X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~yarrgweb/git?a=blobdiff_plain;f=pctb%2Fstructure.c;h=200b86ea43c28b5e3a0bd58a5f299be8ed2be941;hb=065b523c45b707e7b4f49a9d976f901f8a6e9061;hp=2bb6429602fdc790f6fb76a87c5a23e47c06f638;hpb=ba2185d0ed58f86a39a374bff01d1251da20b339;p=ypp-sc-tools.web-live.git

diff --git a/pctb/structure.c b/pctb/structure.c
index 2bb6429..200b86e 100644
--- a/pctb/structure.c
+++ b/pctb/structure.c
@@ -484,7 +484,15 @@ static void find_table_entry(Rect commod, int colno, Rect *cell) {
 	 colno, cell->tl.x,cell->tl.y, cell->br.x,cell->br.y,
 	 bg_count, light_count, dark_count);
   
-  Rgb foreground= light_count ? 0xffffffU : 0;
+  Rgb foreground;
+  double fg_extra;
+  if (light_count) {
+    foreground= 0xffffffU;
+    fg_extra= +1;
+  } else {
+    foreground= 0;
+    fg_extra= -1;
+  }
   int monochrome= 1;
 
   FOR_P_RECT(p,*cell) {
@@ -496,8 +504,8 @@ static void find_table_entry(Rect commod, int colno, Rect *cell) {
       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);
+	((double)here_chan    - (double)bg_chan) /
+	((fg_chan + fg_extra) - (double)bg_chan);
       alpha[i]= alpha_chan;
       alpha_mean += alpha_chan * (1/3.0);
     }
@@ -510,10 +518,11 @@ static void find_table_entry(Rect commod, int colno, Rect *cell) {
 	    MI(i);MRGB(here);MRGB(background);MRGB(foreground);
 	    MF(alpha_min);MF(alpha[i]);MF(alpha_max) );
 
-    MUST( 0 <= alpha_mean && alpha_mean <= 1,
+    MUST( 0 <= alpha_mean && alpha_mean < 0.999,
 	  MRGB(here);MRGB(background);MRGB(foreground);
-	  MF(alpha_mean) );
-    int here_int= AAMAXVAL*alpha_mean;
+	  MF(alpha_mean); MF(alpha[0]);MF(alpha[1]);MF(alpha[2]); );
+    int here_int= floor((AAMAXVAL+1)*alpha_mean);
+    assert(here_int <= AAMAXVAL);
     if (!(here_int==0 || here_int==AAMAXVAL)) monochrome=0;
     cim->d[p.y * cim->w + p.x]= '0' + here_int;
   }