libvips/libvips/foreign/dzsave.c

/* save to deep zoom format
 *
 * 21/3/12
 * 	- from the tiff pyramid writer
 * 5/7/12 (thanks Alexander Koshman)
 * 	- make tiles down to 1x1 pixels 
 *	- oop make right-hand edge tiles 
 *	- improve overlap handling 
 * 7/7/12
 * 	- threaded write
 * 6/8/12 (thanks to Benjamin Gilbert for pointing out the errors)
 * 	- shrink down to a 1x1 pixel tile, even for very long and thin images
 * 	- round image size up on shrink
 * 	- write a .dzi file with the pyramid params
 * 	- default tile size and overlap now matches the openslide writer
 * 7/8/12 (thanks to Benjamin Gilbert again for more testing)
 * 	- reorganise the directory structure
 * 	- rename to basename and tile_size
 * 	- deprecate tile_width/_height and dirname 
 * 1/10/12
 * 	- did not write low pyramid layers for images with an odd number of
 * 	  scan lines (thanks Martin)
 * 2/10/12
 * 	- remove filename options from format string in .dzi (thanks Martin)
 * 3/10/12
 * 	- add zoomify and google maps output
 * 10/10/12
 * 	- add @background option
 * 1/11/12
 * 	- add @depth option
 * 21/1/13
 * 	- add @centre option
 * 26/2/13
 * 	- fix another corner case, thanks Martin
 * 29/5/13
 * 	- add --angle option
 * 19/6/13
 * 	- faster --centre logic, thanks Kacey
 * 18/4/14
 * 	- use libgsf for output so we can write to .zip etc. as well as the
 * 	  filesystem
 * 8/5/14
 * 	- set Type on strips so we can convert for save correctly, thanks
 * 	  philipgiuliani
 * 25/6/14
 * 	- stop on zip write >4gb, thanks bgilbert
 * 	- save metadata, see https://github.com/jcupitt/libvips/issues/137
 * 18/8/14
 * 	- use g_ date funcs, helps Windows
 * 14/2/15
 * 	- use vips_region_shrink()
 * 22/2/15
 * 	- use a better temp dir name for fs dz output
 * 8/8/15
 * 	- allow zip > 4gb if we have a recent libgsf
 * 9/9/15
 * 	- better overlap handling, thanks robclouth 
 * 24/11/15
 * 	- don't write almost blank tiles in google mode
 * 25/11/15
 * 	- always strip tile metadata 
 * 16/12/15
 * 	- fix overlap handling again, thanks erdmann
 * 8/6/16 Felix Bünemann
 * 	- add @compression option
 * 5/9/16
 * 	- more overlap changes to help gmaps mode
 * 8/9/16 Felix Bünemann
 * 	- move vips-properties out of subdir for gm and zoomify layouts
 * 15/10/16
 * 	- add dzsave_buffer
 * 11/11/16 Felix Bünemann
 * 	- better >4gb detection for zip output on older libgsfs
 * 18/8/17
 * 	- shut down the output earlier to flush zip output
 */

/*

    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

 */

/*

   This is difficult to test, there are so many options.

   It's failed in the past in these cases. These have layers with strips which 
   exactly align with image edges, or which have orphan scanlines which need 
   adding for the shrink. 

   1.	$ header test.v
	test.v: 14016x16448 uchar, 3 bands, srgb, openin VipsImage (0x11e7060)
	$ time vips dzsave test.v x --overlap 0

	Not all layers written.

   2.	$ header ~/Desktop/leicaimage.scn 
	/home/john/Desktop/leicaimage.scn: 4225x7905 uchar, 4 bands, rgb

	Not all layers written. 

    3.	$ header ~/leicatest1.scn 
	/home/john/leicatest1.scn: 11585x8449 uchar, 4 bands, rgb

	Not all layers written. 

   various combinations of odd and even tile-size and overlap need testing too.

	Overlap handling

   For deepzoom, tile-size == 254 and overlap == 1 means that edge tiles are 
   255 x 255 (though less at the bottom right) and non-edge tiles are 256 x 
   256. Tiles are positioned across the image in tile-size steps. This means 
   (confusingly) that two adjoining tiles will have two pixels in common.

   This has caused bugs in the past. 

 */

/*
#define DEBUG_VERBOSE
#define VIPS_DEBUG
#define DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <vips/vips.h>
#include <vips/internal.h>

#ifdef HAVE_GSF

#include <gsf/gsf.h>

/* Simple wrapper around libgsf.
 *
 * We need to be able to do scattered writes to structured files. So while
 * building a zip (for example) we need to be able to write to file/a/b.jpg,
 * then to file/c/d.jpg, then back to file/a/e.jpg. This is tricky with the
 * libgsf API which is happier doing writes in order.
 *
 * Put an API over libgsf to track refs to all directories and finish/close
 * them.
 */

/* Need to track the directory tree we are writing, with a ref for each
 * GsfOutput.
 */
typedef struct _VipsGsfDirectory { 
	struct _VipsGsfDirectory *parent;
	const char *name;

	/* List of child directories, if any.
	 */
	GSList *children;

	/* The GsfOutput we use for this object.
	 */
	GsfOutput *out;

	/* The root node holds the enclosing zip file or FS root ... finish
	 * this on cleanup.
	 */
        GsfOutput *container;

	/* Track number of files in tree and total length of filenames. We use
	 * this to estimate zip size to spot a >4gb write.
	 */
	size_t file_count;
	size_t filename_lengths;

	/* Set deflate compression level for zip container.
	 */
	gint deflate_level;

} VipsGsfDirectory; 

/* Close all dirs, non-NULL on error.
 */
static void *
vips_gsf_tree_close( VipsGsfDirectory *tree )
{
	vips_slist_map2( tree->children, 
		(VipsSListMap2Fn) vips_gsf_tree_close, NULL, NULL );

	if( tree->out ) {
		if( !gsf_output_is_closed( tree->out ) &&
			!gsf_output_close( tree->out ) ) {
			vips_error( "vips_gsf", 
				"%s", _( "unable to close stream" ) ); 
			return( tree );
		}

		g_object_unref( tree->out );
	}

	if( tree->container ) { 
		if( !gsf_output_is_closed( tree->container ) && 
			!gsf_output_close( tree->container ) ) {
			vips_error( "vips_gsf", 
				"%s", _( "unable to close stream" ) ); 
			return( tree );
		}

		g_object_unref( tree->container );
	}

	return( NULL ); 
}

/* Make a new tree root.
 */
static VipsGsfDirectory *
vips_gsf_tree_new( GsfOutput *out, gint deflate_level )
{
	VipsGsfDirectory *tree = g_new( VipsGsfDirectory, 1 );

	tree->parent = NULL;
	tree->name = NULL;
	tree->children = NULL;
	tree->out = out;
	tree->container = NULL;
	tree->file_count = 0;
	tree->filename_lengths = 0;
	tree->deflate_level = deflate_level;

	return( tree ); 
}

static void *
vips_gsf_child_by_name_sub( VipsGsfDirectory *dir, const char *name )
{
	if( strcmp( dir->name, name ) == 0 )
		return( dir );

	return( NULL ); 
}

/* Look up a child by name.
 */
static VipsGsfDirectory *
vips_gsf_child_by_name( VipsGsfDirectory *dir, const char *name )
{
	return( vips_slist_map2( dir->children, 
		(VipsSListMap2Fn) vips_gsf_child_by_name_sub, 
		(char *) name, NULL ) );
}

/* Make a new directory.
 */
static VipsGsfDirectory *
vips_gsf_dir_new( VipsGsfDirectory *parent, const char *name )
{
	VipsGsfDirectory *dir = g_new( VipsGsfDirectory, 1 );

	g_assert( !vips_gsf_child_by_name( parent, name ) ); 

	dir->parent = parent;
	dir->name = g_strdup( name );
	dir->children = NULL;
	dir->container = NULL;
	dir->file_count = 0;
	dir->filename_lengths = 0;
	dir->deflate_level = parent->deflate_level;

	if( GSF_IS_OUTFILE_ZIP( parent->out ) )
		dir->out = gsf_outfile_new_child_full( 
			(GsfOutfile *) parent->out, 
			name, TRUE,
			"compression-level", GSF_ZIP_STORED,
			NULL );
	else
		dir->out = gsf_outfile_new_child( 
			(GsfOutfile *) parent->out, 
			name, TRUE ); 

	g_assert( dir->out ); 

	parent->children = g_slist_prepend( parent->children, dir ); 

	return( dir ); 
}

/* Return a GsfOutput for writing to a path. Paths are object name first, then
 * path components with least-specific first, NULL-terminated. For example:
 *
 * GsfOutput *obj = vips_gsf_path( tree, "fred.jpg", "a", "b", NULL );
 *
 * Returns an obj you can use to write to a/b/fred.jpg. 
 *
 * You must write, close and unref obj.
 */
static GsfOutput *
vips_gsf_path( VipsGsfDirectory *tree, const char *name, ... )
{
	va_list ap;
	VipsGsfDirectory *dir;
	VipsGsfDirectory *child;
	char *dir_name;
	GsfOutput *obj;

