1 /* 2 * jdcolext.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * libjpeg-turbo Modifications: 7 * Copyright (C) 2009, 2011, 2015, D. R. Commander. 8 * For conditions of distribution and use, see the accompanying README.ijg 9 * file. 10 * 11 * This file contains output colorspace conversion routines. 12 */ 13 14 15 /* This file is included by jdcolor.c */ 16 17 18 /* 19 * Convert some rows of samples to the output colorspace. 20 * 21 * Note that we change from noninterleaved, one-plane-per-component format 22 * to interleaved-pixel format. The output buffer is therefore three times 23 * as wide as the input buffer. 24 * A starting row offset is provided only for the input buffer. The caller 25 * can easily adjust the passed output_buf value to accommodate any row 26 * offset required on that side. 27 */ 28 29 INLINE 30 LOCAL(void) 31 ycc_rgb_convert_internal(j_decompress_ptr cinfo, JSAMPIMAGE input_buf, 32 JDIMENSION input_row, JSAMPARRAY output_buf, 33 int num_rows) 34 { 35 my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert; 36 register int y, cb, cr; 37 register JSAMPROW outptr; 38 register JSAMPROW inptr0, inptr1, inptr2; 39 register JDIMENSION col; 40 JDIMENSION num_cols = cinfo->output_width; 41 /* copy these pointers into registers if possible */ 42 register JSAMPLE *range_limit = cinfo->sample_range_limit; 43 register int *Crrtab = cconvert->Cr_r_tab; 44 register int *Cbbtab = cconvert->Cb_b_tab; 45 register JLONG *Crgtab = cconvert->Cr_g_tab; 46 register JLONG *Cbgtab = cconvert->Cb_g_tab; 47 SHIFT_TEMPS 48 49 while (--num_rows >= 0) { 50 inptr0 = input_buf[0][input_row]; 51 inptr1 = input_buf[1][input_row]; 52 inptr2 = input_buf[2][input_row]; 53 input_row++; 54 outptr = *output_buf++; 55 for (col = 0; col < num_cols; col++) { 56 y = GETJSAMPLE(inptr0[col]); 57 cb = GETJSAMPLE(inptr1[col]); 58 cr = GETJSAMPLE(inptr2[col]); 59 /* Range-limiting is essential due to noise introduced by DCT losses. */ 60 outptr[RGB_RED] = range_limit[y + Crrtab[cr]]; 61 outptr[RGB_GREEN] = range_limit[y + 62 ((int)RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], 63 SCALEBITS))]; 64 outptr[RGB_BLUE] = range_limit[y + Cbbtab[cb]]; 65 /* Set unused byte to 0xFF so it can be interpreted as an opaque */ 66 /* alpha channel value */ 67 #ifdef RGB_ALPHA 68 outptr[RGB_ALPHA] = 0xFF; 69 #endif 70 outptr += RGB_PIXELSIZE; 71 } 72 } 73 } 74 75 76 /* 77 * Convert grayscale to RGB: just duplicate the graylevel three times. 78 * This is provided to support applications that don't want to cope 79 * with grayscale as a separate case. 80 */ 81 82 INLINE 83 LOCAL(void) 84 gray_rgb_convert_internal(j_decompress_ptr cinfo, JSAMPIMAGE input_buf, 85 JDIMENSION input_row, JSAMPARRAY output_buf, 86 int num_rows) 87 { 88 register JSAMPROW inptr, outptr; 89 register JDIMENSION col; 90 JDIMENSION num_cols = cinfo->output_width; 91 92 while (--num_rows >= 0) { 93 inptr = input_buf[0][input_row++]; 94 outptr = *output_buf++; 95 for (col = 0; col < num_cols; col++) { 96 /* We can dispense with GETJSAMPLE() here */ 97 outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col]; 98 /* Set unused byte to 0xFF so it can be interpreted as an opaque */ 99 /* alpha channel value */ 100 #ifdef RGB_ALPHA 101 outptr[RGB_ALPHA] = 0xFF; 102 #endif 103 outptr += RGB_PIXELSIZE; 104 } 105 } 106 } 107 108 109 /* 110 * Convert RGB to extended RGB: just swap the order of source pixels 111 */ 112 113 INLINE 114 LOCAL(void) 115 rgb_rgb_convert_internal(j_decompress_ptr cinfo, JSAMPIMAGE input_buf, 116 JDIMENSION input_row, JSAMPARRAY output_buf, 117 int num_rows) 118 { 119 register JSAMPROW inptr0, inptr1, inptr2; 120 register JSAMPROW outptr; 121 register JDIMENSION col; 122 JDIMENSION num_cols = cinfo->output_width; 123 124 while (--num_rows >= 0) { 125 inptr0 = input_buf[0][input_row]; 126 inptr1 = input_buf[1][input_row]; 127 inptr2 = input_buf[2][input_row]; 128 input_row++; 129 outptr = *output_buf++; 130 for (col = 0; col < num_cols; col++) { 131 /* We can dispense with GETJSAMPLE() here */ 132 outptr[RGB_RED] = inptr0[col]; 133 outptr[RGB_GREEN] = inptr1[col]; 134 outptr[RGB_BLUE] = inptr2[col]; 135 /* Set unused byte to 0xFF so it can be interpreted as an opaque */ 136 /* alpha channel value */ 137 #ifdef RGB_ALPHA 138 outptr[RGB_ALPHA] = 0xFF; 139 #endif 140 outptr += RGB_PIXELSIZE; 141 } 142 } 143 } 144