Layout.cpp revision 6c4d167bff33c24c239d77ddb1044b18d180766a 
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 minikin {
45
46Bitmap::Bitmap(int width, int height) : width(width), height(height) {
47    buf = new uint8_t[width * height]();
48}
49
50Bitmap::~Bitmap() {
51    delete[] buf;
52}
53
54void Bitmap::writePnm(std::ofstream &o) const {
55    o << "P5" << std::endl;
56    o << width << " " << height << std::endl;
57    o << "255" << std::endl;
58    o.write((const char *)buf, width * height);
59    o.close();
60}
61
62void Bitmap::drawGlyph(const android::GlyphBitmap& bitmap, int x, int y) {
63    int bmw = bitmap.width;
64    int bmh = bitmap.height;
65    x += bitmap.left;
66    y -= bitmap.top;
67    int x0 = std::max(0, x);
68    int x1 = std::min(width, x + bmw);
69    int y0 = std::max(0, y);
70    int y1 = std::min(height, y + bmh);
71    const unsigned char* src = bitmap.buffer + (y0 - y) * bmw + (x0 - x);
72    uint8_t* dst = buf + y0 * width;
73    for (int yy = y0; yy < y1; yy++) {
74        for (int xx = x0; xx < x1; xx++) {
75            int pixel = (int)dst[xx] + (int)src[xx - x];
76            pixel = pixel > 0xff ? 0xff : pixel;
77            dst[xx] = pixel;
78        }
79        src += bmw;
80        dst += width;
81    }
82}
83
84} // namespace minikin
85
86namespace android {
87
88const int kDirection_Mask = 0x1;
89
90struct LayoutContext {
91    MinikinPaint paint;
92    FontStyle style;
93    std::vector<hb_font_t*> hbFonts;  // parallel to mFaces
94
95    void clearHbFonts() {
96        for (size_t i = 0; i < hbFonts.size(); i++) {
97            hb_font_destroy(hbFonts[i]);
98        }
99        hbFonts.clear();
100    }
101};
102
103// Layout cache datatypes
104
105class LayoutCacheKey {
106public:
107    LayoutCacheKey(const FontCollection* collection, const MinikinPaint& paint, FontStyle style,
108            const uint16_t* chars, size_t start, size_t count, size_t nchars, bool dir)
109            : mChars(chars), mNchars(nchars),
110            mStart(start), mCount(count), mId(collection->getId()), mStyle(style),
111            mSize(paint.size), mScaleX(paint.scaleX), mSkewX(paint.skewX),
112            mLetterSpacing(paint.letterSpacing),
113            mPaintFlags(paint.paintFlags), mHyphenEdit(paint.hyphenEdit), mIsRtl(dir) {
114    }
115    bool operator==(const LayoutCacheKey &other) const;
116    hash_t hash() const;
117
118    void copyText() {
119        uint16_t* charsCopy = new uint16_t[mNchars];
120        memcpy(charsCopy, mChars, mNchars * sizeof(uint16_t));
121        mChars = charsCopy;
122    }
123    void freeText() {
124        delete[] mChars;
125        mChars = NULL;
126    }
127
128    void doLayout(Layout* layout, LayoutContext* ctx, const FontCollection* collection) const {
129        layout->setFontCollection(collection);
130        layout->mAdvances.resize(mCount, 0);
131        ctx->clearHbFonts();
132        layout->doLayoutRun(mChars, mStart, mCount, mNchars, mIsRtl, ctx);
133    }
134
135private:
136    const uint16_t* mChars;
137    size_t mNchars;
138    size_t mStart;
139    size_t mCount;
140    uint32_t mId;  // for the font collection
141    FontStyle mStyle;
142    float mSize;
143    float mScaleX;
144    float mSkewX;
145    float mLetterSpacing;
146    int32_t mPaintFlags;
147    HyphenEdit mHyphenEdit;
148    bool mIsRtl;
149    // Note: any fields added to MinikinPaint must also be reflected here.
