Layout.cpp revision e8b4a1b78a29878c89659860a7b7fa5605b3be0e 
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 <math.h>
21#include <stdio.h>  // for debugging
22
23#include <algorithm>
24#include <fstream>
25#include <iostream>  // for debugging
26#include <string>
27#include <vector>
28
29#include <utils/JenkinsHash.h>
30#include <utils/LruCache.h>
31#include <utils/Singleton.h>
32#include <utils/String16.h>
33
34#include <unicode/ubidi.h>
35#include <hb-icu.h>
36
37#include "MinikinInternal.h"
38#include <minikin/MinikinFontFreeType.h>
39#include <minikin/Layout.h>
40
41using std::string;
42using std::vector;
43
44namespace android {
45
46// TODO: these should move into the header file, but for now we don't want
47// to cause namespace collisions with TextLayout.h
48enum {
49    kBidi_LTR = 0,
50    kBidi_RTL = 1,
51    kBidi_Default_LTR = 2,
52    kBidi_Default_RTL = 3,
53    kBidi_Force_LTR = 4,
54    kBidi_Force_RTL = 5,
55
56    kBidi_Mask = 0x7
57};
58
59const int kDirection_Mask = 0x1;
60
61struct LayoutContext {
62    MinikinPaint paint;
63    FontStyle style;
64    std::vector<hb_font_t*> hbFonts;  // parallel to mFaces
65
66    void clearHbFonts() {
67        for (size_t i = 0; i < hbFonts.size(); i++) {
68            hb_font_destroy(hbFonts[i]);
69        }
70        hbFonts.clear();
71    }
72};
73
74// Layout cache datatypes
75
76class LayoutCacheKey {
77public:
78    LayoutCacheKey(const FontCollection* collection, const MinikinPaint& paint, FontStyle style,
79            const uint16_t* chars, size_t start, size_t count, size_t nchars, bool dir)
80            : mStart(start), mCount(count), mId(collection->getId()), mStyle(style),
81            mSize(paint.size), mScaleX(paint.scaleX), mSkewX(paint.skewX),
82            mLetterSpacing(paint.letterSpacing),
83            mPaintFlags(paint.paintFlags), mIsRtl(dir),
84            mChars(chars), mNchars(nchars) {
85    }
86    bool operator==(const LayoutCacheKey &other) const;
87    hash_t hash() const;
88
89    void copyText() {
90        uint16_t* charsCopy = new uint16_t[mNchars];
91        memcpy(charsCopy, mChars, mNchars * sizeof(uint16_t));
92        mChars = charsCopy;
93    }
94    void freeText() {
95        delete[] mChars;
96        mChars = NULL;
97    }
98
99    void doLayout(Layout* layout, LayoutContext* ctx, const FontCollection* collection) const {
100        layout->setFontCollection(collection);
101        layout->mAdvances.resize(mCount, 0);
102        ctx->clearHbFonts();
103        layout->doLayoutRun(mChars, mStart, mCount, mNchars, mIsRtl, ctx);
104    }
105
106private:
107    const uint16_t* mChars;
108    size_t mNchars;
109    size_t mStart;
110    size_t mCount;
111    uint32_t mId;  // for the font collection
112    FontStyle mStyle;
113    float mSize;
114    float mScaleX;
115    float mSkewX;
116    float mLetterSpacing;
117    int32_t mPaintFlags;
118    bool mIsRtl;
119    // Note: any fields added to MinikinPaint must also be reflected here.
