DirectWrite font db: Fix fallback fonts

The implementation of this was based on a misunderstanding of the API. The
GetMatchingFonts() function does not give a sorted list of fonts that
can be used in place of the given family, but just requests the fonts in
the family itself.

Instead, we use the same implementation as in the other two font databases
we have on Windows (moving the implementation to be shared).

Change-Id: I6a7b73e3d8376f7d97f598db0d7b63122ad1940c
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

6 files changed, 135 insertions, 174 deletions

diff --git a/src/platformsupport/fontdatabases/windows/qwindowsdirectwritefontdatabase.cpp b/src/platformsupport/fontdatabases/windows/qwindowsdirectwritefontdatabase.cpp
index a0483c2413..e2a9dbdedd 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsdirectwritefontdatabase.cpp
+++ b/src/platformsupport/fontdatabases/windows/qwindowsdirectwritefontdatabase.cpp
@@ -39,6 +39,7 @@
 
 #include "qwindowsdirectwritefontdatabase_p.h"
 #include "qwindowsfontenginedirectwrite_p.h"
+#include "qwindowsfontdatabase_p.h"
 
 #include <QtCore/qendian.h>
 #include <QtCore/qstringbuilder.h>
@@ -269,54 +270,14 @@ QFontEngine *QWindowsDirectWriteFontDatabase::fontEngine(const QFontDef &fontDef
 
 QStringList QWindowsDirectWriteFontDatabase::fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script) const
 {
-    Q_UNUSED(styleHint);
-    Q_UNUSED(script);
-
-    wchar_t defaultLocale[LOCALE_NAME_MAX_LENGTH];
-    bool hasDefaultLocale = GetUserDefaultLocaleName(defaultLocale, LOCALE_NAME_MAX_LENGTH) != 0;
-    wchar_t englishLocale[] = L"en-us";
-
-    QStringList ret;
-
-    auto it = m_populatedFonts.find(family);
-    IDWriteFontFamily *fontFamily = it != m_populatedFonts.end() ? it.value() : nullptr;
-    if (fontFamily != nullptr) {
-        IDWriteFontList *matchingFonts = nullptr;
-        if (SUCCEEDED(fontFamily->GetMatchingFonts(DWRITE_FONT_WEIGHT_REGULAR,
-                                                   DWRITE_FONT_STRETCH_NORMAL,
-                                                   toDirectWriteStyle(style),
-                                                   &matchingFonts))) {
-            for (uint j = 0; j < matchingFonts->GetFontCount(); ++j) {
-                IDWriteFont *font = nullptr;
-                if (SUCCEEDED(matchingFonts->GetFont(j, &font))) {
-                    IDWriteFontFamily *fontFamily2;
-                    if (SUCCEEDED(font->GetFontFamily(&fontFamily2))) {
-                        IDWriteLocalizedStrings *names;
-                        if (SUCCEEDED(fontFamily2->GetFamilyNames(&names))) {
-                            QString name = localeString(names, englishLocale);
-                            if (name.isEmpty() && hasDefaultLocale)
-                                name = localeString(names, defaultLocale);
-
-                            if (!name.isEmpty() && m_populatedFonts.contains(name))
-                                ret.append(name);
-
-                            names->Release();
-                        }
-
-                        fontFamily2->Release();
-                    }
-
-                    font->Release();
-                }
-            }
-
-            matchingFonts->Release();
-        }
-    }
-
-    qDebug(lcQpaFonts) << "fallbacks for" << family << "is" << ret;
-
-    return ret;
+    QStringList result;
+    result.append(familyForStyleHint(styleHint));
+    result.append(extraTryFontsForFamily(family));
+    result.append(QPlatformFontDatabase::fallbacksForFamily(family, style, styleHint, script));
+
+    qCDebug(lcQpaFonts) << __FUNCTION__ << family << style << styleHint
+        << script << result;
+    return result;
 }
 
 QStringList QWindowsDirectWriteFontDatabase::addApplicationFont(const QByteArray &fontData, const QString &fileName)
diff --git a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase.cpp b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase.cpp
index cf5763fdbe..9c348c9e19 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase.cpp
+++ b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase.cpp
@@ -1080,131 +1080,12 @@ void QWindowsFontDatabase::refUniqueFont(const QString &uniqueFont)
         m_uniqueFontData[uniqueFont].refCount.ref();
 }
 
