Layout.cpp revision 09f1901d6befcab49ed46cb77151a5d4af14a3b9 
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#define LOG_TAG "Minikin"
18#include <cutils/log.h>
19
20#include <string>
21#include <vector>
22#include <algorithm>
23#include <fstream>
24#include <iostream>  // for debugging
25#include <stdio.h>  // ditto
26
27#include <utils/JenkinsHash.h>
28#include <utils/LruCache.h>
29#include <utils/Singleton.h>
30#include <utils/String16.h>
31
32#include <unicode/ubidi.h>
33#include <hb-icu.h>
34
35#include "MinikinInternal.h"
36#include <minikin/MinikinFontFreeType.h>
37#include <minikin/Layout.h>
38
39using std::string;
40using std::vector;
41
42namespace android {
43
44// TODO: these should move into the header file, but for now we don't want
45// to cause namespace collisions with TextLayout.h
46enum {
47    kBidi_LTR = 0,
48    kBidi_RTL = 1,
49    kBidi_Default_LTR = 2,
50    kBidi_Default_RTL = 3,
51    kBidi_Force_LTR = 4,
52    kBidi_Force_RTL = 5,
53
54    kBidi_Mask = 0x7
55};
56
57const int kDirection_Mask = 0x1;
58
59// Layout cache datatypes
60
61class LayoutCacheKey {
62public:
63    LayoutCacheKey(const FontCollection* collection, const MinikinPaint& paint, FontStyle style,
64            const uint16_t* chars, size_t start, size_t count, size_t nchars, bool dir)
65            : mStart(start), mCount(count), mId(collection->getId()), mStyle(style),
66            mSize(paint.size), mScaleX(paint.scaleX), mSkewX(paint.skewX),
67            mLetterSpacing(paint.letterSpacing),
68            mPaintFlags(paint.paintFlags), mIsRtl(dir) {
69        mText.setTo(chars, nchars);
70    }
71    bool operator==(const LayoutCacheKey &other) const;
72    hash_t hash() const;
73
74    // This is present to avoid having to copy the text more than once.
75    const uint16_t* textBuf() { return mText.string(); }
76private:
77    String16 mText;
78    size_t mStart;
79    size_t mCount;
80    uint32_t mId;  // for the font collection
81    FontStyle mStyle;
82    float mSize;
83    float mScaleX;
84    float mSkewX;
85    float mLetterSpacing;
86    int32_t mPaintFlags;
87    bool mIsRtl;
88    // Note: any fields added to MinikinPaint must also be reflected here.
89    // TODO: language matching (possibly integrate into style)
90};
91
92class LayoutCache : private OnEntryRemoved<LayoutCacheKey, Layout*> {
93public:
94    LayoutCache() : mCache(kMaxEntries) {
95        mCache.setOnEntryRemovedListener(this);
96    }
97
98    // callback for OnEntryRemoved
99    void operator()(LayoutCacheKey& key, Layout*& value) {
100        delete value;
101    }
102
103    LruCache<LayoutCacheKey, Layout*> mCache;
104private:
105    //static const size_t kMaxEntries = LruCache<LayoutCacheKey, Layout*>::kUnlimitedCapacity;
106
107    // TODO: eviction based on memory footprint; for now, we just use a constant
108    // number of strings
109    static const size_t kMaxEntries = 5000;
110};
111
112class HbFaceCache : private OnEntryRemoved<int32_t, hb_face_t*> {
113public:
114    HbFaceCache() : mCache(kMaxEntries) {
115        mCache.setOnEntryRemovedListener(this);
116    }
117
118    // callback for OnEntryRemoved
119    void operator()(int32_t& key, hb_face_t*& value) {
120        hb_face_destroy(value);
121    }
122
123    LruCache<int32_t, hb_face_t*> mCache;
124private:
125    static const size_t kMaxEntries = 100;
126};
127
128class LayoutEngine : public Singleton<LayoutEngine> {
129public:
130    LayoutEngine() {
131        hbBuffer = hb_buffer_create();
132    }
133
134    hb_buffer_t* hbBuffer;
135    LayoutCache layoutCache;
136    HbFaceCache hbFaceCache;
137};
138
139ANDROID_SINGLETON_STATIC_INSTANCE(LayoutEngine);
140
141bool LayoutCacheKey::operator==(const LayoutCacheKey& other) const {
142    return mId == other.mId
143            && mStart == other.mStart
144            && mCount == other.mCount
145            && mStyle == other.mStyle
146            && mSize == other.mSize
147            && mScaleX == other.mScaleX
148            && mSkewX == other.mSkewX
