/* TIFF PARTS:
 * Copyright (c) 1988, 1990 by Sam Leffler.
 * All rights reserved.
 *
 * This file is provided for unrestricted use provided that this
 * legend is included on all tape media and as a part of the
 * software program in whole or part.  Users may copy, modify or
 * distribute this file at will.
 *
 * MODIFICATION FOR VIPS Copyright 1991, K.Martinez 
 *
 * software may be distributed FREE, with these copyright notices
 * no responsibility/warantee is implied or given
 *
 *
 * Modified and added im_LabQ2LabC() function. It can write IM_TYPE_LABQ image
 * in vips format  to LAB in tiff format.
 *  Copyright 1994 Ahmed Abbood.
 *
 * 19/9/95 JC
 *	- calls TIFFClose() more reliably
 *	- tidied up
 * 12/4/97 JC
 *	- thrown away and rewritten for TIFF 6 lib
 * 22/4/97 JC
 *	- writes a pyramid!
 *	- to separate TIFF files tho'
 * 23/4/97 JC
 *	- does 2nd gather pass to put pyramid into a single TIFF file
 *	- ... and shrinks IM_CODING_LABQ too
 * 26/10/98 JC
 *	- binary open for stupid systems
 * 7/6/99 JC
 *	- 16bit TIFF write too
 * 9/7/99 JC
 *	- ZIP tiff added
 * 11/5/00 JC
 *	- removed TIFFmalloc/TIFFfree
 * 5/8/00 JC
 *	- mode string now part of filename
 * 23/4/01 JC
 *	- HAVE_TIFF turns on TIFFness
 * 19/3/02 ruven
 *	- pyramid stops at tile size, not 64x64
 * 29/4/02 JC
 * 	- write any number of bands (but still with photometric RGB, so not
 * 	  very useful)
 * 10/9/02 JC
 *	- oops, handle TIFF errors better
 *	- now writes CMYK correctly
 * 13/2/03 JC
 *	- tries not to write mad resolutions
 * 7/5/03 JC
 *	- only write CMYK if Type == CMYK
 *	- writes EXTRASAMPLES ALPHA for bands == 2 or 4 (if we're writing RGB)
 * 17/11/03 JC
 *	- write float too
 * 28/11/03 JC
 *	- read via a "p" so we work from mmap window images
 *	- uses threadgroups for speedup
 * 9/3/04 JC
 *	- 1 bit write mode added
 * 5/4/04
 *	- better handling of edge tiles (thanks Ruven)
 * 18/5/04 Andrey Kiselev
 *	- added res_inch/res_cm option
 * 20/5/04 JC
 *	- allow single res number too
 * 19/7/04
 *	- write several scanlines at once, good speed up for some cases
 * 22/9/04
 *	- got rid of wrapper image so nip gets progress feedback 
 * 	- fixed tiny read-beyond-buffer issue for edge tiles
 * 7/10/04
 * 	- added ICC profile embedding
 * 13/12/04
 *	- can now pyramid any non-complex type (thanks Ruven)
 * 27/1/05
 *	- added ccittfax4 as a compression option
 * 9/3/05
 *	- set PHOTOMETRIC_CIELAB for vips TYPE_LAB images ... so we can write
 *	  float LAB as well as float RGB
 *	- also LABS images 
 * 22/6/05
 *	- 16 bit LAB write was broken
 * 9/9/05
 * 	- write any icc profile from meta 
 * 3/3/06
 * 	- raise tile buffer limit (thanks Ruven)
 * 11/11/06
 * 	- set ORIENTATION_TOPLEFT (thanks Josef)
 * 18/7/07 Andrey Kiselev
 * 	- remove "b" option on TIFFOpen()
 * 	- support TIFFTAG_PREDICTOR types for lzw and deflate compression
 * 3/11/07
 * 	- use im_wbuffer() for background writes
 * 15/2/08
 * 	- set TIFFTAG_JPEGQUALITY explicitly when we copy TIFF files, since 
 * 	  libtiff doesn't keep this in the header (thanks Joe)
 * 20/2/08
 * 	- use tiff error handler from im_tiff2vips.c
 * 27/2/08
 * 	- don't try to copy icc profiles when building pyramids (thanks Joe)
 * 9/4/08
 * 	- use IM_META_RESOLUTION_UNIT to set default resunit
 * 17/4/08
 * 	- allow CMYKA (thanks Doron)
 * 5/9/08
 *	- trigger eval callbacks during tile write
 * 4/2/10
 * 	- gtkdoc
 * 26/2/10
 * 	- option to turn on bigtiff output
 * 16/4/10
 * 	- use vips_sink_*() instead of threadgroup and friends
 * 22/6/10
 * 	- make no-owner regions for the tile cache, since we share these
 * 	  between threads
 * 12/7/11
 * 	- use im__temp_name() for intermediates rather than polluting the
 * 	  output directory
 * 5/9/11
 * 	- enable YCbCr compression for jpeg write
 * 23/11/11
 * 	- set reduced-resolution subfile type on pyramid layers
 * 2/12/11
 * 	- make into a simple function call ready to be wrapped as a new-style
 * 	  VipsForeign class
 * 7/8/12
 * 	- be more cautious enabling YCbCr mode
 */

/*

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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>

#ifdef HAVE_TIFF

#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /*HAVE_UNISTD_H*/
#include <string.h>

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

#include <tiffio.h>

#include "tiff.h"

/* Max no of tiles we buffer in a layer. Enough to buffer a line of 64x64
 * tiles on a 100k pixel across image.
 */
#define MAX_LAYER_BUFFER (1000)

/* Bits we OR together for quadrants in a tile.
 */
typedef enum pyramid_bits {
	PYR_TL = 1,			/* Top-left etc. */
	PYR_TR = 2,
	PYR_BL = 4,
	PYR_BR = 8,
	PYR_ALL = 15,
	PYR_NONE = 0
} PyramidBits;

/* A tile in our pyramid.
 */
typedef struct pyramid_tile {
	VipsRegion *tile;
	PyramidBits bits;
} PyramidTile;

