// Initialize for RGB->YCC colorspace conversion.
static void rgb_ycc_start(jpeg_compress cinfo)
{
my_color_converter cconvert = (my_color_converter)cinfo.cconvert;
int[] rgb_ycc_tab = null;
try
{
// Allocate and fill in the conversion tables.
cconvert.rgb_ycc_tab = rgb_ycc_tab = new int[TABLE_SIZE];
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
for (int i = 0; i <= MAXJSAMPLE; i++)
{
rgb_ycc_tab[i + R_Y_OFF] = FIX_029900 * i;
rgb_ycc_tab[i + G_Y_OFF] = FIX_058700 * i;
rgb_ycc_tab[i + B_Y_OFF] = FIX_011400 * i + ONE_HALF;
rgb_ycc_tab[i + R_CB_OFF] = (-FIX_016874) * i;
rgb_ycc_tab[i + G_CB_OFF] = (-FIX_033126) * 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] = FIX_050000 * i + CBCR_OFFSET + ONE_HALF - 1;
// B=>Cb and R=>Cr tables are the same
// rgb_ycc_tab[i+R_CR_OFF]=FIX_050000*i+CBCR_OFFSET+ONE_HALF-1;
rgb_ycc_tab[i + G_CR_OFF] = (-FIX_041869) * i;
rgb_ycc_tab[i + B_CR_OFF] = (-FIX_008131) * i;
}
}
// Convert some rows of samples to the JPEG colorspace.
// This version handles Adobe-style CMYK->YCCK conversion,
// where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
// conversion as above, while passing K (black) unchanged.
// We assume rgb_ycc_start has been called.
static void cmyk_ycck_convert(jpeg_compress cinfo, byte[][] input_buf, uint in_row_index, byte[][][] output_buf, uint output_row, int num_rows)
{
my_color_converter cconvert = (my_color_converter)cinfo.cconvert;
int r, g, b;
int[] ctab = cconvert.rgb_ycc_tab;
uint num_cols = cinfo.image_width;
for (uint input_row = 0; input_row < num_rows; input_row++)
{
byte[] inptr = input_buf[in_row_index + input_row];
byte[] outptr0 = output_buf[0][output_row];
byte[] outptr1 = output_buf[1][output_row];
byte[] outptr2 = output_buf[2][output_row];
byte[] outptr3 = output_buf[3][output_row];
output_row++;
for (uint col = 0, off = 0; col < num_cols; col++, off += 4)
{
r = MAXJSAMPLE - inptr[off + 0];
g = MAXJSAMPLE - inptr[off + 1];
b = MAXJSAMPLE - inptr[off + 2];
// K passes through as-is
outptr3[col] = inptr[off + 3];
// If the inputs are 0..MAXJSAMPLE, the outputs of these equations
// must be too; we do not need an explicit range-limiting operation.
outptr0[col] = (byte)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] + ctab[b + B_Y_OFF]) >> SCALEBITS); // Y
outptr1[col] = (byte)((ctab[r + R_CB_OFF] + ctab[g + G_CB_OFF] + ctab[b + B_CB_OFF]) >> SCALEBITS); // Cb
outptr2[col] = (byte)((ctab[r + R_CR_OFF] + ctab[g + G_CR_OFF] + ctab[b + B_CR_OFF]) >> SCALEBITS); // Cr
}
}
}
// Convert some rows of samples to the JPEG colorspace.
//
// Note that we change from the application's interleaved-pixel format
// to our internal noninterleaved, one-plane-per-component format.
// The input buffer is therefore three times as wide as the output buffer.
//
// A starting row offset is provided only for the output buffer. The caller
// can easily adjust the passed input_buf value to accommodate any row
// offset required on that side.
static void rgb_ycc_convert(jpeg_compress cinfo, byte[][] input_buf, uint in_row_index, byte[][][] output_buf, uint output_row, int num_rows)
{
my_color_converter cconvert = (my_color_converter)cinfo.cconvert;
int r, g, b;
int[] ctab = cconvert.rgb_ycc_tab;
uint num_cols = cinfo.image_width;
for (uint input_row = 0; input_row < num_rows; input_row++)
{
byte[] inptr = input_buf[in_row_index + input_row];
byte[] outptr0 = output_buf[0][output_row];
byte[] outptr1 = output_buf[1][output_row];
byte[] outptr2 = output_buf[2][output_row];
output_row++;
for (uint col = 0, off = 0; col < num_cols; col++, off += RGB_PIXELSIZE)
{
r = inptr[off + RGB_RED];
g = inptr[off + RGB_GREEN];
b = inptr[off + RGB_BLUE];
// If the inputs are 0..MAXJSAMPLE, the outputs of these equations
// must be too; we do not need an explicit range-limiting operation.
