winrt: properly retrieve font writing systems from unicode ranges

This was completely broken until now because the ranges were assumed to be
from the OS/2 header map. These are actual unicode ranges from the cmap,
so they need to be matched by looping over the values and checking if they
fall within a given writing system range.

Task-number: QTBUG-44155
Done-with: Peng Wu <peng.wu@intopalo.com>
Change-Id: I933429627c4dbf3377f41c9281df5a801057698f
Reviewed-by: Oliver Wolff <oliver.wolff@theqtcompany.com>

1 files changed, 82 insertions, 7 deletions

diff --git a/src/plugins/platforms/winrt/qwinrtfontdatabase.cpp b/src/plugins/platforms/winrt/qwinrtfontdatabase.cpp
index 15767c2805..8a3205220b 100644
--- a/src/plugins/platforms/winrt/qwinrtfontdatabase.cpp
+++ b/src/plugins/platforms/winrt/qwinrtfontdatabase.cpp
@@ -46,6 +46,71 @@ using namespace Microsoft::WRL;
 
 QT_BEGIN_NAMESPACE
 
+// Based on unicode range tables at http://www.microsoft.com/typography/otspec/os2.htm#ur
+static QFontDatabase::WritingSystem writingSystemFromUnicodeRange(const DWRITE_UNICODE_RANGE &range)
+{
+    if (range.first >= 0x0000 && range.last <= 0x007F)
+        return QFontDatabase::Latin;
+    if (range.first >= 0x0370 && range.last <= 0x03FF)
+        return QFontDatabase::Greek;
+    if (range.first >= 0x0400 && range.last <= 0x04FF)
+        return QFontDatabase::Cyrillic;
+    if (range.first >= 0x0530 && range.last <= 0x058F)
+        return QFontDatabase::Armenian;
+    if (range.first >= 0x0590 && range.last <= 0x05FF)
+        return QFontDatabase::Hebrew;
+    if (range.first >= 0x0600 && range.last <= 0x06FF)
+        return QFontDatabase::Arabic;
+    if (range.first >= 0x0700 && range.last <= 0x074F)
+        return QFontDatabase::Syriac;
+    if (range.first >= 0x0780 && range.last <= 0x07BF)
+        return QFontDatabase::Thaana;
+    if (range.first >= 0x0900 && range.last <= 0x097F)
+        return QFontDatabase::Devanagari;
+    if (range.first >= 0x0980 && range.last <= 0x09FF)
+        return QFontDatabase::Bengali;
+    if (range.first >= 0x0A00 && range.last <= 0x0A7F)
+        return QFontDatabase::Gurmukhi;
+    if (range.first >= 0x0A80 && range.last <= 0x0AFF)
+        return QFontDatabase::Gujarati;
+    if (range.first >= 0x0B00 && range.last <= 0x0B7F)
+        return QFontDatabase::Oriya;
+    if (range.first >= 0x0B80 && range.last <= 0x0BFF)
+        return QFontDatabase::Tamil;
+    if (range.first >= 0x0C00 && range.last <= 0x0C7F)
+        return QFontDatabase::Telugu;
+    if (range.first >= 0x0C80 && range.last <= 0x0CFF)
+        return QFontDatabase::Kannada;
+    if (range.first >= 0x0D00 && range.last <= 0x0D7F)
+        return QFontDatabase::Malayalam;
+    if (range.first >= 0x0D80 && range.last <= 0x0DFF)
+        return QFontDatabase::Sinhala;
+    if (range.first >= 0x0E00 && range.last <= 0x0E7F)
+        return QFontDatabase::Thai;
+    if (range.first >= 0x0E80 && range.last <= 0x0EFF)
+        return QFontDatabase::Lao;
+    if (range.first >= 0x0F00 && range.last <= 0x0FFF)
+        return QFontDatabase::Tibetan;
+    if (range.first >= 0x1000 && range.last <= 0x109F)
+        return QFontDatabase::Myanmar;
+    if (range.first >= 0x10A0 && range.last <= 0x10FF)
+        return QFontDatabase::Georgian;
+    if (range.first >= 0x1780 && range.last <= 0x17FF)
+        return QFontDatabase::Khmer;
+    if (range.first >= 0x4E00 && range.last <= 0x9FFF)
+        return QFontDatabase::SimplifiedChinese;
+    if (range.first >= 0xAC00 && range.last <= 0xD7AF)
+        return QFontDatabase::Korean;
+    if (range.first >= 0x1680 && range.last <= 0x169F)
+        return QFontDatabase::Ogham;
+    if (range.first >= 0x16A0 && range.last <= 0x16FF)
+        return QFontDatabase::Runic;
+    if (range.first >= 0x07C0 && range.last <= 0x07FF)
+        return QFontDatabase::Nko;
+
+    return QFontDatabase::Other;
+}
+
 QString QWinRTFontDatabase::fontDir() const
 {
     QString fontDirectory = QBasicFontDatabase::fontDir();
@@ -260,17 +325,27 @@ void QWinRTFontDatabase::populateFamily(const QString &familyName)
 
         const bool fixedPitch = fontFace->IsMonospacedFont();
 
-        quint32 unicodeRange[4];
+        // Get writing systems from unicode ranges
         quint32 actualRangeCount;
-        hr = fontFace->GetUnicodeRanges(
-                    2, reinterpret_cast<DWRITE_UNICODE_RANGE *>(unicodeRange), &actualRangeCount);
-        if (FAILED(hr) && hr != E_NOT_SUFFICIENT_BUFFER) { // Ignore insufficient buffer; we only need 4 indices
+        hr = fontFace->GetUnicodeRanges(0, nullptr, &actualRangeCount);
+        Q_ASSERT(hr == E_NOT_SUFFICIENT_BUFFER);
+        QVector<DWRITE_UNICODE_RANGE> unicodeRanges(actualRangeCount);
+        hr = fontFace->GetUnicodeRanges(actualRangeCount, unicodeRanges.data(), &actualRangeCount);
+        if (FAILED(hr)) {
             qWarning("Unable to get font unicode range: %s", qPrintable(qt_error_string(hr)));
             continue;
         }
-        quint32 codePageRange[2] = { 0, 0 };
-        QSupportedWritingSystems writingSystems =
-                QPlatformFontDatabase::writingSystemsFromTrueTypeBits(unicodeRange, codePageRange);
+        QSupportedWritingSystems writingSystems;
+        for (quint32 i = 0; i < actualRangeCount; ++i) {
+            const QFontDatabase::WritingSystem writingSystem = writingSystemFromUnicodeRange(unicodeRanges.at(i));
+            writingSystems.setSupported(writingSystem);
+        }
+        if (writingSystems.supported(QFontDatabase::SimplifiedChinese)) {
+            writingSystems.setSupported(QFontDatabase::TraditionalChinese);
+            writingSystems.setSupported(QFontDatabase::Japanese);
+        }
+        if (writingSystems.supported(QFontDatabase::Latin))
+            writingSystems.setSupported(QFontDatabase::Vietnamese);
 
         IDWriteFontFile *fontFile;
         hr = fontFace->GetFiles(&fileCount, &fontFile);