120    // TODO: language matching (possibly integrate into style)
121};
122
123class LayoutCache : private OnEntryRemoved<LayoutCacheKey, Layout*> {
124public:
125    LayoutCache() : mCache(kMaxEntries) {
126        mCache.setOnEntryRemovedListener(this);
127    }
128
129    void clear() {
130        mCache.clear();
131    }
132
133    Layout* get(LayoutCacheKey& key, LayoutContext* ctx, const FontCollection* collection) {
134        Layout* layout = mCache.get(key);
135        if (layout == NULL) {
136            key.copyText();
137            layout = new Layout();
138            key.doLayout(layout, ctx, collection);
139            mCache.put(key, layout);
140        }
141        return layout;
142    }
143
144private:
145    // callback for OnEntryRemoved
146    void operator()(LayoutCacheKey& key, Layout*& value) {
147        key.freeText();
148        delete value;
149    }
150
151    LruCache<LayoutCacheKey, Layout*> mCache;
152
153    //static const size_t kMaxEntries = LruCache<LayoutCacheKey, Layout*>::kUnlimitedCapacity;
154
155    // TODO: eviction based on memory footprint; for now, we just use a constant
156    // number of strings
157    static const size_t kMaxEntries = 5000;
158};
159
160class HbFaceCache : private OnEntryRemoved<int32_t, hb_face_t*> {
161public:
162    HbFaceCache() : mCache(kMaxEntries) {
163        mCache.setOnEntryRemovedListener(this);
164    }
165
166    // callback for OnEntryRemoved
167    void operator()(int32_t& key, hb_face_t*& value) {
168        hb_face_destroy(value);
169    }
170
171    LruCache<int32_t, hb_face_t*> mCache;
172private:
173    static const size_t kMaxEntries = 100;
174};
175
176class LayoutEngine : public Singleton<LayoutEngine> {
177public:
178    LayoutEngine() {
179        hbBuffer = hb_buffer_create();
180    }
181
182    hb_buffer_t* hbBuffer;
183    LayoutCache layoutCache;
184    HbFaceCache hbFaceCache;
185};
186
187ANDROID_SINGLETON_STATIC_INSTANCE(LayoutEngine);
188
189bool LayoutCacheKey::operator==(const LayoutCacheKey& other) const {
190    return mId == other.mId
191            && mStart == other.mStart
192            && mCount == other.mCount
193            && mStyle == other.mStyle
194            && mSize == other.mSize
195            && mScaleX == other.mScaleX
196            && mSkewX == other.mSkewX
197            && mLetterSpacing == other.mLetterSpacing
198            && mPaintFlags == other.mPaintFlags
199            && mIsRtl == other.mIsRtl
200            && mNchars == other.mNchars
201            && !memcmp(mChars, other.mChars, mNchars * sizeof(uint16_t));
202}
203
204hash_t LayoutCacheKey::hash() const {
205    uint32_t hash = JenkinsHashMix(0, mId);
206    hash = JenkinsHashMix(hash, mStart);
207    hash = JenkinsHashMix(hash, mCount);
208    hash = JenkinsHashMix(hash, hash_type(mStyle));
209    hash = JenkinsHashMix(hash, hash_type(mSize));
210    hash = JenkinsHashMix(hash, hash_type(mScaleX));
211    hash = JenkinsHashMix(hash, hash_type(mSkewX));
212    hash = JenkinsHashMix(hash, hash_type(mLetterSpacing));
213    hash = JenkinsHashMix(hash, hash_type(mPaintFlags));
214    hash = JenkinsHashMix(hash, hash_type(mIsRtl));
215    hash = JenkinsHashMixShorts(hash, mChars, mNchars);
216    return JenkinsHashWhiten(hash);
217}
218
219hash_t hash_type(const LayoutCacheKey& key) {
220    return key.hash();
221}
222
223Bitmap::Bitmap(int width, int height) : width(width), height(height) {
224    buf = new uint8_t[width * height]();
225}
226
227Bitmap::~Bitmap() {
228    delete[] buf;
229}
230
231void Bitmap::writePnm(std::ofstream &o) const {
232    o << "P5" << std::endl;
233    o << width << " " << height << std::endl;
234    o << "255" << std::endl;
235    o.write((const char *)buf, width * height);
236    o.close();
237}
238
239void Bitmap::drawGlyph(const GlyphBitmap& bitmap, int x, int y) {
240    int bmw = bitmap.width;
241    int bmh = bitmap.height;
242    x += bitmap.left;
243    y -= bitmap.top;
244    int x0 = std::max(0, x);
245    int x1 = std::min(width, x + bmw);
246    int y0 = std::max(0, y);
247    int y1 = std::min(height, y + bmh);
248    const unsigned char* src = bitmap.buffer + (y0 - y) * bmw + (x0 - x);
249    uint8_t* dst = buf + y0 * width;
250    for (int yy = y0; yy < y1; yy++) {
251        for (int xx = x0; xx < x1; xx++) {
252            int pixel = (int)dst[xx] + (int)src[xx - x];
253            pixel = pixel > 0xff ? 0xff : pixel;
254            dst[xx] = pixel;
255        }
256        src += bmw;
257        dst += width;
258    }
259}
260
261void MinikinRect::join(const MinikinRect& r) {
262    if (isEmpty()) {
263        set(r);
264    } else if (!r.isEmpty()) {
265        mLeft = std::min(mLeft, r.mLeft);
266        mTop = std::min(mTop, r.mTop);
267        mRight = std::max(mRight, r.mRight);
268        mBottom = std::max(mBottom, r.mBottom);
269    }
270}
271
272// Deprecated. Remove when callers are removed.
