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| 1 /* |
| 2 * jccolext.c |
| 3 * |
| 4 * Copyright (C) 1991-1996, Thomas G. Lane. |
| 5 * Copyright (C) 2009-2011, D. R. Commander. |
| 6 * This file is part of the Independent JPEG Group's software. |
| 7 * For conditions of distribution and use, see the accompanying README file. |
| 8 * |
| 9 * This file contains input colorspace conversion routines. |
| 10 */ |
| 11 |
| 12 |
| 13 /* This file is included by jccolor.c */ |
| 14 |
| 15 |
| 16 /* |
| 17 * Convert some rows of samples to the JPEG colorspace. |
| 18 * |
| 19 * Note that we change from the application's interleaved-pixel format |
| 20 * to our internal noninterleaved, one-plane-per-component format. |
| 21 * The input buffer is therefore three times as wide as the output buffer. |
| 22 * |
| 23 * A starting row offset is provided only for the output buffer. The caller |
| 24 * can easily adjust the passed input_buf value to accommodate any row |
| 25 * offset required on that side. |
| 26 */ |
| 27 |
| 28 INLINE |
| 29 LOCAL(void) |
| 30 rgb_ycc_convert_internal (j_compress_ptr cinfo, |
| 31 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, |
| 32 JDIMENSION output_row, int num_rows) |
| 33 { |
| 34 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; |
| 35 register int r, g, b; |
| 36 register INT32 * ctab = cconvert->rgb_ycc_tab; |
| 37 register JSAMPROW inptr; |
| 38 register JSAMPROW outptr0, outptr1, outptr2; |
| 39 register JDIMENSION col; |
| 40 JDIMENSION num_cols = cinfo->image_width; |
| 41 |
| 42 while (--num_rows >= 0) { |
| 43 inptr = *input_buf++; |
| 44 outptr0 = output_buf[0][output_row]; |
| 45 outptr1 = output_buf[1][output_row]; |
| 46 outptr2 = output_buf[2][output_row]; |
| 47 output_row++; |
| 48 for (col = 0; col < num_cols; col++) { |
| 49 r = GETJSAMPLE(inptr[RGB_RED]); |
| 50 g = GETJSAMPLE(inptr[RGB_GREEN]); |
| 51 b = GETJSAMPLE(inptr[RGB_BLUE]); |
| 52 inptr += RGB_PIXELSIZE; |
| 53 /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations |
| 54 * must be too; we do not need an explicit range-limiting operation. |
| 55 * Hence the value being shifted is never negative, and we don't |
| 56 * need the general RIGHT_SHIFT macro. |
| 57 */ |
| 58 /* Y */ |
| 59 outptr0[col] = (JSAMPLE) |
| 60 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) |
| 61 >> SCALEBITS); |
| 62 /* Cb */ |
| 63 outptr1[col] = (JSAMPLE) |
| 64 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF]) |
| 65 >> SCALEBITS); |
| 66 /* Cr */ |
| 67 outptr2[col] = (JSAMPLE) |
| 68 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF]) |
| 69 >> SCALEBITS); |
| 70 } |
| 71 } |
| 72 } |
| 73 |
| 74 |
| 75 /**************** Cases other than RGB -> YCbCr **************/ |
| 76 |
| 77 |
| 78 /* |
| 79 * Convert some rows of samples to the JPEG colorspace. |
| 80 * This version handles RGB->grayscale conversion, which is the same |
| 81 * as the RGB->Y portion of RGB->YCbCr. |
| 82 * We assume rgb_ycc_start has been called (we only use the Y tables). |
| 83 */ |
| 84 |
| 85 INLINE |
| 86 LOCAL(void) |
| 87 rgb_gray_convert_internal (j_compress_ptr cinfo, |
| 88 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, |
| 89 JDIMENSION output_row, int num_rows) |
| 90 { |
| 91 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; |
| 92 register int r, g, b; |
| 93 register INT32 * ctab = cconvert->rgb_ycc_tab; |
| 94 register JSAMPROW inptr; |
| 95 register JSAMPROW outptr; |
| 96 register JDIMENSION col; |
| 97 JDIMENSION num_cols = cinfo->image_width; |
| 98 |
| 99 while (--num_rows >= 0) { |
| 100 inptr = *input_buf++; |
| 101 outptr = output_buf[0][output_row]; |
| 102 output_row++; |
| 103 for (col = 0; col < num_cols; col++) { |
| 104 r = GETJSAMPLE(inptr[RGB_RED]); |
| 105 g = GETJSAMPLE(inptr[RGB_GREEN]); |
| 106 b = GETJSAMPLE(inptr[RGB_BLUE]); |
| 107 inptr += RGB_PIXELSIZE; |
| 108 /* Y */ |
| 109 outptr[col] = (JSAMPLE) |
| 110 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) |
| 111 >> SCALEBITS); |
| 112 } |
| 113 } |
| 114 } |
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