From 470aee77f4b52ea8e6f0be65f4ee829fae76d8c7 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Fri, 6 Jan 2017 08:43:09 +0000
Subject: [PATCH 1/9] note govips

---
 README.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/README.md b/README.md
index 93bb69cd..4102e4b1 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,8 @@ binding](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/usin
 and a [command-line
 interface](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/using-cli.html).
 Bindings are available for [Ruby](https://rubygems.org/gems/ruby-vips),
+[PHP](https://github.com/jcupitt/php-vips),
+[Go](https://github.com/davidbyttow/govips),
 JavaScript and others. There is full
 [documentation](http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/index.html).
 There are several GUIs as well, see the [VIPS

From 8bbba73d73e8cdabd473160a88c20994663eb885 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Fri, 6 Jan 2017 19:37:36 +0000
Subject: [PATCH 2/9] try to fix soname.h again

now make in install-exec-hook so we are certain libvips.la has been built
---
 TODO                | 4 ----
 libvips/Makefile.am | 6 ++----
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/TODO b/TODO
index a7bd4ade..715f4c8f 100644
--- a/TODO
+++ b/TODO
@@ -1,7 +1,3 @@
-- vipsdisp-tiny makes stripes if the image is not tagged correctly
-
-  is one of the colourspace functions not reading format?
-
 - not sure about utf8 error messages on win
 
 - strange: 
diff --git a/libvips/Makefile.am b/libvips/Makefile.am
index 9f3f91fd..3823b451 100644
--- a/libvips/Makefile.am
+++ b/libvips/Makefile.am
@@ -64,13 +64,11 @@ EXTRA_DIST = \
 
 CLEANFILES = 
 
-all-local:
-	while [ ! -f libvips.la ]; do sleep 1; done; sleep 1; \ 
+install-exec-hook:
 	echo '/* This file is autogenerated, do not edit. */' > soname.h && \
 	source libvips.la && \
 	echo "#define VIPS_SONAME \"$$dlname\"" >> soname.h && \
-	( cmp -s soname.h include/vips/soname.h || \
-		cp soname.h include/vips ) && \
+	cp soname.h $(DESTDIR)$(pkgincludedir) && \
 	rm soname.h
 
 -include $(INTROSPECTION_MAKEFILE)

From c5e675f7db4c8f5a8581724742579f4878d89b74 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Tue, 10 Jan 2017 14:12:24 +0000
Subject: [PATCH 3/9] fix --vips-cache-max etc.

--vips-cache-max, --vips-cache-max-memory and --vips-cache-max-files were not
working and probably hadn't been for a while

vipsthumbnail.c turns off the operation cache, it's not useful for
the same operation repeated across many files
---
 ChangeLog                       |  1 +
 libvips/include/vips/internal.h |  5 -----
 libvips/iofuncs/cache.c         | 15 ---------------
 libvips/iofuncs/init.c          | 33 ++++++++++++++++++++++++++++++---
 libvips/resample/thumbnail.c    | 26 ++++++++++++++++++++++++++
 tools/vipsthumbnail.c           |  4 ++++
 6 files changed, 61 insertions(+), 23 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b00adb01..32a4f5c7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,6 +19,7 @@
   VIPS_LIBRARY_AGE
 - better support for bscale / bzero in fits images
 - deprecate vips_warn() / vips_info(); use g_warning() / g_info() instead
+- fix --vips-cache-max etc. 
 
 8/12/16 started 8.4.5
 - allow libgsf-1.14.26 to help centos, thanks tdiprima
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index 1fa940a1..379d0ad7 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -94,11 +94,6 @@ extern int vips__info;
  */
 extern char *vips__disc_threshold;
 
-/* Cache size settings.
- */
-extern char *vips__cache_max;
-extern char *vips__cache_max_mem;
-extern char *vips__cache_max_files;
 extern gboolean vips__cache_dump;
 extern gboolean vips__cache_trace;
 
diff --git a/libvips/iofuncs/cache.c b/libvips/iofuncs/cache.c
index c2393e2e..d5810fc3 100644
--- a/libvips/iofuncs/cache.c
+++ b/libvips/iofuncs/cache.c
@@ -67,9 +67,6 @@
 
 /* Set by GOption from the command line, eg. "12m".
  */
-char *vips__cache_max = NULL;
-char *vips__cache_max_mem = NULL;
-char *vips__cache_max_files = NULL;
 gboolean vips__cache_dump = FALSE;
 gboolean vips__cache_trace = FALSE;
 
@@ -456,18 +453,6 @@ vips__cache_init( void )
 		vips_cache_table = g_hash_table_new( 
 			(GHashFunc) vips_operation_hash, 
 			(GEqualFunc) vips_operation_equal );
-
-		if( vips__cache_max ) 
-			vips_cache_max = 
-				vips__parse_size( vips__cache_max );
-
-		if( vips__cache_max_mem ) 
-			vips_cache_max_mem = 
-				vips__parse_size( vips__cache_max_mem );
-
-		if( vips__cache_max_files ) 
-			vips_cache_max_files = 
-				vips__parse_size( vips__cache_max_files );
 	}
 }
 
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index d8bfd35f..b6c367b2 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -614,6 +614,33 @@ vips_lib_version_cb( const gchar *option_name, const gchar *value,
 	exit( 0 );
 }
 
+static gboolean
+vips_cache_max_cb( const gchar *option_name, const gchar *value, 
+	gpointer data, GError **error )
+{
+	vips_cache_set_max( vips__parse_size( value ) );
+
+	return( TRUE ); 
+}
+
+static gboolean
+vips_cache_max_memory_cb( const gchar *option_name, const gchar *value, 
+	gpointer data, GError **error )
+{
+	vips_cache_set_max_mem( vips__parse_size( value ) );
+
+	return( TRUE ); 
+}
+
+static gboolean
+vips_cache_max_files_cb( const gchar *option_name, const gchar *value, 
+	gpointer data, GError **error )
+{
+	vips_cache_set_max_files( vips__parse_size( value ) );
+
+	return( TRUE ); 
+}
+
 static GOptionEntry option_entries[] = {
 	{ "vips-info", 0, G_OPTION_FLAG_HIDDEN | G_OPTION_FLAG_NO_ARG, 
 		G_OPTION_ARG_CALLBACK, (gpointer) &vips_lib_info_cb,
@@ -652,13 +679,13 @@ static GOptionEntry option_entries[] = {
 		G_OPTION_ARG_NONE, &vips__vector_enabled, 
 		N_( "disable vectorised versions of operations" ), NULL },
 	{ "vips-cache-max", 0, 0, 
-		G_OPTION_ARG_STRING, &vips__cache_max, 
+		G_OPTION_ARG_CALLBACK, (gpointer) &vips_cache_max_cb,
 		N_( "cache at most N operations" ), "N" },
 	{ "vips-cache-max-memory", 0, 0, 
-		G_OPTION_ARG_STRING, &vips__cache_max_mem, 
+		G_OPTION_ARG_CALLBACK, (gpointer) &vips_cache_max_memory_cb,
 		N_( "cache at most N bytes in memory" ), "N" },
 	{ "vips-cache-max-files", 0, 0, 
-		G_OPTION_ARG_STRING, &vips__cache_max_files, 
+		G_OPTION_ARG_CALLBACK, (gpointer) &vips_cache_max_files_cb,
 		N_( "allow at most N open files" ), "N" },
 	{ "vips-cache-trace", 0, 0, 
 		G_OPTION_ARG_NONE, &vips__cache_trace, 
diff --git a/libvips/resample/thumbnail.c b/libvips/resample/thumbnail.c
index c90c5610..db6d18c5 100644
--- a/libvips/resample/thumbnail.c
+++ b/libvips/resample/thumbnail.c
@@ -106,6 +106,30 @@ typedef struct _VipsThumbnailClass {
 
 G_DEFINE_ABSTRACT_TYPE( VipsThumbnail, vips_thumbnail, VIPS_TYPE_OPERATION );
 
+static void
+vips_thumbnail_dispose( GObject *gobject )
+{
+#ifdef DEBUG
+	printf( "vips_thumbnail_dispose: " );
+	vips_object_print_name( VIPS_OBJECT( gobject ) );
+	printf( "\n" );
+#endif /*DEBUG*/
+
+	G_OBJECT_CLASS( vips_thumbnail_parent_class )->dispose( gobject );
+}
+
+static void
+vips_thumbnail_finalize( GObject *gobject )
+{
+#ifdef DEBUG
+	printf( "vips_thumbnail_finalize: " );
+	vips_object_print_name( VIPS_OBJECT( gobject ) );
+	printf( "\n" );
+#endif /*DEBUG*/
+
+	G_OBJECT_CLASS( vips_thumbnail_parent_class )->finalize( gobject );
+}
+
 /* Calculate the shrink factor, taking into account auto-rotate, the fit mode,
  * and so on.
  */
@@ -470,6 +494,8 @@ vips_thumbnail_class_init( VipsThumbnailClass *class )
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
 
+	gobject_class->dispose = vips_thumbnail_dispose;
+	gobject_class->finalize = vips_thumbnail_finalize;
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
 
diff --git a/tools/vipsthumbnail.c b/tools/vipsthumbnail.c
index e6a184e4..f3fa487b 100644
--- a/tools/vipsthumbnail.c
+++ b/tools/vipsthumbnail.c
@@ -265,6 +265,10 @@ main( int argc, char **argv )
 	textdomain( GETTEXT_PACKAGE );
 	setlocale( LC_ALL, "" );
 
