feat(float): implement footer

Problem: Now way to show text at the bottom part of floating window
  border (a.k.a. "footer").

Solution: Allows `footer` and `footer_pos` config fields similar to
  `title` and `title_pos`.

runtime/doc/api.txt

@@ -3138,11 +3138,18 @@ nvim_open_win({buffer}, {enter}, {*config})                  *nvim_open_win()*
                       specified by character: [ ["+", "MyCorner"], ["x",
                       "MyBorder"] ].
 
-                  • title: Title (optional) in window border, String or list.
+                  • title: Title (optional) in window border, string or list.
-                    List is [text, highlight] tuples. if is string the default
+                    List should consist of `[text, highlight]` tuples. If
-                    highlight group is `FloatTitle`.
+                    string, the default highlight group is `FloatTitle`.
-                  • title_pos: Title position must set with title option.
+                  • title_pos: Title position. Must be set with `title`
-                    value can be of `left` `center` `right` default is left.
+                    option. Value can be one of "left", "center", or "right".
+                    Default is `"left"`.
+                  • footer: Footer (optional) in window border, string or
+                    list. List should consist of `[text, highlight]` tuples.
+                    If string, the default highlight group is `FloatTitle`.
+                  • footer_pos: Footer position. Must be set with `footer`
+                    option. Value can be one of "left", "center", or "right".
+                    Default is `"left"`.
                   • noautocmd: If true then no buffer-related autocommand
                     events such as |BufEnter|, |BufLeave| or |BufWinEnter| may
                     fire from calling this function.

runtime/doc/news.txt

@@ -155,6 +155,9 @@ The following new APIs and features were added.
 • New RPC client type `msgpack-rpc` is added for `nvim_set_client_info` to
   support fully MessagePack-RPC compliant clients.
 
+• Floating windows can now show footer with new `footer` and `footer_pos`
+  config fields.
+
 ==============================================================================
 CHANGED FEATURES                                                 *news-changed*
 

runtime/lua/vim/_meta/api.lua

@@ -1551,11 +1551,18 @@ function vim.api.nvim_open_term(buffer, opts) end
 ---                   specified by character: [ ["+", "MyCorner"], ["x",
 ---                   "MyBorder"] ].
 ---
----               • title: Title (optional) in window border, String or list.
+---               • title: Title (optional) in window border, string or list.
----                 List is [text, highlight] tuples. if is string the default
+---                 List should consist of `[text, highlight]` tuples. If
----                 highlight group is `FloatTitle`.
+---                 string, the default highlight group is `FloatTitle`.
----               • title_pos: Title position must set with title option.
+---               • title_pos: Title position. Must be set with `title`
----                 value can be of `left` `center` `right` default is left.
+---                 option. Value can be one of "left", "center", or "right".
+---                 Default is `"left"`.
+---               • footer: Footer (optional) in window border, string or
+---                 list. List should consist of `[text, highlight]` tuples.
+---                 If string, the default highlight group is `FloatTitle`.
+---               • footer_pos: Footer position. Must be set with `footer`
+---                 option. Value can be one of "left", "center", or "right".
+---                 Default is `"left"`.
 ---               • noautocmd: If true then no buffer-related autocommand
 ---                 events such as `BufEnter`, `BufLeave` or `BufWinEnter` may
 ---                 fire from calling this function.

runtime/lua/vim/_meta/api_keysets.lua

@@ -108,6 +108,8 @@ error('Cannot require a meta file')
 --- @field border? any
 --- @field title? any
 --- @field title_pos? string
+--- @field footer? any
+--- @field footer_pos? string
 --- @field style? string
 --- @field noautocmd? boolean
 

src/nvim/api/keysets.h

@@ -99,6 +99,8 @@ typedef struct {
   Object border;
   Object title;
   String title_pos;
+  Object footer;
+  String footer_pos;
   String style;
   Boolean noautocmd;
 } Dict(float_config);