/* A layer in the pyramid.
 */
typedef struct pyramid_layer {
	/* Parameters.
	 */
	struct tiff_write *tw;		/* Main TIFF write struct */
	int width, height;		/* Layer size */
	int sub;			/* Subsample factor for this layer */

	char *lname;			/* Name of this TIFF file */
	TIFF *tif;			/* TIFF file we write this layer to */
	VipsPel *tbuf;			/* TIFF output buffer */
	PyramidTile tiles[MAX_LAYER_BUFFER];

	struct pyramid_layer *below;	/* Tiles go to here */
	struct pyramid_layer *above;	/* Tiles come from here */
} PyramidLayer;

/* A TIFF image in the process of being written.
 */
typedef struct tiff_write {
	VipsImage *im;			/* Original input image */
	char *name;			/* Final name we write to */

	/* Read from im with these.
	 */
	VipsRegion *reg;

	char *bname;			/* Name for base layer */
	TIFF *tif;			/* Image we write to */

	PyramidLayer *layer;		/* Top of pyramid, if in use */
	VipsPel *tbuf;			/* TIFF output buffer */
	int tls;			/* Tile line size */

	int compression;		/* Compression type */
	int jpqual;			/* JPEG q-factor */
	int predictor;			/* Predictor value */
	int tile;			/* Tile or not */
	int tilew, tileh;		/* Tile size */
	int pyramid;			/* Write pyramid */
	int onebit;			/* Write as 1-bit TIFF */
        int resunit;                    /* Resolution unit (inches or cm) */
        float xres;                    	/* Resolution in X */
        float yres;                    	/* Resolution in Y */
	char *icc_profile;		/* Profile to embed */
	int bigtiff;			/* True for bigtiff write */

	GMutex *write_lock;		/* Lock TIFF*() calls with this */
} TiffWrite;

/* Open TIFF for output.
 */
static TIFF *
tiff_openout( TiffWrite *tw, const char *name )
{
	TIFF *tif;
	const char *mode = tw->bigtiff ? "w8" : "w";

#ifdef DEBUG
	printf( "TIFFOpen( \"%s\", \"%s\" )\n", name, mode );
#endif /*DEBUG*/

	if( !(tif = TIFFOpen( name, mode )) ) {
		vips_error( "vips2tiff", 
			_( "unable to open \"%s\" for output" ), name );
		return( NULL );
	}

	return( tif );
}

/* Open TIFF for input.
 */
static TIFF *
tiff_openin( const char *name )
{
	TIFF *tif;

	if( !(tif = TIFFOpen( name, "r" )) ) {
		vips_error( "vips2tiff", 
			_( "unable to open \"%s\" for input" ), name );
		return( NULL );
	}

	return( tif );
}

/* Convert VIPS LabQ to TIFF LAB. Just take the first three bands.
 */
static void
LabQ2LabC( VipsPel *q, VipsPel *p, int n )
{
        int x;

        for( x = 0; x < n; x++ ) {
                /* Get most significant 8 bits of lab.
                 */
                q[0] = p[0];
                q[1] = p[1];
                q[2] = p[2];

                p += 4;
                q += 3;
        }
}

/* Pack 8 bit VIPS to 1 bit TIFF.
 */
static void
eightbit2onebit( VipsPel *q, VipsPel *p, int n )
{
        int x;
	VipsPel bits;

	bits = 0;
        for( x = 0; x < n; x++ ) {
		bits <<= 1;
		if( p[x] )
			bits |= 1;

		if( (x & 0x7) == 0x7 ) {
			*q++ = bits;
			bits = 0;
		}
        }

	/* Any left-over bits? Need to be left-aligned.
	 */
	if( (x & 0x7) != 0 ) 
		*q++ = bits << (8 - (x & 0x7));
}

/* Convert VIPS LABS to TIFF 16 bit LAB.
 */
static void
LabS2Lab16( VipsPel *q, VipsPel *p, int n )
{
        int x;
	short *p1 = (short *) p;
	unsigned short *q1 = (unsigned short *) q;

        for( x = 0; x < n; x++ ) {
                /* TIFF uses unsigned 16 bit ... move zero, scale up L.
                 */
                q1[0] = (int) p1[0] << 1;
                q1[1] = p1[1];
                q1[2] = p1[2];

                p1 += 3;
                q1 += 3;
        }
}

/* Pack a VIPS region into a TIFF tile buffer.
 */
static void
pack2tiff( TiffWrite *tw, VipsRegion *in, VipsPel *q, VipsRect *area )
{
	int y;

	for( y = area->top; y < VIPS_RECT_BOTTOM( area ); y++ ) {
		VipsPel *p = (VipsPel *) VIPS_REGION_ADDR( in, area->left, y );

		if( in->im->Coding == VIPS_CODING_LABQ )
			LabQ2LabC( q, p, area->width );
		else if( tw->onebit ) 
			eightbit2onebit( q, p, area->width );
		else if( in->im->BandFmt == VIPS_FORMAT_SHORT &&
			in->im->Type == VIPS_INTERPRETATION_LABS )
			LabS2Lab16( q, p, area->width );
		else
			memcpy( q, p, 
				area->width * VIPS_IMAGE_SIZEOF_PEL( in->im ) );

		q += tw->tls;
	}
}

/* Embed an ICC profile from a file.
 */
static int
embed_profile_file( TIFF *tif, const char *profile )
{
	char *buffer;
	unsigned int length;

	if( !(buffer = vips__file_read_name( profile, VIPS_ICC_DIR, &length )) )
		return( -1 );
	TIFFSetField( tif, TIFFTAG_ICCPROFILE, length, buffer );
	vips_free( buffer );

#ifdef DEBUG
	printf( "vips2tiff: attached profile \"%s\"\n", profile );
#endif /*DEBUG*/

	return( 0 );
}

/* Embed an ICC profile from VipsImage metadata.
 */
static int
embed_profile_meta( TIFF *tif, VipsImage *im )
{
	void *data;
	size_t data_length;

	if( vips_image_get_blob( im, VIPS_META_ICC_NAME, &data, &data_length ) )
		return( -1 );
	TIFFSetField( tif, TIFFTAG_ICCPROFILE, data_length, data );

