C++ IDWriteFont::GetFontFamily方法代码示例

HRESULT DWriteCreateResources(HDC hdc, wchar_t *text, HFONT hfont)
{
    HRESULT hr = S_OK;

    // If the DirectWrite factory doesn't exist, create the resources,
    // only create these resources once.
    if (!g_pDWriteFactory)
    {
        HWND hwnd;
        RECT r;

        // DirectWrite variables.
        IDWriteFontFamily* pFontFamily = NULL;
        IDWriteFont* pFont = NULL;
        IDWriteLocalizedStrings* pFamilyNames = NULL;
        
        // Logical (GDI) font.
        LOGFONT lf = {};

        UINT32 length = 0;
        UINT32 index = 0;
        float fontSize = 0;

        // length of the string
        UINT32 textLength = 0;

        wchar_t *name = NULL;

        // Get a handle to the DC and the window rect.
        hwnd = WindowFromDC(hdc);
        GetClientRect(hwnd, &r);

        // Calculate the string length.
        textLength = UINT32(wcslen(text));

        // Create the DirectWrite factory.
        hr = DWriteCreateFactory(
            DWRITE_FACTORY_TYPE_SHARED,
            __uuidof(IDWriteFactory),
            reinterpret_cast<IUnknown**>(&g_pDWriteFactory)
            );

        // Create a GDI interop interface.
        if (SUCCEEDED(hr))
        {
            hr = g_pDWriteFactory->GetGdiInterop(&g_pGdiInterop);
        }
        
        if (SUCCEEDED(hr))
        {
            // Get a logical font from the font handle.
            GetObject(hfont, sizeof(LOGFONT), &lf);
        }

        // Convert to a DirectWrite font.
        if (SUCCEEDED(hr))
        {
            hr = g_pGdiInterop->CreateFontFromLOGFONT(&lf, &pFont);
        }
        
        // Get the font family.
        if (SUCCEEDED(hr))
        {
            hr = pFont->GetFontFamily(&pFontFamily);
        }

        // Get a list of localized family names.
        if (SUCCEEDED(hr))
        {
            hr = pFontFamily->GetFamilyNames(&pFamilyNames);
        }

        // Select the first locale.  This is OK, because we are not displaying the family name.
        index = 0;
        
        // Get the length of the family name.
        if (SUCCEEDED(hr))
        {
            hr = pFamilyNames->GetStringLength(index, &length);
        }

        if (SUCCEEDED(hr))
        {
            // Allocate a new string.
            name = new (std::nothrow) wchar_t[length+1];
		    if (name == NULL)
            {
			    hr = E_OUTOFMEMORY;
            }
        }

        // Get the actual family name.
        if (SUCCEEDED(hr))
        {
            hr = pFamilyNames->GetString(index, name, length+1);
        }

        if (SUCCEEDED(hr))
        {
            // Calculate the font size.
//.........这里部分代码省略.........

    HRESULT
DWriteContext::SetLOGFONT(const LOGFONTW &logFont, float fontSize)
{
    // Most of this function is copy from: http://msdn.microsoft.com/en-us/library/windows/desktop/dd941783(v=vs.85).aspx
    HRESULT hr = S_OK;

    IDWriteFont *font = NULL;
    IDWriteFontFamily *fontFamily = NULL;
    IDWriteLocalizedStrings *localizedFamilyNames = NULL;

    if (SUCCEEDED(hr))
    {
	hr = mGdiInterop->CreateFontFromLOGFONT(&logFont, &font);
    }

    // Get the font family to which this font belongs.
    if (SUCCEEDED(hr))
    {
	hr = font->GetFontFamily(&fontFamily);
    }

    // Get the family names. This returns an object that encapsulates one or
    // more names with the same meaning but in different languages.
    if (SUCCEEDED(hr))
    {
	hr = fontFamily->GetFamilyNames(&localizedFamilyNames);
    }

    // Get the family name at index zero. If we were going to display the name
    // we'd want to try to find one that matched the use locale, but for
    // purposes of creating a text format object any language will do.

    wchar_t familyName[100];
    if (SUCCEEDED(hr))
    {
	hr = localizedFamilyNames->GetString(0, familyName,
		ARRAYSIZE(familyName));
    }

    if (SUCCEEDED(hr))
    {
	// If no font size was passed in use the lfHeight of the LOGFONT.
	if (fontSize == 0)
	{
	    // Convert from pixels to DIPs.
	    fontSize = PixelsToDipsY(logFont.lfHeight);
	    if (fontSize < 0)
	    {
		// Negative lfHeight represents the size of the em unit.
		fontSize = -fontSize;
	    }
	    else
	    {
		// Positive lfHeight represents the cell height (ascent +
		// descent).
		DWRITE_FONT_METRICS fontMetrics;
		font->GetMetrics(&fontMetrics);

		// Convert the cell height (ascent + descent) from design units
		// to ems.
		float cellHeight = static_cast<float>(
			fontMetrics.ascent + fontMetrics.descent)
					       / fontMetrics.designUnitsPerEm;

		// Divide the font size by the cell height to get the font em
		// size.
		fontSize /= cellHeight;
	    }
	}
    }

    // The text format includes a locale name. Ideally, this would be the
    // language of the text, which may or may not be the same as the primary
    // language of the user. However, for our purposes the user locale will do.
    wchar_t localeName[LOCALE_NAME_MAX_LENGTH];
    if (SUCCEEDED(hr))
    {
	if (GetUserDefaultLocaleName(localeName, LOCALE_NAME_MAX_LENGTH) == 0)
	    hr = HRESULT_FROM_WIN32(GetLastError());
    }

    if (SUCCEEDED(hr))
    {
	// Create the text format object.
	hr = mDWriteFactory->CreateTextFormat(
		familyName,
		NULL, // no custom font collection
		font->GetWeight(),
		font->GetStyle(),
		font->GetStretch(),
		fontSize,
		localeName,
		&mTextFormat);
    }

    if (SUCCEEDED(hr))
    {
	mFontWeight = static_cast<DWRITE_FONT_WEIGHT>(logFont.lfWeight);
	mFontStyle = logFont.lfItalic ? DWRITE_FONT_STYLE_ITALIC
	    : DWRITE_FONT_STYLE_NORMAL;
//.........这里部分代码省略.........