-// Creation functions
-
-static const char *other_tryFonts[] = {
-    "Arial",
-    "MS UI Gothic",
-    "Gulim",
-    "SimSun",
-    "PMingLiU",
-    "Arial Unicode MS",
-    0
-};
-
-static const char *jp_tryFonts [] = {
-    "MS UI Gothic",
-    "Arial",
-    "Gulim",
-    "SimSun",
-    "PMingLiU",
-    "Arial Unicode MS",
-    0
-};
-
-static const char *ch_CN_tryFonts [] = {
-    "SimSun",
-    "Arial",
-    "PMingLiU",
-    "Gulim",
-    "MS UI Gothic",
-    "Arial Unicode MS",
-    0
-};
-
-static const char *ch_TW_tryFonts [] = {
-    "PMingLiU",
-    "Arial",
-    "SimSun",
-    "Gulim",
-    "MS UI Gothic",
-    "Arial Unicode MS",
-    0
-};
-
-static const char *kr_tryFonts[] = {
-    "Gulim",
-    "Arial",
-    "PMingLiU",
-    "SimSun",
-    "MS UI Gothic",
-    "Arial Unicode MS",
-    0
-};
-
-static const char **tryFonts = 0;
-
-QStringList QWindowsFontDatabase::extraTryFontsForFamily(const QString &family)
-{
-    QStringList result;
-    QFontDatabase db;
-    if (!db.writingSystems(family).contains(QFontDatabase::Symbol)) {
-        if (!tryFonts) {
-            LANGID lid = GetUserDefaultLangID();
-            switch (lid&0xff) {
-            case LANG_CHINESE: // Chinese
-                if ( lid == 0x0804 || lid == 0x1004) // China mainland and Singapore
-                    tryFonts = ch_CN_tryFonts;
-                else
-                    tryFonts = ch_TW_tryFonts; // Taiwan, Hong Kong and Macau
-                break;
-            case LANG_JAPANESE:
-                tryFonts = jp_tryFonts;
-                break;
-            case LANG_KOREAN:
-                tryFonts = kr_tryFonts;
-                break;
-            default:
-                tryFonts = other_tryFonts;
-                break;
-            }
-        }
-        QFontDatabase db;
-        const QStringList families = db.families();
-        const char **tf = tryFonts;
-        while (tf && *tf) {
-            // QTBUG-31689, family might be an English alias for a localized font name.
-            const QString family = QString::fromLatin1(*tf);
-            if (families.contains(family) || db.hasFamily(family))
-                result << family;
-            ++tf;
-        }
-    }
-    result.append(QStringLiteral("Segoe UI Emoji"));
-    result.append(QStringLiteral("Segoe UI Symbol"));
-    return result;
-}
-
-QString QWindowsFontDatabase::familyForStyleHint(QFont::StyleHint styleHint)
-{
-    switch (styleHint) {
-    case QFont::Times:
-        return QStringLiteral("Times New Roman");
-    case QFont::Courier:
-        return QStringLiteral("Courier New");
-    case QFont::Monospace:
-        return QStringLiteral("Courier New");
-    case QFont::Cursive:
-        return QStringLiteral("Comic Sans MS");
-    case QFont::Fantasy:
-        return QStringLiteral("Impact");
-    case QFont::Decorative:
-        return QStringLiteral("Old English");
-    case QFont::Helvetica:
-        return QStringLiteral("Arial");
-    case QFont::System:
-    default:
-        break;
-    }
-    return QStringLiteral("MS Shell Dlg 2");
-}
-
 QStringList QWindowsFontDatabase::fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script) const
 {
     QStringList result;
-    result.append(QWindowsFontDatabase::familyForStyleHint(styleHint));
+    result.append(familyForStyleHint(styleHint));
     result.append(m_eudcFonts);
-    result.append(QWindowsFontDatabase::extraTryFontsForFamily(family));
+    result.append(extraTryFontsForFamily(family));
     result.append(QPlatformFontDatabase::fallbacksForFamily(family, style, styleHint, script));
 
     qCDebug(lcQpaFonts) << __FUNCTION__ << family << style << styleHint
diff --git a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_ft.cpp b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_ft.cpp
index 5c2742d295..b355001254 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_ft.cpp
+++ b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_ft.cpp
@@ -422,8 +422,8 @@ QFontEngine *QWindowsFontDatabaseFT::fontEngine(const QByteArray &fontData, qrea
 QStringList QWindowsFontDatabaseFT::fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script) const
 {
     QStringList result;
-    result.append(QWindowsFontDatabase::familyForStyleHint(styleHint));
-    result.append(QWindowsFontDatabase::extraTryFontsForFamily(family));
+    result.append(QWindowsFontDatabaseBase::familyForStyleHint(styleHint));
+    result.append(QWindowsFontDatabaseBase::extraTryFontsForFamily(family));
     result.append(QFreeTypeFontDatabase::fallbacksForFamily(family, style, styleHint, script));
 
     qCDebug(lcQpaFonts) << __FUNCTION__ << family << style << styleHint
diff --git a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_p.h b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_p.h
index a76fdc0810..64b80ed5b3 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_p.h
+++ b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabase_p.h
@@ -96,9 +96,6 @@ public:
 
     static qreal fontSmoothingGamma();
 