+	/* The operation cache is not useful for processing many files.
+	vips_cache_set_max( 0 );
+	 */
+
 	/* On Windows, argv is ascii-only .. use this to get a utf-8 version of
 	 * the args.
 	 */

From d1ef5a68901df9cb71113a7c7ef411a473b20d20 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Wed, 11 Jan 2017 14:05:50 +0000
Subject: [PATCH 4/9] compiles, needs more testing

---
 TODO                            |  64 ++++++
 libvips/arithmetic/arithmetic.c |   7 +-
 libvips/convolution/conv.c      |   3 +
 libvips/include/vips/image.h    |   5 +
 libvips/include/vips/internal.h |   4 +
 libvips/iofuncs/Makefile.am     |   1 +
 libvips/iofuncs/generate.c      |   3 +
 libvips/iofuncs/init.c          |   4 +
 libvips/iofuncs/recomp.c        | 331 ++++++++++++++++++++++++++++++++
 9 files changed, 418 insertions(+), 4 deletions(-)
 create mode 100644 libvips/iofuncs/recomp.c

diff --git a/TODO b/TODO
index 715f4c8f..9af9f705 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,67 @@
+- try with our Python script
+
+- check sort is going in the right direction
+
+- use vips_image_prepare_many() elsewhere
+
+- add vips__recomp_add_margin() elsewhere
+
+- should add_margin be in the API?
+
+- docs
+
+
+
+
+- new plan
+
+	images have extra fields:
+
+		1. an array of original source images, unique by pointer
+
+		2. an int array giving for each of 1., a cumulative margin 
+
+		3. an array of direct input images, a copy of the array 
+		   passed to vips_image_pipeline_array()
+
+		4. an array of int, the same size as 3., giving the prepare
+		   order
+
+		really, 2 x array(image, int)
+
+		have a quark and use g_object_set_qdata_full() to attach
+
+	vips_image_pipeline_array()
+
+		- if there are no input images, make a new original image with
+		  a margin of 0
+
+		- create source image array, give each one a priority of 0
+
+		- create empty original image array
+		- for each source image
+		    for each original image in this original image array
+		      if not in new original image array, add it
+		      if already there, don't add, but compare the margin
+		        if this margin is greater, 
+			  note the bigger margin
+			  increment the priority of this source image
+
+		- sort source image array by priority, highest first
+
+	vips_region_prepare_many()
+
+		- prepare regions in source image array priority
+
+		- needs another arg: the image for which these regions are
+		  being prepared
+
+		- add new func vips_image_prepare_many()
+
+	vips_conv()
+
+		- add N to the margin on all original images
+
 - not sure about utf8 error messages on win
 
 - strange: 
diff --git a/libvips/arithmetic/arithmetic.c b/libvips/arithmetic/arithmetic.c
index 570c9aa3..6f9aa69d 100644
--- a/libvips/arithmetic/arithmetic.c
+++ b/libvips/arithmetic/arithmetic.c
@@ -516,11 +516,10 @@ vips_arithmetic_gen( VipsRegion *or,
 
 	/* Prepare all input regions and make buffer pointers.
 	 */
-	for( i = 0; ir[i]; i++ ) {
-		if( vips_region_prepare( ir[i], r ) ) 
-			return( -1 );
+	if( vips_image_prepare_many( or->im, ir, r ) ) 
+		return( -1 );
+	for( i = 0; ir[i]; i++ ) 
 		p[i] = (VipsPel *) VIPS_REGION_ADDR( ir[i], r->left, r->top );
-	}
 	p[i] = NULL;
 	q = (VipsPel *) VIPS_REGION_ADDR( or, r->left, r->top );
 
diff --git a/libvips/convolution/conv.c b/libvips/convolution/conv.c
index af23b0cc..d91bcfe3 100644
--- a/libvips/convolution/conv.c
+++ b/libvips/convolution/conv.c
@@ -113,6 +113,9 @@ vips_conv_build( VipsObject *object )
 		g_assert_not_reached();
 	}
 
+	vips__recomp_add_margin( convolution->out, 
+		VIPS_MAX( convolution->M->Xsize, convolution->M->Ysize ) );
+
 	return( 0 );
 }
 
diff --git a/libvips/include/vips/image.h b/libvips/include/vips/image.h
index df98217f..a440dec0 100644
--- a/libvips/include/vips/image.h
+++ b/libvips/include/vips/image.h
@@ -506,6 +506,11 @@ VipsImage **vips_array_image_get( VipsArrayImage *array, int *n );
 VipsImage **vips_value_get_array_image( const GValue *value, int *n );
 void vips_value_set_array_image( GValue *value, int n );
 
+/* Defined in recomp.c, but really a function on image.
+ */
+int vips_image_prepare_many( VipsImage *image, 
+	struct _VipsRegion **regions, VipsRect *r );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index 379d0ad7..9f5fe5f4 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -250,6 +250,10 @@ int vips__foreign_convert_saveable( VipsImage *in, VipsImage **ready,
 
 int vips__image_intize( VipsImage *in, VipsImage **out );
 
+int vips__recomp_set_input( VipsImage *image, VipsImage **in );
+void vips__recomp_init( void );
+void vips__recomp_add_margin( VipsImage *image, int margin );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/
diff --git a/libvips/iofuncs/Makefile.am b/libvips/iofuncs/Makefile.am
index 0a7807dc..a7f22312 100644
--- a/libvips/iofuncs/Makefile.am
+++ b/libvips/iofuncs/Makefile.am
@@ -1,6 +1,7 @@
 noinst_LTLIBRARIES = libiofuncs.la
 
 libiofuncs_la_SOURCES = \
+	recomp.c \
 	vipsmarshal.h \
 	vipsmarshal.c \
 	type.c \
diff --git a/libvips/iofuncs/generate.c b/libvips/iofuncs/generate.c
index 58a9c013..38ae8af6 100644
--- a/libvips/iofuncs/generate.c
+++ b/libvips/iofuncs/generate.c
@@ -385,6 +385,9 @@ vips_image_pipeline_array( VipsImage *image,
 		vips__image_copy_fields_array( image, in ) )
 		return( -1 ); 
 
+	if( vips__recomp_set_input( image, in ) )
+		return( -1 ); 
+
 	return( 0 );
 }
 
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index b6c367b2..5652aab9 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -364,6 +364,10 @@ vips_init( const char *argv0 )
 	 */
 	vips__cache_init();
 