150    // TODO: language matching (possibly integrate into style)
151};
152
153class LayoutCache : private OnEntryRemoved<LayoutCacheKey, Layout*> {
154public:
155    LayoutCache() : mCache(kMaxEntries) {
156        mCache.setOnEntryRemovedListener(this);
157    }
158
159    void clear() {
160        mCache.clear();
161    }
162
163    Layout* get(LayoutCacheKey& key, LayoutContext* ctx, const FontCollection* collection) {
164        Layout* layout = mCache.get(key);
165        if (layout == NULL) {
166            key.copyText();
167            layout = new Layout();
168            key.doLayout(layout, ctx, collection);
169            mCache.put(key, layout);
170        }
171        return layout;
172    }
173
174private:
175    // callback for OnEntryRemoved
176    void operator()(LayoutCacheKey& key, Layout*& value) {
177        key.freeText();
178        delete value;
179    }
180
181    LruCache<LayoutCacheKey, Layout*> mCache;
182
183    //static const size_t kMaxEntries = LruCache<LayoutCacheKey, Layout*>::kUnlimitedCapacity;
184
185    // TODO: eviction based on memory footprint; for now, we just use a constant
186    // number of strings
187    static const size_t kMaxEntries = 5000;
188};
189
190class HbFaceCache : private OnEntryRemoved<int32_t, hb_face_t*> {
191public:
192    HbFaceCache() : mCache(kMaxEntries) {
193        mCache.setOnEntryRemovedListener(this);
194    }
195
196    // callback for OnEntryRemoved
197    void operator()(int32_t& key, hb_face_t*& value) {
198        hb_face_destroy(value);
199    }
200
201    LruCache<int32_t, hb_face_t*> mCache;
202private:
203    static const size_t kMaxEntries = 100;
204};
205
206static unsigned int disabledDecomposeCompatibility(hb_unicode_funcs_t*, hb_codepoint_t,
207                                                   hb_codepoint_t*, void*) {
208    return 0;
209}
210
211class LayoutEngine : public Singleton<LayoutEngine> {
212public:
213    LayoutEngine() {
214        unicodeFunctions = hb_unicode_funcs_create(hb_icu_get_unicode_funcs());
215        /* Disable the function used for compatibility decomposition */
216        hb_unicode_funcs_set_decompose_compatibility_func(
217                unicodeFunctions, disabledDecomposeCompatibility, NULL, NULL);
218        hbBuffer = hb_buffer_create();
219        hb_buffer_set_unicode_funcs(hbBuffer, unicodeFunctions);
220    }
221
222    hb_buffer_t* hbBuffer;
223    hb_unicode_funcs_t* unicodeFunctions;
224    LayoutCache layoutCache;
225    HbFaceCache hbFaceCache;
226};
227
228ANDROID_SINGLETON_STATIC_INSTANCE(LayoutEngine);
229
230bool LayoutCacheKey::operator==(const LayoutCacheKey& other) const {
231    return mId == other.mId
232            && mStart == other.mStart
233            && mCount == other.mCount
234            && mStyle == other.mStyle
235            && mSize == other.mSize
236            && mScaleX == other.mScaleX
237            && mSkewX == other.mSkewX
238            && mLetterSpacing == other.mLetterSpacing
239            && mPaintFlags == other.mPaintFlags
240            && mHyphenEdit == other.mHyphenEdit
241            && mIsRtl == other.mIsRtl
242            && mNchars == other.mNchars
243            && !memcmp(mChars, other.mChars, mNchars * sizeof(uint16_t));
244}
245
246hash_t LayoutCacheKey::hash() const {
247    uint32_t hash = JenkinsHashMix(0, mId);
248    hash = JenkinsHashMix(hash, mStart);
249    hash = JenkinsHashMix(hash, mCount);
250    hash = JenkinsHashMix(hash, hash_type(mStyle));
251    hash = JenkinsHashMix(hash, hash_type(mSize));
252    hash = JenkinsHashMix(hash, hash_type(mScaleX));
253    hash = JenkinsHashMix(hash, hash_type(mSkewX));
254    hash = JenkinsHashMix(hash, hash_type(mLetterSpacing));
255    hash = JenkinsHashMix(hash, hash_type(mPaintFlags));
256    hash = JenkinsHashMix(hash, hash_type(mHyphenEdit.hasHyphen()));
257    hash = JenkinsHashMix(hash, hash_type(mIsRtl));
258    hash = JenkinsHashMixShorts(hash, mChars, mNchars);
259    return JenkinsHashWhiten(hash);
260}
261
262hash_t hash_type(const LayoutCacheKey& key) {
263    return key.hash();
264}
265
266void MinikinRect::join(const MinikinRect& r) {
267    if (isEmpty()) {
268        set(r);
269    } else if (!r.isEmpty()) {
270        mLeft = std::min(mLeft, r.mLeft);
271        mTop = std::min(mTop, r.mTop);
272        mRight = std::max(mRight, r.mRight);
273        mBottom = std::max(mBottom, r.mBottom);
274    }
275}
276
277// Deprecated. Remove when callers are removed.