#ifdef DEBUG
	printf( "vips2tiff: attached profile from meta\n" );
#endif /*DEBUG*/

	return( 0 );
}

static int
embed_profile( TiffWrite *tw, TIFF *tif )
{
	if( tw->icc_profile && 
		strcmp( tw->icc_profile, "none" ) != 0 &&
		embed_profile_file( tif, tw->icc_profile ) )
		return( -1 );

	if( !tw->icc_profile && 
		vips_image_get_typeof( tw->im, VIPS_META_ICC_NAME ) &&
		embed_profile_meta( tif, tw->im ) )
		return( -1 );

	return( 0 );
}

/* Write a TIFF header. width and height are the size of the VipsImage we are
 * writing (may have been shrunk!).
 */
static int
write_tiff_header( TiffWrite *tw, TIFF *tif, int width, int height )
{
	uint16 v[1];

	/* Output base header fields.
	 */
	TIFFSetField( tif, TIFFTAG_IMAGEWIDTH, width );
	TIFFSetField( tif, TIFFTAG_IMAGELENGTH, height );
	TIFFSetField( tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG );
	TIFFSetField( tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT );
	TIFFSetField( tif, TIFFTAG_COMPRESSION, tw->compression );

	if( tw->compression == COMPRESSION_JPEG ) 
		TIFFSetField( tif, TIFFTAG_JPEGQUALITY, tw->jpqual );

	if( tw->predictor != -1 ) 
		TIFFSetField( tif, TIFFTAG_PREDICTOR, tw->predictor );

	/* Don't write mad resolutions (eg. zero), it confuses some programs.
	 */
	TIFFSetField( tif, TIFFTAG_RESOLUTIONUNIT, tw->resunit );
	TIFFSetField( tif, TIFFTAG_XRESOLUTION, 
		VIPS_CLIP( 0.01, tw->xres, 10000 ) );
	TIFFSetField( tif, TIFFTAG_YRESOLUTION, 
		VIPS_CLIP( 0.01, tw->yres, 10000 ) );

	/* Attach ICC profile.
	 */
	if( embed_profile( tw, tif ) )
		return( -1 );

	/* And colour fields.
	 */
	if( tw->im->Coding == VIPS_CODING_LABQ ) {
		TIFFSetField( tif, TIFFTAG_SAMPLESPERPIXEL, 3 );
		TIFFSetField( tif, TIFFTAG_BITSPERSAMPLE, 8 );
		TIFFSetField( tif, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_CIELAB );
	}
	else if( tw->onebit ) {
		TIFFSetField( tif, TIFFTAG_SAMPLESPERPIXEL, 1 );
		TIFFSetField( tif, TIFFTAG_BITSPERSAMPLE, 1 );
		TIFFSetField( tif, 
			TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_MINISBLACK );
	}
	else {
		int photometric;

		TIFFSetField( tif, TIFFTAG_SAMPLESPERPIXEL, tw->im->Bands );
		TIFFSetField( tif, TIFFTAG_BITSPERSAMPLE, 
			vips_format_sizeof( tw->im->BandFmt ) << 3 );

		switch( tw->im->Bands ) {
		case 1:
		case 2:
			photometric = PHOTOMETRIC_MINISBLACK;
			if( tw->im->Bands == 2 ) {
				v[0] = EXTRASAMPLE_ASSOCALPHA;
				TIFFSetField( tif, TIFFTAG_EXTRASAMPLES, 1, v );
			}
			break;

		case 3:
		case 4:
			if( tw->im->Type == VIPS_INTERPRETATION_LAB || 
				tw->im->Type == VIPS_INTERPRETATION_LABS ) 
				photometric = PHOTOMETRIC_CIELAB;
			else if( tw->im->Type == VIPS_INTERPRETATION_CMYK ) {
				photometric = PHOTOMETRIC_SEPARATED;
				TIFFSetField( tif, 
					TIFFTAG_INKSET, INKSET_CMYK );
			}
			else if( tw->compression == COMPRESSION_JPEG &&
				tw->im->Bands == 3 &&
				tw->im->BandFmt == VIPS_FORMAT_UCHAR ) { 
				/* This signals to libjpeg that it can do
				 * YCbCr chrominance subsampling from RGB, not
				 * that we will supply the image as YCbCr.
				 */
				photometric = PHOTOMETRIC_YCBCR;
				TIFFSetField( tif, 
					TIFFTAG_JPEGCOLORMODE, 
					JPEGCOLORMODE_RGB );
			}
			else
				photometric = PHOTOMETRIC_RGB;

			if( tw->im->Type != VIPS_INTERPRETATION_CMYK && 
				tw->im->Bands == 4 ) {
				v[0] = EXTRASAMPLE_ASSOCALPHA;
				TIFFSetField( tif, TIFFTAG_EXTRASAMPLES, 1, v );
			}
			break;

		case 5:
			if( tw->im->Type == VIPS_INTERPRETATION_CMYK ) {
				photometric = PHOTOMETRIC_SEPARATED;
				TIFFSetField( tif, 
					TIFFTAG_INKSET, INKSET_CMYK );
			}
			break;

		default:
			g_assert( 0 );
		}

		TIFFSetField( tif, TIFFTAG_PHOTOMETRIC, photometric );
	}

	/* Layout.
	 */
	if( tw->tile ) {
		TIFFSetField( tif, TIFFTAG_TILEWIDTH, tw->tilew );
		TIFFSetField( tif, TIFFTAG_TILELENGTH, tw->tileh );
	}
	else
		TIFFSetField( tif, TIFFTAG_ROWSPERSTRIP, 16 );
	if( tif != tw->tif ) {
		/* Pyramid layer.
		 */
		TIFFSetField( tif, TIFFTAG_SUBFILETYPE, FILETYPE_REDUCEDIMAGE );
	}

	/* Sample format ... for float, we write IEEE.
	 */
	if( tw->im->BandFmt == VIPS_FORMAT_FLOAT )
		TIFFSetField( tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_IEEEFP );

	return( 0 );
}

/* Free a pyramid layer.
 */
static void
free_layer( PyramidLayer *layer )
{
	int i;

	for( i = 0; i < MAX_LAYER_BUFFER; i++ )
		VIPS_FREEF( g_object_unref, layer->tiles[i].tile );