149            && mLetterSpacing == other.mLetterSpacing
150            && mPaintFlags == other.mPaintFlags
151            && mIsRtl == other.mIsRtl
152            && mText == other.mText;
153}
154
155hash_t LayoutCacheKey::hash() const {
156    uint32_t hash = JenkinsHashMix(0, mId);
157    hash = JenkinsHashMix(hash, mStart);
158    hash = JenkinsHashMix(hash, mCount);
159    hash = JenkinsHashMix(hash, hash_type(mStyle));
160    hash = JenkinsHashMix(hash, hash_type(mSize));
161    hash = JenkinsHashMix(hash, hash_type(mScaleX));
162    hash = JenkinsHashMix(hash, hash_type(mSkewX));
163    hash = JenkinsHashMix(hash, hash_type(mLetterSpacing));
164    hash = JenkinsHashMix(hash, hash_type(mPaintFlags));
165    hash = JenkinsHashMix(hash, hash_type(mIsRtl));
166    hash = JenkinsHashMixShorts(hash, mText.string(), mText.size());
167    return JenkinsHashWhiten(hash);
168}
169
170struct LayoutContext {
171    MinikinPaint paint;
172    FontStyle style;
173    std::vector<hb_font_t*> hbFonts;  // parallel to mFaces
174};
175
176hash_t hash_type(const LayoutCacheKey& key) {
177    return key.hash();
178}
179
180Bitmap::Bitmap(int width, int height) : width(width), height(height) {
181    buf = new uint8_t[width * height]();
182}
183
184Bitmap::~Bitmap() {
185    delete[] buf;
186}
187
188void Bitmap::writePnm(std::ofstream &o) const {
189    o << "P5" << std::endl;
190    o << width << " " << height << std::endl;
191    o << "255" << std::endl;
192    o.write((const char *)buf, width * height);
193    o.close();
194}
195
196void Bitmap::drawGlyph(const GlyphBitmap& bitmap, int x, int y) {
197    int bmw = bitmap.width;
198    int bmh = bitmap.height;
199    x += bitmap.left;
200    y -= bitmap.top;
201    int x0 = std::max(0, x);
202    int x1 = std::min(width, x + bmw);
203    int y0 = std::max(0, y);
204    int y1 = std::min(height, y + bmh);
205    const unsigned char* src = bitmap.buffer + (y0 - y) * bmw + (x0 - x);
206    uint8_t* dst = buf + y0 * width;
207    for (int yy = y0; yy < y1; yy++) {
208        for (int xx = x0; xx < x1; xx++) {
209            int pixel = (int)dst[xx] + (int)src[xx - x];
210            pixel = pixel > 0xff ? 0xff : pixel;
211            dst[xx] = pixel;
212        }
213        src += bmw;
214        dst += width;
215    }
216}
217
218void MinikinRect::join(const MinikinRect& r) {
219    if (isEmpty()) {
220        set(r);
221    } else if (!r.isEmpty()) {
222        mLeft = std::min(mLeft, r.mLeft);
223        mTop = std::min(mTop, r.mTop);
224        mRight = std::max(mRight, r.mRight);
225        mBottom = std::max(mBottom, r.mBottom);
226    }
227}
228
229// TODO: the actual initialization is deferred, maybe make this explicit
230void Layout::init() {
231}
232
233void Layout::setFontCollection(const FontCollection* collection) {
234    mCollection = collection;
235}
236
237hb_blob_t* referenceTable(hb_face_t* face, hb_tag_t tag, void* userData)  {
238    MinikinFont* font = reinterpret_cast<MinikinFont*>(userData);
239    size_t length = 0;
240    bool ok = font->GetTable(tag, NULL, &length);
241    if (!ok) {
242        return 0;
243    }
244    char* buffer = reinterpret_cast<char*>(malloc(length));
245    if (!buffer) {
246        return 0;
247    }
248    ok = font->GetTable(tag, reinterpret_cast<uint8_t*>(buffer), &length);
249    printf("referenceTable %c%c%c%c length=%d %d\n",
250        (tag >>24) & 0xff, (tag>>16)&0xff, (tag>>8)&0xff, tag&0xff, length, ok);
251    if (!ok) {
252        free(buffer);
253        return 0;
254    }
255    return hb_blob_create(const_cast<char*>(buffer), length,
256        HB_MEMORY_MODE_WRITABLE, buffer, free);
257}
258
259static hb_bool_t harfbuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoint_t unicode, hb_codepoint_t variationSelector, hb_codepoint_t* glyph, void* userData)
260{
261    MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
262    MinikinFont* font = paint->font;
263    uint32_t glyph_id;
264    /* HarfBuzz replaces broken input codepoints with (unsigned int) -1.