+	/* Recomp reordering system.
+	 */
+	vips__recomp_init();
+
 	/* Start up packages.
 	 */
 	(void) vips_system_get_type();
diff --git a/libvips/iofuncs/recomp.c b/libvips/iofuncs/recomp.c
new file mode 100644
index 00000000..36ed9c7b
--- /dev/null
+++ b/libvips/iofuncs/recomp.c
@@ -0,0 +1,331 @@
+/* recomp.c ... manage recomp reordering
+ *
+ * 11/1/17
+ * 	- first version
+ */
+
+/*
+
+    This file is part of VIPS.
+    
+    VIPS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+/*
+ */
+#define DEBUG
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <vips/vips.h>
+#include <vips/internal.h>
+#include <vips/debug.h>
+
+/* Have one of these on every image, identified by a quark.
+ */
+typedef struct _VipsRecomp {
+	/* The image we are attached to.
+	 */
+	VipsImage *image;
+
+	/* The direct inputs to this image, so a copy of the array that is
+	 * passed to vips_image_pipeline_array(), and in the same order.
+	 * NULL-terminated.
+	 *
+	 * Score is the priority we give to the inputs as we de-dupe the source
+	 * arrays. 
+	 *
+	 * The recomp order is the order we prepare regions in ... just sort
+	 * recomp_order by score.
+	 */
+	int n_inputs;
+	VipsImage **input;
+	int *score;
+	int *recomp_order;
+
+	/* Source images are images with no input images, so file load, 
+	 * vips_black(), etc. NULL-terminated array.
+	 *
+	 * The cumulative margin is the total margin that has been added to 
+	 * each source image up to this point in the pipeline.
+	 */
+	int n_sources;
+	VipsImage **source;
+	int *cumulative_margin;
+
+} VipsRecomp;
+
+GQuark vips__image_recomp_quark = 0; 
+
+#ifdef DEBUG
+static void
+vips_recomp_print( VipsRecomp *recomp )
+{
+	int i;
+
+	printf( "vips_recomp_print: " );
+	vips_object_print_name( VIPS_OBJECT( recomp->image ) );
+	printf( "\n" );
+
+	printf( "n_inputs = %d\n", recomp->n_inputs );
+	printf( " n      score       order\n" );
+	for( i = 0; i < recomp->n_inputs; i++ ) {
+		printf( "%2d - %8d, %8d, ", 
+			i, recomp->score[i], recomp->recomp_order[i] );
+		vips_object_print_name( VIPS_OBJECT( recomp->input[i] ) );
+		printf( "\n" );
+	}
+
+	printf( "n_sources = %d\n", recomp->n_sources );
+	printf( " n     margin\n" );
+	for( i = 0; i < recomp->n_sources; i++ ) {
+		printf( "%2d - %8d, ", 
+			i, recomp->cumulative_margin[i] );
+		vips_object_print_name( VIPS_OBJECT( recomp->source[i] ) );
+		printf( "\n" );
+	}
+
+}
+#endif /*DEBUG*/
+
+static VipsRecomp *
+vips_recomp_get( VipsImage *image )
+{
+	VipsRecomp *recomp;
+		
+	if( (recomp = g_object_get_qdata( G_OBJECT( image ), 
+		vips__image_recomp_quark )) ) 
+		return( recomp );
+
+	recomp = VIPS_NEW( image, VipsRecomp );
+	recomp->image = image;
+	recomp->n_inputs = 0;
+	recomp->input = NULL;
+	recomp->score = NULL;
+	recomp->recomp_order = NULL;
+	recomp->n_sources = 0;
+	recomp->source = NULL;
+	recomp->cumulative_margin = NULL;
+
+	g_object_set_qdata( G_OBJECT( image ), vips__image_recomp_quark, 
+		recomp );
+
+	return( recomp );
+}
+
+static int
+vips_recomp_compare_score( const void *a, const void *b, void *arg )
+{
+	int i1 = *((int *) a);
+	int i2 = *((int *) b);
+	VipsRecomp *recomp = (VipsRecomp *) arg;
+
+	return( recomp->score[i1] - recomp->score[i2] );
+}
+
+int
+vips__recomp_set_input( VipsImage *image, VipsImage **in )
+{
+	VipsRecomp *recomp = vips_recomp_get( image );
+
+	int i;
+	int total;
+
+	printf( "vips__recomp_set_input: starting for image %p\n", image ); 
+
+	/* We have to support being called more than once on the same image.
+	 * Two cases: 
+	 * 
+	 * 1. in the first call, no images were set ... we throw away
+	 * everything from the first call and try again. foreign can do this.
+	 *
+	 * 2. warn if the args were different and do nothing.
+	 */
+	if( recomp->source ) {
+		printf( "vips__recomp_set_input: run again\n" ); 
+
+		if( recomp->n_inputs == 0 ) {
+			printf( "vips__recomp_set_input: "
+				"no args to first call\n" ); 
+
+			recomp->n_sources = 0;
+		}
+		else {
+			for( i = 0; in[i]; i++ )
+				if( i >= recomp->n_inputs ||
+					in[i] != recomp->input[i] ) {
+					printf( "vips__recomp_set_input: "
+						"args differ\n" );
+					break;
+				}
+
+			return( 0 );
+		}
+	}
+
+	/* Make a copy of the input array.
+	 */
+	for( i = 0; in[i]; i++ )
+		;
+	recomp->n_inputs = i;
+	recomp->input = VIPS_ARRAY( image, recomp->n_inputs + 1, VipsImage * );
+	recomp->score = VIPS_ARRAY( image, recomp->n_inputs, int );
+	recomp->recomp_order = VIPS_ARRAY( image, recomp->n_inputs, int );
+	if( !recomp->input )
+		return( -1 );
+	if( recomp->n_inputs && 
+		(!recomp->score ||
+		 !recomp->recomp_order) )
+		return( -1 );
+
+	for( i = 0; i < recomp->n_inputs; i++ ) {
+		recomp->input[i] = in[i];
+		recomp->score[i] = 0;
+		recomp->recomp_order[i] = i;
+	}
+	recomp->input[i] = NULL;
+
+	/* Find the total number of source images -- this gives an upper bound
+	 * to the size of the unique source image array we will need.
+	 */
+	total = 0;
+	for( i = 0; i < recomp->n_inputs; i++ ) 
+		total += vips_recomp_get( recomp->input[i] )->n_sources;
+
+	/* No source images means this must itself be a source image, so it has
+	 * a source image of itself.
+	 */
+	total = VIPS_MAX( 1, total );
+
+	recomp->source = VIPS_ARRAY( image, total + 1, VipsImage * );
+	recomp->cumulative_margin = VIPS_ARRAY( image, total, int );
+	if( !recomp->source ||
+		!recomp->cumulative_margin )
+		return( -1 );
+
+	/* Copy source images over, removing duplicates. If we find a
+	 * duplicate, we have a reordering opportunity, and we adjust the
+	 * scores of the two images containing the dupe.
+	 */
+	for( i = 0; i < recomp->n_inputs; i++ ) {
+		VipsRecomp *input = vips_recomp_get( recomp->input[i] );
+
+		int j;
+
+		for( j = 0; j < input->n_sources; j++ ) {
+			int k;
+
+			/* Search for dupe.
+			 */
+			for( k = 0; k < recomp->n_sources; k++ )
+				if( recomp->source[k] == input->source[j] )
+					break;
+
+			if( k < recomp->n_sources ) {
+				/* Found a dupe. Does this new use of
+				 * input->source[j] have a larger or smaller
+				 * margin? Adjust the score to reflect the
+				 * change, note the new max.
+				 */
+				recomp->cumulative_margin[k] = VIPS_MAX(
+					recomp->cumulative_margin[k],
+					input->cumulative_margin[j] );
+				recomp->score[i] += input->cumulative_margin[j] -
+					recomp->cumulative_margin[k];
+			}
+			else {
+				/* No dupe, just add to the table.
+				 */
+				recomp->source[recomp->n_sources] = 
+					input->source[j];
+				recomp->cumulative_margin[recomp->n_sources] = 
+					input->cumulative_margin[j];
+				recomp->n_sources += 1;
+
+				vips_recomp_print( recomp );
+			}
+		}
+	}
+
+	/* Sort recomp_order by score. qsort_r() is a GNU libc thing, don't use
+	 * it.
+	 */
+	if( recomp->n_inputs > 1 ) 
+		g_qsort_with_data( recomp->recomp_order, 
+			recomp->n_inputs, 
+			sizeof( int ), 
+			vips_recomp_compare_score, recomp );
+
+	/* No sources ... make one, us!
+	 */
+	if( recomp->n_inputs == 0 ) {
+		recomp->source[0] = image;
+		recomp->cumulative_margin[0] = 0;
+		recomp->n_sources = 1;
+	}
+
+#ifdef DEBUG
+	vips_recomp_print( recomp );
+#endif /*DEBUG*/
+
+	return( 0 );
+}
+
+int
+vips_image_prepare_many( VipsImage *image, VipsRegion **regions, VipsRect *r )
+{
+	VipsRecomp *recomp = vips_recomp_get( image );
+
+	int i;
+
+	for( i = 0; i < recomp->n_inputs; i++ ) { 
+		g_assert( regions[i] );
+
+		if( vips_region_prepare( regions[recomp->recomp_order[i]], r ) )
+			return( -1 );
+	}
+
+	return( 0 );
+}
+
+void
+vips__recomp_add_margin( VipsImage *image, int margin )
+{
+	VipsRecomp *recomp = vips_recomp_get( image );
+
+	int i;
+
+	for( i = 0; i < recomp->n_sources; i++ )  
+		recomp->cumulative_margin[i] += margin;
+}
+
+void
+vips__recomp_init( void )
+{
+	if( !vips__image_recomp_quark )
+		vips__image_recomp_quark = 
+			g_quark_from_static_string( "vips-image-recomp" ); 
+}

From 3d216da8c99b8b4eccb5495c625e9a71068aa56b Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Thu, 12 Jan 2017 09:15:10 +0000
Subject: [PATCH 5/9] rename recomp as reorder

---
 TODO                            |   4 +-
 libvips/convolution/conv.c      |   4 +-
 libvips/include/vips/internal.h |   6 +-
 libvips/iofuncs/Makefile.am     |   2 +-
 libvips/iofuncs/generate.c      |   2 +-
 libvips/iofuncs/init.c          |   2 +-
 libvips/iofuncs/recomp.c        | 331 ------------------------------
 libvips/iofuncs/reorder.c       | 343 ++++++++++++++++++++++++++++++++
 8 files changed, 353 insertions(+), 341 deletions(-)
 delete mode 100644 libvips/iofuncs/recomp.c
 create mode 100644 libvips/iofuncs/reorder.c

diff --git a/TODO b/TODO
index 9af9f705..1500373f 100644
--- a/TODO
+++ b/TODO
@@ -2,9 +2,9 @@
 
 - check sort is going in the right direction
 
-- use vips_image_prepare_many() elsewhere
+- use vips_image_prepare_many() elsewhere ... bandary, 
 
-- add vips__recomp_add_margin() elsewhere
+- add vips__recomp_add_margin() elsewhere ... morph, local hist, 
 
 - should add_margin be in the API?
 
diff --git a/libvips/convolution/conv.c b/libvips/convolution/conv.c
index d91bcfe3..8e31af89 100644
--- a/libvips/convolution/conv.c
+++ b/libvips/convolution/conv.c
@@ -113,8 +113,8 @@ vips_conv_build( VipsObject *object )
 		g_assert_not_reached();
 	}
 
-	vips__recomp_add_margin( convolution->out, 
-		VIPS_MAX( convolution->M->Xsize, convolution->M->Ysize ) );
+	vips__reorder_add_margin( convolution->out, 
+		convolution->M->Xsize * convolution->M->Ysize );
 
 	return( 0 );
 }
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index 9f5fe5f4..c8cea58b 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -250,9 +250,9 @@ int vips__foreign_convert_saveable( VipsImage *in, VipsImage **ready,
 
 int vips__image_intize( VipsImage *in, VipsImage **out );
 
-int vips__recomp_set_input( VipsImage *image, VipsImage **in );
-void vips__recomp_init( void );
-void vips__recomp_add_margin( VipsImage *image, int margin );
+int vips__reorder_set_input( VipsImage *image, VipsImage **in );
+void vips__reorder_init( void );
+void vips__reorder_add_margin( VipsImage *image, int margin );
 
