std::string FontRendererImpl::GetFontKey(ComPtr<IDWriteFontFace> fontFace, float emSize)
{
// get the file reference key
uint32_t reqFiles = 1;
IDWriteFontFile* file;
fontFace->GetFiles(&reqFiles, &file);
const void* referenceKey;
uint32_t referenceKeySize;
file->GetReferenceKey(&referenceKey, &referenceKeySize);
// store in a buffer and append the size
uint32_t referenceKeySizeTarget = min(referenceKeySize, 128);
char refKeyBuffer[256];
memcpy(refKeyBuffer, referenceKey, referenceKeySizeTarget);
*(float*)&refKeyBuffer[referenceKeySizeTarget] = emSize;
// release the file
file->Release();
return std::string(refKeyBuffer, referenceKeySizeTarget + 4);
}
QFontEngine *QWinRTFontDatabase::fontEngine(const QFontDef &fontDef, void *handle)
{
if (!handle) // Happens if a font family population failed
return 0;
IDWriteFontFile *fontFile = reinterpret_cast<IDWriteFontFile *>(handle);
if (!m_fonts.contains(fontFile))
return QBasicFontDatabase::fontEngine(fontDef, handle);
const void *referenceKey;
quint32 referenceKeySize;
HRESULT hr = fontFile->GetReferenceKey(&referenceKey, &referenceKeySize);
if (FAILED(hr)) {
qWarning("Unable to get font file reference key: %s", qPrintable(qt_error_string(hr)));
return 0;
}
ComPtr<IDWriteFontFileLoader> loader;
hr = fontFile->GetLoader(&loader);
if (FAILED(hr)) {
qWarning("Unable to get font file loader: %s", qPrintable(qt_error_string(hr)));
return 0;
}
ComPtr<IDWriteFontFileStream> stream;
hr =loader->CreateStreamFromKey(referenceKey, referenceKeySize, &stream);
if (FAILED(hr)) {
qWarning("Unable to get font file stream: %s", qPrintable(qt_error_string(hr)));
return 0;
}
quint64 fileSize;
hr = stream->GetFileSize(&fileSize);
if (FAILED(hr)) {
qWarning("Unable to get font file size: %s", qPrintable(qt_error_string(hr)));
return 0;
}
const void *data;
void *context;
hr = stream->ReadFileFragment(&data, 0, fileSize, &context);
if (FAILED(hr)) {
qWarning("Unable to get font file data: %s", qPrintable(qt_error_string(hr)));
return 0;
}
const QByteArray fontData((const char *)data, fileSize);
stream->ReleaseFileFragment(context);
QFontEngine::FaceId faceId;
const FontDescription description = m_fonts.value(fontFile);
faceId.uuid = description.uuid;
faceId.index = description.index;
const bool antialias = !(fontDef.styleStrategy & QFont::NoAntialias);
QFontEngineFT::GlyphFormat format = antialias ? QFontEngineFT::Format_A8 : QFontEngineFT::Format_Mono;
QFontEngineFT *engine = new QFontEngineFT(fontDef);
if (!engine->init(faceId, antialias, format, fontData) || engine->invalid()) {
delete engine;
return 0;
}
return engine;
}