src/nvim/api/win_config.c

@@ -145,11 +145,18 @@
 ///     By default, `FloatBorder` highlight is used, which links to `WinSeparator`
 ///     when not defined.  It could also be specified by character:
 ///       [ ["+", "MyCorner"], ["x", "MyBorder"] ].
-///   - title: Title (optional) in window border, String or list.
+///   - title: Title (optional) in window border, string or list.
-///     List is [text, highlight] tuples. if is string the default
+///     List should consist of `[text, highlight]` tuples.
-///     highlight group is `FloatTitle`.
+///     If string, the default highlight group is `FloatTitle`.
-///   - title_pos: Title position must set with title option.
+///   - title_pos: Title position. Must be set with `title` option.
-///     value can be of `left` `center` `right` default is left.
+///     Value can be one of "left", "center", or "right".
+///     Default is `"left"`.
+///   - footer: Footer (optional) in window border, string or list.
+///     List should consist of `[text, highlight]` tuples.
+///     If string, the default highlight group is `FloatTitle`.
+///   - footer_pos: Footer position. Must be set with `footer` option.
+///     Value can be one of "left", "center", or "right".
+///     Default is `"left"`.
 ///   - noautocmd: If true then no buffer-related autocommand events such as
 ///                  |BufEnter|, |BufLeave| or |BufWinEnter| may fire from
 ///                  calling this function.
@@ -247,11 +254,19 @@ Dictionary config_put_bordertext(Dictionary config, FloatConfig *fconfig,
   AlignTextPos align;
   char *field_name;
   char *field_pos_name;
-  if (bordertext_type == kBorderTextTitle) {
+  switch (bordertext_type) {
+  case kBorderTextTitle:
     chunks = fconfig->title_chunks;
     align = fconfig->title_pos;
     field_name = "title";
     field_pos_name = "title_pos";
+    break;
+  case kBorderTextFooter:
+    chunks = fconfig->footer_chunks;
+    align = fconfig->footer_pos;
+    field_name = "footer";
+    field_pos_name = "footer_pos";
+    break;
   }
 
   Array bordertext = ARRAY_DICT_INIT;
@@ -345,6 +360,9 @@ Dictionary nvim_win_get_config(Window window, Error *err)
       if (config->title) {
         rv = config_put_bordertext(rv, config, kBorderTextTitle);
       }
+      if (config->footer) {
+        rv = config_put_bordertext(rv, config, kBorderTextFooter);
+      }
     }
   }
 
@@ -410,10 +428,17 @@ static void parse_bordertext(Object bordertext, BorderTextType bordertext_type,
   bool *is_present;
   VirtText *chunks;
   int *width;
-  if (bordertext_type == kBorderTextTitle) {
+  switch (bordertext_type) {
+  case kBorderTextTitle:
     is_present = &fconfig->title;
     chunks = &fconfig->title_chunks;
     width = &fconfig->title_width;
+    break;
+  case kBorderTextFooter:
+    is_present = &fconfig->footer;
+    chunks = &fconfig->footer_chunks;
+    width = &fconfig->footer_width;
+    break;
   }
 
   if (bordertext.type == kObjectTypeString) {
@@ -449,8 +474,13 @@ static bool parse_bordertext_pos(String bordertext_pos, BorderTextType bordertex
                                  FloatConfig *fconfig, Error *err)
 {
   AlignTextPos *align;
-  if (bordertext_type == kBorderTextTitle) {
+  switch (bordertext_type) {
+  case kBorderTextTitle:
     align = &fconfig->title_pos;
+    break;
+  case kBorderTextFooter:
+    align = &fconfig->footer_pos;
+    break;
   }
 
   if (bordertext_pos.size == 0) {
@@ -467,8 +497,13 @@ static bool parse_bordertext_pos(String bordertext_pos, BorderTextType bordertex
   } else if (strequal(pos, "right")) {
     *align = kAlignRight;
   } else {
-    if (bordertext_type == kBorderTextTitle) {
+    switch (bordertext_type) {
+    case kBorderTextTitle:
       api_set_error(err, kErrorTypeValidation, "invalid title_pos value");
+      break;
+    case kBorderTextFooter:
+      api_set_error(err, kErrorTypeValidation, "invalid footer_pos value");
+      break;
     }
     return false;
   }
@@ -559,8 +594,9 @@ static void parse_border_style(Object style,  FloatConfig *fconfig, Error *err)
     String str = style.data.string;
     if (str.size == 0 || strequal(str.data, "none")) {
       fconfig->border = false;
-      // title does not work with border equal none
+      // border text does not work with border equal none
       fconfig->title = false;
+      fconfig->footer = false;
       return;
     }
     for (size_t i = 0; defaults[i].name; i++) {
@@ -750,6 +786,33 @@ static bool parse_float_config(Dict(float_config) *config, FloatConfig *fconfig,
     }
   }
 
