jcparam.c

来自「用在MIPS结构的Jz47XX芯片上的ucos系统,仅供参考」· C语言 代码 · 共 474 行 · 第 1/2 页

      0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
      0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
      0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
      0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
      0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
      0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
      0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
      0xf9, 0xfa };
  
  add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0],
		 bits_dc_luminance, val_dc_luminance);
  add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0],
		 bits_ac_luminance, val_ac_luminance);
  add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1],
		 bits_dc_chrominance, val_dc_chrominance);
  add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1],
		 bits_ac_chrominance, val_ac_chrominance);
}


/*
 * Default parameter setup for compression.
 *
 * Applications that don't choose to use this routine must do their
 * own setup of all these parameters.  Alternately, you can call this
 * to establish defaults and then alter parameters selectively.  This
 * is the recommended approach since, if we add any new parameters,
 * your code will still work (they'll be set to reasonable defaults).
 */

GLOBAL(void)
jpeg_set_defaults (j_compress_ptr cinfo)
{
  int i;

  /* Safety check to ensure start_compress not called yet. */
  if (cinfo->global_state != CSTATE_START)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  /* Allocate comp_info array large enough for maximum component count.
   * Array is made permanent in case application wants to compress
   * multiple images at same param settings.
   */
  if (cinfo->comp_info == NULL)
    cinfo->comp_info = (jpeg_component_info *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
				  MAX_COMPONENTS * SIZEOF(jpeg_component_info));

  /* Initialize everything not dependent on the color space */

  cinfo->data_precision = BITS_IN_JSAMPLE;
  /* Set up two quantization tables using default quality of 75 */
  jpeg_set_quality(cinfo, 75, TRUE);
  /* Set up two Huffman tables */
  std_huff_tables(cinfo);

  /* Initialize default arithmetic coding conditioning */
  for (i = 0; i < NUM_ARITH_TBLS; i++) {
    cinfo->arith_dc_L[i] = 0;
    cinfo->arith_dc_U[i] = 1;
    cinfo->arith_ac_K[i] = 5;
  }

  /* Default is no multiple-scan output */
  cinfo->scan_info = NULL;
  cinfo->num_scans = 0;

  /* Expect normal source image, not raw downsampled data */
  cinfo->raw_data_in = FALSE;

  /* Use Huffman coding, not arithmetic coding, by default */
  cinfo->arith_code = FALSE;

  /* By default, don't do extra passes to optimize entropy coding */
  cinfo->optimize_coding = FALSE;
  /* The standard Huffman tables are only valid for 8-bit data precision.
   * If the precision is higher, force optimization on so that usable
   * tables will be computed.  This test can be removed if default tables
   * are supplied that are valid for the desired precision.
   */
  if (cinfo->data_precision > 8)
    cinfo->optimize_coding = TRUE;

  /* By default, use the simpler non-cosited sampling alignment */
  cinfo->CCIR601_sampling = FALSE;

  /* No input smoothing */
  cinfo->smoothing_factor = 0;

  /* DCT algorithm preference */
  cinfo->dct_method = JDCT_DEFAULT;

  /* No restart markers */
  cinfo->restart_interval = 0;
  cinfo->restart_in_rows = 0;

  /* Fill in default JFIF marker parameters.  Note that whether the marker
   * will actually be written is determined by jpeg_set_colorspace.
   *
   * By default, the library emits JFIF version code 1.01.
   * An application that wants to emit JFIF 1.02 extension markers should set
   * JFIF_minor_version to 2.  We could probably get away with just defaulting
   * to 1.02, but there may still be some decoders in use that will complain
   * about that; saying 1.01 should minimize compatibility problems.
   */
  cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */
  cinfo->JFIF_minor_version = 1;
  cinfo->density_unit = 0;	/* Pixel size is unknown by default */
  cinfo->X_density = 1;		/* Pixel aspect ratio is square by default */
  cinfo->Y_density = 1;

  /* Choose JPEG colorspace based on input space, set defaults accordingly */

  jpeg_default_colorspace(cinfo);
}


/*
 * Select an appropriate JPEG colorspace for in_color_space.
 */

GLOBAL(void)
jpeg_default_colorspace (j_compress_ptr cinfo)
{
  switch (cinfo->in_color_space) {
  case JCS_GRAYSCALE:
    jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
    break;
  case JCS_RGB:
    jpeg_set_colorspace(cinfo, JCS_YCbCr);
    break;
  case JCS_YCbCr:
    jpeg_set_colorspace(cinfo, JCS_YCbCr);
    break;
  case JCS_CMYK:
    jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */
    break;
  case JCS_YCCK:
    jpeg_set_colorspace(cinfo, JCS_YCCK);
    break;
  case JCS_UNKNOWN:
    jpeg_set_colorspace(cinfo, JCS_UNKNOWN);
    break;
  default:
    ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
  }
}


/*
 * Set the JPEG colorspace, and choose colorspace-dependent default values.
 */

GLOBAL(void)
jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
{
  jpeg_component_info * compptr;
  int ci;

#define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl)  \
  (compptr = &cinfo->comp_info[index], \
   compptr->component_id = (id), \
   compptr->h_samp_factor = (hsamp), \
   compptr->v_samp_factor = (vsamp), \
   compptr->quant_tbl_no = (quant), \
   compptr->dc_tbl_no = (dctbl), \
   compptr->ac_tbl_no = (actbl) )

  /* Safety check to ensure start_compress not called yet. */
  if (cinfo->global_state != CSTATE_START)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  /* For all colorspaces, we use Q and Huff tables 0 for luminance components,
   * tables 1 for chrominance components.
   */

  cinfo->jpeg_color_space = colorspace;

  cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */
  cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */

  switch (colorspace) {
  case JCS_GRAYSCALE:
    cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
    cinfo->num_components = 1;
    /* JFIF specifies component ID 1 */
    SET_COMP(0, 1, 1,1, 0, 0,0);
    break;
  case JCS_RGB:
    cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
    cinfo->num_components = 3;
    SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
    SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
    SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
    break;
  case JCS_YCbCr:
    cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
    cinfo->num_components = 3;
    /* JFIF specifies component IDs 1,2,3 */
    /* We default to 2x2 subsamples of chrominance */
    SET_COMP(0, 1, 2,2, 0, 0,0);
    SET_COMP(1, 2, 1,1, 1, 1,1);
    SET_COMP(2, 3, 1,1, 1, 1,1);
    break;
  case JCS_CMYK:
    cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
    cinfo->num_components = 4;
    SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
    SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
    SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
    SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
    break;
  case JCS_YCCK:
    cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
    cinfo->num_components = 4;
    SET_COMP(0, 1, 2,2, 0, 0,0);
    SET_COMP(1, 2, 1,1, 1, 1,1);
    SET_COMP(2, 3, 1,1, 1, 1,1);
    SET_COMP(3, 4, 2,2, 0, 0,0);
    break;
  case JCS_UNKNOWN:
    cinfo->num_components = cinfo->input_components;
    if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS)
      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
	       MAX_COMPONENTS);
    for (ci = 0; ci < cinfo->num_components; ci++) {
      SET_COMP(ci, ci, 1,1, 0, 0,0);
    }
    break;
  default:
    ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
  }
}