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 "SkFontStyle.h"
12#include "SkRefCnt.h"
13#include "SkScalar.h"
14#include "SkTypes.h"
15
16class SkData;
17class SkFontData;
18class SkStreamAsset;
19class SkString;
20class SkTypeface;
21
22class SK_API SkFontStyleSet : public SkRefCnt {
23public:
24    virtual int count() = 0;
25    virtual void getStyle(int index, SkFontStyle*, SkString* style) = 0;
26    virtual SkTypeface* createTypeface(int index) = 0;
27    virtual SkTypeface* matchStyle(const SkFontStyle& pattern) = 0;
28
29    static SkFontStyleSet* CreateEmpty();
30
31protected:
32    SkTypeface* matchStyleCSS3(const SkFontStyle& pattern);
33
34private:
35    typedef SkRefCnt INHERITED;
36};
37
38class SK_API SkFontMgr : public SkRefCnt {
39public:
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     *  Passing |nullptr| as the parameter will return the default system font.
49     *
50     *  It is possible that this will return a style set not accessible from
51     *  createStyleSet(int) due to hidden or auto-activated fonts.
52     */
53    SkFontStyleSet* matchFamily(const char familyName[]) const;
54
55    /**
56     *  Find the closest matching typeface to the specified familyName and style
57     *  and return a ref to it. The caller must call unref() on the returned
58     *  object. Will never return NULL, as it will return the default font if
59     *  no matching font is found.
60     *
61     *  Passing |nullptr| as the parameter for |familyName| will return the
62     *  default system font.
63     *
64     *  It is possible that this will return a style set not accessible from
65     *  createStyleSet(int) or matchFamily(const char[]) due to hidden or
66     *  auto-activated fonts.
67     */
68    SkTypeface* matchFamilyStyle(const char familyName[], const SkFontStyle&) const;
69
70    /**
71     *  Use the system fallback to find a typeface for the given character.
72     *  Note that bcp47 is a combination of ISO 639, 15924, and 3166-1 codes,
73     *  so it is fine to just pass a ISO 639 here.
74     *
75     *  Will return NULL if no family can be found for the character
76     *  in the system fallback.
77     *
78     *  Passing |nullptr| as the parameter for |familyName| will return the
79     *  default system font.
80     *
81     *  bcp47[0] is the least significant fallback, bcp47[bcp47Count-1] is the
82     *  most significant. If no specified bcp47 codes match, any font with the
83     *  requested character will be matched.
84     */
85    SkTypeface* matchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
86                                          const char* bcp47[], int bcp47Count,
87                                          SkUnichar character) const;
88
89    SkTypeface* matchFaceStyle(const SkTypeface*, const SkFontStyle&) const;
90
91    /**
92     *  Create a typeface for the specified data and TTC index (pass 0 for none)
93     *  or NULL if the data is not recognized. The caller must call unref() on
94     *  the returned object if it is not null.
95     */
96    SkTypeface* createFromData(SkData*, int ttcIndex = 0) const;
97
98    /**
99     *  Create a typeface for the specified stream and TTC index
100     *  (pass 0 for none) or NULL if the stream is not recognized. The caller
101     *  must call unref() on the returned object if it is not null.
102     */
103    SkTypeface* createFromStream(SkStreamAsset*, int ttcIndex = 0) const;
104
105    struct FontParameters {
106        struct Axis {
107            SkFourByteTag fTag;
108            SkScalar fStyleValue;
109        };
110
111        FontParameters() : fCollectionIndex(0), fAxisCount(0), fAxes(nullptr) {}
112
113        /** Specify the index of the desired font.
114         *
115         *  Font formats like ttc, dfont, cff, cid, pfr, t42, t1, and fon may actually be indexed
116         *  collections of fonts.
117         */
118        FontParameters& setCollectionIndex(int collectionIndex) {
119            fCollectionIndex = collectionIndex;
120            return *this;
121        }
122
123        /** Specify the GX variation axis values.
124         *
125         *  Any axes not specified will use the default value. Specified axes not present in the
126         *  font will be ignored.
127         *
128         *  @param axes not copied. This pointer must remain valid for life of FontParameters.
129         */
130        FontParameters& setAxes(const Axis* axes, int axisCount) {
131            fAxisCount = axisCount;
132            fAxes = axes;
133            return *this;
134        }
135
136        int getCollectionIndex() const {
137            return fCollectionIndex;
138        }
139        const Axis* getAxes(int* axisCount) const {
140            *axisCount = fAxisCount;
141            return fAxes;
142        }
143    private:
144        int fCollectionIndex;
145        int fAxisCount;
146        const Axis* fAxes;
147    };
148    /* Experimental, API subject to change. */
149    SkTypeface* createFromStream(SkStreamAsset*, const FontParameters&) const;
150
151    /**
152     *  Create a typeface from the specified font data.
153     *  Takes ownership of the font data, so the caller should not reference it again.
154     *  Will return NULL if the typeface could not be created.
155     *  The caller must call unref() on the returned object if it is not null.
156     */
157    SkTypeface* createFromFontData(SkFontData*) const;
158
159    /**
160     *  Create a typeface for the specified fileName and TTC index
161     *  (pass 0 for none) or NULL if the file is not found, or its contents are
162     *  not recognized. The caller must call unref() on the returned object
163     *  if it is not null.
164     */
165    SkTypeface* createFromFile(const char path[], int ttcIndex = 0) const;
166
167    SkTypeface* legacyCreateTypeface(const char familyName[],
168                                     unsigned typefaceStyleBits) const;
169
170    /**
171     *  Return a ref to the default fontmgr. The caller must call unref() on
172     *  the returned object.
173     */
174    static SkFontMgr* RefDefault();
175
176protected:
177    virtual int onCountFamilies() const = 0;
178    virtual void onGetFamilyName(int index, SkString* familyName) const = 0;
179    virtual SkFontStyleSet* onCreateStyleSet(int index)const  = 0;
180
181    /** May return NULL if the name is not found. */
182    virtual SkFontStyleSet* onMatchFamily(const char familyName[]) const = 0;
183
184    virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
185                                           const SkFontStyle&) const = 0;
186    virtual SkTypeface* onMatchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
187                                                    const char* bcp47[], int bcp47Count,
188                                                    SkUnichar character) const = 0;
189    virtual SkTypeface* onMatchFaceStyle(const SkTypeface*,
190                                         const SkFontStyle&) const = 0;
191
192    virtual SkTypeface* onCreateFromData(SkData*, int ttcIndex) const = 0;
193    virtual SkTypeface* onCreateFromStream(SkStreamAsset*, int ttcIndex) const = 0;
194    // TODO: make pure virtual.
195    virtual SkTypeface* onCreateFromStream(SkStreamAsset*, const FontParameters&) const;
196    virtual SkTypeface* onCreateFromFontData(SkFontData*) const;
197    virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const = 0;
198
199    virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
200                                               unsigned styleBits) const = 0;
201private:
202    static SkFontMgr* Factory();    // implemented by porting layer
203    friend SkFontMgr* sk_fontmgr_create_default();
204
205    typedef SkRefCnt INHERITED;
206};
207
208#endif
209