projects / imager.git / blame
| Commit | Line | Data |
|---|---|---|
| f5991c03 TC |
1 | /* |
| 2 | =head1 NAME | |
| 3 | ||
| 4 | convert.c - image conversions | |
| 5 | ||
| 6 | =head1 SYNOPSIS | |
| 7 | ||
| 8 | i_convert(outimage, srcimage, coeff, 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_convert(im, src, coeff, outchan, inchan) | |
| 25 | ||
| 26 | Converts the image src into another image. | |
| 27 | ||
| 28 | coeff contains the co-efficients of an outchan x inchan matrix, for | |
| 29 | each output pixel: | |
| 30 | ||
| 31 | coeff[0], coeff[1] ... | |
| 32 | im[x,y] = [ coeff[inchan], coeff[inchan+1]... ] * [ src[x,y], 1] | |
| 33 | ... coeff[inchan*outchan-1] | |
| 34 | ||
| 35 | If im has the wrong number of channels or is the wrong size then | |
| 36 | i_convert() will re-create it. | |
| 37 | ||
| 38 | =cut | |
| 39 | */ | |
| 40 | ||
| 41 | int | |
| 42 | i_convert(i_img *im, i_img *src, float *coeff, int outchan, int inchan) | |
| 43 | { | |
| 44 | i_color *vals; | |
| 45 | int x, y; | |
| 46 | int i, j; | |
| 47 | int ilimit, jlimit; | |
| 48 | double work[MAXCHANNELS]; | |
| 49 | ||
| 50 | mm_log((1,"i_convert(im* 0x%x, src, 0x%x, coeff 0x%x,outchan %d, inchan %d)\n",im,src, coeff,outchan, inchan)); | |
| 51 | ||
| 52 | i_clear_error(); | |
| 53 | ||
| 54 | ilimit = inchan; | |
| 55 | if (ilimit > src->channels) | |
| 56 | ilimit = src->channels; | |
| 57 | if (outchan > MAXCHANNELS) { | |
| 58 | i_push_error(0, "cannot have outchan > MAXCHANNELS"); | |
| 59 | return 0; | |
| 60 | } | |
| 61 | ||
| 62 | /* first check the output image */ | |
| 63 | if (im->channels != outchan || im->xsize != src->xsize | |
| 64 | || im->ysize != src->ysize) { | |
| 65 | i_img_empty_ch(im, src->xsize, src->ysize, outchan); | |
| 66 | } | |
| 67 | vals = mymalloc(sizeof(i_color) * src->xsize); | |
| 68 | for (y = 0; y < src->ysize; ++y) { | |
| 69 | i_glin(src, 0, src->xsize, y, vals); | |
| 70 | for (x = 0; x < src->xsize; ++x) { | |
| 71 | for (j = 0; j < outchan; ++j) { | |
| 72 | work[j] = 0; | |
| 73 | for (i = 0; i < ilimit; ++i) { | |
| 74 | work[j] += coeff[i+inchan*j] * vals[x].channel[i]; | |
| 75 | } | |
| 76 | if (i < inchan) { | |
| 77 | work[j] += coeff[i+inchan*j] * 255.9; | |
| 78 | } | |
| 79 | } | |
| 80 | for (j = 0; j < outchan; ++j) { | |
| 81 | if (work[j] < 0) | |
| 82 | vals[x].channel[j] = 0; | |
| 83 | else if (work[j] >= 256) | |
| 84 | vals[x].channel[j] = 255; | |
| 85 | else | |
| 86 | vals[x].channel[j] = work[j]; | |
| 87 | } | |
| 88 | } | |
| 89 | i_plin(im, 0, src->xsize, y, vals); | |
| 90 | } | |
| 91 | myfree(vals); | |
| 92 | return 1; | |
| 93 | } | |
| 94 | ||
| 95 | /* | |
| 96 | =back | |
| 97 | ||
| 98 | =head1 SEE ALSO | |
| 99 | ||
| 100 | Imager(3) | |
| 101 | ||
| 102 | =head1 AUTHOR | |
| 103 | ||
| 104 | Tony Cook <tony@develop-help.com> | |
| 105 | ||
| 106 | =cut | |
| 107 | */ |