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|
#include "fitz.h"
#include "muxps.h"
/*
* TIFF image loader. Should be enough to support TIFF files in XPS.
* Baseline TIFF 6.0 plus CMYK, LZW, Flate and JPEG support.
* Limited bit depths (1,2,4,8).
* Limited planar configurations (1=chunky).
* No tiles (easy fix if necessary).
* TODO: RGBPal images
*/
struct tiff
{
/* "file" */
byte *bp, *rp, *ep;
/* byte order */
unsigned order;
/* where we can find the strips of image data */
unsigned rowsperstrip;
unsigned *stripoffsets;
unsigned *stripbytecounts;
/* colormap */
unsigned *colormap;
/* assorted tags */
unsigned subfiletype;
unsigned photometric;
unsigned compression;
unsigned imagewidth;
unsigned imagelength;
unsigned samplesperpixel;
unsigned bitspersample;
unsigned planar;
unsigned extrasamples;
unsigned xresolution;
unsigned yresolution;
unsigned resolutionunit;
unsigned fillorder;
unsigned g3opts;
unsigned g4opts;
unsigned predictor;
unsigned ycbcrsubsamp[2];
byte *jpegtables; /* point into "file" buffer */
unsigned jpegtableslen;
byte *profile;
int profilesize;
/* decoded data */
fz_colorspace *colorspace;
byte *samples;
int stride;
};
enum
{
TII = 0x4949, /* 'II' */
TMM = 0x4d4d, /* 'MM' */
TBYTE = 1,
TASCII = 2,
TSHORT = 3,
TLONG = 4,
TRATIONAL = 5
};
#define NewSubfileType 254
#define ImageWidth 256
#define ImageLength 257
#define BitsPerSample 258
#define Compression 259
#define PhotometricInterpretation 262
#define FillOrder 266
#define StripOffsets 273
#define SamplesPerPixel 277
#define RowsPerStrip 278
#define StripByteCounts 279
#define XResolution 282
#define YResolution 283
#define PlanarConfiguration 284
#define T4Options 292
#define T6Options 293
#define ResolutionUnit 296
#define Predictor 317
#define ColorMap 320
#define TileWidth 322
#define TileLength 323
#define TileOffsets 324
#define TileByteCounts 325
#define ExtraSamples 338
#define JPEGTables 347
#define YCbCrSubSampling 520
#define ICCProfile 34675
static const byte bitrev[256] =
{
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
};
static int
xps_decode_tiff_uncompressed(struct tiff *tiff, fz_stream *stm, byte *wp, int wlen)
{
int n = fz_read(stm, wp, wlen);
fz_close(stm);
if (n < 0)
return fz_rethrow(n, "cannot read uncompressed strip");
return fz_okay;
}
static int
xps_decode_tiff_packbits(struct tiff *tiff, fz_stream *chain, byte *wp, int wlen)
{
fz_stream *stm = fz_openrld(chain);
int n = fz_read(stm, wp, wlen);
fz_close(stm);
if (n < 0)
return fz_rethrow(n, "cannot read packbits strip");
return fz_okay;
}
static int
xps_decode_tiff_lzw(struct tiff *tiff, fz_stream *chain, byte *wp, int wlen)
{
fz_stream *stm = fz_openlzwd(chain, NULL);
int n = fz_read(stm, wp, wlen);
fz_close(stm);
if (n < 0)
return fz_rethrow(n, "cannot read lzw strip");
return fz_okay;
}
static int
xps_decode_tiff_flate(struct tiff *tiff, fz_stream *chain, byte *wp, int wlen)
{
fz_stream *stm = fz_openflated(chain);
int n = fz_read(stm, wp, wlen);
fz_close(stm);
if (n < 0)
