normal: reenable ncvisual_from_plane()

src/demo/normal.c

@@ -73,8 +73,7 @@ int normal_demo(struct notcurses* nc){
   }
   free(rgba);
   rgba = NULL;
-  // FIXME ncvisual_from_plane is failing
-  /*ncv = ncvisual_from_plane(n, 0, 0, -1, -1);
+  ncv = ncvisual_from_plane(n, 0, 0, -1, -1);
   if(!ncv){
     goto err;
   }
@@ -86,7 +85,7 @@ int normal_demo(struct notcurses* nc){
       goto err;
     }
     DEMO_RENDER(nc);
-  }*/
+  }
   ncvisual_destroy(ncv);
   ncplane_destroy(n);
   return 0;

src/lib/visual.cpp

@@ -113,6 +113,12 @@ auto ncvisual_from_plane(const ncplane* n, int begy, int begx, int leny, int len
   }
   int dimy, dimx;
   ncplane_dim_yx(n, &dimy, &dimx);
+  if(lenx == -1){
+    lenx = n->lenx - begx;
+  }
+  if(leny == -1){
+    leny = n->leny - begy;
+  }
   auto* ncv = ncvisual_from_rgba(n->nc, rgba, leny, lenx * 4, lenx);
   if(ncv == nullptr){
     free(rgba);