buffer: add support for virtual text annotations

src/nvim/api/buffer.c

@@ -967,6 +967,85 @@ void nvim_buf_clear_highlight(Buffer buffer,
   bufhl_clear_line_range(buf, (int)src_id, (int)line_start+1, (int)line_end);
 }
 
+
+/// Set the virtual text (annotation) for a buffer line.
+///
+/// By default (and currently the only option) the text will be placed after
+/// the buffer text. Virtual text will never cause reflow, rather virtual
+/// text will be truncated at the end of the screen line. The virtual text will
+/// begin after one cell to the right of the ordinary text, this will contain
+/// the |lcs-eol| char if set, otherwise just be a space.
+///
+/// @param buffer     Buffer handle
+/// @param src_id     Source group to use or 0 to use a new group,
+///                   or -1 for a ungrouped annotation
+/// @param line       Line to annotate with virtual text (zero-indexed)
+/// @param chunks     A list of [text, hl_group] arrays, each representing a
+///                   text chunk with specified highlight. `hl_group` element
+///                   can be omitted for no highlight.
+/// @param opts       Optional parameters. Currently not used.
+/// @param[out] err   Error details, if any
+/// @return The src_id that was used
+Integer nvim_buf_set_virtual_text(Buffer buffer,
+                                  Integer src_id,
+                                  Integer line,
+                                  Array chunks,
+                                  Dictionary opts,
+                                  Error *err)
+  FUNC_API_SINCE(5)
+{
+  buf_T *buf = find_buffer_by_handle(buffer, err);
+  if (!buf) {
+    return 0;
+  }
+
+  if (line < 0 || line >= MAXLNUM) {
+    api_set_error(err, kErrorTypeValidation, "Line number outside range");
+    return 0;
+  }
+
+  if (opts.size > 0) {
+    api_set_error(err, kErrorTypeValidation, "opts dict isn't empty");
+    return 0;
+  }
+
+  VirtText virt_text = KV_INITIAL_VALUE;
+  for (size_t i = 0; i < chunks.size; i++) {
+    if (chunks.items[i].type != kObjectTypeArray) {
+      api_set_error(err, kErrorTypeValidation, "Chunk is not an array");
+      goto free_exit;
+    }
+    Array chunk = chunks.items[i].data.array;
+    if (chunk.size == 0 || chunk.size > 2
+        || chunk.items[0].type != kObjectTypeString
+        || (chunk.size == 2 && chunk.items[1].type != kObjectTypeString)) {
+      api_set_error(err, kErrorTypeValidation,
+                    "Chunk is not an array with one or two strings");
+      goto free_exit;
+    }
+
+    String str = chunk.items[0].data.string;
+    char *text = xstrdup(str.size > 0 ? str.data : "");
+
+    int hl_id = 0;
+    if (chunk.size == 2) {
+      String hl = chunk.items[1].data.string;
+      if (hl.size > 0) {
+        hl_id = syn_check_group((char_u *)hl.data, (int)hl.size);
+      }
+    }
+    kv_push(virt_text, ((VirtTextChunk){ .text = text, .hl_id = hl_id }));
+  }
+
+  src_id = bufhl_add_virt_text(buf, (int)src_id, (linenr_T)line+1,
+                               virt_text);
+  return src_id;
+
+free_exit:
+  kv_destroy(virt_text);
+  return 0;
+}
+
 // Check if deleting lines made the cursor position invalid.
 // Changed the lines from "lo" to "hi" and added "extra" lines (negative if
 // deleted).

