jdpostct.cpp File Reference

#include "jinclude.h"
#include "jpeglib.h"

Include dependency graph for jdpostct.cpp:

Classes
struct	my_post_controller

Macros
#define	JPEG_INTERNALS

Typedefs
typedef my_post_controller *	my_post_ptr

Functions
static void	post_process_1pass (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail)
static void	post_process_prepass (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail)
static void	post_process_2pass (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail)
static void	start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
void	jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer)

Macro Definition Documentation

#define JPEG_INTERNALS

Typedef Documentation

typedef my_post_controller* my_post_ptr

Function Documentation

static void post_process_1pass ( j_decompress_ptr  cinfo, JSAMPIMAGE  input_buf, JDIMENSION *  in_row_group_ctr, JDIMENSION  in_row_groups_avail, JSAMPARRAY  output_buf, JDIMENSION *  out_row_ctr, JDIMENSION  out_rows_avail  )

static

{
  my_post_ptr post = (my_post_ptr) cinfo->post;
  JDIMENSION num_rows, max_rows;

  /* Fill the buffer, but not more than what we can dump out in one go. */
  /* Note we rely on the upsampler to detect bottom of image. */
  max_rows = out_rows_avail - *out_row_ctr;
  if (max_rows > post->strip_height)
    max_rows = post->strip_height;
  num_rows = 0;
  (*cinfo->upsample->upsample) (cinfo,
        input_buf, in_row_group_ctr, in_row_groups_avail,
        post->buffer, &num_rows, max_rows);
  /* Quantize and emit data. */
  (*cinfo->cquantize->color_quantize) (cinfo,
        post->buffer, output_buf + *out_row_ctr, (int) num_rows);
  *out_row_ctr += num_rows;
}

static void post_process_prepass ( j_decompress_ptr  cinfo, JSAMPIMAGE  input_buf, JDIMENSION *  in_row_group_ctr, JDIMENSION  in_row_groups_avail, JSAMPARRAY  output_buf, JDIMENSION *  out_row_ctr, JDIMENSION  out_rows_avail  )

static

{
  my_post_ptr post = (my_post_ptr) cinfo->post;
  JDIMENSION old_next_row, num_rows;

  /* Reposition virtual buffer if at start of strip. */
  if (post->next_row == 0) {
    post->buffer = (*cinfo->mem->access_virt_sarray)
    ((j_common_ptr) cinfo, post->whole_image,
     post->starting_row, post->strip_height, TRUE);
  }

  /* Upsample some data (up to a strip height's worth). */
  old_next_row = post->next_row;
  (*cinfo->upsample->upsample) (cinfo,
        input_buf, in_row_group_ctr, in_row_groups_avail,
        post->buffer, &post->next_row, post->strip_height);

  /* Allow quantizer to scan new data.  No data is emitted, */
  /* but we advance out_row_ctr so outer loop can tell when we're done. */
  if (post->next_row > old_next_row) {
    num_rows = post->next_row - old_next_row;
    (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
                     (JSAMPARRAY) NULL, (int) num_rows);
    *out_row_ctr += num_rows;
  }

  /* Advance if we filled the strip. */
  if (post->next_row >= post->strip_height) {
    post->starting_row += post->strip_height;
    post->next_row = 0;
  }
}

static void post_process_2pass ( j_decompress_ptr  cinfo, JSAMPIMAGE  input_buf, JDIMENSION *  in_row_group_ctr, JDIMENSION  in_row_groups_avail, JSAMPARRAY  output_buf, JDIMENSION *  out_row_ctr, JDIMENSION  out_rows_avail  )

static

{
  my_post_ptr post = (my_post_ptr) cinfo->post;
  JDIMENSION num_rows, max_rows;

  /* Reposition virtual buffer if at start of strip. */
  if (post->next_row == 0) {
    post->buffer = (*cinfo->mem->access_virt_sarray)
    ((j_common_ptr) cinfo, post->whole_image,
     post->starting_row, post->strip_height, FALSE);
  }