	/* vips_gsf_path() always makes a new file, though it may add to an
	 * existing directory. Note the file, and note the length of the full
	 * path we are creating.
	 */
	tree->file_count += 1;
	tree->filename_lengths += strlen( tree->out->name ) + strlen( name ) + 1;

	dir = tree; 
	va_start( ap, name );
	while( (dir_name = va_arg( ap, char * )) ) {
		if( (child = vips_gsf_child_by_name( dir, dir_name )) )
			dir = child;
		else 
			dir = vips_gsf_dir_new( dir, dir_name );

		tree->filename_lengths += strlen( dir_name ) + 1;
	}
	va_end( ap );

	if( GSF_IS_OUTFILE_ZIP( dir->out ) ) {
		/* Confusingly, libgsf compression-level really means
		 * compression-method. They have a separate deflate-level 
		 * property for the deflate compression level.
		 */
		if( dir->deflate_level == 0 )
			obj = gsf_outfile_new_child_full(
				(GsfOutfile *) dir->out,
				name, FALSE,
				"compression-level", GSF_ZIP_STORED,
				NULL );
		else if( dir->deflate_level == -1 )
			obj = gsf_outfile_new_child_full(
				(GsfOutfile *) dir->out,
				name, FALSE,
				"compression-level", GSF_ZIP_DEFLATED,
				NULL );
		else
			obj = gsf_outfile_new_child_full(
				(GsfOutfile *) dir->out,
				name, FALSE,
				"compression-level", GSF_ZIP_DEFLATED,
				"deflate-level", dir->deflate_level,
				NULL );
	}
	else
		obj = gsf_outfile_new_child( (GsfOutfile *) dir->out,
			name, FALSE ); 

	return( obj ); 
}

typedef struct _VipsForeignSaveDz VipsForeignSaveDz;
typedef struct _Layer Layer;

/* A layer in the pyramid.
 */
struct _Layer {
	VipsForeignSaveDz *dz;

	/* The real size of the image. image->Xsize and image->Ysize are
	 * always even to make x2 shrink easy. The real image may be a 
	 * smaller, odd size, 
	 */
	int width;
	int height;

	/* Number of tiles across and down in this layer. Zoomify needs this
	 * to calculate the directory to put each tile in.
	 */
	int tiles_across;
	int tiles_down;

	/* The rect within width/height that contains real image, as opposed
	 * to background. In centre mode we can have large image borders.
	 */
	VipsRect real_pixels; 

	/* The image we build.
	 */
	VipsImage *image;

	/* The top of this strip of tiles.
	 */
	int y;

	/* The next line we write to in this strip. 
	 */
	int write_y;

	VipsRegion *strip;		/* The current strip of pixels */
	VipsRegion *copy;		/* Pixels we copy to the next strip */

	int sub;			/* Subsample factor for this layer */
	int n;				/* Layer number ... 0 for smallest */

	Layer *below;			/* Tiles go to here */
	Layer *above;			/* Tiles come from here */
};

struct _VipsForeignSaveDz {
	VipsForeignSave parent_object;

	char *suffix;
	int overlap;
	int tile_size;
	VipsForeignDzLayout layout;
	VipsForeignDzDepth depth;
	gboolean centre;
	gboolean properties;
	VipsAngle angle;
	VipsForeignDzContainer container; 
	int compression;

	/* Tile and overlap geometry. The members above are the parameters we
	 * accept, this nest set are the derived values which are actually 
	 * used in pyramid generation.
	 *
	 * Tiles have a base size. Imagine a square placed at the top left.
	 * This is the size of that square.
	 *
	 * Tiles have a margin. The square from tile_size is expanded outward 
	 * up/down/left/right by this amount. Parts going off the image are 
	 * clipped. 
	 *
	 * Each time we write a new tile, we step the position by tile_step
	 * pixels. 
	 *
	 * We need all three of tile_size, tile_margin and tile_step since
	 * deepzoom and google maps have different meanings for overlap and we
	 * want to be able to support both models.
	 *
	 * For deepzoom:
	 *
	 * 	tile_margin = overlap
	 * 	tile_step = tile_size
	 *
	 * For google maps:
	 *
	 * 	tile_margin = 0
	 *	tile_step = tile_size - overlap
	 */
	int tile_margin;
	int tile_step;

	Layer *layer;			/* x2 shrink pyr layer */

	/* Count zoomify tiles we write.
	 */
	int tile_count;

	/* The tree structure we are writing tiles to. Can be filesystem, a
	 * zipfile, etc. 
	 */
	VipsGsfDirectory *tree;

	/* The actual output object our zip (or whatever) is writing to.
	 */
	GsfOutput *out;

	/* The name to save as, eg. deepzoom tiles go into ${basename}_files.
	 * No suffix, no path at the start. 
	 */
	char *basename; 

	/* The directory we write the output to, or NULL for memory output. 
	 */
	char *dirname; 

	/* For DZ save, we have to write to a temp dir. Track the name here.
	 */
	char *tempdir;

	/* The root directory name ... $basename with perhaps some extra
	 * stuff, eg. $(basename)_files, etc.
	 */
	char *root_name; 

	/* @suffix, but without any options. So @suffix == ".jpg[Q=90]"
	 * becomes ".jpg".
	 */
	char *file_suffix;

	/* libgsf before 1.14.31 can't write zip files larger than 4gb. 
	 * Track bytes written here and try to guess when we'll go over.
	 */
	size_t bytes_written;

	/* save->background turned into a pixel that matches the image we are
	 * saving .. used to test for blank tiles.
	 */
	VipsPel *ink;

};

typedef VipsForeignSaveClass VipsForeignSaveDzClass;

G_DEFINE_ABSTRACT_TYPE( VipsForeignSaveDz, vips_foreign_save_dz, 
	VIPS_TYPE_FOREIGN_SAVE );

/* Free a pyramid.
 */
static void
layer_free( Layer *layer )
{
	VIPS_FREEF( g_object_unref, layer->strip );
	VIPS_FREEF( g_object_unref, layer->copy );
	VIPS_FREEF( g_object_unref, layer->image );

	VIPS_FREEF( layer_free, layer->below ); 
}

static void
vips_foreign_save_dz_dispose( GObject *gobject )
{
	VipsForeignSaveDz *dz = (VipsForeignSaveDz *) gobject;

	VIPS_FREEF( layer_free, dz->layer );
	VIPS_FREEF( vips_gsf_tree_close,  dz->tree );
	VIPS_FREEF( g_object_unref, dz->out );
	VIPS_FREE( dz->basename );
	VIPS_FREE( dz->dirname );
	VIPS_FREE( dz->tempdir );
	VIPS_FREE( dz->root_name );
	VIPS_FREE( dz->file_suffix );

	G_OBJECT_CLASS( vips_foreign_save_dz_parent_class )->
		dispose( gobject );
}

/* Build a pyramid. 
 *
 * width/height is the size of this layer, real_* the subsection of the layer
 * which is real pixels (as opposed to background). 
 */
static Layer *
pyramid_build( VipsForeignSaveDz *dz, Layer *above, 
	int width, int height, VipsRect *real_pixels )
{
	VipsForeignSave *save = VIPS_FOREIGN_SAVE( dz );
	Layer *layer = VIPS_NEW( dz, Layer );

	int right;
	int bottom;
	VipsRect strip;
	int limit; 

	layer->dz = dz;
	layer->width = width;
	layer->height = height;

	/* The 0 position of the right-most possible tile.
	 */
	right = VIPS_MAX( 0, width - dz->tile_margin - dz->tile_size ); 

	/* Tiles from that to the left edge will be spaced by tile step. The +1
	 * is the tile we subtracted above. 
	 */
	layer->tiles_across = ceil( (double) right / dz->tile_step ) + 1; 

	bottom = VIPS_MAX( 0, height - dz->tile_margin - dz->tile_size );
	layer->tiles_down = ceil( (double) bottom / dz->tile_step ) + 1;

	layer->real_pixels = *real_pixels; 

	layer->image = NULL;
	layer->strip = NULL;
	layer->copy = NULL;

	if( !above )
		/* Top of pyramid.
		 */
		layer->sub = 1;	
	else
		layer->sub = above->sub * 2;

	layer->below = NULL;
	layer->above = above;

	/* We round the image size up to an even number to make x2 shrink
	 * easy.
	 */
	layer->image = vips_image_new();
	if( vips_image_pipelinev( layer->image, 
		VIPS_DEMAND_STYLE_ANY, save->ready, NULL ) ) {
		layer_free( layer );
		return( NULL );
	}
	layer->image->Xsize = width + (width & 1);
	layer->image->Ysize = height + (height & 1);

	layer->strip = vips_region_new( layer->image );
	layer->copy = vips_region_new( layer->image );

	/* The regions will get used in the bg thread callback, so make sure
	 * we don't own them.
	 */
	vips__region_no_ownership( layer->strip );
	vips__region_no_ownership( layer->copy );

