tif_luv.c

一个国人自己实现图像库的程序（有参考价值）

/*
 * Copyright (c) 1997 Greg Ward Larson
 * Copyright (c) 1997 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler, Greg Larson and Silicon Graphics may not be used in any
 * advertising or publicity relating to the software without the specific,
 * prior written permission of Sam Leffler, Greg Larson and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 * 
 * IN NO EVENT SHALL SAM LEFFLER, GREG LARSON OR SILICON GRAPHICS BE LIABLE
 * FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

#include "tiffiop.h"
#ifdef LOGLUV_SUPPORT

/*
 * TIFF Library.
 * LogLuv compression support for high dynamic range images.
 *
 * Contributed by Greg Larson.
 *
 * LogLuv image support uses the TIFF library to store 16 or 10-bit
 * log luminance values with 8 bits each of u and v or a 14-bit index.
 *
 * The codec can take as input and produce as output 32-bit IEEE float values 
 * as well as 16-bit integer values.  A 16-bit luminance is interpreted
 * as a sign bit followed by a 15-bit integer that is converted
 * to and from a linear magnitude using the transformation:
 *
 *	L = 2^( (Le+.5)/256 - 64 )		# real from 15-bit
 *
 *	Le = floor( 256*(log2(L) + 64) )	# 15-bit from real
 *
 * The actual conversion to world luminance units in candelas per sq. meter
 * requires an additional multiplier, which is stored in the TIFFTAG_STONITS.
 * This value is usually set such that a reasonable exposure comes from
 * clamping decoded luminances above 1 to 1 in the displayed image.
 *
 * The 16-bit values for u and v may be converted to real values by dividing
 * each by 32768.  (This allows for negative values, which aren't useful as
 * far as we know, but are left in case of future improvements in human
 * color vision.)
 *
 * Conversion from (u,v), which is actually the CIE (u',v') system for
 * you color scientists, is accomplished by the following transformation:
 *
 *	u = 4*x / (-2*x + 12*y + 3)
 *	v = 9*y / (-2*x + 12*y + 3)
 *
 *	x = 9*u / (6*u - 16*v + 12)
 *	y = 4*v / (6*u - 16*v + 12)
 *
 * This process is greatly simplified by passing 32-bit IEEE floats
 * for each of three CIE XYZ coordinates.  The codec then takes care
 * of conversion to and from LogLuv, though the application is still
 * responsible for interpreting the TIFFTAG_STONITS calibration factor.
 *
 * By definition, a CIE XYZ vector of [1 1 1] corresponds to a neutral white
 * point of (x,y)=(1/3,1/3).  However, most color systems assume some other
 * white point, such as D65, and an absolute color conversion to XYZ then
 * to another color space with a different white point may introduce an
 * unwanted color cast to the image.  It is often desirable, therefore, to
 * perform a white point conversion that maps the input white to [1 1 1]
 * in XYZ, then record the original white point using the TIFFTAG_WHITEPOINT
 * tag value.  A decoder that demands absolute color calibration may use
 * this white point tag to get back the original colors, but usually it
 * will be ignored and the new white point will be used instead that
 * matches the output color space.
 *
 * Pixel information is compressed into one of two basic encodings, depending
 * on the setting of the compression tag, which is one of COMPRESSION_SGILOG
 * or COMPRESSION_SGILOG24.  For COMPRESSION_SGILOG, greyscale data is
 * stored as:
 *
 *	 1       15
 *	|-+---------------|
 *
 * COMPRESSION_SGILOG color data is stored as:
 *
 *	 1       15           8        8
 *	|-+---------------|--------+--------|
 *	 S       Le           ue       ve
 *
 * For the 24-bit COMPRESSION_SGILOG24 color format, the data is stored as:
 *
 *	     10           14
 *	|----------|--------------|
 *	     Le'          Ce
 *
 * There is no sign bit in the 24-bit case, and the (u,v) chromaticity is
 * encoded as an index for optimal color resolution.  The 10 log bits are
 * defined by the following conversions:
 *
 *	L = 2^((Le'+.5)/64 - 12)		# real from 10-bit
 *
 *	Le' = floor( 64*(log2(L) + 12) )	# 10-bit from real
 *
 * The 10 bits of the smaller format may be converted into the 15 bits of
 * the larger format by multiplying by 4 and adding 13314.  Obviously,
 * a smaller range of magnitudes is covered (about 5 orders of magnitude
 * instead of 38), and the lack of a sign bit means that negative luminances
 * are not allowed.  (Well, they aren't allowed in the real world, either,
 * but they are useful for certain types of image processing.)
 *
 * The desired user format is controlled by the setting the internal
 * pseudo tag TIFFTAG_SGILOGDATAFMT to one of:
 *  SGILOGDATAFMT_FLOAT       = IEEE 32-bit float XYZ values
 *  SGILOGDATAFMT_16BIT	      = 16-bit integer encodings of logL, u and v
 * Raw data i/o is also possible using:
 *  SGILOGDATAFMT_RAW         = 32-bit unsigned integer with encoded pixel
 * In addition, the following decoding is provided for ease of display:
 *  SGILOGDATAFMT_8BIT        = 8-bit default RGB gamma-corrected values
 *
 * For grayscale images, we provide the following data formats:
 *  SGILOGDATAFMT_FLOAT       = IEEE 32-bit float Y values
 *  SGILOGDATAFMT_16BIT       = 16-bit integer w/ encoded luminance
 *  SGILOGDATAFMT_8BIT        = 8-bit gray monitor values
 *
 * Note that the COMPRESSION_SGILOG applies a simple run-length encoding
 * scheme by separating the logL, u and v bytes for each row and applying
 * a PackBits type of compression.  Since the 24-bit encoding is not
 * adaptive, the 32-bit color format takes less space in many cases.
 *
 * Further control is provided over the conversion from higher-resolution
 * formats to final encoded values through the pseudo tag
 * TIFFTAG_SGILOGENCODE:
 *  SGILOGENCODE_NODITHER     = do not dither encoded values
 *  SGILOGENCODE_RANDITHER    = apply random dithering during encoding
 *
 * The default value of this tag is SGILOGENCODE_NODITHER for
 * COMPRESSION_SGILOG to maximize run-length encoding and
 * SGILOGENCODE_RANDITHER for COMPRESSION_SGILOG24 to turn
 * quantization errors into noise.
 */