273void Layout::init() {
274}
275
276void Layout::reset() {
277    mGlyphs.clear();
278    mFaces.clear();
279    mBounds.setEmpty();
280    mAdvances.clear();
281    mAdvance = 0;
282}
283
284void Layout::setFontCollection(const FontCollection* collection) {
285    mCollection = collection;
286}
287
288hb_blob_t* referenceTable(hb_face_t* face, hb_tag_t tag, void* userData)  {
289    MinikinFont* font = reinterpret_cast<MinikinFont*>(userData);
290    size_t length = 0;
291    bool ok = font->GetTable(tag, NULL, &length);
292    if (!ok) {
293        return 0;
294    }
295    char* buffer = reinterpret_cast<char*>(malloc(length));
296    if (!buffer) {
297        return 0;
298    }
299    ok = font->GetTable(tag, reinterpret_cast<uint8_t*>(buffer), &length);
300    printf("referenceTable %c%c%c%c length=%d %d\n",
301        (tag >>24) & 0xff, (tag>>16)&0xff, (tag>>8)&0xff, tag&0xff, length, ok);
302    if (!ok) {
303        free(buffer);
304        return 0;
305    }
306    return hb_blob_create(const_cast<char*>(buffer), length,
307        HB_MEMORY_MODE_WRITABLE, buffer, free);
308}
309
310static hb_bool_t harfbuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoint_t unicode, hb_codepoint_t variationSelector, hb_codepoint_t* glyph, void* userData)
311{
312    MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
313    MinikinFont* font = paint->font;
314    uint32_t glyph_id;
315    bool ok = font->GetGlyph(unicode, &glyph_id);
316    if (ok) {
317        *glyph = glyph_id;
318    }
319    return ok;
320}
321
322static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
323{
324    MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
325    MinikinFont* font = paint->font;
326    float advance = font->GetHorizontalAdvance(glyph, *paint);
327    return 256 * advance + 0.5;
328}
329
330static hb_bool_t harfbuzzGetGlyphHorizontalOrigin(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_position_t* x, hb_position_t* y, void* userData)
331{
332    // Just return true, following the way that Harfbuzz-FreeType
333    // implementation does.
334    return true;
335}
336
337hb_font_funcs_t* getHbFontFuncs() {
338    static hb_font_funcs_t* hbFontFuncs = 0;
339
340    if (hbFontFuncs == 0) {
341        hbFontFuncs = hb_font_funcs_create();
342        hb_font_funcs_set_glyph_func(hbFontFuncs, harfbuzzGetGlyph, 0, 0);
343        hb_font_funcs_set_glyph_h_advance_func(hbFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
344        hb_font_funcs_set_glyph_h_origin_func(hbFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
345        hb_font_funcs_make_immutable(hbFontFuncs);
346    }
347    return hbFontFuncs;
348}
349
350static hb_face_t* getHbFace(MinikinFont* minikinFont) {
351    HbFaceCache& cache = LayoutEngine::getInstance().hbFaceCache;
352    int32_t fontId = minikinFont->GetUniqueId();
353    hb_face_t* face = cache.mCache.get(fontId);
354    if (face == NULL) {
355        face = hb_face_create_for_tables(referenceTable, minikinFont, NULL);
356        cache.mCache.put(fontId, face);
357    }
358    return face;
359}
360
361static hb_font_t* create_hb_font(MinikinFont* minikinFont, MinikinPaint* minikinPaint) {
362    hb_face_t* face = getHbFace(minikinFont);
363    hb_font_t* font = hb_font_create(face);
364    hb_font_set_funcs(font, getHbFontFuncs(), minikinPaint, 0);
365    return font;
366}
367
368static float HBFixedToFloat(hb_position_t v)
369{
370    return scalbnf (v, -8);
371}
372
373static hb_position_t HBFloatToFixed(float v)
374{
375    return scalbnf (v, +8);
376}
377
378void Layout::dump() const {
379    for (size_t i = 0; i < mGlyphs.size(); i++) {
380        const LayoutGlyph& glyph = mGlyphs[i];
381        std::cout << glyph.glyph_id << ": " << glyph.x << ", " << glyph.y << std::endl;
382    }
383}
384
385int Layout::findFace(FakedFont face, LayoutContext* ctx) {
386    unsigned int ix;
387    for (ix = 0; ix < mFaces.size(); ix++) {
388        if (mFaces[ix].font == face.font) {
389            return ix;
390        }
391    }
392    mFaces.push_back(face);
393    // Note: ctx == NULL means we're copying from the cache, no need to create
394    // corresponding hb_font object.
