ui/compositor: add redraws needed due to intersected doublewidth chars.

src/nvim/api/ui.c

@@ -461,7 +461,7 @@ static void remote_ui_put(UI *ui, const char *cell)
 static void remote_ui_raw_line(UI *ui, Integer grid, Integer row,
                                Integer startcol, Integer endcol,
                                Integer clearcol, Integer clearattr,
-                               Boolean wrap, const schar_T *chunk,
+                               LineFlags flags, const schar_T *chunk,
                                const sattr_T *attrs)
 {
   UIData *data = ui->data;

src/nvim/api/ui_events.in.h

@@ -92,7 +92,7 @@ void grid_destroy(Integer grid)
 // translate this in to the public grid_line format.
 void raw_line(Integer grid, Integer row, Integer startcol,
               Integer endcol, Integer clearcol, Integer clearattr,
-              Boolean wrap, const schar_T *chunk, const sattr_T *attrs)
+              LineFlags flags, const schar_T *chunk, const sattr_T *attrs)
   FUNC_API_NOEXPORT FUNC_API_COMPOSITOR_IMPL;
 
 void event(char *name, Array args, bool *args_consumed)

src/nvim/popupmnu.c

@@ -363,7 +363,7 @@ void pum_redraw(void)
 
   if (!pum_grid.chars
       || pum_grid.Rows != pum_height || pum_grid.Columns != grid_width) {
-    grid_alloc(&pum_grid, pum_height, grid_width, !moved);
+    grid_alloc(&pum_grid, pum_height, grid_width, !moved, false);
     ui_call_grid_resize(pum_grid.handle, pum_grid.Columns, pum_grid.Rows);
   } else if (moved) {
     grid_invalidate(&pum_grid);

src/nvim/screen.c

@@ -5316,7 +5316,7 @@ void grid_puts(ScreenGrid *grid, char_u *text, int row, int col, int attr)
 }
 
 static int put_dirty_row = -1;
-static int put_dirty_first = -1;
+static int put_dirty_first = INT_MAX;
 static int put_dirty_last = 0;
 
 /// Start a group of screen_puts_len calls that builds a single screen line.
@@ -5347,8 +5347,6 @@ void grid_puts_len(ScreenGrid *grid, char_u *text, int textlen, int row,
   int prev_c = 0;                       /* previous Arabic character */
   int pc, nc, nc1;
   int pcc[MAX_MCO];
-  int force_redraw_this;
-  int force_redraw_next = FALSE;
   int need_redraw;
   bool do_flush = false;
 
@@ -5371,16 +5369,10 @@ void grid_puts_len(ScreenGrid *grid, char_u *text, int textlen, int row,
 
   /* When drawing over the right halve of a double-wide char clear out the
    * left halve.  Only needed in a terminal. */
-  if (col > 0 && col < grid->Columns && grid_fix_col(grid, col, row) != col) {
+  if (grid != &default_grid && col == 0 && grid_invalid_row(grid, row)) {
-    schar_from_ascii(grid->chars[off - 1], ' ');
-    grid->attrs[off - 1] = 0;
     // redraw the previous cell, make it empty
-    if (put_dirty_first == -1) {
+    put_dirty_first = -1;
-      put_dirty_first = col-1;
+    put_dirty_last = MAX(put_dirty_last, 1);
-    }
-    put_dirty_last = col+1;
-    // force the cell at "col" to be redrawn
-    force_redraw_next = true;
   }
 
   max_off = grid->line_offset[row] + grid->Columns;
@@ -5428,15 +5420,12 @@ void grid_puts_len(ScreenGrid *grid, char_u *text, int textlen, int row,
     schar_from_cc(buf, u8c, u8cc);
 
 
-    force_redraw_this = force_redraw_next;
-    force_redraw_next = FALSE;
-
     need_redraw = schar_cmp(grid->chars[off], buf)
                   || (mbyte_cells == 2 && grid->chars[off + 1][0] != 0)
                   || grid->attrs[off] != attr
                   || exmode_active;
 
-    if (need_redraw || force_redraw_this) {
+    if (need_redraw) {
       // When at the end of the text and overwriting a two-cell
       // character with a one-cell character, need to clear the next
       // cell.  Also when overwriting the left halve of a two-cell char
@@ -5460,9 +5449,7 @@ void grid_puts_len(ScreenGrid *grid, char_u *text, int textlen, int row,
         grid->chars[off + 1][0] = 0;
         grid->attrs[off + 1] = attr;
       }
-      if (put_dirty_first == -1 || col < put_dirty_first) {
+      put_dirty_first = MIN(put_dirty_first, col);
-        put_dirty_first = col;
-      }
       put_dirty_last = MAX(put_dirty_last, col+mbyte_cells);
     }
 
