tif_jpeg.c

来自「支持各种栅格图像和矢量图像读取的库」· C语言 代码 · 共 2,014 行 · 第 1/4 页

				int n = sp->cinfo.d.max_v_samp_factor * DCTSIZE;
				if (TIFFjpeg_read_raw_data(sp, sp->ds_buffer, n) != n)
					return (0);
				sp->scancount = 0;
			}
			/*
			 * Fastest way to unseparate data is to make one pass
			 * over the scanline for each row of each component.
			 */
			clumpoffset = 0;    /* first sample in clump */
			for (ci = 0, compptr = sp->cinfo.d.comp_info;
			    ci < sp->cinfo.d.num_components;
			    ci++, compptr++) {
				int hsamp = compptr->h_samp_factor;
				int vsamp = compptr->v_samp_factor;
				int ypos;

				for (ypos = 0; ypos < vsamp; ypos++) {
					JSAMPLE *inptr = sp->ds_buffer[ci][sp->scancount*vsamp + ypos];
#ifdef JPEG_LIB_MK1
					JSAMPLE *outptr = (JSAMPLE*)tmpbuf + clumpoffset;
#else
					JSAMPLE *outptr = (JSAMPLE*)buf + clumpoffset;
#endif
					JDIMENSION nclump;

					if (hsamp == 1) {
						/* fast path for at least Cb and Cr */
						for (nclump = clumps_per_line; nclump-- > 0; ) {
							outptr[0] = *inptr++;
							outptr += samples_per_clump;
						}
					} else {
						int xpos;

			/* general case */
						for (nclump = clumps_per_line; nclump-- > 0; ) {
							for (xpos = 0; xpos < hsamp; xpos++)
								outptr[xpos] = *inptr++;
							outptr += samples_per_clump;
						}
					}
					clumpoffset += hsamp;
				}
			}

#ifdef JPEG_LIB_MK1
			{
				if (sp->cinfo.d.data_precision == 8)
				{
					int i=0;
					int len = sp->cinfo.d.output_width * sp->cinfo.d.num_components;
					for (i=0; i<len; i++)
					{
						((unsigned char*)buf)[i] = tmpbuf[i] & 0xff;
					}
				}
				else
				{         // 12-bit
					int value_pairs = (sp->cinfo.d.output_width
					    * sp->cinfo.d.num_components) / 2;
					int iPair;
					for( iPair = 0; iPair < value_pairs; iPair++ )
					{
						unsigned char *out_ptr = ((unsigned char *) buf) + iPair * 3;
						JSAMPLE *in_ptr = tmpbuf + iPair * 2;
						out_ptr[0] = (in_ptr[0] & 0xff0) >> 4;
						out_ptr[1] = ((in_ptr[0] & 0xf) << 4)
						    | ((in_ptr[1] & 0xf00) >> 8);
						out_ptr[2] = ((in_ptr[1] & 0xff) >> 0);
					}
				}
			}
#endif

			sp->scancount ++;
			tif->tif_row += sp->v_sampling;
			/* increment/decrement of buf and cc is still incorrect, but should not matter
			 * TODO: resolve this */
			buf += sp->bytesperline;
			cc -= sp->bytesperline;
			nrows -= sp->v_sampling;
		} while (nrows > 0);

#ifdef JPEG_LIB_MK1
		_TIFFfree(tmpbuf);
#endif

	}

	/* Close down the decompressor if done. */
	return sp->cinfo.d.output_scanline < sp->cinfo.d.output_height
	    || TIFFjpeg_finish_decompress(sp);
}


/*
 * JPEG Encoding.
 */

static void
unsuppress_quant_table (JPEGState* sp, int tblno)
{
	JQUANT_TBL* qtbl;

	if ((qtbl = sp->cinfo.c.quant_tbl_ptrs[tblno]) != NULL)
		qtbl->sent_table = FALSE;
}

static void
unsuppress_huff_table (JPEGState* sp, int tblno)
{
	JHUFF_TBL* htbl;

	if ((htbl = sp->cinfo.c.dc_huff_tbl_ptrs[tblno]) != NULL)
		htbl->sent_table = FALSE;
	if ((htbl = sp->cinfo.c.ac_huff_tbl_ptrs[tblno]) != NULL)
		htbl->sent_table = FALSE;
}

static int
prepare_JPEGTables(TIFF* tif)
{
	JPEGState* sp = JState(tif);

