jccolor.c File Reference

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

Include dependency graph for jccolor.c:

Go to the source code of this file.

Classes
struct	my_color_converter

Macros
#define	JPEG_INTERNALS
#define	SCALEBITS   16 /* speediest right-shift on some machines */
#define	CBCR_OFFSET   ((INT32) CENTERJSAMPLE << SCALEBITS)
#define	ONE_HALF   ((INT32) 1 << (SCALEBITS-1))
#define	FIX(x)   ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
#define	R_Y_OFF   0 /* offset to R => Y section */
#define	G_Y_OFF   (1*(MAXJSAMPLE+1)) /* offset to G => Y section */
#define	B_Y_OFF   (2*(MAXJSAMPLE+1)) /* etc. */
#define	R_CB_OFF   (3*(MAXJSAMPLE+1))
#define	G_CB_OFF   (4*(MAXJSAMPLE+1))
#define	B_CB_OFF   (5*(MAXJSAMPLE+1))
#define	R_CR_OFF   B_CB_OFF /* B=>Cb, R=>Cr are the same */
#define	G_CR_OFF   (6*(MAXJSAMPLE+1))
#define	B_CR_OFF   (7*(MAXJSAMPLE+1))
#define	TABLE_SIZE   (8*(MAXJSAMPLE+1))

Typedefs
typedef my_color_converter *	my_cconvert_ptr

Functions
	rgb_ycc_start (j_compress_ptr cinfo)
	rgb_ycc_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	rgb_gray_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	cmyk_ycck_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	rgb_rgb1_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	grayscale_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	rgb_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	null_convert (j_compress_ptr cinfo, JSAMPARRAY input_buf, JSAMPIMAGE output_buf, JDIMENSION output_row, int num_rows)
	null_method (j_compress_ptr cinfo)
	jinit_color_converter (j_compress_ptr cinfo)

Macro Definition Documentation

B_CB_OFF

#define B_CB_OFF   (5*(MAXJSAMPLE+1))

Definition at line 87 of file jccolor.c.

B_CR_OFF

#define B_CR_OFF   (7*(MAXJSAMPLE+1))

Definition at line 90 of file jccolor.c.

B_Y_OFF

#define B_Y_OFF   (2*(MAXJSAMPLE+1)) /* etc. */

Definition at line 84 of file jccolor.c.

CBCR_OFFSET

#define CBCR_OFFSET   ((INT32) CENTERJSAMPLE << SCALEBITS)

Definition at line 72 of file jccolor.c.

FIX

#define FIX

(

x

)

((INT32) ((x) * (1L<<SCALEBITS) + 0.5))

Definition at line 74 of file jccolor.c.

G_CB_OFF

#define G_CB_OFF   (4*(MAXJSAMPLE+1))

Definition at line 86 of file jccolor.c.

G_CR_OFF

#define G_CR_OFF   (6*(MAXJSAMPLE+1))

Definition at line 89 of file jccolor.c.

G_Y_OFF

#define G_Y_OFF   (1*(MAXJSAMPLE+1)) /* offset to G => Y section */

Definition at line 83 of file jccolor.c.

JPEG_INTERNALS

#define JPEG_INTERNALS

Definition at line 12 of file jccolor.c.

ONE_HALF

#define ONE_HALF   ((INT32) 1 << (SCALEBITS-1))

Definition at line 73 of file jccolor.c.

R_CB_OFF

#define R_CB_OFF   (3*(MAXJSAMPLE+1))

Definition at line 85 of file jccolor.c.

R_CR_OFF

#define R_CR_OFF   B_CB_OFF /* B=>Cb, R=>Cr are the same */

Definition at line 88 of file jccolor.c.

R_Y_OFF

#define R_Y_OFF   0 /* offset to R => Y section */

Definition at line 82 of file jccolor.c.

SCALEBITS

#define SCALEBITS   16 /* speediest right-shift on some machines */

Definition at line 71 of file jccolor.c.

TABLE_SIZE

#define TABLE_SIZE   (8*(MAXJSAMPLE+1))

Definition at line 91 of file jccolor.c.