	/* And close the TIFF file we are writing to.
	 */
	VIPS_FREEF( vips_free, layer->tbuf );
	VIPS_FREEF( TIFFClose, layer->tif );
}

/* Free an entire pyramid.
 */
static void
free_pyramid( PyramidLayer *layer )
{
	if( layer->below ) 
		free_pyramid( layer->below );

	free_layer( layer );
}

/* Build a pyramid. w & h are size of layer above this layer. Write new layer
 * struct into *zap, return 0/-1 for success/fail.
 */
static int
build_pyramid( TiffWrite *tw, PyramidLayer *above, 
	PyramidLayer **zap, int w, int h )
{
	PyramidLayer *layer = VIPS_NEW( tw->im, PyramidLayer );
	int i;

	if( !layer )
		return( -1 );
	layer->tw = tw;
	layer->width = w / 2;
	layer->height = h / 2;

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

	layer->lname = NULL;
	layer->tif = NULL;
	layer->tbuf = NULL;

	for( i = 0; i < MAX_LAYER_BUFFER; i++ ) {
		layer->tiles[i].tile = NULL;
		layer->tiles[i].bits = PYR_NONE;
	}

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

	/* Save layer, to make sure it gets freed properly.
	 */
	*zap = layer;

	if( layer->width > tw->tilew || layer->height > tw->tileh ) 
		if( build_pyramid( tw, layer, 
			&layer->below, layer->width, layer->height ) )
			return( -1 );

	if( !(layer->lname = vips__temp_name( "%s.tif" )) )
		return( -1 );

	/* Make output image.
	 */
	if( !(layer->tif = tiff_openout( tw, layer->lname )) ) 
		return( -1 );

	/* Write the TIFF header for this layer.
	 */
	if( write_tiff_header( tw, layer->tif, layer->width, layer->height ) )
		return( -1 );

	if( !(layer->tbuf = vips_malloc( NULL, TIFFTileSize( layer->tif ) )) ) 
		return( -1 );

	return( 0 );
}

/* Pick a new tile to write to in this layer. Either reuse a tile we have
 * previously filled, or make a new one.
 */
static int
find_new_tile( PyramidLayer *layer )
{
	int i;

	/* Exisiting buffer we have finished with? 
	 */
	for( i = 0; i < MAX_LAYER_BUFFER; i++ )
		if( layer->tiles[i].bits == PYR_ALL ) 
			return( i );

	/* Have to make a new one.
	 */
	for( i = 0; i < MAX_LAYER_BUFFER; i++ )
		if( !layer->tiles[i].tile ) {
			if( !(layer->tiles[i].tile = 
				vips_region_new( layer->tw->im )) )
				return( -1 );
			vips__region_no_ownership( layer->tiles[i].tile );
			return( i );
		}

	/* Out of space!
	 */
	vips_error( "vips2tiff", 
		"%s", _( "layer buffer exhausted -- "
			"try making TIFF output tiles smaller" ) );

	return( -1 );
}

/* Find a tile in the layer buffer - if it's not there, make a new one.
 */
static int
find_tile( PyramidLayer *layer, VipsRect *pos )
{
	int i;
	VipsRect quad;
	VipsRect image;
	VipsRect inter;

	/* Do we have a VipsRegion for this position?
	 */
	for( i = 0; i < MAX_LAYER_BUFFER; i++ ) {
		VipsRegion *reg = layer->tiles[i].tile;

		if( reg && reg->valid.left == pos->left && 
			reg->valid.top == pos->top )
			return( i );
	}

	/* Make a new one.
	 */
	if( (i = find_new_tile( layer )) < 0 )
		return( -1 );
	if( vips_region_buffer( layer->tiles[i].tile, pos ) )
		return( -1 );
	layer->tiles[i].bits = PYR_NONE;

	/* Do any quadrants of this tile fall entirely outside the image? 
	 * If they do, set their bits now.
	 */
	quad.width = layer->tw->tilew / 2;
	quad.height = layer->tw->tileh / 2;
	image.left = 0;
	image.top = 0;
	image.width = layer->width;
	image.height = layer->height;

	quad.left = pos->left;
	quad.top = pos->top;
	vips_rect_intersectrect( &quad, &image, &inter );
	if( vips_rect_isempty( &inter ) )
		layer->tiles[i].bits |= PYR_TL;

	quad.left = pos->left + quad.width;
	quad.top = pos->top;
	vips_rect_intersectrect( &quad, &image, &inter );
	if( vips_rect_isempty( &inter ) )
		layer->tiles[i].bits |= PYR_TR;

	quad.left = pos->left;
	quad.top = pos->top + quad.height;
	vips_rect_intersectrect( &quad, &image, &inter );
	if( vips_rect_isempty( &inter ) )
		layer->tiles[i].bits |= PYR_BL;

	quad.left = pos->left + quad.width;
	quad.top = pos->top + quad.height;
	vips_rect_intersectrect( &quad, &image, &inter );
	if( vips_rect_isempty( &inter ) )
		layer->tiles[i].bits |= PYR_BR;

	return( i );
}

/* Shrink a region by a factor of two, writing the result to a specified 
 * offset in another region. VIPS_CODING_LABQ only.
 */
static void
shrink_region_labpack( VipsRegion *from, VipsRect *area, 
	VipsRegion *to, int xoff, int yoff )
{
	int ls = VIPS_REGION_LSKIP( from );
	VipsRect *t = &to->valid;

	int x, y;
	VipsRect out;

	/* Calculate output size and position.
	 */
	out.left = t->left + xoff;
	out.top = t->top + yoff;
	out.width = area->width / 2;
	out.height = area->height / 2;