	/* Build a line of tiles here. 
	 *
	 * Expand the strip if necessary to make sure we have an even 
	 * number of lines. 
	 *
	 * This is just the height of the first row of tiles, so only add 1*
	 * tile_margin.
	 */
	layer->y = 0;
	layer->write_y = 0;
	strip.left = 0;
	strip.top = 0;
	strip.width = layer->image->Xsize;
	strip.height = dz->tile_size + dz->tile_margin;
	if( (strip.height & 1) == 1 )
		strip.height += 1;
	if( vips_region_buffer( layer->strip, &strip ) ) {
		layer_free( layer );
		return( NULL );
	}

	switch( dz->depth ) {
	case VIPS_FOREIGN_DZ_DEPTH_ONEPIXEL:
		limit = 1;
		break;

	case VIPS_FOREIGN_DZ_DEPTH_ONETILE:
		limit = dz->tile_size;
		break;

	case VIPS_FOREIGN_DZ_DEPTH_ONE:
		limit = VIPS_MAX( width, height );
		break;

	default:
		g_assert_not_reached();

		/* Stop compiler warnings.
		 */
		limit = 1;
	}

	if( width > limit || 
		height > limit ) {
		/* Round up, so eg. a 5 pixel wide image becomes 3 a layer
		 * down.
		 *
		 * For the rect, round left/top down, round bottom/right up,
		 * so we get all possible pixels. 
		 */
		VipsRect halfrect;

		halfrect.left = real_pixels->left / 2;
		halfrect.top = real_pixels->top / 2;
		halfrect.width = (VIPS_RECT_RIGHT( real_pixels ) + 1) / 2 - 
			halfrect.left;
		halfrect.height = (VIPS_RECT_BOTTOM( real_pixels ) + 1) / 2 - 
			halfrect.top;

		if( !(layer->below = pyramid_build( dz, layer, 
			(width + 1) / 2, (height + 1) / 2,
			&halfrect )) ) { 
			layer_free( layer );
			return( NULL );
		}
		layer->n = layer->below->n + 1;
	}
	else
		layer->n = 0;

#ifdef DEBUG
	printf( "pyramid_build:\n" );
	printf( "\tn = %d\n", layer->n );
	printf( "\twidth = %d, height = %d\n", width, height );
	printf( "\tXsize = %d, Ysize = %d\n", 
		layer->image->Xsize, layer->image->Ysize );
	printf( "\ttiles_across = %d, tiles_down = %d\n", 
		layer->tiles_across, layer->tiles_down ); 
	printf( "\treal_pixels.left = %d, real_pixels.top = %d\n", 
		real_pixels->left, real_pixels->top ); 
	printf( "\treal_pixels.width = %d, real_pixels.height = %d\n", 
		real_pixels->width, real_pixels->height ); 
#endif

	return( layer );
}

static int
write_dzi( VipsForeignSaveDz *dz )
{
	GsfOutput *out;
	char buf[VIPS_PATH_MAX];
	char *p;

	vips_snprintf( buf, VIPS_PATH_MAX, "%s.dzi", dz->basename );
	out = vips_gsf_path( dz->tree, buf, NULL ); 

	vips_snprintf( buf, VIPS_PATH_MAX, "%s", dz->suffix + 1 );
	if( (p = (char *) vips__find_rightmost_brackets( buf )) )
		*p = '\0';

	gsf_output_printf( out, "<?xml "
		"version=\"1.0\" encoding=\"UTF-8\"?>\n" ); 
	gsf_output_printf( out, "<Image "
		"xmlns=\"http://schemas.microsoft.com/deepzoom/2008\"\n" );
	gsf_output_printf( out, "  Format=\"%s\"\n", buf );
	gsf_output_printf( out, "  Overlap=\"%d\"\n", dz->overlap );
	gsf_output_printf( out, "  TileSize=\"%d\"\n", dz->tile_size );
	gsf_output_printf( out, "  >\n" ); 
	gsf_output_printf( out, "  <Size \n" );
	gsf_output_printf( out, "    Height=\"%d\"\n", dz->layer->height );
	gsf_output_printf( out, "    Width=\"%d\"\n", dz->layer->width );
	gsf_output_printf( out, "  />\n" ); 
	gsf_output_printf( out, "</Image>\n" );

	(void) gsf_output_close( out );
	g_object_unref( out );

	return( 0 );
}

static int
write_properties( VipsForeignSaveDz *dz )
{
	GsfOutput *out;

	out = vips_gsf_path( dz->tree, "ImageProperties.xml", NULL ); 

	gsf_output_printf( out, "<IMAGE_PROPERTIES "
		"WIDTH=\"%d\" HEIGHT=\"%d\" NUMTILES=\"%d\" "
		"NUMIMAGES=\"1\" VERSION=\"1.8\" TILESIZE=\"%d\" />\n",
		dz->layer->width,
		dz->layer->height,
		dz->tile_count,
		dz->tile_size );

	(void) gsf_output_close( out );
	g_object_unref( out );

	return( 0 );
}

static int
write_blank( VipsForeignSaveDz *dz )
{
	VipsForeignSave *save = (VipsForeignSave *) dz;

	VipsImage *x, *t;
	int n;
	VipsArea *ones;
	double *d;
	double *bg;
	int i;
	void *buf;
	size_t len;
	GsfOutput *out; 

	/* Number of bands we will end up making. We need to set this in
	 * vips_black() to make sure we set Type correctly, otherwise we can
	 * try saving a B_W image as PNG, with disasterous results.
	 */
	bg = (double *) vips_area_get_data( VIPS_AREA( save->background ), 
		NULL, &n, NULL, NULL );

	if( vips_black( &x, dz->tile_size, dz->tile_size, "bands", n, NULL ) ) 
		return( -1 );

	ones = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n );
	d = (double *) vips_area_get_data( ones, NULL, NULL, NULL, NULL );
	for( i = 0; i < n; i++ )
		d[i] = 1.0; 

	if( vips_linear( x, &t, d, bg, n, NULL ) ) {
		vips_area_unref( ones );
		g_object_unref( x );
		return( -1 );
	}
	vips_area_unref( ones );
	g_object_unref( x );
	x = t;

	if( vips_pngsave_buffer( x, &buf, &len, NULL ) ) {
		g_object_unref( x );
		return( -1 );
	}
	g_object_unref( x );

	out = vips_gsf_path( dz->tree, "blank.png", NULL ); 
	gsf_output_write( out, len, buf );
	gsf_output_close( out );
	g_object_unref( out );

	g_free( buf );

	return( 0 );
}

static int
write_vips_meta( VipsForeignSaveDz *dz )
{
	VipsForeignSave *save = (VipsForeignSave *) dz;

	char *dump;
	GsfOutput *out;

	if( !(dump = vips__xml_properties( save->ready )) )
                return( -1 );

	/* For deepzom the props must go inside the ${name}_files subdir, for
	 * gm and zoomify it can sit in the main folder.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ )
		out = vips_gsf_path( dz->tree, 
			"vips-properties.xml", dz->root_name, NULL );
	else
		out = vips_gsf_path( dz->tree, "vips-properties.xml", NULL );

	gsf_output_write( out, strlen( dump ), (guchar *) dump ); 
	(void) gsf_output_close( out );
	g_object_unref( out );

	g_free( dump );

	return( 0 );
}

/* Our state during a threaded write of a strip.
 */
typedef struct _Strip {
	Layer *layer; 

	VipsImage *image;

	/* Allocate the next tile on this boundary. 
	 */
	int x;
} Strip;

static void
strip_free( Strip *strip )
{
	g_object_unref( strip->image );
}

static void
strip_init( Strip *strip, Layer *layer )
{
	VipsForeignSaveDz *dz = layer->dz;

	VipsRect line, image;

	strip->layer = layer;
	strip->image = NULL;
	strip->x = 0;

	/* The image we wrap around our pixel buffer must be the full width,
	 * including any rounding up, since we must have contiguous pixels.
	 * We can trim the height down though.
	 *
	 * When we loop across the strip writing tiles we have to look out for
	 * the smaller width.
	 */
	image.left = 0;
	image.top = 0;
	image.width = layer->image->Xsize;
	image.height = layer->height;

	line.left = 0;
	line.top = layer->y;
	line.width = image.width;
	line.height = dz->tile_size;
	vips_rect_marginadjust( &line, dz->tile_margin );

	vips_rect_intersectrect( &image, &line, &line );

	if( !(strip->image = vips_image_new_from_memory( 
		VIPS_REGION_ADDR( layer->strip, 0, line.top ),
		VIPS_IMAGE_SIZEOF_LINE( layer->image ) * line.height,
		line.width, line.height, 
		layer->image->Bands, layer->image->BandFmt )) ) {
		strip_free( strip );
		return;
	}

	/* Type needs to be set so we know how to convert for save correctly.
	 */
	strip->image->Type = layer->image->Type;
}

static int
strip_allocate( VipsThreadState *state, void *a, gboolean *stop )
{
	Strip *strip = (Strip *) a;
	Layer *layer = strip->layer;
	VipsForeignSaveDz *dz = layer->dz;

	VipsRect image;

#ifdef DEBUG_VERBOSE
	printf( "strip_allocate\n" );
#endif /*DEBUG_VERBOSE*/

	/* We can't test for allocated area empty, since it might just have
	 * bits of the left-hand overlap in and no new pixels. Safest to count
	 * tiles across.
	 */
	if( strip->x / dz->tile_step >= layer->tiles_across ) {
		*stop = TRUE;
#ifdef DEBUG_VERBOSE
		printf( "strip_allocate: done\n" );
#endif /*DEBUG_VERBOSE*/

		return( 0 );
	}

	image.left = 0;
	image.top = 0;
	image.width = layer->width;
	image.height = layer->height;

