projects / imager.git / blame
| Commit | Line | Data |
|---|---|---|
| 2df3535a AMH |
1 | /* |
| 2 | =head1 NAME | |
| 3 | ||
| 4 | map.c - inplace image mapping and related functionality | |
| 5 | ||
| 6 | =head1 SYNOPSIS | |
| 7 | ||
| 8 | i_map(srcimage, coeffs, outchans, inchans) | |
| 9 | ||
| 10 | =head1 DESCRIPTION | |
| 11 | ||
| 12 | Converts images from one format to another, typically in this case for | |
| 13 | converting from RGBA to greyscale and back. | |
| 14 | ||
| 15 | =over | |
| 16 | ||
| 17 | =cut | |
| 18 | */ | |
| 19 | ||
| 20 | #include "image.h" | |
| 21 | ||
| 22 | ||
| 23 | /* | |
| 24 | =item i_map(im, mapcount, maps, chmasks) | |
| 25 | ||
| 26 | maps im inplace into another image. | |
| 27 | ||
| 28 | Each map is a unsigned char array of 256 entries, its corresponding | |
| 29 | channel mask is the same numbered entry in the chmasks array. | |
| 30 | If two maps apply to the same channel then the second one is used. | |
| 31 | If no map applies to a channel then that channel is not altered. | |
| 32 | mapcount is the number of maps. | |
| 33 | ||
| 34 | =cut | |
| 35 | */ | |
| 36 | ||
| 37 | void | |
| 38 | i_map(i_img *im, int mapcount, unsigned char (*maps)[256], unsigned int *chmasks) { | |
| 39 | i_color *vals; | |
| 40 | int x, y; | |
| 41 | int mapno, i, ch; | |
| 42 | unsigned int mask = 0; | |
| 43 | unsigned char (**cmaps)[256]; | |
| 44 | int minset = -1, maxset; | |
| 45 | ||
| 46 | mm_log((1,"i_map(im %p, mapcount %d, maps %p, chmasks %p)\n", im, mapcount, maps, chmasks)); | |
| 47 | ||
| 48 | ||
| 49 | for(mapno=0; mapno<mapcount; mapno++) mask |=chmasks[mapno]; | |
| 50 | if (!mask) return; /* nothing to do here */ | |
| 51 | ||
| 52 | ||
| 53 | ||
| 54 | for(i=0; i<im->channels; i++) | |
| 55 | if (mask & (1<<i)) { | |
| 56 | if (minset == -1) minset = i; | |
| 57 | maxset = i; | |
| 58 | } | |
| 59 | ||
| 60 | cmaps = mymalloc(sizeof(unsigned char (*)[256])*im->channels); | |
| 61 | memset(cmaps, 0, sizeof(unsigned char (*)[256])*im->channels); | |
| 62 | for(mapno=0; mapno<mapcount; mapno++) | |
| 63 | for(ch=0; ch<im->channels; ch++) | |
| 64 | if (chmasks[i] & (1<<ch)) cmaps[ch] = &maps[mapno]; | |
| 65 | ||
| 66 | vals = mymalloc(sizeof(i_color) * im->xsize); | |
| 67 | for (y = 0; y < im->ysize; ++y) { | |
| 68 | i_glin(im, 0, im->xsize, y, vals); | |
| 69 | for (x = 0; x < im->xsize; ++x) { | |
| 70 | int lidx = x * im->channels; | |
| 71 | for(ch = minset; ch<=maxset; ch++) { | |
| 72 | if (!cmaps[ch]) continue; | |
| 73 | vals[lidx].channel[ch] = (*cmaps[ch])[vals[lidx].channel[ch]]; | |
| 74 | } | |
| 75 | } | |
| 76 | i_plin(im, 0, im->xsize, y, vals); | |
| 77 | } | |
| 78 | myfree(cmaps); | |
| 79 | myfree(vals); | |
| 80 | } | |
| 81 | ||
| 82 | /* | |
| 83 | =back | |
| 84 | ||
| 85 | =head1 SEE ALSO | |
| 86 | ||
| 87 | Imager(3) | |
| 88 | ||
| 89 | =head1 AUTHOR | |
| 90 | ||
| 91 | Arnar M. Hrafnkelsson <addi@umich.edu> | |
| 92 | ||
| 93 | =cut | |
| 94 | */ |