diff --git a/CMakeLists.txt b/CMakeLists.txt
index 412e7d4e8..3785dd223 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -128,8 +128,8 @@ add_compile_options(-fno-signed-zeros -fno-trapping-math -fassociative-math)
 add_compile_options(-fno-math-errno -freciprocal-math -funsafe-math-optimizations)
 add_compile_options(-fexceptions -fstrict-aliasing)
 if(${USE_ASAN})
-add_compile_options(-fsanitize=undefined)
-add_link_options(-fsanitize=undefined)
+add_compile_options(-fsanitize=address)
+add_link_options(-fsanitize=address)
 endif()
 endif()
 
diff --git a/NEWS.md b/NEWS.md
index d07c9b8f6..f3f36901a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -12,8 +12,11 @@ rearrangements of Notcurses.
     deprecated functionality, ABI3 ought require small changes, if any.
 
 * 2.4.9 (not yet released)
+  * Added `ncnmetric()`, which uses `snprintf()` internally. `ncmetric()`
+    was reimplemented as a trivial wrapper around `ncnmetric()`.
   * `qprefix()`, `bprefix()`, and `iprefix()` have been renamed
     `ncqprefix()`, `ncbprefix()`, and `nciprefix()`, respectively.
+    The former forms have been deprecated, and will be removed in abi3.
   * `notcurses_mice_enable()` and `notcurses_mouse_disable()` replace
     `notcurses_mouse_enable()` and `notcurses_mouse_disable()`, which
     have been deprecated, and will be removed in ABI3.
diff --git a/USAGE.md b/USAGE.md
index a9e6ebcbf..4ddfc8007 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -451,7 +451,7 @@ are available for direct mode:
 // Read a (heap-allocated) newline-delimited chunk of text. Returns NULL on
 // failure. The NCDIRECT_OPTION_INHIBIT_CBREAK flag ought not be used together
 // with this function, or the line-editing keybindings cannot be honored.
-API char* ncdirect_readline(struct ncdirect* nc, const char* prompt);
+char* ncdirect_readline(struct ncdirect* nc, const char* prompt);
 
 int ncdirect_fg_rgb(struct ncdirect* nc, unsigned rgb);
 int ncdirect_bg_rgb(struct ncdirect* nc, unsigned rgb);
@@ -1674,8 +1674,8 @@ int ncplane_gradient2x1(struct ncplane* n, int y, int x, unsigned ylen,
 // remaining to the right and below, respectively. It is an error for any
 // coordinate to be outside the plane. Returns the number of cells set,
 // or -1 on failure.
-API int ncplane_format(struct ncplane* n, int y, int x, unsigned ylen,
-                       unsigned xlen, uint16_t stylemask);
+int ncplane_format(struct ncplane* n, int y, int x, unsigned ylen,
+                   unsigned xlen, uint16_t stylemask);
 
 // Set the given channels throughout the specified region, keeping content and
 // channels unchanged. The upper left corner is at 'x', 'y', and -1 may be
@@ -1684,9 +1684,9 @@ API int ncplane_format(struct ncplane* n, int y, int x, unsigned ylen,
 // remaining to the right and below, respectively. It is an error for any
 // coordinate to be outside the plane. Returns the number of cells set,
 // or -1 on failure.
-API int ncplane_stain(struct ncplane* n, int y, int x, unsigned ylen,
-                      unsigned xlen, uint64_t ul, uint64_t ur,
-                      uint64_t ll, uint64_t lr);
+int ncplane_stain(struct ncplane* n, int y, int x, unsigned ylen,
+                  unsigned xlen, uint64_t ul, uint64_t ur,
+                  uint64_t ll, uint64_t lr);
 ```
 
 My 14 year-old self would never forgive me if we didn't have sweet palette
diff --git a/include/notcurses/notcurses.h b/include/notcurses/notcurses.h
index 2edd80f30..d4eb69c7b 100644
--- a/include/notcurses/notcurses.h
+++ b/include/notcurses/notcurses.h
@@ -1807,7 +1807,7 @@ API void ncplane_center_abs(const struct ncplane* n, int* RESTRICT y,
 // Only glyphs from the specified ncblitset may be present. If 'pxdimy' and/or
 // 'pxdimx' are non-NULL, they will be filled in with the total pixel geometry.
 API ALLOC uint32_t* ncplane_as_rgba(const struct ncplane* n, ncblitter_e blit,
-                                    unsigned begy, unsigned begx,
+                                    int begy, int begx,
                                     unsigned leny, unsigned lenx,
                                     unsigned* pxdimy, unsigned* pxdimx)
   __attribute__ ((nonnull (1)));
@@ -2869,7 +2869,7 @@ API ALLOC struct ncvisual* ncvisual_from_palidx(const void* data, int rows,
 // Lengths of 0 are interpreted to mean "all available remaining area".
 API ALLOC struct ncvisual* ncvisual_from_plane(const struct ncplane* n,
                                                ncblitter_e blit,
-                                               unsigned begy, unsigned begx,
+                                               int begy, int begx,
                                                unsigned leny, unsigned lenx)
   __attribute__ ((nonnull (1)));
 
@@ -3366,6 +3366,12 @@ API const char* ncmetric(uintmax_t val, uintmax_t decimal, char* buf,
                          int omitdec, uintmax_t mult, int uprefix)
   __attribute__ ((nonnull (3)));
 
+// uses snprintf() internally with the argument 's' as its bound
+API const char* ncnmetric(uintmax_t val, size_t s, uintmax_t decimal,
+                          char* buf, int omitdec, uintmax_t mult,
+                          int uprefix)
+  __attribute__ ((nonnull (4)));
+
 // The number of columns is one fewer, as the STRLEN expressions must leave
 // an extra byte open in case 'µ' (U+00B5, 0xC2 0xB5) shows up. PREFIXCOLUMNS
 // is the maximum number of columns used by a mult == 1000 (standard)
@@ -3672,17 +3678,17 @@ API ALLOC struct ncmenu* ncmenu_create(struct ncplane* n, const ncmenu_options*
 API int ncmenu_unroll(struct ncmenu* n, int sectionidx);
 
 // Roll up any unrolled menu section, and hide the menu if using hiding.
-API int ncmenu_rollup(struct ncmenu* n);
+API int ncmenu_rollup(struct ncmenu* n) __attribute__ ((nonnull (1)));
 
 // Unroll the previous/next section (relative to current unrolled). If no
 // section is unrolled, the first section will be unrolled.
-API int ncmenu_nextsection(struct ncmenu* n);
-API int ncmenu_prevsection(struct ncmenu* n);
+API int ncmenu_nextsection(struct ncmenu* n) __attribute__ ((nonnull (1)));
+API int ncmenu_prevsection(struct ncmenu* n) __attribute__ ((nonnull (1)));
 
 // Move to the previous/next item within the currently unrolled section. If no
 // section is unrolled, the first section will be unrolled.
-API int ncmenu_nextitem(struct ncmenu* n);
-API int ncmenu_previtem(struct ncmenu* n);
+API int ncmenu_nextitem(struct ncmenu* n) __attribute__ ((nonnull (1)));
+API int ncmenu_previtem(struct ncmenu* n) __attribute__ ((nonnull (1)));
 
 // Disable or enable a menu item. Returns 0 if the item was found.
 API int ncmenu_item_set_status(struct ncmenu* n, const char* section,
@@ -4286,6 +4292,23 @@ API int ncplane_highgradient_sized(struct ncplane* n, uint32_t ul, uint32_t ur,
                                    uint32_t ll, uint32_t lr, int ylen, int xlen)
   __attribute__ ((deprecated));
 
+__attribute__ ((deprecated)) static inline const char*
+qprefix(uintmax_t val, uintmax_t decimal, char* buf, int omitdec){
+  return ncmetric(val, decimal, buf, omitdec, 1000, '\0');
+}
+
+// Mibi, kebi, gibibytes sans 'i' suffix. Use IPREFIXSTRLEN + 1.
