uiLengthDrawn should represent the number of characters that have been processed. However, the original implementation uses len (the count of displayed characters in the current line), which is not accurate.
When text requires line breaks or special processing (such as adding an ellipsis), the actual number of processed characters may differ from the number of displayed characters.
When the DT_CALCRECT flag is absent, len gets decremented to 0 during the drawing loop.
Consequently, uiLengthDrawn becomes inaccurate since it relies on len's value for statistics.
-- v7: user32: Fix uiLengthDrawn calculation in DrawTextExW().
From: chenjiangyi chenjiangyi@uniontech.com
--- dlls/user32/tests/text.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/dlls/user32/tests/text.c b/dlls/user32/tests/text.c index d3228eae1e0..ea2ef98a2dd 100644 --- a/dlls/user32/tests/text.c +++ b/dlls/user32/tests/text.c @@ -656,6 +656,35 @@ static void test_DrawTextCalcRect(void) ok(rect.top == rect2.top, "unexpected value %ld, got %ld\n", rect.top, rect2.top); ok(rect.bottom == rect2.bottom , "unexpected value %ld, got %ld\n", rect.bottom, rect2.bottom);
+ /* Test uiLengthDrawn calculation */ + SelectObject(hdc, hOldFont); + ret = DeleteObject(hFont); + ok(ret, "DeleteObject error %lu\n", GetLastError()); + lf.lfHeight = 200 * 9 / 72; + hFont = CreateFontIndirectA(&lf); + ok(hFont != 0, "CreateFontIndirectA error %lu\n", GetLastError()); + hOldFont = SelectObject(hdc, hFont); + + SetRect(&rect, 0, 0, 100, 25); + memset(&dtp, 0, sizeof(dtp)); + dtp.cbSize = sizeof(dtp); + textheight = DrawTextExW(hdc, textW, lstrlenW(textW), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK, &dtp); + todo_wine ok(dtp.uiLengthDrawn == 10, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn ); + + memset(&dtp, 0, sizeof(dtp)); + dtp.cbSize = sizeof(dtp); + textheight = DrawTextExW(hdc, textW, lstrlenW(textW), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK | DT_CALCRECT, &dtp); + todo_wine ok(dtp.uiLengthDrawn == 16, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn ); + + memset(&dtp, 0, sizeof(dtp)); + dtp.cbSize = sizeof(dtp); + textheight = DrawTextExW(hdc, (LPWSTR)L"a 1\tb2c3", lstrlenW(L"a 1\tb2c3"), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK, &dtp); + todo_wine ok(dtp.uiLengthDrawn == 8, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn ); + + memset(&dtp, 0, sizeof(dtp)); + dtp.cbSize = sizeof(dtp); + textheight = DrawTextExW(hdc, (LPWSTR)L"a 1\tb2c3", lstrlenW(L"a 1\tb2c3"), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK | DT_CALCRECT, &dtp); + ok(dtp.uiLengthDrawn == 8, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn );
SelectObject(hdc, hOldFont); ret = DeleteObject(hFont);
From: chenjiangyi chenjiangyi@uniontech.com
uiLengthDrawn should represent the number of characters that have been processed. However, the original implementation uses len (the count of displayed characters in the current line), which is not accurate.
When text requires line breaks or special processing (such as adding an ellipsis), the actual number of processed characters may differ from the number of displayed characters.
When the DT_CALCRECT flag is absent, len gets decremented to 0 during the drawing loop.
Consequently, uiLengthDrawn becomes inaccurate since it relies on len's value for statistics. --- dlls/user32/tests/text.c | 6 ++--- dlls/user32/text.c | 58 +++++++++++++++++++++------------------- 2 files changed, 33 insertions(+), 31 deletions(-)
diff --git a/dlls/user32/tests/text.c b/dlls/user32/tests/text.c index ea2ef98a2dd..31bb22bf234 100644 --- a/dlls/user32/tests/text.c +++ b/dlls/user32/tests/text.c @@ -669,17 +669,17 @@ static void test_DrawTextCalcRect(void) memset(&dtp, 0, sizeof(dtp)); dtp.cbSize = sizeof(dtp); textheight = DrawTextExW(hdc, textW, lstrlenW(textW), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK, &dtp); - todo_wine ok(dtp.uiLengthDrawn == 10, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn ); + ok(dtp.uiLengthDrawn == 10, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn );
memset(&dtp, 0, sizeof(dtp)); dtp.cbSize = sizeof(dtp); textheight = DrawTextExW(hdc, textW, lstrlenW(textW), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK | DT_CALCRECT, &dtp); - todo_wine ok(dtp.uiLengthDrawn == 16, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn ); + ok(dtp.uiLengthDrawn == 16, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn );
memset(&dtp, 0, sizeof(dtp)); dtp.cbSize = sizeof(dtp); textheight = DrawTextExW(hdc, (LPWSTR)L"a 1\tb2c3", lstrlenW(L"a 1\tb2c3"), &rect, DT_EDITCONTROL | DT_NOPREFIX | DT_WORDBREAK, &dtp); - todo_wine ok(dtp.uiLengthDrawn == 8, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn ); + ok(dtp.uiLengthDrawn == 8, "Unexpected uiLengthDrawn %d\n", dtp.uiLengthDrawn );