265     * Skia expects valid Unicode.
266     * Replace invalid codepoints with U+FFFD REPLACEMENT CHARACTER.
267     */
268    if (unicode > 0x10FFFF)
269        unicode = 0xFFFD;
270    bool ok = font->GetGlyph(unicode, &glyph_id);
271    if (ok) {
272        *glyph = glyph_id;
273    }
274    return ok;
275}
276
277static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
278{
279    MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
280    MinikinFont* font = paint->font;
281    float advance = font->GetHorizontalAdvance(glyph, *paint);
282    return 256 * advance + 0.5;
283}
284
285static hb_bool_t harfbuzzGetGlyphHorizontalOrigin(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_position_t* x, hb_position_t* y, void* userData)
286{
287    // Just return true, following the way that Harfbuzz-FreeType
288    // implementation does.
289    return true;
290}
291
292hb_font_funcs_t* getHbFontFuncs() {
293    static hb_font_funcs_t* hbFontFuncs = 0;
294
295    if (hbFontFuncs == 0) {
296        hbFontFuncs = hb_font_funcs_create();
297        hb_font_funcs_set_glyph_func(hbFontFuncs, harfbuzzGetGlyph, 0, 0);
298        hb_font_funcs_set_glyph_h_advance_func(hbFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
299        hb_font_funcs_set_glyph_h_origin_func(hbFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
300        hb_font_funcs_make_immutable(hbFontFuncs);
301    }
302    return hbFontFuncs;
303}
304
305static hb_face_t* getHbFace(MinikinFont* minikinFont) {
306    HbFaceCache& cache = LayoutEngine::getInstance().hbFaceCache;
307    int32_t fontId = minikinFont->GetUniqueId();
308    hb_face_t* face = cache.mCache.get(fontId);
309    if (face == NULL) {
310        face = hb_face_create_for_tables(referenceTable, minikinFont, NULL);
311        cache.mCache.put(fontId, face);
312    }
313    return face;
314}
315
316static hb_font_t* create_hb_font(MinikinFont* minikinFont, MinikinPaint* minikinPaint) {
317    hb_face_t* face = getHbFace(minikinFont);
318    hb_font_t* font = hb_font_create(face);
319    hb_font_set_funcs(font, getHbFontFuncs(), minikinPaint, 0);
320    return font;
321}
322
323static float HBFixedToFloat(hb_position_t v)
324{
325    return scalbnf (v, -8);
326}
327
328static hb_position_t HBFloatToFixed(float v)
329{
330    return scalbnf (v, +8);
331}
332
333void Layout::dump() const {
334    for (size_t i = 0; i < mGlyphs.size(); i++) {
335        const LayoutGlyph& glyph = mGlyphs[i];
336        std::cout << glyph.glyph_id << ": " << glyph.x << ", " << glyph.y << std::endl;
337    }
338}
339
340int Layout::findFace(FakedFont face, LayoutContext* ctx) {
341    unsigned int ix;
342    for (ix = 0; ix < mFaces.size(); ix++) {
343        if (mFaces[ix].font == face.font) {
344            return ix;
345        }
346    }
347    mFaces.push_back(face);
348    // Note: ctx == NULL means we're copying from the cache, no need to create
349    // corresponding hb_font object.