Typedef Documentation

my_cconvert_ptr

typedef my_color_converter* my_cconvert_ptr

Definition at line 26 of file jccolor.c.

Function Documentation

cmyk_ycck_convert()

cmyk_ycck_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 234 of file jccolor.c.

{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register int r, g, b;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2, outptr3;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    outptr3 = output_buf[3][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
      g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
      b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
      /* K passes through as-is */
      outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
      inptr += 4;
      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
       * must be too; we do not need an explicit range-limiting operation.
       * Hence the value being shifted is never negative, and we don't
       * need the general RIGHT_SHIFT macro.
       */
      /* Y */
      outptr0[col] = (JSAMPLE)
        ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
         >> SCALEBITS);
      /* Cb */
      outptr1[col] = (JSAMPLE)
        ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
         >> SCALEBITS);
      /* Cr */
      outptr2[col] = (JSAMPLE)
        ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
         >> SCALEBITS);
    }
  }
}

Referenced by jinit_color_converter().

grayscale_convert()

grayscale_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 331 of file jccolor.c.

{
  register JSAMPROW inptr;
  register JSAMPROW outptr;
  register JDIMENSION count;
  register int instride = cinfo->input_components;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr = output_buf[0][output_row++];
    for (count = num_cols; count > 0; count--) {
      *outptr++ = *inptr;   /* don't need GETJSAMPLE() here */
      inptr += instride;
    }
  }
}

Referenced by jinit_color_converter().

jinit_color_converter()

jinit_color_converter

(

j_compress_ptr

cinfo

)

Definition at line 435 of file jccolor.c.

{
  my_cconvert_ptr cconvert;
 
  cconvert = (my_cconvert_ptr) (*cinfo->mem->alloc_small)
    ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_color_converter));
  cinfo->cconvert = &cconvert->pub;
  /* set start_pass to null method until we find out differently */
  cconvert->pub.start_pass = null_method;
 
  /* Make sure input_components agrees with in_color_space */
  switch (cinfo->in_color_space) {
  case JCS_GRAYSCALE:
    if (cinfo->input_components != 1)
      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
    break;
 
  case JCS_RGB:
  case JCS_BG_RGB:
#if RGB_PIXELSIZE != 3
    if (cinfo->input_components != RGB_PIXELSIZE)
      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
    break;
#endif /* else share code with YCbCr */
 
  case JCS_YCbCr:
  case JCS_BG_YCC:
    if (cinfo->input_components != 3)
      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
    break;
 
  case JCS_CMYK:
  case JCS_YCCK:
    if (cinfo->input_components != 4)
      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
    break;
 
  default:          /* JCS_UNKNOWN can be anything */
    if (cinfo->input_components < 1)
      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
  }
 
  /* Support color transform only for RGB colorspaces */
  if (cinfo->color_transform &&
      (cinfo->LSE_maxtrans != MAXJSAMPLE ||
       (cinfo->jpeg_color_space != JCS_RGB &&
    cinfo->jpeg_color_space != JCS_BG_RGB)))
    ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
 
  /* Check num_components, set conversion method based on requested space */
  switch (cinfo->jpeg_color_space) {
  case JCS_GRAYSCALE:
    if (cinfo->num_components != 1)
      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
    switch (cinfo->in_color_space) {
    case JCS_GRAYSCALE:
    case JCS_YCbCr:
    case JCS_BG_YCC:
      cconvert->pub.color_convert = grayscale_convert;
      break;
    case JCS_RGB:
      cconvert->pub.start_pass = rgb_ycc_start;
      cconvert->pub.color_convert = rgb_gray_convert;
      break;
    default:
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    }
    break;
 
  case JCS_RGB:
  case JCS_BG_RGB:
    if (cinfo->num_components != 3)
      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
    if (cinfo->in_color_space != cinfo->jpeg_color_space)
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    switch (cinfo->color_transform) {
    case JCT_NONE:
      cconvert->pub.color_convert = rgb_convert;
      break;
    case JCT_SUBTRACT_GREEN:
      cconvert->pub.color_convert = rgb_rgb1_convert;
      break;
    default:
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    }
    break;
 
