tiff.c

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/*
 * tiff.c
 *
 * 
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor(s): Jonathan Merritt.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <string.h>

#include "imbuf.h"

#include "BLI_math.h"
#include "BLI_string.h"
#include "BLI_utildefines.h"
 
#include "BKE_global.h"


#include "IMB_imbuf_types.h"
#include "IMB_imbuf.h"

#include "IMB_allocimbuf.h"
#include "IMB_filetype.h"
#include "IMB_filter.h"

#include "tiffio.h"



/***********************
 * Local declarations. *
 ***********************/
/* Reading and writing of an in-memory TIFF file. */
static tsize_t imb_tiff_ReadProc(thandle_t handle, tdata_t data, tsize_t n);
static tsize_t imb_tiff_WriteProc(thandle_t handle, tdata_t data, tsize_t n);
static toff_t  imb_tiff_SeekProc(thandle_t handle, toff_t ofs, int whence);
static int     imb_tiff_CloseProc(thandle_t handle);
static toff_t  imb_tiff_SizeProc(thandle_t handle);
static int     imb_tiff_DummyMapProc(thandle_t fd, tdata_t* pbase, toff_t* psize);
static void    imb_tiff_DummyUnmapProc(thandle_t fd, tdata_t base, toff_t size);


/* Structure for in-memory TIFF file. */
typedef struct ImbTIFFMemFile {
    unsigned char *mem; /* Location of first byte of TIFF file. */
    toff_t offset;      /* Current offset within the file.      */
    tsize_t size;       /* Size of the TIFF file.               */
} ImbTIFFMemFile;
#define IMB_TIFF_GET_MEMFILE(x) ((ImbTIFFMemFile*)(x));



/*****************************
 * Function implementations. *
 *****************************/


static void imb_tiff_DummyUnmapProc(thandle_t fd, tdata_t base, toff_t size)
{
    (void)fd;
    (void)base;
    (void)size;
}

static int imb_tiff_DummyMapProc(thandle_t fd, tdata_t* pbase, toff_t* psize) 
{
    (void)fd;
    (void)pbase;
    (void)psize;

    return (0);
}

static tsize_t imb_tiff_ReadProc(thandle_t handle, tdata_t data, tsize_t n)
{
    tsize_t nRemaining, nCopy;
    ImbTIFFMemFile* mfile;
    void *srcAddr;

    /* get the pointer to the in-memory file */
    mfile = IMB_TIFF_GET_MEMFILE(handle);
    if(!mfile || !mfile->mem) {
        fprintf(stderr, "imb_tiff_ReadProc: !mfile || !mfile->mem!\n");
        return 0;
    }

    /* find the actual number of bytes to read (copy) */
    nCopy = n;
    if((tsize_t)mfile->offset >= mfile->size)
        nRemaining = 0;
    else
        nRemaining = mfile->size - mfile->offset;
    
    if(nCopy > nRemaining)
        nCopy = nRemaining;
    
    /* on EOF, return immediately and read (copy) nothing */
    if(nCopy <= 0)
        return (0);

    /* all set -> do the read (copy) */
    srcAddr = (void*)(&(mfile->mem[mfile->offset]));
    memcpy((void*)data, srcAddr, nCopy);
    mfile->offset += nCopy;     /* advance file ptr by copied bytes */
    return nCopy;
}



static tsize_t imb_tiff_WriteProc(thandle_t handle, tdata_t data, tsize_t n)
{
    (void)handle;
    (void)data;
    (void)n;
    
    printf("imb_tiff_WriteProc: this function should not be called.\n");
    return (-1);
}



static toff_t imb_tiff_SeekProc(thandle_t handle, toff_t ofs, int whence)
{
    ImbTIFFMemFile *mfile;
    toff_t new_offset;

    /* get the pointer to the in-memory file */
    mfile = IMB_TIFF_GET_MEMFILE(handle);
    if(!mfile || !mfile->mem) {
        fprintf(stderr, "imb_tiff_SeekProc: !mfile || !mfile->mem!\n");
        return (-1);
    }

    /* find the location we plan to seek to */
    switch (whence) {
        case SEEK_SET:
            new_offset = ofs;
            break;
        case SEEK_CUR:
            new_offset = mfile->offset + ofs;
            break;
        default:
            /* no other types are supported - return an error */
            fprintf(stderr, 
                "imb_tiff_SeekProc: "
                "Unsupported TIFF SEEK type.\n");
            return (-1);
    }

