skia2/include/ports/SkFontMgr.h
bungeman 7575bb1c38 SkFontMgr::matchFamily should not crash on nullptr.
While all systems can resolve a font from just a style request
(without a name) almost no systems specify a default font family.

BUG=skia:6574

Change-Id: If7c81808b62cd5d8212bce2eb4d9c476c45af80a
Reviewed-on: https://skia-review.googlesource.com/14902
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2017-05-01 18:13:02 +00:00

166 lines
6.3 KiB
C++

/*
* 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 SkFontMgr_DEFINED
#define SkFontMgr_DEFINED
#include "SkFontArguments.h"
#include "SkFontStyle.h"
#include "SkRefCnt.h"
#include "SkTypes.h"
class SkData;
class SkFontData;
class SkStreamAsset;
class SkString;
class SkTypeface;
class SK_API SkFontStyleSet : public SkRefCnt {
public:
virtual int count() = 0;
virtual void getStyle(int index, SkFontStyle*, SkString* style) = 0;
virtual SkTypeface* createTypeface(int index) = 0;
virtual SkTypeface* matchStyle(const SkFontStyle& pattern) = 0;
static SkFontStyleSet* CreateEmpty();
protected:
SkTypeface* matchStyleCSS3(const SkFontStyle& pattern);
private:
typedef SkRefCnt INHERITED;
};
class SK_API SkFontMgr : public SkRefCnt {
public:
int countFamilies() const;
void getFamilyName(int index, SkString* familyName) const;
SkFontStyleSet* createStyleSet(int index) const;
/**
* The caller must call unref() on the returned object.
* Never returns NULL; will return an empty set if the name is not found.
*
* Passing nullptr as the parameter will return the default system family.
* Note that most systems don't have a default system family, so passing nullptr will often
* result in the empty set.
*
* It is possible that this will return a style set not accessible from
* createStyleSet(int) due to hidden or auto-activated fonts.
*/
SkFontStyleSet* matchFamily(const char familyName[]) const;
/**
* Find the closest matching typeface to the specified familyName and style
* and return a ref to it. The caller must call unref() on the returned
* object. Will never return NULL, as it will return the default font if
* no matching font is found.
*
* Passing |nullptr| as the parameter for |familyName| will return the
* default system font.
*
* It is possible that this will return a style set not accessible from
* createStyleSet(int) or matchFamily(const char[]) due to hidden or
* auto-activated fonts.
*/
SkTypeface* matchFamilyStyle(const char familyName[], const SkFontStyle&) const;
/**
* Use the system fallback to find a typeface for the given character.
* Note that bcp47 is a combination of ISO 639, 15924, and 3166-1 codes,
* so it is fine to just pass a ISO 639 here.
*
* Will return NULL if no family can be found for the character
* in the system fallback.
*
* Passing |nullptr| as the parameter for |familyName| will return the
* default system font.
*
* bcp47[0] is the least significant fallback, bcp47[bcp47Count-1] is the
* most significant. If no specified bcp47 codes match, any font with the
* requested character will be matched.
*/
SkTypeface* matchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
const char* bcp47[], int bcp47Count,
SkUnichar character) const;
SkTypeface* matchFaceStyle(const SkTypeface*, const SkFontStyle&) const;
/**
* Create a typeface for the specified data and TTC index (pass 0 for none)
* or NULL if the data is not recognized. The caller must call unref() on
* the returned object if it is not null.
*/
SkTypeface* createFromData(SkData*, int ttcIndex = 0) const;
/**
* Create a typeface for the specified stream and TTC index
* (pass 0 for none) or NULL if the stream is not recognized. The caller
* must call unref() on the returned object if it is not null.
*/
SkTypeface* createFromStream(SkStreamAsset*, int ttcIndex = 0) const;
// deprecated, use SkFontArguments instead.
using FontParameters = SkFontArguments;
/* Experimental, API subject to change. */
SkTypeface* createFromStream(SkStreamAsset*, const SkFontArguments&) const;
/**
* Create a typeface from the specified font data.
* Will return NULL if the typeface could not be created.
* The caller must call unref() on the returned object if it is not null.
*/
SkTypeface* createFromFontData(std::unique_ptr<SkFontData>) const;
/**
* Create a typeface for the specified fileName and TTC index
* (pass 0 for none) or NULL if the file is not found, or its contents are
* not recognized. The caller must call unref() on the returned object
* if it is not null.
*/
SkTypeface* createFromFile(const char path[], int ttcIndex = 0) const;
SkTypeface* legacyCreateTypeface(const char familyName[], SkFontStyle style) const;
/** Return the default fontmgr. */
static sk_sp<SkFontMgr> RefDefault();
protected:
virtual int onCountFamilies() const = 0;
virtual void onGetFamilyName(int index, SkString* familyName) const = 0;
virtual SkFontStyleSet* onCreateStyleSet(int index)const = 0;
/** May return NULL if the name is not found. */
virtual SkFontStyleSet* onMatchFamily(const char familyName[]) const = 0;
virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
const SkFontStyle&) const = 0;
virtual SkTypeface* onMatchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
const char* bcp47[], int bcp47Count,
SkUnichar character) const = 0;
virtual SkTypeface* onMatchFaceStyle(const SkTypeface*,
const SkFontStyle&) const = 0;
virtual SkTypeface* onCreateFromData(SkData*, int ttcIndex) const = 0;
virtual SkTypeface* onCreateFromStream(SkStreamAsset*, int ttcIndex) const = 0;
// TODO: make pure virtual.
virtual SkTypeface* onCreateFromStream(SkStreamAsset*, const SkFontArguments&) const;
virtual SkTypeface* onCreateFromFontData(std::unique_ptr<SkFontData>) const;
virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const = 0;
virtual SkTypeface* onLegacyCreateTypeface(const char familyName[], SkFontStyle) const = 0;
private:
/** Implemented by porting layer to return the default factory. */
static sk_sp<SkFontMgr> Factory();
typedef SkRefCnt INHERITED;
};
#endif