// This method takes an attributed string and outputs a GlyphLayout data
// structure that contains the glyph number and location of each inidividual glyph
void getGlyphLayout (const AttributedString& text, GlyphLayout& glyphLayout)
{
// For now we are creating the DirectWrite Factory, System Font Collection,
// D2D Factory and GDI Render target every time we layout text.
// This is inefficient and we may be loading and unloading libraries each layout.
// These four things should be created once at application startup and be destroyed
// when the application exits. I'm not sure where the best place to do this so
// for now I will just use the inefficient method.
IDWriteFactory* dwFactory = nullptr;
HRESULT hr = DWriteCreateFactory (DWRITE_FACTORY_TYPE_SHARED, __uuidof(IDWriteFactory),
reinterpret_cast<IUnknown**>(&dwFactory));
IDWriteFontCollection* dwFontCollection = nullptr;
hr = dwFactory->GetSystemFontCollection (&dwFontCollection);
// To add color to text, we need to create a D2D render target
// Since we are not actually rendering to a D2D context we create a temporary GDI render target
ID2D1Factory *d2dFactory = nullptr;
hr = D2D1CreateFactory (D2D1_FACTORY_TYPE_SINGLE_THREADED, &d2dFactory);
D2D1_RENDER_TARGET_PROPERTIES d2dRTProp = D2D1::RenderTargetProperties(
D2D1_RENDER_TARGET_TYPE_SOFTWARE,
D2D1::PixelFormat(
DXGI_FORMAT_B8G8R8A8_UNORM,
D2D1_ALPHA_MODE_IGNORE),
0,
0,
D2D1_RENDER_TARGET_USAGE_GDI_COMPATIBLE,
D2D1_FEATURE_LEVEL_DEFAULT
);
ID2D1DCRenderTarget* d2dDCRT = nullptr;
hr = d2dFactory->CreateDCRenderTarget (&d2dRTProp, &d2dDCRT);
// Initially we set the paragraph up with a default font and then apply the attributed string ranges later
Font defaultFont;
const float defaultFontHeightToEmSizeFactor = getFontHeightToEmSizeFactor (defaultFont, *dwFontCollection);
// We should probably be detecting the locale instead of hard coding it to en-us
String localeName("en-us");
// We multiply the font height by the size factor so we layout text at the correct size
IDWriteTextFormat* dwTextFormat = nullptr;
hr = dwFactory->CreateTextFormat (
defaultFont.getTypefaceName().toWideCharPointer(),
dwFontCollection,
DWRITE_FONT_WEIGHT_REGULAR,
DWRITE_FONT_STYLE_NORMAL,
DWRITE_FONT_STRETCH_NORMAL,
defaultFont.getHeight() * defaultFontHeightToEmSizeFactor,
localeName.toWideCharPointer(),
&dwTextFormat
);
// Paragraph Attributes
// Set Paragraph Alignment
if (text.getTextAlignment() == AttributedString::left)
dwTextFormat->SetTextAlignment (DWRITE_TEXT_ALIGNMENT_LEADING);
if (text.getTextAlignment() == AttributedString::right)
dwTextFormat->SetTextAlignment (DWRITE_TEXT_ALIGNMENT_TRAILING);
if (text.getTextAlignment() == AttributedString::center)
dwTextFormat->SetTextAlignment (DWRITE_TEXT_ALIGNMENT_CENTER);
// DirectWrite cannot justify text, default to left alignment
if (text.getTextAlignment() == AttributedString::justified)
dwTextFormat->SetTextAlignment (DWRITE_TEXT_ALIGNMENT_LEADING);
// Set Word Wrap
if (text.getWordWrap() == AttributedString::none)
dwTextFormat->SetWordWrapping (DWRITE_WORD_WRAPPING_NO_WRAP);
if (text.getWordWrap() == AttributedString::byWord)
dwTextFormat->SetWordWrapping (DWRITE_WORD_WRAPPING_WRAP);
// DirectWrite does not support wrapping by character, default to wrapping by word
if (text.getWordWrap() == AttributedString::byChar)
dwTextFormat->SetWordWrapping (DWRITE_WORD_WRAPPING_WRAP);
// DirectWrite does not automatically set reading direction
// This must be set correctly and manually when using RTL Scripts (Hebrew, Arabic)
if (text.getReadingDirection() == AttributedString::rightToLeft)
dwTextFormat->SetReadingDirection (DWRITE_READING_DIRECTION_RIGHT_TO_LEFT);
IDWriteTextLayout* dwTextLayout = nullptr;
hr = dwFactory->CreateTextLayout (
text.getText().toWideCharPointer(),
text.getText().length(),
dwTextFormat,
glyphLayout.getWidth(),
glyphLayout.getHeight(),
&dwTextLayout
);
// Character Attributes
int numCharacterAttributes = text.getCharAttributesSize();
for (int i = 0; i < numCharacterAttributes; ++i)
{
Attr* attr = text.getCharAttribute (i);
// Character Range Error Checking
if (attr->range.getStart() > text.getText().length()) continue;
if (attr->range.getEnd() > text.getText().length()) attr->range.setEnd (text.getText().length());
if (attr->attribute == Attr::font)
{
AttrFont* attrFont = static_cast<AttrFont*>(attr);
DWRITE_TEXT_RANGE dwRange;
dwRange.startPosition = attrFont->range.getStart();
dwRange.length = attrFont->range.getLength();
dwTextLayout->SetFontFamilyName (attrFont->font.getTypefaceName().toWideCharPointer(), dwRange);
