| | 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 "imager.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, unsigned char (*maps)[256], unsigned int mask) { |
| | 39 | i_color *vals; |
| | 40 | i_img_dim x, y; |
| | 41 | int i, ch; |
| | 42 | int minset = -1, maxset = 0; |
| | 43 | |
| | 44 | mm_log((1,"i_map(im %p, maps %p, chmask %u)\n", im, maps, mask)); |
| | 45 | |
| | 46 | if (!mask) return; /* nothing to do here */ |
| | 47 | |
| | 48 | for(i=0; i<im->channels; i++) { |
| | 49 | if (mask & (1<<i)) { |
| | 50 | if (minset == -1) minset = i; |
| | 51 | maxset = i; |
| | 52 | } |
| | 53 | } |
| | 54 | |
| | 55 | mm_log((1, "minset=%d maxset=%d\n", minset, maxset)); |
| | 56 | |
| | 57 | if (minset == -1) |
| | 58 | return; |
| | 59 | |
| | 60 | vals = mymalloc(sizeof(i_color) * im->xsize); |
| | 61 | |
| | 62 | for (y = 0; y < im->ysize; ++y) { |
| | 63 | i_glin(im, 0, im->xsize, y, vals); |
| | 64 | for (x = 0; x < im->xsize; ++x) { |
| | 65 | for(ch = minset; ch<=maxset; ch++) { |
| | 66 | if (!(mask & (1 << ch))) |
| | 67 | continue; |
| | 68 | vals[x].channel[ch] = maps[ch][vals[x].channel[ch]]; |
| | 69 | } |
| | 70 | } |
| | 71 | i_plin(im, 0, im->xsize, y, vals); |
| | 72 | } |
| | 73 | myfree(vals); |
| | 74 | } |
| | 75 | |
| | 76 | /* |
| | 77 | =back |
| | 78 | |
| | 79 | =head1 SEE ALSO |
| | 80 | |
| | 81 | Imager(3) |
| | 82 | |
| | 83 | =head1 AUTHOR |
| | 84 | |
| | 85 | Arnar M. Hrafnkelsson <addi@umich.edu> |
| | 86 | |
| | 87 | =cut |
| | 88 | */ |
projects / imager.git / blame_incremental