278void Layout::init() {
279}
280
281void Layout::reset() {
282    mGlyphs.clear();
283    mFaces.clear();
284    mBounds.setEmpty();
285    mAdvances.clear();
286    mAdvance = 0;
287}
288
289void Layout::setFontCollection(const FontCollection* collection) {
290    mCollection = collection;
291}
292
293hb_blob_t* referenceTable(hb_face_t* face, hb_tag_t tag, void* userData)  {
294    MinikinFont* font = reinterpret_cast<MinikinFont*>(userData);
295    size_t length = 0;
296    bool ok = font->GetTable(tag, NULL, &length);
297    if (!ok) {
298        return 0;
299    }
300    char* buffer = reinterpret_cast<char*>(malloc(length));
301    if (!buffer) {
302        return 0;
303    }
304    ok = font->GetTable(tag, reinterpret_cast<uint8_t*>(buffer), &length);
305    printf("referenceTable %c%c%c%c length=%d %d\n",
306        (tag >>24) & 0xff, (tag>>16)&0xff, (tag>>8)&0xff, tag&0xff, length, ok);
307    if (!ok) {
308        free(buffer);
309        return 0;
310    }
311    return hb_blob_create(const_cast<char*>(buffer), length,
312        HB_MEMORY_MODE_WRITABLE, buffer, free);
313}
314
315static hb_bool_t harfbuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoint_t unicode, hb_codepoint_t variationSelector, hb_codepoint_t* glyph, void* userData)
316{
317    MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
318    MinikinFont* font = paint->font;
319    uint32_t glyph_id;
320    bool ok = font->GetGlyph(unicode, &glyph_id);
321    if (ok) {
322        *glyph = glyph_id;
323    }
324    return ok;
325}
326
327static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
328{
329    MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
330    MinikinFont* font = paint->font;
331    float advance = font->GetHorizontalAdvance(glyph, *paint);
332    return 256 * advance + 0.5;
333}
334
335static hb_bool_t harfbuzzGetGlyphHorizontalOrigin(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_position_t* x, hb_position_t* y, void* userData)
336{
337    // Just return true, following the way that Harfbuzz-FreeType
338    // implementation does.
339    return true;
340}
341
342hb_font_funcs_t* getHbFontFuncs() {
343    static hb_font_funcs_t* hbFontFuncs = 0;
344
345    if (hbFontFuncs == 0) {
346        hbFontFuncs = hb_font_funcs_create();
347        hb_font_funcs_set_glyph_func(hbFontFuncs, harfbuzzGetGlyph, 0, 0);
348        hb_font_funcs_set_glyph_h_advance_func(hbFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
349        hb_font_funcs_set_glyph_h_origin_func(hbFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
350        hb_font_funcs_make_immutable(hbFontFuncs);
351    }
352    return hbFontFuncs;
353}
354
355static hb_face_t* getHbFace(MinikinFont* minikinFont) {
356    HbFaceCache& cache = LayoutEngine::getInstance().hbFaceCache;
357    int32_t fontId = minikinFont->GetUniqueId();
358    hb_face_t* face = cache.mCache.get(fontId);
359    if (face == NULL) {
360        face = hb_face_create_for_tables(referenceTable, minikinFont, NULL);
361        cache.mCache.put(fontId, face);
362    }
363    return face;
364}
365
366static hb_font_t* create_hb_font(MinikinFont* minikinFont, MinikinPaint* minikinPaint) {
367    hb_face_t* face = getHbFace(minikinFont);
368    hb_font_t* font = hb_font_create(face);
369    hb_font_set_funcs(font, getHbFontFuncs(), minikinPaint, 0);
370    return font;
371}
372
373static float HBFixedToFloat(hb_position_t v)
374{
375    return scalbnf (v, -8);
376}
377
378static hb_position_t HBFloatToFixed(float v)
379{
380    return scalbnf (v, +8);
381}
382
383void Layout::dump() const {
384    for (size_t i = 0; i < mGlyphs.size(); i++) {
385        const LayoutGlyph& glyph = mGlyphs[i];
386        std::cout << glyph.glyph_id << ": " << glyph.x << ", " << glyph.y << std::endl;
387    }
388}
389
390int Layout::findFace(FakedFont face, LayoutContext* ctx) {
391    unsigned int ix;
392    for (ix = 0; ix < mFaces.size(); ix++) {
393        if (mFaces[ix].font == face.font) {
394            return ix;
395        }
396    }
397    mFaces.push_back(face);
398    // Note: ctx == NULL means we're copying from the cache, no need to create
399    // corresponding hb_font object.
