SkFontMgr.h revision 78358bf624c7e7c09ffccf638c50870808d884d6 
1/*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkFontMgr_DEFINED
9#define SkFontMgr_DEFINED
10
11#include "SkRefCnt.h"
12#include "SkFontStyle.h"
13
14class SkData;
15class SkStream;
16class SkString;
17class SkTypeface;
18
19class SK_API SkFontStyleSet : public SkRefCnt {
20public:
21    SK_DECLARE_INST_COUNT(SkFontStyleSet)
22
23    virtual int count() = 0;
24    virtual void getStyle(int index, SkFontStyle*, SkString* style) = 0;
25    virtual SkTypeface* createTypeface(int index) = 0;
26    virtual SkTypeface* matchStyle(const SkFontStyle& pattern) = 0;
27
28    static SkFontStyleSet* CreateEmpty();
29
30private:
31    typedef SkRefCnt INHERITED;
32};
33
34class SkTypeface;
35
36class SK_API SkFontMgr : public SkRefCnt {
37public:
38    SK_DECLARE_INST_COUNT(SkFontMgr)
39
40    int countFamilies() const;
41    void getFamilyName(int index, SkString* familyName) const;
42    SkFontStyleSet* createStyleSet(int index) const;
43
44    /**
45     *  The caller must call unref() on the returned object.
46     *  Never returns NULL; will return an empty set if the name is not found.
47     *
48     *  It is possible that this will return a style set not accessible from
49     *  createStyleSet(int) due to hidden or auto-activated fonts.
50     */
51    SkFontStyleSet* matchFamily(const char familyName[]) const;
52
53    /**
54     *  Find the closest matching typeface to the specified familyName and style
55     *  and return a ref to it. The caller must call unref() on the returned
56     *  object. Will never return NULL, as it will return the default font if
57     *  no matching font is found.
58     *
59     *  It is possible that this will return a style set not accessible from
60     *  createStyleSet(int) or matchFamily(const char[]) due to hidden or
61     *  auto-activated fonts.
62     */
63    SkTypeface* matchFamilyStyle(const char familyName[], const SkFontStyle&) const;
64
65    /**
66     *  Use the system fallback to find a typeface for the given character.
67     *  Note that bpc47 is a combination of ISO 639, 15924, and 3166-1 codes,
68     *  so it is fine to just pass a ISO 639 here.
69     *
70     *  Will return NULL if no family can be found for the character
71     *  in the system fallback.
72     */
73    SkTypeface* matchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
74                                          const char bpc47[], uint32_t character) const;
75
76    SkTypeface* matchFaceStyle(const SkTypeface*, const SkFontStyle&) const;
77
78    /**
79     *  Create a typeface for the specified data and TTC index (pass 0 for none)
80     *  or NULL if the data is not recognized. The caller must call unref() on
81     *  the returned object if it is not null.
82     */
83    SkTypeface* createFromData(SkData*, int ttcIndex = 0) const;
84
85    /**
86     *  Create a typeface for the specified stream and TTC index
87     *  (pass 0 for none) or NULL if the stream is not recognized. The caller
88     *  must call unref() on the returned object if it is not null.
89     */
90    SkTypeface* createFromStream(SkStream*, int ttcIndex = 0) const;
91
92    /**
93     *  Create a typeface for the specified fileName and TTC index
94     *  (pass 0 for none) or NULL if the file is not found, or its contents are
95     *  not recognized. The caller must call unref() on the returned object
96     *  if it is not null.
97     */
98    SkTypeface* createFromFile(const char path[], int ttcIndex = 0) const;
99
100    SkTypeface* legacyCreateTypeface(const char familyName[],
101                                     unsigned typefaceStyleBits) const;
102
103    /**
104     *  Return a ref to the default fontmgr. The caller must call unref() on
105     *  the returned object.
106     */
107    static SkFontMgr* RefDefault();
108
109protected:
110    virtual int onCountFamilies() const = 0;
111    virtual void onGetFamilyName(int index, SkString* familyName) const = 0;
112    virtual SkFontStyleSet* onCreateStyleSet(int index)const  = 0;
113
114    /** May return NULL if the name is not found. */
115    virtual SkFontStyleSet* onMatchFamily(const char familyName[]) const = 0;
116
117    virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
118                                           const SkFontStyle&) const = 0;
119    // TODO: pure virtual, implement on all impls.
120    virtual SkTypeface* onMatchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
121                                                    const char bpc47[], uint32_t character) const
122    { return NULL; }
123    virtual SkTypeface* onMatchFaceStyle(const SkTypeface*,
124                                         const SkFontStyle&) const = 0;
125
126    virtual SkTypeface* onCreateFromData(SkData*, int ttcIndex) const = 0;
127    virtual SkTypeface* onCreateFromStream(SkStream*, int ttcIndex) const = 0;
128    virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const = 0;
129
130    virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
131                                               unsigned styleBits) const = 0;
132private:
133    static SkFontMgr* Factory();    // implemented by porting layer
134    static SkFontMgr* CreateDefault();
135
136    typedef SkRefCnt INHERITED;
137};
138
139#endif
140