 #ifdef __cplusplus
 }
diff --git a/libvips/iofuncs/Makefile.am b/libvips/iofuncs/Makefile.am
index a7f22312..cdf244a8 100644
--- a/libvips/iofuncs/Makefile.am
+++ b/libvips/iofuncs/Makefile.am
@@ -1,7 +1,7 @@
 noinst_LTLIBRARIES = libiofuncs.la
 
 libiofuncs_la_SOURCES = \
-	recomp.c \
+	reorder.c \
 	vipsmarshal.h \
 	vipsmarshal.c \
 	type.c \
diff --git a/libvips/iofuncs/generate.c b/libvips/iofuncs/generate.c
index 38ae8af6..c81a62b5 100644
--- a/libvips/iofuncs/generate.c
+++ b/libvips/iofuncs/generate.c
@@ -385,7 +385,7 @@ vips_image_pipeline_array( VipsImage *image,
 		vips__image_copy_fields_array( image, in ) )
 		return( -1 ); 
 
-	if( vips__recomp_set_input( image, in ) )
+	if( vips__reorder_set_input( image, in ) )
 		return( -1 ); 
 
 	return( 0 );
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index 5652aab9..d3d9aa6b 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -366,7 +366,7 @@ vips_init( const char *argv0 )
 
 	/* Recomp reordering system.
 	 */
-	vips__recomp_init();
+	vips__reorder_init();
 