src/nvim/buffer.c

@@ -5375,6 +5375,45 @@ void bufhl_add_hl_pos_offset(buf_T *buf,
   }
 }
 
+int bufhl_add_virt_text(buf_T *buf,
+                        int src_id,
+                        linenr_T lnum,
+                        VirtText virt_text)
+{
+  static int next_src_id = 1;
+  if (src_id == 0) {
+    src_id = next_src_id++;
+  }
+
+  BufhlLine *lineinfo = bufhl_tree_ref(&buf->b_bufhl_info, lnum, true);
+
+  bufhl_clear_virttext(&lineinfo->virt_text);
+  if (kv_size(virt_text) > 0) {
+    lineinfo->virt_text_src = src_id;
+    lineinfo->virt_text = virt_text;
+  } else {
+    lineinfo->virt_text_src = 0;
+    // currently not needed, but allow a future caller with
+    // 0 size and non-zero capacity
+    kv_destroy(virt_text);
+  }
+
+  if (0 < lnum && lnum <= buf->b_ml.ml_line_count) {
+    changed_lines_buf(buf, lnum, lnum+1, 0);
+    redraw_buf_later(buf, VALID);
+  }
+  return src_id;
+}
+
+static void bufhl_clear_virttext(VirtText *text)
+{
+  for (size_t i = 0; i < kv_size(*text); i++) {
+    xfree(kv_A(*text, i).text);
+  }
+  kv_destroy(*text);
+  *text = (VirtText)KV_INITIAL_VALUE;
+}
+
 /// Clear bufhl highlights from a given source group and range of lines.
 ///
 /// @param buf The buffer to remove highlights from
@@ -5430,6 +5469,7 @@ void bufhl_clear_line_range(buf_T *buf,
 static BufhlLineStatus bufhl_clear_line(BufhlLine *lineinfo, int src_id,
                                         linenr_T lnum)
 {
+  BufhlLineStatus changed = kBLSUnchanged;
   size_t oldsize = kv_size(lineinfo->items);
   if (src_id < 0) {
     kv_size(lineinfo->items) = 0;
@@ -5445,14 +5485,25 @@ static BufhlLineStatus bufhl_clear_line(BufhlLine *lineinfo, int src_id,
     }
     kv_size(lineinfo->items) = newidx;
   }
+  if (kv_size(lineinfo->items) != oldsize) {
+    changed = kBLSChanged;
+  }
 
-  if (kv_size(lineinfo->items) == 0) {
+  if (kv_size(lineinfo->virt_text) != 0
+      && (src_id < 0 || src_id == lineinfo->virt_text_src)) {
+    bufhl_clear_virttext(&lineinfo->virt_text);
+    lineinfo->virt_text_src = 0;
+    changed = kBLSChanged;
+  }
+
+  if (kv_size(lineinfo->items) == 0 && kv_size(lineinfo->virt_text) == 0) {
     kv_destroy(lineinfo->items);
     return kBLSDeleted;
   }
-  return kv_size(lineinfo->items) != oldsize ? kBLSChanged : kBLSUnchanged;
+  return changed;
 }
 
+
 /// Remove all highlights and free the highlight data
 void bufhl_clear_all(buf_T *buf)
 {
@@ -5527,8 +5578,8 @@ bool bufhl_start_line(buf_T *buf, linenr_T lnum, BufhlLineInfo *info)
     return false;
   }
   info->valid_to = -1;
-  info->entries = lineinfo->items;
+  info->line = lineinfo;
-  return kv_size(info->entries) > 0;
+  return true;
 }
 
 /// get highlighting at column col
@@ -5548,8 +5599,8 @@ int bufhl_get_attr(BufhlLineInfo *info, colnr_T col)
   }
   int attr = 0;
   info->valid_to = MAXCOL;
-  for (size_t i = 0; i < kv_size(info->entries); i++) {
+  for (size_t i = 0; i < kv_size(info->line->items); i++) {
-    BufhlItem entry = kv_A(info->entries, i);
+    BufhlItem entry = kv_A(info->line->items, i);
     if (entry.start <= col && col <= entry.stop) {
       int entry_attr = syn_id2attr(entry.hl_id);
       attr = hl_combine_attr(attr, entry_attr);

src/nvim/bufhl_defs.h

@@ -14,16 +14,23 @@ typedef struct {
   colnr_T stop;  // last column to highlight
 } BufhlItem;
 