    /* set the new location */
    mfile->offset = new_offset;
    return mfile->offset;
}



static int imb_tiff_CloseProc(thandle_t handle)
{
    ImbTIFFMemFile *mfile;

    /* get the pointer to the in-memory file */
    mfile = IMB_TIFF_GET_MEMFILE(handle);
    if(!mfile || !mfile->mem) {
        fprintf(stderr,"imb_tiff_CloseProc: !mfile || !mfile->mem!\n");
        return (0);
    }
    
    /* virtually close the file */
    mfile->mem    = NULL;
    mfile->offset = 0;
    mfile->size   = 0;
    
    return (0);
}



static toff_t imb_tiff_SizeProc(thandle_t handle)
{
    ImbTIFFMemFile* mfile;

    /* get the pointer to the in-memory file */
    mfile = IMB_TIFF_GET_MEMFILE(handle);
    if(!mfile || !mfile->mem) {
        fprintf(stderr,"imb_tiff_SizeProc: !mfile || !mfile->mem!\n");
        return (0);
    }

    /* return the size */
    return (toff_t)(mfile->size);
}

static TIFF *imb_tiff_client_open(ImbTIFFMemFile *memFile, unsigned char *mem, size_t size)
{
    /* open the TIFF client layer interface to the in-memory file */
    memFile->mem = mem;
    memFile->offset = 0;
    memFile->size = size;

    return TIFFClientOpen("(Blender TIFF Interface Layer)", 
        "r", (thandle_t)(memFile),
        imb_tiff_ReadProc, imb_tiff_WriteProc,
        imb_tiff_SeekProc, imb_tiff_CloseProc,
        imb_tiff_SizeProc, imb_tiff_DummyMapProc, imb_tiff_DummyUnmapProc);
}

#define IMB_TIFF_NCB 4      /* number of comparison bytes used */
int imb_is_a_tiff(unsigned char *mem)
{
    char big_endian[IMB_TIFF_NCB] = { 0x4d, 0x4d, 0x00, 0x2a };
    char lil_endian[IMB_TIFF_NCB] = { 0x49, 0x49, 0x2a, 0x00 };

    return ( (memcmp(big_endian, mem, IMB_TIFF_NCB) == 0) ||
         (memcmp(lil_endian, mem, IMB_TIFF_NCB) == 0) );
}

static void scanline_contig_16bit(float *rectf, unsigned short *sbuf, int scanline_w, int spp)
{
    int i;
    for (i=0; i < scanline_w; i++) {
        rectf[i*4 + 0] = sbuf[i*spp + 0] / 65535.0;
        rectf[i*4 + 1] = sbuf[i*spp + 1] / 65535.0;
        rectf[i*4 + 2] = sbuf[i*spp + 2] / 65535.0;
        rectf[i*4 + 3] = (spp==4)?(sbuf[i*spp + 3] / 65535.0):1.0;
    }
}

static void scanline_contig_32bit(float *rectf, float *fbuf, int scanline_w, int spp)
{
    int i;
    for (i=0; i < scanline_w; i++) {
        rectf[i*4 + 0] = fbuf[i*spp + 0];
        rectf[i*4 + 1] = fbuf[i*spp + 1];
        rectf[i*4 + 2] = fbuf[i*spp + 2];
        rectf[i*4 + 3] = (spp==4)?fbuf[i*spp + 3]:1.0f;
    }
}

static void scanline_separate_16bit(float *rectf, unsigned short *sbuf, int scanline_w, int chan)
{
    int i;
    for (i=0; i < scanline_w; i++)
        rectf[i*4 + chan] = sbuf[i] / 65535.0;
}

static void scanline_separate_32bit(float *rectf, float *fbuf, int scanline_w, int chan)
{
    int i;
    for (i=0; i < scanline_w; i++)
        rectf[i*4 + chan] = fbuf[i];
}

static void imb_read_tiff_resolution(ImBuf *ibuf, TIFF *image)
{
    uint16 unit;
    float xres;
    float yres;

