apply_term_heuristics: no braille on linux console #1334

src/lib/internal.h

@@ -264,20 +264,21 @@ typedef struct tinfo {
   char* smkx;     // enter keypad transmit mode (keypad_xmit)
   char* rmkx;     // leave keypad transmit mode (keypad_local)
   char* getm;     // get mouse events
+  char* smcup;    // enter alternate mode
+  char* rmcup;    // restore primary mode
   bool RGBflag;   // "RGB" flag for 24bpc truecolor
   bool CCCflag;   // "CCC" flag for palette set capability
   bool BCEflag;   // "BCE" flag for erases with background color
   bool AMflag;    // "AM" flag for automatic movement to next line
   bool utf8;      // are we using utf-8 encoding, as hoped?
-  char* smcup;    // enter alternate mode
-  char* rmcup;    // restore primary mode
 
   // kitty interprets an RGB background that matches the default background
   // color *as* the default background, meaning it'll be translucent if
   // background_opaque is in use. detect this, and avoid the default if so.
   // bg_collides_default is either 0x0000000 or 0x1RRGGBB.
   uint32_t bg_collides_default;
-  bool sextants;  // do we have Unicode 13 sextant support?
+  bool sextants;  // do we have (good, vetted) Unicode 13 sextant support?
+  bool braille;   // do we have Braille support? (linux console does not)
 } tinfo;
 
 typedef struct ncinputlayer {

src/lib/terminfo.c

@@ -50,6 +50,7 @@ apply_term_heuristics(tinfo* ti, const char* termname){
     // setupterm interprets a missing/empty TERM variable as the special value “unknown”.
     termname = "unknown";
   }
+  ti->braille = true;
   if(strstr(termname, "kitty")){ // kitty (https://sw.kovidgoyal.net/kitty/)
     // see https://sw.kovidgoyal.net/kitty/protocol-extensions.html
     // FIXME detect the actual default background color; this assumes it to
@@ -58,6 +59,8 @@ apply_term_heuristics(tinfo* ti, const char* termname){
     ti->sextants = true; // work since bugfix in 0.19.3
   }else if(strstr(termname, "vte") || strstr(termname, "gnome") || strstr(termname, "xfce")){
     ti->sextants = true; // VTE has long enjoyed good sextant support
+  }else if(strcmp(termname, "linux") == 0){
+    ti->braille = false; // no braille, no sextants in linux console
   }
   // run a wcwidth() to guarantee libc Unicode 13 support
   if(wcwidth(L'🬸') < 0){