 	/* Start up packages.
 	 */
diff --git a/libvips/iofuncs/recomp.c b/libvips/iofuncs/recomp.c
deleted file mode 100644
index 36ed9c7b..00000000
--- a/libvips/iofuncs/recomp.c
+++ /dev/null
@@ -1,331 +0,0 @@
-/* recomp.c ... manage recomp reordering
- *
- * 11/1/17
- * 	- first version
- */
-
-/*
-
-    This file is part of VIPS.
-    
-    VIPS is free software; you can redistribute it and/or modify
-    it under the terms of the GNU Lesser General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    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 Lesser General Public License for more details.
-
-    You should have received a copy of the GNU Lesser General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-    02110-1301  USA
-
- */
-
-/*
-
-    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
-
- */
-
-/*
- */
-#define DEBUG
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif /*HAVE_CONFIG_H*/
-#include <vips/intl.h>
-
-#include <vips/vips.h>
-#include <vips/internal.h>
-#include <vips/debug.h>
-
-/* Have one of these on every image, identified by a quark.
- */
-typedef struct _VipsRecomp {
-	/* The image we are attached to.
-	 */
-	VipsImage *image;
-
-	/* The direct inputs to this image, so a copy of the array that is
-	 * passed to vips_image_pipeline_array(), and in the same order.
-	 * NULL-terminated.
-	 *
-	 * Score is the priority we give to the inputs as we de-dupe the source
-	 * arrays. 
-	 *
-	 * The recomp order is the order we prepare regions in ... just sort
-	 * recomp_order by score.
-	 */
-	int n_inputs;
-	VipsImage **input;
-	int *score;
-	int *recomp_order;
-
-	/* Source images are images with no input images, so file load, 
-	 * vips_black(), etc. NULL-terminated array.
-	 *
-	 * The cumulative margin is the total margin that has been added to 
-	 * each source image up to this point in the pipeline.
-	 */
-	int n_sources;
-	VipsImage **source;
-	int *cumulative_margin;
-
-} VipsRecomp;
-
-GQuark vips__image_recomp_quark = 0; 
-
-#ifdef DEBUG
-static void
-vips_recomp_print( VipsRecomp *recomp )
-{
-	int i;
-
-	printf( "vips_recomp_print: " );
-	vips_object_print_name( VIPS_OBJECT( recomp->image ) );
-	printf( "\n" );
-
-	printf( "n_inputs = %d\n", recomp->n_inputs );
-	printf( " n      score       order\n" );
-	for( i = 0; i < recomp->n_inputs; i++ ) {
-		printf( "%2d - %8d, %8d, ", 
-			i, recomp->score[i], recomp->recomp_order[i] );
-		vips_object_print_name( VIPS_OBJECT( recomp->input[i] ) );
-		printf( "\n" );
-	}
-
-	printf( "n_sources = %d\n", recomp->n_sources );
-	printf( " n     margin\n" );
-	for( i = 0; i < recomp->n_sources; i++ ) {
-		printf( "%2d - %8d, ", 
-			i, recomp->cumulative_margin[i] );
-		vips_object_print_name( VIPS_OBJECT( recomp->source[i] ) );
-		printf( "\n" );
-	}
-
-}
-#endif /*DEBUG*/
-
-static VipsRecomp *
-vips_recomp_get( VipsImage *image )
-{
-	VipsRecomp *recomp;
-		
-	if( (recomp = g_object_get_qdata( G_OBJECT( image ), 
-		vips__image_recomp_quark )) ) 
-		return( recomp );
-
-	recomp = VIPS_NEW( image, VipsRecomp );
-	recomp->image = image;
-	recomp->n_inputs = 0;
-	recomp->input = NULL;
-	recomp->score = NULL;
-	recomp->recomp_order = NULL;
-	recomp->n_sources = 0;
-	recomp->source = NULL;
-	recomp->cumulative_margin = NULL;
-
-	g_object_set_qdata( G_OBJECT( image ), vips__image_recomp_quark, 
-		recomp );
-
-	return( recomp );
-}
-
-static int
-vips_recomp_compare_score( const void *a, const void *b, void *arg )
-{
-	int i1 = *((int *) a);
-	int i2 = *((int *) b);
-	VipsRecomp *recomp = (VipsRecomp *) arg;
-
-	return( recomp->score[i1] - recomp->score[i2] );
-}
-
-int
-vips__recomp_set_input( VipsImage *image, VipsImage **in )
-{
-	VipsRecomp *recomp = vips_recomp_get( image );
-
-	int i;
-	int total;
-
-	printf( "vips__recomp_set_input: starting for image %p\n", image ); 
-
-	/* We have to support being called more than once on the same image.
-	 * Two cases: 
-	 * 
-	 * 1. in the first call, no images were set ... we throw away
-	 * everything from the first call and try again. foreign can do this.
-	 *
-	 * 2. warn if the args were different and do nothing.
-	 */
-	if( recomp->source ) {
-		printf( "vips__recomp_set_input: run again\n" ); 
-
-		if( recomp->n_inputs == 0 ) {
-			printf( "vips__recomp_set_input: "
-				"no args to first call\n" ); 
-
-			recomp->n_sources = 0;
-		}
-		else {
-			for( i = 0; in[i]; i++ )
-				if( i >= recomp->n_inputs ||
-					in[i] != recomp->input[i] ) {
-					printf( "vips__recomp_set_input: "
-						"args differ\n" );
-					break;
-				}
-
-			return( 0 );
-		}
-	}
-
-	/* Make a copy of the input array.
-	 */
-	for( i = 0; in[i]; i++ )
-		;
-	recomp->n_inputs = i;
-	recomp->input = VIPS_ARRAY( image, recomp->n_inputs + 1, VipsImage * );
-	recomp->score = VIPS_ARRAY( image, recomp->n_inputs, int );
-	recomp->recomp_order = VIPS_ARRAY( image, recomp->n_inputs, int );
-	if( !recomp->input )
-		return( -1 );
-	if( recomp->n_inputs && 
-		(!recomp->score ||
-		 !recomp->recomp_order) )
-		return( -1 );
-
-	for( i = 0; i < recomp->n_inputs; i++ ) {
-		recomp->input[i] = in[i];
-		recomp->score[i] = 0;
-		recomp->recomp_order[i] = i;
-	}
-	recomp->input[i] = NULL;
-
-	/* Find the total number of source images -- this gives an upper bound
-	 * to the size of the unique source image array we will need.
-	 */
-	total = 0;
-	for( i = 0; i < recomp->n_inputs; i++ ) 
-		total += vips_recomp_get( recomp->input[i] )->n_sources;
-
-	/* No source images means this must itself be a source image, so it has
-	 * a source image of itself.
-	 */
-	total = VIPS_MAX( 1, total );
-
-	recomp->source = VIPS_ARRAY( image, total + 1, VipsImage * );
-	recomp->cumulative_margin = VIPS_ARRAY( image, total, int );
-	if( !recomp->source ||
-		!recomp->cumulative_margin )
-		return( -1 );
-
-	/* Copy source images over, removing duplicates. If we find a
-	 * duplicate, we have a reordering opportunity, and we adjust the
-	 * scores of the two images containing the dupe.
-	 */
-	for( i = 0; i < recomp->n_inputs; i++ ) {
-		VipsRecomp *input = vips_recomp_get( recomp->input[i] );
-
-		int j;
-
-		for( j = 0; j < input->n_sources; j++ ) {
-			int k;
-
-			/* Search for dupe.
-			 */
-			for( k = 0; k < recomp->n_sources; k++ )
-				if( recomp->source[k] == input->source[j] )
-					break;
-
-			if( k < recomp->n_sources ) {
-				/* Found a dupe. Does this new use of
-				 * input->source[j] have a larger or smaller
-				 * margin? Adjust the score to reflect the
-				 * change, note the new max.
-				 */
-				recomp->cumulative_margin[k] = VIPS_MAX(
-					recomp->cumulative_margin[k],
-					input->cumulative_margin[j] );
-				recomp->score[i] += input->cumulative_margin[j] -
-					recomp->cumulative_margin[k];
-			}
-			else {
-				/* No dupe, just add to the table.
-				 */
-				recomp->source[recomp->n_sources] = 
-					input->source[j];
-				recomp->cumulative_margin[recomp->n_sources] = 
-					input->cumulative_margin[j];
-				recomp->n_sources += 1;
-
-				vips_recomp_print( recomp );
-			}
-		}
-	}
-
-	/* Sort recomp_order by score. qsort_r() is a GNU libc thing, don't use
-	 * it.
-	 */
-	if( recomp->n_inputs > 1 ) 
-		g_qsort_with_data( recomp->recomp_order, 
-			recomp->n_inputs, 
-			sizeof( int ), 
-			vips_recomp_compare_score, recomp );
-
-	/* No sources ... make one, us!
-	 */
-	if( recomp->n_inputs == 0 ) {
-		recomp->source[0] = image;
-		recomp->cumulative_margin[0] = 0;
-		recomp->n_sources = 1;
-	}
-
-#ifdef DEBUG
-	vips_recomp_print( recomp );
-#endif /*DEBUG*/
-
-	return( 0 );
-}
-
-int
-vips_image_prepare_many( VipsImage *image, VipsRegion **regions, VipsRect *r )
-{
-	VipsRecomp *recomp = vips_recomp_get( image );
-
-	int i;
-
-	for( i = 0; i < recomp->n_inputs; i++ ) { 
-		g_assert( regions[i] );
-
-		if( vips_region_prepare( regions[recomp->recomp_order[i]], r ) )
-			return( -1 );
-	}
-
-	return( 0 );
-}
-
-void
-vips__recomp_add_margin( VipsImage *image, int margin )
-{
-	VipsRecomp *recomp = vips_recomp_get( image );
-
-	int i;
-
-	for( i = 0; i < recomp->n_sources; i++ )  
-		recomp->cumulative_margin[i] += margin;
-}
-
-void
-vips__recomp_init( void )
-{
-	if( !vips__image_recomp_quark )
-		vips__image_recomp_quark = 
-			g_quark_from_static_string( "vips-image-recomp" ); 
-}
diff --git a/libvips/iofuncs/reorder.c b/libvips/iofuncs/reorder.c
new file mode 100644
index 00000000..f4373a5c
--- /dev/null
+++ b/libvips/iofuncs/reorder.c
@@ -0,0 +1,343 @@
+/* reorder.c ... manage reorder reordering
+ *
+ * 11/1/17
+ * 	- first version
+ */
+
+/*
+
+    This file is part of VIPS.
+    
+    VIPS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+/*
+ */
+#define DEBUG
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <vips/vips.h>
+#include <vips/internal.h>
+#include <vips/debug.h>
+
+/* Have one of these on every image, identified by a quark.
+ */
+typedef struct _VipsReorder {
+	/* The image we are attached to.
+	 */
+	VipsImage *image;
+
+	/* The direct inputs to this image, so a copy of the array that is
+	 * passed to vips_image_pipeline_array(), and in the same order.
+	 * NULL-terminated.
+	 *
+	 * Score is the priority we give to the inputs as we de-dupe the source
+	 * arrays. 
+	 *
+	 * The recomp order is the order we prepare regions in ... just make a
+	 * range then sort by score.
+	 */
+	int n_inputs;
+	VipsImage **input;
+	int *score;
+	int *recomp_order;
+
+	/* Source images are images with no input images, so file load, 
+	 * vips_black(), etc. NULL-terminated array.
+	 *
+	 * The cumulative margin is the total margin that has been added to 
+	 * each source image up to this point in the pipeline.
+	 */
+	int n_sources;
+	VipsImage **source;
+	int *cumulative_margin;
+
+} VipsReorder;
+
+GQuark vips__image_reorder_quark = 0; 
+
+#ifdef DEBUG
+static void
+vips_reorder_print( VipsReorder *reorder )
+{
+	int i;
+
+	printf( "vips_reorder_print: " );
+	vips_object_print_name( VIPS_OBJECT( reorder->image ) );
+	printf( "\n" );
+
+	printf( "n_inputs = %d\n", reorder->n_inputs );
+	printf( " n      score       order\n" );
+	for( i = 0; i < reorder->n_inputs; i++ ) {
+		printf( "%2d - %8d, %8d, ", 
+			i, reorder->score[i], reorder->recomp_order[i] );
+		vips_object_print_name( VIPS_OBJECT( reorder->input[i] ) );
+		printf( "\n" );
+	}
+
+	printf( "n_sources = %d\n", reorder->n_sources );
+	printf( " n     margin\n" );
+	for( i = 0; i < reorder->n_sources; i++ ) {
+		printf( "%2d - %8d, ", 
+			i, reorder->cumulative_margin[i] );
+		vips_object_print_name( VIPS_OBJECT( reorder->source[i] ) );
+		printf( "\n" );
+	}
+
+}
+#endif /*DEBUG*/
+
+static VipsReorder *
+vips_reorder_get( VipsImage *image )
+{
+	VipsReorder *reorder;
+		
+	if( (reorder = g_object_get_qdata( G_OBJECT( image ), 
+		vips__image_reorder_quark )) ) 
+		return( reorder );
+
+	reorder = VIPS_NEW( image, VipsReorder );
+	reorder->image = image;
+	reorder->n_inputs = 0;
+	reorder->input = NULL;
+	reorder->score = NULL;
+	reorder->recomp_order = NULL;
+	reorder->n_sources = 0;
+	reorder->source = NULL;
+	reorder->cumulative_margin = NULL;
+
+	g_object_set_qdata( G_OBJECT( image ), vips__image_reorder_quark, 
+		reorder );
+
+	return( reorder );
+}
+
+static int
+vips_reorder_compare_score( const void *a, const void *b, void *arg )
+{
+	int i1 = *((int *) a);
+	int i2 = *((int *) b);
+	VipsReorder *reorder = (VipsReorder *) arg;
+
+	return( reorder->score[i2] - reorder->score[i1] );
+}
+
+int
+vips__reorder_set_input( VipsImage *image, VipsImage **in )
+{
+	VipsReorder *reorder = vips_reorder_get( image );
+
+	int i;
+	int total;
+
+	printf( "vips__reorder_set_input: starting for image %p\n", image ); 
+
+	/* We have to support being called more than once on the same image.
+	 * Two cases: 
+	 * 
+	 * 1. in the first call, no images were set ... we throw away
+	 * everything from the first call and try again. foreign can do this.
+	 *
+	 * 2. warn if the args were different and do nothing.
+	 */
+	if( reorder->source ) {
+		printf( "vips__reorder_set_input: run again\n" ); 
+
+		if( reorder->n_inputs == 0 ) {
+			printf( "vips__reorder_set_input: "
+				"no args to first call\n" ); 
+
+			reorder->n_sources = 0;
+		}
+		else {
+			for( i = 0; in[i]; i++ )
+				if( i >= reorder->n_inputs ||
+					in[i] != reorder->input[i] ) {
+					printf( "vips__reorder_set_input: "
+						"args differ\n" );
+					break;
+				}
+
+			return( 0 );
+		}
+	}
+
+	/* Make a copy of the input array.
+	 */
+	for( i = 0; in[i]; i++ )
+		;
+	reorder->n_inputs = i;
+	reorder->input = VIPS_ARRAY( image, reorder->n_inputs + 1, VipsImage * );
+	reorder->score = VIPS_ARRAY( image, reorder->n_inputs, int );
+	reorder->recomp_order = VIPS_ARRAY( image, reorder->n_inputs, int );
+	if( !reorder->input )
+		return( -1 );
+	if( reorder->n_inputs && 
+		(!reorder->score ||
+		 !reorder->recomp_order) )
+		return( -1 );
+
+	for( i = 0; i < reorder->n_inputs; i++ ) {
+		reorder->input[i] = in[i];
+		reorder->score[i] = 0;
+		reorder->recomp_order[i] = i;
+	}
+	reorder->input[i] = NULL;
+
+	/* Find the total number of source images -- this gives an upper bound
+	 * to the size of the unique source image array we will need.
+	 */
+	total = 0;
+	for( i = 0; i < reorder->n_inputs; i++ ) 
+		total += vips_reorder_get( reorder->input[i] )->n_sources;
+
+	/* No source images means this must itself be a source image, so it has
+	 * a source image of itself.
+	 */
+	total = VIPS_MAX( 1, total );
+
+	reorder->source = VIPS_ARRAY( image, total + 1, VipsImage * );
+	reorder->cumulative_margin = VIPS_ARRAY( image, total, int );
+	if( !reorder->source ||
+		!reorder->cumulative_margin )
+		return( -1 );
+
+	/* Copy source images over, removing duplicates. If we find a
+	 * duplicate, we have a reordering opportunity, and we adjust the
+	 * scores of the two images containing the dupe.
+	 */
+	for( i = 0; i < reorder->n_inputs; i++ ) {
+		VipsReorder *input = vips_reorder_get( reorder->input[i] );
+
+		int j;
+
+		for( j = 0; j < input->n_sources; j++ ) {
+			int k;
+
+			/* Search for dupe.
+			 */
+			for( k = 0; k < reorder->n_sources; k++ )
+				if( reorder->source[k] == input->source[j] )
+					break;
+
+			if( k < reorder->n_sources ) {
+				/* Found a dupe. Does this new use of
+				 * input->source[j] have a larger or smaller
+				 * margin? Adjust the score to reflect the
+				 * change, note the new max.
+				 */
+
+				printf( "found a dupe\n" );
+				printf( "margin on first one %d\n", 
+					reorder->cumulative_margin[k] );
+				printf( "margin on new one %d\n", 
+					input->cumulative_margin[j] );
+					
+				printf( "setting score on %d += %d\n", 
+					i, input->cumulative_margin[j] - 
+						reorder->cumulative_margin[k] );
+
+				reorder->cumulative_margin[k] = VIPS_MAX(
+					reorder->cumulative_margin[k],
+					input->cumulative_margin[j] );
+				reorder->score[i] += input->cumulative_margin[j] -
+					reorder->cumulative_margin[k];
+
+			}
+			else {
+				/* No dupe, just add to the table.
+				 */
+				reorder->source[reorder->n_sources] = 
+					input->source[j];
+				reorder->cumulative_margin[reorder->n_sources] = 
+					input->cumulative_margin[j];
+				reorder->n_sources += 1;
+
+				vips_reorder_print( reorder );
+			}
+		}
+	}
+
+	/* Sort recomp_order by score. qsort_r() is a GNU libc thing, don't use
+	 * it.
+	 */
+	if( reorder->n_inputs > 1 ) 
+		g_qsort_with_data( reorder->recomp_order, 
+			reorder->n_inputs, 
+			sizeof( int ), 
+			vips_reorder_compare_score, reorder );
+
+	/* No sources ... make one, us!
+	 */
+	if( reorder->n_inputs == 0 ) {
+		reorder->source[0] = image;
+		reorder->cumulative_margin[0] = 0;
+		reorder->n_sources = 1;
+	}
+
+#ifdef DEBUG
+	vips_reorder_print( reorder );
+#endif /*DEBUG*/
+
+	return( 0 );
+}
+
+int
+vips_image_prepare_many( VipsImage *image, VipsRegion **regions, VipsRect *r )
+{
+	VipsReorder *reorder = vips_reorder_get( image );
+
+	int i;
+
+	for( i = 0; i < reorder->n_inputs; i++ ) { 
+		g_assert( regions[i] );
+
+		if( vips_region_prepare( regions[reorder->recomp_order[i]], r ) )
+			return( -1 );
+	}
+
+	return( 0 );
+}
+
+void
+vips__reorder_add_margin( VipsImage *image, int margin )
+{
+	VipsReorder *reorder = vips_reorder_get( image );
+
+	int i;
+
+	for( i = 0; i < reorder->n_sources; i++ )  
+		reorder->cumulative_margin[i] += margin;
+}
+
+void
+vips__reorder_init( void )
+{
+	if( !vips__image_reorder_quark )
+		vips__image_reorder_quark = 
+			g_quark_from_static_string( "vips-image-reorder" ); 
+}