    TIFFGetFieldDefaulted(image, TIFFTAG_RESOLUTIONUNIT, &unit);
    TIFFGetFieldDefaulted(image, TIFFTAG_XRESOLUTION, &xres);
    TIFFGetFieldDefaulted(image, TIFFTAG_YRESOLUTION, &yres);

    if(unit == RESUNIT_CENTIMETER) {
        ibuf->ppm[0]= (double)xres * 100.0;
        ibuf->ppm[1]= (double)yres * 100.0;
    }
    else {
        ibuf->ppm[0]= (double)xres / 0.0254;
        ibuf->ppm[1]= (double)yres / 0.0254;
    }
}

/* 
 * Use the libTIFF scanline API to read a TIFF image.
 * This method is most flexible and can handle multiple different bit depths 
 * and RGB channel orderings.
 */
static int imb_read_tiff_pixels(ImBuf *ibuf, TIFF *image, int premul)
{
    ImBuf *tmpibuf;
    int success= 0;
    short bitspersample, spp, config;
    size_t scanline;
    int ib_flag=0, row, chan;
    float *fbuf=NULL;
    unsigned short *sbuf=NULL;

    TIFFGetField(image, TIFFTAG_BITSPERSAMPLE, &bitspersample);
    TIFFGetField(image, TIFFTAG_SAMPLESPERPIXEL, &spp);     /* number of 'channels' */
    TIFFGetField(image, TIFFTAG_PLANARCONFIG, &config);

    imb_read_tiff_resolution(ibuf, image);

    scanline = TIFFScanlineSize(image);
    
    if (bitspersample == 32) {
        ib_flag = IB_rectfloat;
        fbuf = (float *)_TIFFmalloc(scanline);
    } else if (bitspersample == 16) {
        ib_flag = IB_rectfloat;
        sbuf = (unsigned short *)_TIFFmalloc(scanline);
    } else {
        ib_flag = IB_rect;
    }
    
    tmpibuf= IMB_allocImBuf(ibuf->x, ibuf->y, ibuf->planes, ib_flag);
    
    /* simple RGBA image */
    if (!(bitspersample == 32 || bitspersample == 16)) {
        success |= TIFFReadRGBAImage(image, ibuf->x, ibuf->y, tmpibuf->rect, 0);
    }
    /* contiguous channels: RGBRGBRGB */
    else if (config == PLANARCONFIG_CONTIG) {
        for (row = 0; row < ibuf->y; row++) {
            int ib_offset = ibuf->x*ibuf->y*4 - ibuf->x*4 * (row+1);
        
            if (bitspersample == 32) {
                success |= TIFFReadScanline(image, fbuf, row, 0);
                scanline_contig_32bit(tmpibuf->rect_float+ib_offset, fbuf, ibuf->x, spp);
                
            } else if (bitspersample == 16) {
                success |= TIFFReadScanline(image, sbuf, row, 0);
                scanline_contig_16bit(tmpibuf->rect_float+ib_offset, sbuf, ibuf->x, spp);
            }
        }
    /* separate channels: RRRGGGBBB */
    } else if (config == PLANARCONFIG_SEPARATE) {
        
        /* imbufs always have 4 channels of data, so we iterate over all of them
         * but only fill in from the TIFF scanline where necessary. */
        for (chan = 0; chan < 4; chan++) {
            for (row = 0; row < ibuf->y; row++) {
                int ib_offset = ibuf->x*ibuf->y*4 - ibuf->x*4 * (row+1);
                
                if (bitspersample == 32) {
                    if (chan == 3 && spp == 3) /* fill alpha if only RGB TIFF */
                        memset(fbuf, 1.0, sizeof(fbuf));
                    else
                        success |= TIFFReadScanline(image, fbuf, row, chan);
                    scanline_separate_32bit(tmpibuf->rect_float+ib_offset, fbuf, ibuf->x, chan);
                    
                } else if (bitspersample == 16) {
                    if (chan == 3 && spp == 3) /* fill alpha if only RGB TIFF */
                        memset(sbuf, 65535, sizeof(sbuf));
                    else
                        success |= TIFFReadScanline(image, sbuf, row, chan);
                    scanline_separate_16bit(tmpibuf->rect_float+ib_offset, sbuf, ibuf->x, chan);
                    
                }
            }
        }
    }
    
    if (bitspersample == 32)
        _TIFFfree(fbuf);
    else if (bitspersample == 16)
        _TIFFfree(sbuf);

    if(success) {
        ibuf->profile = (bitspersample==32)?IB_PROFILE_LINEAR_RGB:IB_PROFILE_SRGB;

