feat: add support for global statusline

Ref: #9342

Adds the option to have a single global statusline for the current window at the bottom of the screen instead of a statusline at the bottom of every window. Enabled by setting `laststatus = 3`.

Due to the fact that statuslines at the bottom of windows are removed when global statusline is enabled, horizontal separators are used instead to separate horizontal splits. The horizontal separator character is configurable through the`horiz` item in `'fillchars'`. Separator connector characters are also used to connect the horizontal and vertical separators together, which are also configurable through the `horizup`, `horizdown`, `vertleft`, `vertright` and `verthoriz` items in `fillchars`.

The window separators are highlighted using the `WinSeparator` highlight group, which supersedes `VertSplit` and is linked to `VertSplit` by default in order to maintain backwards compatibility.

1 files changed, 43 insertions, 21 deletions

diff --git a/src/nvim/option.c b/src/nvim/option.c
index c8e50d4494..3eb854aded 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -2910,7 +2910,7 @@ ambw_end:
         || check_opt_strings(curbuf->b_p_bt, p_buftype_values, false) != OK) {
       errmsg = e_invarg;
     } else {
-      if (curwin->w_status_height) {
+      if (curwin->w_status_height || global_stl_height()) {
         curwin->w_redr_status = true;
         redraw_later(curwin, VALID);
       }
@@ -3553,16 +3553,22 @@ static char *set_chars_option(win_T *wp, char_u **varp, bool set)
   struct chars_tab *tab;
 
   struct chars_tab fcs_tab[] = {
-    { &wp->w_p_fcs_chars.stl,     "stl",      ' '  },
-    { &wp->w_p_fcs_chars.stlnc,   "stlnc",    ' '  },
-    { &wp->w_p_fcs_chars.vert,    "vert",     9474 },  // │
-    { &wp->w_p_fcs_chars.fold,    "fold",     183  },  // ·
-    { &wp->w_p_fcs_chars.foldopen,   "foldopen",  '-'  },
-    { &wp->w_p_fcs_chars.foldclosed, "foldclose", '+'  },
-    { &wp->w_p_fcs_chars.foldsep,    "foldsep",   9474 },  // │
-    { &wp->w_p_fcs_chars.diff,    "diff",     '-'  },
-    { &wp->w_p_fcs_chars.msgsep,  "msgsep",   ' '  },
-    { &wp->w_p_fcs_chars.eob,     "eob",      '~'  },
+    { &wp->w_p_fcs_chars.stl,        "stl",        ' '  },
+    { &wp->w_p_fcs_chars.stlnc,      "stlnc",      ' '  },
+    { &wp->w_p_fcs_chars.horiz,      "horiz",      9472 },  // ─
+    { &wp->w_p_fcs_chars.horizup,    "horizup",    9524 },  // ┴
+    { &wp->w_p_fcs_chars.horizdown,  "horizdown",  9516 },  // ┬
+    { &wp->w_p_fcs_chars.vert,       "vert",       9474 },  // │
+    { &wp->w_p_fcs_chars.vertleft,   "vertleft",   9508 },  // ┤
+    { &wp->w_p_fcs_chars.vertright,  "vertright",  9500 },  // ├
+    { &wp->w_p_fcs_chars.verthoriz,  "verthoriz",  9532 },  // ┼
+    { &wp->w_p_fcs_chars.fold,       "fold",       183  },  // ·
+    { &wp->w_p_fcs_chars.foldopen,   "foldopen",   '-'  },
+    { &wp->w_p_fcs_chars.foldclosed, "foldclose",  '+'  },
+    { &wp->w_p_fcs_chars.foldsep,    "foldsep",    9474 },  // │
+    { &wp->w_p_fcs_chars.diff,       "diff",       '-'  },
+    { &wp->w_p_fcs_chars.msgsep,     "msgsep",     ' '  },
+    { &wp->w_p_fcs_chars.eob,        "eob",        '~'  },
   };
   struct chars_tab lcs_tab[] = {
     { &wp->w_p_lcs_chars.eol,     "eol",      NUL  },
@@ -3589,15 +3595,17 @@ static char *set_chars_option(win_T *wp, char_u **varp, bool set)
       varp = &p_fcs;
     }
     if (*p_ambw == 'd') {
-      // XXX: If ambiwidth=double then "|" and "·" take 2 columns, which is
-      // forbidden (TUI limitation?). Set old defaults.
-      fcs_tab[2].def = '|';
-      fcs_tab[6].def = '|';
-      fcs_tab[3].def = '-';
-    } else {
-      fcs_tab[2].def = 9474;  // │
-      fcs_tab[6].def = 9474;  // │
-      fcs_tab[3].def = 183;   // ·
+      // XXX: If ambiwidth=double then some characters take 2 columns,
+      // which is forbidden (TUI limitation?). Set old defaults.
+      fcs_tab[2].def  = '-';
+      fcs_tab[3].def  = '-';
+      fcs_tab[4].def  = '-';
+      fcs_tab[5].def  = '|';
+      fcs_tab[6].def  = '|';
+      fcs_tab[7].def  = '|';
+      fcs_tab[8].def  = '+';
+      fcs_tab[9].def  = '-';
+      fcs_tab[12].def = '|';
     }
   }
 
@@ -4474,6 +4482,20 @@ static char *set_num_option(int opt_idx, char_u *varp, long value, char *errbuf,
     // 'winminwidth'
     win_setminwidth();
   } else if (pp == &p_ls) {
+    // When switching to global statusline, decrease topframe height
+    // Also clear the cmdline to remove the ruler if there is one
+    if (value == 3 && old_value != 3) {
+      frame_new_height(topframe, topframe->fr_height - STATUS_HEIGHT, false, false);
+      (void)win_comp_pos();
+      clear_cmdline = true;
+    }
+    // When switching from global statusline, increase height of topframe by STATUS_HEIGHT
+    // in order to to re-add the space that was previously taken by the global statusline
+    if (old_value == 3 && value != 3) {
+      frame_new_height(topframe, topframe->fr_height + STATUS_HEIGHT, false, false);
+      (void)win_comp_pos();
+    }
+
     last_status(false);  // (re)set last window status line.
   } else if (pp == &p_stal) {
     // (re)set tab page line
@@ -5645,7 +5667,7 @@ static int put_setbool(FILE *fd, char *cmd, char *name, int value)
 
 void comp_col(void)
 {
-  int last_has_status = (p_ls == 2 || (p_ls == 1 && !ONE_WINDOW));
+  int last_has_status = (p_ls > 1 || (p_ls == 1 && !ONE_WINDOW));
 
   sc_col = 0;
   ru_col = 0;