350    if (ctx != NULL) {
351        hb_font_t* font = create_hb_font(face.font, &ctx->paint);
352        ctx->hbFonts.push_back(font);
353    }
354    return ix;
355}
356
357static FontStyle styleFromCss(const CssProperties &props) {
358    int weight = 4;
359    if (props.hasTag(fontWeight)) {
360        weight = props.value(fontWeight).getIntValue() / 100;
361    }
362    bool italic = false;
363    if (props.hasTag(fontStyle)) {
364        italic = props.value(fontStyle).getIntValue() != 0;
365    }
366    FontLanguage lang;
367    if (props.hasTag(cssLang)) {
368        string langStr = props.value(cssLang).getStringValue();
369        lang = FontLanguage(langStr.c_str(), langStr.size());
370    }
371    int variant = 0;
372    if (props.hasTag(minikinVariant)) {
373        variant = props.value(minikinVariant).getIntValue();
374    }
375    return FontStyle(lang, variant, weight, italic);
376}
377
378static hb_script_t codePointToScript(hb_codepoint_t codepoint) {
379    static hb_unicode_funcs_t* u = 0;
380    if (!u) {
381        u = hb_icu_get_unicode_funcs();
382    }
383    return hb_unicode_script(u, codepoint);
384}
385
386static hb_codepoint_t decodeUtf16(const uint16_t* chars, size_t len, ssize_t* iter) {
387    const uint16_t v = chars[(*iter)++];
388    // test whether v in (0xd800..0xdfff), lead or trail surrogate
389    if ((v & 0xf800) == 0xd800) {
390        // test whether v in (0xd800..0xdbff), lead surrogate
391        if (size_t(*iter) < len && (v & 0xfc00) == 0xd800) {
392            const uint16_t v2 = chars[(*iter)++];
393            // test whether v2 in (0xdc00..0xdfff), trail surrogate
394            if ((v2 & 0xfc00) == 0xdc00) {
395                // (0xd800 0xdc00) in utf-16 maps to 0x10000 in ucs-32
396                const hb_codepoint_t delta = (0xd800 << 10) + 0xdc00 - 0x10000;
397                return (((hb_codepoint_t)v) << 10) + v2 - delta;
398            }
399            (*iter) -= 1;
400            return 0xFFFDu;
401        } else {
402            return 0xFFFDu;
403        }
404    } else {
405        return v;
406    }
407}
408
409static hb_script_t getScriptRun(const uint16_t* chars, size_t len, ssize_t* iter) {
410    if (size_t(*iter) == len) {
411        return HB_SCRIPT_UNKNOWN;
412    }
413    uint32_t cp = decodeUtf16(chars, len, iter);
414    hb_script_t current_script = codePointToScript(cp);
415    for (;;) {
416        if (size_t(*iter) == len)
417            break;
418        const ssize_t prev_iter = *iter;
419        cp = decodeUtf16(chars, len, iter);
420        const hb_script_t script = codePointToScript(cp);
421        if (script != current_script) {
422            if (current_script == HB_SCRIPT_INHERITED ||
423                current_script == HB_SCRIPT_COMMON) {
424                current_script = script;
425            } else if (script == HB_SCRIPT_INHERITED ||
426                script == HB_SCRIPT_COMMON) {
427                continue;
428            } else {
429                *iter = prev_iter;
430                break;
431            }
432        }
433    }
434    if (current_script == HB_SCRIPT_INHERITED) {
435        current_script = HB_SCRIPT_COMMON;
436    }
437
438    return current_script;
439}
440
441/**
442 * For the purpose of layout, a word break is a boundary with no
443 * kerning or complex script processing. This is necessarily a
444 * heuristic, but should be accurate most of the time.
445 */
446static bool isWordBreak(int c) {
447    if (c == ' ' || (c >= 0x2000 && c <= 0x200a) || c == 0x3000) {
448        // spaces
449        return true;
450    }
451    if ((c >= 0x3400 && c <= 0x9fff)) {
452        // CJK ideographs (and yijing hexagram symbols)
453        return true;
454    }
455    // Note: kana is not included, as sophisticated fonts may kern kana
456    return false;
457}
458
459/**
460 * Return offset of previous word break. It is either < offset or == 0.
461 */
462static size_t getPrevWordBreak(const uint16_t* chars, size_t offset) {
463    if (offset == 0) return 0;
464    if (isWordBreak(chars[offset - 1])) {
465        return offset - 1;
466    }
467    for (size_t i = offset - 1; i > 0; i--) {
468        if (isWordBreak(chars[i - 1])) {
469            return i;
470        }
471    }
472    return 0;
473}
474
475/**
476 * Return offset of next word break. It is either > offset or == len.
