honor LINES/COLUMNS if TIOCGWINSZ fails #1826

src/lib/notcurses.c

@@ -22,12 +22,6 @@
 
 #define ESC "\x1b"
 
-// there does not exist any true standard terminal size. with that said, we
-// need assume *something* for the case where we're not actually attached to
-// a terminal (mainly unit tests, but also daemon environments).
-static const int DEFAULT_ROWS = 24;
-static const int DEFAULT_COLS = 80;
-
 void notcurses_version_components(int* major, int* minor, int* patch, int* tweak){
   *major = NOTCURSES_VERNUM_MAJOR;
   *minor = NOTCURSES_VERNUM_MINOR;
@@ -222,10 +216,10 @@ int update_term_dimensions(int fd, int* rows, int* cols, tinfo* tcache,
   // if we're not a real tty, we presumably haven't changed geometry, return
   if(fd < 0){
     if(rows){
-      *rows = DEFAULT_ROWS;
+      *rows = tcache->default_rows;
     }
     if(cols){
-      *cols = DEFAULT_COLS;
+      *cols = tcache->default_cols;
     }
     if(tcache){
       tcache->cellpixy = 0;
@@ -1074,9 +1068,6 @@ notcurses* notcurses_core_init(const notcurses_options* opts, FILE* outfp){
     return NULL;
   }
   ret->ttyfd = get_tty_fd(ret->ttyfp);
-  if(ret->ttyfd < 0){
-    fprintf(stderr, "Defaulting to %dx%d (output is not to a terminal)\n", DEFAULT_ROWS, DEFAULT_COLS);
-  }
   if(recursive_lock_init(&ret->pilelock)){
     fprintf(stderr, "Couldn't initialize pile mutex\n");
     free(ret);

src/lib/termdesc.c

@@ -6,6 +6,42 @@
 #include "internal.h"
 #include "input.h"
 
+// there does not exist any true standard terminal size. with that said, we
+// need assume *something* for the case where we're not actually attached to
+// a terminal (mainly unit tests, but also daemon environments). in preference
+// to this, we use the geometries defined by (in order of precedence):
+//
+//  * TIOGWINSZ ioctl(2)
+//  * LINES/COLUMNS environment variables
+//  * lines/cols terminfo variables
+//
+// this function sets up ti->default_rows and ti->default_cols
+static int
+get_default_dimension(const char* envvar, const char* tinfovar, int def){
+  const char* env = getenv(envvar);
+  int num;
+  if(env){
+    num = atoi(env);
+    if(num > 0){
+      return num;
+    }
+  }
+  num = tigetnum(tinfovar);
+  if(num > 0){
+    return num;
+  }
+  return def;
+}
+
+static void
+get_default_geometry(tinfo* ti){
+  ti->default_rows = get_default_dimension("LINES", "lines", 24);
+  ti->default_cols = get_default_dimension("COLUMNS", "cols", 80);
+  loginfo("Default geometry: %d row%s, %d column%s\n",
+          ti->default_rows, ti->default_rows != 1 ? "s" : "",
+          ti->default_cols, ti->default_cols != 1 ? "s" : "");
+}
+
 // we found Sixel support -- set up the API
 static inline void
 setup_sixel_bitmaps(tinfo* ti, int fd){
@@ -388,6 +424,7 @@ int interrogate_terminfo(tinfo* ti, int fd, const char* termname, unsigned utf8,
       return -1;
     }
   }
+  get_default_geometry(ti);
   ti->caps.utf8 = utf8;
   // allow the "rgb" boolean terminfo capability, a COLORTERM environment
   // variable of either "truecolor" or "24bit", or unconditionally enable it

src/lib/termdesc.h

@@ -161,6 +161,9 @@ typedef struct tinfo {
   // furthermore interprets DECSDM in the reverse sense of most terminals
   // (though possibly in conformance with the actual VT340).
   bool sprixel_cursor_hack; // mlterm fixes
+
+  int default_rows; // LINES environment var / lines terminfo / 24
+  int default_cols; // COLUMNS environment var / cols terminfo / 80
 } tinfo;
 
 // retrieve the terminfo(5)-style escape 'e' from tdesc (NULL if undefined).