Nikolay Sivov : dwrite: Handle fonts with broken usWinDescent values.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 5cb954aa6aa60464a364b645227a3d00d2295740
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=5cb954aa6aa60464a364b64522...

Author: Nikolay Sivov <nsivov(a)codeweavers.com>
Date:   Sun Sep 27 22:53:42 2015 +0300

dwrite: Handle fonts with broken usWinDescent values.

---

 dlls/dwrite/opentype.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dlls/dwrite/opentype.c b/dlls/dwrite/opentype.c
index fd471ef..82e0a9c 100644
--- a/dlls/dwrite/opentype.c
+++ b/dlls/dwrite/opentype.c
@@ -960,7 +960,9 @@ void opentype_get_font_metrics(IDWriteFontFileStream *stream, DWRITE_FONT_FACE_T
         USHORT version = GET_BE_WORD(tt_os2->version);
 
         metrics->ascent  = GET_BE_WORD(tt_os2->usWinAscent);
-        metrics->descent = GET_BE_WORD(tt_os2->usWinDescent);
+        /* Some fonts have usWinDescent value stored as signed short, which could be wrongly
+           interpreted as large unsigned value. */
+        metrics->descent = abs((SHORT)GET_BE_WORD(tt_os2->usWinDescent));
 
         /* line gap is estimated using two sets of ascender/descender values and 'hhea' line gap */
         if (tt_hhea) {