477 */
478static size_t getNextWordBreak(const uint16_t* chars, size_t offset, size_t len) {
479    if (offset >= len) return len;
480    if (isWordBreak(chars[offset])) {
481        return offset + 1;
482    }
483    for (size_t i = offset + 1; i < len; i++) {
484        if (isWordBreak(chars[i])) {
485            return i;
486        }
487    }
488    return len;
489}
490
491static void clearHbFonts(LayoutContext* ctx) {
492    for (size_t i = 0; i < ctx->hbFonts.size(); i++) {
493        hb_font_destroy(ctx->hbFonts[i]);
494    }
495    ctx->hbFonts.clear();
496}
497
498void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
499        const string& css) {
500
501    CssProperties props;
502    props.parse(css);
503
504    FontStyle style = styleFromCss(props);
505    MinikinPaint paint;
506
507    paint.size = props.value(fontSize).getDoubleValue();
508    paint.scaleX = props.hasTag(fontScaleX)
509            ? props.value(fontScaleX).getDoubleValue() : 1;
510    paint.skewX = props.hasTag(fontSkewX)
511            ? props.value(fontSkewX).getDoubleValue() : 0;
512    paint.letterSpacing = props.hasTag(letterSpacing)
513            ? props.value(letterSpacing).getDoubleValue() : 0;
514    paint.paintFlags = props.hasTag(paintFlags)
515            ? props.value(paintFlags).getUintValue() : 0;
516
517    int bidiFlags = props.hasTag(minikinBidi) ? props.value(minikinBidi).getIntValue() : 0;
518
519    doLayout(buf, start, count, bufSize, bidiFlags, style, paint);
520}
521
522void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
523        int bidiFlags, const FontStyle &style, const MinikinPaint &paint) {
524    AutoMutex _l(gMinikinLock);
525
526    LayoutContext ctx;
527    ctx.style = style;
528    ctx.paint = paint;
529
530    bool isRtl = (bidiFlags & kDirection_Mask) != 0;
531    bool doSingleRun = true;
532
533    mGlyphs.clear();
534    mFaces.clear();
535    mBounds.setEmpty();
536    mAdvances.clear();
537    mAdvances.resize(count, 0);
538    mAdvance = 0;
539    if (!(bidiFlags == kBidi_Force_LTR || bidiFlags == kBidi_Force_RTL)) {
540        UBiDi* bidi = ubidi_open();
541        if (bidi) {
542            UErrorCode status = U_ZERO_ERROR;
543            UBiDiLevel bidiReq = bidiFlags;
544            if (bidiFlags == kBidi_Default_LTR) {
545                bidiReq = UBIDI_DEFAULT_LTR;
546            } else if (bidiFlags == kBidi_Default_RTL) {
547                bidiReq = UBIDI_DEFAULT_RTL;
548            }
549            ubidi_setPara(bidi, buf, bufSize, bidiReq, NULL, &status);
550            if (U_SUCCESS(status)) {
551                int paraDir = ubidi_getParaLevel(bidi) & kDirection_Mask;
552                ssize_t rc = ubidi_countRuns(bidi, &status);
553                if (!U_SUCCESS(status) || rc < 0) {
554                    ALOGW("error counting bidi runs, status = %d", status);
555                }
556                if (!U_SUCCESS(status) || rc <= 1) {
557                    isRtl = (paraDir == kBidi_RTL);
558                } else {
559                    doSingleRun = false;
560                    // iterate through runs
561                    for (ssize_t i = 0; i < (ssize_t)rc; i++) {
562                        int32_t startRun = -1;
563                        int32_t lengthRun = -1;
564                        UBiDiDirection runDir = ubidi_getVisualRun(bidi, i, &startRun, &lengthRun);
565                        if (startRun == -1 || lengthRun == -1) {
566                            ALOGE("invalid visual run");
567                            // skip the invalid run
568                            continue;
569                        }
570                        int32_t endRun = std::min(startRun + lengthRun, int32_t(start + count));
571                        startRun = std::max(startRun, int32_t(start));
572                        lengthRun = endRun - startRun;
573                        if (lengthRun > 0) {
574                            isRtl = (runDir == UBIDI_RTL);