#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <math.h>

/*
 * State block for each open TIFF
 * file using LogLuv compression/decompression.
 */
typedef	struct logLuvState LogLuvState;

struct logLuvState {
	int			user_datafmt;	/* user data format */
	int			encode_meth;	/* encoding method */
	int			pixel_size;	/* bytes per pixel */

	tidata_t*		tbuf;		/* translation buffer */
	int			tbuflen;	/* buffer length */
	void (*tfunc)(LogLuvState*, tidata_t, int);

	TIFFVSetMethod		vgetparent;	/* super-class method */
	TIFFVSetMethod		vsetparent;	/* super-class method */
};

#define	DecoderState(tif)	((LogLuvState*) (tif)->tif_data)
#define	EncoderState(tif)	((LogLuvState*) (tif)->tif_data)

#define N(a)   (sizeof(a)/sizeof(a[0]))
#define SGILOGDATAFMT_UNKNOWN	-1

#define MINRUN		4	/* minimum run length */

/*
 * Decode a string of 16-bit gray pixels.
 */
static int
LogL16Decode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
	LogLuvState* sp = DecoderState(tif);
	int shft, i, npixels;
	u_char* bp;
	int16* tp;
	int16 b;
	int cc, rc;

	assert(s == 0);
	assert(sp != NULL);

	npixels = occ / sp->pixel_size;

	if (sp->user_datafmt == SGILOGDATAFMT_16BIT)
		tp = (int16*) op;
	else {
		assert(sp->tbuflen >= npixels);
		tp = (int16*) sp->tbuf;
	}
	_TIFFmemset((tdata_t) tp, 0, npixels*sizeof (tp[0]));

	bp = (u_char*) tif->tif_rawcp;
	cc = tif->tif_rawcc;
					/* get each byte string */
	for (shft = 2*8; (shft -= 8) >= 0; ) {
		for (i = 0; i < npixels && cc > 0; )
			if (*bp >= 128) {		/* run */
				rc = *bp++ + (2-128);
				b = (int16)*bp++ << shft;
				cc -= 2;
				while (rc--)
					tp[i++] |= b;
			} else {			/* non-run */
				rc = *bp++;		/* nul is noop */
				while (--cc && rc--)
					tp[i++] |= (int16)*bp++ << shft;
			}
		if (i != npixels) {
			TIFFError(tif->tif_name,
		"LogL16Decode: Not enough data at row %d (short %d pixels)",
			    tif->tif_row, npixels - i);
			tif->tif_rawcp = (tidata_t) bp;
			tif->tif_rawcc = cc;
			return (0);
		}
	}
	(*sp->tfunc)(sp, op, npixels);
	tif->tif_rawcp = (tidata_t) bp;
	tif->tif_rawcc = cc;
	return (1);
}