+__attribute__ ((deprecated)) static inline const char*
+iprefix(uintmax_t val, uintmax_t decimal, char* buf, int omitdec){
+  return ncmetric(val, decimal, buf, omitdec, 1024, '\0');
+}
+
+// Mibi, kebi, gibibytes. Use BPREFIXSTRLEN + 1 and BPREFIXCOLUMNS.
+__attribute__ ((deprecated)) static inline const char*
+bprefix(uintmax_t val, uintmax_t decimal, char* buf, int omitdec){
+  return ncmetric(val, decimal, buf, omitdec, 1024, 'i');
+}
+
 #undef API
 #undef ALLOC
 
diff --git a/src/demo/hud.c b/src/demo/hud.c
index b7ac2980e..2d1b908dd 100644
--- a/src/demo/hud.c
+++ b/src/demo/hud.c
@@ -392,13 +392,13 @@ hud_print_finished(elem* list){
       if(ncplane_printf_yx(hud, line, 1, "%d", e->frames) < 0){
         return -1;
       }
-      char buf[PREFIXCOLUMNS];
-      ncmetric(e->totalns, NANOSECS_IN_SEC, buf, 0, 1000, '\0');
-      for(size_t x = 6 ; x < 14 - strlen(buf) ; ++x){
+      char buf[PREFIXCOLUMNS + 2];
+      ncnmetric(e->totalns, sizeof(buf), NANOSECS_IN_SEC, buf, 0, 1000, '\0');
+      for(int x = 6 ; x < 14 - ncstrwidth(buf) ; ++x){
         nccell ci = CELL_TRIVIAL_INITIALIZER;
         ncplane_putc_yx(hud, 1, x, &ci);
       }
-      if(ncplane_printf_yx(hud, line, 14 - strlen(buf), "%ss", buf) < 0){
+      if(ncplane_printf_yx(hud, line, 14 - ncstrwidth(buf), "%ss", buf) < 0){
         return -1;
       }
       if(ncplane_putstr_yx(hud, line, 16, e->name) < 0){
@@ -612,13 +612,14 @@ int demo_render(struct notcurses* nc){
     if(ncplane_printf_yx(hud, 1, 1, "%d", elems->frames) < 0){
       return -1;
     }
-    char buf[PREFIXCOLUMNS];
-    ncmetric(ns, NANOSECS_IN_SEC, buf, 0, 1000, '\0');
-    for(size_t x = 6 ; x < 14 - strlen(buf) ; ++x){
+    char buf[PREFIXCOLUMNS + 2];
+    ncnmetric(ns, sizeof(buf), NANOSECS_IN_SEC, buf, 0, 1000, '\0');
+    for(int x = 6 ; x < 14 - ncstrwidth(buf) ; ++x){
       nccell ci = CELL_TRIVIAL_INITIALIZER;
       ncplane_putc_yx(hud, 1, x, &ci);
     }
-    if(ncplane_printf_yx(hud, 1, 14 - strlen(buf), "%ss", buf) < 0){
+//fprintf(stderr, "[%s] %zu %d\n", buf, strlen(buf), ncstrwidth(buf));
+    if(ncplane_printf_yx(hud, 1, 14 - ncstrwidth(buf), "%ss", buf) < 0){
       return -1;
     }
     if(ncplane_putstr_yx(hud, 1, 16, elems->name) < 0){
diff --git a/src/demo/intro.c b/src/demo/intro.c
index 38819ccf5..487b847d5 100644
--- a/src/demo/intro.c
+++ b/src/demo/intro.c
@@ -124,7 +124,7 @@ int intro(struct notcurses* nc){
   if(!notcurses_canutf8(nc)){
     return 0;
   }
-  int rows, cols;
+  unsigned rows, cols;
   struct ncplane* ncp = notcurses_stddim_yx(nc, &rows, &cols);
   uint32_t ccul, ccur, ccll, cclr;
   ccul = ccur = ccll = cclr = 0;
diff --git a/src/demo/luigi.c b/src/demo/luigi.c
index ec13d2639..7a6bcdb11 100644
--- a/src/demo/luigi.c
+++ b/src/demo/luigi.c
@@ -146,7 +146,7 @@ int luigi_demo(struct notcurses* nc){
   if(!notcurses_canopen_images(nc)){
     return 0;
   }
-  int rows, cols;
+  unsigned rows, cols;
   char* map = find_data("megaman2.bmp");
   struct ncvisual* nv = ncvisual_from_file(map);
   free(map);
@@ -166,7 +166,7 @@ int luigi_demo(struct notcurses* nc){
   const int height = 32;
   int yoff = rows * 4 / 5 - height + 1; // tuned
   struct ncplane* lns[3];
-  int i;
+  unsigned i;
   struct ncplane* lastseen = NULL;
   for(i = 0 ; i < 3 ; ++i){
     struct ncplane_options nopts = {
diff --git a/src/demo/whiteout.c b/src/demo/whiteout.c
index 451020324..88955a140 100644
--- a/src/demo/whiteout.c
+++ b/src/demo/whiteout.c
@@ -509,14 +509,14 @@ int witherworm_demo(struct notcurses* nc){
           }
           int ulen = 0;
           int r;
-          //if(wcwidth(wcs) <= maxx - x){
+          if(wcwidth(wcs) <= (int)maxx - x){
             if((r = ncplane_putegc(n, &(*s)[idx], &ulen)) <= 0){
               if(ulen < 0){
                 return -1;
               }else if(ulen == 0){
                 break; // FIXME work around missing unicode
               }
-            //}
+            }
           }else{
             if((r = ncplane_putchar(n, '#')) < 1){
               return -1;
diff --git a/src/lib/fill.c b/src/lib/fill.c
index fe124cb0c..6a935c093 100644
--- a/src/lib/fill.c
+++ b/src/lib/fill.c
@@ -20,50 +20,58 @@ void ncplane_greyscale(ncplane *n){
 // success. so a return of 0 means there's no work to be done here, and N means
 // we did some work here, filling everything we could reach. out-of-plane is 0.
 static int
-ncplane_polyfill_recurse(ncplane* n, unsigned y, unsigned x, const nccell* c, const char* filltarg){
-  if(y >= (unsigned)n->leny || x >= (unsigned)n->lenx){
-    return 0; // not fillable
+ncplane_polyfill_inner(ncplane* n, unsigned y, unsigned x, const nccell* c, const char* filltarg){
+  struct topolyfill* stack = NULL;
+  if(create_polyfill_op(y, x, &stack) == NULL){
+    return -1;
   }
-  nccell* cur = &n->fb[nfbcellidx(n, y, x)];
-  const char* glust = nccell_extended_gcluster(n, cur);
+  int ret = 0;
+  do{
+    struct topolyfill* s = stack;
+    stack = stack->next;
+    y = s->y;
+    x = s->x;
+    nccell* cur = &n->fb[nfbcellidx(n, y, x)];
+    const char* glust = nccell_extended_gcluster(n, cur);
 //fprintf(stderr, "checking %d/%d (%s) for [%s]\n", y, x, glust, filltarg);
-  if(strcmp(glust, filltarg)){
-    return 0;
-  }
-  if(nccell_duplicate(n, cur, c) < 0){
-    return -1;
-  }
-  int r, ret = 1;
+    if(strcmp(glust, filltarg) == 0){
+      ++ret;
+      if(nccell_duplicate(n, cur, c) < 0){
+        // FIXME need free stack!