575                            doLayoutRunCached(buf, startRun, lengthRun, bufSize, isRtl, &ctx,
576                                start);
577                        }
578                    }
579                }
580            } else {
581                ALOGE("error calling ubidi_setPara, status = %d", status);
582            }
583            ubidi_close(bidi);
584        } else {
585            ALOGE("error creating bidi object");
586        }
587    }
588    if (doSingleRun) {
589        doLayoutRunCached(buf, start, count, bufSize, isRtl, &ctx, start);
590    }
591    clearHbFonts(&ctx);
592}
593
594void Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
595        bool isRtl, LayoutContext* ctx, size_t dstStart) {
596    if (!isRtl) {
597        // left to right
598        size_t wordstart = start == bufSize ? start : getPrevWordBreak(buf, start + 1);
599        size_t wordend;
600        for (size_t iter = start; iter < start + count; iter = wordend) {
601            wordend = getNextWordBreak(buf, iter, bufSize);
602            size_t wordcount = std::min(start + count, wordend) - iter;
603            doLayoutWord(buf + wordstart, iter - wordstart, wordcount, wordend - wordstart,
604                    isRtl, ctx, iter - dstStart);
605            wordstart = wordend;
606        }
607    } else {
608        // right to left
609        size_t wordstart;
610        size_t end = start + count;
611        size_t wordend = end == 0 ? 0 : getNextWordBreak(buf, end - 1, bufSize);
612        for (size_t iter = end; iter > start; iter = wordstart) {
613            wordstart = getPrevWordBreak(buf, iter);
614            size_t bufStart = std::max(start, wordstart);
615            doLayoutWord(buf + wordstart, bufStart - wordstart, iter - bufStart,
616                    wordend - wordstart, isRtl, ctx, bufStart - dstStart);
617            wordend = wordstart;
618        }
619    }
620}
621
622void Layout::doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
623        bool isRtl, LayoutContext* ctx, size_t bufStart) {
624    LayoutCache& cache = LayoutEngine::getInstance().layoutCache;
625    LayoutCacheKey key(mCollection, ctx->paint, ctx->style, buf, start, count, bufSize, isRtl);
626    Layout* value = cache.mCache.get(key);
627    if (value == NULL) {
628        value = new Layout();
629        value->setFontCollection(mCollection);
630        value->mAdvances.resize(count, 0);
631        clearHbFonts(ctx);
632        // Note: we do the layout from the copy stored in the key, in case a
633        // badly-behaved client is mutating the buffer in a separate thread.
634        value->doLayoutRun(key.textBuf(), start, count, bufSize, isRtl, ctx);
635    }
636    appendLayout(value, bufStart);
637    cache.mCache.put(key, value);
638}
639
640static void addFeatures(vector<hb_feature_t>* features) {
641    // hardcoded features, to be repaced with more flexible configuration
642    static hb_feature_t palt = { HB_TAG('p', 'a', 'l', 't'), 1, 0, ~0u };
643
644    // Don't enable "palt" for now, pending implementation of more of the
645    // W3C Japanese layout recommendations. See:
646    // http://www.w3.org/TR/2012/NOTE-jlreq-20120403/
647#if 0
648    features->push_back(palt);
649#endif
650}
651
652void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
653        bool isRtl, LayoutContext* ctx) {
654    hb_buffer_t* buffer = LayoutEngine::getInstance().hbBuffer;
655    vector<FontCollection::Run> items;
656    mCollection->itemize(buf + start, count, ctx->style, &items);
657    if (isRtl) {
658        std::reverse(items.begin(), items.end());
659    }
660
661    vector<hb_feature_t> features;
662    // Disable default-on non-required ligature features if letter-spacing
663    // See http://dev.w3.org/csswg/css-text-3/#letter-spacing-property
664    // "When the effective spacing between two characters is not zero (due to
665    // either justification or a non-zero value of letter-spacing), user agents
666    // should not apply optional ligatures."
