TextLayoutCache.h revision bd901dee317d10c6a921922c3d7d788b90306c82 
1/*
2 * Copyright (C) 2011 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 ANDROID_TEXT_LAYOUT_CACHE_H
18#define ANDROID_TEXT_LAYOUT_CACHE_H
19
20#include "RtlProperties.h"
21
22#include <stddef.h>
23#include <utils/threads.h>
24#include <utils/String16.h>
25#include <utils/GenerationCache.h>
26#include <utils/KeyedVector.h>
27#include <utils/Compare.h>
28#include <utils/RefBase.h>
29#include <utils/Singleton.h>
30
31#include <SkPaint.h>
32#include <SkTemplates.h>
33#include <SkUtils.h>
34#include <SkAutoKern.h>
35
36#include <unicode/ubidi.h>
37#include <unicode/ushape.h>
38#include <unicode/unistr.h>
39
40#include "HarfbuzzSkia.h"
41#include "harfbuzz-shaper.h"
42
43#include <android_runtime/AndroidRuntime.h>
44
45#define UNICODE_NOT_A_CHAR              0xffff
46#define UNICODE_ZWSP                    0x200b
47#define UNICODE_FIRST_LOW_SURROGATE     0xdc00
48#define UNICODE_FIRST_HIGH_SURROGATE    0xd800
49#define UNICODE_FIRST_PRIVATE_USE       0xe000
50#define UNICODE_FIRST_RTL_CHAR          0x0590
51
52// Temporary buffer size
53#define CHAR_BUFFER_SIZE 80
54
55// Converts a number of mega-bytes into bytes
56#define MB(s) s * 1024 * 1024
57
58// Define the default cache size in Mb
59#define DEFAULT_TEXT_LAYOUT_CACHE_SIZE_IN_MB 0.250f
60
61// Define the interval in number of cache hits between two statistics dump
62#define DEFAULT_DUMP_STATS_CACHE_HIT_INTERVAL 100
63
64namespace android {
65
66/**
67 * TextLayoutCacheKey is the Cache key
68 */
69class TextLayoutCacheKey {
70public:
71    TextLayoutCacheKey();
72
73    TextLayoutCacheKey(const SkPaint* paint, const UChar* text, size_t start, size_t count,
74            size_t contextCount, int dirFlags);
75
76    TextLayoutCacheKey(const TextLayoutCacheKey& other);
77
78    /**
79     * We need to copy the text when we insert the key into the cache itself.
80     * We don't need to copy the text when we are only comparing keys.
81     */
82    void internalTextCopy();
83
84    /**
85     * Get the size of the Cache key.
86     */
87    size_t getSize() const;
88
89    static int compare(const TextLayoutCacheKey& lhs, const TextLayoutCacheKey& rhs);
90
91private:
92    const UChar* text; // if text is NULL, use textCopy
93    String16 textCopy;
94    size_t start;
95    size_t count;
96    size_t contextCount;
97    int dirFlags;
98    SkTypeface* typeface;
99    SkScalar textSize;
100    SkScalar textSkewX;
101    SkScalar textScaleX;
102    uint32_t flags;
103    SkPaint::Hinting hinting;
104
105    inline const UChar* getText() const { return text ? text : textCopy.string(); }
106
107}; // TextLayoutCacheKey
108
109inline int strictly_order_type(const TextLayoutCacheKey& lhs, const TextLayoutCacheKey& rhs) {
110    return TextLayoutCacheKey::compare(lhs, rhs) < 0;
111}
112
113inline int compare_type(const TextLayoutCacheKey& lhs, const TextLayoutCacheKey& rhs) {
114    return TextLayoutCacheKey::compare(lhs, rhs);
115}
116
117/*
118 * TextLayoutCacheValue is the Cache value
119 */
120class TextLayoutCacheValue : public RefBase {
121public:
122    TextLayoutCacheValue(size_t contextCount);
123
124    void setElapsedTime(uint32_t time);
125    uint32_t getElapsedTime();
126
127    inline const jfloat* getAdvances() const { return mAdvances.array(); }
128    inline size_t getAdvancesCount() const { return mAdvances.size(); }
129    inline jfloat getTotalAdvance() const { return mTotalAdvance; }
130    inline const jchar* getGlyphs() const { return mGlyphs.array(); }
131    inline size_t getGlyphsCount() const { return mGlyphs.size(); }
132
133    /**
134     * Advances vector
135     */
136    Vector<jfloat> mAdvances;
137
138    /**
139     * Total number of advances
140     */
141    jfloat mTotalAdvance;
142
143    /**
144     * Glyphs vector
145     */
146    Vector<jchar> mGlyphs;
147
148    /**
149     * Get the size of the Cache entry
150     */
151    size_t getSize() const;
152
153private:
154    /**
155     * Time for computing the values (in milliseconds)
156     */
157    uint32_t mElapsedTime;
158
159}; // TextLayoutCacheValue
160
161/**
162 * Cache of text layout information.