/*
 * Decode a string of 24-bit pixels.
 */
static int
LogLuvDecode24(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
	LogLuvState* sp = DecoderState(tif);
	int cc, i, npixels;
	u_char* bp;
	uint32* tp;

	assert(s == 0);
	assert(sp != NULL);

	npixels = occ / sp->pixel_size;

	if (sp->user_datafmt == SGILOGDATAFMT_RAW)
		tp = (uint32 *)op;
	else {
		assert(sp->tbuflen >= npixels);
		tp = (uint32 *) sp->tbuf;
	}
					/* copy to array of uint32 */
	bp = (u_char*) tif->tif_rawcp;
	cc = tif->tif_rawcc;
	for (i = 0; i < npixels && cc > 0; i++) {
		tp[i] = bp[0] << 16 | bp[1] << 8 | bp[2];
		bp += 3;
		cc -= 3;
	}
	tif->tif_rawcp = (tidata_t) bp;
	tif->tif_rawcc = cc;
	if (i != npixels) {
		TIFFError(tif->tif_name,
	    "LogLuvDecode24: Not enough data at row %d (short %d pixels)",
		    tif->tif_row, npixels - i);
		return (0);
	}
	(*sp->tfunc)(sp, op, npixels);
	return (1);
}

/*
 * Decode a string of 32-bit pixels.
 */
static int
LogLuvDecode32(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
{
	LogLuvState* sp;
	int shft, i, npixels;
	u_char* bp;
	uint32* tp;
	uint32 b;
	int cc, rc;

	assert(s == 0);
	sp = DecoderState(tif);
	assert(sp != NULL);

	npixels = occ / sp->pixel_size;

	if (sp->user_datafmt == SGILOGDATAFMT_RAW)
		tp = (uint32*) op;
	else {
		assert(sp->tbuflen >= npixels);
		tp = (uint32*) sp->tbuf;
	}
	_TIFFmemset((tdata_t) tp, 0, npixels*sizeof (tp[0]));

	bp = (u_char*) tif->tif_rawcp;
	cc = tif->tif_rawcc;
					/* get each byte string */
	for (shft = 4*8; (shft -= 8) >= 0; ) {
		for (i = 0; i < npixels && cc > 0; )
			if (*bp >= 128) {		/* run */
				rc = *bp++ + (2-128);
				b = (uint32)*bp++ << shft;
				cc -= 2;
				while (rc--)
					tp[i++] |= b;
			} else {			/* non-run */
				rc = *bp++;		/* nul is noop */
				while (--cc && rc--)
					tp[i++] |= (uint32)*bp++ << shft;
			}
		if (i != npixels) {
			TIFFError(tif->tif_name,
		"LogLuvDecode32: Not enough data at row %d (short %d pixels)",
			    tif->tif_row, npixels - i);
			tif->tif_rawcp = (tidata_t) bp;
			tif->tif_rawcc = cc;
			return (0);
		}
	}
	(*sp->tfunc)(sp, op, npixels);
	tif->tif_rawcp = (tidata_t) bp;
	tif->tif_rawcc = cc;
	return (1);
}

/*
 * Decode a strip of pixels.  We break it into rows to
 * maintain synchrony with the encode algorithm, which
 * is row by row.
 */
static int
LogLuvDecodeStrip(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	tsize_t rowlen = TIFFScanlineSize(tif);

	assert(cc%rowlen == 0);
	while (cc && (*tif->tif_decoderow)(tif, bp, rowlen, s))
		bp += rowlen, cc -= rowlen;
	return (cc == 0);
}

/*
 * Decode a tile of pixels.  We break it into rows to
 * maintain synchrony with the encode algorithm, which
 * is row by row.
 */
static int
LogLuvDecodeTile(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	tsize_t rowlen = TIFFTileRowSize(tif);

	assert(cc%rowlen == 0);
	while (cc && (*tif->tif_decoderow)(tif, bp, rowlen, s))
		bp += rowlen, cc -= rowlen;
	return (cc == 0);
}