  /* Determine number of rows to emit. */
  num_rows = post->strip_height - post->next_row; /* available in strip */
  max_rows = out_rows_avail - *out_row_ctr; /* available in output area */
  if (num_rows > max_rows)
    num_rows = max_rows;
  /* We have to check bottom of image here, can't depend on upsampler. */
  max_rows = cinfo->output_height - post->starting_row;
  if (num_rows > max_rows)
    num_rows = max_rows;

  /* Quantize and emit data. */
  (*cinfo->cquantize->color_quantize) (cinfo,
        post->buffer + post->next_row, output_buf + *out_row_ctr,
        (int) num_rows);
  *out_row_ctr += num_rows;

  /* Advance if we filled the strip. */
  post->next_row += num_rows;
  if (post->next_row >= post->strip_height) {
    post->starting_row += post->strip_height;
    post->next_row = 0;
  }
}

static void start_pass_dpost ( j_decompress_ptr  cinfo, J_BUF_MODE  pass_mode  )

static

{
  my_post_ptr post = (my_post_ptr) cinfo->post;

  switch (pass_mode) {
  case JBUF_PASS_THRU:
    if (cinfo->quantize_colors) {
      /* Single-pass processing with color quantization. */
      post->pub.post_process_data = post_process_1pass;
      /* We could be doing buffered-image output before starting a 2-pass
       * color quantization; in that case, jinit_d_post_controller did not
       * allocate a strip buffer.  Use the virtual-array buffer as workspace.
       */
      if (post->buffer == NULL) {
    post->buffer = (*cinfo->mem->access_virt_sarray)
      ((j_common_ptr) cinfo, post->whole_image,
       (JDIMENSION) 0, post->strip_height, TRUE);
      }
    } else {
      /* For single-pass processing without color quantization,
       * I have no work to do; just call the upsampler directly.
       */
      post->pub.post_process_data = cinfo->upsample->upsample;
    }
    break;
#ifdef QUANT_2PASS_SUPPORTED
  case JBUF_SAVE_AND_PASS:
    /* First pass of 2-pass quantization */
    if (post->whole_image == NULL)
      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    post->pub.post_process_data = post_process_prepass;
    break;
  case JBUF_CRANK_DEST:
    /* Second pass of 2-pass quantization */
    if (post->whole_image == NULL)
      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    post->pub.post_process_data = post_process_2pass;
    break;
#endif /* QUANT_2PASS_SUPPORTED */
  default:
    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    break;
  }
  post->starting_row = post->next_row = 0;
}

void jinit_d_post_controller	(	j_decompress_ptr	cinfo,
		boolean	need_full_buffer
	)

{
  my_post_ptr post;

  post = (my_post_ptr)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                SIZEOF(my_post_controller));
  cinfo->post = (struct jpeg_d_post_controller *) post;
  post->pub.start_pass = start_pass_dpost;
  post->whole_image = NULL; /* flag for no virtual arrays */
  post->buffer = NULL;      /* flag for no strip buffer */

  /* Create the quantization buffer, if needed */
  if (cinfo->quantize_colors) {
    /* The buffer strip height is max_v_samp_factor, which is typically
     * an efficient number of rows for upsampling to return.
     * (In the presence of output rescaling, we might want to be smarter?)
     */
    post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
    if (need_full_buffer) {
      /* Two-pass color quantization: need full-image storage. */
      /* We round up the number of rows to a multiple of the strip height. */
#ifdef QUANT_2PASS_SUPPORTED
      post->whole_image = (*cinfo->mem->request_virt_sarray)
    ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
     cinfo->output_width * cinfo->out_color_components,
     (JDIMENSION) jround_up((long) cinfo->output_height,
                (long) post->strip_height),
     post->strip_height);
#else
      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
#endif /* QUANT_2PASS_SUPPORTED */
    } else {
      /* One-pass color quantization: just make a strip buffer. */
      post->buffer = (*cinfo->mem->alloc_sarray)
    ((j_common_ptr) cinfo, JPOOL_IMAGE,
     cinfo->output_width * cinfo->out_color_components,
     post->strip_height);
    }
  }
}