mojibake: don't stomp right side of boxes

TERMS.md

@@ -0,0 +1,15 @@
+# Terminals and `TERM`
+
+| Terminal | Recommended `TERM` | Notes |
+| -------- | ------ | ----- |
+| Linux console | `linux` | 8 (512 glyph fonts) or 16 (256 glyph fonts) colors max. |
+| FBterm | | |
+| kmscon | | |
+| XTerm | | |
+| XFCE4 Terminal | | |
+| Gnome Terminal | | |
+| Konsole | | |
+| Alacritty | | |
+| Kitty | | |
+| GNU Screen | `screen-256colors` | Must be compiled with `--enable-256color`. |
+| tmux | | |

src/demo/mojibake.c

@@ -3458,7 +3458,7 @@ unicode52(struct ncplane* title, int y){
                              "\xf0\x9f\x85\xbf \xf0\x9f\x85\xbf\ufe0f"
                              "\xf0\x9f\x88\xaf \xf0\x9f\x88\xaf\ufe0f"
                              "\xf0\x9f\x88\x9a \xf0\x9f\x88\x9a\ufe0f"
-                             "\u3299 \u3299\ufe0f \U0001F41D");
+                             "\u3299 \u3299\ufe0f");
   return n;
 }
 
@@ -3511,10 +3511,10 @@ unicode7emoji2(struct ncplane* title, int y){
 struct ncplane*
 makegroup(struct ncplane* title, int y, const char* emoji, const char* name){
   int cols = mbswidth(emoji);
-  if(cols < 0){
-    cols = 1;
+  if(cols < 0){ // take a wild guess on mbswidth() error.
+    cols = strlen(emoji) * 3 / 5; // best by test
   }
-  struct ncplane* n = mojiplane(title, y, 2 + (cols + (planewidth - 1)) / planewidth, name);
+  struct ncplane* n = mojiplane(title, y, 2 + (cols + (planewidth - 3)) / (planewidth - 2), name);
   if(n == NULL){
     return NULL;
   }
@@ -3537,7 +3537,7 @@ makegroup(struct ncplane* title, int y, const char* emoji, const char* name){
     }
     emoji += bytes;
     x += w;
-    if(x >= planewidth - 1){
+    if(x >= planewidth - 2){
       ++y;
       x = 1;
     }

src/lib/blit.c

@@ -1,3 +1,4 @@
+#include <stddef.h>
 #include "internal.h"
 
 static const unsigned char zeroes[] = "\x00\x00\x00\x00";