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_LAYOUT_H
18#define MINIKIN_LAYOUT_H
19
20#include <hb.h>
21
22#include <vector>
23
24#include <minikin/FontCollection.h>
25#include <minikin/MinikinFontFreeType.h>
26
27namespace minikin {
28
29// The Bitmap class is for debugging. We'll probably move it out
30// of here into a separate lightweight software rendering module
31// (optional, as we'd hope most clients would do their own)
32class Bitmap {
33public:
34    Bitmap(int width, int height);
35    ~Bitmap();
36    void writePnm(std::ofstream& o) const;
37    void drawGlyph(const android::GlyphBitmap& bitmap, int x, int y);
38private:
39    int width;
40    int height;
41    uint8_t* buf;
42};
43
44} // namespace minikin
45
46namespace android {
47
48struct LayoutGlyph {
49    // index into mFaces and mHbFonts vectors. We could imagine
50    // moving this into a run length representation, because it's
51    // more efficient for long strings, and we'll probably need
52    // something like that for paint attributes (color, underline,
53    // fake b/i, etc), as having those per-glyph is bloated.
54    int font_ix;
55
56    unsigned int glyph_id;
57    float x;
58    float y;
59};
60
61// Internal state used during layout operation
62class LayoutContext;
63
64enum {
65    kBidi_LTR = 0,
66    kBidi_RTL = 1,
67    kBidi_Default_LTR = 2,
68    kBidi_Default_RTL = 3,
69    kBidi_Force_LTR = 4,
70    kBidi_Force_RTL = 5,
71
72    kBidi_Mask = 0x7
73};
74
75// Lifecycle and threading assumptions for Layout:
76// The object is assumed to be owned by a single thread; multiple threads
77// may not mutate it at the same time.
78// The lifetime of the FontCollection set through setFontCollection must
79// extend through the lifetime of the Layout object.
80class Layout {
81public:
82
83    Layout() : mGlyphs(), mAdvances(), mCollection(0), mFaces(), mAdvance(0), mBounds() {
84        mBounds.setEmpty();
85    }
86
87    // Clears layout, ready to be used again
88    void reset();
89
90    void dump() const;
91    void setFontCollection(const FontCollection* collection);
92
93    void doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
94        int bidiFlags, const FontStyle &style, const MinikinPaint &paint);
95
96    void draw(minikin::Bitmap*, int x0, int y0, float size) const;
97
98    // Deprecated. Nont needed. Remove when callers are removed.
99    static void init();
100
101    // public accessors
102    size_t nGlyphs() const;
103    // Does not bump reference; ownership is still layout
104    MinikinFont *getFont(int i) const;
105    FontFakery getFakery(int i) const;
106    unsigned int getGlyphId(int i) const;
107    float getX(int i) const;
108    float getY(int i) const;
109
110    float getAdvance() const;
111
112    // Get advances, copying into caller-provided buffer. The size of this
113    // buffer must match the length of the string (count arg to doLayout).
114    void getAdvances(float* advances);
115
116    // The i parameter is an offset within the buf relative to start, it is < count, where
117    // start and count are the parameters to doLayout
118    float getCharAdvance(size_t i) const { return mAdvances[i]; }
119
120    void getBounds(MinikinRect* rect);
121
122    // Purge all caches, useful in low memory conditions
123    static void purgeCaches();
124
125private:
126    friend class LayoutCacheKey;
127
128    // Find a face in the mFaces vector, or create a new entry
129    int findFace(FakedFont face, LayoutContext* ctx);
130
131    // Lay out a single bidi run
132    void doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
133        bool isRtl, LayoutContext* ctx, size_t dstStart);
134
135    // Lay out a single word
136    void doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
137        bool isRtl, LayoutContext* ctx, size_t bufStart);
138
139    // Lay out a single bidi run
140    void doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
141        bool isRtl, LayoutContext* ctx);
142
143    // Append another layout (for example, cached value) into this one
144    void appendLayout(Layout* src, size_t start);
145
146    std::vector<LayoutGlyph> mGlyphs;
147    std::vector<float> mAdvances;
148
149    const FontCollection* mCollection;
150    std::vector<FakedFont> mFaces;
151    float mAdvance;
152    MinikinRect mBounds;
153};
154
155}  // namespace android
156
157#endif  // MINIKIN_LAYOUT_H
158