+  if (HAS_KEY_X(config, footer)) {
+    // footer only work with border
+    if (!HAS_KEY_X(config, border) && !fconfig->border) {
+      api_set_error(err, kErrorTypeException, "footer requires border to be set");
+      return false;
+    }
+
+    if (fconfig->footer) {
+      clear_virttext(&fconfig->footer_chunks);
+    }
+
+    parse_bordertext(config->footer, kBorderTextFooter, fconfig, err);
+    if (ERROR_SET(err)) {
+      return false;
+    }
+
+    // handles unset 'footer_pos' same as empty string
+    if (!parse_bordertext_pos(config->footer_pos, kBorderTextFooter, fconfig, err)) {
+      return false;
+    }
+  } else {
+    if (HAS_KEY_X(config, footer_pos)) {
+      api_set_error(err, kErrorTypeException, "footer_pos requires footer to be set");
+      return false;
+    }
+  }
+
   if (HAS_KEY_X(config, border)) {
     parse_border_style(config->border, fconfig, err);
     if (ERROR_SET(err)) {

src/nvim/buffer_defs.h

@@ -938,6 +938,7 @@ typedef enum {
 
 typedef enum {
   kBorderTextTitle = 0,
+  kBorderTextFooter = 1,
 } BorderTextType;
 
 typedef struct {
@@ -952,14 +953,18 @@ typedef struct {
   int zindex;
   WinStyle style;
   bool border;
-  bool title;
   bool shadow;
   schar_T border_chars[8];
   int border_hl_ids[8];
   int border_attr[8];
+  bool title;
   AlignTextPos title_pos;
   VirtText title_chunks;
   int title_width;
+  bool footer;
+  AlignTextPos footer_pos;
+  VirtText footer_chunks;
+  int footer_width;
   bool noautocmd;
 } FloatConfig;
 

src/nvim/drawscreen.c

@@ -782,10 +782,17 @@ static void win_redr_border(win_T *wp)
     if (adj[3]) {
       grid_put_schar(grid, irow + adj[0], 0, chars[6], attrs[6]);
     }
+
     for (int i = 0; i < icol; i++) {
       int ic = (i == 0 && !adj[3] && chars[6][0]) ? 6 : 5;
       grid_put_schar(grid, irow + adj[0], i + adj[3], chars[ic], attrs[ic]);
     }
+
+    if (wp->w_float_config.footer) {
+      int footer_col = win_get_bordertext_col(icol, wp->w_float_config.footer_width,
+                                              wp->w_float_config.footer_pos);
+      win_redr_bordertext(wp, grid, wp->w_float_config.footer_chunks, grid->rows - 1, footer_col);
+    }
     if (adj[1]) {
       grid_put_schar(grid, irow + adj[0], icol + adj[3], chars[4], attrs[4]);
     }

src/nvim/window.c

@@ -5239,8 +5239,9 @@ static void win_free(win_T *wp, tabpage_T *tp)
     }
   }
 
-  // free the border title text
+  // free the border text
   clear_virttext(&wp->w_float_config.title_chunks);
+  clear_virttext(&wp->w_float_config.footer_chunks);
 
   clear_matches(wp);
 

test/functional/ui/float_spec.lua

@@ -1851,6 +1851,39 @@ describe('float window', function()
       eq('center', title_pos)
     end)
 
+    it('validates footer footer_pos', function()
+      local buf = meths.create_buf(false,false)
+      eq("footer requires border to be set",
+         pcall_err(meths.open_win,buf, false, {
+          relative='editor', width=9, height=2, row=2, col=5, footer='Footer',
+         }))
+      eq("footer_pos requires footer to be set",
+         pcall_err(meths.open_win,buf, false, {
+          relative='editor', width=9, height=2, row=2, col=5,
+          border='single', footer_pos='left',
+         }))
+    end)
+
+    it('validate footer_pos in nvim_win_get_config', function()
+      local footer_pos = exec_lua([[
+        local bufnr = vim.api.nvim_create_buf(false, false)
+        local opts = {
+          relative = 'editor',
+          col = 2,
+          row = 5,
+          height = 2,
+          width = 9,
+          border = 'double',
+          footer = 'Test',
+          footer_pos = 'center'
+        }
+
+        local win_id = vim.api.nvim_open_win(bufnr, true, opts)
+        return vim.api.nvim_win_get_config(win_id).footer_pos
+      ]])
+
+      eq('center', footer_pos)
+    end)
 
     it('border with title', function()
       local buf = meths.create_buf(false, false)
@@ -2033,6 +2066,368 @@ describe('float window', function()
       end
     end)
 
