| /* |
| * jdcolor.c |
| * |
| * Copyright (C) 1991-1997, Thomas G. Lane. |
| * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB |
| * Copyright (C) 2009, D. R. Commander. |
| * This file is part of the Independent JPEG Group's software. |
| * For conditions of distribution and use, see the accompanying README file. |
| * |
| * This file contains output colorspace conversion routines. |
| */ |
| |
| #define JPEG_INTERNALS |
| #include "jinclude.h" |
| #include "jpeglib.h" |
| #include "jsimd.h" |
| |
| |
| /* Private subobject */ |
| |
| typedef struct { |
| struct jpeg_color_deconverter pub; /* public fields */ |
| |
| /* Private state for YCC->RGB conversion */ |
| int * Cr_r_tab; /* => table for Cr to R conversion */ |
| int * Cb_b_tab; /* => table for Cb to B conversion */ |
| INT32 * Cr_g_tab; /* => table for Cr to G conversion */ |
| INT32 * Cb_g_tab; /* => table for Cb to G conversion */ |
| } my_color_deconverter; |
| |
| typedef my_color_deconverter * my_cconvert_ptr; |
| |
| |
| /**************** YCbCr -> RGB conversion: most common case **************/ |
| |
| /* |
| * YCbCr is defined per CCIR 601-1, except that Cb and Cr are |
| * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5. |
| * The conversion equations to be implemented are therefore |
| * R = Y + 1.40200 * Cr |
| * G = Y - 0.34414 * Cb - 0.71414 * Cr |
| * B = Y + 1.77200 * Cb |
| * where Cb and Cr represent the incoming values less CENTERJSAMPLE. |
| * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.) |
| * |
| * To avoid floating-point arithmetic, we represent the fractional constants |
| * as integers scaled up by 2^16 (about 4 digits precision); we have to divide |
| * the products by 2^16, with appropriate rounding, to get the correct answer. |
| * Notice that Y, being an integral input, does not contribute any fraction |
| * so it need not participate in the rounding. |
| * |
| * For even more speed, we avoid doing any multiplications in the inner loop |
| * by precalculating the constants times Cb and Cr for all possible values. |
| * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table); |
| * for 12-bit samples it is still acceptable. It's not very reasonable for |
| * 16-bit samples, but if you want lossless storage you shouldn't be changing |
| * colorspace anyway. |
| * The Cr=>R and Cb=>B values can be rounded to integers in advance; the |
| * values for the G calculation are left scaled up, since we must add them |
| * together before rounding. |
| */ |
| |
| #define SCALEBITS 16 /* speediest right-shift on some machines */ |
| #define ONE_HALF ((INT32) 1 << (SCALEBITS-1)) |
| #define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5)) |
| |
| |
| /* |
| * Initialize tables for YCC->RGB colorspace conversion. |
| */ |
| |
| LOCAL(void) |
| build_ycc_rgb_table (j_decompress_ptr cinfo) |
| { |
| my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; |
| int i; |
| INT32 x; |
| SHIFT_TEMPS |
| |
| cconvert->Cr_r_tab = (int *) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| (MAXJSAMPLE+1) * SIZEOF(int)); |
| cconvert->Cb_b_tab = (int *) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| (MAXJSAMPLE+1) * SIZEOF(int)); |
| cconvert->Cr_g_tab = (INT32 *) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| (MAXJSAMPLE+1) * SIZEOF(INT32)); |
| cconvert->Cb_g_tab = (INT32 *) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| (MAXJSAMPLE+1) * SIZEOF(INT32)); |
| |
| for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) { |
| /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */ |
| /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */ |
| /* Cr=>R value is nearest int to 1.40200 * x */ |
| cconvert->Cr_r_tab[i] = (int) |
| RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS); |
| /* Cb=>B value is nearest int to 1.77200 * x */ |
| cconvert->Cb_b_tab[i] = (int) |
| RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS); |
| /* Cr=>G value is scaled-up -0.71414 * x */ |
| cconvert->Cr_g_tab[i] = (- FIX(0.71414)) * x; |
| /* Cb=>G value is scaled-up -0.34414 * x */ |
| /* We also add in ONE_HALF so that need not do it in inner loop */ |
| cconvert->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF; |
| } |
| } |
| |
| |
| /* |
| * Convert some rows of samples to the output colorspace. |
| * |
| * Note that we change from noninterleaved, one-plane-per-component format |
| * to interleaved-pixel format. The output buffer is therefore three times |
| * as wide as the input buffer. |
| * A starting row offset is provided only for the input buffer. The caller |
| * can easily adjust the passed output_buf value to accommodate any row |
| * offset required on that side. |
| */ |
| |
| METHODDEF(void) |
| ycc_rgb_convert (j_decompress_ptr cinfo, |
| JSAMPIMAGE input_buf, JDIMENSION input_row, |
| JSAMPARRAY output_buf, int num_rows) |
| { |
| my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; |
| register int y, cb, cr; |
| register JSAMPROW outptr; |
| register JSAMPROW inptr0, inptr1, inptr2; |
| register JDIMENSION col; |
| JDIMENSION num_cols = cinfo->output_width; |
| int rindex = rgb_red[cinfo->out_color_space]; |
| int gindex = rgb_green[cinfo->out_color_space]; |
| int bindex = rgb_blue[cinfo->out_color_space]; |
| int rgbstride = rgb_pixelsize[cinfo->out_color_space]; |
| /* copy these pointers into registers if possible */ |
| register JSAMPLE * range_limit = cinfo->sample_range_limit; |
| register int * Crrtab = cconvert->Cr_r_tab; |
| register int * Cbbtab = cconvert->Cb_b_tab; |
| register INT32 * Crgtab = cconvert->Cr_g_tab; |
| register INT32 * Cbgtab = cconvert->Cb_g_tab; |
| SHIFT_TEMPS |
| |
| while (--num_rows >= 0) { |
| inptr0 = input_buf[0][input_row]; |
| inptr1 = input_buf[1][input_row]; |
| inptr2 = input_buf[2][input_row]; |
| input_row++; |
| outptr = *output_buf++; |
| for (col = 0; col < num_cols; col++) { |
| y = GETJSAMPLE(inptr0[col]); |
| cb = GETJSAMPLE(inptr1[col]); |
| cr = GETJSAMPLE(inptr2[col]); |
| /* Range-limiting is essential due to noise introduced by DCT losses. */ |
| outptr[rindex] = range_limit[y + Crrtab[cr]]; |
| outptr[gindex] = range_limit[y + |
| ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], |
| SCALEBITS))]; |
| outptr[bindex] = range_limit[y + Cbbtab[cb]]; |
| outptr += rgbstride; |
| } |
| } |
| } |
| |
| |
| /**************** Cases other than YCbCr -> RGB **************/ |
| |
| |
| /* |
| * Color conversion for no colorspace change: just copy the data, |
| * converting from separate-planes to interleaved representation. |
| */ |
| |
| METHODDEF(void) |
| null_convert (j_decompress_ptr cinfo, |
| JSAMPIMAGE input_buf, JDIMENSION input_row, |
| JSAMPARRAY output_buf, int num_rows) |
| { |
| register JSAMPROW inptr, outptr; |
| register JDIMENSION count; |
| register int num_components = cinfo->num_components; |
| JDIMENSION num_cols = cinfo->output_width; |
| int ci; |
| |
| while (--num_rows >= 0) { |
| for (ci = 0; ci < num_components; ci++) { |
| inptr = input_buf[ci][input_row]; |
| outptr = output_buf[0] + ci; |
| for (count = num_cols; count > 0; count--) { |
| *outptr = *inptr++; /* needn't bother with GETJSAMPLE() here */ |
| outptr += num_components; |
| } |
| } |
| input_row++; |