  case JCS_YCbCr:
    if (cinfo->num_components != 3)
      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
    switch (cinfo->in_color_space) {
    case JCS_RGB:
      cconvert->pub.start_pass = rgb_ycc_start;
      cconvert->pub.color_convert = rgb_ycc_convert;
      break;
    case JCS_YCbCr:
      cconvert->pub.color_convert = null_convert;
      break;
    default:
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    }
    break;
 
  case JCS_BG_YCC:
    if (cinfo->num_components != 3)
      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
    switch (cinfo->in_color_space) {
    case JCS_RGB:
      /* For conversion from normal RGB input to BG_YCC representation,
       * the Cb/Cr values are first computed as usual, and then
       * quantized further after DCT processing by a factor of
       * 2 in reference to the nominal quantization factor.
       */
      /* need quantization scale by factor of 2 after DCT */
      cinfo->comp_info[1].component_needed = TRUE;
      cinfo->comp_info[2].component_needed = TRUE;
      /* compute normal YCC first */
      cconvert->pub.start_pass = rgb_ycc_start;
      cconvert->pub.color_convert = rgb_ycc_convert;
      break;
    case JCS_YCbCr:
      /* need quantization scale by factor of 2 after DCT */
      cinfo->comp_info[1].component_needed = TRUE;
      cinfo->comp_info[2].component_needed = TRUE;
      /*FALLTHROUGH*/
    case JCS_BG_YCC:
      /* Pass through for BG_YCC input */
      cconvert->pub.color_convert = null_convert;
      break;
    default:
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    }
    break;
 
  case JCS_CMYK:
    if (cinfo->num_components != 4)
      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
    if (cinfo->in_color_space != JCS_CMYK)
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    cconvert->pub.color_convert = null_convert;
    break;
 
  case JCS_YCCK:
    if (cinfo->num_components != 4)
      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
    switch (cinfo->in_color_space) {
    case JCS_CMYK:
      cconvert->pub.start_pass = rgb_ycc_start;
      cconvert->pub.color_convert = cmyk_ycck_convert;
      break;
    case JCS_YCCK:
      cconvert->pub.color_convert = null_convert;
      break;
    default:
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    }
    break;
 
  default:          /* allow null conversion of JCS_UNKNOWN */
    if (cinfo->jpeg_color_space != cinfo->in_color_space ||
    cinfo->num_components != cinfo->input_components)
      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
    cconvert->pub.color_convert = null_convert;
  }
}

Referenced by jinit_compress_master().

null_convert()

null_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 392 of file jccolor.c.

{
  register JSAMPROW inptr;
  register JSAMPROW outptr;
  register JDIMENSION count;
  register int num_comps = cinfo->num_components;
  JDIMENSION num_cols = cinfo->image_width;
  int ci;
 
  while (--num_rows >= 0) {
    /* It seems fastest to make a separate pass for each component. */
    for (ci = 0; ci < num_comps; ci++) {
      inptr = input_buf[0] + ci;
      outptr = output_buf[ci][output_row];
      for (count = num_cols; count > 0; count--) {
    *outptr++ = *inptr; /* don't need GETJSAMPLE() here */
    inptr += num_comps;
      }
    }
    input_buf++;
    output_row++;
  }
}

Referenced by jinit_color_converter().

null_method()

null_method

(

j_compress_ptr

cinfo

)

Definition at line 424 of file jccolor.c.

{
  /* no work needed */
}

Referenced by jinit_color_converter().

rgb_convert()

rgb_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 359 of file jccolor.c.

{
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      /* We can dispense with GETJSAMPLE() here */
      outptr0[col] = inptr[RGB_RED];
      outptr1[col] = inptr[RGB_GREEN];
      outptr2[col] = inptr[RGB_BLUE];
      inptr += RGB_PIXELSIZE;
    }
  }
}

Referenced by jinit_color_converter().

rgb_gray_convert()

rgb_gray_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 199 of file jccolor.c.