From f302bd6570fef0084f8c8f62921c5d84cd2d0620 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Thu, 12 Jan 2017 14:06:54 +0000
Subject: [PATCH 6/9] all working!

---
 TODO                            | 61 +--------------------
 libvips/arithmetic/arithmetic.c |  2 +-
 libvips/convolution/conv.c      |  2 +-
 libvips/foreign/vips2webp.c     |  2 +-
 libvips/include/vips/image.h    |  5 +-
 libvips/include/vips/internal.h |  3 +-
 libvips/iofuncs/generate.c      |  8 +++
 libvips/iofuncs/reorder.c       | 95 +++++++++++++++++++++------------
 8 files changed, 77 insertions(+), 101 deletions(-)

diff --git a/TODO b/TODO
index 1500373f..b30851cb 100644
--- a/TODO
+++ b/TODO
@@ -1,67 +1,10 @@
-- try with our Python script
+- use vips_reorder_prepare_many() elsewhere ... bandary, 
 
-- check sort is going in the right direction
-
-- use vips_image_prepare_many() elsewhere ... bandary, 
-
-- add vips__recomp_add_margin() elsewhere ... morph, local hist, 
-
-- should add_margin be in the API?
-
-- docs
+- add vips_reorder_margin_hint() elsewhere ... morph, local hist, 
 
 
 
 
-- new plan
-
-	images have extra fields:
-
-		1. an array of original source images, unique by pointer
-
-		2. an int array giving for each of 1., a cumulative margin 
-
-		3. an array of direct input images, a copy of the array 
-		   passed to vips_image_pipeline_array()
-
-		4. an array of int, the same size as 3., giving the prepare
-		   order
-
-		really, 2 x array(image, int)
-
-		have a quark and use g_object_set_qdata_full() to attach
-
-	vips_image_pipeline_array()
-
-		- if there are no input images, make a new original image with
-		  a margin of 0
-
-		- create source image array, give each one a priority of 0
-
-		- create empty original image array
-		- for each source image
-		    for each original image in this original image array
-		      if not in new original image array, add it
-		      if already there, don't add, but compare the margin
-		        if this margin is greater, 
-			  note the bigger margin
-			  increment the priority of this source image
-
-		- sort source image array by priority, highest first
-
-	vips_region_prepare_many()
-
-		- prepare regions in source image array priority
-
-		- needs another arg: the image for which these regions are
-		  being prepared
-
-		- add new func vips_image_prepare_many()
-
-	vips_conv()
-
-		- add N to the margin on all original images
-
 - not sure about utf8 error messages on win
 
 - strange: 
diff --git a/libvips/arithmetic/arithmetic.c b/libvips/arithmetic/arithmetic.c
index 6f9aa69d..df6ec224 100644
--- a/libvips/arithmetic/arithmetic.c
+++ b/libvips/arithmetic/arithmetic.c
@@ -516,7 +516,7 @@ vips_arithmetic_gen( VipsRegion *or,
 
 	/* Prepare all input regions and make buffer pointers.
 	 */
-	if( vips_image_prepare_many( or->im, ir, r ) ) 
+	if( vips_reorder_prepare_many( or->im, ir, r ) ) 
 		return( -1 );
 	for( i = 0; ir[i]; i++ ) 
 		p[i] = (VipsPel *) VIPS_REGION_ADDR( ir[i], r->left, r->top );
diff --git a/libvips/convolution/conv.c b/libvips/convolution/conv.c
index 8e31af89..1a49290c 100644
--- a/libvips/convolution/conv.c
+++ b/libvips/convolution/conv.c
@@ -113,7 +113,7 @@ vips_conv_build( VipsObject *object )
 		g_assert_not_reached();
 	}
 
-	vips__reorder_add_margin( convolution->out, 
+	vips_reorder_margin_hint( convolution->out, 
 		convolution->M->Xsize * convolution->M->Ysize );
 
 	return( 0 );
diff --git a/libvips/foreign/vips2webp.c b/libvips/foreign/vips2webp.c
index 5447c24c..a38dfb0f 100644
--- a/libvips/foreign/vips2webp.c
+++ b/libvips/foreign/vips2webp.c
@@ -160,7 +160,7 @@ vips_webp_writer_appendle( VipsWebPWriter *writer, uint32_t val, int n )
 	unsigned char buf[4];
 	int i; 
 
-	g_assert( n < 4 );
+	g_assert( n <= 4 );
 
 	for( i = 0; i < n; i++ ) {
 		buf[i] = (unsigned char) (val & 0xff);
diff --git a/libvips/include/vips/image.h b/libvips/include/vips/image.h
index a440dec0..3f9fe380 100644
--- a/libvips/include/vips/image.h
+++ b/libvips/include/vips/image.h
@@ -506,10 +506,11 @@ VipsImage **vips_array_image_get( VipsArrayImage *array, int *n );
 VipsImage **vips_value_get_array_image( const GValue *value, int *n );
 void vips_value_set_array_image( GValue *value, int n );
 
-/* Defined in recomp.c, but really a function on image.
+/* Defined in reorder.c, but really a function on image.
  */
-int vips_image_prepare_many( VipsImage *image, 
+int vips_reorder_prepare_many( VipsImage *image, 
 	struct _VipsRegion **regions, VipsRect *r );
+void vips_reorder_margin_hint( VipsImage *image, int margin );
 
 #ifdef __cplusplus
 }
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index c8cea58b..8329cf87 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -250,9 +250,8 @@ int vips__foreign_convert_saveable( VipsImage *in, VipsImage **ready,
 
 int vips__image_intize( VipsImage *in, VipsImage **out );
 
-int vips__reorder_set_input( VipsImage *image, VipsImage **in );
 void vips__reorder_init( void );
-void vips__reorder_add_margin( VipsImage *image, int margin );
+int vips__reorder_set_input( VipsImage *image, VipsImage **in );
 
 #ifdef __cplusplus
 }
diff --git a/libvips/iofuncs/generate.c b/libvips/iofuncs/generate.c
index c81a62b5..de025d64 100644
--- a/libvips/iofuncs/generate.c
+++ b/libvips/iofuncs/generate.c
@@ -379,6 +379,14 @@ int
 vips_image_pipeline_array( VipsImage *image, 
 	VipsDemandStyle hint, VipsImage **in )
 {
+	/* This function can be called more than once per output image. For
+	 * example, jpeg header load will call this once on ->out to set the
+	 * default hint, then later call it again to connect the output image
+	 * up to the real image.
+	 *
+	 * It's only ever called first time with in[0] == NULL and second time
+	 * with a real value for @in.
+	 */
 	vips__demand_hint_array( image, hint, in );
 
 	if( in[0] && 
diff --git a/libvips/iofuncs/reorder.c b/libvips/iofuncs/reorder.c
index f4373a5c..2333359a 100644
--- a/libvips/iofuncs/reorder.c
+++ b/libvips/iofuncs/reorder.c
@@ -32,8 +32,8 @@
  */
 
