pnmoutline.c

   1 #include <pam.h>
   2 #include <string.h>
   3
   4 struct pam inpam, outpam;
   5 tuple *inrows[3];
   6 tuple *outrow;
   7
   8 void
   9 row_fill_black(struct pam *p, tuple *row)
  10 {
  11         int i, j;
  12
  13         for(i=0; i<p->width; i++)
  14                 for(j=0; j<3; j++)
  15                         row[i][j]=0;
  16 }
  17
  18 int
  19 is_black(unsigned int row, unsigned int column)
  20 {
  21
  22         sample *s = inrows[row][column];
  23         if(s[0]==0 && s[1]==0 && s[2]==0) return ~0;
  24         else return 0;
  25 }
  26
  27 int
  28 is_edge(unsigned int column)
  29 {
  30         unsigned int n = 0;
  31         if(is_black(0,column)) n++;
  32         if(is_black(2,column)) n++;
  33         if(column == 0 || is_black(1, column-1)) n++;
  34         if(column == outpam.width-1 || is_black(1, column+1)) n++;
  35         return n>1 && n<4;
  36 }
  37
  38 void
  39 set_black(unsigned int column)
  40 {
  41         sample *s = outrow[column];
  42         s[0]=0; s[1]=0; s[2]=0;
  43 }
  44
  45 void
  46 set_white(unsigned int column)
  47 {
  48         sample *s = outrow[column];
  49         s[0]=255; s[1]=255; s[2]=255;
  50 }
  51
  52 void
  53 copy_tuple(sample *dest, sample *src)
  54 {
  55         dest[0] = src[0];
  56         dest[1] = src[1];
  57         dest[2] = src[2];
  58 }
  59
  60 void
  61 copy_row(struct pam *p, tuple *dest, tuple *src)
  62 {
  63         int i;
  64
  65         for(i=0; i<p->width; i++) copy_tuple(dest[i], src[i]);
  66 }
  67
  68 void
  69 next_row(unsigned int read)
  70 {
  71         copy_row(&outpam, inrows[0], inrows[1]);
  72         copy_row(&outpam, inrows[1], inrows[2]);
  73         /*
  74         memcpy(inrows[0], inrows[1], outpam.width*sizeof(sample)*3);
  75         memcpy(inrows[1], inrows[2], outpam.width*sizeof(sample)*3);
  76         */
  77         if(read) pnm_readpamrow(&inpam, inrows[2]+1);
  78         else row_fill_black(&outpam, inrows[2]);
  79 }
  80
  81
  82 int
  83 main(int argc, char **argv)
  84 {
  85         unsigned int row,column,i;
  86
  87         pnm_init(&argc, argv);
  88         pnm_readpaminit(stdin, &inpam, sizeof(struct pam));
  89
  90         outpam = inpam;
  91         outpam.width+=2; outpam.height+=2;
  92         outpam.file = stdout;
  93         pnm_writepaminit(&outpam);
  94
  95         for(i=0; i<3; i++) {
  96                 inrows[i] = pnm_allocpamrow(&outpam);
  97                 row_fill_black(&outpam, inrows[i]);
  98         }
  99
 100         outrow = pnm_allocpamrow(&outpam);
 101
 102         for(row=0; row < outpam.height; row++) {
 103                 next_row(row < inpam.height);
 104                 for(column=0; column<outpam.width; column++) {
 105                         if(is_black(1,column)) {
 106                                 if(is_edge(column)) set_black(column);
 107                                 else set_white(column);
 108                         } else copy_tuple(outrow[column], inrows[1][column]);
 109                 }
 110                 pnm_writepamrow(&outpam, outrow);
 111         }
 112
 113         pnm_freepamrow(outrow);
 114         for(i=0; i<3; i++) pnm_freepamrow(inrows[i]);
 115         return 0;
 116 }