-typedef kvec_t(BufhlItem) BufhlItemVec;
+typedef struct {
+  char *text;
+  int hl_id;
+} VirtTextChunk;
+
+typedef kvec_t(VirtTextChunk) VirtText;
 
 typedef struct {
   linenr_T line;
-  BufhlItemVec items;
+  kvec_t(BufhlItem) items;
+  int virt_text_src;
+  VirtText virt_text;
 } BufhlLine;
-#define BUFHLLINE_INIT(l) { l, KV_INITIAL_VALUE }
+#define BUFHLLINE_INIT(l) { l, KV_INITIAL_VALUE, 0,  KV_INITIAL_VALUE }
 
 typedef struct {
-  BufhlItemVec entries;
+  BufhlLine *line;
   int current;
   colnr_T valid_to;
 } BufhlLineInfo;

src/nvim/screen.c

@@ -132,6 +132,15 @@ static schar_T  *current_ScreenLine;
 StlClickDefinition *tab_page_click_defs = NULL;
 long tab_page_click_defs_size = 0;
 
+// for line_putchar. Contains the state that needs to be remembered from
+// putting one character to the next.
+typedef struct {
+  const char_u *p;
+  int prev_c;  // previous Arabic character
+  int prev_c1;  // first composing char for prev_c
+} LineState;
+#define LINE_STATE(p) { p, 0, 0 }
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "screen.c.generated.h"
 #endif
@@ -1731,6 +1740,56 @@ static int compute_foldcolumn(win_T *wp, int col)
   return fdc;
 }
 
+/// Put a single char from an UTF-8 buffer into a line buffer.
+///
+/// Handles composing chars and arabic shaping state.
+static int line_putchar(LineState *s, schar_T *dest, int maxcells, bool rl)
+{
+  const char_u *p = s->p;
+  int cells = utf_ptr2cells(p);
+  int c_len = utfc_ptr2len(p);
+  int u8c, u8cc[MAX_MCO];
+  if (cells > maxcells) {
+    return -1;
+  }
+  u8c = utfc_ptr2char(p, u8cc);
+  if (*p < 0x80 && u8cc[0] == 0) {
+    schar_from_ascii(dest[0], *p);
+    s->prev_c = u8c;
+  } else {
+    if (p_arshape && !p_tbidi && arabic_char(u8c)) {
+      // Do Arabic shaping.
+      int pc, pc1, nc;
+      int pcc[MAX_MCO];
+      int firstbyte = *p;
+
+      // The idea of what is the previous and next
+      // character depends on 'rightleft'.
+      if (rl) {
+        pc = s->prev_c;
+        pc1 = s->prev_c1;
+        nc = utf_ptr2char(p + c_len);
+        s->prev_c1 = u8cc[0];
+      } else {
+        pc = utfc_ptr2char(p + c_len, pcc);
+        nc = s->prev_c;
+        pc1 = pcc[0];
+      }
+      s->prev_c = u8c;
+
+      u8c = arabic_shape(u8c, &firstbyte, &u8cc[0], pc, pc1, nc);
+    } else {
+      s->prev_c = u8c;
+    }
+    schar_from_cc(dest[0], u8c, u8cc);
+  }
+  if (cells > 1) {
+    dest[1][0] = 0;
+  }
+  s->p += c_len;
+  return cells;
+}
+
 /*
  * Display one folded line.
  */
@@ -1863,13 +1922,7 @@ static void fold_line(win_T *wp, long fold_count, foldinfo_T *foldinfo, linenr_T
    *    Right-left text is put in columns 0 - number-col, normal text is put
    *    in columns number-col - window-width.
    */
-  int cells;
-  int u8c, u8cc[MAX_MCO];
   int idx;
-  int c_len;
-  char_u  *p;
-  int prev_c = 0;  // previous Arabic character
-  int prev_c1 = 0;  // first composing char for prev_c
 
   if (wp->w_p_rl) {
     idx = off;
@@ -1877,50 +1930,20 @@ static void fold_line(win_T *wp, long fold_count, foldinfo_T *foldinfo, linenr_T
     idx = off + col;
   }
 