	/* Position this tile.
	 */
	state->pos.left = strip->x;
	state->pos.top = layer->y;
	state->pos.width = dz->tile_size;
	state->pos.height = dz->tile_size;
	vips_rect_marginadjust( &state->pos, dz->tile_margin );

	vips_rect_intersectrect( &image, &state->pos, &state->pos );
	state->x = strip->x;
	state->y = layer->y;

	strip->x += dz->tile_step;

	return( 0 );
}

/* Make an output object for a tile in the current layout.
 */
static GsfOutput *
tile_name( Layer *layer, int x, int y )
{
	VipsForeignSaveDz *dz = layer->dz;

	GsfOutput *out; 
	char name[VIPS_PATH_MAX];
	char dirname[VIPS_PATH_MAX];
	char dirname2[VIPS_PATH_MAX];
	Layer *p;
	int n;

	switch( dz->layout ) {
	case VIPS_FOREIGN_DZ_LAYOUT_DZ:
		vips_snprintf( dirname, VIPS_PATH_MAX, "%d", layer->n );
		vips_snprintf( name, VIPS_PATH_MAX, 
			"%d_%d%s", x, y, dz->file_suffix );

		out = vips_gsf_path( dz->tree, name, 
			dz->root_name, dirname, NULL );

		break;

	case VIPS_FOREIGN_DZ_LAYOUT_ZOOMIFY:
		/* We need to work out the tile number so we can calculate the
		 * directory to put this tile in.
		 *
		 * Tiles are numbered from 0 for the most-zoomed-out tile. 
		 */
		n = 0;

		/* Count all tiles in layers below this one. 
		 */
		for( p = layer->below; p; p = p->below )
			n += p->tiles_across * p->tiles_down;

		/* And count tiles so far in this layer.
		 */
		n += y * layer->tiles_across + x;

		vips_snprintf( dirname, VIPS_PATH_MAX, "TileGroup%d", n / 256 );
		vips_snprintf( name, VIPS_PATH_MAX, 
			"%d-%d-%d%s", layer->n, x, y, dz->file_suffix );

		/* Used at the end in ImageProperties.xml
		 */
		dz->tile_count += 1;

		out = vips_gsf_path( dz->tree, name, dirname, NULL );

		break;

	case VIPS_FOREIGN_DZ_LAYOUT_GOOGLE:
		vips_snprintf( dirname, VIPS_PATH_MAX, "%d", layer->n );
		vips_snprintf( dirname2, VIPS_PATH_MAX, "%d", y );
		vips_snprintf( name, VIPS_PATH_MAX, 
			"%d%s", x, dz->file_suffix );

		out = vips_gsf_path( dz->tree, name, dirname, dirname2, NULL );

		break;

	default:
		g_assert_not_reached();

		/* Stop compiler warnings.
		 */
		out = NULL;
	}

#ifdef DEBUG_VERBOSE
	printf( "tile_name: writing to %s\n", name );
#endif /*DEBUG_VERBOSE*/

	return( out );
}

/* Test for tile equal to background colour. In google maps mode, we skip
 * blank background tiles. 
 *
 * Don't use exactly equality, since compression artefacts or noise can upset
 * this.
 */
static gboolean
tile_equal( VipsImage *image, VipsPel * restrict ink )
{
	const int bytes = VIPS_IMAGE_SIZEOF_PEL( image );

	VipsRect rect;
	VipsRegion *region;
	int x, y, b;

	region = vips_region_new( image ); 

	/* We know @image is part of a memory buffer, so this will be quick.
	 */
	rect.left = 0;
	rect.top = 0;
	rect.width = image->Xsize;
	rect.height = image->Ysize;
	if( vips_region_prepare( region, &rect ) ) {
		g_object_unref( region );
		return( FALSE ); 
	}

	for( y = 0; y < image->Ysize; y++ ) {
		VipsPel * restrict p = VIPS_REGION_ADDR( region, 0, y ); 

		for( x = 0; x < image->Xsize; x++ ) {
			for( b = 0; b < bytes; b++ ) 
				if( VIPS_ABS( p[b] - ink[b] ) > 5 ) {
					g_object_unref( region );
					return( FALSE ); 
				}

			p += bytes;
		}
	}

	g_object_unref( region );

	return( TRUE );
}

#define VIPS_ZIP_FIXED_LH_SIZE (30 + 29)
#define VIPS_ZIP_FIXED_CD_SIZE (46 + 9)
#define VIPS_ZIP_EOCD_SIZE 22

#ifndef HAVE_GSF_ZIP64
static size_t
estimate_zip_size( VipsForeignSaveDz *dz )
{
	size_t estimated_zip_size = dz->bytes_written + 
		dz->tree->file_count * VIPS_ZIP_FIXED_LH_SIZE + 
		dz->tree->filename_lengths + 
		dz->tree->file_count * VIPS_ZIP_FIXED_CD_SIZE + 
		dz->tree->filename_lengths + 
		VIPS_ZIP_EOCD_SIZE;

#ifdef DEBUG_VERBOSE
	printf( "estimate_zip_size: %zd\n", estimated_zip_size );
#endif /*DEBUG_VERBOSE*/

	return( estimated_zip_size );
}
#endif /*HAVE_GSF_ZIP64*/

static int
strip_work( VipsThreadState *state, void *a )
{
	Strip *strip = (Strip *) a;
	Layer *layer = strip->layer;
	VipsForeignSaveDz *dz = layer->dz;
	VipsForeignSave *save = (VipsForeignSave *) dz;
	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( dz ); 

	VipsImage *x;
	VipsImage *t;
	void *buf;
	size_t len;
	GsfOutput *out; 
	gboolean status;

#ifdef DEBUG_VERBOSE
	printf( "strip_work\n" );
#endif /*DEBUG_VERBOSE*/

	/* If we are centering we may be outside the real pixels. Skip in 
	 * this case, and the viewer will display blank.png for us. 
	 */
	if( dz->centre ) {
		VipsRect tile; 

		tile.left = state->x;
		tile.top = state->y;
		tile.width = dz->tile_size;
		tile.height = dz->tile_size;
		vips_rect_intersectrect( &tile, &layer->real_pixels, &tile );
		if( vips_rect_isempty( &tile ) ) {
#ifdef DEBUG_VERBOSE
			printf( "strip_work: skipping tile %d x %d\n", 
				state->x / dz->tile_size, 
				state->y / dz->tile_size ); 
#endif /*DEBUG_VERBOSE*/

			return( 0 ); 
		}
	}

#ifdef DEBUG
	vips_object_sanity( VIPS_OBJECT( strip->image ) );
#endif /*DEBUG*/

	/* Extract relative to the strip top-left corner.
	 */
	if( vips_extract_area( strip->image, &x, 
		state->pos.left, 0, 
		state->pos.width, state->pos.height, NULL ) ) 
		return( -1 );

	/* If we are writing a google map pyramid and the tile is equal to the 
	 * background, don't save. The viewer will display blank.png for us.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE &&
		tile_equal( x, dz->ink ) ) { 
		g_object_unref( x );

#ifdef DEBUG_VERBOSE
		printf( "strip_work: skipping blank tile %d x %d\n", 
			state->x / dz->tile_size, 
			state->y / dz->tile_size ); 
#endif /*DEBUG_VERBOSE*/

		return( 0 ); 
	}

	/* Google tiles need to be padded up to tilesize.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE ) {
		if( vips_embed( x, &t, 0, 0, dz->tile_size, dz->tile_size,
			"background", save->background,
			NULL ) ) {
			g_object_unref( x );
			return( -1 );
		}
		g_object_unref( x );

		x = t;
	}

	/* Hopefully, no one will want the same metadata on all the tiles.
	 * Strip them.
	 */
	vips_image_set_int( x, "hide-progress", 1 );
	if( vips_image_write_to_buffer( x, dz->suffix, &buf, &len, 
		"strip", TRUE, 
		NULL ) ) {
		g_object_unref( x );
		return( -1 );
	}
	g_object_unref( x );

	/* gsf doesn't like more than one write active at once.
	 */
	g_mutex_lock( vips__global_lock );

	out = tile_name( layer, 
		state->x / dz->tile_step, state->y / dz->tile_step );

	status = gsf_output_write( out, len, buf );
	dz->bytes_written += len;

	gsf_output_close( out );
	g_object_unref( out );

	g_free( buf );

	if( !status ) {
		g_mutex_unlock( vips__global_lock );

		vips_error( class->nickname,
			"%s", gsf_output_error( out )->message ); 
		return( -1 ); 
	}

#ifndef HAVE_GSF_ZIP64
	if( dz->container == VIPS_FOREIGN_DZ_CONTAINER_ZIP ) { 
		/* Leave 3 entry headroom for blank.png and metadata files. 
		 */
		if( dz->tree->file_count + 3 >= (unsigned int) USHRT_MAX ) {
			g_mutex_unlock( vips__global_lock );

			vips_error( class->nickname,
				"%s", _( "too many files in zip" ) ); 
			return( -1 );
		}