667    if (fabs(ctx->paint.letterSpacing) > 0.03)
668    {
669        static const hb_feature_t no_liga = { HB_TAG('l', 'i', 'g', 'a'), 0, 0, ~0u };
670        static const hb_feature_t no_clig = { HB_TAG('c', 'l', 'i', 'g'), 0, 0, ~0u };
671        features.push_back(no_liga);
672        features.push_back(no_clig);
673    }
674    addFeatures(&features);
675
676    double size = ctx->paint.size;
677    double scaleX = ctx->paint.scaleX;
678    double letterSpace = ctx->paint.letterSpacing * size * scaleX;
679    double letterSpaceHalf = letterSpace * .5;
680
681    float x = mAdvance;
682    float y = 0;
683    for (size_t run_ix = 0; run_ix < items.size(); run_ix++) {
684        FontCollection::Run &run = items[run_ix];
685        if (run.fakedFont.font == NULL) {
686            ALOGE("no font for run starting u+%04x length %d", buf[run.start], run.end - run.start);
687            continue;
688        }
689        int font_ix = findFace(run.fakedFont, ctx);
690        ctx->paint.font = mFaces[font_ix].font;
691        ctx->paint.fakery = mFaces[font_ix].fakery;
692        hb_font_t* hbFont = ctx->hbFonts[font_ix];
693#ifdef VERBOSE
694        std::cout << "Run " << run_ix << ", font " << font_ix <<
695            " [" << run.start << ":" << run.end << "]" << std::endl;
696#endif
697
698        hb_font_set_ppem(hbFont, size * scaleX, size);
699        hb_font_set_scale(hbFont, HBFloatToFixed(size * scaleX), HBFloatToFixed(size));
700
701        // TODO: if there are multiple scripts within a font in an RTL run,
702        // we need to reorder those runs. This is unlikely with our current
703        // font stack, but should be done for correctness.
704        ssize_t srunend;
705        for (ssize_t srunstart = run.start; srunstart < run.end; srunstart = srunend) {
706            srunend = srunstart;
707            hb_script_t script = getScriptRun(buf + start, run.end, &srunend);
708
709            hb_buffer_reset(buffer);
710            hb_buffer_set_script(buffer, script);
711            hb_buffer_set_direction(buffer, isRtl? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
712            FontLanguage language = ctx->style.getLanguage();
713            if (language) {
714                string lang = language.getString();
715                hb_buffer_set_language(buffer, hb_language_from_string(lang.c_str(), -1));
716            }
717            hb_buffer_add_utf16(buffer, buf, bufSize, srunstart + start, srunend - srunstart);
718            hb_shape(hbFont, buffer, features.empty() ? NULL : &features[0], features.size());
719            unsigned int numGlyphs;
720            hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, &numGlyphs);
721            hb_glyph_position_t* positions = hb_buffer_get_glyph_positions(buffer, NULL);
722            if (numGlyphs)
723            {
724                mAdvances[info[0].cluster - start] += letterSpaceHalf;
725                x += letterSpaceHalf;
726            }
727            for (unsigned int i = 0; i < numGlyphs; i++) {
728    #ifdef VERBOSE
729                std::cout << positions[i].x_advance << " " << positions[i].y_advance << " " << positions[i].x_offset << " " << positions[i].y_offset << std::endl;            std::cout << "DoLayout " << info[i].codepoint <<
730                ": " << HBFixedToFloat(positions[i].x_advance) << "; " << positions[i].x_offset << ", " << positions[i].y_offset << std::endl;
731    #endif
732                if (i > 0 && info[i - 1].cluster != info[i].cluster) {
733                    mAdvances[info[i - 1].cluster - start] += letterSpaceHalf;
734                    mAdvances[info[i].cluster - start] += letterSpaceHalf;
735                    x += letterSpaceHalf;
736                }
737
738                hb_codepoint_t glyph_ix = info[i].codepoint;
739                float xoff = HBFixedToFloat(positions[i].x_offset);
740                float yoff = -HBFixedToFloat(positions[i].y_offset);
741                xoff += yoff * ctx->paint.skewX;
742                LayoutGlyph glyph = {font_ix, glyph_ix, x + xoff, y + yoff};
743                mGlyphs.push_back(glyph);
744                float xAdvance = HBFixedToFloat(positions[i].x_advance);