+        return -1;
+      }
 //fprintf(stderr, "blooming from %d/%d ret: %d\n", y, x, ret);
-  if(y){
-    if((r = ncplane_polyfill_recurse(n, y - 1, x, c, filltarg)) < 0){
-      return -1;
+      if(y){
+        if(create_polyfill_op(y - 1, x, &stack) == NULL){
+          return -1;
+        }
+      }
+      if(y + 1 < n->leny){
+        if(create_polyfill_op(y + 1, x, &stack) == NULL){
+          return -1;
+        }
+      }
+      if(x){
+        if(create_polyfill_op(y, x - 1, &stack) == NULL){
+          return -1;
+        }
+      }
+      if(x + 1 < n->lenx){
+        if(create_polyfill_op(y, x + 1, &stack) == NULL){
+          return -1;
+        }
+      }
     }
-    ret += r;
-  }
-  if((r = ncplane_polyfill_recurse(n, y + 1, x, c, filltarg)) < 0){
-    return -1;
-  }
-  ret += r;
-  if(x){
-    if((r = ncplane_polyfill_recurse(n, y, x - 1, c, filltarg)) < 0){
-      return -1;
-    }
-    ret += r;
-  }
-  if((r = ncplane_polyfill_recurse(n, y, x + 1, c, filltarg)) < 0){
-    return -1;
-  }
-  ret += r;
+    free(s);
+  }while(stack);
   return ret;
 }
 
 // at the initial step only, invalid ystart, xstart is an error, so explicitly check.
 int ncplane_polyfill_yx(ncplane* n, int ystart, int xstart, const nccell* c){
-  int ret = -1;
   if(ystart < 0){
     if(ystart != -1){
-      logerror("invalid ystart: %d\n", ystart);
+      logerror("invalid y: %d\n", ystart);
       return -1;
     }
     ystart = n->y;
@@ -71,7 +79,7 @@ int ncplane_polyfill_yx(ncplane* n, int ystart, int xstart, const nccell* c){
   unsigned y = ystart;
   if(xstart < 0){
     if(xstart != -1){
-      logerror("invalid xstart: %d\n", xstart);
+      logerror("invalid x: %d\n", xstart);
       return -1;
     }
     xstart = n->x;
@@ -88,11 +96,12 @@ int ncplane_polyfill_yx(ncplane* n, int ystart, int xstart, const nccell* c){
   if(strcmp(fillegc, targ) == 0){
     return 0;
   }
+  int ret = -1;
   // we need an external copy of this, since we'll be writing to it on
-  // the first call into ncplane_polyfill_recurse()
+  // the first call into ncplane_polyfill_inner()
   char* targcopy = strdup(targ);
   if(targcopy){
-    ret = ncplane_polyfill_recurse(n, y, x, c, targcopy);
+    ret = ncplane_polyfill_inner(n, y, x, c, targcopy);
     free(targcopy);
   }
   return ret;
@@ -141,69 +150,6 @@ bool check_gradient_args(uint64_t ul, uint64_t ur, uint64_t bl, uint64_t br){
   return false;
 }
 
-// takes a signed starting coordinate (where -1 indicates the cursor's
-// position), and an unsigned vector (where 0 indicates "everything
-// remaining", i.e. to the right and below). returns 0 iff everything
-// is valid and on the plane, filling in 'ystart'/'xstart' with the
-// (non-negative) starting coordinates and 'ylen'/'xlen with the
-// (positive) dimensions of the affected area.
-static int
-check_geometry_args(const ncplane* n, int y, int x,
-                    unsigned* ylen, unsigned* xlen,
-                    unsigned* ystart, unsigned* xstart){
-  // handle the special -1 case for y/x, and reject other negatives
-  if(y < 0){
-    if(y != -1){
-      logerror("invalid y: %d\n", y);
-      return -1;
-    }
-    y = n->y;
-  }
-  if(x < 0){
-    if(x != -1){
-      logerror("invalid x: %d\n", x);
-      return -1;
-    }
-    x = n->x;
-  }
-  // y and x are both now definitely positive, but might be off-plane.
-  // lock in y and x as ystart and xstart for unsigned comparisons.
-  *ystart = y;
-  *xstart = x;
-  unsigned ymax, xmax;
-  ncplane_dim_yx(n, &ymax, &xmax);
-  if(*ystart >= ymax || *xstart >= xmax){
-    logerror("invalid starting coordinates: %u/%u\n", *ystart, *xstart);
-    return -1;
-  }
-  // handle the special 0 case for ylen/xlen
-  if(*ylen == 0){
-    *ylen = ymax - *ystart;
-  }
-  if(*xlen == 0){
-    *xlen = xmax - *xstart;
-  }
-  // ensure ylen/xlen are on-plane
-  if(*ylen > ymax){
-    logerror("ylen > dimy %u > %u\n", *ylen, ymax);
-    return -1;
-  }
-  if(*xlen > xmax){
-    logerror("xlen > dimx %u > %u\n", *xlen, xmax);
-    return -1;
-  }
-  // ensure x + xlen and y + ylen are on-plane, without overflow
-  if(ymax - *ylen < *ystart){
-    logerror("y + ylen > ymax %u + %u > %u\n", *ystart, *ylen, ymax);
-    return -1;
-  }
-  if(xmax - *xlen < *xstart){
-    logerror("x + xlen > xmax %u + %u > %u\n", *xstart, *xlen, xmax);
-    return -1;
-  }
-  return 0;
-}
-
 // calculate both channels of a gradient at a particular point, knowing that
 // we're using double halfblocks, into `c`->channels.
 static inline void
@@ -248,7 +194,7 @@ int ncplane_gradient2x1(ncplane* n, int y, int x, unsigned ylen, unsigned xlen,
       if(pool_blit_direct(&n->pool, targc, "▀", strlen("▀"), 1) <= 0){
         return -1;
       }
-      calc_highgradient(targc, ul, ur, ll, lr, yy - ystart, xx - xstart, ylen, xlen);
+      calc_highgradient(targc, ul, ur, ll, lr, yy - ystart, xx - xstart, ylen * 2, xlen);
       ++total;
     }
   }
diff --git a/src/lib/internal.h b/src/lib/internal.h
index 2bf17bee5..587360c3b 100644
--- a/src/lib/internal.h
+++ b/src/lib/internal.h
@@ -1448,6 +1448,69 @@ int drop_signals(void* nc);
 int block_signals(sigset_t* old_blocked_signals);
 int unblock_signals(const sigset_t* old_blocked_signals);
 
+// takes a signed starting coordinate (where -1 indicates the cursor's
+// position), and an unsigned vector (where 0 indicates "everything
+// remaining", i.e. to the right and below). returns 0 iff everything
+// is valid and on the plane, filling in 'ystart'/'xstart' with the
+// (non-negative) starting coordinates and 'ylen'/'xlen with the
+// (positive) dimensions of the affected area.
+static inline int
+check_geometry_args(const ncplane* n, int y, int x,
+                    unsigned* ylen, unsigned* xlen,
+                    unsigned* ystart, unsigned* xstart){
+  // handle the special -1 case for y/x, and reject other negatives
+  if(y < 0){
+    if(y != -1){
+      logerror("invalid y: %d\n", y);
+      return -1;
+    }
+    y = n->y;
+  }
+  if(x < 0){
+    if(x != -1){
+      logerror("invalid x: %d\n", x);
+      return -1;
+    }
+    x = n->x;
+  }
+  // y and x are both now definitely positive, but might be off-plane.
+  // lock in y and x as ystart and xstart for unsigned comparisons.