/*
 * Encode a row of 16-bit pixels.
 */
static int
LogL16Encode(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	LogLuvState* sp = EncoderState(tif);
	int shft, i, j, npixels;
	tidata_t op;
	int16* tp;
	int16 b;
	int occ, rc=0, mask, beg;

	assert(s == 0);
	assert(sp != NULL);
	npixels = cc / sp->pixel_size;

	if (sp->user_datafmt == SGILOGDATAFMT_16BIT)
		tp = (int16*) bp;
	else {
		tp = (int16*) sp->tbuf;
		assert(sp->tbuflen >= npixels);
		(*sp->tfunc)(sp, bp, npixels);
	}
					/* compress each byte string */
	op = tif->tif_rawcp;
	occ = tif->tif_rawdatasize - tif->tif_rawcc;
	for (shft = 2*8; (shft -= 8) >= 0; )
		for (i = 0; i < npixels; i += rc) {
			if (occ < 4) {
				tif->tif_rawcp = op;
				tif->tif_rawcc = tif->tif_rawdatasize - occ;
				if (!TIFFFlushData1(tif))
					return (-1);
				op = tif->tif_rawcp;
				occ = tif->tif_rawdatasize - tif->tif_rawcc;
			}
			mask = 0xff << shft;		/* find next run */
			for (beg = i; beg < npixels; beg += rc) {
				b = tp[beg] & mask;
				rc = 1;
				while (rc < 127+2 && beg+rc < npixels &&
						(tp[beg+rc] & mask) == b)
					rc++;
				if (rc >= MINRUN)
					break;		/* long enough */
			}
			if (beg-i > 1 && beg-i < MINRUN) {
				b = tp[i] & mask;	/* check short run */
				j = i+1;
				while ((tp[j++] & mask) == b)
					if (j == beg) {
						*op++ = 128-2+j-i;
						*op++ = b >> shft;
						occ -= 2;
						i = beg;
						break;
					}
			}
			while (i < beg) {		/* write out non-run */
				if ((j = beg-i) > 127) j = 127;
				if (occ < j+3) {
					tif->tif_rawcp = op;
					tif->tif_rawcc = tif->tif_rawdatasize - occ;
					if (!TIFFFlushData1(tif))
						return (-1);
					op = tif->tif_rawcp;
					occ = tif->tif_rawdatasize - tif->tif_rawcc;
				}
				*op++ = j; occ--;
				while (j--) {
					*op++ = tp[i++] >> shft & 0xff;
					occ--;
				}
			}
			if (rc >= MINRUN) {		/* write out run */
				*op++ = 128-2+rc;
				*op++ = tp[beg] >> shft & 0xff;
				occ -= 2;
			} else
				rc = 0;
		}
	tif->tif_rawcp = op;
	tif->tif_rawcc = tif->tif_rawdatasize - occ;

	return (0);
}

/*
 * Encode a row of 24-bit pixels.
 */
static int
LogLuvEncode24(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	LogLuvState* sp = EncoderState(tif);
	int i, npixels, occ;
	tidata_t op;
	uint32* tp;

	assert(s == 0);
	assert(sp != NULL);
	npixels = cc / sp->pixel_size;

	if (sp->user_datafmt == SGILOGDATAFMT_RAW)
		tp = (uint32*) bp;
	else {
		tp = (uint32*) sp->tbuf;
		assert(sp->tbuflen >= npixels);
		(*sp->tfunc)(sp, bp, npixels);
	}
					/* write out encoded pixels */
	op = tif->tif_rawcp;
	occ = tif->tif_rawdatasize - tif->tif_rawcc;
	for (i = npixels; i--; ) {
		if (occ < 3) {
			tif->tif_rawcp = op;
			tif->tif_rawcc = tif->tif_rawdatasize - occ;
			if (!TIFFFlushData1(tif))
				return (-1);
			op = tif->tif_rawcp;
			occ = tif->tif_rawdatasize - tif->tif_rawcc;
		}
		*op++ = (tidataval_t)(*tp >> 16);
		*op++ = (tidataval_t)(*tp >> 8 & 0xff);
		*op++ = (tidataval_t)(*tp++ & 0xff);
		occ -= 3;
	}
	tif->tif_rawcp = op;
	tif->tif_rawcc = tif->tif_rawdatasize - occ;

	return (0);
}

/*
 * Encode a row of 32-bit pixels.
 */
static int
LogLuvEncode32(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
	LogLuvState* sp = EncoderState(tif);
	int shft, i, j, npixels;
	tidata_t op;
	uint32* tp;
	uint32 b;
	int occ, rc=0, mask, beg;

	assert(s == 0);
	assert(sp != NULL);

	npixels = cc / sp->pixel_size;

	if (sp->user_datafmt == SGILOGDATAFMT_RAW)
		tp = (uint32*) bp;
	else {
		tp = (uint32*) sp->tbuf;
		assert(sp->tbuflen >= npixels);
		(*sp->tfunc)(sp, bp, npixels);
	}
					/* compress each byte string */
	op = tif->tif_rawcp;
	occ = tif->tif_rawdatasize - tif->tif_rawcc;