No glyph emission on sprixelated planes

Guard against attempts to output glyphs to a sprixelated
plane in ncplane_putc_yx(), the lowest-level common end
of all ncplane_put*() functions. Add unit test #1572.

src/lib/notcurses.c

@@ -1454,19 +1454,24 @@ int cell_load(ncplane* n, nccell* c, const char* gcluster){
 static inline int
 ncplane_put(ncplane* n, int y, int x, const char* egc, int cols,
             uint16_t stylemask, uint64_t channels, int bytes){
+  const notcurses* nc = ncplane_notcurses_const(n);
+  if(n->sprite){
+    logerror(nc, "Can't write glyphs (%s) to sprixelated plane\n", egc);
+    return -1;
+  }
   // FIXME reject any control or space characters here--should be iswgraph()
   // check *before ncplane_cursor_move_yx()* whether we're past the end of the
   // line. if scrolling is enabled, move to the next line if so. if x or y are
   // specified, we must always try to print at exactly that location.
   if(x != -1){
     if(x + cols > n->lenx){
-      logerror(ncplane_notcurses(n), "Target x %d + %d cols >= length %d\n", x, cols, n->lenx);
+      logerror(nc, "Target x %d + %d cols >= length %d\n", x, cols, n->lenx);
       ncplane_cursor_move_yx(n, y, x); // update cursor, though
       return -1;
     }
   }else if(y == -1 && n->x + cols > n->lenx){
     if(!n->scrolling){
-      logerror(ncplane_notcurses(n), "No room to output [%.*s] %d/%d\n", bytes, egc, n->y, n->x);
+      logerror(nc, "No room to output [%.*s] %d/%d\n", bytes, egc, n->y, n->x);
       return -1;
     }
     scroll_down(n);

src/tests/bitmap.cpp

@@ -47,8 +47,38 @@ TEST_CASE("Bitmaps") {
   }
 
   // a sprixel requires a plane large enough to hold it
-  SUBCASE("SprixelTooBig") {
+  SUBCASE("SprixelTooTall") {
     auto y = nc_->tcache.cellpixy + 1;
+    auto x = nc_->tcache.cellpixx;
+    std::vector<uint32_t> v(x * y, htole(0xe61c28ff));
+    auto ncv = ncvisual_from_rgba(v.data(), y, sizeof(decltype(v)::value_type) * x, x);
+    REQUIRE(nullptr != ncv);
+    struct ncplane_options nopts = {
+      .y = 0, .x = 0,
+      .rows = 1, .cols = 1,
+      .userptr = nullptr, .name = "small", .resizecb = nullptr,
+      .flags = 0, .margin_b = 0, .margin_r = 0,
+    };
+    auto n = ncplane_create(n_, &nopts);
+    struct ncvisual_options vopts = {
+      .n = n,
+      .scaling = NCSCALE_NONE,
+      .y = 0,
+      .x = 0,
+      .begy = 0, .begx = 0,
+      .leny = 0, .lenx = 0,
+      .blitter = NCBLIT_PIXEL,
+      .flags = NCVISUAL_OPTION_NODEGRADE,
+      .transcolor = 0,
+    };
+    CHECK(nullptr == ncvisual_render(nc_, ncv, &vopts));
+    CHECK(0 == notcurses_render(nc_));
+    ncvisual_destroy(ncv);
+    CHECK(0 == ncplane_destroy(n));
+  }
+
+  SUBCASE("SprixelTooWide") {
+    auto y = nc_->tcache.cellpixy;
     auto x = nc_->tcache.cellpixx + 1;
     std::vector<uint32_t> v(x * y, htole(0xe61c28ff));
     auto ncv = ncvisual_from_rgba(v.data(), y, sizeof(decltype(v)::value_type) * x, x);
@@ -73,7 +103,38 @@ TEST_CASE("Bitmaps") {
     };
     CHECK(nullptr == ncvisual_render(nc_, ncv, &vopts));
     CHECK(0 == notcurses_render(nc_));
-sleep(2);
+    ncvisual_destroy(ncv);
+    CHECK(0 == ncplane_destroy(n));
+  }
+
+  // should not be able to emit glyphs to a sprixelated plane
+  SUBCASE("SprixelNoGlyphs") {
+    auto y = nc_->tcache.cellpixy;
+    auto x = nc_->tcache.cellpixx;
+    std::vector<uint32_t> v(x * y, htole(0xe61c28ff));
+    auto ncv = ncvisual_from_rgba(v.data(), y, sizeof(decltype(v)::value_type) * x, x);
+    REQUIRE(nullptr != ncv);
+    struct ncplane_options nopts = {
+      .y = 0, .x = 0,
+      .rows = 1, .cols = 1,
+      .userptr = nullptr, .name = "small", .resizecb = nullptr,
+      .flags = 0, .margin_b = 0, .margin_r = 0,
+    };
+    auto n = ncplane_create(n_, &nopts);
+    struct ncvisual_options vopts = {
+      .n = n,
+      .scaling = NCSCALE_NONE,
+      .y = 0,
+      .x = 0,
+      .begy = 0, .begx = 0,
+      .leny = 0, .lenx = 0,
+      .blitter = NCBLIT_PIXEL,
+      .flags = NCVISUAL_OPTION_NODEGRADE,
+      .transcolor = 0,
+    };
+    CHECK(nullptr != ncvisual_render(nc_, ncv, &vopts));
+    CHECK(0 > ncplane_putchar_yx(n, ' ', 0, 0));
+    CHECK(0 == notcurses_render(nc_));
     ncvisual_destroy(ncv);
     CHECK(0 == ncplane_destroy(n));
   }