	/* Shrink ... ignore the extension byte for speed.
	 */
	for( y = 0; y < out.height; y++ ) {
		VipsPel *p = VIPS_REGION_ADDR( from, 
			area->left, area->top + y * 2 );
		VipsPel *q = VIPS_REGION_ADDR( to, out.left, out.top + y );

		for( x = 0; x < out.width; x++ ) {
			signed char *sp = (signed char *) p;
			unsigned char *up = (unsigned char *) p;

			int l = up[0] + up[4] + 
				up[ls] + up[ls + 4];
			int a = sp[1] + sp[5] + 
				sp[ls + 1] + sp[ls + 5];
			int b = sp[2] + sp[6] + 
				sp[ls + 2] + sp[ls + 6];

			q[0] = l >> 2;
			q[1] = a >> 2;
			q[2] = b >> 2;
			q[3] = 0;

			q += 4;
			p += 8;
		}
	}
}

#define SHRINK_TYPE_INT( TYPE ) \
	for( x = 0; x < out.width; x++ ) { \
		TYPE *tp = (TYPE *) p; \
		TYPE *tp1 = (TYPE *) (p + ls); \
		TYPE *tq = (TYPE *) q; \
 		\
		for( z = 0; z < nb; z++ ) { \
			int tot = tp[z] + tp[z + nb] +  \
				tp1[z] + tp1[z + nb]; \
			 \
			tq[z] = tot >> 2; \
		} \
		\
		/* Move on two pels in input. \
		 */ \
		p += ps << 1; \
		q += ps; \
	}

#define SHRINK_TYPE_FLOAT( TYPE ) \
	for( x = 0; x < out.width; x++ ) { \
		TYPE *tp = (TYPE *) p; \
		TYPE *tp1 = (TYPE *) (p + ls); \
		TYPE *tq = (TYPE *) q; \
 		\
		for( z = 0; z < nb; z++ ) { \
			double tot = (double) tp[z] + tp[z + nb] +  \
				tp1[z] + tp1[z + nb]; \
			 \
			tq[z] = tot / 4; \
		} \
		\
		/* Move on two pels in input. \
		 */ \
		p += ps << 1; \
		q += ps; \
	}

/* Shrink a region by a factor of two, writing the result to a specified 
 * offset in another region. n-band, non-complex.
 */
static void
shrink_region( VipsRegion *from, VipsRect *area,
	VipsRegion *to, int xoff, int yoff )
{
	int ls = VIPS_REGION_LSKIP( from );
	int ps = VIPS_IMAGE_SIZEOF_PEL( from->im );
	int nb = from->im->Bands;
	VipsRect *t = &to->valid;

	int x, y, z;
	VipsRect out;

	/* Calculate output size and position.
	 */
	out.left = t->left + xoff;
	out.top = t->top + yoff;
	out.width = area->width / 2;
	out.height = area->height / 2;

	for( y = 0; y < out.height; y++ ) {
		VipsPel *p = VIPS_REGION_ADDR( from, 
			area->left, area->top + y * 2 );
		VipsPel *q = VIPS_REGION_ADDR( to, 
			out.left, out.top + y );

		/* Process this line of pels.
		 */
		switch( from->im->BandFmt ) {
		case VIPS_FORMAT_UCHAR:	
			SHRINK_TYPE_INT( unsigned char );  break; 
		case VIPS_FORMAT_CHAR:	
			SHRINK_TYPE_INT( signed char );  break; 
		case VIPS_FORMAT_USHORT:	
			SHRINK_TYPE_INT( unsigned short );  break; 
		case VIPS_FORMAT_SHORT:	
			SHRINK_TYPE_INT( signed short );  break; 
		case VIPS_FORMAT_UINT:	
			SHRINK_TYPE_INT( unsigned int );  break; 
		case VIPS_FORMAT_INT:	
			SHRINK_TYPE_INT( signed int );  break; 
		case VIPS_FORMAT_FLOAT:	
			SHRINK_TYPE_FLOAT( float );  break; 
		case VIPS_FORMAT_DOUBLE:	
			SHRINK_TYPE_FLOAT( double );  break; 

		default:
			g_assert( 0 );
		}
	}
}

/* Write a tile from a layer.
 */
static int
save_tile( TiffWrite *tw, TIFF *tif, VipsPel *tbuf, VipsRegion *reg, VipsRect *area )
{
	/* Have to repack pixels.
	 */
	pack2tiff( tw, reg, tbuf, area );

#ifdef DEBUG
	printf( "Writing %dx%d pixels at position %dx%d to image %s\n",
		tw->tilew, tw->tileh, area->left, area->top,
		TIFFFileName( tif ) );
#endif /*DEBUG*/

	/* Write to TIFF! easy.
	 */
	if( TIFFWriteTile( tif, tbuf, area->left, area->top, 0, 0 ) < 0 ) {
		vips_error( "vips2tiff", "%s", _( "TIFF write tile failed" ) );
		return( -1 );
	}

	return( 0 );
}

/* A new tile has arrived! Shrink into this layer, if we fill a region, write
 * it and recurse.
 */
static int
new_tile( PyramidLayer *layer, VipsRegion *tile, VipsRect *area )
{
	TiffWrite *tw = layer->tw;
	int xoff, yoff;

	int t, ri, bo;
	VipsRect out, new;
	PyramidBits bit;

	/* Calculate pos and size of new pixels we make inside this layer.
	 */
	new.left = area->left / 2;
	new.top = area->top / 2;
	new.width = area->width / 2;
	new.height = area->height / 2;

	/* Has size fallen to zero? Can happen if this is a one-pixel-wide
	 * strip.
	 */
	if( vips_rect_isempty( &new ) )
		return( 0 );

	/* Offset into this tile ... ie. which quadrant we are writing.
	 */
	xoff = new.left % layer->tw->tilew;
	yoff = new.top % layer->tw->tileh;

	/* Calculate pos for tile we shrink into in this layer.
	 */
	out.left = new.left - xoff;
	out.top = new.top - yoff;

	/* Clip against edge of image.
	 */
	ri = VIPS_MIN( layer->width, out.left + layer->tw->tilew );
	bo = VIPS_MIN( layer->height, out.top + layer->tw->tileh );
	out.width = ri - out.left;
	out.height = bo - out.top;

	if( (t = find_tile( layer, &out )) < 0 )
		return( -1 );

