如何从 windows OS 下载但尚未安装的字体文件中获取 IDWriteFont 对象

Question

您好，我正在使用 DWrite APIs 通过 DWrite APIs 获取系统字体元数据。我正在执行以下操作。

    HR(DWriteCreateFactory(
        DWRITE_FACTORY_TYPE_SHARED,
        __uuidof(IDWriteFactory),
        reinterpret_cast<IUnknown **>(&factory)));

    // Get the system font collection.
    IDWriteFontCollection *collection = NULL;
    HR(factory->GetSystemFontCollection(&collection, TRUE));

    // Get the number of font families in the collection.
    int familyCount = collection->GetFontFamilyCount();

    // track unique font Ids we've already added
    // using a set so we don't get any duplicates.
    for (int i = 0; i < familyCount; i++)
    {
        IDWriteFontFamily *family = NULL;

        // Get the font family.
        HR(collection->GetFontFamily(i, &family));
        int fontCount = family->GetFontCount();

        for (int j = 0; j < fontCount; j++)
        {
            IDWriteFont *font = NULL;
            HR(family->GetFont(j, &font));
            fontMetaDataPtr* result = resultFromFont(font);
        }
    }

这将给我所有已安装字体的信息。现在我需要获取我下载的新字体的信息，但是 DWrite 中没有 API，我可以在其中使用字体文件路径 ex 获取 IDWriteFont *font 对象。 "C:\Downloads\Fonts.ttf"

你能分享任何工作示例吗？

我尝试了以下代码，但它没有用，因为它看起来像是临时安装字体而不是更新集合。

int result = AddFontResourceW(wideFontFilePath.c_str());
if (result > 0) {
    IDWriteFactory *factory = NULL;
    HR(DWriteCreateFactory(
    DWRITE_FACTORY_TYPE_SHARED,
    __uuidof(IDWriteFactory),
    reinterpret_cast<IUnknown **>(&factory)));

    // Get the system font collection.
    IDWriteFontCollection *collection = NULL;
    HR(factory->GetSystemFontCollection(&collection, TRUE));

    IDWriteFontFile *fontFile = NULL;
    // Get the system font collection.
    
    HR(factory->CreateFontFileReference(utf8ToUtf16(fontfile.c_str()), NULL, &fontFile));
    if (fontFile) {
        BOOL isSupported;
        DWRITE_FONT_FILE_TYPE fileType;
        DWRITE_FONT_FACE_TYPE fontFaceType;
        UINT32 numFaces;
        IDWriteFontFace* fontFace = NULL;
        fontFile->Analyze(&isSupported, &fileType, &fontFaceType, &numFaces);
        factory->CreateFontFace(fontFaceType, 1, &fontFile, 0, DWRITE_FONT_SIMULATIONS_NONE, &fontFace);
        IDWriteFont *font = NULL;
        collection->GetFontFromFontFace(fontFace, &font);
        fontMetaDataPtr* result = resultFromFont(font);
    }
 }
 result = RemoveFontResourceW(wideFontFilePath.c_str());

Answer 1

我找到了解决此问题的方法

HR(DWriteCreateFactory(
        DWRITE_FACTORY_TYPE_SHARED,
        __uuidof(IDWriteFactory3),
        reinterpret_cast<IUnknown **>(&factory)));

    HR(factory->CreateFontSetBuilder(&fontSetBuilder));
    HR(factory->CreateFontFileReference(utf8ToUtf16(fontFilePath.c_str()), NULL, &fontFile));

    if (fontFile) {
        
        fontFile->Analyze(&isSupported, &fileType, &fontFaceType, &numberOfFonts);
        // If there are more than 1 fonts are there, then we are taking only first index of the font
        // TODO: need to check for multiple fonts
        IDWriteFontFaceReference* fontFaceReference;
        factory->CreateFontFaceReference(fontFile, 0, DWRITE_FONT_SIMULATIONS_NONE, &fontFaceReference);
        fontSetBuilder->AddFontFaceReference(fontFaceReference);
        
        IDWriteFontSet* customFontSet;
        fontSetBuilder->CreateFontSet(&customFontSet);
        UINT32 fontCnt = customFontSet->GetFontCount();
        if (fontCnt > 1) {
            // TODO: need to check for multiple fonts
        }
        string postscriptName = getStringFromFontSet(customFontSet, DWRITE_FONT_PROPERTY_ID_POSTSCRIPT_NAME);
   }

像这样使用 IDWriteFontSet and DWRITE_FONT_PROPERTY_ID enum from dwrite_3.h 帮助我找到了解决方案。

如何从 windows OS 下载但尚未安装的字体文件中获取 IDWriteFont 对象

How to get the IDWriteFont object from the font file downloaded in windows OS and not installed yet

c++

directwrite