-  // Store multibyte characters in ScreenLines[] et al. correctly.
+  LineState s = LINE_STATE(text);
-  for (p = text; *p != NUL; ) {
+
-    cells = utf_ptr2cells(p);
+  while (*s.p != NUL) {
-    c_len = utfc_ptr2len(p);
+    // TODO(bfredl): cargo-culted from the old Vim code:
-    if (col + cells > wp->w_width - (wp->w_p_rl ? col : 0)) {
+    // if(col + cells > wp->w_width - (wp->w_p_rl ? col : 0)) { break; }
+    // This is obvious wrong. If Vim ever fixes this, solve for "cells" again
+    // in the correct condition.
+    int maxcells = wp->w_width - col - (wp->w_p_rl ? col : 0);
+    int cells = line_putchar(&s, &ScreenLines[idx], maxcells, wp->w_p_rl);
+    if (cells == -1) {
       break;
     }
-    u8c = utfc_ptr2char(p, u8cc);
-    if (*p < 0x80 && u8cc[0] == 0) {
-      schar_from_ascii(ScreenLines[idx], *p);
-      prev_c = u8c;
-    } else {
-      if (p_arshape && !p_tbidi && arabic_char(u8c)) {
-        // Do Arabic shaping.
-        int pc, pc1, nc;
-        int pcc[MAX_MCO];
-        int firstbyte = *p;
-
-        // The idea of what is the previous and next
-        // character depends on 'rightleft'.
-        if (wp->w_p_rl) {
-          pc = prev_c;
-          pc1 = prev_c1;
-          nc = utf_ptr2char(p + c_len);
-          prev_c1 = u8cc[0];
-        } else {
-          pc = utfc_ptr2char(p + c_len, pcc);
-          nc = prev_c;
-          pc1 = pcc[0];
-        }
-        prev_c = u8c;
-
-        u8c = arabic_shape(u8c, &firstbyte, &u8cc[0], pc, pc1, nc);
-      } else {
-        prev_c = u8c;
-      }
-      schar_from_cc(ScreenLines[idx], u8c, u8cc);
-    }
-    if (cells > 1) {
-      ScreenLines[idx + 1][0] = 0;
-    }
     col += cells;
     idx += cells;
-    p += c_len;
   }
 
   /* Fill the rest of the line with the fold filler */
@@ -2215,9 +2238,9 @@ win_line (
   int did_line_attr = 0;
 
   bool search_attr_from_match = false;  // if search_attr is from :match
-  bool has_bufhl = false;               // this buffer has highlight matches
-  int bufhl_attr = 0;                   // attributes desired by bufhl
   BufhlLineInfo bufhl_info;             // bufhl data for this line
+  bool has_bufhl = false;               // this buffer has highlight matches
+  bool do_virttext = false;             // draw virtual text for this line
 
   /* draw_state: items that are drawn in sequence: */
 #define WL_START        0               /* nothing done yet */
@@ -2279,9 +2302,14 @@ win_line (
     }
 
     if (bufhl_start_line(wp->w_buffer, lnum, &bufhl_info)) {
+      if (kv_size(bufhl_info.line->items)) {
         has_bufhl = true;
         extra_check = true;
       }
+      if (kv_size(bufhl_info.line->virt_text)) {
+        do_virttext = true;
+      }
+    }
 
     // Check for columns to display for 'colorcolumn'.
     color_cols = wp->w_buffer->terminal ? NULL : wp->w_p_cc_cols;
@@ -3429,7 +3457,7 @@ win_line (
         }
 
         if (has_bufhl && v > 0) {
-          bufhl_attr = bufhl_get_attr(&bufhl_info, (colnr_T)v);
+          int bufhl_attr = bufhl_get_attr(&bufhl_info, (colnr_T)v);
           if (bufhl_attr != 0) {
             if (!attr_pri) {
               char_attr = hl_combine_attr(char_attr, bufhl_attr);
@@ -3949,40 +3977,87 @@ win_line (
             && (int)wp->w_virtcol <
             wp->w_width * (row - startrow + 1) + v
             && lnum != wp->w_cursor.lnum)
-           || draw_color_col)
+           || draw_color_col || do_virttext)
-          && !wp->w_p_rl
+          && !wp->w_p_rl) {
-          ) {
         int rightmost_vcol = 0;
         int i;
 
