vim-patch:9.0.1626: Visual area not shown when using 'showbreak' (#23978)

Problem:    Visual area not shown when using 'showbreak' and start of line is
            not visible. (Jaehwang Jung)
Solution:   Adjust "fromcol" for the space taken by 'showbreak'.
            (closes vim/vim#12514)

f578ca2c8f

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/drawline.c

@@ -92,7 +92,7 @@ typedef struct {
   int fromcol;               ///< start of inverting
   int tocol;                 ///< end of inverting
 
-  long vcol_sbr;             ///< virtual column after showbreak
+  colnr_T vcol_sbr;          ///< virtual column after showbreak
   bool need_showbreak;       ///< overlong line, skipping first x chars
 
   int char_attr;             ///< attributes for next character
@@ -832,6 +832,12 @@ static void handle_showbreak_and_filler(win_T *wp, winlinevars_T *wlv)
       wlv->need_showbreak = false;
     }
     wlv->vcol_sbr = wlv->vcol + mb_charlen(sbr);
+
+    // Correct start of highlighted area for 'showbreak'.
+    if (wlv->fromcol >= wlv->vcol && wlv->fromcol < wlv->vcol_sbr) {
+      wlv->fromcol = wlv->vcol_sbr;
+    }
+
     // Correct end of highlighted area for 'showbreak',
     // required when 'linebreak' is also set.
     if (wlv->tocol == wlv->vcol) {

src/nvim/grid.c

@@ -540,7 +540,7 @@ void grid_put_linebuf(ScreenGrid *grid, int row, int coloff, int endcol, int cle
     size_t skip = 0;
     if (wp->w_p_nu && wp->w_p_rnu) {
       // do not overwrite the line number, change "123 text" to
-      // "123>>>xt".
+      // "123<<<xt".
       while (skip < max_off_from && ascii_isdigit(*linebuf_char[off])) {
         off++;
         skip++;