fix(screen): correctly draw background and eob with 'rightleft' (#22640)

src/nvim/grid.c

@@ -550,8 +550,7 @@ void grid_put_linebuf(ScreenGrid *grid, int row, int coloff, int endcol, int cle
 
   if (bg_attr) {
     for (int c = col; c < endcol; c++) {
-      linebuf_attr[off_from + (size_t)c] =
+      linebuf_attr[c] = hl_combine_attr(bg_attr, linebuf_attr[c]);
-        hl_combine_attr(bg_attr, linebuf_attr[off_from + (size_t)c]);
     }
   }
 

src/nvim/screen.c

@@ -111,14 +111,14 @@ static int win_fill_end(win_T *wp, int c1, int c2, int off, int width, int row,
                         int attr)
 {
   int nn = off + width;
+  const int endcol = wp->w_grid.cols;
 
-  if (nn > wp->w_grid.cols) {
+  if (nn > endcol) {
-    nn = wp->w_grid.cols;
+    nn = endcol;
   }
 
   if (wp->w_p_rl) {
-    grid_fill(&wp->w_grid, row, endrow, W_ENDCOL(wp) - nn, W_ENDCOL(wp) - off,
+    grid_fill(&wp->w_grid, row, endrow, endcol - nn, endcol - off, c1, c2, attr);
-              c1, c2, attr);
   } else {
     grid_fill(&wp->w_grid, row, endrow, off, nn, c1, c2, attr);
   }
@@ -156,13 +156,12 @@ void win_draw_end(win_T *wp, int c1, int c2, bool draw_margin, int row, int endr
 
   int attr = hl_combine_attr(win_bg_attr(wp), win_hl_attr(wp, (int)hl));
 
+  const int endcol = wp->w_grid.cols;
   if (wp->w_p_rl) {
-    grid_fill(&wp->w_grid, row, endrow, wp->w_wincol, W_ENDCOL(wp) - 1 - n,
+    grid_fill(&wp->w_grid, row, endrow, 0, endcol - 1 - n, c2, c2, attr);
-              c2, c2, attr);
+    grid_fill(&wp->w_grid, row, endrow, endcol - 1 - n, endcol - n, c1, c2, attr);
-    grid_fill(&wp->w_grid, row, endrow, W_ENDCOL(wp) - 1 - n, W_ENDCOL(wp) - n,
-              c1, c2, attr);
   } else {
-    grid_fill(&wp->w_grid, row, endrow, n, wp->w_grid.cols, c1, c2, attr);
+    grid_fill(&wp->w_grid, row, endrow, n, endcol, c1, c2, attr);
   }
 }
 

test/functional/ui/float_spec.lua

@@ -9224,6 +9224,55 @@ describe('float window', function()
       feed('<C-C>')
       screen:expect_unchanged()
     end)
+
+    it('with rightleft and border #22640', function()
+      local float_opts = {relative='editor', width=5, height=3, row=1, col=1, border='single'}
+      meths.open_win(meths.create_buf(false, false), true, float_opts)
+      command('setlocal rightleft')
+      feed('iabc<CR>def<Esc>')
+      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:  cba}{5:│}|
+          {5:│}{1:  ^fed}{5:│}|
+          {5:│}{2:    ~}{5:│}|
+          {5:└─────┘}|
+        ]], float_pos={
+          [4] = {{id = 1001}, "NW", 1, 1, 1, true, 50};
+        }, win_viewport={
+          [2] = {win = {id = 1000}, topline = 0, botline = 2, curline = 0, curcol = 0, linecount = 1};
+          [4] = {win = {id = 1001}, topline = 0, botline = 3, curline = 1, curcol = 2, linecount = 2};
+        }}
+      else
+        screen:expect{grid=[[
+                                                  |
+          {0:~}{5:┌─────┐}{0:                                }|
+          {0:~}{5:│}{1:  cba}{5:│}{0:                                }|
+          {0:~}{5:│}{1:  ^fed}{5:│}{0:                                }|
+          {0:~}{5:│}{2:    ~}{5:│}{0:                                }|
+          {0:~}{5:└─────┘}{0:                                }|
+                                                  |
+        ]]}
+      end
+    end)
   end
 
   describe('with ext_multigrid', function()

test/functional/ui/highlight_spec.lua

@@ -1812,6 +1812,22 @@ describe("'winhighlight' highlight", function()
     ]])
   end)
 
+  it('works for background color in rightleft window in vsplit #22640', function()
+    screen:try_resize(40, 6)
+    insert('aa')
+    command('setlocal rightleft')
+    command('botright vsplit')
+    command('setlocal winhl=Normal:Background1')
+    screen:expect([[
+                       aa│{1:                  ^aa}|
+      {0:                  ~}│{2:                   ~}|
+      {0:                  ~}│{2:                   ~}|
+      {0:                  ~}│{2:                   ~}|
+      {4:[No Name] [+]       }{3:[No Name] [+]       }|
+                                              |
+    ]])
+  end)
+
   it('handles undefined groups', function()
     command("set winhl=Normal:Background1")
     screen:expect([[