-    static QStringList extraTryFontsForFamily(const QString &family);
-    static QString familyForStyleHint(QFont::StyleHint styleHint);
-
     static void setFontOptions(unsigned options);
     static unsigned fontOptions();
 
diff --git a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase.cpp b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase.cpp
index 5b8707cdec..e6dee54d84 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase.cpp
+++ b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase.cpp
@@ -866,4 +866,123 @@ QFontEngine *QWindowsFontDatabaseBase::fontEngine(const QByteArray &fontData, qr
     return fontEngine;
 }
 
+QString QWindowsFontDatabaseBase::familyForStyleHint(QFont::StyleHint styleHint)
+{
+    switch (styleHint) {
+    case QFont::Times:
+        return QStringLiteral("Times New Roman");
+    case QFont::Courier:
+        return QStringLiteral("Courier New");
+    case QFont::Monospace:
+        return QStringLiteral("Courier New");
+    case QFont::Cursive:
+        return QStringLiteral("Comic Sans MS");
+    case QFont::Fantasy:
+        return QStringLiteral("Impact");
+    case QFont::Decorative:
+        return QStringLiteral("Old English");
+    case QFont::Helvetica:
+        return QStringLiteral("Arial");
+    case QFont::System:
+    default:
+        break;
+    }
+    return QStringLiteral("MS Shell Dlg 2");
+}
+
+// Creation functions
+
+static const char *other_tryFonts[] = {
+    "Arial",
+    "MS UI Gothic",
+    "Gulim",
+    "SimSun",
+    "PMingLiU",
+    "Arial Unicode MS",
+    0
+};
+
+static const char *jp_tryFonts [] = {
+    "MS UI Gothic",
+    "Arial",
+    "Gulim",
+    "SimSun",
+    "PMingLiU",
+    "Arial Unicode MS",
+    0
+};
+
+static const char *ch_CN_tryFonts [] = {
+    "SimSun",
+    "Arial",
+    "PMingLiU",
+    "Gulim",
+    "MS UI Gothic",
+    "Arial Unicode MS",
+    0
+};
+
+static const char *ch_TW_tryFonts [] = {
+    "PMingLiU",
+    "Arial",
+    "SimSun",
+    "Gulim",
+    "MS UI Gothic",
+    "Arial Unicode MS",
+    0
+};
+
+static const char *kr_tryFonts[] = {
+    "Gulim",
+    "Arial",
+    "PMingLiU",
+    "SimSun",
+    "MS UI Gothic",
+    "Arial Unicode MS",
+    0
+};
+
+static const char **tryFonts = nullptr;
+
+QStringList QWindowsFontDatabaseBase::extraTryFontsForFamily(const QString &family)
+{
+    QStringList result;
+    QFontDatabase db;
+    if (!db.writingSystems(family).contains(QFontDatabase::Symbol)) {
+        if (!tryFonts) {
+            LANGID lid = GetUserDefaultLangID();
+            switch (lid&0xff) {
+            case LANG_CHINESE: // Chinese
+                if ( lid == 0x0804 || lid == 0x1004) // China mainland and Singapore
+                    tryFonts = ch_CN_tryFonts;
+                else
+                    tryFonts = ch_TW_tryFonts; // Taiwan, Hong Kong and Macau
+                break;
+            case LANG_JAPANESE:
+                tryFonts = jp_tryFonts;
+                break;
+            case LANG_KOREAN:
+                tryFonts = kr_tryFonts;
+                break;
+            default:
+                tryFonts = other_tryFonts;
+                break;
+            }
+        }
+        QFontDatabase db;
+        const QStringList families = db.families();
+        const char **tf = tryFonts;
+        while (tf && *tf) {
+            // QTBUG-31689, family might be an English alias for a localized font name.
+            const QString family = QString::fromLatin1(*tf);
+            if (families.contains(family) || db.hasFamily(family))
+                result << family;
+            ++tf;
+        }
+    }
+    result.append(QStringLiteral("Segoe UI Emoji"));
+    result.append(QStringLiteral("Segoe UI Symbol"));
+    return result;
+}
+
 QT_END_NAMESPACE
diff --git a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase_p.h b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase_p.h
index fbaa98b663..5b9db5dede 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase_p.h
+++ b/src/platformsupport/fontdatabases/windows/qwindowsfontdatabasebase_p.h
@@ -102,6 +102,9 @@ public:
     static LOGFONT fontDefToLOGFONT(const QFontDef &fontDef, const QString &faceName);
     static QFont LOGFONT_to_QFont(const LOGFONT& lf, int verticalDPI = 0);
 
+    static QString familyForStyleHint(QFont::StyleHint styleHint);
+    static QStringList extraTryFontsForFamily(const QString &family);
+
     class FontTable{};
     class EmbeddedFont
     {