        JPEGInitializeLibJPEG( tif, 0, 0 );

	/* Initialize quant tables for current quality setting */
	if (!TIFFjpeg_set_quality(sp, sp->jpegquality, FALSE))
		return (0);
	/* Mark only the tables we want for output */
	/* NB: chrominance tables are currently used only with YCbCr */
	if (!TIFFjpeg_suppress_tables(sp, TRUE))
		return (0);
	if (sp->jpegtablesmode & JPEGTABLESMODE_QUANT) {
		unsuppress_quant_table(sp, 0);
		if (sp->photometric == PHOTOMETRIC_YCBCR)
			unsuppress_quant_table(sp, 1);
	}
	if (sp->jpegtablesmode & JPEGTABLESMODE_HUFF) {
		unsuppress_huff_table(sp, 0);
		if (sp->photometric == PHOTOMETRIC_YCBCR)
			unsuppress_huff_table(sp, 1);
	}
	/* Direct libjpeg output into jpegtables */
	if (!TIFFjpeg_tables_dest(sp, tif))
		return (0);
	/* Emit tables-only datastream */
	if (!TIFFjpeg_write_tables(sp))
		return (0);

	return (1);
}

static int
JPEGSetupEncode(TIFF* tif)
{
	JPEGState* sp = JState(tif);
	TIFFDirectory *td = &tif->tif_dir;
	static const char module[] = "JPEGSetupEncode";

        JPEGInitializeLibJPEG( tif, 1, 0 );

	assert(sp != NULL);
	assert(!sp->cinfo.comm.is_decompressor);

	/*
	 * Initialize all JPEG parameters to default values.
	 * Note that jpeg_set_defaults needs legal values for
	 * in_color_space and input_components.
	 */
	sp->cinfo.c.in_color_space = JCS_UNKNOWN;
	sp->cinfo.c.input_components = 1;
	if (!TIFFjpeg_set_defaults(sp))
		return (0);
	/* Set per-file parameters */
	sp->photometric = td->td_photometric;
	switch (sp->photometric) {
	case PHOTOMETRIC_YCBCR:
		sp->h_sampling = td->td_ycbcrsubsampling[0];
		sp->v_sampling = td->td_ycbcrsubsampling[1];
		/*
		 * A ReferenceBlackWhite field *must* be present since the
		 * default value is inappropriate for YCbCr.  Fill in the
		 * proper value if application didn't set it.
		 */
		{
			float *ref;
			if (!TIFFGetField(tif, TIFFTAG_REFERENCEBLACKWHITE,
					  &ref)) {
				float refbw[6];
				long top = 1L << td->td_bitspersample;
				refbw[0] = 0;
				refbw[1] = (float)(top-1L);
				refbw[2] = (float)(top>>1);
				refbw[3] = refbw[1];
				refbw[4] = refbw[2];
				refbw[5] = refbw[1];
				TIFFSetField(tif, TIFFTAG_REFERENCEBLACKWHITE,
					     refbw);
			}
		}
		break;
	case PHOTOMETRIC_PALETTE:		/* disallowed by Tech Note */
	case PHOTOMETRIC_MASK:
		TIFFErrorExt(tif->tif_clientdata, module,
			  "PhotometricInterpretation %d not allowed for JPEG",
			  (int) sp->photometric);
		return (0);
	default:
		/* TIFF 6.0 forbids subsampling of all other color spaces */
		sp->h_sampling = 1;
		sp->v_sampling = 1;
		break;
	}