return fz_rethrow(n, "cannot read flate strip");
return fz_okay;
}
static int
xps_decode_tiff_fax(struct tiff *tiff, int comp, fz_stream *chain, byte *wp, int wlen)
{
fz_stream *stm;
fz_obj *params;
fz_obj *columns, *rows, *blackis1, *k, *encodedbytealign;
int n;
columns = fz_newint(tiff->imagewidth);
rows = fz_newint(tiff->imagelength);
blackis1 = fz_newbool(tiff->photometric == 0);
k = fz_newint(comp == 4 ? -1 : 0);
encodedbytealign = fz_newbool(comp == 2);
params = fz_newdict(5);
fz_dictputs(params, "Columns", columns);
fz_dictputs(params, "Rows", rows);
fz_dictputs(params, "BlackIs1", blackis1);
fz_dictputs(params, "K", k);
fz_dictputs(params, "EncodedByteAlign", encodedbytealign);
fz_dropobj(columns);
fz_dropobj(rows);
fz_dropobj(blackis1);
fz_dropobj(k);
fz_dropobj(encodedbytealign);
stm = fz_openfaxd(chain, params);
n = fz_read(stm, wp, wlen);
fz_close(stm);
fz_dropobj(params);
if (n < 0)
return fz_rethrow(n, "cannot read fax strip");
return fz_okay;
}
static int
xps_decode_tiff_jpeg(struct tiff *tiff, fz_stream *chain, byte *wp, int wlen)
{
fz_stream *stm = fz_opendctd(chain, NULL);
int n = fz_read(stm, wp, wlen);
fz_close(stm);
if (n < 0)
return fz_rethrow(n, "cannot read jpeg strip");
return fz_okay;
}
static inline int
getcomp(byte *line, int x, int bpc)
{
switch (bpc)
{
case 1: return (line[x >> 3] >> ( 7 - (x & 7) ) ) & 1;
case 2: return (line[x >> 2] >> ( ( 3 - (x & 3) ) << 1 ) ) & 3;
case 4: return (line[x >> 1] >> ( ( 1 - (x & 1) ) << 2 ) ) & 15;
case 8: return line[x];
case 16: return line[x << 1] << 8 | line[(x << 1) + 1];
}
return 0;
}
static inline void
putcomp(byte *line, int x, int bpc, int value)
{
int maxval = (1 << bpc) - 1;
switch (bpc)
{
case 1: line[x >> 3] &= ~(maxval << (7 - (x & 7))); break;
case 2: line[x >> 2] &= ~(maxval << ((3 - (x & 3)) << 1)); break;
case 4: line[x >> 1] &= ~(maxval << ((1 - (x & 1)) << 2)); break;
}
switch (bpc)
{
case 1: line[x >> 3] |= value << (7 - (x & 7)); break;
case 2: line[x >> 2] |= value << ((3 - (x & 3)) << 1); break;
case 4: line[x >> 1] |= value << ((1 - (x & 1)) << 2); break;
case 8: line[x] = value; break;
case 16: line[x << 1] = value >> 8; line[(x << 1) + 1] = value & 0xFF; break;
}
}
static void
xps_unpredict_tiff(byte *line, int width, int comps, int bits)
{
byte left[32];
int i, k, v;
for (k = 0; k < comps; k++)
left[k] = 0;
for (i = 0; i < width; i++)
{
for (k = 0; k < comps; k++)
{
v = getcomp(line, i * comps + k, bits);
v = v + left[k];
v = v % (1 << bits);
putcomp(line, i * comps + k, bits, v);
left[k] = v;
}
}
}
static void
xps_invert_tiff(byte *line, int width, int comps, int bits, int alpha)
{
int i, k, v;
int m = (1 << bits) - 1;
for (i = 0; i < width; i++)
{
for (k = 0; k < comps; k++)
{
v = getcomp(line, i * comps + k, bits);
if (!alpha || k < comps - 1)
v = m - v;
putcomp(line, i * comps + k, bits, v);
}
}
}
static int
xps_expand_tiff_colormap(struct tiff *tiff)
{
int maxval = 1 << tiff->bitspersample;
byte *samples;
byte *src, *dst;
int stride;
int x, y;
