FontFamily.h revision 198b46f1fea3f47ef8eb6317799c0d77aaec52f6 
1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef MINIKIN_FONT_FAMILY_H
18#define MINIKIN_FONT_FAMILY_H
19
20#include <vector>
21#include <string>
22#include <hb.h>
23
24#include <utils/TypeHelpers.h>
25
26#include <minikin/MinikinRefCounted.h>
27#include <minikin/SparseBitSet.h>
28
29namespace android {
30
31class MinikinFont;
32
33// FontStyle represents all style information needed to select an actual font
34// from a collection. The implementation is packed into two 32-bit words
35// so it can be efficiently copied, embedded in other objects, etc.
36class FontStyle {
37public:
38    FontStyle() : FontStyle(0 /* variant */, 4 /* weight */, false /* italic */) {}
39    FontStyle(int weight, bool italic) : FontStyle(0 /* variant */, weight, italic) {}
40    FontStyle(uint32_t langListId)
41            : FontStyle(langListId, 0 /* variant */, 4 /* weight */, false /* italic */) {}
42
43    FontStyle(int variant, int weight, bool italic);
44    FontStyle(uint32_t langListId, int variant, int weight, bool italic);
45
46    int getWeight() const { return bits & kWeightMask; }
47    bool getItalic() const { return (bits & kItalicMask) != 0; }
48    int getVariant() const { return (bits >> kVariantShift) & kVariantMask; }
49    uint32_t getLanguageListId() const { return mLanguageListId; }
50
51    bool operator==(const FontStyle other) const {
52          return bits == other.bits && mLanguageListId == other.mLanguageListId;
53    }
54
55    hash_t hash() const;
56
57    // Looks up a language list from an internal cache and returns its ID.
58    // If the passed language list is not in the cache, registers it and returns newly assigned ID.
59    static uint32_t registerLanguageList(const std::string& languages);
60private:
61    static const uint32_t kWeightMask = (1 << 4) - 1;
62    static const uint32_t kItalicMask = 1 << 4;
63    static const int kVariantShift = 5;
64    static const uint32_t kVariantMask = (1 << 2) - 1;
65
66    static uint32_t pack(int variant, int weight, bool italic);
67
68    uint32_t bits;
69    uint32_t mLanguageListId;
70};
71
72enum FontVariant {
73    VARIANT_DEFAULT = 0,
74    VARIANT_COMPACT = 1,
75    VARIANT_ELEGANT = 2,
76};
77
78inline hash_t hash_type(const FontStyle &style) {
79    return style.hash();
80}
81
82// attributes representing transforms (fake bold, fake italic) to match styles
83class FontFakery {
84public:
85    FontFakery() : mFakeBold(false), mFakeItalic(false) { }
86    FontFakery(bool fakeBold, bool fakeItalic) : mFakeBold(fakeBold), mFakeItalic(fakeItalic) { }
87    // TODO: want to support graded fake bolding
88    bool isFakeBold() { return mFakeBold; }
89    bool isFakeItalic() { return mFakeItalic; }
90private:
91    bool mFakeBold;
92    bool mFakeItalic;
93};
94
95struct FakedFont {
96    // ownership is the enclosing FontCollection
97    MinikinFont* font;
98    FontFakery fakery;
99};
100
101class FontFamily : public MinikinRefCounted {
102public:
103    FontFamily() : mHbFont(nullptr) { }
104
105    FontFamily(int variant);
106
107    FontFamily(uint32_t langId, int variant) : mLangId(langId), mVariant(variant), mHbFont(nullptr) {
108    }
109
110    ~FontFamily();
111
112    // Add font to family, extracting style information from the font
113    bool addFont(MinikinFont* typeface);
114
115    void addFont(MinikinFont* typeface, FontStyle style);
116    FakedFont getClosestMatch(FontStyle style) const;
117
118    uint32_t langId() const { return mLangId; }
119    int variant() const { return mVariant; }
120
121    // API's for enumerating the fonts in a family. These don't guarantee any particular order
122    size_t getNumFonts() const;
123    MinikinFont* getFont(size_t index) const;
124    FontStyle getStyle(size_t index) const;
125
126    // Get Unicode coverage. Lifetime of returned bitset is same as receiver. May return nullptr on
127    // error.
128    const SparseBitSet* getCoverage();
129
130    // Returns true if the font has a glyph for the code point and variation selector pair.
131    // Caller should acquire a lock before calling the method.
132    bool hasVariationSelector(uint32_t codepoint, uint32_t variationSelector);
133
134    // Purges cached mHbFont.
135    // hb_font_t keeps a reference to hb_face_t which is managed by HbFaceCache. Thus,
136    // it is good to purge hb_font_t once it is no longer necessary.
137    // Caller should acquire a lock before calling the method.
138    void purgeHbFontCache();
139private:
140    void addFontLocked(MinikinFont* typeface, FontStyle style);
141
142    class Font {
143    public:
144        Font(MinikinFont* typeface, FontStyle style) :
145            typeface(typeface), style(style) { }
146        MinikinFont* typeface;
147        FontStyle style;
148    };
149    uint32_t mLangId;
150    int mVariant;
151    std::vector<Font> mFonts;
152
153    SparseBitSet mCoverage;
154    bool mCoverageValid;
155
156    hb_font_t* mHbFont;
157};
158
159}  // namespace android
160
161#endif  // MINIKIN_FONT_FAMILY_H
162