patch 8.2.4707: redrawing could be a bit more efficientv8.2.4707

Problem:    Redrawing could be a bit more efficient.
Solution:   Optimize redrawing. (closes #10105)

5 files changed, 41 insertions, 24 deletions

diff --git a/src/change.c b/src/change.c
index afc32b724..bc9195be4 100644
--- a/src/change.c
+++ b/src/change.c
@@ -640,9 +640,13 @@ changed_common(
 	    if (hasAnyFolding(wp))
 		set_topline(wp, wp->w_topline);
 #endif
-	    // Relative numbering may require updating more.
+	    // If lines have been added or removed, relative numbering always
+	    // requires a redraw.
 	    if (wp->w_p_rnu && xtra != 0)
-		redraw_win_later(wp, SOME_VALID);
+	    {
+		wp->w_last_cursor_lnum_rnu = 0;
+		redraw_win_later(wp, VALID);
+	    }
 #ifdef FEAT_SYN_HL
 	    // Cursor line highlighting probably need to be updated with
 	    // "VALID" if it's below the change.
diff --git a/src/edit.c b/src/edit.c
index c52583a8b..53e86ff18 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -293,14 +293,9 @@ edit(
     conceal_check_cursor_line(cursor_line_was_concealed);
 #endif
 
-    // Need to recompute the cursor position, it might move when the cursor
-    // is on a TAB or special character.
-    // ptr2cells() treats a TAB character as double-width.
-    if (ptr2cells(ml_get_cursor()) > 1)
-    {
-	curwin->w_valid &= ~VALID_VIRTCOL;
-	curs_columns(TRUE);
-    }
+    // need to position cursor again when on a TAB
+    if (gchar_cursor() == TAB)
+	curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
 
     /*
      * Enable langmap or IME, indicated by 'iminsert'.
@@ -3149,21 +3144,20 @@ mb_replace_pop_ins(int cc)
 		replace_push(c);
 		break;
 	    }
+
+	    buf[0] = c;
+	    for (i = 1; i < n; ++i)
+		buf[i] = replace_pop();
+	    if (utf_iscomposing(utf_ptr2char(buf)))
+		ins_bytes_len(buf, n);
 	    else
 	    {
-		buf[0] = c;
-		for (i = 1; i < n; ++i)
-		    buf[i] = replace_pop();
-		if (utf_iscomposing(utf_ptr2char(buf)))
-		    ins_bytes_len(buf, n);
-		else
-		{
-		    // Not a composing char, put it back.
-		    for (i = n - 1; i >= 0; --i)
-			replace_push(buf[i]);
-		    break;
-		}
+		// Not a composing char, put it back.
+		for (i = n - 1; i >= 0; --i)
+		    replace_push(buf[i]);
+		break;
 	    }
+
 	}
 }
 
@@ -3702,8 +3696,9 @@ ins_esc(
 
     State = NORMAL;
     trigger_modechanged();
-    // need to position cursor again (e.g. when on a TAB )
-    changed_cline_bef_curs();
+    // need to position cursor again when on a TAB
+    if (gchar_cursor() == TAB)
+	curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
 
     setmouse();
 #ifdef CURSOR_SHAPE
diff --git a/src/testdir/dumps/Test_cursorcolumn_insert_on_tab_3.dump b/src/testdir/dumps/Test_cursorcolumn_insert_on_tab_3.dump
new file mode 100644
index 000000000..9d0cbed96
--- /dev/null
+++ b/src/testdir/dumps/Test_cursorcolumn_insert_on_tab_3.dump
@@ -0,0 +1,8 @@
+|1+0&#ffffff0|2|3|4|5|6|7|8+0&#e0e0e08|9+0&#ffffff0| @65
+|a| @5> |b| @65
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|-+2#0000000&@1| |(|i|n|s|e|r|t|)| |-@1| +0&&@42|2|,|2|-|8| @8|A|l@1| 
diff --git a/src/testdir/test_highlight.vim b/src/testdir/test_highlight.vim
index 51a25242f..3400052a7 100644
--- a/src/testdir/test_highlight.vim
+++ b/src/testdir/test_highlight.vim
@@ -610,6 +610,14 @@ func Test_cursorcolumn_insert_on_tab()
   call TermWait(buf)
   call VerifyScreenDump(buf, 'Test_cursorcolumn_insert_on_tab_2', {})
 
+  call term_sendkeys(buf, "\<C-O>")
+  call TermWait(buf)
+  call VerifyScreenDump(buf, 'Test_cursorcolumn_insert_on_tab_3', {})
+
+  call term_sendkeys(buf, 'i')
+  call TermWait(buf)
+  call VerifyScreenDump(buf, 'Test_cursorcolumn_insert_on_tab_2', {})
+
   call StopVimInTerminal(buf)
   call delete('Xcuc_insert_on_tab')
 endfunc
diff --git a/src/version.c b/src/version.c
index d0205d7e3..bd63e9317 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4707,
+/**/
     4706,
 /**/
     4705,