index4 indextest Background -f -A
+
 # 16 colors, no transparency
 testpng mid tiletest -O17,17 -S32x32 -f
 
diff --git a/test/source/huetest.xcf.gz b/test/source/huetest.xcf.gz
new file mode 100644
index 0000000..b1f24a3
--- /dev/null
+++ b/test/source/huetest.xcf.gz
diff --git a/test/source/indextest.xcf.gz b/test/source/indextest.xcf.gz
index b782acf..f8675eb 100644
--- a/test/source/indextest.xcf.gz
+++ b/test/source/indextest.xcf.gz
diff --git a/test/source/mkmodebase.c b/test/source/mkmodebase.c
index 3e5c656..376be12 100644
--- a/test/source/mkmodebase.c
+++ b/test/source/mkmodebase.c
@@ -7,17 +7,14 @@
 
 void
 makepixel(int x,int y,int *r,int *g,int *b,int *a) {
-  if( y < 3 || y >= 61 ) {
+  if( x < 3 || x >= 61 ) {
     *a = 0 ;
     return ;
   }
-  if( x < 3 || x >= 61 ||
-      y < 6 || y >= 58 ) {
-    *r=*g=*b=*a=255 ;
-    return ;
-  }
-  if( x < 6 || x >= 58 )  {
-    *a=0 ;
+  if( y < 3 || y >= 61 ||
+      x < 6 || x >= 58 ) {
+    *a = 255 ;
+    *r=*g=*b= 255*(x>=32) ;
     return ;
   }
   x -= 6 ;
@@ -39,8 +36,8 @@ makepixel(int x,int y,int *r,int *g,int *b,int *a) {
   x -= 17 ;
   if( x <= 17 ) {
     *r = (17-x)*15 ;
-    *g = 255 ;
-    *b = x*15 ;
+    *g = (17-x)*15 ;
+    *b = (x-1)*15 ;
     return ;
   }
   *r=255 ;
diff --git a/test/source/modetest.xcf.gz b/test/source/modetest.xcf.gz
index c2d7f8a..d4b37c1 100644
--- a/test/source/modetest.xcf.gz
+++ b/test/source/modetest.xcf.gz
diff --git a/test/source/truncated.xcf b/test/source/truncated.xcf
new file mode 100644
index 0000000..0229b3f
--- /dev/null
+++ b/test/source/truncated.xcf
diff --git a/utils.c b/utils.c
index d7db8a8..bde0782 100644
--- a/utils.c
+++ b/utils.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
@@ -45,7 +45,7 @@ void
 FatalGeneric(int status,const char* format,...)
 {
   va_list v; va_start(v,format);
-  fprintf(stderr,"%s: ",progname);
+  if( format ) fprintf(stderr,"%s: ",progname);
   vFatalGeneric(status,format,v);
 }
 
@@ -71,7 +71,7 @@ xcfCheckspace(uint32_t addr,int spaceafter,const char *format,...)
   if( xcf_length < spaceafter || addr > xcf_length - spaceafter ) {
     va_list v; va_start(v,format);
     fprintf(stderr,"%s: %s\n ",progname,_("Corrupted or truncated XCF file"));
-    fprintf(stderr,"(%" PRIXPTR " bytes): ",(uintptr_t)xcf_length);
+    fprintf(stderr,"(0x%" PRIXPTR " bytes): ",(uintptr_t)xcf_length);
     vFatalGeneric(125,format,v) ;
   }
 }
diff --git a/xcf-general.c b/xcf-general.c
index c1d7da9..ef03de3 100644
--- a/xcf-general.c
+++ b/xcf-general.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
diff --git a/xcf2png.10 b/xcf2png.10
index b82d8e4..884a910 100644
--- a/xcf2png.10
+++ b/xcf2png.10
@@ -12,8 +12,8 @@
 \."
 \." You should have received a copy of the GNU General Public License
 \." along with this program; if not, write to the Free Software
-\." Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-.TH xcf2png 1 2006-01-25 "Xcftools" ""
+\." Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+.TH xcf2png 1 2006-02-12 "Xcftools" ""
 .SH NAME
 xcf2png \- convert from GIMP xcf files to png format
 .SH SYNOPSIS
@@ -110,8 +110,10 @@ pixels were found.
 123
 The XCF file contains presumably valid features that
 .B xcftools
-does not support. (Certain layer modes, for example, cause
-this return).
+does not support.
+(As of this writing there is no known way of getting the Gimp to produce
+an XCF file that will provoke this return. Please notify the author if you
+discover one).
 .TP
 125
 The XCF file is malformed.
@@ -140,9 +142,6 @@ especially when more than two layers are involved, or in case of
 some of the more exotic layer modes.
 These differences are usually not visible to the eye.
 .P
-A few particularly exotic layer modes (which work in HSV space rather
-than RGB space) are not currently implemented.
-.P
 There are probably other bugs lurking in corner cases. If you discover
 one, please notify the author.
 