	/* Verify miscellaneous parameters */

	/*
	 * This would need work if libtiff ever supports different
	 * depths for different components, or if libjpeg ever supports
	 * run-time selection of depth.  Neither is imminent.
	 */
#ifdef JPEG_LIB_MK1
        /* BITS_IN_JSAMPLE now permits 8 and 12 --- dgilbert */
	if (td->td_bitspersample != 8 && td->td_bitspersample != 12) 
#else
	if (td->td_bitspersample != BITS_IN_JSAMPLE )
#endif
	{
		TIFFErrorExt(tif->tif_clientdata, module, "BitsPerSample %d not allowed for JPEG",
			  (int) td->td_bitspersample);
		return (0);
	}
	sp->cinfo.c.data_precision = td->td_bitspersample;
#ifdef JPEG_LIB_MK1
        sp->cinfo.c.bits_in_jsample = td->td_bitspersample;
#endif
	if (isTiled(tif)) {
		if ((td->td_tilelength % (sp->v_sampling * DCTSIZE)) != 0) {
			TIFFErrorExt(tif->tif_clientdata, module,
				  "JPEG tile height must be multiple of %d",
				  sp->v_sampling * DCTSIZE);
			return (0);
		}
		if ((td->td_tilewidth % (sp->h_sampling * DCTSIZE)) != 0) {
			TIFFErrorExt(tif->tif_clientdata, module,
				  "JPEG tile width must be multiple of %d",
				  sp->h_sampling * DCTSIZE);
			return (0);
		}
	} else {
		if (td->td_rowsperstrip < td->td_imagelength &&
		    (td->td_rowsperstrip % (sp->v_sampling * DCTSIZE)) != 0) {
			TIFFErrorExt(tif->tif_clientdata, module,
				  "RowsPerStrip must be multiple of %d for JPEG",
				  sp->v_sampling * DCTSIZE);
			return (0);
		}
	}

	/* Create a JPEGTables field if appropriate */
	if (sp->jpegtablesmode & (JPEGTABLESMODE_QUANT|JPEGTABLESMODE_HUFF)) {
		if (!prepare_JPEGTables(tif))
			return (0);
		/* Mark the field present */
		/* Can't use TIFFSetField since BEENWRITING is already set! */
		TIFFSetFieldBit(tif, FIELD_JPEGTABLES);
		tif->tif_flags |= TIFF_DIRTYDIRECT;
	} else {
		/* We do not support application-supplied JPEGTables, */
		/* so mark the field not present */
		TIFFClrFieldBit(tif, FIELD_JPEGTABLES);
	}

	/* Direct libjpeg output to libtiff's output buffer */
	TIFFjpeg_data_dest(sp, tif);

	return (1);
}

/*
 * Set encoding state at the start of a strip or tile.
 */
static int
JPEGPreEncode(TIFF* tif, tsample_t s)
{
	JPEGState *sp = JState(tif);
	TIFFDirectory *td = &tif->tif_dir;
	static const char module[] = "JPEGPreEncode";
	uint32 segment_width, segment_height;
	int downsampled_input;