{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register INT32 y;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr = output_buf[0][output_row++];
    for (col = 0; col < num_cols; col++) {
      y  = ctab[R_Y_OFF + GETJSAMPLE(inptr[RGB_RED])];
      y += ctab[G_Y_OFF + GETJSAMPLE(inptr[RGB_GREEN])];
      y += ctab[B_Y_OFF + GETJSAMPLE(inptr[RGB_BLUE])];
      inptr += RGB_PIXELSIZE;
      outptr[col] = (JSAMPLE) (y >> SCALEBITS);
    }
  }
}

Referenced by jinit_color_converter().

rgb_rgb1_convert()

rgb_rgb1_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 292 of file jccolor.c.

{
  register int r, g, b;
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = GETJSAMPLE(inptr[RGB_RED]);
      g = GETJSAMPLE(inptr[RGB_GREEN]);
      b = GETJSAMPLE(inptr[RGB_BLUE]);
      inptr += RGB_PIXELSIZE;
      /* Assume that MAXJSAMPLE+1 is a power of 2, so that the MOD
       * (modulo) operator is equivalent to the bitmask operator AND.
       */
      outptr0[col] = (JSAMPLE) ((r - g + CENTERJSAMPLE) & MAXJSAMPLE);
      outptr1[col] = (JSAMPLE) g;
      outptr2[col] = (JSAMPLE) ((b - g + CENTERJSAMPLE) & MAXJSAMPLE);
    }
  }
}

Referenced by jinit_color_converter().

rgb_ycc_convert()

rgb_ycc_convert	(	j_compress_ptr	cinfo,
		JSAMPARRAY	input_buf,
		JSAMPIMAGE	output_buf,
		JDIMENSION	output_row,
		int	num_rows
	)

Definition at line 143 of file jccolor.c.

{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register int r, g, b;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = GETJSAMPLE(inptr[RGB_RED]);
      g = GETJSAMPLE(inptr[RGB_GREEN]);
      b = GETJSAMPLE(inptr[RGB_BLUE]);
      inptr += RGB_PIXELSIZE;
      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
       * must be too; we do not need an explicit range-limiting operation.
       * Hence the value being shifted is never negative, and we don't
       * need the general RIGHT_SHIFT macro.
       */
      /* Y */
      outptr0[col] = (JSAMPLE)
        ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
         >> SCALEBITS);
      /* Cb */
      outptr1[col] = (JSAMPLE)
        ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
         >> SCALEBITS);
      /* Cr */
      outptr2[col] = (JSAMPLE)
        ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
         >> SCALEBITS);
    }
  }
}

Referenced by jinit_color_converter().

rgb_ycc_start()

rgb_ycc_start

(

j_compress_ptr

cinfo

)

Definition at line 99 of file jccolor.c.

{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  INT32 * rgb_ycc_tab;
  INT32 i;
 
  /* Allocate and fill in the conversion tables. */
  cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                TABLE_SIZE * SIZEOF(INT32));
 
  for (i = 0; i <= MAXJSAMPLE; i++) {
    rgb_ycc_tab[i+R_Y_OFF] = FIX(0.299) * i;
    rgb_ycc_tab[i+G_Y_OFF] = FIX(0.587) * i;
    rgb_ycc_tab[i+B_Y_OFF] = FIX(0.114) * i + ONE_HALF;
    rgb_ycc_tab[i+R_CB_OFF] = (- FIX(0.168735892)) * i;
    rgb_ycc_tab[i+G_CB_OFF] = (- FIX(0.331264108)) * i;
    /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
     * This ensures that the maximum output will round to MAXJSAMPLE
     * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
     */
    rgb_ycc_tab[i+B_CB_OFF] = (i << (SCALEBITS-1)) + CBCR_OFFSET + ONE_HALF-1;
/*  B=>Cb and R=>Cr tables are the same
    rgb_ycc_tab[i+R_CR_OFF] = (i << (SCALEBITS-1)) + CBCR_OFFSET + ONE_HALF-1;
*/
    rgb_ycc_tab[i+G_CR_OFF] = (- FIX(0.418687589)) * i;
    rgb_ycc_tab[i+B_CR_OFF] = (- FIX(0.081312411)) * i;
  }
}

Referenced by jinit_color_converter().