DRC | b4570bb | 2011-09-07 06:31:00 +0000 | [diff] [blame] | 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 | } |