745                MinikinRect glyphBounds;
746                ctx->paint.font->GetBounds(&glyphBounds, glyph_ix, ctx->paint);
747                glyphBounds.offset(x + xoff, y + yoff);
748                mBounds.join(glyphBounds);
749                mAdvances[info[i].cluster - start] += xAdvance;
750                x += xAdvance;
751            }
752            if (numGlyphs)
753            {
754                mAdvances[info[numGlyphs - 1].cluster - start] += letterSpaceHalf;
755                x += letterSpaceHalf;
756            }
757        }
758    }
759    mAdvance = x;
760}
761
762void Layout::appendLayout(Layout* src, size_t start) {
763    // Note: size==1 is by far most common, should have specialized vector for this
764    std::vector<int> fontMap;
765    for (size_t i = 0; i < src->mFaces.size(); i++) {
766        int font_ix = findFace(src->mFaces[i], NULL);
767        fontMap.push_back(font_ix);
768    }
769    int x0 = mAdvance;
770    for (size_t i = 0; i < src->mGlyphs.size(); i++) {
771        LayoutGlyph& srcGlyph = src->mGlyphs[i];
772        int font_ix = fontMap[srcGlyph.font_ix];
773        unsigned int glyph_id = srcGlyph.glyph_id;
774        float x = x0 + srcGlyph.x;
775        float y = srcGlyph.y;
776        LayoutGlyph glyph = {font_ix, glyph_id, x, y};
777        mGlyphs.push_back(glyph);
778    }
779    for (size_t i = 0; i < src->mAdvances.size(); i++) {
780        mAdvances[i + start] = src->mAdvances[i];
781    }
782    MinikinRect srcBounds(src->mBounds);
783    srcBounds.offset(x0, 0);
784    mBounds.join(srcBounds);
785    mAdvance += src->mAdvance;
786}
787
788void Layout::draw(Bitmap* surface, int x0, int y0, float size) const {
789    /*
790    TODO: redo as MinikinPaint settings
791    if (mProps.hasTag(minikinHinting)) {
792        int hintflags = mProps.value(minikinHinting).getIntValue();
793        if (hintflags & 1) load_flags |= FT_LOAD_NO_HINTING;
794        if (hintflags & 2) load_flags |= FT_LOAD_NO_AUTOHINT;
795    }
796    */
797    for (size_t i = 0; i < mGlyphs.size(); i++) {
798        const LayoutGlyph& glyph = mGlyphs[i];
799        MinikinFont* mf = mFaces[glyph.font_ix].font;
800        MinikinFontFreeType* face = static_cast<MinikinFontFreeType*>(mf);
801        GlyphBitmap glyphBitmap;
802        MinikinPaint paint;
803        paint.size = size;
804        bool ok = face->Render(glyph.glyph_id, paint, &glyphBitmap);
805        printf("glyphBitmap.width=%d, glyphBitmap.height=%d (%d, %d) x=%f, y=%f, ok=%d\n",
806            glyphBitmap.width, glyphBitmap.height, glyphBitmap.left, glyphBitmap.top, glyph.x, glyph.y, ok);
807        if (ok) {
808            surface->drawGlyph(glyphBitmap,
809                x0 + int(floor(glyph.x + 0.5)), y0 + int(floor(glyph.y + 0.5)));
810        }
811    }
812}
813
814size_t Layout::nGlyphs() const {
815    return mGlyphs.size();
816}
817
818MinikinFont* Layout::getFont(int i) const {
819    const LayoutGlyph& glyph = mGlyphs[i];
820    return mFaces[glyph.font_ix].font;
821}
822
823FontFakery Layout::getFakery(int i) const {
824    const LayoutGlyph& glyph = mGlyphs[i];
825    return mFaces[glyph.font_ix].fakery;
826}
827
828unsigned int Layout::getGlyphId(int i) const {
829    const LayoutGlyph& glyph = mGlyphs[i];
830    return glyph.glyph_id;
831}
832
833float Layout::getX(int i) const {
834    const LayoutGlyph& glyph = mGlyphs[i];
835    return glyph.x;
836}
837
838float Layout::getY(int i) const {
839    const LayoutGlyph& glyph = mGlyphs[i];
840    return glyph.y;
841}
842
843float Layout::getAdvance() const {
844    return mAdvance;
845}
846
847void Layout::getAdvances(float* advances) {
848    memcpy(advances, &mAdvances[0], mAdvances.size() * sizeof(float));
849}
850
851void Layout::getBounds(MinikinRect* bounds) {
852    bounds->set(mBounds);
853}
854
855void Layout::purgeCaches() {
856    AutoMutex _l(gMinikinLock);
857    LayoutCache& layoutCache = LayoutEngine::getInstance().layoutCache;
858    layoutCache.mCache.clear();
859    HbFaceCache& hbCache = LayoutEngine::getInstance().hbFaceCache;
860    hbCache.mCache.clear();
861}
862
863}  // namespace android
864