+  *ystart = y;
+  *xstart = x;
+  unsigned ymax, xmax;
+  ncplane_dim_yx(n, &ymax, &xmax);
+  if(*ystart >= ymax || *xstart >= xmax){
+    logerror("invalid starting coordinates: %u/%u\n", *ystart, *xstart);
+    return -1;
+  }
+  // handle the special 0 case for ylen/xlen
+  if(*ylen == 0){
+    *ylen = ymax - *ystart;
+  }
+  if(*xlen == 0){
+    *xlen = xmax - *xstart;
+  }
+  // ensure ylen/xlen are on-plane
+  if(*ylen > ymax){
+    logerror("ylen > dimy %u > %u\n", *ylen, ymax);
+    return -1;
+  }
+  if(*xlen > xmax){
+    logerror("xlen > dimx %u > %u\n", *xlen, xmax);
+    return -1;
+  }
+  // ensure x + xlen and y + ylen are on-plane, without overflow
+  if(ymax - *ylen < *ystart){
+    logerror("y + ylen > ymax %u + %u > %u\n", *ystart, *ylen, ymax);
+    return -1;
+  }
+  if(xmax - *xlen < *xstart){
+    logerror("x + xlen > xmax %u + %u > %u\n", *xstart, *xlen, xmax);
+    return -1;
+  }
+  return 0;
+}
+
 void ncvisual_printbanner(fbuf* f);
 
 // alpha comes to us 0--255, but we have only 3 alpha values to map them to
@@ -1615,6 +1678,27 @@ resize_bitmap(const uint32_t* bmap, int srows, int scols, size_t sstride,
   return ret;
 }
 
+// a neighbor on which to polyfill. by the time we get to it, it might or
+// might not have been filled in. if so, discard immediately. otherwise,
+// check self, and if valid, push all neighbors.
+struct topolyfill {
+  int y, x;
+  struct topolyfill* next;
+};
+
+static inline struct topolyfill*
+create_polyfill_op(int y, int x, struct topolyfill** stck){
+  // cast for the benefit of c++ callers
+  struct topolyfill* n = (struct topolyfill*)malloc(sizeof(*n));
+  if(n){
+    n->y = y;
+    n->x = x;
+    n->next = *stck;
+    *stck = n;
+  }
+  return n;
+}
+
 // implemented by a multimedia backend (ffmpeg or oiio), and installed
 // prior to calling notcurses_core_init() (by notcurses_init()).
 typedef struct ncvisual_implementation {
diff --git a/src/lib/metric.c b/src/lib/metric.c
index 38585e780..9a8e9d8ad 100644
--- a/src/lib/metric.c
+++ b/src/lib/metric.c
@@ -22,8 +22,9 @@ detect_utf8(void){
   }
 }
 
-const char *ncmetric(uintmax_t val, uintmax_t decimal, char *buf, int omitdec,
-                     uintmax_t mult, int uprefix){
+const char* ncnmetric(uintmax_t val, size_t s, uintmax_t decimal,
+                      char* buf, int omitdec, uintmax_t mult,
+                      int uprefix){
   // FIXME this is global to the process...ick :/
   fesetround(FE_TONEAREST);
   pthread_once(&utf8_detector, detect_utf8);
@@ -70,15 +71,17 @@ const char *ncmetric(uintmax_t val, uintmax_t decimal, char *buf, int omitdec,
     // 1,024). That can overflow with large 64-bit values, but we can first
     // divide both sides by mult, and then scale by 100.
     if(omitdec && (val % dv) == 0){
-      sprintfed = sprintf(buf, "%" PRIu64 "%lc", (uint64_t)(val / dv),
+      sprintfed = snprintf(buf, s, "%" PRIu64 "%lc", (uint64_t)(val / dv),
                           (wint_t)prefixes[consumed - 1]);
     }else{
-      sprintfed = sprintf(buf, "%.2f%lc", (double)val / dv,
+      sprintfed = snprintf(buf, s, "%.2f%lc", (double)val / dv,
                           (wint_t)prefixes[consumed - 1]);
     }
     if(uprefix){
-      buf[sprintfed] = uprefix;
-      buf[sprintfed + 1] = '\0';
+      if((size_t)sprintfed < s){
+        buf[sprintfed] = uprefix;
+        buf[++sprintfed] = '\0';
+      }
     }
     return buf;
   }
@@ -86,22 +89,29 @@ const char *ncmetric(uintmax_t val, uintmax_t decimal, char *buf, int omitdec,
   // val / decimal < dv (or we ran out of prefixes)
   if(omitdec && val % decimal == 0){
     if(consumed){
-      sprintfed = sprintf(buf, "%" PRIu64 "%lc", (uint64_t)(val / decimal),
+      sprintfed = snprintf(buf, s, "%" PRIu64 "%lc", (uint64_t)(val / decimal),
                           (wint_t)subprefixes[consumed - 1]);
     }else{
-      sprintfed = sprintf(buf, "%" PRIu64, (uint64_t)(val / decimal));
+      sprintfed = snprintf(buf, s, "%" PRIu64, (uint64_t)(val / decimal));
     }
   }else{
     if(consumed){
-      sprintfed = sprintf(buf, "%.2f%lc", (double)val / decimal,
+      sprintfed = snprintf(buf, s, "%.2f%lc", (double)val / decimal,
                           (wint_t)subprefixes[consumed - 1]);
     }else{
-      sprintfed = sprintf(buf, "%.2f", (double)val / decimal);
+      sprintfed = snprintf(buf, s, "%.2f", (double)val / decimal);
     }
   }
   if(consumed && uprefix){
-    buf[sprintfed] = uprefix;
-    buf[sprintfed + 1] = '\0';
+    if((size_t)sprintfed < s){
+      buf[sprintfed] = uprefix;
+      buf[++sprintfed] = '\0';
+    }
   }
   return buf;
 }
+
+const char *ncmetric(uintmax_t val, uintmax_t decimal, char *buf, int omitdec,
+                     uintmax_t mult, int uprefix){
+  return ncnmetric(val, SIZE_MAX, decimal, buf, omitdec, mult, uprefix);
+}
diff --git a/src/lib/notcurses.c b/src/lib/notcurses.c
index 7e0f4e422..13fa4f926 100644
--- a/src/lib/notcurses.c
+++ b/src/lib/notcurses.c
@@ -1994,6 +1994,7 @@ int ncplane_vline_interp(ncplane* n, const nccell* c, unsigned len,
   return ret;
 }
 
+// we must have at least 2x2, or it's an error
 int ncplane_box(ncplane* n, const nccell* ul, const nccell* ur,
                 const nccell* ll, const nccell* lr, const nccell* hl,
                 const nccell* vl, unsigned ystop, unsigned xstop,
@@ -2845,23 +2846,11 @@ is_bg_p(int idx, int py, int px, int width){
 
 static inline uint32_t*
 ncplane_as_rgba_internal(const ncplane* nc, ncblitter_e blit,
-                         unsigned begy, unsigned begx, unsigned leny,
-                         unsigned lenx, unsigned* pxdimy, unsigned* pxdimx){
+                         int begy, int begx, unsigned leny, unsigned lenx,
