1/* 2 * jccolext.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1996, Thomas G. Lane. 6 * libjpeg-turbo Modifications: 7 * Copyright (C) 2009-2012, D. R. Commander. 8 * For conditions of distribution and use, see the accompanying README file. 9 * 10 * This file contains input colorspace conversion routines. 11 */ 12 13 14/* This file is included by jccolor.c */ 15 16 17/* 18 * Convert some rows of samples to the JPEG colorspace. 19 * 20 * Note that we change from the application's interleaved-pixel format 21 * to our internal noninterleaved, one-plane-per-component format. 22 * The input buffer is therefore three times as wide as the output buffer. 23 * 24 * A starting row offset is provided only for the output buffer. The caller 25 * can easily adjust the passed input_buf value to accommodate any row 26 * offset required on that side. 27 */ 28 29INLINE 30LOCAL(void) 31rgb_ycc_convert_internal (j_compress_ptr cinfo, 32 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 33 JDIMENSION output_row, int num_rows) 34{ 35 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 36 register int r, g, b; 37 register INT32 * ctab = cconvert->rgb_ycc_tab; 38 register JSAMPROW inptr; 39 register JSAMPROW outptr0, outptr1, outptr2; 40 register JDIMENSION col; 41 JDIMENSION num_cols = cinfo->image_width; 42 43 while (--num_rows >= 0) { 44 inptr = *input_buf++; 45 outptr0 = output_buf[0][output_row]; 46 outptr1 = output_buf[1][output_row]; 47 outptr2 = output_buf[2][output_row]; 48 output_row++; 49 for (col = 0; col < num_cols; col++) { 50 r = GETJSAMPLE(inptr[RGB_RED]); 51 g = GETJSAMPLE(inptr[RGB_GREEN]); 52 b = GETJSAMPLE(inptr[RGB_BLUE]); 53 inptr += RGB_PIXELSIZE; 54 /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations 55 * must be too; we do not need an explicit range-limiting operation. 56 * Hence the value being shifted is never negative, and we don't 57 * need the general RIGHT_SHIFT macro. 58 */ 59 /* Y */ 60 outptr0[col] = (JSAMPLE) 61 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) 62 >> SCALEBITS); 63 /* Cb */ 64 outptr1[col] = (JSAMPLE) 65 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF]) 66 >> SCALEBITS); 67 /* Cr */ 68 outptr2[col] = (JSAMPLE) 69 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF]) 70 >> SCALEBITS); 71 } 72 } 73} 74 75 76/**************** Cases other than RGB -> YCbCr **************/ 77 78 79/* 80 * Convert some rows of samples to the JPEG colorspace. 81 * This version handles RGB->grayscale conversion, which is the same 82 * as the RGB->Y portion of RGB->YCbCr. 83 * We assume rgb_ycc_start has been called (we only use the Y tables). 84 */ 85 86INLINE 87LOCAL(void) 88rgb_gray_convert_internal (j_compress_ptr cinfo, 89 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 90 JDIMENSION output_row, int num_rows) 91{ 92 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 93 register int r, g, b; 94 register INT32 * ctab = cconvert->rgb_ycc_tab; 95 register JSAMPROW inptr; 96 register JSAMPROW outptr; 97 register JDIMENSION col; 98 JDIMENSION num_cols = cinfo->image_width; 99 100 while (--num_rows >= 0) { 101 inptr = *input_buf++; 102 outptr = output_buf[0][output_row]; 103 output_row++; 104 for (col = 0; col < num_cols; col++) { 105 r = GETJSAMPLE(inptr[RGB_RED]); 106 g = GETJSAMPLE(inptr[RGB_GREEN]); 107 b = GETJSAMPLE(inptr[RGB_BLUE]); 108 inptr += RGB_PIXELSIZE; 109 /* Y */ 110 outptr[col] = (JSAMPLE) 111 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) 112 >> SCALEBITS); 113 } 114 } 115} 116 117 118/* 119 * Convert some rows of samples to the JPEG colorspace. 120 * This version handles extended RGB->plain RGB conversion 121 */ 122 123INLINE 124LOCAL(void) 125rgb_rgb_convert_internal (j_compress_ptr cinfo, 126 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 127 JDIMENSION output_row, int num_rows) 128{ 129 register JSAMPROW inptr; 130 register JSAMPROW outptr0, outptr1, outptr2; 131 register JDIMENSION col; 132 JDIMENSION num_cols = cinfo->image_width; 133 134 while (--num_rows >= 0) { 135 inptr = *input_buf++; 136 outptr0 = output_buf[0][output_row]; 137 outptr1 = output_buf[1][output_row]; 138 outptr2 = output_buf[2][output_row]; 139 output_row++; 140 for (col = 0; col < num_cols; col++) { 141 outptr0[col] = GETJSAMPLE(inptr[RGB_RED]); 142 outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]); 143 outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]); 144 inptr += RGB_PIXELSIZE; 145 } 146 } 147} 148