vim-patch:8.2.1995: the popup menu can cause too much redrawing

Problem:    The popup menu can cause too much redrawing.
Solution:   Reduce the length of the displayed text. (Yasuhiro Matsumoto,
            closes vim/vim#7306)
https://github.com/vim/vim/commit/714cbe5b212abbecb578b90424d89f47142e8f25

1 files changed, 13 insertions, 5 deletions

diff --git a/src/nvim/popupmnu.c b/src/nvim/popupmnu.c
index ac0c1f6eb1..f242b7d71a 100644
--- a/src/nvim/popupmnu.c
+++ b/src/nvim/popupmnu.c
@@ -376,6 +376,8 @@ void pum_display(pumitem_T *array, int size, int selected, bool array_changed,
     // the positioning.  Limit this to two times, when there is not much
     // room the window size will keep changing.
   } while (pum_set_selected(selected, redo_count) && (++redo_count <= 2));
+
+  pum_redraw();
 }
 
 /// Redraw the popup menu, using "pum_first" and "pum_selected".
@@ -534,7 +536,17 @@ void pum_redraw(void)
               xfree(st);
               col -= width;
             } else {
-              grid_puts_len(&pum_grid, st, (int)STRLEN(st), row, col, attr);
+              int size = (int)STRLEN(st);
+              int cells = (int)mb_string2cells(st);
+
+              // only draw the text that fits
+              while (size > 0 && col + cells > pum_width + pum_col) {
+                size--;
+                size -= utf_head_off(st, st + size);
+                cells -= utf_ptr2cells(st + size);
+              }
+
+              grid_puts_len(&pum_grid, st, size, row, col, attr);
               xfree(st);
               col += width;
             }
@@ -824,10 +836,6 @@ static int pum_set_selected(int n, int repeat)
     }
   }
 
-  if (!resized) {
-    pum_redraw();
-  }
-
   return resized;
 }