+                         unsigned* pxdimy, unsigned* pxdimx){
   const notcurses* ncur = ncplane_notcurses_const(nc);
-  if(begx >= (unsigned)nc->lenx || begy >= (unsigned)nc->leny){
-    logerror("invalid origin (%u,%u)\n", begy, begx);
-    return NULL;
-  }
-  if(lenx == 0){ // -1 means "to the end"; use all space available
-    lenx = nc->lenx - begx;
-  }
-  if(leny == 0){
-    leny = nc->leny - begy;
-  }
-//fprintf(stderr, "sum: %d/%d avail: %d/%d\n", begy + leny, begx + lenx, nc->leny, nc->lenx);
-  if(nc->lenx - begx < lenx || nc->leny - begy < leny){
-    logerror("invalid specs %u + %u > %d or %u + %u > %d\n",
-             begx, lenx, nc->lenx, begy, leny, nc->leny);
+  unsigned ystart, xstart;
+  if(check_geometry_args(nc, begy, begx, &leny, &lenx, &ystart, &xstart)){
     return NULL;
   }
   if(blit == NCBLIT_PIXEL){ // FIXME extend this to support sprixels
@@ -2887,8 +2876,8 @@ ncplane_as_rgba_internal(const ncplane* nc, ncblitter_e blit,
   uint32_t* ret = malloc(sizeof(*ret) * lenx * bset->width * leny * bset->height);
 //fprintf(stderr, "GEOM: %d/%d %d/%d ret: %p\n", bset->height, bset->width, *pxdimy, *pxdimx, ret);
   if(ret){
-    for(unsigned y = begy, targy = 0 ; y < begy + leny ; ++y, targy += bset->height){
-      for(unsigned x = begx, targx = 0 ; x < begx + lenx ; ++x, targx += bset->width){
+    for(unsigned y = ystart, targy = 0 ; y < ystart + leny ; ++y, targy += bset->height){
+      for(unsigned x = xstart, targx = 0 ; x < xstart + lenx ; ++x, targx += bset->width){
         uint16_t stylemask;
         uint64_t channels;
         char* c = ncplane_at_yx(nc, y, x, &stylemask, &channels);
@@ -2941,7 +2930,7 @@ ncplane_as_rgba_internal(const ncplane* nc, ncblitter_e blit,
 }
 
 uint32_t* ncplane_as_rgba(const ncplane* nc, ncblitter_e blit,
-                          unsigned begy, unsigned begx, unsigned leny,
+                          int begy, int begx, unsigned leny,
                           unsigned lenx, unsigned* pxdimy, unsigned* pxdimx){
   unsigned px, py;
   if(!pxdimy){
@@ -2955,39 +2944,15 @@ uint32_t* ncplane_as_rgba(const ncplane* nc, ncblitter_e blit,
 
 // return a heap-allocated copy of the contents
 char* ncplane_contents(ncplane* nc, int begy, int begx, unsigned leny, unsigned lenx){
-  if(begy < 0){
-    if(begy != -1){
-      logerror("invalid y coordinate: %d\n", begy);
-    }
-    begy = nc->y;
-  }
-  if(begx < 0){
-    if(begx != -1){
-      logerror("invalid x coordinate: %d\n", begx);
-    }
-    begx = nc->x;
-  }
-  if((unsigned)begx >= nc->lenx || (unsigned)begy >= nc->leny){
-    logerror("beginning coordinates (%d/%d) exceeded area (%u/%u)\n",
-             begy, begx, nc->leny, nc->lenx);
-    return NULL;
-  }
-  if(lenx == 0){ // 0 means "to the end"; use all space available
-    lenx = nc->lenx - begx;
-  }
-  if(leny == 0){
-    leny = nc->leny - begy;
-  }
-  if(nc->lenx - begx < lenx || nc->leny - begy < leny){
-    logerror("ending coordinates (%u/%u) exceeded lengths (%u/%u)\n",
-             begy + leny, begx + lenx, nc->leny, nc->lenx);
+  unsigned ystart, xstart;
+  if(check_geometry_args(nc, begy, begx, &leny, &lenx, &ystart, &xstart)){
     return NULL;
   }
   size_t retlen = 1;
   char* ret = malloc(retlen);
   if(ret){
-    for(unsigned y = begy, targy = 0 ; y < begy + leny ; ++y, targy += 2){
-      for(unsigned x = begx, targx = 0 ; x < begx + lenx ; ++x, ++targx){
+    for(unsigned y = ystart, targy = 0 ; y < ystart + leny ; ++y, targy += 2){
+      for(unsigned x = xstart, targx = 0 ; x < xstart + lenx ; ++x, ++targx){
         nccell ncl = CELL_TRIVIAL_INITIALIZER;
         // we need ncplane_at_yx_cell() here instead of ncplane_at_yx(),
         // because we should only have one copy of each wide EGC.
diff --git a/src/lib/reader.c b/src/lib/reader.c
index cda56647f..3b1e2416f 100644
--- a/src/lib/reader.c
+++ b/src/lib/reader.c
@@ -61,10 +61,10 @@ ncreader_redraw(ncreader* n){
   assert(n->xproject >= 0);
   assert(n->textarea->lenx >= n->ncp->lenx);
   assert(n->textarea->leny >= n->ncp->leny);
-  for(int y = 0 ; y < n->ncp->leny ; ++y){
-    const int texty = y;
-    for(int x = 0 ; x < n->ncp->lenx ; ++x){
-      const int textx = x + n->xproject;
+  for(unsigned y = 0 ; y < n->ncp->leny ; ++y){
+    const unsigned texty = y;
+    for(unsigned x = 0 ; x < n->ncp->lenx ; ++x){
+      const unsigned textx = x + n->xproject;
       const nccell* src = &n->textarea->fb[nfbcellidx(n->textarea, texty, textx)];
       nccell* dst = &n->ncp->fb[nfbcellidx(n->ncp, y, x)];
 //fprintf(stderr, "projecting %d/%d [%s] to %d/%d [%s]\n", texty, textx, cell_extended_gcluster(n->textarea, src), y, x, cell_extended_gcluster(n->ncp, dst));
@@ -121,9 +121,9 @@ int ncreader_move_left(ncreader* n){
 // row. if on the right side of the viewarea, but not the right side of the
 // textarea, pans right. returns 0 if a move was made.
 int ncreader_move_right(ncreader* n){
-  int viewx = n->ncp->x;
-  int textx = n->textarea->x;
-  int y = n->ncp->y;
+  unsigned textx = n->textarea->x;
+  unsigned y = n->ncp->y;
+  unsigned viewx = n->ncp->x;
 //fprintf(stderr, "moving right: tcurs: %dx%d vcurs: %dx%d xproj: %d\n", y, textx, y, viewx, n->xproject);
   if(textx >= n->textarea->lenx - 1){
     // are we on the last column of the textarea? if so, we must also be on
@@ -171,7 +171,7 @@ int ncreader_move_up(ncreader* n){
 // try to move down. does not move past the bottom of the textarea.
 // returns 0 if a move was made.
 int ncreader_move_down(ncreader* n){
-  int y = n->ncp->y;
+  unsigned y = n->ncp->y;
   if(y >= n->textarea->leny - 1){
     // are we on the last row of the textarea? if so, we can't move.