memset(&dtp, 0, sizeof(dtp)); dtp.cbSize = sizeof(dtp); diff --git a/dlls/user32/text.c b/dlls/user32/text.c index 1896627c893..5b747754f52 100644 --- a/dlls/user32/text.c +++ b/dlls/user32/text.c @@ -871,7 +871,7 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count, WCHAR *retstr; size_t size_retstr; WCHAR line[MAX_BUFFER]; - int len, lh, count=i_count; + int len, lh, old_count, count=i_count; TEXTMETRICW tm; int lmargin = 0, rmargin = 0; int x, y, width; @@ -974,26 +974,30 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count, do { len = ARRAY_SIZE(line); - if (invert_y) - last_line = !(flags & DT_NOCLIP) && y - ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) < rect->bottom; - else - last_line = !(flags & DT_NOCLIP) && y + ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) > rect->bottom; - strPtr = TEXT_NextLineW(hdc, strPtr, &count, line, &len, width, flags, &size, last_line, retstr, tabwidth, &prefix_offset, &ellip); + if (invert_y) + last_line = !(flags & DT_NOCLIP) && y - ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) < rect->bottom; + else + last_line = !(flags & DT_NOCLIP) && y + ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) > rect->bottom; + + old_count = count; + strPtr = TEXT_NextLineW(hdc, strPtr, &count, line, &len, width, flags, &size, last_line, retstr, tabwidth, &prefix_offset, &ellip); + if (dtp) + dtp->uiLengthDrawn += old_count - count;
if (flags & DT_CENTER) x = (rect->left + lmargin + rect->right - rmargin - size.cx) / 2; else if (flags & DT_RIGHT) x = rect->right - size.cx - rmargin;
- if (flags & DT_SINGLELINE) - { - if (flags & DT_VCENTER) y = rect->top + - (rect->bottom - rect->top) / 2 - size.cy / 2; - else if (flags & DT_BOTTOM) y = rect->bottom - size.cy; + if (flags & DT_SINGLELINE) + { + if (flags & DT_VCENTER) y = rect->top + + (rect->bottom - rect->top) / 2 - size.cy / 2; + else if (flags & DT_BOTTOM) y = rect->bottom - size.cy; }
- if (!(flags & DT_CALCRECT)) - { + if (!(flags & DT_CALCRECT)) + { const WCHAR *str = line; int xseg = x; while (len) @@ -1011,9 +1015,9 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count, len_seg = len;
if (!ExtTextOutW( hdc, xseg, y, - ((flags & DT_NOCLIP) ? 0 : ETO_CLIPPED) | - ((flags & DT_RTLREADING) ? ETO_RTLREADING : 0), - rect, str, len_seg, NULL )) + ((flags & DT_NOCLIP) ? 0 : ETO_CLIPPED) | + ((flags & DT_RTLREADING) ? ETO_RTLREADING : 0), + rect, str, len_seg, NULL )) goto done; if (prefix_offset != -1 && prefix_offset < len_seg) { @@ -1031,11 +1035,11 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count, if (prefix_offset < len_seg) { /* We have just drawn an underscore; we ought to - * figure out where the next one is. I am going - * to leave it for now until I have a better model - * for the line, which will make reprefixing easier. - * This is where ellip would be used. - */ + * figure out where the next one is. I am going + * to leave it for now until I have a better model + * for the line, which will make reprefixing easier. + * This is where ellip would be used. + */ prefix_offset = -1; } else @@ -1043,16 +1047,14 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count, } } } - } - else if (size.cx > max_width) - max_width = size.cx; + } + else if (size.cx > max_width) + max_width = size.cx;
if (invert_y) - y -= lh; + y -= lh; else - y += lh; - if (dtp) - dtp->uiLengthDrawn += len; + y += lh; } while (strPtr && !last_line);
On Sun Aug 10 06:07:15 2025 +0000, JiangYi Chen wrote:
changed this line in [version 3 of the diff](/wine/wine/-/merge_requests/8178/diffs?diff_id=199656&start_sha=8569bdd040564c69766c4e29709ef2a0990a9771#e8595f9b497b04f5fd87cfe62abe9540dccb42b7_984_984)
Place the implementation on the next line. Without using {} to wrap the code block for 'dtp->uiLengthDrawn += old_count - count;' the subsequent code suffers from misleading indentation issues. This causes the GCC compiler to emit a warning as shown in the pictures below. Therefore, I've made some adjustments to the code indentation.
Regardless, the code indentation within the DrawTextExW() function is indeed quite messy, making it inconvenient to read the code.  
On Fri Aug 8 09:27:01 2025 +0000, Zhiyi Zhang wrote:
Could you explain `200 * 9 / 72`?
This is not addressed.
Zhiyi Zhang (@zhiyi) commented about dlls/user32/text.c:
do { len = ARRAY_SIZE(line);
- if (invert_y)
last_line = !(flags & DT_NOCLIP) && y - ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) < rect->bottom;- else
last_line = !(flags & DT_NOCLIP) && y + ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) > rect->bottom;- strPtr = TEXT_NextLineW(hdc, strPtr, &count, line, &len, width, flags, &size, last_line, retstr, tabwidth, &prefix_offset, &ellip);
if (invert_y)last_line = !(flags & DT_NOCLIP) && y - ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) < rect->bottom;elselast_line = !(flags & DT_NOCLIP) && y + ((flags & DT_EDITCONTROL) ? 2*lh-1 : lh) > rect->bottom;
Please don't add white-space changes unrelated to this patch.
-
chenjiangyi -
JiangYi Chen (＠meshine)
-
Zhiyi Zhang (＠zhiyi)