 /*
- */
 #define DEBUG
+ */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
@@ -111,6 +111,17 @@ vips_reorder_print( VipsReorder *reorder )
 }
 #endif /*DEBUG*/
 
+static void
+vips_reorder_destroy( VipsReorder *reorder )
+{
+	VIPS_FREE( reorder->input );
+	VIPS_FREE( reorder->score );
+	VIPS_FREE( reorder->recomp_order );
+	VIPS_FREE( reorder->source );
+	VIPS_FREE( reorder->cumulative_margin );
+	VIPS_FREE( reorder );
+}
+
 static VipsReorder *
 vips_reorder_get( VipsImage *image )
 {
@@ -120,7 +131,7 @@ vips_reorder_get( VipsImage *image )
 		vips__image_reorder_quark )) ) 
 		return( reorder );
 
-	reorder = VIPS_NEW( image, VipsReorder );
+	reorder = VIPS_NEW( NULL, VipsReorder );
 	reorder->image = image;
 	reorder->n_inputs = 0;
 	reorder->input = NULL;
@@ -130,8 +141,8 @@ vips_reorder_get( VipsImage *image )
 	reorder->source = NULL;
 	reorder->cumulative_margin = NULL;
 
-	g_object_set_qdata( G_OBJECT( image ), vips__image_reorder_quark, 
-		reorder );
+	g_object_set_qdata_full( G_OBJECT( image ), vips__image_reorder_quark, 
+		reorder, (GDestroyNotify) vips_reorder_destroy );
 
 	return( reorder );
 }
@@ -154,8 +165,6 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 	int i;
 	int total;
 
-	printf( "vips__reorder_set_input: starting for image %p\n", image ); 
-
 	/* We have to support being called more than once on the same image.
 	 * Two cases: 
 	 * 
@@ -165,19 +174,15 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 	 * 2. warn if the args were different and do nothing.
 	 */
 	if( reorder->source ) {
-		printf( "vips__reorder_set_input: run again\n" ); 
-
-		if( reorder->n_inputs == 0 ) {
-			printf( "vips__reorder_set_input: "
-				"no args to first call\n" ); 
-
+		if( reorder->n_inputs == 0 ) 
 			reorder->n_sources = 0;
-		}
 		else {
 			for( i = 0; in[i]; i++ )
 				if( i >= reorder->n_inputs ||
 					in[i] != reorder->input[i] ) {
-					printf( "vips__reorder_set_input: "
+					/* Should never happen.
+					 */
+					g_warning( "vips__reorder_set_input: "
 						"args differ\n" );
 					break;
 				}
@@ -191,9 +196,9 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 	for( i = 0; in[i]; i++ )
 		;
 	reorder->n_inputs = i;
-	reorder->input = VIPS_ARRAY( image, reorder->n_inputs + 1, VipsImage * );
-	reorder->score = VIPS_ARRAY( image, reorder->n_inputs, int );
-	reorder->recomp_order = VIPS_ARRAY( image, reorder->n_inputs, int );
+	reorder->input = VIPS_ARRAY( NULL, reorder->n_inputs + 1, VipsImage * );
+	reorder->score = VIPS_ARRAY( NULL, reorder->n_inputs, int );
+	reorder->recomp_order = VIPS_ARRAY( NULL, reorder->n_inputs, int );
 	if( !reorder->input )
 		return( -1 );
 	if( reorder->n_inputs && 
@@ -220,8 +225,8 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 	 */
 	total = VIPS_MAX( 1, total );
 
-	reorder->source = VIPS_ARRAY( image, total + 1, VipsImage * );
-	reorder->cumulative_margin = VIPS_ARRAY( image, total, int );
+	reorder->source = VIPS_ARRAY( NULL, total + 1, VipsImage * );
+	reorder->cumulative_margin = VIPS_ARRAY( NULL, total, int );
 	if( !reorder->source ||
 		!reorder->cumulative_margin )
 		return( -1 );
@@ -250,22 +255,13 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 				 * margin? Adjust the score to reflect the
 				 * change, note the new max.
 				 */
-
-				printf( "found a dupe\n" );
-				printf( "margin on first one %d\n", 
-					reorder->cumulative_margin[k] );
-				printf( "margin on new one %d\n", 
-					input->cumulative_margin[j] );
-					
-				printf( "setting score on %d += %d\n", 
-					i, input->cumulative_margin[j] - 
-						reorder->cumulative_margin[k] );
+				reorder->score[i] += 
+					input->cumulative_margin[j] -
+					reorder->cumulative_margin[k];
 
 				reorder->cumulative_margin[k] = VIPS_MAX(
 					reorder->cumulative_margin[k],
 					input->cumulative_margin[j] );
-				reorder->score[i] += input->cumulative_margin[j] -
-					reorder->cumulative_margin[k];
 
 			}
 			else {
@@ -276,8 +272,6 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 				reorder->cumulative_margin[reorder->n_sources] = 
 					input->cumulative_margin[j];
 				reorder->n_sources += 1;
-
-				vips_reorder_print( reorder );
 			}
 		}
 	}
@@ -306,8 +300,24 @@ vips__reorder_set_input( VipsImage *image, VipsImage **in )
 	return( 0 );
 }
 
+/**
+ * vips_reorder_prepare_many:
+ * @image: the image that's being written
+ * @regions: the set of regions to prepare
+ * @r: the #VipsRect to prepare on each region
+ *
+ * vips_reorder_prepare_many() runs vips_region_prepare() on each region in
+ * @regions, requesting the pixels in @r.
+ *
+ * It tries to request the regions in the order which will cause least
+ * recomputation. This can give a large speedup, in some cases. 
+ *
+ * See also: vips_region_prepare(), vips_reorder_margin_hint().
+ *
+ * Returns: 0 on success, or -1 on error.
+ */
 int
-vips_image_prepare_many( VipsImage *image, VipsRegion **regions, VipsRect *r )
+vips_reorder_prepare_many( VipsImage *image, VipsRegion **regions, VipsRect *r )
 {
 	VipsReorder *reorder = vips_reorder_get( image );
 
@@ -323,8 +333,23 @@ vips_image_prepare_many( VipsImage *image, VipsRegion **regions, VipsRect *r )
 	return( 0 );
 }
 
+/**
+ * vips_reorder_margin_hint:
+ * @image: the image to hint on
+ * @margin: the size of the margin this operation has added
+ *
+ * vips_reorder_margin_hint() sets a hint that @image contains a margin, that
+ * is, that each vips_region_prepare() on @image will request a slightly larger
+ * region from it's inputs. A good value for @margin is (width * height) for
+ * the window the operation uses. 
+ *
+ * This information is used by vips_image_prepare_many() to attempt to reorder
+ * computations to minimise recomputation.
+ *
+ * See also: vips_image_prepare_many().
+ */
 void
-vips__reorder_add_margin( VipsImage *image, int margin )
+vips_reorder_margin_hint( VipsImage *image, int margin )
 {
 	VipsReorder *reorder = vips_reorder_get( image );
 

From 6b325145e4f07049d6ff3d446e5c4ec8eacb9203 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Thu, 12 Jan 2017 14:36:44 +0000
Subject: [PATCH 7/9] use new hints and prepare everywhere

---
 ChangeLog                         | 3 +++
 TODO                              | 6 ------
 libvips/colour/colour.c           | 5 ++---
 libvips/conversion/bandary.c      | 7 +++----
 libvips/conversion/ifthenelse.c   | 3 +++
 libvips/convolution/correlation.c | 3 +++
 libvips/convolution/sharpen.c     | 3 +--
 libvips/deprecated/vips7compat.c  | 7 +++----
 libvips/histogram/hist_local.c    | 2 ++
 libvips/histogram/stdif.c         | 2 ++
 libvips/morphology/morph.c        | 3 +++
 libvips/morphology/rank.c         | 2 ++
 libvips/resample/reduceh.cpp      | 2 ++
 libvips/resample/reducev.cpp      | 2 ++
 14 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 32a4f5c7..b1407fd5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -20,6 +20,9 @@
 - better support for bscale / bzero in fits images
 - deprecate vips_warn() / vips_info(); use g_warning() / g_info() instead
 - fix --vips-cache-max etc. 
+- add compute reordering, plus some new API to support it:
+  vips_reorder_margin_hint() and vips_reorder_prepare_many(), thanks
+  aferrero2707
 
 8/12/16 started 8.4.5
 - allow libgsf-1.14.26 to help centos, thanks tdiprima
diff --git a/TODO b/TODO
index b30851cb..458f2c59 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,3 @@
-- use vips_reorder_prepare_many() elsewhere ... bandary, 
-
-- add vips_reorder_margin_hint() elsewhere ... morph, local hist, 
-
-
-
 
 - not sure about utf8 error messages on win
 
diff --git a/libvips/colour/colour.c b/libvips/colour/colour.c
index ed5666a1..61988a89 100644
--- a/libvips/colour/colour.c
+++ b/libvips/colour/colour.c
@@ -234,9 +234,8 @@ vips_colour_gen( VipsRegion *or,
 	int i, y;
 	VipsPel *p[MAX_INPUT_IMAGES], *q;
 
