jp2_enc.c

用C语言实现的JPEG编码

	case JAS_CLRSPC_SYCBCR:
	case JAS_CLRSPC_SGRAY:
		colr->method = JP2_COLR_ENUM;
		colr->csid = clrspctojp2(jas_image_clrspc(image));
		colr->pri = JP2_COLR_PRI;
		colr->approx = 0;
		break;
	default:
		colr->method = JP2_COLR_ICC;
		colr->pri = JP2_COLR_PRI;
		colr->approx = 0;
		iccprof = jas_iccprof_createfromcmprof(jas_image_cmprof(image));
		assert(iccprof);
		iccstream = jas_stream_memopen(0, 0);
		assert(iccstream);
		if (jas_iccprof_save(iccprof, iccstream))
			abort();
		if ((pos = jas_stream_tell(iccstream)) < 0)
			abort();
		colr->iccplen = pos;
		colr->iccp = jas_malloc(pos);
		assert(colr->iccp);
		jas_stream_rewind(iccstream);
		if (jas_stream_read(iccstream, colr->iccp, colr->iccplen) != colr->iccplen)
			abort();
		jas_stream_close(iccstream);
		jas_iccprof_destroy(iccprof);
		break;
	}
	if (jp2_box_put(box, tmpstream)) {
		goto error;
	}
	jp2_box_destroy(box);
	box = 0;

	needcdef = 1;
	switch (jas_clrspc_fam(jas_image_clrspc(image))) {
	case JAS_CLRSPC_FAM_RGB:
		if (jas_image_cmpttype(image, 0) ==
		  JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_RGB_R) &&
		  jas_image_cmpttype(image, 1) ==
		  JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_RGB_G) &&
		  jas_image_cmpttype(image, 2) ==
		  JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_RGB_B))
			needcdef = 0;
		break;
	case JAS_CLRSPC_FAM_YCBCR:
		if (jas_image_cmpttype(image, 0) ==
		  JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_YCBCR_Y) &&
		  jas_image_cmpttype(image, 1) ==
		  JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_YCBCR_CB) &&
		  jas_image_cmpttype(image, 2) ==
		  JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_YCBCR_CR))
			needcdef = 0;
		break;
	case JAS_CLRSPC_FAM_GRAY:
		if (jas_image_cmpttype(image, 0) ==
		  JAS_IMAGE_CT_COLOR(JAS_IMAGE_CT_GRAY_Y))
			needcdef = 0;
		break;
	default:
		abort();
		break;
	}

	if (needcdef) {
		if (!(box = jp2_box_create(JP2_BOX_CDEF))) {
			goto error;
		}
		cdef = &box->data.cdef;
		cdef->numchans = jas_image_numcmpts(image);
		cdef->ents = jas_malloc(cdef->numchans * sizeof(jp2_cdefchan_t));
		for (i = 0; i < jas_image_numcmpts(image); ++i) {
			cdefchanent = &cdef->ents[i];
			cdefchanent->channo = i;
			typeasoc = jp2_gettypeasoc(jas_image_clrspc(image), jas_image_cmpttype(image, i));
			cdefchanent->type = typeasoc >> 16;
			cdefchanent->assoc = typeasoc & 0x7fff;
		}
		if (jp2_box_put(box, tmpstream)) {
			goto error;
		}
		jp2_box_destroy(box);
		box = 0;
	}

	/* Determine the total length of the JP2 header box. */

	len = jas_stream_tell(tmpstream);
	jas_stream_rewind(tmpstream);

	/*
	 * Output the JP2 header box and all of the boxes which it contains.
	 */

	if (!(box = jp2_box_create(JP2_BOX_JP2H))) {
		goto error;
	}
	box->len = len + JP2_BOX_HDRLEN;
	if (jp2_box_put(box, out)) {
		goto error;
	}
	jp2_box_destroy(box);
	box = 0;

	if (jas_stream_copy(out, tmpstream, len)) {
		goto error;
	}

	jas_stream_close(tmpstream);
	tmpstream = 0;

	return 0;
	abort();

error:

	if (box) {
		jp2_box_destroy(box);
	}
	if (tmpstream) {
		jas_stream_close(tmpstream);
	}
	return -1;
}

int jp2_write_codestream(jas_image_t *image, jas_stream_t *out, char *optstr)
{
	jp2_box_t *box;
	char buf[4096];
	uint_fast32_t overhead;

