Do not use charset loaded by fontconfig

The only use for storing charset loaded by fontconfig in font engines
is for determine if a font supports certain codepoint, however FreeType
already does that. The charset loaded is sometimes not complete, for
instance in fontconfig 2.9.0 it removed Apple Roman platform support
for cmap loading, thus results a regression in common symbol fonts
(Wingdings, Webdings) rendering. Because those symbol fonts produced
by Monotype only contain two cmap tables: Apple Roman and Microsoft
Symbol, since the Microsoft Symbol table has a weird 0xF000 offset,
we always fallback to the Apple Roman cmap table.

Removing freetype charset cache also make each font engine consuming
less memory.

Change-Id: I88f3f44981f3a1c517b84809a3f5b834ffff7681
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

2 files changed, 13 insertions, 53 deletions

diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index 6bcc3216f5..ac9dd99660 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -270,9 +270,6 @@ QFreetypeFace *QFreetypeFace::getFace(const QFontEngine::FaceId &face_id,
         newFreetype->matrix.yx = 0;
         newFreetype->unicode_map = 0;
         newFreetype->symbol_map = 0;
-#ifndef QT_NO_FONTCONFIG
-        newFreetype->charset = 0;
-#endif
 
         memset(newFreetype->cmapCache, 0, sizeof(newFreetype->cmapCache));
 
@@ -299,21 +296,6 @@ QFreetypeFace *QFreetypeFace::getFace(const QFontEngine::FaceId &face_id,
 
         if (!FT_IS_SCALABLE(newFreetype->face) && newFreetype->face->num_fixed_sizes == 1)
             FT_Set_Char_Size (face, X_SIZE(newFreetype->face, 0), Y_SIZE(newFreetype->face, 0), 0, 0);
-# if 0
-        FcChar8 *name;
-        FcPatternGetString(pattern, FC_FAMILY, 0, &name);
-        qDebug("%s: using maps: default: %x unicode: %x, symbol: %x", name,
-               newFreetype->face->charmap ? newFreetype->face->charmap->encoding : 0,
-               newFreetype->unicode_map ? newFreetype->unicode_map->encoding : 0,
-               newFreetype->symbol_map ? newFreetype->symbol_map->encoding : 0);
-
-        for (int i = 0; i < 256; i += 8)
-            qDebug("    %x: %d %d %d %d %d %d %d %d", i,
-                   FcCharSetHasChar(newFreetype->charset, i), FcCharSetHasChar(newFreetype->charset, i),
-                   FcCharSetHasChar(newFreetype->charset, i), FcCharSetHasChar(newFreetype->charset, i),
-                   FcCharSetHasChar(newFreetype->charset, i), FcCharSetHasChar(newFreetype->charset, i),
-                   FcCharSetHasChar(newFreetype->charset, i), FcCharSetHasChar(newFreetype->charset, i));
-#endif
 
         FT_Set_Charmap(newFreetype->face, newFreetype->unicode_map);
         QT_TRY {
@@ -334,10 +316,6 @@ void QFreetypeFace::release(const QFontEngine::FaceId &face_id)
     if (!ref.deref()) {
         qHBFreeFace(hbFace);
         FT_Done_Face(face);
-#ifndef QT_NO_FONTCONFIG
-        if (charset)
-            FcCharSetDestroy(charset);
-#endif
         if(freetypeData->faces.contains(face_id))
             freetypeData->faces.take(face_id);
         delete this;
@@ -1430,19 +1408,6 @@ static inline unsigned int getChar(const QChar *str, int &i, const int len)
 bool QFontEngineFT::canRender(const QChar *string, int len)
 {
     FT_Face face = freetype->face;
-#if 0
-    if (_cmap != -1) {
-        lockFace();
-        for ( int i = 0; i < len; i++ ) {
-            unsigned int uc = getChar(string, i, len);
-            if (!FcCharSetHasChar (_font->charset, uc) && getAdobeCharIndex(face, _cmap, uc) == 0) {
-                allExist = false;
-                break;
-            }
-        }
-        unlockFace();
-    } else
-#endif
     {
         for ( int i = 0; i < len; i++ ) {
             unsigned int uc = getChar(string, i, len);
@@ -1513,19 +1478,20 @@ bool QFontEngineFT::stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs
             unsigned int uc = getChar(str, i, len);
             glyphs->glyphs[glyph_pos] = uc < QFreetypeFace::cmapCacheSize ? freetype->cmapCache[uc] : 0;
             if ( !glyphs->glyphs[glyph_pos] ) {
-                glyph_t glyph;
-#if !defined(QT_NO_FONTCONFIG)
-                if (freetype->charset != 0 && FcCharSetHasChar(freetype->charset, uc)) {
-#else
-                if (false) {
-#endif
-                redo0:
+                // Symbol fonts can have more than one CMAPs, FreeType should take the
+                // correct one for us by default, so we always try FT_Get_Char_Index
+                // first. If it didn't work (returns 0), we will explicitly set the
+                // CMAP to symbol font one and try again. symbol_map is not always the
+                // correct one because in certain fonts like Wingdings symbol_map only
+                // contains PUA codepoints instead of the common ones.
+                glyph_t glyph = FT_Get_Char_Index(face, uc);
+                // Certain symbol fonts don't have no-break space (0xa0) and tab (0x9),
+                // while we usually want to render them as space
+                if (!glyph && (uc == 0xa0 || uc == 0x9)) {
+                    uc = 0x20;
                     glyph = FT_Get_Char_Index(face, uc);
-                    if (!glyph && (uc == 0xa0 || uc == 0x9)) {
-                        uc = 0x20;
-                        goto redo0;
-                    }
-                } else {
+                }
+                if (!glyph) {
                     FT_Set_Charmap(face, freetype->symbol_map);
                     glyph = FT_Get_Char_Index(face, uc);
                     FT_Set_Charmap(face, freetype->unicode_map);
@@ -1544,9 +1510,6 @@ bool QFontEngineFT::stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs
                 uc = QChar::mirroredChar(uc);
             glyphs->glyphs[glyph_pos] = uc < QFreetypeFace::cmapCacheSize ? freetype->cmapCache[uc] : 0;
             if (!glyphs->glyphs[glyph_pos]) {
-#if !defined(QT_NO_FONTCONFIG)
-                if (freetype->charset == 0 || FcCharSetHasChar(freetype->charset, uc))
-#endif
                 {
                 redo:
                     glyph_t glyph = FT_Get_Char_Index(face, uc);
diff --git a/src/gui/text/qfontengine_ft_p.h b/src/gui/text/qfontengine_ft_p.h
index 77939120f8..e665ce8a09 100644
--- a/src/gui/text/qfontengine_ft_p.h
+++ b/src/gui/text/qfontengine_ft_p.h
@@ -102,9 +102,6 @@ struct QFreetypeFace
 
     FT_Face face;
     HB_Face hbFace;
-#ifndef QT_NO_FONTCONFIG
-    FcCharSet *charset;
-#endif
     int xsize; // 26.6
     int ysize; // 26.6
     FT_Matrix matrix;