	assert(sp != NULL);
	assert(!sp->cinfo.comm.is_decompressor);
	/*
	 * Set encoding parameters for this strip/tile.
	 */
	if (isTiled(tif)) {
		segment_width = td->td_tilewidth;
		segment_height = td->td_tilelength;
		sp->bytesperline = TIFFTileRowSize(tif);
	} else {
		segment_width = td->td_imagewidth;
		segment_height = td->td_imagelength - tif->tif_row;
		if (segment_height > td->td_rowsperstrip)
			segment_height = td->td_rowsperstrip;
		sp->bytesperline = TIFFOldScanlineSize(tif);
	}
	if (td->td_planarconfig == PLANARCONFIG_SEPARATE && s > 0) {
		/* for PC 2, scale down the strip/tile size
		 * to match a downsampled component
		 */
		segment_width = TIFFhowmany(segment_width, sp->h_sampling);
		segment_height = TIFFhowmany(segment_height, sp->v_sampling);
	}
	if (segment_width > 65535 || segment_height > 65535) {
		TIFFErrorExt(tif->tif_clientdata, module, "Strip/tile too large for JPEG");
		return (0);
	}
	sp->cinfo.c.image_width = segment_width;
	sp->cinfo.c.image_height = segment_height;
	downsampled_input = FALSE;
	if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
		sp->cinfo.c.input_components = td->td_samplesperpixel;
		if (sp->photometric == PHOTOMETRIC_YCBCR) {
			if (sp->jpegcolormode == JPEGCOLORMODE_RGB) {
				sp->cinfo.c.in_color_space = JCS_RGB;
			} else {
				sp->cinfo.c.in_color_space = JCS_YCbCr;
				if (sp->h_sampling != 1 || sp->v_sampling != 1)
					downsampled_input = TRUE;
			}
			if (!TIFFjpeg_set_colorspace(sp, JCS_YCbCr))
				return (0);
			/*
			 * Set Y sampling factors;
			 * we assume jpeg_set_colorspace() set the rest to 1
			 */
			sp->cinfo.c.comp_info[0].h_samp_factor = sp->h_sampling;
			sp->cinfo.c.comp_info[0].v_samp_factor = sp->v_sampling;
		} else {
			sp->cinfo.c.in_color_space = JCS_UNKNOWN;
			if (!TIFFjpeg_set_colorspace(sp, JCS_UNKNOWN))
				return (0);
			/* jpeg_set_colorspace set all sampling factors to 1 */
		}
	} else {
		sp->cinfo.c.input_components = 1;
		sp->cinfo.c.in_color_space = JCS_UNKNOWN;
		if (!TIFFjpeg_set_colorspace(sp, JCS_UNKNOWN))
			return (0);
		sp->cinfo.c.comp_info[0].component_id = s;
		/* jpeg_set_colorspace() set sampling factors to 1 */
		if (sp->photometric == PHOTOMETRIC_YCBCR && s > 0) {
			sp->cinfo.c.comp_info[0].quant_tbl_no = 1;
			sp->cinfo.c.comp_info[0].dc_tbl_no = 1;
			sp->cinfo.c.comp_info[0].ac_tbl_no = 1;
		}
	}
	/* ensure libjpeg won't write any extraneous markers */
	sp->cinfo.c.write_JFIF_header = FALSE;
	sp->cinfo.c.write_Adobe_marker = FALSE;
	/* set up table handling correctly */
	if (! (sp->jpegtablesmode & JPEGTABLESMODE_QUANT)) {
		if (!TIFFjpeg_set_quality(sp, sp->jpegquality, FALSE))
			return (0);
		unsuppress_quant_table(sp, 0);
		unsuppress_quant_table(sp, 1);
	}
	if (sp->jpegtablesmode & JPEGTABLESMODE_HUFF)
		sp->cinfo.c.optimize_coding = FALSE;
	else
		sp->cinfo.c.optimize_coding = TRUE;
	if (downsampled_input) {
		/* Need to use raw-data interface to libjpeg */
		sp->cinfo.c.raw_data_in = TRUE;
		tif->tif_encoderow = JPEGEncodeRaw;
		tif->tif_encodestrip = JPEGEncodeRaw;
		tif->tif_encodetile = JPEGEncodeRaw;
	} else {
		/* Use normal interface to libjpeg */
		sp->cinfo.c.raw_data_in = FALSE;
		tif->tif_encoderow = JPEGEncode;
		tif->tif_encodestrip = JPEGEncode;
		tif->tif_encodetile = JPEGEncode;
	}
	/* Start JPEG compressor */
	if (!TIFFjpeg_start_compress(sp, FALSE))
		return (0);
	/* Allocate downsampled-data buffers if needed */
	if (downsampled_input) {
		if (!alloc_downsampled_buffers(tif, sp->cinfo.c.comp_info,
					       sp->cinfo.c.num_components))
			return (0);
	}
	sp->scancount = 0;

	return (1);
}

/*
 * Encode a chunk of pixels.
 * "Standard" case: incoming data is not downsampled.
 */
static int
JPEGEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
{
	JPEGState *sp = JState(tif);
	tsize_t nrows;
	JSAMPROW bufptr[1];