-	for( i = 0; ir[i]; i++ ) 
-		if( vips_region_prepare( ir[i], r ) ) 
-			return( -1 );
+	if( vips_reorder_prepare_many( or->im, ir, r ) )
+		return( -1 );
 
 	VIPS_GATE_START( "vips_colour_gen: work" ); 
 
diff --git a/libvips/conversion/bandary.c b/libvips/conversion/bandary.c
index 66b9ef5f..2f14b494 100644
--- a/libvips/conversion/bandary.c
+++ b/libvips/conversion/bandary.c
@@ -92,11 +92,10 @@ vips_bandary_gen( VipsRegion *or, void *seq, void *a, void *b, gboolean *stop )
 	VipsPel *p[MAX_INPUT_IMAGES], *q;
 	int y, i;
 
-	for( i = 0; i < bandary->n; i++ ) {
-		if( vips_region_prepare( ir[i], r ) )
-			return( -1 );
+	if( vips_reorder_prepare_many( or->im, ir, r ) )
+		return( -1 );
+	for( i = 0; i < bandary->n; i++ ) 
 		p[i] = VIPS_REGION_ADDR( ir[i], r->left, r->top );
-	}
 	p[i] = NULL;
 	q = VIPS_REGION_ADDR( or, r->left, r->top );
 
diff --git a/libvips/conversion/ifthenelse.c b/libvips/conversion/ifthenelse.c
index eb5bb2b7..38a76bfd 100644
--- a/libvips/conversion/ifthenelse.c
+++ b/libvips/conversion/ifthenelse.c
@@ -283,6 +283,9 @@ vips_blend_gen( VipsRegion *or, void *seq, void *client1, void *client2,
 	else {
 		/* Mix of set and clear ... ask for both then and else parts 
 		 * and interleave.
+		 *
+		 * We can't use vips_reorder_prepare_many() since we always
+		 * want the c image first.
 		 */
 		if( vips_region_prepare( ir[0], r ) || 
 			vips_region_prepare( ir[1], r ) ) 
diff --git a/libvips/convolution/correlation.c b/libvips/convolution/correlation.c
index 2abd96c2..31e4b187 100644
--- a/libvips/convolution/correlation.c
+++ b/libvips/convolution/correlation.c
@@ -125,6 +125,9 @@ vips_correlation_build( VipsObject *object )
 		correlation->in_ready, correlation ) )
 		return( -1 );
 
+	vips_reorder_margin_hint( correlation->out, 
+		correlation->ref->Xsize * correlation->ref->Ysize );
+
 	return( 0 );
 }
 
diff --git a/libvips/convolution/sharpen.c b/libvips/convolution/sharpen.c
index 6a260fbe..a95242fb 100644
--- a/libvips/convolution/sharpen.c
+++ b/libvips/convolution/sharpen.c
@@ -121,8 +121,7 @@ vips_sharpen_generate( VipsRegion *or,
 
 	int x, y; 
 
-	if( vips_region_prepare( in[0], r ) ||
-		vips_region_prepare( in[1], r ) )
+	if( vips_reorder_prepare_many( or->im, in, r ) )
 		return( -1 );
 
 	VIPS_GATE_START( "vips_sharpen_generate: work" ); 
diff --git a/libvips/deprecated/vips7compat.c b/libvips/deprecated/vips7compat.c
index 10eec9d0..a3b6d954 100644
--- a/libvips/deprecated/vips7compat.c
+++ b/libvips/deprecated/vips7compat.c
@@ -649,12 +649,11 @@ process_region( VipsRegion *or, void *seq, void *a, void *b )
 
 	/* Prepare all input regions and make buffer pointers.
 	 */
-	for( i = 0; ir[i]; i++ ) {
-		if( vips_region_prepare( ir[i], &or->valid ) ) 
-			return( -1 );
+	if( vips_reorder_prepare_many( or->im, ir, &or->valid ) ) 
+		return( -1 );
+	for( i = 0; ir[i]; i++ ) 
 		p[i] = (PEL *) VIPS_REGION_ADDR( ir[i], 
 			or->valid.left, or->valid.top );
-	}
 	p[i] = NULL;
 	q = (PEL *) VIPS_REGION_ADDR( or, or->valid.left, or->valid.top );
 
diff --git a/libvips/histogram/hist_local.c b/libvips/histogram/hist_local.c
index 59472ea2..f97cdead 100644
--- a/libvips/histogram/hist_local.c
+++ b/libvips/histogram/hist_local.c
@@ -280,6 +280,8 @@ vips_hist_local_build( VipsObject *object )
 	local->out->Xoffset = 0;
 	local->out->Yoffset = 0;
 
+	vips_reorder_margin_hint( local->out, local->width * local->height ); 
+
 	return( 0 );
 }
 
diff --git a/libvips/histogram/stdif.c b/libvips/histogram/stdif.c
index da701555..92d3bdc2 100644
--- a/libvips/histogram/stdif.c
+++ b/libvips/histogram/stdif.c
@@ -272,6 +272,8 @@ vips_stdif_build( VipsObject *object )
 	stdif->out->Xoffset = 0;
 	stdif->out->Yoffset = 0;
 
+	vips_reorder_margin_hint( stdif->out, stdif->width * stdif->height ); 
+
 	return( 0 );
 }
 
diff --git a/libvips/morphology/morph.c b/libvips/morphology/morph.c
index 47333e18..5b38d00e 100644
--- a/libvips/morphology/morph.c
+++ b/libvips/morphology/morph.c
@@ -120,6 +120,9 @@ vips_morph_build( VipsObject *object )
 		g_assert_not_reached();
 	}
 
+	vips_reorder_margin_hint( morph->out, 
+		morph->M->Xsize * morph->M->Ysize );
+
 	return( 0 );
 }
 
diff --git a/libvips/morphology/rank.c b/libvips/morphology/rank.c
index 09bcebc6..fea8e211 100644
--- a/libvips/morphology/rank.c
+++ b/libvips/morphology/rank.c
@@ -391,6 +391,8 @@ vips_rank_build( VipsObject *object )
 	rank->out->Xoffset = 0;
 	rank->out->Yoffset = 0;
 
+	vips_reorder_margin_hint( rank->out, rank->width * rank->height ); 
+
 	return( 0 );
 }
 
diff --git a/libvips/resample/reduceh.cpp b/libvips/resample/reduceh.cpp
index 52ec7d3d..b57c4fcc 100644
--- a/libvips/resample/reduceh.cpp
+++ b/libvips/resample/reduceh.cpp
@@ -540,6 +540,8 @@ vips_reduceh_build( VipsObject *object )
 		in, reduceh ) )
 		return( -1 );
 
+	vips_reorder_margin_hint( resample->out, reduceh->n_point ); 
+
 	return( 0 );
 }
 
diff --git a/libvips/resample/reducev.cpp b/libvips/resample/reducev.cpp
index 63a03c43..3cf3d7f7 100644
--- a/libvips/resample/reducev.cpp
+++ b/libvips/resample/reducev.cpp
@@ -813,6 +813,8 @@ vips_reducev_raw( VipsReducev *reducev, VipsImage *in )
 		in, reducev ) )
 		return( -1 );
 
+	vips_reorder_margin_hint( resample->out, reducev->n_point ); 
+
 	return( 0 );
 }
 

From 2f8a279f2d3bd2ecc10c967080211a9fee69534e Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Thu, 12 Jan 2017 21:53:24 +0000
Subject: [PATCH 8/9] ooops, forgot convasep

---
 libvips/convolution/convasep.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libvips/convolution/convasep.c b/libvips/convolution/convasep.c
index 5f5209a6..5534bf52 100644
--- a/libvips/convolution/convasep.c
+++ b/libvips/convolution/convasep.c
@@ -877,6 +877,9 @@ vips_convasep_build( VipsObject *object )
 	convolution->out->Xoffset = 0;
 	convolution->out->Yoffset = 0;
 
+	vips_reorder_margin_hint( convolution->out,
+		convolution->M->Xsize * convolution->M->Ysize );
+
 	return( 0 );
 }
 

From dafa26435e8c5514433ac9e31459650ef56fe43d Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Fri, 13 Jan 2017 12:37:19 +0000
Subject: [PATCH 9/9] only use webp presets in lossy mode

it seems lossless and near-lossless modes have a separate preset system

see https://github.com/jcupitt/libvips/issues/578
---
 libvips/foreign/vips2webp.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/libvips/foreign/vips2webp.c b/libvips/foreign/vips2webp.c
index 5447c24c..a50d660b 100644
--- a/libvips/foreign/vips2webp.c
+++ b/libvips/foreign/vips2webp.c
@@ -237,7 +237,18 @@ write_webp( WebPPicture *pic, VipsImage *in,
 	WebPConfig config;
 	webp_import import;
 
-	if ( !WebPConfigPreset( &config, get_preset( preset ), Q ) ) {
+	if( !WebPConfigInit( &config ) ) {
+		vips_error( "vips2webp",
+			"%s", _( "config version error" ) );
+		return( -1 );
+	}
+
+	/* These presets are only for lossy compression. There seems to be
+	 * separate API for lossless or near-lossless, see
+	 * WebPConfigLosslessPreset().
+	 */
+	if( !(lossless || near_lossless) &&
+		!WebPConfigPreset( &config, get_preset( preset ), Q ) ) {
 		vips_error( "vips2webp", "%s", _( "config version error" ) );
 		return( -1 );
 	}