/* colormap has first all red, then all green, then all blue values */
/* colormap values are 0..65535, bits is 4 or 8 */
/* image can be with or without extrasamples: comps is 1 or 2 */
if (tiff->samplesperpixel != 1 && tiff->samplesperpixel != 2)
return fz_throw("invalid number of samples for RGBPal");
if (tiff->bitspersample != 4 && tiff->bitspersample != 8)
return fz_throw("invalid number of bits for RGBPal");
stride = tiff->imagewidth * (tiff->samplesperpixel + 2);
samples = fz_malloc(stride * tiff->imagelength);
for (y = 0; y < tiff->imagelength; y++)
{
src = tiff->samples + (tiff->stride * y);
dst = samples + (stride * y);
for (x = 0; x < tiff->imagewidth; x++)
{
if (tiff->extrasamples)
{
int c = getcomp(src, x * 2, tiff->bitspersample);
int a = getcomp(src, x * 2 + 1, tiff->bitspersample);
*dst++ = tiff->colormap[c + 0] >> 8;
*dst++ = tiff->colormap[c + maxval] >> 8;
*dst++ = tiff->colormap[c + maxval * 2] >> 8;
*dst++ = a << (8 - tiff->bitspersample);
}
else
{
int c = getcomp(src, x, tiff->bitspersample);
*dst++ = tiff->colormap[c + 0] >> 8;
*dst++ = tiff->colormap[c + maxval] >> 8;
*dst++ = tiff->colormap[c + maxval * 2] >> 8;
}
}
}
tiff->samplesperpixel += 2;
tiff->bitspersample = 8;
tiff->stride = stride;
tiff->samples = samples;
return fz_okay;
}
static int
xps_decode_tiff_strips(struct tiff *tiff)
{
fz_stream *stm;
int error;
/* switch on compression to create a filter */
/* feed each strip to the filter */
/* read out the data and pack the samples into an xps_image */
/* type 32773 / packbits -- nothing special (same row-padding as PDF) */
/* type 2 / ccitt rle -- no EOL, no RTC, rows are byte-aligned */
/* type 3 and 4 / g3 and g4 -- each strip starts new section */
/* type 5 / lzw -- each strip is handled separately */
byte *wp;
unsigned row;
unsigned strip;
unsigned i;
if (!tiff->rowsperstrip || !tiff->stripoffsets || !tiff->rowsperstrip)
return fz_throw("no image data in tiff; maybe it is tiled");
if (tiff->planar != 1)
return fz_throw("image data is not in chunky format");
tiff->stride = (tiff->imagewidth * tiff->samplesperpixel * tiff->bitspersample + 7) / 8;
switch (tiff->photometric)
{
case 0: /* WhiteIsZero -- inverted */
tiff->colorspace = fz_devicegray;
break;
case 1: /* BlackIsZero */
tiff->colorspace = fz_devicegray;
break;
case 2: /* RGB */
tiff->colorspace = fz_devicergb;
break;
case 3: /* RGBPal */
tiff->colorspace = fz_devicergb;
break;
case 5: /* CMYK */
tiff->colorspace = fz_devicecmyk;
break;
case 6: /* YCbCr */
/* it's probably a jpeg ... we let jpeg convert to rgb */
tiff->colorspace = fz_devicergb;
break;
default:
return fz_throw("unknown photometric: %d", tiff->photometric);
}
switch (tiff->resolutionunit)
{
case 2:
/* no unit conversion needed */
break;
case 3:
tiff->xresolution = tiff->xresolution * 254 / 100;
tiff->yresolution = tiff->yresolution * 254 / 100;
break;
default:
tiff->xresolution = 96;
tiff->yresolution = 96;
break;
}
/* Note xres and yres could be 0 even if unit was set. If so default to 96dpi. */
if (tiff->xresolution == 0 || tiff->yresolution == 0)