outptr0[col] = (byte)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] + ctab[b + B_Y_OFF]) >> SCALEBITS); // Y
outptr1[col] = (byte)((ctab[r + R_CB_OFF] + ctab[g + G_CB_OFF] + ctab[b + B_CB_OFF]) >> SCALEBITS); // Cb
outptr2[col] = (byte)((ctab[r + R_CR_OFF] + ctab[g + G_CR_OFF] + ctab[b + B_CR_OFF]) >> SCALEBITS); // Cr
//outptr0[col]=(byte)(0.299*r+0.587*g+0.114*b);
//outptr1[col]=(byte)(-0.168736*r-0.331264*g+0.5*b+CENTERJSAMPLE);
//outptr2[col]=(byte)(0.5*r-0.418688*g-0.081312*b+CENTERJSAMPLE);
}
}
}
// *************** Cases other than RGB -> YCbCr *************
// Convert some rows of samples to the JPEG colorspace.
// This version handles RGB->grayscale conversion, which is the same
// as the RGB->Y portion of RGB->YCbCr.
// We assume rgb_ycc_start has been called (we only use the Y tables).
static void rgb_gray_convert(jpeg_compress cinfo, byte[][] input_buf, uint in_row_index, byte[][][] output_buf, uint output_row, int num_rows)
{
my_color_converter cconvert = (my_color_converter)cinfo.cconvert;
int r, g, b;
int[] ctab = cconvert.rgb_ycc_tab;
uint num_cols = cinfo.image_width;
for (uint input_row = 0; input_row < num_rows; input_row++)
{
byte[] inptr = input_buf[in_row_index + input_row];
byte[] outptr = output_buf[0][output_row];
output_row++;
for (uint col = 0, off = 0; col < num_cols; col++, off += RGB_PIXELSIZE)
{
r = inptr[off + RGB_RED];
g = inptr[off + RGB_GREEN];
b = inptr[off + RGB_BLUE];
outptr[col] = (byte)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] + ctab[b + B_Y_OFF]) >> SCALEBITS); // Y
}
}
}
// Module initialization routine for input colorspace conversion.
static void jinit_color_converter(jpeg_compress cinfo)
{
my_color_converter cconvert = null;
try
{
cinfo.cconvert = cconvert = new my_color_converter();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
// set start_pass to null method until we find out differently
cconvert.start_pass = null_method;
// Make sure input_components agrees with in_color_space
switch (cinfo.in_color_space)
{
case J_COLOR_SPACE.JCS_GRAYSCALE:
if (cinfo.input_components != 1)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
}
break;
case J_COLOR_SPACE.JCS_RGB:
case J_COLOR_SPACE.JCS_YCbCr:
if (cinfo.input_components != 3)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
}
break;
case J_COLOR_SPACE.JCS_CMYK:
case J_COLOR_SPACE.JCS_YCCK:
if (cinfo.input_components != 4)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
}
break;
default: // JCS_UNKNOWN can be anything
if (cinfo.input_components < 1)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
}
break;
}
// Check num_components, set conversion method based on requested space
switch (cinfo.jpeg_color_space)
{
case J_COLOR_SPACE.JCS_GRAYSCALE:
if (cinfo.num_components != 1)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
}
if (cinfo.in_color_space == J_COLOR_SPACE.JCS_GRAYSCALE)
{
cconvert.color_convert = grayscale_convert;
}
else if (cinfo.in_color_space == J_COLOR_SPACE.JCS_RGB)
{
cconvert.start_pass = rgb_ycc_start;
cconvert.color_convert = rgb_gray_convert;
}
else if (cinfo.in_color_space == J_COLOR_SPACE.JCS_YCbCr)
{
cconvert.color_convert = grayscale_convert;
}
else
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
}
break;
case J_COLOR_SPACE.JCS_RGB:
if (cinfo.num_components != 3)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
}
if (cinfo.in_color_space == J_COLOR_SPACE.JCS_RGB && RGB_PIXELSIZE == 3)
{
cconvert.color_convert = null_convert;
}
else
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
}
break;
case J_COLOR_SPACE.JCS_YCbCr:
if (cinfo.num_components != 3)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
}
if (cinfo.in_color_space == J_COLOR_SPACE.JCS_RGB)
{
cconvert.start_pass = rgb_ycc_start;
cconvert.color_convert = rgb_ycc_convert;
}
else if (cinfo.in_color_space == J_COLOR_SPACE.JCS_YCbCr)
{
cconvert.color_convert = null_convert;
}
else
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
}
break;
case J_COLOR_SPACE.JCS_CMYK:
if (cinfo.num_components != 4)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
}
if (cinfo.in_color_space == J_COLOR_SPACE.JCS_CMYK)
{
cconvert.color_convert = null_convert;
}
else
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
}
break;
case J_COLOR_SPACE.JCS_YCCK:
if (cinfo.num_components != 4)
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
}
if (cinfo.in_color_space == J_COLOR_SPACE.JCS_CMYK)
{
cconvert.start_pass = rgb_ycc_start;
cconvert.color_convert = cmyk_ycck_convert;
}
else if (cinfo.in_color_space == J_COLOR_SPACE.JCS_YCCK)
{
cconvert.color_convert = null_convert;
}
else
{
ERREXIT(cinfo, J_MESSAGE_CODE.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, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
}
cconvert.color_convert = null_convert;
break;
}
}
// Module initialization routine for input colorspace conversion.