		/* Leave 16k headroom for blank.png and metadata files. 
		 */
		if( estimate_zip_size( dz ) > (size_t) UINT_MAX - 16384) {
			g_mutex_unlock( vips__global_lock );

			vips_error( class->nickname,
				"%s", _( "output file too large" ) ); 
			return( -1 ); 
		}
	}
#endif /*HAVE_GSF_ZIP64*/

	g_mutex_unlock( vips__global_lock );

#ifdef DEBUG_VERBOSE
	printf( "strip_work: success\n" );
#endif /*DEBUG_VERBOSE*/

	return( 0 );
}

/* Write a line of tiles with a threadpool. 
 */
static int
strip_save( Layer *layer )
{
	Strip strip;

#ifdef DEBUG
	printf( "strip_save: n = %d, y = %d\n", layer->n, layer->y );
#endif /*DEBUG*/

	strip_init( &strip, layer );
	if( vips_threadpool_run( strip.image, 
		vips_thread_state_new, strip_allocate, strip_work, NULL, 
		&strip ) ) {
		strip_free( &strip );
		return( -1 );
	}
	strip_free( &strip );

#ifdef DEBUG
	printf( "strip_save: success\n" ); 
#endif /*DEBUG*/

	return( 0 );
}

/* A strip has filled, but the rightmost column and the bottom-most row may
 * not have been if we've rounded the size up.
 *
 * Fill them, if necessary, by copying the previous row/column.
 */
static void
layer_generate_extras( Layer *layer )
{
	VipsRegion *strip = layer->strip;

	/* We only work for full-width strips.
	 */
	g_assert( strip->valid.width == layer->image->Xsize );

	if( layer->width < layer->image->Xsize ) {
		int ps = VIPS_IMAGE_SIZEOF_PEL( strip->im );

		int b, y;

		/* Need to add a right-most column.
		 */
		for( y = 0; y < strip->valid.height; y++ ) {
			VipsPel *p = VIPS_REGION_ADDR( strip, 
				layer->width - 1, strip->valid.top + y );
			VipsPel *q = p + ps;

			for( b = 0; b < ps; b++ )
				q[b] = p[b];
		}
	}

	if( layer->height < layer->image->Ysize ) {
		VipsRect last;

		/* The last two lines of the image.
		 */
		last.left = 0;
		last.top = layer->image->Ysize - 2;
		last.width = layer->image->Xsize;
		last.height = 2;
	
		/* Do we have them both? Fill the last with the next-to-last.
		 */
		vips_rect_intersectrect( &last, &strip->valid, &last );
		if( last.height == 2 ) {
			last.height = 1;

			vips_region_copy( strip, strip, &last, 
				0, last.top + 1 );
		}
	}
}

static int strip_arrived( Layer *layer );

/* Shrink what pixels we can from this strip into the layer below. If the
 * strip below fills, recurse.
 */
static int
strip_shrink( Layer *layer )
{
	Layer *below = layer->below;
	VipsRegion *from = layer->strip;
	VipsRegion *to = below->strip;

	VipsRect target;
	VipsRect source;

#ifdef DEBUG
	printf( "strip_shrink: %d lines in layer %d to layer %d\n", 
		from->valid.height, layer->n, below->n ); 
#endif/*DEBUG*/

	/* We may have an extra column of pixels on the right or
	 * bottom that need filling: generate them.
	 */
	layer_generate_extras( layer );

	/* Our pixels might cross a strip boundary in the layer below, so we
	 * have to write repeatedly until we run out of pixels.
	 */
	for(;;) {
		/* The pixels the layer below needs.
		 */
		target.left = 0;
		target.top = below->write_y;
		target.width = below->image->Xsize;
		target.height = to->valid.height;
		vips_rect_intersectrect( &target, &to->valid, &target );

		/* Those pixels need this area of this layer. 
		 */
		source.left = target.left * 2;
		source.top = target.top * 2;
		source.width = target.width * 2;
		source.height = target.height * 2;

		/* Of which we have these available.
		 */
		vips_rect_intersectrect( &source, &from->valid, &source );

		/* So these are the pixels in the layer below we can provide.
		 */
		target.left = source.left / 2;
		target.top = source.top / 2;
		target.width = source.width / 2;
		target.height = source.height / 2;

		/* None? All done.
		 */
		if( vips_rect_isempty( &target ) ) 
			break;

		(void) vips_region_shrink( from, to, &target );

		below->write_y += target.height;

		/* If we've filled the strip below, let it know.
		 * We can either fill the region, if it's somewhere half-way
		 * down the image, or, if it's at the bottom, get to the last
		 * real line of pixels.
		 */
		if( below->write_y == VIPS_RECT_BOTTOM( &to->valid ) ||
			below->write_y == below->height ) {
			if( strip_arrived( below ) )
				return( -1 );
		}
	}

	return( 0 );
}

/* A new strip has arrived! The strip has enough pixels in to write a line of 
 * tiles. 
 *
 * - write a line of tiles
 * - shrink what we can to the layer below
 * - move our strip down by the tile step
 * - copy the overlap with the previous strip
 */
static int
strip_arrived( Layer *layer )
{
	VipsForeignSaveDz *dz = layer->dz;

	VipsRect new_strip;
	VipsRect overlap;
	VipsRect image_area;

#ifdef DEBUG
	printf( "strip_arrived: layer %d, strip at %d, height %d\n", 
		layer->n, layer->y, layer->strip->valid.height ); 
#endif/*DEBUG*/

	if( strip_save( layer ) )
		return( -1 );

	if( layer->below &&
		strip_shrink( layer ) )
		return( -1 );

	/* Position our strip down the image.  
	 *
	 * Expand the strip if necessary to make sure we have an even 
	 * number of lines. 
	 */
	layer->y += dz->tile_step;
	new_strip.left = 0;
	new_strip.top = layer->y - dz->tile_margin;
	new_strip.width = layer->image->Xsize;
	new_strip.height = dz->tile_size + 2 * dz->tile_margin;

	image_area.left = 0;
	image_area.top = 0;
	image_area.width = layer->image->Xsize;
	image_area.height = layer->image->Ysize;
	vips_rect_intersectrect( &new_strip, &image_area, &new_strip ); 

	if( (new_strip.height & 1) == 1 )
		new_strip.height += 1;

	/* We may exactly hit the bottom of the real image (ie. before borders
	 * have been possibly expanded by 1 pixel). In this case, we'll not 
	 * be able to do the expansion in layer_generate_extras(), since the 
	 * region won't be large enough, and we'll not get another chance 
	 * since this is the bottom. 
	 *
	 * Add another scanline if this has happened.
	 */
	if( VIPS_RECT_BOTTOM( &new_strip ) == layer->height )
		new_strip.height = layer->image->Ysize - new_strip.top;

	/* What pixels that we will need do we already have? Save them in 
	 * overlap.
	 */
	vips_rect_intersectrect( &new_strip, &layer->strip->valid, &overlap );
	if( !vips_rect_isempty( &overlap ) ) {
		if( vips_region_buffer( layer->copy, &overlap ) )
			return( -1 );
		vips_region_copy( layer->strip, layer->copy, 
			&overlap, overlap.left, overlap.top );
	}

	if( !vips_rect_isempty( &new_strip ) ) {
		if( vips_region_buffer( layer->strip, &new_strip ) )
			return( -1 );

		/* And copy back again.
		 */
		if( !vips_rect_isempty( &overlap ) ) 
			vips_region_copy( layer->copy, layer->strip, 
				&overlap, overlap.left, overlap.top );
	}

	return( 0 );
}

/* Another strip of image pixels from vips_sink_disc(). Write into the top
 * pyramid layer. 
 */
static int
pyramid_strip( VipsRegion *region, VipsRect *area, void *a )
{
	VipsForeignSaveDz *dz = (VipsForeignSaveDz *) a;
	Layer *layer = dz->layer;

#ifdef DEBUG
	printf( "pyramid_strip: strip at %d, height %d\n", 
		area->top, area->height );
#endif/*DEBUG*/

	for(;;) {
		VipsRect *to = &layer->strip->valid;
		VipsRect target;

		/* The bit of strip that needs filling.
		 */
		target.left = 0;
		target.top = layer->write_y;
		target.width = layer->image->Xsize;
		target.height = to->height;
		vips_rect_intersectrect( &target, to, &target );

		/* Clip against what we have available.
		 */
		vips_rect_intersectrect( &target, area, &target );

		/* Are we empty? All done.
		 */
		if( vips_rect_isempty( &target ) ) 
			break;

		/* And copy those pixels in.
		 *
		 * FIXME: If the strip fits inside the region we've just 
		 * received, we could skip the copy. Will this happen very
		 * often? Unclear.
		 */
		vips_region_copy( region, layer->strip, 
			&target, target.left, target.top );

		layer->write_y += target.height;

		/* We can either fill the strip, if it's somewhere half-way
		 * down the image, or, if it's at the bottom, get to the last
		 * real line of pixels.
		 */
		if( layer->write_y == VIPS_RECT_BOTTOM( to ) ||
			layer->write_y == layer->height ) {
			if( strip_arrived( layer ) ) 
				return( -1 );
		}
	}

	return( 0 );
}

static int
vips_foreign_save_dz_build( VipsObject *object )
{
	VipsForeignSave *save = (VipsForeignSave *) object;
	VipsForeignSaveDz *dz = (VipsForeignSaveDz *) object;
	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( dz ); 
	VipsRect real_pixels; 