{
tiff->xresolution = 96;
tiff->yresolution = 96;
}
tiff->samples = fz_calloc(tiff->imagelength, tiff->stride);
memset(tiff->samples, 0x55, tiff->imagelength * tiff->stride);
wp = tiff->samples;
strip = 0;
for (row = 0; row < tiff->imagelength; row += tiff->rowsperstrip)
{
unsigned offset = tiff->stripoffsets[strip];
unsigned rlen = tiff->stripbytecounts[strip];
unsigned wlen = tiff->stride * tiff->rowsperstrip;
byte *rp = tiff->bp + offset;
if (wp + wlen > tiff->samples + tiff->stride * tiff->imagelength)
wlen = tiff->samples + tiff->stride * tiff->imagelength - wp;
if (rp + rlen > tiff->ep)
return fz_throw("strip extends beyond the end of the file");
/* the bits are in un-natural order */
if (tiff->fillorder == 2)
for (i = 0; i < rlen; i++)
rp[i] = bitrev[rp[i]];
/* the strip decoders will close this */
stm = fz_openmemory(rp, rlen);
switch (tiff->compression)
{
case 1:
error = xps_decode_tiff_uncompressed(tiff, stm, wp, wlen);
break;
case 2:
error = xps_decode_tiff_fax(tiff, 2, stm, wp, wlen);
break;
case 3:
error = xps_decode_tiff_fax(tiff, 3, stm, wp, wlen);
break;
case 4:
error = xps_decode_tiff_fax(tiff, 4, stm, wp, wlen);
break;
case 5:
error = xps_decode_tiff_lzw(tiff, stm, wp, wlen);
break;
case 6:
error = fz_throw("deprecated JPEG in TIFF compression not supported");
break;
case 7:
error = xps_decode_tiff_jpeg(tiff, stm, wp, wlen);
break;
case 8:
error = xps_decode_tiff_flate(tiff, stm, wp, wlen);
break;
case 32773:
error = xps_decode_tiff_packbits(tiff, stm, wp, wlen);
break;
default:
error = fz_throw("unknown TIFF compression: %d", tiff->compression);
}
if (error)
return fz_rethrow(error, "cannot decode strip %d", row / tiff->rowsperstrip);
/* scramble the bits back into original order */
if (tiff->fillorder == 2)
for (i = 0; i < rlen; i++)
rp[i] = bitrev[rp[i]];
wp += tiff->stride * tiff->rowsperstrip;
strip ++;
}
/* Predictor (only for LZW and Flate) */
if ((tiff->compression == 5 || tiff->compression == 8) && tiff->predictor == 2)
{
byte *p = tiff->samples;
for (i = 0; i < tiff->imagelength; i++)
{
xps_unpredict_tiff(p, tiff->imagewidth, tiff->samplesperpixel, tiff->bitspersample);
p += tiff->stride;
}
}
/* RGBPal */
if (tiff->photometric == 3 && tiff->colormap)
{
error = xps_expand_tiff_colormap(tiff);
if (error)
return fz_rethrow(error, "cannot expand colormap");
}
/* WhiteIsZero .. invert */
if (tiff->photometric == 0)
{
byte *p = tiff->samples;
for (i = 0; i < tiff->imagelength; i++)
{
xps_invert_tiff(p, tiff->imagewidth, tiff->samplesperpixel, tiff->bitspersample, tiff->extrasamples);
p += tiff->stride;
}
}
return fz_okay;
}
static inline int readbyte(struct tiff *tiff)
{
if (tiff->rp < tiff->ep)
return *tiff->rp++;
return EOF;
}
static inline unsigned readshort(struct tiff *tiff)
{
unsigned a = readbyte(tiff);
unsigned b = readbyte(tiff);
if (tiff->order == TII)
return (b << 8) | a;
return (a << 8) | b;
}
static inline unsigned readlong(struct tiff *tiff)
{
unsigned a = readbyte(tiff);
unsigned b = readbyte(tiff);