	/* Shrink into place.
	 */
	if( tw->im->Coding == VIPS_CODING_NONE )
		shrink_region( tile, area, 
			layer->tiles[t].tile, xoff, yoff );
	else
		shrink_region_labpack( tile, area, 
			layer->tiles[t].tile, xoff, yoff );

	/* Set that bit.
	 */
	if( xoff )
		if( yoff )
			bit = PYR_BR;
		else
			bit = PYR_TR;
	else
		if( yoff )
			bit = PYR_BL;
		else
			bit = PYR_TL;
	if( layer->tiles[t].bits & bit ) {
		vips_error( "vips2tiff", 
			"%s", _( "internal error #9876345" ) );
		return( -1 );
	}
	layer->tiles[t].bits |= bit;

	if( layer->tiles[t].bits == PYR_ALL ) {
		/* Save this complete tile.
		 */
		if( save_tile( tw, layer->tif, layer->tbuf, 
			layer->tiles[t].tile, &layer->tiles[t].tile->valid ) )
			return( -1 );

		/* And recurse down the pyramid!
		 */
		if( layer->below &&
			new_tile( layer->below, 
				layer->tiles[t].tile, 
				&layer->tiles[t].tile->valid ) )
			return( -1 );
	}

	return( 0 );
}

/* Write as tiles. This is called by vips_sink_tile() for every tile
 * generated.
 */
static int
write_tif_tile( VipsRegion *out, void *seq, void *a, void *b, gboolean *stop )
{
	TiffWrite *tw = (TiffWrite *) a;

	g_mutex_lock( tw->write_lock );

	/* Write to TIFF.
	 */
	if( save_tile( tw, tw->tif, tw->tbuf, out, &out->valid ) ) {
		g_mutex_unlock( tw->write_lock );
		return( -1 );
	}

	/* Is there a pyramid? Write to that too.
	 */
	if( tw->layer && 
		new_tile( tw->layer, out, &out->valid ) ) {
		g_mutex_unlock( tw->write_lock );
		return( -1 );
	}

	g_mutex_unlock( tw->write_lock );

	return( 0 );
}

/* Write as tiles.
 */
static int
write_tif_tilewise( TiffWrite *tw )
{
	VipsImage *im = tw->im;

	g_assert( !tw->tbuf );
	if( !(tw->tbuf = vips_malloc( NULL, TIFFTileSize( tw->tif ) )) ) 
		return( -1 );

	g_assert( !tw->write_lock );
	tw->write_lock = g_mutex_new();

	/* Write pyramid too? Only bother if bigger than tile size.
	 */
	if( tw->pyramid && 
		(im->Xsize > tw->tilew || im->Ysize > tw->tileh) &&
		build_pyramid( tw, NULL, &tw->layer, im->Xsize, im->Ysize ) )
			return( -1 );

	if( vips_sink_tile( im, tw->tilew, tw->tileh,
		NULL, write_tif_tile, NULL, tw, NULL ) ) 
		return( -1 );

	return( 0 );
}

static int
write_tif_block( VipsRegion *region, VipsRect *area, void *a )
{
	TiffWrite *tw = (TiffWrite *) a;
	VipsImage *im = tw->im;

	int y;

	for( y = 0; y < area->height; y++ ) {
		VipsPel *p = VIPS_REGION_ADDR( region, 0, area->top + y );

		/* Any repacking necessary.
		 */
		if( im->Coding == VIPS_CODING_LABQ ) {
			LabQ2LabC( tw->tbuf, p, im->Xsize );
			p = tw->tbuf;
		}
		else if( im->BandFmt == VIPS_FORMAT_SHORT &&
			im->Type == VIPS_INTERPRETATION_LABS ) {
			LabS2Lab16( tw->tbuf, p, im->Xsize );
			p = tw->tbuf;
		}
		else if( tw->onebit ) {
			eightbit2onebit( tw->tbuf, p, im->Xsize );
			p = tw->tbuf;
		}

		if( TIFFWriteScanline( tw->tif, p, area->top + y, 0 ) < 0 ) 
			return( -1 );
	}

	return( 0 );
}

/* Write as scan-lines.
 */
static int
write_tif_stripwise( TiffWrite *tw )
{
	g_assert( !tw->tbuf );

	if( !(tw->tbuf = vips_malloc( NULL, TIFFScanlineSize( tw->tif ) )) ) 
		return( -1 );

	if( vips_sink_disc( tw->im, write_tif_block, tw ) )
		return( -1 );

	return( 0 );
}

/* Delete any temp files we wrote.
 */
static void
delete_files( TiffWrite *tw )
{
	PyramidLayer *layer = tw->layer;

	if( tw->bname ) {
		unlink( tw->bname );
		tw->bname = NULL;
	}

	for( layer = tw->layer; layer; layer = layer->below ) 
		if( layer->lname ) {
			unlink( layer->lname );
			layer->lname = NULL;
		}
}

/* Free a TiffWrite.
 */
static void
free_tiff_write( TiffWrite *tw )
{
#ifndef DEBUG
	delete_files( tw );
#endif /*DEBUG*/

	VIPS_FREEF( TIFFClose, tw->tif );
	VIPS_FREEF( vips_free, tw->tbuf );
	VIPS_FREEF( g_mutex_free, tw->write_lock );
	VIPS_FREEF( free_pyramid, tw->layer );
	VIPS_FREEF( vips_free, tw->icc_profile );
}

/* Round N down to P boundary. 
 */
#define ROUND_DOWN(N,P) ((N) - ((N) % P)) 