395    if (ctx != NULL) {
396        hb_font_t* font = create_hb_font(face.font, &ctx->paint);
397        ctx->hbFonts.push_back(font);
398    }
399    return ix;
400}
401
402static hb_script_t codePointToScript(hb_codepoint_t codepoint) {
403    static hb_unicode_funcs_t* u = 0;
404    if (!u) {
405        u = hb_icu_get_unicode_funcs();
406    }
407    return hb_unicode_script(u, codepoint);
408}
409
410static hb_codepoint_t decodeUtf16(const uint16_t* chars, size_t len, ssize_t* iter) {
411    const uint16_t v = chars[(*iter)++];
412    // test whether v in (0xd800..0xdfff), lead or trail surrogate
413    if ((v & 0xf800) == 0xd800) {
414        // test whether v in (0xd800..0xdbff), lead surrogate
415        if (size_t(*iter) < len && (v & 0xfc00) == 0xd800) {
416            const uint16_t v2 = chars[(*iter)++];
417            // test whether v2 in (0xdc00..0xdfff), trail surrogate
418            if ((v2 & 0xfc00) == 0xdc00) {
419                // (0xd800 0xdc00) in utf-16 maps to 0x10000 in ucs-32
420                const hb_codepoint_t delta = (0xd800 << 10) + 0xdc00 - 0x10000;
421                return (((hb_codepoint_t)v) << 10) + v2 - delta;
422            }
423            (*iter) -= 1;
424            return 0xFFFDu;
425        } else {
426            return 0xFFFDu;
427        }
428    } else {
429        return v;
430    }
431}
432
433static hb_script_t getScriptRun(const uint16_t* chars, size_t len, ssize_t* iter) {
434    if (size_t(*iter) == len) {
435        return HB_SCRIPT_UNKNOWN;
436    }
437    uint32_t cp = decodeUtf16(chars, len, iter);
438    hb_script_t current_script = codePointToScript(cp);
439    for (;;) {
440        if (size_t(*iter) == len)
441            break;
442        const ssize_t prev_iter = *iter;
443        cp = decodeUtf16(chars, len, iter);
444        const hb_script_t script = codePointToScript(cp);
445        if (script != current_script) {
446            if (current_script == HB_SCRIPT_INHERITED ||
447                current_script == HB_SCRIPT_COMMON) {
448                current_script = script;
449            } else if (script == HB_SCRIPT_INHERITED ||
450                script == HB_SCRIPT_COMMON) {
451                continue;
452            } else {
453                *iter = prev_iter;
454                break;
455            }
456        }
457    }
458    if (current_script == HB_SCRIPT_INHERITED) {
459        current_script = HB_SCRIPT_COMMON;
460    }
461
462    return current_script;
463}
464
465/**
466 * For the purpose of layout, a word break is a boundary with no
467 * kerning or complex script processing. This is necessarily a
468 * heuristic, but should be accurate most of the time.
469 */
470static bool isWordBreak(int c) {
471    if (c == ' ' || (c >= 0x2000 && c <= 0x200a) || c == 0x3000) {
472        // spaces
473        return true;
474    }
475    if ((c >= 0x3400 && c <= 0x9fff)) {
476        // CJK ideographs (and yijing hexagram symbols)
477        return true;
478    }
479    // Note: kana is not included, as sophisticated fonts may kern kana
480    return false;
481}
482
483/**
484 * Return offset of previous word break. It is either < offset or == 0.