400    if (ctx != NULL) {
401        hb_font_t* font = create_hb_font(face.font, &ctx->paint);
402        ctx->hbFonts.push_back(font);
403    }
404    return ix;
405}
406
407static hb_script_t codePointToScript(hb_codepoint_t codepoint) {
408    static hb_unicode_funcs_t* u = 0;
409    if (!u) {
410        u = LayoutEngine::getInstance().unicodeFunctions;
411    }
412    return hb_unicode_script(u, codepoint);
413}
414
415static hb_codepoint_t decodeUtf16(const uint16_t* chars, size_t len, ssize_t* iter) {
416    const uint16_t v = chars[(*iter)++];
417    // test whether v in (0xd800..0xdfff), lead or trail surrogate
418    if ((v & 0xf800) == 0xd800) {
419        // test whether v in (0xd800..0xdbff), lead surrogate
420        if (size_t(*iter) < len && (v & 0xfc00) == 0xd800) {
421            const uint16_t v2 = chars[(*iter)++];
422            // test whether v2 in (0xdc00..0xdfff), trail surrogate
423            if ((v2 & 0xfc00) == 0xdc00) {
424                // (0xd800 0xdc00) in utf-16 maps to 0x10000 in ucs-32
425                const hb_codepoint_t delta = (0xd800 << 10) + 0xdc00 - 0x10000;
426                return (((hb_codepoint_t)v) << 10) + v2 - delta;
427            }
428            (*iter) -= 1;
429            return 0xFFFDu;
430        } else {
431            return 0xFFFDu;
432        }
433    } else {
434        return v;
435    }
436}
437
438static hb_script_t getScriptRun(const uint16_t* chars, size_t len, ssize_t* iter) {
439    if (size_t(*iter) == len) {
440        return HB_SCRIPT_UNKNOWN;
441    }
442    uint32_t cp = decodeUtf16(chars, len, iter);
443    hb_script_t current_script = codePointToScript(cp);
444    for (;;) {
445        if (size_t(*iter) == len)
446            break;
447        const ssize_t prev_iter = *iter;
448        cp = decodeUtf16(chars, len, iter);
449        const hb_script_t script = codePointToScript(cp);
450        if (script != current_script) {
451            if (current_script == HB_SCRIPT_INHERITED ||
452                current_script == HB_SCRIPT_COMMON) {
453                current_script = script;
454            } else if (script == HB_SCRIPT_INHERITED ||
455                script == HB_SCRIPT_COMMON) {
456                continue;
457            } else {
458                *iter = prev_iter;
459                break;
460            }
461        }
462    }
463    if (current_script == HB_SCRIPT_INHERITED) {
464        current_script = HB_SCRIPT_COMMON;
465    }
466
467    return current_script;
468}
469
470/**
471 * For the purpose of layout, a word break is a boundary with no
472 * kerning or complex script processing. This is necessarily a
473 * heuristic, but should be accurate most of the time.
474 */
475static bool isWordBreak(int c) {
476    if (c == ' ' || (c >= 0x2000 && c <= 0x200a) || c == 0x3000) {
477        // spaces
478        return true;
479    }
480    if ((c >= 0x3400 && c <= 0x9fff)) {
481        // CJK ideographs (and yijing hexagram symbols)
482        return true;
483    }
484    // Note: kana is not included, as sophisticated fonts may kern kana
485    return false;
486}
487
488/**
489 * Return offset of previous word break. It is either < offset or == 0.
490 */
491static size_t getPrevWordBreak(const uint16_t* chars, size_t offset) {
492    if (offset == 0) return 0;
493    if (isWordBreak(chars[offset - 1])) {
494        return offset - 1;
495    }
496    for (size_t i = offset - 1; i > 0; i--) {
497        if (isWordBreak(chars[i - 1])) {
498            return i;
499        }
500    }
501    return 0;
502}
503
504/**
505 * Return offset of next word break. It is either > offset or == len.
506 */
507static size_t getNextWordBreak(const uint16_t* chars, size_t offset, size_t len) {
508    if (offset >= len) return len;
509    if (isWordBreak(chars[offset])) {
510        return offset + 1;
511    }
512    for (size_t i = offset + 1; i < len; i++) {
513        if (isWordBreak(chars[i])) {
514            return i;
515        }
516    }
517    return len;
518}
519
520/**
521 * Disable certain scripts (mostly those with cursive connection) from having letterspacing
522 * applied. See https://github.com/behdad/harfbuzz/issues/64 for more details.
