[Bug 46947] Loxone Config :bold text is missing with builtin gdiplus

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=46947

David Kahurani  changed:

What    |Removed                     |Added
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--- Comment #10 from David Kahurani  ---
I believe this program is relying on a gdiplus bug.

Windows bug:

0024:trace:gdiplus:GdipCreateStringFormat (0, 0, 0115D080)
0024:trace:gdiplus:GdipCreateStringFormat <-- 0394D7B8
0024:trace:gdiplus:GdipSetStringFormatAlign (0394D7B8, 0)
0024:trace:gdiplus:GdipSetStringFormatLineAlign (0394D7B8, 1)
0024:trace:gdiplus:GdipSetStringFormatHotkeyPrefix (0394D7B8, 0)
0024:trace:gdiplus:GdipSetStringFormatTrimming (0394D7B8, 3)
0024:trace:gdiplus:GdipSetStringFormatFlags (0394D7B8, 3000)
0024:trace:gdiplus:GdipDrawString (039D7430, L"Kontakt", 7, 039D7340,
(3168.00,3079.00,1288.00,192.00), 0394D7B8, 039C6FC0)

From here we can see that FormatFlags are set to 0x3000 - which is
StringFormatFlagsLineLimit | StringFormatFlagsNoWrap.

From the documentation we can read that:

StringFormatFlagsLineLimit
Value: 0x00002000
Specifies that only entire lines are laid out in the layout rectangle. By
default, layout continues until the end of the text or until no more lines are
visible as a result of clipping, whichever comes first. The default settings
allow the last line to be partially obscured by a layout rectangle that is not
a whole multiple of the line height. To ensure that only whole lines are seen,
set this flag and be careful to provide a layout rectangle at least as tall as
the height of one line.

However, on testing, this seems to give varying results, at least with
GdipDrawString because for instance, the following code snippet does actually
draw some clipped text on the screen:

HDC hdc = GetDC(hwnd);
  const WCHAR to_draw[] = L"Spice";

Graphics graphics(hdc);
  StringFormat stringFormat;
  Font font(L"Arial", 48);
  RectF size;

stringFormat.SetAlignment(0);
  stringFormat.SetLineAlignment(1);
  stringFormat.SetHotkeyPrefix(0);
  stringFormat.SetFormatFlags(0x3000);

SolidBrush brush(Color::Black);

graphics.MeasureString(to_draw, 5, &font, PointF(300.f, 300.f), &size);
  size.Height = size.Height - 50;
  graphics.DrawString(to_draw, 5, &font, size, &stringFormat, &brush);

This is all while having the StringFormatFlagsLineLimit set in the flags which
dictates that clipped text shouldn't be rendered. Other than this example,
Windows seems to randomly show or not show text that shouldn't be rendered(as
dictated by StringFormatFlagsLineLimit). I have not been able to identify any
patterns in its behaviour. This I think is a bug.

Coming to our program as in this bug. The program calls GdipMeasureString on
strings before calling GdipDrawString on them. However, it can be observed that
even after calling GdipMeasureString, the program goes on to ignore the layout
rectangle height provided by GdipMeasureString and setting, instead, a constant
height of 192.0

0024:trace:gdiplus:GdipDrawString (039D7430, L"Kontakt", 7, 039D7340,
(3168.00,3079.00,1288.00,192.00), 0394D7B8, 039C6FC0)

0024:trace:gdiplus:GdipDrawString (07767388, L"Raum verlassen Kitchen _ Diner",
30, 077675A0, (10176.00,1831.00,1288.00,192.00), 03B44BE0, 03A9F9D0)

Now, the bold font has a size of 160 while the non-bold font has a size of 120.
It goes without saying that the non-bold font will fit in the layout rectangle
while the bold will not. With StringFormatFlagsLineLimit the text that doesn't
fit in the layout rectangle is not rendered and hence the bold text is missing.
This however works on windows, contrary to what the documentation says. It
however doesn't seem to work reliably making me think this is a bug.

This solution would probably be to relax the StringFormatFlagsLineLimit flag on
Wine.