/* Round N up to P boundary. 
 */
#define ROUND_UP(N,P) (ROUND_DOWN( (N) + (P) - 1, (P) ))

static int
get_compression( VipsForeignTiffCompression compression )
{
	switch( compression ) {
	case VIPS_FOREIGN_TIFF_COMPRESSION_NONE:
		return( COMPRESSION_NONE );
	case VIPS_FOREIGN_TIFF_COMPRESSION_JPEG:
		return( COMPRESSION_JPEG );
	case VIPS_FOREIGN_TIFF_COMPRESSION_DEFLATE:
		return( COMPRESSION_ADOBE_DEFLATE );
	case VIPS_FOREIGN_TIFF_COMPRESSION_PACKBITS:
		return( COMPRESSION_PACKBITS );
	case VIPS_FOREIGN_TIFF_COMPRESSION_CCITTFAX4:
		return( COMPRESSION_CCITTFAX4 );
	case VIPS_FOREIGN_TIFF_COMPRESSION_LZW:
		return( COMPRESSION_LZW );
	
	default:
		g_assert( 0 );
	}
}

static int
get_resunit( VipsForeignTiffResunit resunit )
{
	switch( resunit ) {
	case VIPS_FOREIGN_TIFF_RESUNIT_CM:
		return( RESUNIT_CENTIMETER );
	case VIPS_FOREIGN_TIFF_RESUNIT_INCH:
		return( RESUNIT_INCH );

	default:
		g_assert( 0 );
	}
}

/* Make and init a TiffWrite.
 */
static TiffWrite *
make_tiff_write( VipsImage *im, const char *filename,
	VipsForeignTiffCompression compression, int Q, 
		VipsForeignTiffPredictor predictor,
	char *profile,
	gboolean tile, int tile_width, int tile_height,
	gboolean pyramid,
	gboolean squash,
	VipsForeignTiffResunit resunit, double xres, double yres,
	gboolean bigtiff )
{
	TiffWrite *tw;

	if( !(tw = VIPS_NEW( im, TiffWrite )) )
		return( NULL );
	tw->im = im;
	tw->name = vips_strdup( VIPS_OBJECT( im ), filename );
	tw->bname = NULL;
	tw->tif = NULL;
	tw->layer = NULL;
	tw->tbuf = NULL;
	tw->compression = get_compression( compression );
	tw->jpqual = Q;
	tw->predictor = predictor;
	tw->tile = tile;
	tw->tilew = tile_width;
	tw->tileh = tile_height;
	tw->pyramid = pyramid;
	tw->onebit = squash;
	tw->icc_profile = profile;
	tw->bigtiff = bigtiff;
	tw->write_lock = NULL;

	tw->resunit = get_resunit( resunit );
	tw->xres = xres;
	tw->yres = yres;

	if( (tw->tilew & 0xf) != 0 || 
		(tw->tileh & 0xf) != 0 ) {
		vips_error( "vips2tiff", 
			"%s", _( "tile size not a multiple of 16" ) );
		return( NULL );
	}

	if( !tw->tile && tw->pyramid ) {
		vips_warn( "vips2tiff", 
			"%s", _( "can't have strip pyramid -- "
			"enabling tiling" ) );
		tw->tile = 1;
	}

	/* We can only pyramid LABQ and non-complex images. 
	 */
	if( tw->pyramid ) {
		if( im->Coding == VIPS_CODING_NONE && 
			vips_bandfmt_iscomplex( im->BandFmt ) ) {
			vips_error( "vips2tiff", 
				"%s", _( "can only pyramid LABQ and "
				"non-complex images" ) );
			return( NULL );
		}
	}

	/* Only 1-bit-ize 8 bit mono images.
	 */
	if( tw->onebit ) {
		if( im->Coding != VIPS_CODING_NONE || 
			im->BandFmt != VIPS_FORMAT_UCHAR ||
			im->Bands != 1 ) 
			tw->onebit = 0;
	}

	if( tw->onebit && tw->compression == COMPRESSION_JPEG ) {
		vips_warn( "vips2tiff", 
			"%s", _( "can't have 1-bit JPEG -- disabling JPEG" ) );
		tw->compression = COMPRESSION_NONE;
	}

	/* Sizeof a line of bytes in the TIFF tile.
	 */
	if( im->Coding == VIPS_CODING_LABQ )
		tw->tls = tw->tilew * 3;
	else if( tw->onebit )
		tw->tls = ROUND_UP( tw->tilew, 8 ) / 8;
	else
		tw->tls = VIPS_IMAGE_SIZEOF_PEL( im ) * tw->tilew;

	return( tw );
}

/* Copy fields.
 */
#define CopyField( tag, v ) \
	if( TIFFGetField( in, tag, &v ) ) TIFFSetField( out, tag, v )

/* Copy a TIFF file ... we know we wrote it, so just copy the tags we know 
 * we might have set.
 */
static int
tiff_copy( TiffWrite *tw, TIFF *out, TIFF *in )
{
	uint32 i32;
	uint16 i16;
	float f;
	tdata_t buf;
	ttile_t tile;
	ttile_t n;

	/* All the fields we might have set.
	 */
	CopyField( TIFFTAG_IMAGEWIDTH, i32 );
	CopyField( TIFFTAG_IMAGELENGTH, i32 );
	CopyField( TIFFTAG_PLANARCONFIG, i16 );
	CopyField( TIFFTAG_ORIENTATION, i16 );
	CopyField( TIFFTAG_XRESOLUTION, f );
	CopyField( TIFFTAG_YRESOLUTION, f );
	CopyField( TIFFTAG_RESOLUTIONUNIT, i16 );
	CopyField( TIFFTAG_COMPRESSION, i16 );
	CopyField( TIFFTAG_SAMPLESPERPIXEL, i16 );
	CopyField( TIFFTAG_BITSPERSAMPLE, i16 );
	CopyField( TIFFTAG_PHOTOMETRIC, i16 );
	CopyField( TIFFTAG_TILEWIDTH, i32 );
	CopyField( TIFFTAG_TILELENGTH, i32 );
	CopyField( TIFFTAG_ROWSPERSTRIP, i32 );
	CopyField( TIFFTAG_SUBFILETYPE, i32 );

	if( tw->predictor != -1 ) 
		TIFFSetField( out, TIFFTAG_PREDICTOR, tw->predictor );

	/* TIFFTAG_JPEGQUALITY is a pesudo-tag, so we can't copy it.
	 * Set explicitly from TiffWrite.
	 */
	if( tw->compression == COMPRESSION_JPEG ) {
		TIFFSetField( out, TIFFTAG_JPEGQUALITY, tw->jpqual );