unsigned c = readbyte(tiff);
unsigned d = readbyte(tiff);
if (tiff->order == TII)
return (d << 24) | (c << 16) | (b << 8) | a;
return (a << 24) | (b << 16) | (c << 8) | d;
}
static void
xps_read_tiff_bytes(unsigned char *p, struct tiff *tiff, unsigned ofs, unsigned n)
{
tiff->rp = tiff->bp + ofs;
if (tiff->rp > tiff->ep)
tiff->rp = tiff->bp;
while (n--)
*p++ = readbyte(tiff);
}
static void
xps_read_tiff_tag_value(unsigned *p, struct tiff *tiff, unsigned type, unsigned ofs, unsigned n)
{
tiff->rp = tiff->bp + ofs;
if (tiff->rp > tiff->ep)
tiff->rp = tiff->bp;
while (n--)
{
switch (type)
{
case TRATIONAL:
*p = readlong(tiff);
*p = *p / readlong(tiff);
p ++;
break;
case TBYTE: *p++ = readbyte(tiff); break;
case TSHORT: *p++ = readshort(tiff); break;
case TLONG: *p++ = readlong(tiff); break;
default: *p++ = 0; break;
}
}
}
static int
xps_read_tiff_tag(struct tiff *tiff, unsigned offset)
{
unsigned tag;
unsigned type;
unsigned count;
unsigned value;
tiff->rp = tiff->bp + offset;
tag = readshort(tiff);
type = readshort(tiff);
count = readlong(tiff);
if ((type == TBYTE && count <= 4) ||
(type == TSHORT && count <= 2) ||
(type == TLONG && count <= 1))
value = tiff->rp - tiff->bp;
else
value = readlong(tiff);
switch (tag)
{
case NewSubfileType:
xps_read_tiff_tag_value(&tiff->subfiletype, tiff, type, value, 1);
break;
case ImageWidth:
xps_read_tiff_tag_value(&tiff->imagewidth, tiff, type, value, 1);
break;
case ImageLength:
xps_read_tiff_tag_value(&tiff->imagelength, tiff, type, value, 1);
break;
case BitsPerSample:
xps_read_tiff_tag_value(&tiff->bitspersample, tiff, type, value, 1);
break;
case Compression:
xps_read_tiff_tag_value(&tiff->compression, tiff, type, value, 1);
break;
case PhotometricInterpretation:
xps_read_tiff_tag_value(&tiff->photometric, tiff, type, value, 1);
break;
case FillOrder:
xps_read_tiff_tag_value(&tiff->fillorder, tiff, type, value, 1);
break;
case SamplesPerPixel:
xps_read_tiff_tag_value(&tiff->samplesperpixel, tiff, type, value, 1);
break;
case RowsPerStrip:
xps_read_tiff_tag_value(&tiff->rowsperstrip, tiff, type, value, 1);
break;
case XResolution:
xps_read_tiff_tag_value(&tiff->xresolution, tiff, type, value, 1);
break;
case YResolution:
xps_read_tiff_tag_value(&tiff->yresolution, tiff, type, value, 1);
break;
case PlanarConfiguration:
xps_read_tiff_tag_value(&tiff->planar, tiff, type, value, 1);
break;
case T4Options:
xps_read_tiff_tag_value(&tiff->g3opts, tiff, type, value, 1);
break;
case T6Options:
xps_read_tiff_tag_value(&tiff->g4opts, tiff, type, value, 1);
break;
case Predictor:
xps_read_tiff_tag_value(&tiff->predictor, tiff, type, value, 1);
break;
case ResolutionUnit:
xps_read_tiff_tag_value(&tiff->resolutionunit, tiff, type, value, 1);
break;
case YCbCrSubSampling:
xps_read_tiff_tag_value(tiff->ycbcrsubsamp, tiff, type, value, 2);
break;
case ExtraSamples:
xps_read_tiff_tag_value(&tiff->extrasamples, tiff, type, value, 1);
break;
case ICCProfile:
tiff->profile = fz_malloc(count);
/* ICC profile data type is set to UNDEFINED.
