add ncplane_putwc_stainable, ncplane_putwstr_stainable #985

include/notcurses/notcurses.h

@@ -1458,6 +1458,8 @@ ncplane_putwstr_aligned(struct ncplane* n, int y, ncalign_e align,
   return ncplane_putwstr_yx(n, y, xpos, gclustarr);
 }
 
+API int ncplane_putwstr_stainable(struct ncplane* n, const wchar_t* gclustarr);
+
 static inline int
 ncplane_putwstr(struct ncplane* n, const wchar_t* gclustarr){
   return ncplane_putwstr_yx(n, -1, -1, gclustarr);
@@ -1472,12 +1474,20 @@ ncplane_putwc_yx(struct ncplane* n, int y, int x, wchar_t w){
   return ncplane_putwstr_yx(n, y, x, warr);
 }
 
-// Call ncplane_putwc() at the current cursor position.
+// Write 'w' at the current cursor position, using the plane's current styling.
 static inline int
 ncplane_putwc(struct ncplane* n, wchar_t w){
   return ncplane_putwc_yx(n, -1, -1, w);
 }
 
+// Write 'w' at the current cursor position, using any preexisting styling
+// at that cell.
+static inline int
+ncplane_putwc_stainable(struct ncplane* n, wchar_t w){
+  wchar_t warr[2] = { w, L'\0' };
+  return ncplane_putwstr_stainable(n, warr);
+}
+
 // The ncplane equivalents of printf(3) and vprintf(3).
 API int ncplane_vprintf_aligned(struct ncplane* n, int y, ncalign_e align,
                                 const char* format, va_list ap);

src/lib/notcurses.c

@@ -2318,6 +2318,23 @@ int ncplane_putstr_stainable(struct ncplane* n, const char* gclusters){
   return ret;
 }
 
+int ncplane_putwstr_stainable(ncplane* n, const wchar_t* gclustarr){
+  // maximum of six UTF8-encoded bytes per wchar_t
+  const size_t mbytes = (wcslen(gclustarr) * WCHAR_MAX_UTF8BYTES) + 1;
+  char* mbstr = malloc(mbytes); // need cast for c++ callers
+  if(mbstr == NULL){
+    return -1;
+  }
+  size_t s = wcstombs(mbstr, gclustarr, mbytes);
+  if(s == (size_t)-1){
+    free(mbstr);
+    return -1;
+  }
+  int r = ncplane_putstr_stainable(n, mbstr);
+  free(mbstr);
+  return r;
+}
+
 int ncplane_putnstr_aligned(struct ncplane* n, int y, ncalign_e align, size_t s, const char* str){
   char* chopped = strndup(str, s);
   int ret = ncplane_putstr_aligned(n, y, align, chopped);

tests/wide.cpp

@@ -953,6 +953,40 @@ TEST_CASE("Wide") {
     CHECK(0 == notcurses_render(nc_));
   }
 
+  SUBCASE("Putwc") {
+    wchar_t w = L'\u2658';
+    CHECK(0 == ncplane_set_fg(n_, 0xff00ff));
+    CHECK(0 < ncplane_putwc(n_, w));
+    CHECK(0 == ncplane_set_fg(n_, 0x00ff00));
+    CHECK(0 == notcurses_render(nc_));
+    uint16_t stylemask;
+    uint64_t channels;
+    char* egc = notcurses_at_yx(nc_, 0, 0, &stylemask, &channels);
+    REQUIRE(egc);
+    CHECK(0 == stylemask);
+    CHECK(0xff00ff == channels_fg(channels));
+    CHECK(0 == strcmp("\u2658", egc));
+    free(egc);
+  }
+
+  SUBCASE("PutwcStainable") {
+    wchar_t w = L'\u2658';
+    CHECK(0 == ncplane_set_fg(n_, 0xff00ff));
+    CHECK(0 < ncplane_putwc(n_, w));
+    CHECK(0 == ncplane_set_fg(n_, 0x00ff00));
+    ncplane_home(n_);
+    CHECK(0 < ncplane_putwc_stainable(n_, w));
+    CHECK(0 == notcurses_render(nc_));
+    uint16_t stylemask;
+    uint64_t channels;
+    char* egc = notcurses_at_yx(nc_, 0, 0, &stylemask, &channels);
+    REQUIRE(egc);
+    CHECK(0 == stylemask);
+    CHECK(0xff00ff == channels_fg(channels));
+    CHECK(0 == strcmp("\u2658", egc));
+    free(egc);
+  }
+
   CHECK(0 == notcurses_stop(nc_));
 
 }