static void jinit_color_converter(jpeg_compress cinfo)
{
my_color_converter cconvert=null;
try
{
cinfo.cconvert=cconvert=new my_color_converter();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
// set start_pass to null method until we find out differently
cconvert.start_pass=null_method;
// Make sure input_components agrees with in_color_space
switch(cinfo.in_color_space)
{
case J_COLOR_SPACE.JCS_GRAYSCALE:
if(cinfo.input_components!=1) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
break;
case J_COLOR_SPACE.JCS_RGB:
case J_COLOR_SPACE.JCS_YCbCr:
if(cinfo.input_components!=3) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
break;
case J_COLOR_SPACE.JCS_CMYK:
case J_COLOR_SPACE.JCS_YCCK:
if(cinfo.input_components!=4) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
break;
default: // JCS_UNKNOWN can be anything
if(cinfo.input_components<1) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_IN_COLORSPACE);
break;
}
// Check num_components, set conversion method based on requested space
switch(cinfo.jpeg_color_space)
{
case J_COLOR_SPACE.JCS_GRAYSCALE:
if(cinfo.num_components!=1) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
if(cinfo.in_color_space==J_COLOR_SPACE.JCS_GRAYSCALE) cconvert.color_convert=grayscale_convert;
else if(cinfo.in_color_space==J_COLOR_SPACE.JCS_RGB)
{
cconvert.start_pass=rgb_ycc_start;
cconvert.color_convert=rgb_gray_convert;
}
else if(cinfo.in_color_space==J_COLOR_SPACE.JCS_YCbCr) cconvert.color_convert=grayscale_convert;
else ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
break;
case J_COLOR_SPACE.JCS_RGB:
if(cinfo.num_components!=3) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
if(cinfo.in_color_space==J_COLOR_SPACE.JCS_RGB&&RGB_PIXELSIZE==3) cconvert.color_convert=null_convert;
else ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
break;
case J_COLOR_SPACE.JCS_YCbCr:
if(cinfo.num_components!=3) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
if(cinfo.in_color_space==J_COLOR_SPACE.JCS_RGB)
{
cconvert.start_pass=rgb_ycc_start;
cconvert.color_convert=rgb_ycc_convert;
}
else if(cinfo.in_color_space==J_COLOR_SPACE.JCS_YCbCr) cconvert.color_convert=null_convert;
else ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
break;
case J_COLOR_SPACE.JCS_CMYK:
if(cinfo.num_components!=4) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
if(cinfo.in_color_space==J_COLOR_SPACE.JCS_CMYK) cconvert.color_convert=null_convert;
else ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
break;
case J_COLOR_SPACE.JCS_YCCK:
if(cinfo.num_components!=4)
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_J_COLORSPACE);
if(cinfo.in_color_space==J_COLOR_SPACE.JCS_CMYK)
{
cconvert.start_pass=rgb_ycc_start;
cconvert.color_convert=cmyk_ycck_convert;
}
else if(cinfo.in_color_space==J_COLOR_SPACE.JCS_YCCK) cconvert.color_convert=null_convert;
else ERREXIT(cinfo, J_MESSAGE_CODE.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, J_MESSAGE_CODE.JERR_CONVERSION_NOTIMPL);
cconvert.color_convert=null_convert;
break;
}
}
