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* Copyright 2013 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkFontConfigInterface_DEFINED
#define SkFontConfigInterface_DEFINED
#include "SkFontStyle.h"
#include "SkRefCnt.h"
#include "SkTypeface.h"
class SkFontMgr;
* \class SkFontConfigInterface
* A simple interface for remotable font management.
* The global instance can be found with RefGlobal().
class SK_API SkFontConfigInterface : public SkRefCnt {
* Returns the global SkFontConfigInterface instance. If it is not
* nullptr, calls ref() on it. The caller must balance this with a call to
* unref(). The default SkFontConfigInterface is the result of calling
* GetSingletonDirectInterface.
static SkFontConfigInterface* RefGlobal();
* Replace the current global instance with the specified one, safely
* ref'ing the new instance, and unref'ing the previous. Returns its
* parameter (the new global instance).
static SkFontConfigInterface* SetGlobal(SkFontConfigInterface*);
* This should be treated as private to the impl of SkFontConfigInterface.
* Callers should not change or expect any particular values. It is meant
* to be a union of possible storage types to aid the impl.
struct FontIdentity {
FontIdentity() : fID(0), fTTCIndex(0) {}
bool operator==(const FontIdentity& other) const {
return fID == other.fID &&
fTTCIndex == other.fTTCIndex &&
fString == other.fString;
bool operator!=(const FontIdentity& other) const {
return !(*this == other);
uint32_t fID;
int32_t fTTCIndex;
SkString fString;
SkFontStyle fStyle;
// If buffer is NULL, just return the number of bytes that would have
// been written. Will pad contents to a multiple of 4.
size_t writeToMemory(void* buffer = nullptr) const;
// Recreate from a flattened buffer, returning the number of bytes read.
size_t readFromMemory(const void* buffer, size_t length);
* Given a familyName and style, find the best match.
* If a match is found, return true and set its outFontIdentifier.
* If outFamilyName is not null, assign the found familyName to it
* (which may differ from the requested familyName).
* If outStyle is not null, assign the found style to it
* (which may differ from the requested style).
* If a match is not found, return false, and ignore all out parameters.
virtual bool matchFamilyName(const char familyName[],
SkFontStyle requested,
FontIdentity* outFontIdentifier,
SkString* outFamilyName,
SkFontStyle* outStyle) = 0;
* Given a FontRef, open a stream to access its data, or return null
* if the FontRef's data is not available. The caller is responsible for
* deleting the stream when it is done accessing the data.
virtual SkStreamAsset* openStream(const FontIdentity&) = 0;
* Return an SkTypeface for the given FontIdentity.
* The default implementation simply returns a new typeface built using data obtained from
* openStream(), but derived classes may implement more complex caching schemes.
virtual sk_sp<SkTypeface> makeTypeface(const FontIdentity& identity) {
return SkTypeface::MakeFromStream(this->openStream(identity), identity.fTTCIndex);
* Return a singleton instance of a direct subclass that calls into
* libfontconfig. This does not affect the refcnt of the returned instance.
static SkFontConfigInterface* GetSingletonDirectInterface();
typedef SkRefCnt INHERITED;