//      Code seems to be not needed for 16 bits tif, on PPC G5 OSX (ton)
        if(bitspersample < 16)
            if(ENDIAN_ORDER == B_ENDIAN)
                IMB_convert_rgba_to_abgr(tmpibuf);
        if(premul) {
            IMB_premultiply_alpha(tmpibuf);
            ibuf->flags |= IB_premul;
        }
        
        /* assign rect last */
        if (tmpibuf->rect_float)
            ibuf->rect_float= tmpibuf->rect_float;
        else    
            ibuf->rect= tmpibuf->rect;
        ibuf->mall |= ib_flag;
        ibuf->flags |= ib_flag;
        
        tmpibuf->mall &= ~ib_flag;
    }

    IMB_freeImBuf(tmpibuf);
    
    return success;
}

void imb_inittiff(void)
{
    if (!(G.f & G_DEBUG))
        TIFFSetErrorHandler(NULL);
}

ImBuf *imb_loadtiff(unsigned char *mem, size_t size, int flags)
{
    TIFF *image = NULL;
    ImBuf *ibuf = NULL, *hbuf;
    ImbTIFFMemFile memFile;
    uint32 width, height;
    char *format = NULL;
    int level;
    short spp;
    int ib_depth;

    /* check whether or not we have a TIFF file */
    if(size < IMB_TIFF_NCB) {
        fprintf(stderr, "imb_loadtiff: size < IMB_TIFF_NCB\n");
        return NULL;
    }
    if(imb_is_a_tiff(mem) == 0)
        return NULL;

    image = imb_tiff_client_open(&memFile, mem, size);

    if(image == NULL) {
        printf("imb_loadtiff: could not open TIFF IO layer.\n");
        return NULL;
    }

    /* allocate the image buffer */
    TIFFGetField(image, TIFFTAG_IMAGEWIDTH,  &width);
    TIFFGetField(image, TIFFTAG_IMAGELENGTH, &height);
    TIFFGetField(image, TIFFTAG_SAMPLESPERPIXEL, &spp);
    
    ib_depth = (spp==3)?24:32;
    
    ibuf = IMB_allocImBuf(width, height, ib_depth, 0);
    if(ibuf) {
        ibuf->ftype = TIF;
    }
    else {
        fprintf(stderr, 
            "imb_loadtiff: could not allocate memory for TIFF "
            "image.\n");
        TIFFClose(image);
        return NULL;
    }

    /* if testing, we're done */
    if(flags & IB_test) {
        TIFFClose(image);
        return ibuf;
    }

    /* detect if we are reading a tiled/mipmapped texture, in that case
       we don't read pixels but leave it to the cache to load tiles */
    if(flags & IB_tilecache) {
        format= NULL;
        TIFFGetField(image, TIFFTAG_PIXAR_TEXTUREFORMAT, &format);

        if(format && strcmp(format, "Plain Texture")==0 && TIFFIsTiled(image)) {
            int numlevel = TIFFNumberOfDirectories(image);

            /* create empty mipmap levels in advance */
            for(level=0; level<numlevel; level++) {
                if(!TIFFSetDirectory(image, level))
                    break;

                if(level > 0) {
                    width= (width > 1)? width/2: 1;
                    height= (height > 1)? height/2: 1;

                    hbuf= IMB_allocImBuf(width, height, 32, 0);
                    hbuf->miplevel= level;
                    hbuf->ftype= ibuf->ftype;
                    ibuf->mipmap[level-1] = hbuf;

                    if(flags & IB_premul)
                        hbuf->flags |= IB_premul;
                }
                else
                    hbuf= ibuf;

                hbuf->flags |= IB_tilecache;

                TIFFGetField(image, TIFFTAG_TILEWIDTH, &hbuf->tilex);
                TIFFGetField(image, TIFFTAG_TILELENGTH, &hbuf->tiley);

                hbuf->xtiles= ceil(hbuf->x/(float)hbuf->tilex);
                hbuf->ytiles= ceil(hbuf->y/(float)hbuf->tiley);

                imb_addtilesImBuf(hbuf);

                ibuf->miptot++;
            }
        }
    }

    /* read pixels */
    if(!(ibuf->flags & IB_tilecache) && !imb_read_tiff_pixels(ibuf, image, 0)) {
        fprintf(stderr, "imb_loadtiff: Failed to read tiff image.\n");
        TIFFClose(image);
        return NULL;
    }