	/* Google and zoomify default to zero overlap, ".jpg".
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_ZOOMIFY ||
		dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE ) {
		if( !vips_object_argument_isset( object, "overlap" ) )
			dz->overlap = 0;
		if( !vips_object_argument_isset( object, "suffix" ) )
			VIPS_SETSTR( dz->suffix, ".jpg" );
	}

	/* Google and zoomify default to 256 pixel tiles.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_ZOOMIFY ||
		dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE ) {
		if( !vips_object_argument_isset( object, "tile_size" ) )
			dz->tile_size = 256;
	}

	/* Our tile layout.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ ) { 
		dz->tile_margin = dz->overlap;
		dz->tile_step = dz->tile_size; 
	}
	else {
		dz->tile_margin = 0;
		dz->tile_step = dz->tile_size - dz->overlap;
	}

	if( dz->tile_step <= 0 ) {
		vips_error( "dzsave", "%s", _( "overlap too large" ) );
		return( -1 );
	}

	/* Default to white background. vips_foreign_save_init() defaults to
	 * black. 
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE &&
		!vips_object_argument_isset( object, "background" ) ) {
		VipsArrayDouble *background; 

		/* Using g_object_set() to set an input param in build will
		 * change the hash and confuse caching, but we don't cache
		 * savers, so it's fine.
		 */
		background = vips_array_double_newv( 1, 255.0 );
		g_object_set( object, "background", background, NULL );
		vips_area_unref( VIPS_AREA( background ) ); 
	}

	/* DeepZoom stops at 1x1 pixels, others when the image fits within a
	 * tile.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ ) {
		if( !vips_object_argument_isset( object, "depth" ) )
			dz->depth = VIPS_FOREIGN_DZ_DEPTH_ONEPIXEL;
	}
	else
		if( !vips_object_argument_isset( object, "depth" ) )
			dz->depth = VIPS_FOREIGN_DZ_DEPTH_ONETILE;

	if( VIPS_OBJECT_CLASS( vips_foreign_save_dz_parent_class )->
		build( object ) )
		return( -1 );

	/* Optional rotate.
	 */
{
	VipsImage *z;

	if( vips_rot( save->ready, &z, dz->angle, NULL ) )
		return( -1 );

	VIPS_UNREF( save->ready );
	save->ready = z;
}

	/* We use ink in google mode to check for blank tiles.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE ) {
		if( !(dz->ink = vips__vector_to_ink( 
			class->nickname, save->ready,
			VIPS_AREA( save->background )->data, NULL, 
			VIPS_AREA( save->background )->n )) )
			return( -1 );
	}

	/* The real pixels we have from our input. This is about to get
	 * expanded with background. 
	 */
	real_pixels.left = 0;
	real_pixels.top = 0;
	real_pixels.width = save->ready->Xsize;
	real_pixels.height = save->ready->Ysize;

	/* For centred images, imagine shrinking so that the image fits in a
	 * single tile, centering in that tile, then expanding back again.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE &&
		dz->centre ) {
		VipsImage *z;
		Layer *layer;
		int n_layers;
		int size;

		if( !(layer = pyramid_build( dz, NULL, 
			save->ready->Xsize, save->ready->Ysize,
			&real_pixels )) )
			return( -1 );
		n_layers = layer->n;
		/* This would cause interesting problems.
		 */
		g_assert( n_layers < 30 );
		layer_free( layer );
		size = dz->tile_size * (1 << n_layers);

		real_pixels.left = (size - save->ready->Xsize) / 2;
		real_pixels.top = (size - save->ready->Ysize) / 2;

		if( vips_embed( save->ready, &z, 
			real_pixels.left, real_pixels.top,
			size, size,
			"background", save->background,
			NULL ) ) 
			return( -1 );

		VIPS_UNREF( save->ready );
		save->ready = z;

#ifdef DEBUG
		printf( "centre: centring within a %d x %d image\n", 
			size, size );
#endif

	}

#ifdef DEBUG
	printf( "vips_foreign_save_dz_build: tile_size == %d\n", 
		dz->tile_size );
	printf( "vips_foreign_save_dz_build: overlap == %d\n", 
		dz->overlap );
	printf( "vips_foreign_save_dz_build: tile_margin == %d\n", 
		dz->tile_margin );
	printf( "vips_foreign_save_dz_build: tile_step == %d\n", 
		dz->tile_step );
#endif

	/* Build the skeleton of the image pyramid.
	 */
	if( !(dz->layer = pyramid_build( dz, NULL, 
		save->ready->Xsize, save->ready->Ysize, &real_pixels )) )
		return( -1 );

	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ )
		dz->root_name = g_strdup_printf( "%s_files", dz->basename );
	else
		dz->root_name = g_strdup( dz->basename );

	/* Drop any options from @suffix.
	 */
{
	char filename[VIPS_PATH_MAX];
	char option_string[VIPS_PATH_MAX];

	vips__filename_split8( dz->suffix, filename, option_string );
	dz->file_suffix = g_strdup( filename ); 
}

	/* If we will be renaming our temp dir to an existing directory or
	 * file, stop now. See vips_rename() use below.
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ &&
		dz->container == VIPS_FOREIGN_DZ_CONTAINER_FS &&
		dz->dirname &&
		vips_existsf( "%s/%s_files", dz->dirname, dz->basename ) ) {
		vips_error( "dzsave", 
			_( "output directory %s/%s_files exists" ),
			dz->dirname, dz->basename );
		return( -1 ); 
	}

	/* Make the thing we write the tiles into.
	 */
	switch( dz->container ) {
	case VIPS_FOREIGN_DZ_CONTAINER_FS:
		if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ ) {
			/* For deepzoom, we have to rearrange the output
			 * directory after writing it, see the end of this
			 * function. We write to a temporary directory, then
			 * pull ${basename}_files and ${basename}.dzi out into
			 * the current directory and remove the temp. The temp
			 * dir must not clash with another file.
			 */
			char name[VIPS_PATH_MAX];
			int fd;
			GsfOutput *out;
			GError *error = NULL;

			vips_snprintf( name, VIPS_PATH_MAX, "%s-XXXXXX", 
				dz->basename ); 
			dz->tempdir = g_build_filename( dz->dirname, 
				name, NULL );
			if( (fd = g_mkstemp( dz->tempdir )) == -1 ) {
				vips_error(  class->nickname,
					_( "unable to make temporary file %s" ),
					dz->tempdir );
				return( -1 );
			}
			close( fd );
			g_unlink( dz->tempdir );

			if( !(out = (GsfOutput *) 
				gsf_outfile_stdio_new( dz->tempdir, 
					&error )) ) {
				vips_g_error( &error );
				return( -1 );
			}
		
			dz->tree = vips_gsf_tree_new( out, 0 );
		}
		else { 
			GsfOutput *out;
			GError *error = NULL;
			char name[VIPS_PATH_MAX];

			vips_snprintf( name, VIPS_PATH_MAX, "%s/%s", 
				dz->dirname, dz->basename ); 
			if( !(out = (GsfOutput *) 
				gsf_outfile_stdio_new( name, &error )) ) {
				vips_g_error( &error );
				return( -1 );
			}
		
			dz->tree = vips_gsf_tree_new( out, 0 );
		}
		break;

	case VIPS_FOREIGN_DZ_CONTAINER_ZIP:
{
		GsfOutput *zip;
		GsfOutput *out2;
		GError *error = NULL;
		char name[VIPS_PATH_MAX];

		/* Output to a file or memory?
		 */
		if( dz->dirname ) { 
			vips_snprintf( name, VIPS_PATH_MAX, "%s/%s.zip", 
				dz->dirname, dz->basename ); 
			if( !(dz->out = gsf_output_stdio_new( name, &error )) ) {
				vips_g_error( &error );
				return( -1 );
			}
		}
		else
			dz->out = gsf_output_memory_new();

		if( !(zip = (GsfOutput *) 
			gsf_outfile_zip_new( dz->out, &error )) ) {
			vips_g_error( &error );
			return( -1 );
		}

		/* Make the base directory inside the zip. All stuff goes into
		 * this. 
		 */
		out2 = gsf_outfile_new_child_full( (GsfOutfile *) zip, 
			dz->basename, TRUE,
			"compression-level", GSF_ZIP_STORED, 
			NULL );

#ifndef HAVE_GSF_DEFLATE_LEVEL
		if( dz->compression > 0 ) {
			g_warning( "%s", 
				_( "deflate-level not supported by libgsf, "
				"using default compression" ) ); 
			dz->compression = -1;
		}
#endif

		dz->tree = vips_gsf_tree_new( out2, dz->compression );

