+static void find_table_entry(Rect commod, int colno, Rect *cell) {
+ cell->tl.y= commod.tl.y;
+ cell->br.y= commod.br.y;
+ cell->tl.x= !colno ? commod.tl.x : colrightx[colno-1]+2;
+ cell->br.x= colrightx[colno];
+ debug_rect("cell", colno, *cell);
+
+ const RgbImage *ri= cim->rgb;
+
+ Rgb background= ri_rgb(ri, cell->br.x, cell->br.y);
+ long bg_count=0, white_count=0, black_count=0;
+ Point p;
+ FOR_P_RECT(p,*cell) {
+ Rgb here= ri_rgb(ri, p.x, p.y);
+ if (here == background) bg_count++;
+ else if (here == 0) black_count++;
+ else if (here == 0xffffffU) white_count++;
+ }
+ long total_count= RECT_W(*cell) * RECT_H(*cell);
+ MUST( bg_count > 8*total_count / 10,
+ MR(*cell);MIL(bg_count);MIL(white_count);MIL(black_count) );
+ if (bg_count == total_count)
+ return;
+
+ MUST( !!black_count != !!white_count,
+ MR(*cell);MIL(bg_count);MIL(white_count);MIL(black_count) );
+
+ debugf("TABLEENTRY col=%d %d,%d..%d,%d bg=%ld white=%ld black=%ld\n",
+ colno, cell->tl.x,cell->tl.y, cell->br.x,cell->br.y,
+ bg_count, white_count, black_count);
+
+ Rgb foreground= white_count ? 0xffffffU : 0;
+ int monochrome= 1;
+
+ FOR_P_RECT(p,*cell) {
+ Rgb here= ri_rgb(ri, p.x, p.y);
+ double alpha[3], alpha_mean=0;
+ int i;
+ for (i=0; i<3; i++) {
+ unsigned char here_chan= here >> (i*8);
+ unsigned char bg_chan= background >> (i*8);
+ unsigned char fg_chan= foreground >> (i*8);
+ double alpha_chan=
+ ((double)here_chan - (double)bg_chan) /
+ ((double)fg_chan - (double)bg_chan);
+ alpha[i]= alpha_chan;
+ alpha_mean += alpha_chan * (1/3.0);
+ }
+
+ double thresh= 1.0/AAMAXVAL;
+ double alpha_min= alpha_mean - thresh;
+ double alpha_max= alpha_mean + thresh;
+ for (i=0; i<3; i++)
+ MUST( alpha_min <= alpha[i] && alpha[i] <= alpha_max,
+ MI(i);MRGB(here);MRGB(background);MRGB(foreground);
+ MF(alpha_min);MF(alpha[i]);MF(alpha_max) );
+
+ MUST( 0 <= alpha_mean && alpha_mean <= 1,
+ MRGB(here);MRGB(background);MRGB(foreground);
+ MF(alpha_mean) );
+ int here_int= AAMAXVAL*alpha_mean;
+ if (!(here_int==0 || here_int==AAMAXVAL)) monochrome=0;
+ cim->d[p.y * cim->w + p.x]= '0' + here_int;
+ }
+
+ debug_rect("cell0M", colno, *cell);
+
+ require_rectangle_r(*cell, "0123456789", __LINE__);