| output_buf++; |
| } |
| } |
| |
| |
| /* |
| * Color conversion for grayscale: just copy the data. |
| * This also works for YCbCr -> grayscale conversion, in which |
| * we just copy the Y (luminance) component and ignore chrominance. |
| */ |
| |
| METHODDEF(void) |
| grayscale_convert (j_decompress_ptr cinfo, |
| JSAMPIMAGE input_buf, JDIMENSION input_row, |
| JSAMPARRAY output_buf, int num_rows) |
| { |
| jcopy_sample_rows(input_buf[0], (int) input_row, output_buf, 0, |
| num_rows, cinfo->output_width); |
| } |
| |
| |
| /* |
| * Convert grayscale to RGB: just duplicate the graylevel three times. |
| * This is provided to support applications that don't want to cope |
| * with grayscale as a separate case. |
| */ |
| |
| METHODDEF(void) |
| gray_rgb_convert (j_decompress_ptr cinfo, |
| JSAMPIMAGE input_buf, JDIMENSION input_row, |
| JSAMPARRAY output_buf, int num_rows) |
| { |
| register JSAMPROW inptr, outptr; |
| JSAMPLE *maxinptr; |
| JDIMENSION num_cols = cinfo->output_width; |
| int rindex = rgb_red[cinfo->out_color_space]; |
| int gindex = rgb_green[cinfo->out_color_space]; |
| int bindex = rgb_blue[cinfo->out_color_space]; |
| int rgbstride = rgb_pixelsize[cinfo->out_color_space]; |
| |
| while (--num_rows >= 0) { |
| inptr = input_buf[0][input_row++]; |
| maxinptr = &inptr[num_cols]; |
| outptr = *output_buf++; |
| for (; inptr < maxinptr; inptr++, outptr += rgbstride) { |
| /* We can dispense with GETJSAMPLE() here */ |
| outptr[rindex] = outptr[gindex] = outptr[bindex] = *inptr; |
| } |
| } |
| } |
| |
| |
| /* |
| * Adobe-style YCCK->CMYK conversion. |
| * We convert YCbCr to R=1-C, G=1-M, and B=1-Y using the same |
| * conversion as above, while passing K (black) unchanged. |
| * We assume build_ycc_rgb_table has been called. |
| */ |
| |
| METHODDEF(void) |
| ycck_cmyk_convert (j_decompress_ptr cinfo, |
| JSAMPIMAGE input_buf, JDIMENSION input_row, |
| JSAMPARRAY output_buf, int num_rows) |
| { |
| my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; |
| register int y, cb, cr; |
| register JSAMPROW outptr; |
| register JSAMPROW inptr0, inptr1, inptr2, inptr3; |
| register JDIMENSION col; |
| JDIMENSION num_cols = cinfo->output_width; |
| /* copy these pointers into registers if possible */ |
| register JSAMPLE * range_limit = cinfo->sample_range_limit; |
| register int * Crrtab = cconvert->Cr_r_tab; |
| register int * Cbbtab = cconvert->Cb_b_tab; |
| register INT32 * Crgtab = cconvert->Cr_g_tab; |
| register INT32 * Cbgtab = cconvert->Cb_g_tab; |
| SHIFT_TEMPS |
| |
| while (--num_rows >= 0) { |
| inptr0 = input_buf[0][input_row]; |
| inptr1 = input_buf[1][input_row]; |
| inptr2 = input_buf[2][input_row]; |
| inptr3 = input_buf[3][input_row]; |
| input_row++; |
| outptr = *output_buf++; |
| for (col = 0; col < num_cols; col++) { |
| y = GETJSAMPLE(inptr0[col]); |
| cb = GETJSAMPLE(inptr1[col]); |
| cr = GETJSAMPLE(inptr2[col]); |
| /* Range-limiting is essential due to noise introduced by DCT losses. */ |
| outptr[0] = range_limit[MAXJSAMPLE - (y + Crrtab[cr])]; /* red */ |
| outptr[1] = range_limit[MAXJSAMPLE - (y + /* green */ |
| ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], |
| SCALEBITS)))]; |
| outptr[2] = range_limit[MAXJSAMPLE - (y + Cbbtab[cb])]; /* blue */ |
| /* K passes through unchanged */ |
| outptr[3] = inptr3[col]; /* don't need GETJSAMPLE here */ |
| outptr += 4; |
| } |
| } |
| } |
| |
| |
| /* |
| * Empty method for start_pass. |
| */ |
| |
| METHODDEF(void) |
| start_pass_dcolor (j_decompress_ptr cinfo) |
| { |
| /* no work needed */ |
| } |
| |
| |
| /* |