diff --git a/xcf2png.c b/xcf2png.c
index 025b148..0643d24 100644
--- a/xcf2png.c
+++ b/xcf2png.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
@@ -113,7 +113,7 @@ init_output(void)
       invert_mono = 1 ;
     } else {
       unsigned i ;
-      int need_trans = 0 ;
+      int need_trans = flatspec.default_pixel == FORCE_ALPHA_CHANNEL ;
       color_type = PNG_COLOR_TYPE_PALETTE ;
       pngpalette = xcfmalloc(paletteSize*sizeof(png_color)) ;
       ptrans = xcfmalloc(paletteSize);
diff --git a/xcf2pnm.10 b/xcf2pnm.10
index 311bef8..28f604b 100644
--- a/xcf2pnm.10
+++ b/xcf2pnm.10
@@ -12,8 +12,8 @@
 \."
 \." You should have received a copy of the GNU General Public License
 \." along with this program; if not, write to the Free Software
-\." Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-.TH xcf2pnm 1 2006-01-22 "Xcftools" ""
+\." Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+.TH xcf2pnm 1 2006-02-12 "Xcftools" ""
 .SH NAME
 xcf2pnm \- convert from GIMP xcf files to ppm/pgm/pbm format
 .SH SYNOPSIS
@@ -134,8 +134,10 @@ was given, yet colored (or gray) pixels were found.
 123
 The XCF file contains presumably valid features that
 .B xcftools
-does not support. (Certain layer modes, for example, cause
-this return).
+does not support.
+(As of this writing there is no known way of getting the Gimp to write
+an XCF file that will provoke this return. Please notify the author if you
+discover one).
 .TP
 125
 The XCF file is malformed.
@@ -179,9 +181,6 @@ especially when more than two layers are involved, or in case of
 some of the more exotic layer modes.
 These differences are usually not visible to the eye.
 .P
-A few particularly exotic layer modes (which work in HSV space rather
-than RGB space) are not currently implemented.
-.P
 There are probably other bugs lurking in corner cases. If you discover
 one, please notify the author.
 
diff --git a/xcf2pnm.c b/xcf2pnm.c
index f13c306..190f618 100644
--- a/xcf2pnm.c
+++ b/xcf2pnm.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
@@ -155,7 +155,7 @@ pgm_callback(unsigned num,rgba *pixels)
     int gray = degrayPixel(pixels[i]) ;
     if( gray == -1 )
       FatalGeneric(103,
-                   _("Grayscale output selected, but colored pixel(s) found %d=%x"),i,pixels[i] /*XXX*/);
+                   _("Grayscale output selected, but colored pixel(s) found"));
     putc( gray, outfile );
   }
   callback_common(num,pixels);
diff --git a/xcfinfo.10 b/xcfinfo.10
index f1fbaed..f98e711 100644
--- a/xcfinfo.10
+++ b/xcfinfo.10
@@ -12,8 +12,8 @@
 \."
 \." You should have received a copy of the GNU General Public License
 \." along with this program; if not, write to the Free Software
-\." Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-.TH xcfinfo 1 2006-01-22 "Xcftools" ""
+\." Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+.TH xcfinfo 1 2006-02-12 "Xcftools" ""
 .SH NAME
 xcf2pnm \- display information about GIMP xcf files
 .SH SYNOPSIS
diff --git a/xcfinfo.c b/xcfinfo.c
index af16f7e..d10bbee 100644
--- a/xcfinfo.c
+++ b/xcfinfo.c
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #include "xcftools.h"
diff --git a/xcftools.h b/xcftools.h
index 9ae1dff..1eb31cc 100644
--- a/xcftools.h
+++ b/xcftools.h
@@ -13,7 +13,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #ifndef XCFTOOLS_H