[sixel] work out restore_band() #2573

src/lib/sixel.c

@@ -1594,30 +1594,43 @@ int sixel_init(int fd){
   return sixel_init_core("\e[?8452h", fd);
 }
 
+// rebuild the portion of some cell which is within this band, having stored
+// the pixels into the auxvec when the cell was wiped (and updated them if we
+// loaded another frame). we go through the auxvec to the right and down,
+// within the area covered by our band. if the entry is transparent, do
+// nothing. otherwise, it is some color; collect other instances of the color,
+// marking them transparent as we do so, and update that color's band. in
+// the worst case (all pixels different colors), this will be p^2 =\ FIXME.
+// .
+// returns the number of source-transparent pixels (i.e. pixels which weren't
+// restored), which will be used to update the TAM state.
 static inline int
 restore_band(sixelmap* smap, int band, int startx, int endx,
-             int starty, int endy, int dimx, int cellpxy, int cellpxx,
+             int starty, int endy, int cellpxy, int cellpxx,
              uint8_t* auxvec){
+  int restored = 0;
+  const int sy = band * 6 < starty ? starty - band * 6 : 0;
+  const int ey = (band + 1) * 6 > endy ? 6 - ((band + 1) * 6 - endy) : 6;
+  const int width = endx - startx;
+  const int height = ey - sy;
+  const int totalpixels = width * height;
+fprintf(stderr, "RESTORING band %d (%d->%d (%d->%d), %d->%d) %d pixels\n", band, sy, ey, starty, endy, startx, endx, totalpixels);
+  int yoff = sy % cellpxy; // we start off on this row of the auxvec
+  for(int dy = 0 ; sy + dy < ey ; ++dy){
+fprintf(stderr, "looking at line %d (auxvec row %d, dy %d)\n", sy + dy, yoff, dy);
+  }
   (void)smap;
-  (void)band;
-  (void)startx;
-  (void)endx;
-  (void)starty;
-  (void)endy;
-  (void)dimx;
-  (void)cellpxy;
   (void)cellpxx;
   (void)auxvec;
-  // FIXME
-  return 0;
+  return totalpixels - restored;
 }
 
 // only called for cells in SPRIXCELL_ANNIHILATED[_TRANS]. just post to
 // wipes_outstanding, so the Sixel gets regenerated the next render cycle,
 // just like wiping. this is necessary due to the complex nature of
 // modifying a Sixel -- we want to do them all in one batch.
 int sixel_rebuild(sprixel* s, int ycell, int xcell, uint8_t* auxvec){
-//fprintf(stderr, "REBUILDING %d/%d\n", ycell, xcell);
+fprintf(stderr, "REBUILDING %d/%d\n", ycell, xcell);
   if(auxvec == NULL){
     return -1;
   }
@@ -1641,22 +1654,18 @@ int sixel_rebuild(sprixel* s, int ycell, int xcell, uint8_t* auxvec){
   // walk through each color, and wipe the necessary sixels from each band
   int w = 0;
   for(int b = startband ; b < endband ; ++b){
-    w += restore_band(smap, b, startx, endx, starty, endy, s->pixx,
+    w += restore_band(smap, b, startx, endx, starty, endy,
                       cellpxy, cellpxx, auxvec);
   }
   s->wipes_outstanding = true;
-  // FIXME need to set this back up...how? return transparent count from
-  // restore_band(), and sum them up?
-  sprixcell_e newstate = SPRIXCELL_OPAQUE_SIXEL; // FIXME incorrect!
-  /*
-  if(transparent == cellpxx * cellpxy){
+  sprixcell_e newstate;
+  if(w == cellpxx * cellpxy){
     newstate = SPRIXCELL_TRANSPARENT;
-  }else if(transparent){
+  }else if(w){
     newstate = SPRIXCELL_MIXED_SIXEL;
   }else{
     newstate = SPRIXCELL_OPAQUE_SIXEL;
   }
-  */
   s->n->tam[s->dimx * ycell + xcell].state = newstate;
   return 1;
 }