	(void) s;
	assert(sp != NULL);
	/* data is expected to be supplied in multiples of a scanline */
	nrows = cc / sp->bytesperline;
	if (cc % sp->bytesperline)
		TIFFWarningExt(tif->tif_clientdata, tif->tif_name, "fractional scanline discarded");

	while (nrows-- > 0) {
		bufptr[0] = (JSAMPROW) buf;
		if (TIFFjpeg_write_scanlines(sp, bufptr, 1) != 1)
			return (0);
		if (nrows > 0)
			tif->tif_row++;
		buf += sp->bytesperline;
	}
	return (1);
}

/*
 * Encode a chunk of pixels.
 * Incoming data is expected to be downsampled per sampling factors.
 */
static int
JPEGEncodeRaw(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
{
	JPEGState *sp = JState(tif);
	JSAMPLE* inptr;
	JSAMPLE* outptr;
	tsize_t nrows;
	JDIMENSION clumps_per_line, nclump;
	int clumpoffset, ci, xpos, ypos;
	jpeg_component_info* compptr;
	int samples_per_clump = sp->samplesperclump;
	tsize_t bytesperclumpline;

	(void) s;
	assert(sp != NULL);
	/* data is expected to be supplied in multiples of a clumpline */
	/* a clumpline is equivalent to v_sampling desubsampled scanlines */
	/* TODO: the following calculation of bytesperclumpline, should substitute calculation of sp->bytesperline, except that it is per v_sampling lines */
	bytesperclumpline = (((sp->cinfo.c.image_width+sp->h_sampling-1)/sp->h_sampling)
			     *(sp->h_sampling*sp->v_sampling+2)*sp->cinfo.c.data_precision+7)
			    /8;

	nrows = ( cc / bytesperclumpline ) * sp->v_sampling;
	if (cc % bytesperclumpline)
		TIFFWarningExt(tif->tif_clientdata, tif->tif_name, "fractional scanline discarded");

	/* Cb,Cr both have sampling factors 1, so this is correct */
	clumps_per_line = sp->cinfo.c.comp_info[1].downsampled_width;

	while (nrows > 0) {
		/*
		 * Fastest way to separate the data is to make one pass
		 * over the scanline for each row of each component.
		 */
		clumpoffset = 0;		/* first sample in clump */
		for (ci = 0, compptr = sp->cinfo.c.comp_info;
		     ci < sp->cinfo.c.num_components;
		     ci++, compptr++) {
		    int hsamp = compptr->h_samp_factor;
		    int vsamp = compptr->v_samp_factor;
		    int padding = (int) (compptr->width_in_blocks * DCTSIZE -
					 clumps_per_line * hsamp);
		    for (ypos = 0; ypos < vsamp; ypos++) {
			inptr = ((JSAMPLE*) buf) + clumpoffset;
			outptr = sp->ds_buffer[ci][sp->scancount*vsamp + ypos];
			if (hsamp == 1) {
			    /* fast path for at least Cb and Cr */
			    for (nclump = clumps_per_line; nclump-- > 0; ) {
				*outptr++ = inptr[0];
				inptr += samples_per_clump;
			    }
			} else {
			    /* general case */
			    for (nclump = clumps_per_line; nclump-- > 0; ) {
				for (xpos = 0; xpos < hsamp; xpos++)
				    *outptr++ = inptr[xpos];
				inptr += samples_per_clump;
			    }
			}
			/* pad each scanline as needed */
			for (xpos = 0; xpos < padding; xpos++) {
			    *outptr = outptr[-1];
			    outptr++;
			}
			clumpoffset += hsamp;
		    }
		}
		sp->scancount++;
		if (sp->scancount >= DCTSIZE) {
			int n = sp->cinfo.c.max_v_samp_factor * DCTSIZE;