     return -1;
@@ -190,14 +190,14 @@ int ncreader_write_egc(ncreader* n, const char* egc){
     logerror("Fed illegal UTF-8 [%s]\n", egc);
     return -1;
   }
-  if(n->textarea->x >= n->textarea->lenx - cols){
+  if(n->textarea->x >= (int)n->textarea->lenx - cols){
     if(n->horscroll){
       if(ncplane_resize_simple(n->textarea, n->textarea->leny, n->textarea->lenx + cols)){
         return -1;
       }
       ++n->xproject;
     }
-  }else if(n->ncp->x >= n->ncp->lenx){
+  }else if((unsigned)n->ncp->x >= n->ncp->lenx){
     ++n->xproject;
   }
   // use ncplane_putegc on both planes because it'll get cursor movement right
@@ -207,12 +207,12 @@ int ncreader_write_egc(ncreader* n, const char* egc){
   if(ncplane_putegc(n->ncp, egc, NULL) < 0){
     return -1;
   }
-  if(n->textarea->x >= n->textarea->lenx - cols){
+  if(n->textarea->x >= (int)n->textarea->lenx - cols){
     if(!n->horscroll){
       n->textarea->x = n->textarea->lenx - cols;
     }
   }
-  if(n->ncp->x >= n->ncp->lenx - cols){
+  if(n->ncp->x >= (int)n->ncp->lenx - cols){
     n->ncp->x = n->ncp->lenx - cols;
   }
   ncreader_redraw(n);
@@ -275,7 +275,7 @@ ncreader_ctrl_input(ncreader* n, const ncinput* ni){
       }
       break;
     case 'E': // cursor to end of line
-      while(n->textarea->x < ncplane_dim_x(n->textarea) - 1){
+      while(n->textarea->x < (int)ncplane_dim_x(n->textarea) - 1){
         if(ncreader_move_right(n)){
           break;
         }
@@ -320,7 +320,7 @@ ncreader_alt_input(ncreader* n, const ncinput* ni){
       }
       break;
     case 'f': // forward one word (past end cell)
-      while(n->textarea->x < ncplane_dim_x(n->textarea) - 1){
+      while(n->textarea->x < (int)ncplane_dim_x(n->textarea) - 1){
         if(ncreader_move_right(n)){
           break;
         }
diff --git a/src/lib/reel.c b/src/lib/reel.c
index 2b40a1a3f..a4ab71cdd 100644
--- a/src/lib/reel.c
+++ b/src/lib/reel.c
@@ -186,7 +186,10 @@ tablet_geom(const ncreel* nr, nctablet* t, int* begx, int* begy,
 //fprintf(stderr, "jigsawing %p with %d/%d dir %d\n", t, frontiertop, frontierbottom, direction);
   *begy = 0;
   *begx = 0;
-  ncplane_dim_yx(nr->p, leny, lenx);
+  unsigned uleny, ulenx;
+  ncplane_dim_yx(nr->p, &uleny, &ulenx);
+  *leny = uleny;
+  *lenx = ulenx;
   if(frontiertop < 0){
     if(direction == DIRECTION_UP){
       return -1;
@@ -501,14 +504,15 @@ tighten_reel_down(ncreel* r, int ybot){
     if(cur->p == NULL){
       break;
     }
-    int cury, curx, ylen;
+    int cury, curx;
+    unsigned ylen;
     ncplane_yx(cur->p, &cury, &curx);
     ncplane_dim_yx(cur->p, &ylen, NULL);
-    if(cury <= ybot - ylen - 1){
+    if(cury <= ybot - (int)ylen - 1){
       break;
     }
 //fprintf(stderr, "tightening %p down to %d from %d\n", cur, ybot - ylen, cury);
-    cury = ybot - ylen;
+    cury = ybot - (int)ylen;
     ncplane_move_yx(cur->p, cury, curx);
     ybot = cury - 1;
     if((cur = cur->prev) == r->tablets){
@@ -580,7 +584,7 @@ tighten_reel(ncreel* r){
     const int ybot = rylen - 1 + !!(r->ropts.bordermask & NCBOXMASK_BOTTOM);
     // FIXME want to tighten down whenever we're at the bottom, and the reel
     // is full, not just in this case (this can leave a gap of more than 1 row)
-    if(yoff + ylen + 1 >= ybot){
+    if(yoff + (int)ylen + 1 >= ybot){
       if(tighten_reel_down(r, ybot)){
         return -1;
       }
diff --git a/src/lib/selector.c b/src/lib/selector.c
index 8eaf5227b..b52975228 100644
--- a/src/lib/selector.c
+++ b/src/lib/selector.c
@@ -19,16 +19,16 @@ typedef struct ncselector {
   unsigned selected;             // index of selection
   unsigned startdisp;            // index of first option displayed
   unsigned maxdisplay;           // max number of items to display, 0 -> no limit
-  int longop;                    // columns occupied by longest option
-  int longdesc;                  // columns occupied by longest description
+  unsigned longop;               // columns occupied by longest option
+  unsigned longdesc;             // columns occupied by longest description
   struct ncselector_int* items;  // list of items and descriptions, heap-copied
   unsigned itemcount;            // number of pairs in 'items'
   char* title;                   // can be NULL, in which case there's no riser
-  int titlecols;                 // columns occupied by title
+  unsigned titlecols;            // columns occupied by title
   char* secondary;               // can be NULL
-  int secondarycols;             // columns occupied by secondary
+  unsigned secondarycols;        // columns occupied by secondary
   char* footer;                  // can be NULL
-  int footercols;                // columns occupied by footer
+  unsigned footercols;           // columns occupied by footer
   uint64_t opchannels;           // option channels
   uint64_t descchannels;         // description channels
   uint64_t titlechannels;        // title channels
@@ -42,15 +42,15 @@ typedef struct ncmultiselector {
   unsigned current;               // index of highlighted item
   unsigned startdisp;             // index of first option displayed
   unsigned maxdisplay;            // max number of items to display, 0 -> no limit
-  int longitem;                   // columns occupied by longest item
+  unsigned longitem;              // columns occupied by longest item
   struct ncmselector_int* items;  // items, descriptions, and statuses, heap-copied
   unsigned itemcount;             // number of pairs in 'items'
   char* title;                    // can be NULL, in which case there's no riser
   unsigned titlecols;             // columns occupied by title
   char* secondary;                // can be NULL
-  int secondarycols;              // columns occupied by secondary
+  unsigned secondarycols;         // columns occupied by secondary
   char* footer;                   // can be NULL
-  int footercols;                 // columns occupied by footer
+  unsigned footercols;            // columns occupied by footer
   uint64_t opchannels;            // option channels
   uint64_t descchannels;          // description channels
   uint64_t titlechannels;         // title channels
@@ -62,7 +62,7 @@ typedef struct ncmultiselector {
 // ideal body width given the ncselector's items and secondary/footer
 static int
 ncselector_body_width(const ncselector* n){
-  int cols = 0;
+  unsigned cols = 0;
   // the body is the maximum of
   //  * longop + longdesc + 5
   //  * secondary + 2
@@ -162,7 +162,7 @@ ncselector_draw(ncselector* n){
   // Top line of body (background and possibly up arrow)
   ++yoff;
   ncplane_cursor_move_yx(n->ncp, yoff, xoff + 1);
-  for(int i = xoff + 1 ; i < dimx - 1 ; ++i){
+  for(unsigned i = xoff + 1 ; i < dimx - 1 ; ++i){
     nccell transc = CELL_TRIVIAL_INITIALIZER; // fall back to base cell
     ncplane_putc(n->ncp, &transc);
   }
@@ -181,12 +181,12 @@ ncselector_draw(ncselector* n){
   n->uarrowy = yoff;
   unsigned printidx = n->startdisp;
   unsigned printed = 0;
-  for(yoff += 1 ; yoff < dimy - 2 ; ++yoff){
+  for(yoff += 1 ; yoff < (int)dimy - 2 ; ++yoff){
     if(n->maxdisplay && printed == n->maxdisplay){
       break;
     }
     ncplane_cursor_move_yx(n->ncp, yoff, xoff + 1);
-    for(int i = xoff + 1 ; i < dimx - 1 ; ++i){
+    for(int i = xoff + 1 ; i < (int)dimx - 1 ; ++i){
       nccell transc = CELL_TRIVIAL_INITIALIZER; // fall back to base cell
       ncplane_putc(n->ncp, &transc);