485 */
486static size_t getPrevWordBreak(const uint16_t* chars, size_t offset) {
487    if (offset == 0) return 0;
488    if (isWordBreak(chars[offset - 1])) {
489        return offset - 1;
490    }
491    for (size_t i = offset - 1; i > 0; i--) {
492        if (isWordBreak(chars[i - 1])) {
493            return i;
494        }
495    }
496    return 0;
497}
498
499/**
500 * Return offset of next word break. It is either > offset or == len.
501 */
502static size_t getNextWordBreak(const uint16_t* chars, size_t offset, size_t len) {
503    if (offset >= len) return len;
504    if (isWordBreak(chars[offset])) {
505        return offset + 1;
506    }
507    for (size_t i = offset + 1; i < len; i++) {
508        if (isWordBreak(chars[i])) {
509            return i;
510        }
511    }
512    return len;
513}
514
515void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
516        int bidiFlags, const FontStyle &style, const MinikinPaint &paint) {
517    AutoMutex _l(gMinikinLock);
518
519    LayoutContext ctx;
520    ctx.style = style;
521    ctx.paint = paint;
522
523    bool isRtl = (bidiFlags & kDirection_Mask) != 0;
524    bool doSingleRun = true;
525
526    reset();
527    mAdvances.resize(count, 0);
528
529    if (!(bidiFlags == kBidi_Force_LTR || bidiFlags == kBidi_Force_RTL)) {
530        UBiDi* bidi = ubidi_open();
531        if (bidi) {
532            UErrorCode status = U_ZERO_ERROR;
533            UBiDiLevel bidiReq = bidiFlags;
534            if (bidiFlags == kBidi_Default_LTR) {
535                bidiReq = UBIDI_DEFAULT_LTR;
536            } else if (bidiFlags == kBidi_Default_RTL) {
537                bidiReq = UBIDI_DEFAULT_RTL;
538            }
539            ubidi_setPara(bidi, buf, bufSize, bidiReq, NULL, &status);
540            if (U_SUCCESS(status)) {
541                int paraDir = ubidi_getParaLevel(bidi) & kDirection_Mask;
542                ssize_t rc = ubidi_countRuns(bidi, &status);
543                if (!U_SUCCESS(status) || rc < 0) {
544                    ALOGW("error counting bidi runs, status = %d", status);
545                }
546                if (!U_SUCCESS(status) || rc <= 1) {
547                    isRtl = (paraDir == kBidi_RTL);
548                } else {
549                    doSingleRun = false;
550                    // iterate through runs
551                    for (ssize_t i = 0; i < (ssize_t)rc; i++) {
552                        int32_t startRun = -1;
553                        int32_t lengthRun = -1;
554                        UBiDiDirection runDir = ubidi_getVisualRun(bidi, i, &startRun, &lengthRun);
555                        if (startRun == -1 || lengthRun == -1) {
556                            ALOGE("invalid visual run");
557                            // skip the invalid run
558                            continue;
559                        }
560                        int32_t endRun = std::min(startRun + lengthRun, int32_t(start + count));
561                        startRun = std::max(startRun, int32_t(start));
562                        lengthRun = endRun - startRun;
563                        if (lengthRun > 0) {
564                            isRtl = (runDir == UBIDI_RTL);
565                            doLayoutRunCached(buf, startRun, lengthRun, bufSize, isRtl, &ctx,
566                                start);
567                        }
568                    }
569                }
570            } else {
571                ALOGE("error calling ubidi_setPara, status = %d", status);
572            }
573            ubidi_close(bidi);
574        } else {
575            ALOGE("error creating bidi object");
576        }
577    }
578    if (doSingleRun) {
579        doLayoutRunCached(buf, start, count, bufSize, isRtl, &ctx, start);
580    }
581    ctx.clearHbFonts();
582}
583
584void Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
585        bool isRtl, LayoutContext* ctx, size_t dstStart) {
586    if (!isRtl) {
587        // left to right
588        size_t wordstart = start == bufSize ? start : getPrevWordBreak(buf, start + 1);
589        size_t wordend;
590        for (size_t iter = start; iter < start + count; iter = wordend) {
591            wordend = getNextWordBreak(buf, iter, bufSize);
592            size_t wordcount = std::min(start + count, wordend) - iter;
593            doLayoutWord(buf + wordstart, iter - wordstart, wordcount, wordend - wordstart,
594                    isRtl, ctx, iter - dstStart);
595            wordstart = wordend;
596        }
597    } else {
598        // right to left
599        size_t wordstart;
600        size_t end = start + count;