		/* Note the thing that will need closing up on exit.
		 */
		dz->tree->container = zip; 
}
		break;

	default:
		g_assert_not_reached();
	}

	if( vips_sink_disc( save->ready, pyramid_strip, dz ) )
		return( -1 );

	switch( dz->layout ) {
	case VIPS_FOREIGN_DZ_LAYOUT_DZ:
		if( write_dzi( dz ) )
			return( -1 );
		break;

	case VIPS_FOREIGN_DZ_LAYOUT_ZOOMIFY:
		if( write_properties( dz ) )
			return( -1 );
		break;

	case VIPS_FOREIGN_DZ_LAYOUT_GOOGLE:
		if( write_blank( dz ) )
			return( -1 );
		break;

	default:
		g_assert_not_reached();
	}

	if( dz->properties &&
		write_vips_meta( dz ) )
		return( -1 );

	/* This is so ugly. In earlier versions of dzsave, we wrote x.dzi and
	 * x_files. Now we write x/x.dzi and x/x_files to make it possible to
	 * create zip files. 
	 *
	 * For compatibility, rearrange the directory tree.
	 *
	 * FIXME have a flag to stop this stupidity
	 */
	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_DZ &&
		dz->container == VIPS_FOREIGN_DZ_CONTAINER_FS ) { 
		char old_name[VIPS_PATH_MAX];
		char new_name[VIPS_PATH_MAX];

		vips_snprintf( old_name, VIPS_PATH_MAX, "%s/%s.dzi", 
			dz->tempdir, dz->basename );
		vips_snprintf( new_name, VIPS_PATH_MAX, "%s/%s.dzi", 
			dz->dirname, dz->basename );
		if( vips_rename( old_name, new_name ) )
			return( -1 ); 

		vips_snprintf( old_name, VIPS_PATH_MAX, "%s/%s_files", 
			dz->tempdir, dz->basename );
		vips_snprintf( new_name, VIPS_PATH_MAX, "%s/%s_files", 
			dz->dirname, dz->basename );
		if( vips_rename( old_name, new_name ) )
			return( -1 ); 

		if( vips_rmdirf( "%s", dz->tempdir ) )
			return( -1 ); 
	}

	/* Shut down the output to flush everything.
	 */
	if( vips_gsf_tree_close( dz->tree ) )
		return( -1 ); 
	dz->tree = NULL; 

	/* If we are writing a zip to the filesystem, we must unref out to
	 * force it to disc.
	 */
	if( dz->container == VIPS_FOREIGN_DZ_CONTAINER_ZIP &&
		dz->dirname != NULL ) 
		VIPS_FREEF( g_object_unref, dz->out );

	return( 0 );
}

/* Save a bit of typing.
 */
#define UC VIPS_FORMAT_UCHAR
#define C VIPS_FORMAT_CHAR
#define US VIPS_FORMAT_USHORT
#define S VIPS_FORMAT_SHORT
#define UI VIPS_FORMAT_UINT
#define I VIPS_FORMAT_INT
#define F VIPS_FORMAT_FLOAT
#define X VIPS_FORMAT_COMPLEX
#define D VIPS_FORMAT_DOUBLE
#define DX VIPS_FORMAT_DPCOMPLEX

static int bandfmt_dz[10] = {
/* UC  C   US  S   UI  I   F   X   D   DX */
   UC, C,  US, S,  UI, I,  F,  F,  D,  D
};

static const char *dz_suffs[] = { ".dz", NULL };

static void
vips_foreign_save_dz_class_init( VipsForeignSaveDzClass *class )
{
	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
	VipsObjectClass *object_class = (VipsObjectClass *) class;
	VipsForeignClass *foreign_class = (VipsForeignClass *) class;
	VipsForeignSaveClass *save_class = (VipsForeignSaveClass *) class;

	gobject_class->dispose = vips_foreign_save_dz_dispose;
	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	object_class->nickname = "dzsave_base";
	object_class->description = _( "save image to deep zoom format" );
	object_class->build = vips_foreign_save_dz_build;

	foreign_class->suffs = dz_suffs;

	save_class->saveable = VIPS_SAVEABLE_ANY;
	save_class->format_table = bandfmt_dz;
	save_class->coding[VIPS_CODING_LABQ] = TRUE;

	VIPS_ARG_STRING( class, "basename", 2, 
		_( "Base name" ),
		_( "Base name to save to" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, basename ),
		NULL );

	VIPS_ARG_ENUM( class, "layout", 8, 
		_( "Layout" ), 
		_( "Directory layout" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, layout ),
		VIPS_TYPE_FOREIGN_DZ_LAYOUT, 
			VIPS_FOREIGN_DZ_LAYOUT_DZ ); 

	VIPS_ARG_STRING( class, "suffix", 9, 
		_( "suffix" ), 
		_( "Filename suffix for tiles" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, suffix ),
		".jpeg" );

	VIPS_ARG_INT( class, "overlap", 10, 
		_( "Overlap" ), 
		_( "Tile overlap in pixels" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, overlap ),
		0, 8192, 1 );

	VIPS_ARG_INT( class, "tile_size", 11, 
		_( "Tile size" ), 
		_( "Tile size in pixels" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, tile_size ),
		1, 8192, 254 );

	VIPS_ARG_ENUM( class, "depth", 13, 
		_( "Depth" ), 
		_( "Pyramid depth" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, depth ),
		VIPS_TYPE_FOREIGN_DZ_DEPTH, 
			VIPS_FOREIGN_DZ_DEPTH_ONEPIXEL ); 

	VIPS_ARG_BOOL( class, "centre", 13, 
		_( "Center" ), 
		_( "Center image in tile" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, centre ),
		FALSE );

	VIPS_ARG_ENUM( class, "angle", 14, 
		_( "Angle" ), 
		_( "Rotate image during save" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, angle ),
		VIPS_TYPE_ANGLE, VIPS_ANGLE_D0 ); 

	VIPS_ARG_ENUM( class, "container", 15, 
		_( "Container" ), 
		_( "Pyramid container type" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, container ),
		VIPS_TYPE_FOREIGN_DZ_CONTAINER, 
			VIPS_FOREIGN_DZ_CONTAINER_FS ); 

	VIPS_ARG_BOOL( class, "properties", 16, 
		_( "Properties" ), 
		_( "Write a properties file to the output directory" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, properties ),
		FALSE );

	VIPS_ARG_INT( class, "compression", 17, 
		_( "Compression" ), 
		_( "ZIP deflate compression level" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET( VipsForeignSaveDz, compression ),
		-1, 9, 0 );

	/* How annoying. We stupidly had these in earlier versions.
	 */

	VIPS_ARG_STRING( class, "dirname", 1, 
		_( "Directory name" ),
		_( "Directory name to save to" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT | VIPS_ARGUMENT_DEPRECATED,
		G_STRUCT_OFFSET( VipsForeignSaveDz, dirname ),
		NULL );

	VIPS_ARG_INT( class, "tile_width", 12, 
		_( "Tile width" ), 
		_( "Tile width in pixels" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT | VIPS_ARGUMENT_DEPRECATED,
		G_STRUCT_OFFSET( VipsForeignSaveDz, tile_size ),
		1, 8192, 254 );

	VIPS_ARG_INT( class, "tile_height", 12, 
		_( "Tile height" ), 
		_( "Tile height in pixels" ),
		VIPS_ARGUMENT_OPTIONAL_INPUT | VIPS_ARGUMENT_DEPRECATED,
		G_STRUCT_OFFSET( VipsForeignSaveDz, tile_size ),
		1, 8192, 254 );

}

static void
vips_foreign_save_dz_init( VipsForeignSaveDz *dz )
{
	VIPS_SETSTR( dz->suffix, ".jpeg" );
	dz->layout = VIPS_FOREIGN_DZ_LAYOUT_DZ; 
	dz->overlap = 1;
	dz->tile_size = 254;
	dz->tile_count = 0;
	dz->depth = VIPS_FOREIGN_DZ_DEPTH_ONEPIXEL; 
	dz->angle = VIPS_ANGLE_D0; 
	dz->container = VIPS_FOREIGN_DZ_CONTAINER_FS; 
	dz->compression = 0;
}

typedef struct _VipsForeignSaveDzFile {
	VipsForeignSaveDz parent_object;

	/* Filename for save.
	 */
	char *filename; 

} VipsForeignSaveDzFile;

typedef VipsForeignSaveDzClass VipsForeignSaveDzFileClass;

G_DEFINE_TYPE( VipsForeignSaveDzFile, vips_foreign_save_dz_file, 
	vips_foreign_save_dz_get_type() );

static int
vips_foreign_save_dz_file_build( VipsObject *object )
{
	VipsForeignSaveDz *dz = (VipsForeignSaveDz *) object;
	VipsForeignSaveDzFile *file = (VipsForeignSaveDzFile *) object;

	char *p;

	/* Use @filename to set the default values for dirname and basename.
	 */
	if( !vips_object_argument_isset( object, "basename" ) ) 
		dz->basename = g_path_get_basename( file->filename ); 
	if( !vips_object_argument_isset( object, "dirname" ) ) 
		dz->dirname = g_path_get_dirname( file->filename ); 

	/* Remove any [options] from basename.
	 */
	if( (p = (char *) vips__find_rightmost_brackets( dz->basename )) )
		*p = '\0';