@@ -5491,14 +5478,14 @@ void grid_puts_len(ScreenGrid *grid, char_u *text, int textlen, int row,
 void grid_puts_line_flush(ScreenGrid *grid, bool set_cursor)
 {
   assert(put_dirty_row != -1);
-  if (put_dirty_first != -1) {
+  if (put_dirty_first < put_dirty_last) {
     if (set_cursor) {
       ui_grid_cursor_goto(grid->handle, put_dirty_row,
                           MIN(put_dirty_last, grid->Columns-1));
     }
     ui_line(grid, put_dirty_row, put_dirty_first, put_dirty_last,
             put_dirty_last, 0, false);
-    put_dirty_first = -1;
+    put_dirty_first = INT_MAX;
     put_dirty_last = 0;
   }
   put_dirty_row = -1;
@@ -5870,9 +5857,7 @@ void grid_fill(ScreenGrid *grid, int start_row, int end_row, int start_col,
     if (dirty_last > dirty_first) {
       // TODO(bfredl): support a cleared suffix even with a batched line?
       if (put_dirty_row == row) {
-        if (put_dirty_first == -1 || dirty_first < put_dirty_first) {
+        put_dirty_first = MIN(put_dirty_first, dirty_first);
-          put_dirty_first = dirty_first;
-        }
         put_dirty_last = MAX(put_dirty_last, dirty_last);
       } else {
         int last = c2 != ' ' ? dirty_last : dirty_first + (c1 != ' ');
@@ -5958,7 +5943,7 @@ void win_grid_alloc(win_T *wp)
       || grid->Rows != rows
       || grid->Columns != cols) {
     if (want_allocation) {
-      grid_alloc(grid, rows, cols, true);
+      grid_alloc(grid, rows, cols, true, true);
     } else {
       // Single grid mode, all rendering will be redirected to default_grid.
       // Only keep track of the size and offset of the window.
@@ -6054,7 +6039,7 @@ retry:
   // Continuing with the old arrays may result in a crash, because the
   // size is wrong.
 
-  grid_alloc(&default_grid, Rows, Columns, !doclear);
+  grid_alloc(&default_grid, Rows, Columns, !doclear, true);
   StlClickDefinition *new_tab_page_click_defs = xcalloc(
       (size_t)Columns, sizeof(*new_tab_page_click_defs));
 
@@ -6088,7 +6073,7 @@ retry:
   }
 }
 
-void grid_alloc(ScreenGrid *grid, int rows, int columns, bool copy)
+void grid_alloc(ScreenGrid *grid, int rows, int columns, bool copy, bool valid)
 {
   int new_row;
   ScreenGrid new = *grid;
@@ -6106,7 +6091,7 @@ void grid_alloc(ScreenGrid *grid, int rows, int columns, bool copy)
     new.line_offset[new_row] = new_row * new.Columns;
     new.line_wraps[new_row] = false;
 
-    grid_clear_line(&new, new.line_offset[new_row], columns, true);
+    grid_clear_line(&new, new.line_offset[new_row], columns, valid);
 
     if (copy) {
       // If the screen is not going to be cleared, copy as much as
@@ -6234,6 +6219,12 @@ void grid_invalidate(ScreenGrid *grid)
   (void)memset(grid->attrs, -1, grid->Rows * grid->Columns * sizeof(sattr_T));
 }
 
+bool grid_invalid_row(ScreenGrid *grid, int row)
+{
+  return grid->attrs[grid->line_offset[row]] < 0;
+}
+
+
 
 /// Copy part of a grid line for vertically split window.
 static void linecopy(ScreenGrid *grid, int to, int from, int col, int width)

src/nvim/tui/tui.c

@@ -1273,7 +1273,7 @@ static void tui_option_set(UI *ui, String name, Object value)
 
 static void tui_raw_line(UI *ui, Integer g, Integer linerow, Integer startcol,
                          Integer endcol, Integer clearcol, Integer clearattr,
-                         Boolean wrap, const schar_T *chunk,
+                         LineFlags flags, const schar_T *chunk,
                          const sattr_T *attrs)
 {
   TUIData *data = ui->data;
@@ -1295,7 +1295,8 @@ static void tui_raw_line(UI *ui, Integer g, Integer linerow, Integer startcol,
                  (int)clearattr);
   }
 