601        size_t wordend = end == 0 ? 0 : getNextWordBreak(buf, end - 1, bufSize);
602        for (size_t iter = end; iter > start; iter = wordstart) {
603            wordstart = getPrevWordBreak(buf, iter);
604            size_t bufStart = std::max(start, wordstart);
605            doLayoutWord(buf + wordstart, bufStart - wordstart, iter - bufStart,
606                    wordend - wordstart, isRtl, ctx, bufStart - dstStart);
607            wordend = wordstart;
608        }
609    }
610}
611
612void Layout::doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
613        bool isRtl, LayoutContext* ctx, size_t bufStart) {
614    LayoutCache& cache = LayoutEngine::getInstance().layoutCache;
615    LayoutCacheKey key(mCollection, ctx->paint, ctx->style, buf, start, count, bufSize, isRtl);
616    bool skipCache = ctx->paint.skipCache();
617    if (skipCache) {
618        Layout layout;
619        key.doLayout(&layout, ctx, mCollection);
620        appendLayout(&layout, bufStart);
621    } else {
622        Layout* layout = cache.get(key, ctx, mCollection);
623        appendLayout(layout, bufStart);
624    }
625}
626
627static void addFeatures(const string &str, vector<hb_feature_t>* features) {
628    if (!str.size())
629        return;
630
631    const char* start = str.c_str();
632    const char* end = start + str.size();
633
634    while (start < end) {
635        static hb_feature_t feature;
636        const char* p = strchr(start, ',');
637        if (!p)
638            p = end;
639        /* We do not allow setting features on ranges.  As such, reject any
640         * setting that has non-universal range. */
641        if (hb_feature_from_string (start, p - start, &feature)
642                && feature.start == 0 && feature.end == (unsigned int) -1)
643            features->push_back(feature);
644        start = p + 1;
645    }
646}
647
648void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
649        bool isRtl, LayoutContext* ctx) {
650    hb_buffer_t* buffer = LayoutEngine::getInstance().hbBuffer;
651    vector<FontCollection::Run> items;
652    mCollection->itemize(buf + start, count, ctx->style, &items);
653    if (isRtl) {
654        std::reverse(items.begin(), items.end());
655    }
656
657    vector<hb_feature_t> features;
658    // Disable default-on non-required ligature features if letter-spacing
659    // See http://dev.w3.org/csswg/css-text-3/#letter-spacing-property
660    // "When the effective spacing between two characters is not zero (due to
661    // either justification or a non-zero value of letter-spacing), user agents
662    // should not apply optional ligatures."
663    if (fabs(ctx->paint.letterSpacing) > 0.03)
664    {
665        static const hb_feature_t no_liga = { HB_TAG('l', 'i', 'g', 'a'), 0, 0, ~0u };
666        static const hb_feature_t no_clig = { HB_TAG('c', 'l', 'i', 'g'), 0, 0, ~0u };
667        features.push_back(no_liga);
668        features.push_back(no_clig);
669    }
670    addFeatures(ctx->paint.fontFeatureSettings, &features);
671
672    double size = ctx->paint.size;
673    double scaleX = ctx->paint.scaleX;
674    double letterSpace = ctx->paint.letterSpacing * size * scaleX;
675    double letterSpaceHalfLeft;
676    if ((ctx->paint.paintFlags & LinearTextFlag) == 0) {
677        letterSpace = round(letterSpace);
678        letterSpaceHalfLeft = floor(letterSpace * 0.5);
679    } else {
680        letterSpaceHalfLeft = letterSpace * 0.5;
681    }
682    double letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
683
684    float x = mAdvance;
685    float y = 0;
686    for (size_t run_ix = 0; run_ix < items.size(); run_ix++) {
687        FontCollection::Run &run = items[run_ix];
688        if (run.fakedFont.font == NULL) {
689            ALOGE("no font for run starting u+%04x length %d", buf[run.start], run.end - run.start);
690            continue;
691        }
692        int font_ix = findFace(run.fakedFont, ctx);
693        ctx->paint.font = mFaces[font_ix].font;
694        ctx->paint.fakery = mFaces[font_ix].fakery;
695        hb_font_t* hbFont = ctx->hbFonts[font_ix];
696#ifdef VERBOSE
697        std::cout << "Run " << run_ix << ", font " << font_ix <<
698            " [" << run.start << ":" << run.end << "]" << std::endl;
699#endif
700
701        hb_font_set_ppem(hbFont, size * scaleX, size);
702        hb_font_set_scale(hbFont, HBFloatToFixed(size * scaleX), HBFloatToFixed(size));
703
704        // TODO: if there are multiple scripts within a font in an RTL run,
705        // we need to reorder those runs. This is unlikely with our current
706        // font stack, but should be done for correctness.