	/* If we're writing thing.zip or thing.szi, default to zip 
	 * container.
	 */
	if( (p = strrchr( dz->basename, '.' )) ) {
		if( !vips_object_argument_isset( object, "container" ) ) 
			if( strcasecmp( p + 1, "zip" ) == 0 ||
				strcasecmp( p + 1, "szi" ) == 0 ) 
				dz->container = VIPS_FOREIGN_DZ_CONTAINER_ZIP;

		/* Remove any legal suffix. We don't remove all suffixes
		 * since we might be writing to a dirname with a dot in.
		 */
		if( strcasecmp( p + 1, "zip" ) == 0 ||
			strcasecmp( p + 1, "szi" ) == 0 || 
			strcasecmp( p + 1, "dz" ) == 0 )
			*p = '\0';
	}

	if( VIPS_OBJECT_CLASS( vips_foreign_save_dz_file_parent_class )->
		build( object ) )
		return( -1 );

	return( 0 );
}

static void
vips_foreign_save_dz_file_class_init( VipsForeignSaveDzFileClass *class )
{
	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
	VipsObjectClass *object_class = (VipsObjectClass *) class;

	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	object_class->nickname = "dzsave";
	object_class->description = _( "save image to deepzoom file" );
	object_class->build = vips_foreign_save_dz_file_build;

	VIPS_ARG_STRING( class, "filename", 1, 
		_( "Filename" ),
		_( "Filename to save to" ),
		VIPS_ARGUMENT_REQUIRED_INPUT, 
		G_STRUCT_OFFSET( VipsForeignSaveDzFile, filename ),
		NULL );
}

static void
vips_foreign_save_dz_file_init( VipsForeignSaveDzFile *file )
{
}

typedef struct _VipsForeignSaveDzBuffer {
	VipsForeignSaveDz parent_object;

	VipsArea *buf;
} VipsForeignSaveDzBuffer;

typedef VipsForeignSaveDzClass VipsForeignSaveDzBufferClass;

G_DEFINE_TYPE( VipsForeignSaveDzBuffer, vips_foreign_save_dz_buffer, 
	vips_foreign_save_dz_get_type() );

static int
vips_foreign_save_dz_buffer_build( VipsObject *object )
{
	VipsForeignSaveDz *dz = (VipsForeignSaveDz *) object;

	void *obuf;
	size_t olen;
	VipsBlob *blob;

	/* Memory output must always be zip.
	 */
	dz->container = VIPS_FOREIGN_DZ_CONTAINER_ZIP;

	if( !vips_object_argument_isset( object, "basename" ) ) 
		dz->basename = g_strdup( "untitled" ); 

	/* Leave dirname NULL to indicate memory output.
	 */

	if( VIPS_OBJECT_CLASS( vips_foreign_save_dz_buffer_parent_class )->
		build( object ) )
		return( -1 );

	g_assert( GSF_IS_OUTPUT_MEMORY( dz->out ) );

	/* Oh dear, we can't steal gsf's memory, and blob can't unref something
	 * or trigger a notify. We have to copy it.
	 *
	 * Don't use tracked, we want something that can be freed with g_free.
	 *
	 * FIXME ... blob (or area?) needs to support notify or unref.
	 */
	olen = gsf_output_size( GSF_OUTPUT( dz->out ) ); 
	if( !(obuf = g_try_malloc( olen )) ) {
		vips_error( "vips_tracked", 
			_( "out of memory --- size == %dMB" ), 
			(int) (olen / (1024.0 * 1024.0))  );
		return( -1 );
	}
	memcpy( obuf, 
		gsf_output_memory_get_bytes( GSF_OUTPUT_MEMORY( dz->out ) ),
		olen ); 

	blob = vips_blob_new( (VipsCallbackFn) g_free, obuf, olen );
	g_object_set( object, "buffer", blob, NULL );
	vips_area_unref( VIPS_AREA( blob ) );

	return( 0 );
}

static void
vips_foreign_save_dz_buffer_class_init( VipsForeignSaveDzBufferClass *class )
{
	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
	VipsObjectClass *object_class = (VipsObjectClass *) class;

	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	object_class->nickname = "dzsave_buffer";
	object_class->description = _( "save image to dz buffer" );
	object_class->build = vips_foreign_save_dz_buffer_build;

	VIPS_ARG_BOXED( class, "buffer", 1, 
		_( "Buffer" ),
		_( "Buffer to save to" ),
		VIPS_ARGUMENT_REQUIRED_OUTPUT, 
		G_STRUCT_OFFSET( VipsForeignSaveDzBuffer, buf ),
		VIPS_TYPE_BLOB );
}

static void
vips_foreign_save_dz_buffer_init( VipsForeignSaveDzBuffer *buffer )
{
}

#endif /*HAVE_GSF*/

/**
 * vips_dzsave:
 * @in: image to save 
 * @name: name to save to 
 * @...: %NULL-terminated list of optional named arguments
 *
 * Optional arguments:
 *
 * * @basename: %gchar, base part of name
 * * @layout: #VipsForeignDzLayout directory layout convention
 * * @suffix: suffix for tile tiles 
 * * @overlap: %gint set tile overlap 
 * * @tile_size: %gint set tile size 
 * * @background: #VipsArrayDouble background colour
 * * @depth: #VipsForeignDzDepth how deep to make the pyramid
 * * @centre: %gboolean centre the tiles 
 * * @angle: #VipsAngle rotate the image by this much
 * * @container: #VipsForeignDzContainer set container type
 * * @properties: %gboolean write a properties file
 * * @compression: %gint zip deflate compression level
 *
 * Save an image as a set of tiles at various resolutions. By default dzsave
 * uses DeepZoom layout -- use @layout to pick other conventions.
 *
 * vips_dzsave() creates a directory called @name to hold the tiles. If @name
 * ends `.zip`, vips_dzsave() will create a zip file called @name to hold the
 * tiles. You can use @container to force zip file output. 
 *
 * Use @basename to set the name of the directory tree we are creating. The
 * default value is set from @name. 
 *
 * You can set @suffix to something like `".jpg[Q=85]"` to control the tile 
 * write options. 
 * 
 * In Google layout mode, edge tiles are expanded to @tile_size by @tile_size 
 * pixels. Normally they are filled with white, but you can set another colour
 * with @background. Images are usually placed at the top-left of the tile,
 * but you can have them centred by turning on @centre. 
 *
 * You can set the size and overlap of tiles with @tile_size and @overlap.
 * They default to the correct settings for the selected @layout. The deepzoom
 * defaults produce 256x256 jpeg files for centre tiles, the most efficient
 * size.
 *
 * Use @depth to control how low the pyramid goes. This defaults to the
 * correct setting for the @layout you select.
 *
 * If @properties is %TRUE, vips_dzsave() will write a file called
 * `vips-properties.xml` to the output directory. This file lists all of the
 * metadata attached to @in in an obvious manner. It can be useful for viewing
 * programs which wish to use fields from source files loaded via
 * vips_openslideload(). 
 *
 * If @container is set to `zip`, you can set a compression level from -1
 * (use zlib default), 0 (store, compression disabled) to 9 (max compression).
 * If no value is given, the default is to store files without compression.
 *
 * See also: vips_tiffsave().
 *
 * Returns: 0 on success, -1 on error.
 */
int
vips_dzsave( VipsImage *in, const char *name, ... )
{
	va_list ap;
	int result;

	va_start( ap, name );
	result = vips_call_split( "dzsave", ap, in, name ); 
	va_end( ap );

	return( result );
}

/**
 * vips_dzsave_buffer:
 * @in: image to save 
 * @buf: return output buffer here
 * @len: return output length here
 * @...: %NULL-terminated list of optional named arguments
 *
 * Optional arguments:
 *
 * * @basename: %gchar, base part of name
 * * @layout: #VipsForeignDzLayout directory layout convention
 * * @suffix: suffix for tile tiles 
 * * @overlap: %gint set tile overlap 
 * * @tile_size: %gint set tile size 
 * * @background: #VipsArrayDouble background colour
 * * @depth: #VipsForeignDzDepth how deep to make the pyramid
 * * @centre: %gboolean centre the tiles 
 * * @angle: #VipsAngle rotate the image by this much
 * * @container: #VipsForeignDzContainer set container type
 * * @properties: %gboolean write a properties file
 * * @compression: %gint zip deflate compression level
 *
 * As vips_dzsave(), but save to a memory buffer. 
 *
 * Output is always in a zip container. Use @basename to set the name of the
 * directory that the zip will create when unzipped. 
 *
 * The address of the buffer is returned in @buf, the length of the buffer in
 * @len. You are responsible for freeing the buffer with g_free() when you
 * are done with it.
 *
 * See also: vips_dzsave(), vips_image_write_to_file().
 *
 * Returns: 0 on success, -1 on error.
 */
int
vips_dzsave_buffer( VipsImage *in, void **buf, size_t *len, ... )
{
	va_list ap;
	VipsArea *area;
	int result;

	area = NULL; 

	va_start( ap, len );
	result = vips_call_split( "dzsave_buffer", ap, in, &area );
	va_end( ap );

	if( !result &&
		area ) { 
		if( buf ) {
			*buf = area->data;
			area->free_fn = NULL;
		}
		if( len ) 
			*len = area->length;

		vips_area_unref( area );
	}

	return( result );
}