    /* close the client layer interface to the in-memory file */
    TIFFClose(image);

    /* return successfully */
    return ibuf;
}

void imb_loadtiletiff(ImBuf *ibuf, unsigned char *mem, size_t size, int tx, int ty, unsigned int *rect)
{
    TIFF *image = NULL;
    uint32 width, height;
    ImbTIFFMemFile memFile;

    image = imb_tiff_client_open(&memFile, mem, size);

    if(image == NULL) {
        printf("imb_loadtiff: could not open TIFF IO layer for loading mipmap level.\n");
        return;
    }

    if(TIFFSetDirectory(image, ibuf->miplevel)) { /* allocate the image buffer */
        TIFFGetField(image, TIFFTAG_IMAGEWIDTH,  &width);
        TIFFGetField(image, TIFFTAG_IMAGELENGTH, &height);

        if(width == ibuf->x && height == ibuf->y) {
            if(rect) {
                /* tiff pixels are bottom to top, tiles are top to bottom */
                if(TIFFReadRGBATile(image, tx*ibuf->tilex, (ibuf->ytiles - 1 - ty)*ibuf->tiley, rect) == 1) {
                    if(ibuf->tiley > ibuf->y)
                        memmove(rect, rect+ibuf->tilex*(ibuf->tiley - ibuf->y), sizeof(int)*ibuf->tilex*ibuf->y);

                    if(ibuf->flags & IB_premul)
                        IMB_premultiply_rect(rect, 32, ibuf->tilex, ibuf->tiley);
                }
                else
                    printf("imb_loadtiff: failed to read tiff tile at mipmap level %d\n", ibuf->miplevel);
            }
        }
        else
            printf("imb_loadtiff: mipmap level %d has unexpected size %ux%u instead of %dx%d\n", ibuf->miplevel, width, height, ibuf->x, ibuf->y);
    }
    else
        printf("imb_loadtiff: could not find mipmap level %d\n", ibuf->miplevel);

    /* close the client layer interface to the in-memory file */
    TIFFClose(image);
}

int imb_savetiff(ImBuf *ibuf, const char *name, int flags)
{
    TIFF *image = NULL;
    uint16 samplesperpixel, bitspersample;
    size_t npixels;
    unsigned char *pixels = NULL;
    unsigned char *from = NULL, *to = NULL;
    unsigned short *pixels16 = NULL, *to16 = NULL;
    float *fromf = NULL;
    float xres, yres;
    int x, y, from_i, to_i, i;
    int extraSampleTypes[1] = { EXTRASAMPLE_ASSOCALPHA };
    

    /* check for a valid number of bytes per pixel.  Like the PNG writer,
     * the TIFF writer supports 1, 3 or 4 bytes per pixel, corresponding
     * to gray, RGB, RGBA respectively. */
    samplesperpixel = (uint16)((ibuf->planes + 7) >> 3);
    if((samplesperpixel > 4) || (samplesperpixel == 2)) {
        fprintf(stderr,
            "imb_savetiff: unsupported number of bytes per " 
            "pixel: %d\n", samplesperpixel);
        return (0);
    }

    if((ibuf->ftype & TIF_16BIT) && ibuf->rect_float)
        bitspersample = 16;
    else
        bitspersample = 8;

    /* open TIFF file for writing */
    if(flags & IB_mem) {
        /* bork at the creation of a TIFF in memory */
        fprintf(stderr,
            "imb_savetiff: creation of in-memory TIFF files is " 
            "not yet supported.\n");
        return (0);
    }
    else {
        /* create image as a file */
        image = TIFFOpen(name, "w");
    }
    if(image == NULL) {
        fprintf(stderr,
            "imb_savetiff: could not open TIFF for writing.\n");
        return (0);
    }

    /* allocate array for pixel data */
    npixels = ibuf->x * ibuf->y;
    if(bitspersample == 16)
        pixels16 = (unsigned short*)_TIFFmalloc(npixels *
            samplesperpixel * sizeof(unsigned short));
    else
        pixels = (unsigned char*)_TIFFmalloc(npixels *
            samplesperpixel * sizeof(unsigned char));

    if(pixels == NULL && pixels16 == NULL) {
        fprintf(stderr,
            "imb_savetiff: could not allocate pixels array.\n");
        TIFFClose(image);
        return (0);
    }