163 */
164class TextLayoutCache : public OnEntryRemoved<TextLayoutCacheKey, sp<TextLayoutCacheValue> >,
165        public Singleton<TextLayoutCache>
166{
167public:
168    TextLayoutCache();
169
170    virtual ~TextLayoutCache();
171
172    bool isInitialized() {
173        return mInitialized;
174    }
175
176    /**
177     * Used as a callback when an entry is removed from the cache
178     * Do not invoke directly
179     */
180    void operator()(TextLayoutCacheKey& text, sp<TextLayoutCacheValue>& desc);
181
182    sp<TextLayoutCacheValue> getValue(const SkPaint* paint, const jchar* text, jint start, jint count,
183            jint contextCount, jint dirFlags);
184
185    /**
186     * Clear the cache
187     */
188    void clear();
189
190private:
191    Mutex mLock;
192    bool mInitialized;
193
194    GenerationCache<TextLayoutCacheKey, sp<TextLayoutCacheValue> > mCache;
195
196    uint32_t mSize;
197    uint32_t mMaxSize;
198
199    uint32_t mCacheHitCount;
200    uint64_t mNanosecondsSaved;
201
202    uint64_t mCacheStartTime;
203
204    RtlDebugLevel mDebugLevel;
205    bool mDebugEnabled;
206
207    /*
208     * Class initialization
209     */
210    void init();
211
212    /**
213     * Dump Cache statistics
214     */
215    void dumpCacheStats();
216
217}; // TextLayoutCache
218
219/**
220 * The TextLayoutEngine is responsible for shaping with Harfbuzz library
221 */
222class TextLayoutEngine : public Singleton<TextLayoutEngine> {
223public:
224    TextLayoutEngine();
225    virtual ~TextLayoutEngine();
226
227    void computeValues(TextLayoutCacheValue* value, const SkPaint* paint, const UChar* chars,
228            size_t start, size_t count, size_t contextCount, int dirFlags);
229
230private:
231    /**
232     * Harfbuzz shaper item
233     */
234    HB_ShaperItem mShaperItem;
235
236    /**
237     * Harfbuzz font
238     */
239    HB_FontRec mFontRec;
240
241    /**
242     * Skia Paint used for shaping
243     */
244    SkPaint mShapingPaint;
245
246    /**
247     * Skia typefaces cached for shaping
248     */
249    SkTypeface* mDefaultTypeface;
250    SkTypeface* mArabicTypeface;
251    SkTypeface* mHebrewRegularTypeface;
252    SkTypeface* mHebrewBoldTypeface;
253    SkTypeface* mBengaliTypeface;
254    SkTypeface* mThaiTypeface;
255
256    /**
257     * Cache of Harfbuzz faces
258     */
259    KeyedVector<SkFontID, HB_Face> mCachedHBFaces;
260
261    /**
262     * Cache of glyph array size
263     */
264    size_t mShaperItemGlyphArraySize;
265
266    /**
267     * Buffer for containing the ICU normalized form of a run
268     */
269    UnicodeString mNormalizedString;
270
271    /**
272     * Buffer for normalizing a piece of a run with ICU
273     */
274    UnicodeString mBuffer;
275
276    size_t shapeFontRun(const SkPaint* paint, bool isRTL);
277
278    void computeValues(const SkPaint* paint, const UChar* chars,
279            size_t start, size_t count, size_t contextCount, int dirFlags,
280            Vector<jfloat>* const outAdvances, jfloat* outTotalAdvance,
281            Vector<jchar>* const outGlyphs);
282
283    void computeRunValues(const SkPaint* paint, const UChar* chars,
284            size_t count, bool isRTL,
285            Vector<jfloat>* const outAdvances, jfloat* outTotalAdvance,
286            Vector<jchar>* const outGlyphs);
287
288    SkTypeface* getCachedTypeface(SkTypeface** typeface, const char path[]);
289    HB_Face getCachedHBFace(SkTypeface* typeface);
290
291    void ensureShaperItemGlyphArrays(size_t size);
292    void createShaperItemGlyphArrays(size_t size);
293    void deleteShaperItemGlyphArrays();
294
295}; // TextLayoutEngine
296
297
298} // namespace android
299#endif /* ANDROID_TEXT_LAYOUT_CACHE_H */
300
301