internal void Canonicalize()
{
if (_canonicalReferences != null)
{
return;
}
int count = this.Count;
if (count == 0)
{
return;
}
// First look up the entire friendly name in the cache; this may enable us to
// save working set by sharing the same array of may equal FontFamilyIdentifier.
BasedFriendlyName hashKey = new BasedFriendlyName(_baseUri, _friendlyName);
CanonicalFontFamilyReference[] canonicalReferences = TypefaceMetricsCache.ReadonlyLookup(hashKey) as CanonicalFontFamilyReference[];
if (canonicalReferences == null)
{
// We need to construct a new array.
canonicalReferences = new CanonicalFontFamilyReference[count];
// Add the first canonical family reference.
int i, length;
int j = FindToken(_friendlyName, 0, out i, out length);
canonicalReferences[0] = GetCanonicalReference(i, length);
// Add subsequent family references.
for (int k = 1; k < count; ++k)
{
j = FindToken(_friendlyName, j, out i, out length);
canonicalReferences[k] = GetCanonicalReference(i, length);
}
// Add the array to the cache.
TypefaceMetricsCache.Add(hashKey, canonicalReferences);
}
// for thread safety, we assign to the field only after the array is fully initialized
_canonicalReferences = canonicalReferences;
}
private CanonicalFontFamilyReference GetCanonicalReference(int startIndex, int length)
{
string normalizedString = Util.GetNormalizedFontFamilyReference(_friendlyName, startIndex, length);
// For caching normalized names, we use a different type of key which does not compare equal
// to the keys we used for caching friendly names.
BasedNormalizedName hashKey = new BasedNormalizedName(_baseUri, normalizedString);
// Look up the normalized string and base URI in the cache?
CanonicalFontFamilyReference canonicalReference = TypefaceMetricsCache.ReadonlyLookup(hashKey) as CanonicalFontFamilyReference;
// Do we already have a cached font family reference?
if (canonicalReference == null)
{
// Not in cache. Construct a new font family reference.
canonicalReference = CanonicalFontFamilyReference.Create(_baseUri, normalizedString);
// Add it to the cache.
TypefaceMetricsCache.Add(hashKey, canonicalReference);
}
return(canonicalReference);
}
private CachedTypeface ConstructCachedTypeface()
{
FontStyle canonicalStyle = _style;
FontWeight canonicalWeight = _weight;
FontStretch canonicalStretch = _stretch;
//
// We always call FontFamily.FindFirstFontFamilyAndFace() method to resolve the
// canonical styles since the implied styles in FontFamily name will override
// the given styles in the Typeface. But we don't always use the IFontFamily
// instance returned from this method because an equal instance might already be
// cached.
//
FontFamily sourceFontFamily = FontFamily;
IFontFamily firstFontFamily = sourceFontFamily.FindFirstFontFamilyAndFace(
ref canonicalStyle,
ref canonicalWeight,
ref canonicalStretch
);
if (firstFontFamily == null)
{
if (FallbackFontFamily != null)
{
sourceFontFamily = FallbackFontFamily;
firstFontFamily = sourceFontFamily.FindFirstFontFamilyAndFace(
ref canonicalStyle,
ref canonicalWeight,
ref canonicalStretch
);
}
if (firstFontFamily == null)
{
sourceFontFamily = null;
firstFontFamily = FontFamily.LookupFontFamily(FontFamily.NullFontFamilyCanonicalName);
}
}
// If it's a named font, map all occurrences of the same name to one cached IFontFamily.
if (sourceFontFamily != null && sourceFontFamily.Source != null)
{
// We lookup in the cache to see if there is cached IFontFamily instance of the source FontFamily. Otherwise,
// this IFontFamily value is added to the TypefaceMetrics cache.
IFontFamily cachedValue = TypefaceMetricsCache.ReadonlyLookup(sourceFontFamily.FamilyIdentifier) as IFontFamily;
if (cachedValue != null)
{
firstFontFamily = cachedValue;
}
else
{
TypefaceMetricsCache.Add(sourceFontFamily.FamilyIdentifier, firstFontFamily);
}
}
ITypefaceMetrics typefaceMetrics = firstFontFamily.GetTypefaceMetrics(canonicalStyle, canonicalWeight, canonicalStretch);
return(new CachedTypeface(
canonicalStyle,
canonicalWeight,
canonicalStretch,
firstFontFamily,
typefaceMetrics,
sourceFontFamily == null
));
}
