Merge branch 'master' into add-thumbnail-geometry

ChangeLog

@@ -19,8 +19,12 @@
   VIPS_LIBRARY_AGE
 - better support for bscale / bzero in fits images
 - deprecate vips_warn() / vips_info(); use g_warning() / g_info() instead
-- vipsthumbnail supports much fancier geometry strings
+- vipsthumbnail supports much fancier geometry strings, thanks tomasc
 - vips_thumbnail() has new @size option
+- 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

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

TODO

@@ -1,39 +1,3 @@
-- </>
-
-	convert k2.jpg -resize "100x100<" x.jpg
-
-		downsize, ie. factor < 1
-		does not resize
-
-	convert x.jpg -resize "200x200<" y.jpg
-
-		upsize, ie. factor > 1
-		resizes
-
-	convert k2.jpg -resize "100x100>" x.jpg
-
-		downsize, ie. factor < 1
-		resizes
-
-	convert x.jpg -resize "200x200>" y.jpg
-
-		upsize, ie. factor > 1
-		does not resize
-
-  so: < means only resize if input size is less than, > means only resize if
-  input size is > than
-
-  awkward to fit inside vipsthumbnail.c, since we'd have to copy/paste all the
-  resize calcs
-
-  have to add another param to thumbnail ... up or down, only up, only down
-
-
-
-- 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: 

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)

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_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 );
-	}
 	p[i] = NULL;
 	q = (VipsPel *) VIPS_REGION_ADDR( or, r->left, r->top );
 

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" ); 
 

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 );
 

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 ) ) 

libvips/convolution/conv.c

@@ -113,6 +113,9 @@ vips_conv_build( VipsObject *object )
 		g_assert_not_reached();
 	}
 
+	vips_reorder_margin_hint( convolution->out, 
+		convolution->M->Xsize * convolution->M->Ysize );
+
 	return( 0 );
 }
 

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 );
 }
 

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 );
 }
 

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" ); 

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 );
 

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);
@@ -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 );
 	}

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 );
 }
 

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 );
 }
 

libvips/include/vips/image.h

@@ -506,6 +506,12 @@ 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 reorder.c, but really a function on image.
+ */
+int vips_reorder_prepare_many( VipsImage *image, 
+	struct _VipsRegion **regions, VipsRect *r );
+void vips_reorder_margin_hint( VipsImage *image, int margin );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/

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;
 
@@ -255,6 +250,9 @@ int vips__foreign_convert_saveable( VipsImage *in, VipsImage **ready,
 
 int vips__image_intize( VipsImage *in, VipsImage **out );
 
+void vips__reorder_init( void );
+int vips__reorder_set_input( VipsImage *image, VipsImage **in );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/

libvips/iofuncs/Makefile.am

@@ -1,6 +1,7 @@
 noinst_LTLIBRARIES = libiofuncs.la
 
 libiofuncs_la_SOURCES = \
+	reorder.c \
 	vipsmarshal.h \
 	vipsmarshal.c \
 	type.c \

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 );
 	}
 }
 

libvips/iofuncs/generate.c

@@ -379,12 +379,23 @@ 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] && 
 		vips__image_copy_fields_array( image, in ) )
 		return( -1 ); 
 
+	if( vips__reorder_set_input( image, in ) )
+		return( -1 ); 
+
 	return( 0 );
 }
 

libvips/iofuncs/init.c

@@ -364,6 +364,10 @@ vips_init( const char *argv0 )
 	 */
 	vips__cache_init();
 
+	/* Recomp reordering system.
+	 */
+	vips__reorder_init();
+
 	/* Start up packages.
 	 */
 	(void) vips_system_get_type();
@@ -614,6 +618,33 @@ 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 +683,13 @@ 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, 

libvips/iofuncs/reorder.c

@@ -0,0 +1,368 @@
+/* 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 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 )
+{
+	VipsReorder *reorder;
+		
+	if( (reorder = g_object_get_qdata( G_OBJECT( image ), 
+		vips__image_reorder_quark )) ) 
+		return( reorder );
+
+	reorder = VIPS_NEW( NULL, 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_full( G_OBJECT( image ), vips__image_reorder_quark, 
+		reorder, (GDestroyNotify) vips_reorder_destroy );
+
+	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;
+
+	/* 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 ) {
+		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] ) {
+					/* Should never happen.
+					 */
+					g_warning( "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( 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 && 
+		(!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( NULL, total + 1, VipsImage * );
+	reorder->cumulative_margin = VIPS_ARRAY( NULL, 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.
+				 */
+				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] );
+
+			}
+			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;
+			}
+		}
+	}
+
+	/* 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 );
+}
+
+/**
+ * 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_reorder_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 );
+}
+
+/**
+ * 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_margin_hint( 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" ); 
+}

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 );
 }
 

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 );
 }
 

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 );
 }
 

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 );
 }
 

libvips/resample/thumbnail.c

@@ -109,6 +109,30 @@ 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.
  */
@@ -483,6 +507,8 @@ 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;
 

tools/vipsthumbnail.c

@@ -361,6 +361,10 @@ 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.
 	 */