707        ssize_t srunend;
708        for (ssize_t srunstart = run.start; srunstart < run.end; srunstart = srunend) {
709            srunend = srunstart;
710            hb_script_t script = getScriptRun(buf + start, run.end, &srunend);
711
712            hb_buffer_reset(buffer);
713            hb_buffer_set_script(buffer, script);
714            hb_buffer_set_direction(buffer, isRtl? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
715            FontLanguage language = ctx->style.getLanguage();
716            if (language) {
717                string lang = language.getString();
718                hb_buffer_set_language(buffer, hb_language_from_string(lang.c_str(), -1));
719            }
720            hb_buffer_add_utf16(buffer, buf, bufSize, srunstart + start, srunend - srunstart);
721            hb_shape(hbFont, buffer, features.empty() ? NULL : &features[0], features.size());
722            unsigned int numGlyphs;
723            hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, &numGlyphs);
724            hb_glyph_position_t* positions = hb_buffer_get_glyph_positions(buffer, NULL);
725            if (numGlyphs)
726            {
727                mAdvances[info[0].cluster - start] += letterSpaceHalfLeft;
728                x += letterSpaceHalfLeft;
729            }
730            for (unsigned int i = 0; i < numGlyphs; i++) {
731    #ifdef VERBOSE
732                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 <<
733                ": " << HBFixedToFloat(positions[i].x_advance) << "; " << positions[i].x_offset << ", " << positions[i].y_offset << std::endl;
734    #endif
735                if (i > 0 && info[i - 1].cluster != info[i].cluster) {
736                    mAdvances[info[i - 1].cluster - start] += letterSpaceHalfRight;
737                    mAdvances[info[i].cluster - start] += letterSpaceHalfLeft;
738                    x += letterSpace;
739                }
740
741                hb_codepoint_t glyph_ix = info[i].codepoint;
742                float xoff = HBFixedToFloat(positions[i].x_offset);
743                float yoff = -HBFixedToFloat(positions[i].y_offset);
744                xoff += yoff * ctx->paint.skewX;
745                LayoutGlyph glyph = {font_ix, glyph_ix, x + xoff, y + yoff};
746                mGlyphs.push_back(glyph);
747                float xAdvance = HBFixedToFloat(positions[i].x_advance);
748                if ((ctx->paint.paintFlags & LinearTextFlag) == 0) {
749                    xAdvance = roundf(xAdvance);
750                }
751                MinikinRect glyphBounds;
752                ctx->paint.font->GetBounds(&glyphBounds, glyph_ix, ctx->paint);
753                glyphBounds.offset(x + xoff, y + yoff);
754                mBounds.join(glyphBounds);
755                mAdvances[info[i].cluster - start] += xAdvance;
756                x += xAdvance;
757            }
758            if (numGlyphs)
759            {
760                mAdvances[info[numGlyphs - 1].cluster - start] += letterSpaceHalfRight;
761                x += letterSpaceHalfRight;
762            }
763        }
764    }
765    mAdvance = x;
766}
767
768void Layout::appendLayout(Layout* src, size_t start) {
769    int fontMapStack[16];
770    int* fontMap;
771    if (src->mFaces.size() < sizeof(fontMapStack) / sizeof(fontMapStack[0])) {
772        fontMap = fontMapStack;
773    } else {
774        fontMap = new int[src->mFaces.size()];
775    }