     }
@@ -207,7 +207,7 @@ ncselector_draw(ncselector* n){
   }
   // Bottom line of body (background and possibly down arrow)
   ncplane_cursor_move_yx(n->ncp, yoff, xoff + 1);
-  for(int i = xoff + 1 ; i < dimx - 1 ; ++i){
+  for(int i = xoff + 1 ; i < (int)dimx - 1 ; ++i){
     nccell transc = CELL_TRIVIAL_INITIALIZER; // fall back to base cell
     ncplane_putc(n->ncp, &transc);
   }
@@ -225,8 +225,8 @@ ncselector_draw(ncselector* n){
 
 // calculate the necessary dimensions based off properties of the selector
 static void
-ncselector_dim_yx(const ncselector* n, int* ncdimy, int* ncdimx){
-  int rows = 0, cols = 0; // desired dimensions
+ncselector_dim_yx(const ncselector* n, unsigned* ncdimy, unsigned* ncdimx){
+  unsigned rows = 0, cols = 0; // desired dimensions
   const ncplane* parent = ncplane_parent(n->ncp);
   unsigned dimy, dimx; // dimensions of containing plane
   ncplane_dim_yx(parent, &dimy, &dimx);
@@ -305,13 +305,21 @@ ncselector* ncselector_create(ncplane* n, const ncselector_options* opts){
   }
   for(ns->itemcount = 0 ; ns->itemcount < itemcount ; ++ns->itemcount){
     const struct ncselector_item* src = &opts->items[ns->itemcount];
-    int cols = ncstrwidth(src->option);
+    int unsafe = ncstrwidth(src->option);
+    if(unsafe < 0){
+      goto freeitems;
+    }
+    unsigned cols = unsafe;
     ns->items[ns->itemcount].opcolumns = cols;
     if(cols > ns->longop){
       ns->longop = cols;
     }
     const char *desc = src->desc ? src->desc : "";
-    cols = ncstrwidth(desc);
+    unsafe = ncstrwidth(desc);
+    if(unsafe < 0){
+      goto freeitems;
+    }
+    cols = unsafe;
     ns->items[ns->itemcount].desccolumns = cols;
     if(cols > ns->longdesc){
       ns->longdesc = cols;
@@ -324,7 +332,7 @@ ncselector* ncselector_create(ncplane* n, const ncselector_options* opts){
       goto freeitems;
     }
   }
-  int dimy, dimx;
+  unsigned dimy, dimx;
   ns->ncp = n;
   ncselector_dim_yx(ns, &dimy, &dimx);
   if(ncplane_resize_simple(n, dimy, dimx)){
@@ -347,7 +355,7 @@ freeitems:
 }
 
 int ncselector_additem(ncselector* n, const struct ncselector_item* item){
-  int origdimy, origdimx;
+  unsigned origdimy, origdimx;
   ncselector_dim_yx(n, &origdimy, &origdimx);
   size_t newsize = sizeof(*n->items) * (n->itemcount + 1);
   struct ncselector_int* items = realloc(n->items, newsize);
@@ -358,7 +366,11 @@ int ncselector_additem(ncselector* n, const struct ncselector_item* item){
   n->items[n->itemcount].option = strdup(item->option);
   const char *desc = item->desc ? item->desc : "";
   n->items[n->itemcount].desc = strdup(desc);
-  int cols = ncstrwidth(item->option);
+  int usafecols = ncstrwidth(item->option);
+  if(usafecols < 0){
+    return -1;
+  }
+  unsigned cols = usafecols;
   n->items[n->itemcount].opcolumns = cols;
   if(cols > n->longop){
     n->longop = cols;
@@ -369,7 +381,7 @@ int ncselector_additem(ncselector* n, const struct ncselector_item* item){
     n->longdesc = cols;
   }
   ++n->itemcount;
-  int dimy, dimx;
+  unsigned dimy, dimx;
   ncselector_dim_yx(n, &dimy, &dimx);
   if(origdimx < dimx || origdimy < dimy){ // resize if too small
     ncplane_resize_simple(n->ncp, dimy, dimx);
@@ -378,7 +390,7 @@ int ncselector_additem(ncselector* n, const struct ncselector_item* item){
 }
 
 int ncselector_delitem(ncselector* n, const char* item){
-  int origdimy, origdimx;
+  unsigned origdimy, origdimx;
   ncselector_dim_yx(n, &origdimy, &origdimx);
   bool found = false;
   int maxop = 0, maxdesc = 0;
@@ -410,7 +422,7 @@ int ncselector_delitem(ncselector* n, const char* item){
   if(found){
     n->longop = maxop;
     n->longdesc = maxdesc;
-    int dimy, dimx;
+    unsigned dimy, dimx;
     ncselector_dim_yx(n, &dimy, &dimx);
     if(origdimx > dimx || origdimy > dimy){ // resize if too big
       ncplane_resize_simple(n->ncp, dimy, dimx);
@@ -560,9 +572,9 @@ ncplane* ncmultiselector_plane(ncmultiselector* n){
 }
 
 // ideal body width given the ncselector's items and secondary/footer
-static int
+static unsigned
 ncmultiselector_body_width(const ncmultiselector* n){
-  int cols = 0;
+  unsigned cols = 0;
   // the body is the maximum of
   //  * longop + longdesc + 5
   //  * secondary + 2
@@ -589,7 +601,7 @@ ncmultiselector_draw(ncmultiselector* n){
   // if we have a title, we'll draw a riser. the riser is two rows tall, and
   // exactly four columns longer than the title, and aligned to the right. we
   // draw a rounded box. the body will blow part or all of the bottom away.
-  int yoff = 0;
+  unsigned yoff = 0;
   if(n->title){
     size_t riserwidth = n->titlecols + 4;
     int offx = ncplane_halign(n->ncp, NCALIGN_RIGHT, riserwidth);
@@ -649,7 +661,7 @@ ncmultiselector_draw(ncmultiselector* n){
   // Top line of body (background and possibly up arrow)
   ++yoff;
   ncplane_cursor_move_yx(n->ncp, yoff, xoff + 1);
-  for(int i = xoff + 1 ; i < dimx - 1 ; ++i){
+  for(unsigned i = xoff + 1 ; i < dimx - 1 ; ++i){
     nccell transc = CELL_TRIVIAL_INITIALIZER; // fall back to base cell
     ncplane_putc(n->ncp, &transc);
   }
@@ -670,7 +682,7 @@ ncmultiselector_draw(ncmultiselector* n){
       break;
     }
     ncplane_cursor_move_yx(n->ncp, yoff, xoff + 1);
-    for(int i = xoff + 1 ; i < dimx - 1 ; ++i){
+    for(unsigned i = xoff + 1 ; i < dimx - 1 ; ++i){
       nccell transc = CELL_TRIVIAL_INITIALIZER; // fall back to base cell
       ncplane_putc(n->ncp, &transc);
     }
@@ -700,7 +712,7 @@ ncmultiselector_draw(ncmultiselector* n){
   }
   // Bottom line of body (background and possibly down arrow)
   ncplane_cursor_move_yx(n->ncp, yoff, xoff + 1);
-  for(int i = xoff + 1 ; i < dimx - 1 ; ++i){
+  for(unsigned i = xoff + 1 ; i < dimx - 1 ; ++i){
     nccell transc = CELL_TRIVIAL_INITIALIZER; // fall back to base cell
     ncplane_putc(n->ncp, &transc);
   }
@@ -899,11 +911,19 @@ ncmultiselector* ncmultiselector_create(ncplane* n, const ncmultiselector_option
   }
   for(ns->itemcount = 0 ; ns->itemcount < itemcount ; ++ns->itemcount){
     const struct ncmselector_item* src = &opts->items[ns->itemcount];
-    int cols = ncstrwidth(src->option);
+    int unsafe = ncstrwidth(src->option);
+    if(unsafe < 0){
+      goto freeitems;
+    }
+    unsigned cols = unsafe;
     if(cols > ns->longitem){
       ns->longitem = cols;
     }
-    int cols2 = ncstrwidth(src->desc);
+    unsafe = ncstrwidth(src->desc);
+    if(unsafe < 0){
+      goto freeitems;
+    }
+    unsigned cols2 = unsafe;
     if(cols + cols2 > ns->longitem){
       ns->longitem = cols + cols2;
     }
diff --git a/src/lib/visual.c b/src/lib/visual.c
index 0e5db8a0d..28f2544fe 100644
--- a/src/lib/visual.c
+++ b/src/lib/visual.c
@@ -1193,7 +1193,7 @@ ncplane* ncvisual_render(notcurses* nc, ncvisual* ncv, const struct ncvisual_opt
 }
 
 ncvisual* ncvisual_from_plane(const ncplane* n, ncblitter_e blit,
-                              unsigned begy, unsigned begx,
+                              int begy, int begx,
                               unsigned leny, unsigned lenx){
   unsigned py, px;
   uint32_t* rgba = ncplane_as_rgba(n, blit, begy, begx, leny, lenx, &py, &px);
@@ -1269,26 +1269,6 @@ int ncvisual_at_yx(const ncvisual* n, unsigned y, unsigned x, uint32_t* pixel){
   return 0;
 }
 
-// a neighbor on which to polyfill. by the time we get to it, it might or
-// might not have been filled in. if so, discard immediately. otherwise,
-// check self, and if valid, push all neighbors.