// We multiply the font height by the size factor so we layout text at the correct size
const float fontHeightToEmSizeFactor = getFontHeightToEmSizeFactor (attrFont->font, *dwFontCollection);
dwTextLayout->SetFontSize (attrFont->font.getHeight() * fontHeightToEmSizeFactor, dwRange);
}
if (attr->attribute == Attr::foregroundColour)
{
AttrColour* attrColour = static_cast<AttrColour*>(attr);
DWRITE_TEXT_RANGE dwRange;
dwRange.startPosition = attrColour->range.getStart();
dwRange.length = attrColour->range.getLength();
ID2D1SolidColorBrush* d2dBrush = nullptr;
d2dDCRT->CreateSolidColorBrush (D2D1::ColorF (D2D1::ColorF(attrColour->colour.getFloatRed(),
attrColour->colour.getFloatGreen(), attrColour->colour.getFloatBlue(),
attrColour->colour.getFloatAlpha())), &d2dBrush);
// We need to call SetDrawingEffect with a legimate brush to get DirectWrite to break text based on colours
dwTextLayout->SetDrawingEffect (d2dBrush, dwRange);
safeRelease (&d2dBrush);
}
}
UINT32 actualLineCount = 0;
hr = dwTextLayout->GetLineMetrics (nullptr, 0, &actualLineCount);
// Preallocate GlyphLayout Line Array
glyphLayout.setNumLines (actualLineCount);
HeapBlock <DWRITE_LINE_METRICS> dwLineMetrics (actualLineCount);
hr = dwTextLayout->GetLineMetrics (dwLineMetrics, actualLineCount, &actualLineCount);
int location = 0;
// Create GlyphLine structures for each line in the layout
for (UINT32 i = 0; i < actualLineCount; ++i)
{
// Get string range
Range<int> lineStringRange (location, (int) location + dwLineMetrics[i].length);
location = dwLineMetrics[i].length;
GlyphLine* glyphLine = new GlyphLine();
glyphLine->setStringRange (lineStringRange);
glyphLayout.addGlyphLine (glyphLine);
}
// To copy glyph data from DirectWrite into our own data structures we must create our
// own CustomTextRenderer. Instead of passing the draw method an actual graphics context,
// we pass it the GlyphLayout object that needs to be filled with glyphs.
CustomDirectWriteTextRenderer* textRenderer = nullptr;
textRenderer = new CustomDirectWriteTextRenderer();
hr = dwTextLayout->Draw (
&glyphLayout,
textRenderer,
glyphLayout.getX(),
glyphLayout.getY()
);
safeRelease (&textRenderer);
safeRelease (&dwTextLayout);
safeRelease (&dwTextFormat);
safeRelease (&d2dDCRT);
safeRelease (&d2dFactory);
safeRelease (&dwFontCollection);
safeRelease (&dwFactory);
}
virtual HRESULT STDMETHODCALLTYPE GetSystemFontCollection(
IDWriteFontCollection** fontCollection,
BOOL checkForUpdates = FALSE
)
{
return orig_this->GetSystemFontCollection(fontCollection, checkForUpdates);
}
void wmain()
{
IDWriteFactory* pDWriteFactory = NULL;
HRESULT hr = DWriteCreateFactory(
DWRITE_FACTORY_TYPE_SHARED,
__uuidof(IDWriteFactory),
reinterpret_cast<IUnknown**>(&pDWriteFactory)
);
IDWriteFontCollection* pFontCollection = NULL;
// Get the system font collection.
if (SUCCEEDED(hr))
{
hr = pDWriteFactory->GetSystemFontCollection(&pFontCollection);
}
UINT32 familyCount = 0;
// Get the number of font families in the collection.
if (SUCCEEDED(hr))
{
familyCount = pFontCollection->GetFontFamilyCount();
}
for (UINT32 i = 0; i < familyCount; ++i)
{
IDWriteFontFamily* pFontFamily = NULL;
// Get the font family.
if (SUCCEEDED(hr))
{
hr = pFontCollection->GetFontFamily(i, &pFontFamily);
}
IDWriteLocalizedStrings* pFamilyNames = NULL;
// Get a list of localized strings for the family name.
if (SUCCEEDED(hr))
{
hr = pFontFamily->GetFamilyNames(&pFamilyNames);
}
UINT32 index = 0;
BOOL exists = false;
wchar_t localeName[LOCALE_NAME_MAX_LENGTH];
if (SUCCEEDED(hr))
{
// Get the default locale for this user.
int defaultLocaleSuccess = GetUserDefaultLocaleName(localeName, LOCALE_NAME_MAX_LENGTH);
// If the default locale is returned, find that locale name, otherwise use "en-us".
if (defaultLocaleSuccess)
{
hr = pFamilyNames->FindLocaleName(localeName, &index, &exists);
}
else
{
hr = pFamilyNames->FindLocaleName(L"en-us", &index, &exists);
}
}
// If the specified locale doesn't exist, select the first on the list.
if (!exists)
index = 0;
UINT32 length = 0;
// Get the string length.
if (SUCCEEDED(hr))
{
hr = pFamilyNames->GetStringLength(index, &length);
}
// Allocate a string big enough to hold the name.
wchar_t* name = new (std::nothrow) wchar_t[length+1];
if (name == NULL)
{
hr = E_OUTOFMEMORY;
}
// Get the family name.
if (SUCCEEDED(hr))
{
hr = pFamilyNames->GetString(index, name, length+1);
}
if (SUCCEEDED(hr))
{
// Print out the family name.
wprintf(L"%s\n", name);
}
SafeRelease(&pFontFamily);
SafeRelease(&pFamilyNames);
delete [] name;
}
SafeRelease(&pFontCollection);
SafeRelease(&pDWriteFactory);
}