Correct range brackets for antialias to integer graymap conversion

diff --git a/pctb/Makefile b/pctb/Makefile
index d99bb253576d88ea3026e67091a84401aa4c894d..6ebc48decfff7636e4dc52a6a3da01c2c22f8271 100644 (file)
--- a/pctb/Makefile
+++ b/pctb/Makefile
@@ -37,7 +37,7 @@ all: $(TARGETS)
 
 CONVERT_OBJS= convert.o ocr.o pages.o structure.o common.o rgbimage.o resolve.o
 
-ypp-commodities: $(CONVERT_OBJS) -lnetpbm -lXtst -lX11 -lpcre
+ypp-commodities: $(CONVERT_OBJS) -lnetpbm -lXtst -lX11 -lpcre -lm
        $(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LDLIBS)
 
 $(CONVERT_OBJS): ocr.h convert.h structure.h common.h

diff --git a/pctb/common.h b/pctb/common.h
index d4464bdbefa4adf958d8619d5d2b63ef8c3ab88d..fe87e16bbb566525a166bce6f5e3a7384a32fca2 100644 (file)
--- a/pctb/common.h
+++ b/pctb/common.h
@@ -32,6 +32,7 @@
 
 #include <locale.h>
 #include <stdarg.h>
+#include <math.h>
 #include <stdio.h>
 #include <errno.h>
 #include <assert.h>

diff --git a/pctb/structure.c b/pctb/structure.c
index 2bb6429602fdc790f6fb76a87c5a23e47c06f638..200b86ea43c28b5e3a0bd58a5f299be8ed2be941 100644 (file)
--- 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;
   }