+    it('border with footer', function()
+      local buf = meths.create_buf(false, false)
+      meths.buf_set_lines(buf, 0, -1, true, {' halloj! ',
+                                             ' BORDAA  '})
+      local win = meths.open_win(buf, false, {
+        relative='editor', width=9, height=2, row=2, col=5, border="double",
+        footer = "Left",footer_pos = "left",
+      })
+
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔═════════╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚}{11:Left}{5:═════╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔═════════╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚}{11:Left}{5:═════╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+
+      meths.win_set_config(win, {footer= "Center",footer_pos="center"})
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔═════════╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚═}{11:Center}{5:══╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔═════════╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚═}{11:Center}{5:══╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+
+      meths.win_set_config(win, {footer= "Right",footer_pos="right"})
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔═════════╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚════}{11:Right}{5:╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔═════════╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚════}{11:Right}{5:╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+
+      meths.win_set_config(win, {footer= { {"🦄"},{"BB"}},footer_pos="right"})
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔═════════╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚═════}🦄BB{5:╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔═════════╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚═════}🦄BB{5:╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+    end)
+
+    it('border with title and footer', function()
+      local buf = meths.create_buf(false, false)
+      meths.buf_set_lines(buf, 0, -1, true, {' halloj! ',
+                                             ' BORDAA  '})
+      local win = meths.open_win(buf, false, {
+        relative='editor', width=9, height=2, row=2, col=5, border="double",
+        title = "Left", title_pos = "left", footer = "Right", footer_pos = "right",
+      })
+
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔}{11:Left}{5:═════╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚════}{11:Right}{5:╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔}{11:Left}{5:═════╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚════}{11:Right}{5:╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+
+      meths.win_set_config(win, {title= "Center",title_pos="center",footer= "Center",footer_pos="center"})
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔═}{11:Center}{5:══╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚═}{11:Center}{5:══╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔═}{11:Center}{5:══╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚═}{11:Center}{5:══╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+
+      meths.win_set_config(win, {title= "Right",title_pos="right",footer= "Left",footer_pos="left"})
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔════}{11:Right}{5:╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚}{11:Left}{5:═════╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔════}{11:Right}{5:╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚}{11:Left}{5:═════╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+
+      meths.win_set_config(win, {title= { {"🦄"},{"BB"}},title_pos="right",footer= { {"🦄"},{"BB"}},footer_pos="right"})
+      if multigrid then
+        screen:expect{grid=[[
+        ## grid 1
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [2:----------------------------------------]|
+          [3:----------------------------------------]|
+        ## grid 2
+          ^                                        |
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+          {0:~                                       }|
+        ## grid 3
+                                                  |
+        ## grid 4
+          {5:╔═════}🦄BB{5:╗}|
+          {5:║}{1: halloj! }{5:║}|
+          {5:║}{1: BORDAA  }{5:║}|
+          {5:╚═════}🦄BB{5:╝}|
+        ]], float_pos={
+          [4] = { { id = 1001 }, "NW", 1, 2, 5, true }
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1, sum_scroll_delta = 0};
+          [4] = {win = {id = 1001}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 2, sum_scroll_delta = 0};
+        }}
+      else
+        screen:expect{grid=[[
+          ^                                        |
+          {0:~                                       }|
+          {0:~    }{5:╔═════}🦄BB{5:╗}{0:                        }|
+          {0:~    }{5:║}{1: halloj! }{5:║}{0:                        }|
+          {0:~    }{5:║}{1: BORDAA  }{5:║}{0:                        }|
+          {0:~    }{5:╚═════}🦄BB{5:╝}{0:                        }|
+                                                  |
+        ]]}
+      end
+    end)
+
     it('terminates border on edge of viewport when window extends past viewport', function()
       local buf = meths.create_buf(false, false)
       meths.open_win(buf, false, {relative='editor', width=40, height=7, row=0, col=0, border="single", zindex=201})