-struct topolyfill {
-  int y, x;
-  struct topolyfill* next;
-};
-
-static inline struct topolyfill*
-create_polyfill_op(int y, int x, struct topolyfill** stack){
-  struct topolyfill* n = malloc(sizeof(*n));
-  if(n){
-    n->y = y;
-    n->x = x;
-    n->next = *stack;
-    *stack = n;
-  }
-  return n;
-}
-
 // originally i wrote this recursively, at which point it promptly began
 // exploding once i multithreaded the [yield] demo. hence the clumsy stack
 // and hand-rolled iteration. alas, poor yorick!
@@ -1314,6 +1294,7 @@ ncvisual_polyfill_core(ncvisual* n, unsigned y, unsigned x, uint32_t rgba, uint3
       *pixel = rgba;
       if(y){
         if(create_polyfill_op(y - 1, x, &stack) == NULL){
+          // FIXME need free stack!
           return -1;
         }
       }
diff --git a/src/poc/ncwidth.c b/src/poc/ncwidth.c
index e90249fe3..fa665d363 100644
--- a/src/poc/ncwidth.c
+++ b/src/poc/ncwidth.c
@@ -74,13 +74,14 @@ int main(int argc, char **argv){
       totalb += conv;
       add_wchar(&wbuf, &bufsize, &used, w);
     }
-    int y, x, newy, newx;
     putchar('\n');
+    unsigned y, x;
     ncdirect_cursor_yx(n, &y, &x);
     printf("%s", *argv);
     fflush(stdout);
+    unsigned newy, newx;
     ncdirect_cursor_yx(n, &newy, &newx);
-    int realcols = (newx - x) + ncdirect_dim_x(n) * (newy - y);
+    unsigned realcols = (newx - x) + ncdirect_dim_x(n) * (newy - y);
     printf("\n iterated wcwidth: %d total bytes: %llu wcswidth: %d true width: %d\n\n",
            totalcols, (unsigned long long)totalb, wcswidth(wbuf, used), realcols);
     ncdirect_cursor_yx(n, &y, &x);
@@ -123,7 +124,7 @@ int main(int argc, char **argv){
     }
     ncdirect_set_fg_default(n);
     ncdirect_set_bg_default(n);
-    for(int z = 0 ; z < realcols && z < ncdirect_dim_x(n) ; ++z){
+    for(unsigned z = 0 ; z < realcols && z < ncdirect_dim_x(n) ; ++z){
       putchar('0' + z % 10);
     }
     if(realcols < ncdirect_dim_x(n)){
diff --git a/src/poc/rtl.c b/src/poc/rtl.c
index 3f09d9a88..a702d063d 100644
--- a/src/poc/rtl.c
+++ b/src/poc/rtl.c
@@ -10,7 +10,7 @@ int main(void){
   if(!nc){
     return EXIT_FAILURE;
   }
-  int dimy, dimx;
+  unsigned dimy, dimx;
   struct ncplane* n = notcurses_stddim_yx(nc, &dimy, &dimx);
   ncplane_printf_yx(n, dimy / 2 - 2, 0, "ࡢ‎ࡣ‎ࡤ‎ࡥ‎ࡦ‎ࡧ‎ࡨ‎ࡩ‎ࡪ‎ࢠ‎ࢡ‎ࢢ‎ࢣ‎ࢤ‎ࢥ‎ࢦ‎ࢧ‎ࢨ‎ࢩ‎ࢪ‎ࢫ‎ࢬ‎ࢭ‎ࢮ‎ࢯ‎ࢰ‎ࢱ‎ࢲ‎ࢳ‎ࢴ‎ࢶ‎ࢷ‎ࢸ‎ࢹ‎ࢺ‎ࢻ‎ࢼ‎ࢽ‎࣢ः");
   ncplane_printf_yx(n, dimy / 2 - 1, 0, "࠲‎࠳‎࠴‎࠵‎࠶‎࠷‎࠸‎࠹‎࠺‎࠻‎࠼‎࠽‎࠾‎ࡀ‎ࡁ‎ࡂ‎ࡃ‎ࡄ‎ࡅ‎ࡆ‎ࡇ‎ࡈ‎ࡉ‎ࡊ‎ࡋ‎ࡌ‎ࡍ‎ࡎ‎ࡏ‎ࡐ‎ࡑ‎ࡒ‎ࡓ‎ࡔ‎ࡕ‎ࡖ‎ࡗ‎ࡘ‎࡞‎ࡡ");
diff --git a/src/poc/statepixel.c b/src/poc/statepixel.c
index 9d71efdf8..35150e292 100644
--- a/src/poc/statepixel.c
+++ b/src/poc/statepixel.c
@@ -7,7 +7,7 @@
 static int
 across_row(struct notcurses* nc, int y, struct ncplane* n, struct ncplane* t,
            const struct timespec* ds){
-  for(int x = 0 ; x < ncplane_dim_x(n) ; ++x){
+  for(unsigned x = 0 ; x < ncplane_dim_x(n) ; ++x){
     if(ncplane_move_yx(t, y, x)){
       return -1;
     }
@@ -21,7 +21,7 @@ across_row(struct notcurses* nc, int y, struct ncplane* n, struct ncplane* t,
 
 static int
 across_bmap(struct notcurses* nc, struct ncplane* n, struct ncplane* t, const struct timespec* ds){
-  for(int y = 0 ; y < ncplane_dim_y(n) - 1 ; ++y){
+  for(unsigned y = 0 ; y < ncplane_dim_y(n) - 1 ; ++y){
     if(across_row(nc, y, n, t, ds)){
       return -1;
     }
diff --git a/src/tests/fills.cpp b/src/tests/fills.cpp
index d42844fd5..c6b2fc87f 100644
--- a/src/tests/fills.cpp
+++ b/src/tests/fills.cpp
@@ -577,7 +577,9 @@ TEST_CASE("Fills") {
     const char* qr = "a very simple qr code";
     unsigned dimy, dimx;
     ncplane_dim_yx(n_, &dimy, &dimx);
-    CHECK(0 < ncplane_qrcode(n_, &dimy, &dimx, qr, strlen(qr)));
+    int sdimy = dimy;
+    int sdimx = dimx;
+    CHECK(0 < ncplane_qrcode(n_, &sdimy, &sdimx, qr, strlen(qr)));
     CHECK(0 == notcurses_render(nc_));
   }
 #endif