776    for (size_t i = 0; i < src->mFaces.size(); i++) {
777        int font_ix = findFace(src->mFaces[i], NULL);
778        fontMap[i] = font_ix;
779    }
780    int x0 = mAdvance;
781    for (size_t i = 0; i < src->mGlyphs.size(); i++) {
782        LayoutGlyph& srcGlyph = src->mGlyphs[i];
783        int font_ix = fontMap[srcGlyph.font_ix];
784        unsigned int glyph_id = srcGlyph.glyph_id;
785        float x = x0 + srcGlyph.x;
786        float y = srcGlyph.y;
787        LayoutGlyph glyph = {font_ix, glyph_id, x, y};
788        mGlyphs.push_back(glyph);
789    }
790    for (size_t i = 0; i < src->mAdvances.size(); i++) {
791        mAdvances[i + start] = src->mAdvances[i];
792    }
793    MinikinRect srcBounds(src->mBounds);
794    srcBounds.offset(x0, 0);
795    mBounds.join(srcBounds);
796    mAdvance += src->mAdvance;
797
798    if (fontMap != fontMapStack) {
799        delete[] fontMap;
800    }
801}
802
803void Layout::draw(Bitmap* surface, int x0, int y0, float size) const {
804    /*
805    TODO: redo as MinikinPaint settings
806    if (mProps.hasTag(minikinHinting)) {
807        int hintflags = mProps.value(minikinHinting).getIntValue();
808        if (hintflags & 1) load_flags |= FT_LOAD_NO_HINTING;
809        if (hintflags & 2) load_flags |= FT_LOAD_NO_AUTOHINT;
810    }
811    */
812    for (size_t i = 0; i < mGlyphs.size(); i++) {
813        const LayoutGlyph& glyph = mGlyphs[i];
814        MinikinFont* mf = mFaces[glyph.font_ix].font;
815        MinikinFontFreeType* face = static_cast<MinikinFontFreeType*>(mf);
816        GlyphBitmap glyphBitmap;
817        MinikinPaint paint;
818        paint.size = size;
819        bool ok = face->Render(glyph.glyph_id, paint, &glyphBitmap);
820        printf("glyphBitmap.width=%d, glyphBitmap.height=%d (%d, %d) x=%f, y=%f, ok=%d\n",
821            glyphBitmap.width, glyphBitmap.height, glyphBitmap.left, glyphBitmap.top, glyph.x, glyph.y, ok);
822        if (ok) {
823            surface->drawGlyph(glyphBitmap,
824                x0 + int(floor(glyph.x + 0.5)), y0 + int(floor(glyph.y + 0.5)));
825        }
826    }
827}
828
829size_t Layout::nGlyphs() const {
830    return mGlyphs.size();
831}
832
833MinikinFont* Layout::getFont(int i) const {
834    const LayoutGlyph& glyph = mGlyphs[i];
835    return mFaces[glyph.font_ix].font;
836}
837
838FontFakery Layout::getFakery(int i) const {
839    const LayoutGlyph& glyph = mGlyphs[i];
840    return mFaces[glyph.font_ix].fakery;
841}
842
843unsigned int Layout::getGlyphId(int i) const {
844    const LayoutGlyph& glyph = mGlyphs[i];
845    return glyph.glyph_id;
846}
847
848float Layout::getX(int i) const {
849    const LayoutGlyph& glyph = mGlyphs[i];
850    return glyph.x;
851}
852
853float Layout::getY(int i) const {
854    const LayoutGlyph& glyph = mGlyphs[i];
855    return glyph.y;
856}
857
858float Layout::getAdvance() const {
859    return mAdvance;
860}
861
862void Layout::getAdvances(float* advances) {
863    memcpy(advances, &mAdvances[0], mAdvances.size() * sizeof(float));
864}
865
866void Layout::getBounds(MinikinRect* bounds) {
867    bounds->set(mBounds);
868}
869
870void Layout::purgeCaches() {
871    AutoMutex _l(gMinikinLock);
872    LayoutCache& layoutCache = LayoutEngine::getInstance().layoutCache;
873    layoutCache.clear();
874    HbFaceCache& hbCache = LayoutEngine::getInstance().hbFaceCache;
875    hbCache.mCache.clear();
876}
877
878}  // namespace android
879