view release on metacpan or  search on metacpan

src/Source/LibJPEG/jctrans.c  view on Meta::CPAN

   */
  if (srcinfo->saw_JFIF_marker) {
    if (srcinfo->JFIF_major_version == 1 ||
	srcinfo->JFIF_major_version == 2) {
      dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
      dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
    }
    dstinfo->density_unit = srcinfo->density_unit;
    dstinfo->X_density = srcinfo->X_density;
    dstinfo->Y_density = srcinfo->Y_density;
  }
}


/*
 * Master selection of compression modules for transcoding.
 * This substitutes for jcinit.c's initialization of the full compressor.
 */

LOCAL(void)
transencode_master_selection (j_compress_ptr cinfo,
			      jvirt_barray_ptr * coef_arrays)
{
  /* Initialize master control (includes parameter checking/processing) */
  jinit_c_master_control(cinfo, TRUE /* transcode only */);

  /* Entropy encoding: either Huffman or arithmetic coding. */
  if (cinfo->arith_code)
    jinit_arith_encoder(cinfo);
  else {
    jinit_huff_encoder(cinfo);
  }

  /* We need a special coefficient buffer controller. */
  transencode_coef_controller(cinfo, coef_arrays);

  jinit_marker_writer(cinfo);

  /* We can now tell the memory manager to allocate virtual arrays. */
  (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);

  /* Write the datastream header (SOI, JFIF) immediately.
   * Frame and scan headers are postponed till later.
   * This lets application insert special markers after the SOI.
   */
  (*cinfo->marker->write_file_header) (cinfo);
}


/*
 * The rest of this file is a special implementation of the coefficient
 * buffer controller.  This is similar to jccoefct.c, but it handles only
 * output from presupplied virtual arrays.  Furthermore, we generate any
 * dummy padding blocks on-the-fly rather than expecting them to be present
 * in the arrays.
 */

/* Private buffer controller object */

typedef struct {
  struct jpeg_c_coef_controller pub; /* public fields */

  JDIMENSION iMCU_row_num;	/* iMCU row # within image */
  JDIMENSION mcu_ctr;		/* counts MCUs processed in current row */
  int MCU_vert_offset;		/* counts MCU rows within iMCU row */
  int MCU_rows_per_iMCU_row;	/* number of such rows needed */

  /* Virtual block array for each component. */
  jvirt_barray_ptr * whole_image;

  /* Workspace for constructing dummy blocks at right/bottom edges. */
  JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
} my_coef_controller;

typedef my_coef_controller * my_coef_ptr;


LOCAL(void)
start_iMCU_row (j_compress_ptr cinfo)
/* Reset within-iMCU-row counters for a new row */
{
  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

  /* In an interleaved scan, an MCU row is the same as an iMCU row.
   * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
   * But at the bottom of the image, process only what's left.
   */
  if (cinfo->comps_in_scan > 1) {
    coef->MCU_rows_per_iMCU_row = 1;
  } else {
    if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
    else
      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
  }

  coef->mcu_ctr = 0;
  coef->MCU_vert_offset = 0;
}


/*
 * Initialize for a processing pass.
 */

METHODDEF(void)
start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
{
  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

  if (pass_mode != JBUF_CRANK_DEST)
    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

  coef->iMCU_row_num = 0;
  start_iMCU_row(cinfo);
}


/*
 * Process some data.
 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)