	/*
	 * Output the contiguous code stream box.
	 */

	if (!(box = jp2_box_create(JP2_BOX_JP2C))) {
		goto error;
	}
	box->len = 0;
	if (jp2_box_put(box, out)) {
		goto error;
	}
	jp2_box_destroy(box);
	box = 0;

	/* Output the JPEG-2000 code stream. */

	overhead = jas_stream_getrwcount(out);
	sprintf(buf, "%s\n_jp2overhead=%lu\n", (optstr ? optstr : ""),
	  (unsigned long) overhead);

	if (jpc_encode(image, out, buf)) {
		goto error;
	}

	return 0;
	abort();

error:

	if (box) {
		jp2_box_destroy(box);
	}
	return -1;
}

int jp2_encode(jas_image_t *image, jas_stream_t *out, char *optstr)
{
	if (jp2_write_header(image, out) < 0)
		return -1;
	if (jp2_write_codestream(image, out, optstr) < 0)
		return -1;

	return 0;
}

int jp2_encode_uuid(jas_image_t *image, jas_stream_t *out,
		    char *optstr, jp2_box_t *uuid)
{
	if (jp2_write_header(image, out) < 0)
		return -1;
	if (uuid) {
		if (jp2_box_put(uuid, out))
			return -1;
	}
	if (jp2_write_codestream(image, out, optstr) < 0)
		return -1;

	return 0;
}

static uint_fast32_t jp2_gettypeasoc(int colorspace, int ctype)
{
	int type;
	int asoc;

	if (ctype & JAS_IMAGE_CT_OPACITY) {
		type = JP2_CDEF_TYPE_OPACITY;
		asoc = JP2_CDEF_ASOC_ALL;
		goto done;
	}

	type = JP2_CDEF_TYPE_UNSPEC;
	asoc = JP2_CDEF_ASOC_NONE;
	switch (jas_clrspc_fam(colorspace)) {
	case JAS_CLRSPC_FAM_RGB:
		switch (JAS_IMAGE_CT_COLOR(ctype)) {
		case JAS_IMAGE_CT_RGB_R:
			type = JP2_CDEF_TYPE_COLOR;
			asoc = JP2_CDEF_RGB_R;
			break;
		case JAS_IMAGE_CT_RGB_G:
			type = JP2_CDEF_TYPE_COLOR;
			asoc = JP2_CDEF_RGB_G;
			break;
		case JAS_IMAGE_CT_RGB_B:
			type = JP2_CDEF_TYPE_COLOR;
			asoc = JP2_CDEF_RGB_B;
			break;
		}
		break;
	case JAS_CLRSPC_FAM_YCBCR:
		switch (JAS_IMAGE_CT_COLOR(ctype)) {
		case JAS_IMAGE_CT_YCBCR_Y:
			type = JP2_CDEF_TYPE_COLOR;
			asoc = JP2_CDEF_YCBCR_Y;
			break;
		case JAS_IMAGE_CT_YCBCR_CB:
			type = JP2_CDEF_TYPE_COLOR;
			asoc = JP2_CDEF_YCBCR_CB;
			break;
		case JAS_IMAGE_CT_YCBCR_CR:
			type = JP2_CDEF_TYPE_COLOR;
			asoc = JP2_CDEF_YCBCR_CR;
			break;
		}
		break;
	case JAS_CLRSPC_FAM_GRAY:
		type = JP2_CDEF_TYPE_COLOR;
		asoc = JP2_CDEF_GRAY_Y;
		break;
	}

done:
	return (type << 16) | asoc;
}

static int clrspctojp2(jas_clrspc_t clrspc)
{
	switch (clrspc) {
	case JAS_CLRSPC_SRGB:
		return JP2_COLR_SRGB;
	case JAS_CLRSPC_SYCBCR:
		return JP2_COLR_SYCC;
	case JAS_CLRSPC_SGRAY:
		return JP2_COLR_SGRAY;
	default:
		abort();
		break;
	}
}