| * Module initialization routine for output colorspace conversion. |
| */ |
| |
| GLOBAL(void) |
| jinit_color_deconverter (j_decompress_ptr cinfo) |
| { |
| my_cconvert_ptr cconvert; |
| int ci; |
| |
| cconvert = (my_cconvert_ptr) |
| (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| SIZEOF(my_color_deconverter)); |
| cinfo->cconvert = (struct jpeg_color_deconverter *) cconvert; |
| cconvert->pub.start_pass = start_pass_dcolor; |
| |
| /* Make sure num_components agrees with jpeg_color_space */ |
| switch (cinfo->jpeg_color_space) { |
| case JCS_GRAYSCALE: |
| if (cinfo->num_components != 1) |
| ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); |
| break; |
| |
| case JCS_RGB: |
| case JCS_YCbCr: |
| if (cinfo->num_components != 3) |
| ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); |
| break; |
| |
| case JCS_CMYK: |
| case JCS_YCCK: |
| if (cinfo->num_components != 4) |
| ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); |
| break; |
| |
| default: /* JCS_UNKNOWN can be anything */ |
| if (cinfo->num_components < 1) |
| ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); |
| break; |
| } |
| |
| /* Set out_color_components and conversion method based on requested space. |
| * Also clear the component_needed flags for any unused components, |
| * so that earlier pipeline stages can avoid useless computation. |
| */ |
| |
| switch (cinfo->out_color_space) { |
| case JCS_GRAYSCALE: |
| cinfo->out_color_components = 1; |
| if (cinfo->jpeg_color_space == JCS_GRAYSCALE || |
| cinfo->jpeg_color_space == JCS_YCbCr) { |
| cconvert->pub.color_convert = grayscale_convert; |
| /* For color->grayscale conversion, only the Y (0) component is needed */ |
| for (ci = 1; ci < cinfo->num_components; ci++) |
| cinfo->comp_info[ci].component_needed = FALSE; |
| } else |
| ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); |
| break; |
| |
| case JCS_RGB: |
| case JCS_EXT_RGB: |
| case JCS_EXT_RGBX: |
| case JCS_EXT_BGR: |
| case JCS_EXT_BGRX: |
| case JCS_EXT_XBGR: |
| case JCS_EXT_XRGB: |
| cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space]; |
| if (cinfo->jpeg_color_space == JCS_YCbCr) { |
| if (jsimd_can_ycc_rgb()) |
| cconvert->pub.color_convert = jsimd_ycc_rgb_convert; |
| else { |
| cconvert->pub.color_convert = ycc_rgb_convert; |
| build_ycc_rgb_table(cinfo); |
| } |
| } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) { |
| cconvert->pub.color_convert = gray_rgb_convert; |
| } else if (cinfo->jpeg_color_space == cinfo->out_color_space && |
| rgb_pixelsize[cinfo->out_color_space] == 3) { |
| cconvert->pub.color_convert = null_convert; |
| } else |
| ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); |
| break; |
| |
| case JCS_CMYK: |
| cinfo->out_color_components = 4; |
| if (cinfo->jpeg_color_space == JCS_YCCK) { |
| cconvert->pub.color_convert = ycck_cmyk_convert; |
| build_ycc_rgb_table(cinfo); |
| } else if (cinfo->jpeg_color_space == JCS_CMYK) { |
| cconvert->pub.color_convert = null_convert; |
| } else |
| ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); |
| break; |
| |
| default: |
| /* Permit null conversion to same output space */ |
| if (cinfo->out_color_space == cinfo->jpeg_color_space) { |
| cinfo->out_color_components = cinfo->num_components; |
| cconvert->pub.color_convert = null_convert; |
| } else /* unsupported non-null conversion */ |
| ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); |
| break; |
| } |
| |
| if (cinfo->quantize_colors) |
| cinfo->output_components = 1; /* single colormapped output component */ |
| else |
| cinfo->output_components = cinfo->out_color_components; |
| } |