-        if (wp->w_p_cuc)
+        VirtText virt_text = do_virttext ? bufhl_info.line->virt_text
+                                        : (VirtText)KV_INITIAL_VALUE;
+        size_t virt_pos = 0;
+        LineState s = LINE_STATE((char_u *)"");
+        int virt_attr = 0;
+
+        // Make sure alignment is the same regardless
+        // if listchars=eol:X is used or not.
+        bool delay_virttext = lcs_eol <= 0;
+
+        if (wp->w_p_cuc) {
           rightmost_vcol = wp->w_virtcol;
-        if (draw_color_col)
+        }
-          /* determine rightmost colorcolumn to possibly draw */
+
-          for (i = 0; color_cols[i] >= 0; ++i)
+        if (draw_color_col) {
-            if (rightmost_vcol < color_cols[i])
+          // determine rightmost colorcolumn to possibly draw
+          for (i = 0; color_cols[i] >= 0; i++) {
+            if (rightmost_vcol < color_cols[i]) {
               rightmost_vcol = color_cols[i];
+            }
+          }
+        }
 
         int cuc_attr = win_hl_attr(wp, HLF_CUC);
         int mc_attr = win_hl_attr(wp, HLF_MC);
 
         while (col < wp->w_width) {
+          int cells = -1;
+          if (do_virttext && !delay_virttext) {
+            if (*s.p == NUL) {
+              if (virt_pos < virt_text.size) {
+                s.p = (char_u *)kv_A(virt_text, virt_pos).text;
+                int hl_id = kv_A(virt_text, virt_pos).hl_id;
+                virt_attr = hl_id > 0 ? syn_id2attr(hl_id) : 0;
+                virt_pos++;
+              } else {
+               do_virttext = false;
+              }
+            }
+            if (*s.p != NUL) {
+              cells = line_putchar(&s, &ScreenLines[off], wp->w_width - col,
+                                   false);
+            }
+          }
+          delay_virttext = false;
+
+          if (cells == -1) {
             schar_from_ascii(ScreenLines[off], ' ');
-          col++;
+            cells = 1;
+          }
+          col += cells;
           if (draw_color_col) {
             draw_color_col = advance_color_col(VCOL_HLC, &color_cols);
           }
 
+          int attr = 0;
           if (wp->w_p_cuc && VCOL_HLC == (long)wp->w_virtcol) {
-            ScreenAttrs[off++] = cuc_attr;
+            attr = cuc_attr;
           } else if (draw_color_col && VCOL_HLC == *color_cols) {
-            ScreenAttrs[off++] = mc_attr;
+            attr = mc_attr;
-          } else {
-            ScreenAttrs[off++] = wp->w_hl_attr_normal;
           }
 
-          if (VCOL_HLC >= rightmost_vcol)
+          if (do_virttext) {
+            attr = hl_combine_attr(attr, virt_attr);
+          }
+
+          ScreenAttrs[off] = attr;
+          if (cells == 2) {
+            ScreenAttrs[off+1] = attr;
+          }
+          off += cells;
+
+          if (VCOL_HLC >= rightmost_vcol && *s.p == NUL
+              && virt_pos >= virt_text.size) {
             break;
+          }
 