-  if (wrap && ui->width == grid->width && linerow + 1 < grid->height) {
+  if (flags & kLineFlagWrap && ui->width == grid->width
+      && linerow + 1 < grid->height) {
     // Only do line wrapping if the grid width is equal to the terminal
     // width and the line continuation is within the grid.
 

src/nvim/ui.c

@@ -315,10 +315,16 @@ void ui_set_ext_option(UI *ui, UIExtension ext, bool active)
 void ui_line(ScreenGrid *grid, int row, int startcol, int endcol, int clearcol,
              int clearattr, bool wrap)
 {
+  LineFlags flags = wrap ? kLineFlagWrap : 0;
+  if (startcol == -1) {
+    startcol = 0;
+    flags |= kLineFlagInvalid;
+  }
+
   size_t off = grid->line_offset[row] + (size_t)startcol;
 
-  ui_call_raw_line(grid->handle, row, startcol, endcol,
+  ui_call_raw_line(grid->handle, row, startcol, endcol, clearcol, clearattr,
-             clearcol, clearattr, wrap, (const schar_T *)grid->chars + off,
+                   flags, (const schar_T *)grid->chars + off,
                    (const sattr_T *)grid->attrs + off);
 
   if (p_wd) {  // 'writedelay': flush & delay each time.

src/nvim/ui.h

@@ -34,6 +34,13 @@ EXTERN const char *ui_ext_names[] INIT(= {
 
 typedef struct ui_t UI;
 
+enum {
+  kLineFlagWrap = 1,
+  kLineFlagInvalid = 2,
+};
+
+typedef int LineFlags;
+
 struct ui_t {
   bool rgb;
   bool composed;

src/nvim/ui_bridge.c

@@ -153,14 +153,14 @@ static void ui_bridge_raw_line_event(void **argv)
   UI *ui = UI(argv[0]);
   ui->raw_line(ui, PTR2INT(argv[1]), PTR2INT(argv[2]), PTR2INT(argv[3]),
                PTR2INT(argv[4]), PTR2INT(argv[5]), PTR2INT(argv[6]),
-               PTR2INT(argv[7]), argv[8], argv[9]);
+               (LineFlags)PTR2INT(argv[7]), argv[8], argv[9]);
   xfree(argv[8]);
   xfree(argv[9]);
 }
 static void ui_bridge_raw_line(UI *ui, Integer grid, Integer row,
                                Integer startcol, Integer endcol,
                                Integer clearcol, Integer clearattr,
-                               Boolean wrap, const schar_T *chunk,
+                               LineFlags flags, const schar_T *chunk,
                                const sattr_T *attrs)
 {
   size_t ncol = (size_t)(endcol-startcol);
@@ -168,7 +168,7 @@ static void ui_bridge_raw_line(UI *ui, Integer grid, Integer row,
   sattr_T *hl = xmemdup(attrs, ncol * sizeof(sattr_T));
   UI_BRIDGE_CALL(ui, raw_line, 10, ui, INT2PTR(grid), INT2PTR(row),
                  INT2PTR(startcol), INT2PTR(endcol), INT2PTR(clearcol),
-                 INT2PTR(clearattr), INT2PTR(wrap), c, hl);
+                 INT2PTR(clearattr), INT2PTR(flags), c, hl);
 }
 
 static void ui_bridge_suspend(UI *b)

src/nvim/ui_compositor.c

@@ -217,8 +217,16 @@ static void ui_comp_grid_cursor_goto(UI *ui, Integer grid_handle,
 /// do something more efficient (where efficiency means smaller deltas to
 /// the downstream UI.)
 static void compose_line(Integer row, Integer startcol, Integer endcol,
-                         bool wrap)
+                         LineFlags flags)
 {
+  // in case we start on the right half of a double-width char, we need to
+  // check the left half. But skip it in output if it wasn't doublewidth.
+  int skip = 0;
+  if (startcol > 0 && (flags & kLineFlagInvalid)) {
+    startcol--;
+    skip = 1;
+  }
+
   int col = (int)startcol;
   ScreenGrid *grid = NULL;
 