    /* setup pointers */
    if(bitspersample == 16) {
        fromf = ibuf->rect_float;
        to16   = pixels16;
    }
    else {
        from = (unsigned char*)ibuf->rect;
        to   = pixels;
    }

    /* setup samples per pixel */
    TIFFSetField(image, TIFFTAG_BITSPERSAMPLE, bitspersample);
    TIFFSetField(image, TIFFTAG_SAMPLESPERPIXEL, samplesperpixel);

    if(samplesperpixel == 4) {
        /* RGBA images */
        TIFFSetField(image, TIFFTAG_EXTRASAMPLES, 1,
                extraSampleTypes);
        TIFFSetField(image, TIFFTAG_PHOTOMETRIC, 
                PHOTOMETRIC_RGB);
    }
    else if(samplesperpixel == 3) {
        /* RGB images */
        TIFFSetField(image, TIFFTAG_PHOTOMETRIC,
                PHOTOMETRIC_RGB);
    }
    else if(samplesperpixel == 1) {
        /* greyscale images, 1 channel */
        TIFFSetField(image, TIFFTAG_PHOTOMETRIC,
                PHOTOMETRIC_MINISBLACK);
    }

    /* copy pixel data.  While copying, we flip the image vertically. */
    for(x = 0; x < ibuf->x; x++) {
        for(y = 0; y < ibuf->y; y++) {
            from_i = 4*(y*ibuf->x+x);
            to_i   = samplesperpixel*((ibuf->y-y-1)*ibuf->x+x);

            if(pixels16) {
                /* convert from float source */
                float rgb[3];
                
                if (ibuf->profile == IB_PROFILE_LINEAR_RGB)
                    linearrgb_to_srgb_v3_v3(rgb, &fromf[from_i]);
                else
                    copy_v3_v3(rgb, &fromf[from_i]);

                to16[to_i+0] = FTOUSHORT(rgb[0]);
                to16[to_i+1] = FTOUSHORT(rgb[1]);
                to16[to_i+2] = FTOUSHORT(rgb[2]);
                to_i += 3; from_i+=3;
                
                if (samplesperpixel == 4) {
                    to16[to_i+3] = FTOUSHORT(fromf[from_i+3]);
                    /*to_i++; from_i++;*/ /*unused, set on each loop */
                }
            }
            else {
                for(i = 0; i < samplesperpixel; i++, to_i++, from_i++)
                    to[to_i] = from[from_i];
            }
        }
    }

    /* write the actual TIFF file */
    TIFFSetField(image, TIFFTAG_IMAGEWIDTH,      ibuf->x);
    TIFFSetField(image, TIFFTAG_IMAGELENGTH,     ibuf->y);
    TIFFSetField(image, TIFFTAG_ROWSPERSTRIP,    ibuf->y);
    TIFFSetField(image, TIFFTAG_COMPRESSION, COMPRESSION_DEFLATE);
    TIFFSetField(image, TIFFTAG_FILLORDER, FILLORDER_MSB2LSB);
    TIFFSetField(image, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);


    if(ibuf->ppm[0] > 0.0 && ibuf->ppm[1] > 0.0) {
        xres= (float)(ibuf->ppm[0] * 0.0254);
        yres= (float)(ibuf->ppm[1] * 0.0254);
    }
    else {
        xres= yres= 150.0f;
    }

    TIFFSetField(image, TIFFTAG_XRESOLUTION,     xres);
    TIFFSetField(image, TIFFTAG_YRESOLUTION,     yres);
    TIFFSetField(image, TIFFTAG_RESOLUTIONUNIT,  RESUNIT_INCH);
    if(TIFFWriteEncodedStrip(image, 0,
            (bitspersample == 16)? (unsigned char*)pixels16: pixels,
            ibuf->x*ibuf->y*samplesperpixel*bitspersample/8) == -1) {
        fprintf(stderr,
            "imb_savetiff: Could not write encoded TIFF.\n");
        TIFFClose(image);
        if(pixels) _TIFFfree(pixels);
        if(pixels16) _TIFFfree(pixels16);
        return (1);
    }

    /* close the TIFF file */
    TIFFClose(image);
    if(pixels) _TIFFfree(pixels);
    if(pixels16) _TIFFfree(pixels16);
    return (1);
}