           ++vcol;
         }

test/functional/ui/bufhl_spec.lua

@@ -23,7 +23,10 @@ describe('Buffer highlighting', function()
       [7] = {bold = true},
       [8] = {underline = true, bold = true, foreground = Screen.colors.SlateBlue},
       [9] = {foreground = Screen.colors.SlateBlue, underline = true},
-      [10] = {foreground = Screen.colors.Red}
+      [10] = {foreground = Screen.colors.Red},
+      [11] = {foreground = Screen.colors.Grey100, background = Screen.colors.Red},
+      [12] = {foreground = Screen.colors.Blue1},
+      [13] = {background = Screen.colors.LightGrey},
     })
   end)
 
@@ -77,7 +80,7 @@ describe('Buffer highlighting', function()
                                               |
     ]])
 
-    clear_hl(-1, 0 , -1)
+    clear_hl(-1, 0, -1)
     screen:expect([[
       these are some lines                    |
       ^                                        |
@@ -275,4 +278,140 @@ describe('Buffer highlighting', function()
                                               |
     ]])
   end)
+
+  it('supports virtual text annotations', function()
+    local set_virtual_text = curbufmeths.set_virtual_text
+    insert([[
+      1 + 2
+      3 +
+      x = 4]])
+    feed('O<esc>20A5, <esc>gg')
+    screen:expect([[
+      ^1 + 2                                   |
+      3 +                                     |
+      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,                     |
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    local id1 = set_virtual_text(0, 0, {{"=", "Statement"}, {" 3", "Number"}}, {})
+    set_virtual_text(id1, 1, {{"ERROR:", "ErrorMsg"}, {" invalid syntax"}}, {})
+    local id2 = set_virtual_text(0, 2, {{"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."}}, {})
+    neq(id2, id1)
+
+    screen:expect([[
+      ^1 + 2 {3:=}{2: 3}                               |
+      3 + {11:ERROR:} invalid syntax               |
+      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,  Lorem ipsum dolor s|
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    clear_hl(id1, 0, -1)
+    screen:expect([[
+      ^1 + 2                                   |
+      3 +                                     |
+      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,  Lorem ipsum dolor s|
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    -- Handles doublewidth chars, leaving a space if truncating
+    -- in the middle of a char
+    set_virtual_text(id1, 1, {{"暗x事zz速野谷質結育副住新覚丸活解終事", "Comment"}}, {})
+    screen:expect([[
+      ^1 + 2                                   |
+      3 + {12:暗x事zz速野谷質結育副住新覚丸活解終 }|
+      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,  Lorem ipsum dolor s|
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    feed("2Gx")
+    screen:expect([[
+      1 + 2                                   |
+      ^ + {12:暗x事zz速野谷質結育副住新覚丸活解終事}|
+      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,  Lorem ipsum dolor s|
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    -- visual selection doesn't highlight virtual text
+    feed("ggVG")
+    screen:expect([[
+      {13:1 + 2}                                   |
+      {13: +} {12:暗x事zz速野谷質結育副住新覚丸活解終事}|
+      {13:5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5}|
+      {13:, 5, 5, 5, 5, 5, 5, } Lorem ipsum dolor s|
+      ^x{13: = 4}                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+      {7:-- VISUAL LINE --}                       |
+    ]])
+
+    feed("<esc>")
+    screen:expect([[
+      1 + 2                                   |
+       + {12:暗x事zz速野谷質結育副住新覚丸活解終事}|
+      5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,  Lorem ipsum dolor s|
+      ^x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    feed("2Gdd")
+    screen:expect([[
+      1 + 2                                   |
+      ^5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,  Lorem ipsum dolor s|
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    -- listchars=eol:- works, and doesn't shift virtual text
+    command("set list")
+    screen:expect([[
+      1 + 2                                   |
+      ^5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,{1:-} Lorem ipsum dolor s|
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+    clear_hl(-1, 0, -1)
+    screen:expect([[
+      1 + 2                                   |
+      ^5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5|
+      , 5, 5, 5, 5, 5, 5,{1:-}                    |
+      x = 4                                   |
+      {1:~                                       }|
+      {1:~                                       }|
+      {1:~                                       }|
+                                              |
+    ]])
+
+  end)
 end)