[PATCH v2 0/2] MR10888: riched20: Implement EM_LINELENGTH with wParam==-1

[Rose Hellsing (＠axtlos)]

MS Comic Chat requires EM_LINELENGTH with wParam==-1 to be implemented in riched20 to allow typing space characters.

EM_LINELENGTH(-1) returns the number of unselected characters on the line that contains the current selection.

--
  v2: riched20/tests: Add EM_LINELENGTH(-1) tests
      riched20: Implement EM_LINELENGTH with wParam==-1
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10888

[PATCH v2 1/2] riched20: Implement EM_LINELENGTH with wParam==-1

[Rose Hellsing]

From: Rose Hellsing <[e-mail]>

MS Comic Chat requires EM_LINELENGTH with wParam==-1 to be implemented in riched20 to allow typing space characters.

EM_LINELENGTH(-1) returns the number of unselected characters on the line that contains the current selection.
---
 dlls/riched20/editor.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/dlls/riched20/editor.c b/dlls/riched20/editor.c
index 1a0c444579b..e704508f2a5 100644
--- a/dlls/riched20/editor.c
+++ b/dlls/riched20/editor.c
@@ -3806,13 +3806,31 @@ LRESULT editor_handle_message( ME_TextEditor *editor, UINT msg, WPARAM wParam,
     int start_ofs, end_ofs;
     ME_Cursor cursor;
 
-    if (wParam > ME_GetTextLength(editor))
-      return 0;
     if (wParam == -1)
     {
-      FIXME("EM_LINELENGTH: returning number of unselected characters on lines with selection unsupported.\n");
-      return 0;
+      LONG from, to;
+      int line_start, line_end, line_len, result;
+
+      ME_GetSelectionOfs( editor, &from, &to );
+
+      cursor_from_char_ofs( editor, from, &cursor );
+      row = row_from_cursor( &cursor );
+      row_first_cursor( row, &cursor );
+      line_start = ME_GetCursorOfs( &cursor );
+
+      cursor_from_char_ofs( editor, to, &cursor );
+      row = row_from_cursor( &cursor );
+      row_first_cursor( row, &cursor );
+      line_end = ME_GetCursorOfs( &cursor );
+      row_end_cursor( row, &cursor, FALSE );
+      line_len = ME_GetCursorOfs( &cursor ) - line_end;
+
+      result = (from - line_start) + (line_end + line_len - to);
+      TRACE( "EM_LINELENGTH(-1): sel=%ld..%ld result=%d\n", from, to, result );
+      return result;
     }
+    if (wParam > ME_GetTextLength(editor))
+      return 0;
     cursor_from_char_ofs( editor, wParam, &cursor );
     row = row_from_cursor( &cursor );
     row_first_cursor( row, &cursor );
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/10888

[PATCH v2 2/2] riched20/tests: Add EM_LINELENGTH(-1) tests

[Rose Hellsing]

From: Rose Hellsing <[e-mail]>

---
 dlls/riched20/tests/editor.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/dlls/riched20/tests/editor.c b/dlls/riched20/tests/editor.c
index 19cd40aea48..0a7b8ec6ce4 100644
--- a/dlls/riched20/tests/editor.c
+++ b/dlls/riched20/tests/editor.c
@@ -535,6 +535,31 @@ static void test_EM_LINELENGTH(void)
         offset_test[i][0], result, offset_test[i][1]);
   }
 
+  /* EM_LINELENGTH with wParam == -1 returns the count of unselected
+   * characters on the line(s) containing the selection. */
+  SendMessageA(hwndRichEdit, EM_SETSEL, 0, 0);
+  result = SendMessageA(hwndRichEdit, EM_LINELENGTH, -1, 0);
+  ok(result == 9, "EM_LINELENGTH(-1) with caret at start: got %Id, expected 9\n", result);
+
+  SendMessageA(hwndRichEdit, EM_SETSEL, 5, 5);
+  result = SendMessageA(hwndRichEdit, EM_LINELENGTH, -1, 0);
+  ok(result == 9, "EM_LINELENGTH(-1) with caret mid-line: got %Id, expected 9\n", result);
+
+  /* Selection entirely within one line: unselected chars on that line */
+  SendMessageA(hwndRichEdit, EM_SETSEL, 2, 5);
+  result = SendMessageA(hwndRichEdit, EM_LINELENGTH, -1, 0);
+  ok(result == 6, "EM_LINELENGTH(-1) with sel 2..5 on line 1: got %Id, expected 6\n", result);
+
+  /* Selection spanning two lines: unselected chars on first + last line */
+  SendMessageA(hwndRichEdit, EM_SETSEL, 4, 13);
+  result = SendMessageA(hwndRichEdit, EM_LINELENGTH, -1, 0);
+  ok(result == 10, "EM_LINELENGTH(-1) with sel 4..13: got %Id, expected 10\n", result);
+
+  /* Caret at end of text */
+  SendMessageA(hwndRichEdit, EM_SETSEL, 39, 39);
+  result = SendMessageA(hwndRichEdit, EM_LINELENGTH, -1, 0);
+  ok(result == 9, "EM_LINELENGTH(-1) with caret at end: got %Id, expected 9\n", result);
+
   /* Test with multibyte character */
   if (!is_lang_japanese)
     skip("Skip multibyte character tests on non-Japanese platform\n");
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10888

[Rose Hellsing (＠axtlos)]

On Thu May 14 11:50:17 2026 +0000, Huw Davies wrote:
> Could we have a test for this please?  There are already `EM_LINELENGTH`
> tests in `test_EM_LINELENGTH()`.
> Expanded `test_EM_LINELENGTH()` with some basic cases for `wParam=-1`, hope these are okay!

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10888#note_139811

[PATCH v2 0/2] MR10888: riched20: Implement EM_LINELENGTH with wParam==-1 - approved

[Huw Davies (＠huw)]

This merge request was approved by Huw Davies.
-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10888