Layout.h revision 86fa46c5ebb0d2c3319e08f4fbf487d8c2abbbfc
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/CssParse.h>
25#include <minikin/FontCollection.h>
26#include <minikin/MinikinFontFreeType.h>
27
28namespace android {
29
30// The Bitmap class is for debugging. We'll probably move it out
31// of here into a separate lightweight software rendering module
32// (optional, as we'd hope most clients would do their own)
33class Bitmap {
34public:
35    Bitmap(int width, int height);
36    ~Bitmap();
37    void writePnm(std::ofstream& o) const;
38    void drawGlyph(const GlyphBitmap& bitmap, int x, int y);
39private:
40    int width;
41    int height;
42    uint8_t* buf;
43};
44
45struct LayoutGlyph {
46    // index into mFaces and mHbFonts vectors. We could imagine
47    // moving this into a run length representation, because it's
48    // more efficient for long strings, and we'll probably need
49    // something like that for paint attributes (color, underline,
50    // fake b/i, etc), as having those per-glyph is bloated.
51    int font_ix;
52
53    unsigned int glyph_id;
54    float x;
55    float y;
56};
57
58// Lifecycle and threading assumptions for Layout:
59// The object is assumed to be owned by a single thread; multiple threads
60// may not mutate it at the same time.
61// The lifetime of the FontCollection set through setFontCollection must
62// extend through the lifetime of the Layout object.
63class Layout {
64public:
65    ~Layout();
66
67    void dump() const;
68    void setFontCollection(const FontCollection* collection);
69    void doLayout(const uint16_t* buf, size_t nchars);
70    void draw(Bitmap*, int x0, int y0) const;
71    void setProperties(const std::string css);
72
73    // This must be called before any invocations.
74	// TODO: probably have a factory instead
75    static void init();
76
77    // public accessors
78    size_t nGlyphs() const;
79    // Does not bump reference; ownership is still layout
80    MinikinFont *getFont(int i) const;
81    unsigned int getGlyphId(int i) const;
82    float getX(int i) const;
83    float getY(int i) const;
84
85    float getAdvance() const;
86
87    // Get advances, copying into caller-provided buffer. The size of this
88    // buffer must match the length of the string (nchars arg to doLayout).
89    void getAdvances(float* advances);
90
91    void getBounds(MinikinRect* rect);
92
93private:
94    // Find a face in the mFaces vector, or create a new entry
95    int findFace(MinikinFont* face, MinikinPaint* paint);
96
97    // Lay out a single bidi run
98    void doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
99        bool isRtl, FontStyle style, MinikinPaint& paint);
100
101    CssProperties mProps;  // TODO: want spans
102    std::vector<LayoutGlyph> mGlyphs;
103    std::vector<float> mAdvances;
104
105    // In future, this will be some kind of mapping from the
106    // identifier used to represent font-family to a font collection.
107    // But for the time being, it should be ok to have just one
108    // per layout.
109    const FontCollection* mCollection;
110    std::vector<MinikinFont *> mFaces;
111    std::vector<hb_font_t *> mHbFonts;
112    float mAdvance;
113    MinikinRect mBounds;
114};
115
116}  // namespace android
117
118#endif  // MINIKIN_LAYOUT_H
119