@@ -247,15 +255,37 @@ static void compose_line(Integer row, Integer startcol, Integer endcol,
                  + (size_t)(col-grid->comp_col);
     memcpy(linebuf+(col-startcol), grid->chars+off, n * sizeof(*linebuf));
     memcpy(attrbuf+(col-startcol), grid->attrs+off, n * sizeof(*attrbuf));
+
+    // Tricky: if overlap caused a doublewidth char to get cut-off, must
+    // replace the visible half with a space.
+    if (linebuf[col-startcol][0] == NUL) {
+      linebuf[col-startcol][0] = ' ';
+      linebuf[col-startcol][1] = NUL;
+    } else if (n > 1 && linebuf[col-startcol+1][0] == NUL) {
+      skip = 0;
+    }
+    if (grid->comp_col+grid->Columns > until
+        && grid->chars[off+n][0] == NUL) {
+      linebuf[until-1-startcol][0] = ' ';
+      linebuf[until-1-startcol][1] = '\0';
+      if (col == startcol && n == 1) {
+        skip = 0;
+      }
+    }
     col = until;
   }
   assert(endcol <= chk_width);
   assert(row < chk_height);
+
+  if (!(grid && grid == &default_grid)) {
     // TODO(bfredl): too conservative, need check
     // grid->line_wraps if grid->Width == Width
-  wrap = wrap && grid && grid->handle == 1;
+    flags = flags & ~kLineFlagWrap;
-  ui_composed_call_raw_line(1, row, startcol, endcol, endcol, 0, wrap,
+  }
-                            (const schar_T *)linebuf, (const sattr_T *)attrbuf);
+
+  ui_composed_call_raw_line(1, row, startcol+skip, endcol, endcol, 0, flags,
+                            (const schar_T *)linebuf+skip,
+                            (const sattr_T *)attrbuf+skip);
 }
 
 static void compose_area(Integer startrow, Integer endrow,
@@ -264,39 +294,35 @@ static void compose_area(Integer startrow, Integer endrow,
   endrow = MIN(endrow, default_grid.Rows);
   endcol = MIN(endcol, default_grid.Columns);
   for (int r = (int)startrow; r < endrow; r++) {
-    compose_line(r, startcol, endcol, false);
+    compose_line(r, startcol, endcol, kLineFlagInvalid);
   }
 }
 
 
-static void draw_line(ScreenGrid *grid, Integer row, Integer startcol,
-                      Integer endcol, Integer clearcol, Integer clearattr,
-                      bool wrap, const schar_T *chunk, const sattr_T *attrs)
-{
-  row += grid->comp_row;
-  startcol += grid->comp_col;
-  endcol += grid->comp_col;
-  clearcol += grid->comp_col;
-  wrap = wrap && grid->handle == 1;
-  assert(clearcol <= default_grid.Columns);
-  if (kv_size(layers) > grid->comp_index+1) {
-    compose_line(row, startcol, clearcol, wrap);
-  } else {
-    ui_composed_call_raw_line(1, row, startcol, endcol, clearcol, clearattr,
-                              wrap, chunk, attrs);
-  }
-}
-
 static void ui_comp_raw_line(UI *ui, Integer grid, Integer row,
                              Integer startcol, Integer endcol,
-                             Integer clearcol, Integer clearattr, bool wrap,
+                             Integer clearcol, Integer clearattr,
-                             const schar_T *chunk, const sattr_T *attrs)
+                             LineFlags flags, const schar_T *chunk,
+                             const sattr_T *attrs)
 {
   if (!ui_comp_should_draw() || !ui_comp_set_grid((int)grid)) {
     return;
   }
-  draw_line(curgrid, row, startcol, endcol, clearcol, clearattr, wrap, chunk,
+
-            attrs);
+  row += curgrid->comp_row;
+  startcol += curgrid->comp_col;
+  endcol += curgrid->comp_col;
+  clearcol += curgrid->comp_col;
+  if (curgrid != &default_grid) {
+    flags = flags & ~kLineFlagWrap;
+  }
+  assert(clearcol <= default_grid.Columns);
+  if (flags & kLineFlagInvalid || kv_size(layers) > curgrid->comp_index+1) {
+    compose_line(row, startcol, clearcol, flags);
+  } else {
+    ui_composed_call_raw_line(1, row, startcol, endcol, clearcol, clearattr,
+                              flags, chunk, attrs);
+  }
 }
 
 /// The screen is invalid and will soon be cleared