		/* Only for three-band, 8-bit images.
		 */
		if( tw->im->Bands == 3 &&
			tw->im->BandFmt == VIPS_FORMAT_UCHAR ) { 
			/* Enable rgb->ycbcr conversion in the jpeg write. 
			 */
			TIFFSetField( out, 
				TIFFTAG_JPEGCOLORMODE, JPEGCOLORMODE_RGB );

			/* And we want ycbcr expanded to rgb on read. 
			 * Otherwise TIFFTileSize() will give us the size of 
			 * a chrominance subsampled tile.
			 */
			TIFFSetField( in, 
				TIFFTAG_JPEGCOLORMODE, JPEGCOLORMODE_RGB );
		   }
	}

	/* We can't copy profiles :( Set again from TiffWrite.
	 */
	if( embed_profile( tw, out ) )
		return( -1 );

	buf = vips_malloc( NULL, TIFFTileSize( in ) );
	n = TIFFNumberOfTiles( in );
	for( tile = 0; tile < n; tile++ ) {
		tsize_t len;

		/* It'd be good to use TIFFReadRawTile()/TIFFWriteRawTile() 
		 * here to save compression/decompression, but sadly it seems
		 * not to work :-( investigate at some point.
		 */
		len = TIFFReadEncodedTile( in, tile, buf, (tsize_t) -1 );
		if( len < 0 ||
			TIFFWriteEncodedTile( out, tile, buf, len ) < 0 ) {
			vips_free( buf );
			return( -1 );
		}
	}
	vips_free( buf );

	return( 0 );
}

/* Append a file to a TIFF file.
 */
static int
tiff_append( TiffWrite *tw, TIFF *out, const char *name )
{
	TIFF *in;

	if( !(in = tiff_openin( name )) ) 
		return( -1 );

	if( tiff_copy( tw, out, in ) ) {
		TIFFClose( in );
		return( -1 );
	}
	TIFFClose( in );

	if( !TIFFWriteDirectory( out ) ) 
		return( -1 );

	return( 0 );
}

/* Gather all of the files we wrote into single output file.
 */
static int
gather_pyramid( TiffWrite *tw )
{
	PyramidLayer *layer;
	TIFF *out;

#ifdef DEBUG
	printf( "Starting pyramid gather ...\n" );
#endif /*DEBUG*/

	if( !(out = tiff_openout( tw, tw->name )) ) 
		return( -1 );

	if( tiff_append( tw, out, tw->bname ) ) {
		TIFFClose( out );
		return( -1 );
	}

	for( layer = tw->layer; layer; layer = layer->below ) 
		if( tiff_append( tw, out, layer->lname ) ) {
			TIFFClose( out );
			return( -1 );
		}

	TIFFClose( out );

#ifdef DEBUG
	printf( "Pyramid built\n" );
#endif /*DEBUG*/

	return( 0 );
}


int 
vips__tiff_write( VipsImage *in, const char *filename, 
	VipsForeignTiffCompression compression, int Q, 
		VipsForeignTiffPredictor predictor,
	char *profile,
	gboolean tile, int tile_width, int tile_height,
	gboolean pyramid,
	gboolean squash,
	VipsForeignTiffResunit resunit, double xres, double yres,
	gboolean bigtiff )
{
	TiffWrite *tw;
	int res;

#ifdef DEBUG
	printf( "tiff2vips: libtiff version is \"%s\"\n", TIFFGetVersion() );
#endif /*DEBUG*/

	/* Override the default TIFF error handler.
	 */
	TIFFSetErrorHandler( vips__thandler_error );
	TIFFSetWarningHandler( vips__thandler_warning );

	/* Check input image.
	 */
	if( vips_check_coding_known( "vips2tiff", in ) )
		return( -1 );
	if( in->BandFmt != VIPS_FORMAT_UCHAR && 
		!(in->BandFmt == VIPS_FORMAT_SHORT && 
			in->Type == VIPS_INTERPRETATION_LABS) &&
		in->BandFmt != VIPS_FORMAT_USHORT &&
		in->BandFmt != VIPS_FORMAT_FLOAT ) {
		vips_error( "vips2tiff", "%s", 
			_( "unsigned 8-bit int, 16-bit int, "
			"and 32-bit float only" ) );
		return( -1 );
	}
	if( in->Coding == VIPS_CODING_NONE ) {
		if( in->Bands < 1 || in->Bands > 5 ) {
			vips_error( "vips2tiff", 
				"%s", _( "1 to 5 bands only" ) );
			return( -1 );
		}
	}

	/* Make output image. If this is a pyramid, write the base image to
	 * tmp/xx.tif rather than fred.tif.
	 */
	if( !(tw = make_tiff_write( in, filename,
		compression, Q, predictor, profile,
		tile, tile_width, tile_height, pyramid, squash,
		resunit, xres, yres, bigtiff )) )
		return( -1 );
	if( tw->pyramid ) {
		if( !(tw->bname = vips__temp_name( "%s.tif" )) ||
			!(tw->tif = tiff_openout( tw, tw->bname )) ) {
			free_tiff_write( tw );
			return( -1 );
		}
	}
	else {
		/* No pyramid ... write straight to name.
		 */
		if( !(tw->tif = tiff_openout( tw, tw->name )) ) {
			free_tiff_write( tw );
			return( -1 );
		}
	}

	/* Write the TIFF header for the full-res file.
	 */
	if( write_tiff_header( tw, tw->tif, in->Xsize, in->Ysize ) ) {
		free_tiff_write( tw );
		return( -1 );
	}


	if( tw->tile ) 
		res = write_tif_tilewise( tw );
	else
		res = write_tif_stripwise( tw );
	if( res ) {
		free_tiff_write( tw );
		return( -1 );
	}

	/* Free pyramid resources ... this will TIFFClose() the intermediates,
	 * ready for us to read from them again.
	 */
	if( tw->layer )
		free_pyramid( tw->layer );
	if( tw->tif ) {
		TIFFClose( tw->tif );
		tw->tif = NULL;
	}

	/* Gather layers together into final pyramid file.
	 */
	if( tw->pyramid && gather_pyramid( tw ) ) {
		free_tiff_write( tw );
		return( -1 );
	}

	free_tiff_write( tw );

	return( 0 );
}

#endif /*HAVE_TIFF*/