* TBYTE reading not correct in xps_read_tiff_tag_value */
xps_read_tiff_bytes(tiff->profile, tiff, value, count);
tiff->profilesize = count;
break;
case JPEGTables:
fz_warn("jpeg tables in tiff not implemented");
tiff->jpegtables = tiff->bp + value;
tiff->jpegtableslen = count;
break;
case StripOffsets:
tiff->stripoffsets = fz_calloc(count, sizeof(unsigned));
xps_read_tiff_tag_value(tiff->stripoffsets, tiff, type, value, count);
break;
case StripByteCounts:
tiff->stripbytecounts = fz_calloc(count, sizeof(unsigned));
xps_read_tiff_tag_value(tiff->stripbytecounts, tiff, type, value, count);
break;
case ColorMap:
tiff->colormap = fz_calloc(count, sizeof(unsigned));
xps_read_tiff_tag_value(tiff->colormap, tiff, type, value, count);
break;
case TileWidth:
case TileLength:
case TileOffsets:
case TileByteCounts:
return fz_throw("tiled tiffs not supported");
default:
/* printf("unknown tag: %d t=%d n=%d\n", tag, type, count); */
break;
}
return fz_okay;
}
static void
xps_swap_byte_order(byte *buf, int n)
{
int i, t;
for (i = 0; i < n; i++)
{
t = buf[i * 2 + 0];
buf[i * 2 + 0] = buf[i * 2 + 1];
buf[i * 2 + 1] = t;
}
}
static int
xps_decode_tiff_header(struct tiff *tiff, byte *buf, int len)
{
unsigned version;
unsigned offset;
unsigned count;
unsigned i;
int error;
memset(tiff, 0, sizeof(struct tiff));
tiff->bp = buf;
tiff->rp = buf;
tiff->ep = buf + len;
/* tag defaults, where applicable */
tiff->bitspersample = 1;
tiff->compression = 1;
tiff->samplesperpixel = 1;
tiff->resolutionunit = 2;
tiff->rowsperstrip = 0xFFFFFFFF;
tiff->fillorder = 1;
tiff->planar = 1;
tiff->subfiletype = 0;
tiff->predictor = 1;
tiff->ycbcrsubsamp[0] = 2;
tiff->ycbcrsubsamp[1] = 2;
/*
* Read IFH
*/
/* get byte order marker */
tiff->order = TII;
tiff->order = readshort(tiff);
if (tiff->order != TII && tiff->order != TMM)
return fz_throw("not a TIFF file, wrong magic marker");
/* check version */
version = readshort(tiff);
if (version != 42)
return fz_throw("not a TIFF file, wrong version marker");
/* get offset of IFD */
offset = readlong(tiff);
/*
* Read IFD
*/
tiff->rp = tiff->bp + offset;
count = readshort(tiff);
offset += 2;
for (i = 0; i < count; i++)
{
error = xps_read_tiff_tag(tiff, offset);
if (error)
return fz_rethrow(error, "cannot read TIFF header tag");
offset += 12;
}
return fz_okay;
}
int
xps_decode_tiff(fz_pixmap **imagep, byte *buf, int len)
{
int error;
fz_pixmap *image;
struct tiff tiff;
error = xps_decode_tiff_header(&tiff, buf, len);
if (error)
return fz_rethrow(error, "cannot decode tiff header");
/* Decode the image strips */
if (tiff.rowsperstrip > tiff.imagelength)
tiff.rowsperstrip = tiff.imagelength;
error = xps_decode_tiff_strips(&tiff);
if (error)
return fz_rethrow(error, "cannot decode image data");
/* Byte swap 16-bit images to big endian if necessary */
if (tiff.bitspersample == 16)
{
if (tiff.order == TII)
xps_swap_byte_order(tiff.samples, tiff.imagewidth * tiff.imagelength * tiff.samplesperpixel);
}
/* Expand into fz_pixmap struct */
image = fz_newpixmap(tiff.colorspace, 0, 0, tiff.imagewidth, tiff.imagelength);
image->xres = tiff.xresolution;
image->yres = tiff.yresolution;
fz_unpacktile(image, tiff.samples, tiff.samplesperpixel, tiff.bitspersample, tiff.stride, 0);
/* We should only do this on non-pre-multiplied images, but files in the wild are bad */
if (tiff.extrasamples /* == 2 */)
{
/* CMYK is a subtractive colorspace, we want additive for premul alpha */
if (image->n == 5)
{
fz_pixmap *rgb = fz_newpixmap(fz_devicergb, 0, 0, image->w, image->h);
fz_convertpixmap(image, rgb);
rgb->xres = image->xres;
rgb->yres = image->yres;
fz_droppixmap(image);
image = rgb;
}
fz_premultiplypixmap(image);
}
/* Clean up scratch memory */
if (tiff.colormap) fz_free(tiff.colormap);
if (tiff.stripoffsets) fz_free(tiff.stripoffsets);
if (tiff.stripbytecounts) fz_free(tiff.stripbytecounts);
if (tiff.samples) fz_free(tiff.samples);
*imagep = image;
return fz_okay;
}
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