523 */
524static bool isScriptOkForLetterspacing(hb_script_t script) {
525    return !(
526            script == HB_SCRIPT_ARABIC ||
527            script == HB_SCRIPT_NKO ||
528            script == HB_SCRIPT_PSALTER_PAHLAVI ||
529            script == HB_SCRIPT_MANDAIC ||
530            script == HB_SCRIPT_MONGOLIAN ||
531            script == HB_SCRIPT_PHAGS_PA ||
532            script == HB_SCRIPT_DEVANAGARI ||
533            script == HB_SCRIPT_BENGALI ||
534            script == HB_SCRIPT_GURMUKHI ||
535            script == HB_SCRIPT_MODI ||
536            script == HB_SCRIPT_SHARADA ||
537            script == HB_SCRIPT_SYLOTI_NAGRI ||
538            script == HB_SCRIPT_TIRHUTA ||
539            script == HB_SCRIPT_OGHAM
540            );
541}
542
543void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
544        int bidiFlags, const FontStyle &style, const MinikinPaint &paint) {
545    AutoMutex _l(gMinikinLock);
546
547    LayoutContext ctx;
548    ctx.style = style;
549    ctx.paint = paint;
550
551    bool isRtl = (bidiFlags & kDirection_Mask) != 0;
552    bool doSingleRun = true;
553
554    reset();
555    mAdvances.resize(count, 0);
556
557    if (!(bidiFlags == kBidi_Force_LTR || bidiFlags == kBidi_Force_RTL)) {
558        UBiDi* bidi = ubidi_open();
559        if (bidi) {
560            UErrorCode status = U_ZERO_ERROR;
561            UBiDiLevel bidiReq = bidiFlags;
562            if (bidiFlags == kBidi_Default_LTR) {
563                bidiReq = UBIDI_DEFAULT_LTR;
564            } else if (bidiFlags == kBidi_Default_RTL) {
565                bidiReq = UBIDI_DEFAULT_RTL;
566            }
567            ubidi_setPara(bidi, buf, bufSize, bidiReq, NULL, &status);
568            if (U_SUCCESS(status)) {
569                int paraDir = ubidi_getParaLevel(bidi) & kDirection_Mask;
570                ssize_t rc = ubidi_countRuns(bidi, &status);
571                if (!U_SUCCESS(status) || rc < 0) {
572                    ALOGW("error counting bidi runs, status = %d", status);
573                }
574                if (!U_SUCCESS(status) || rc <= 1) {
575                    isRtl = (paraDir == kBidi_RTL);
576                } else {
577                    doSingleRun = false;
578                    // iterate through runs
579                    for (ssize_t i = 0; i < (ssize_t)rc; i++) {
580                        int32_t startRun = -1;
581                        int32_t lengthRun = -1;
582                        UBiDiDirection runDir = ubidi_getVisualRun(bidi, i, &startRun, &lengthRun);
583                        if (startRun == -1 || lengthRun == -1) {
584                            ALOGE("invalid visual run");
585                            // skip the invalid run
586                            continue;
587                        }
588                        int32_t endRun = std::min(startRun + lengthRun, int32_t(start + count));
589                        startRun = std::max(startRun, int32_t(start));
590                        lengthRun = endRun - startRun;
591                        if (lengthRun > 0) {
592                            isRtl = (runDir == UBIDI_RTL);
593                            doLayoutRunCached(buf, startRun, lengthRun, bufSize, isRtl, &ctx,
594                                start);
595                        }
596                    }
597                }
598            } else {
599                ALOGE("error calling ubidi_setPara, status = %d", status);
600            }
601            ubidi_close(bidi);
602        } else {
603            ALOGE("error creating bidi object");
604        }
605    }
606    if (doSingleRun) {
607        doLayoutRunCached(buf, start, count, bufSize, isRtl, &ctx, start);
608    }
609    ctx.clearHbFonts();
610}
611
612void Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
613        bool isRtl, LayoutContext* ctx, size_t dstStart) {
614    HyphenEdit hyphen = ctx->paint.hyphenEdit;
615    if (!isRtl) {
616        // left to right
617        size_t wordstart = start == bufSize ? start : getPrevWordBreak(buf, start + 1);
618        size_t wordend;
619        for (size_t iter = start; iter < start + count; iter = wordend) {
620            wordend = getNextWordBreak(buf, iter, bufSize);
621            // Only apply hyphen to the last word in the string.
622            ctx->paint.hyphenEdit = wordend >= start + count ? hyphen : HyphenEdit();
623            size_t wordcount = std::min(start + count, wordend) - iter;
624            doLayoutWord(buf + wordstart, iter - wordstart, wordcount, wordend - wordstart,
625                    isRtl, ctx, iter - dstStart);
626            wordstart = wordend;
627        }
628    } else {
629        // right to left
630        size_t wordstart;
631        size_t end = start + count;
632        size_t wordend = end == 0 ? 0 : getNextWordBreak(buf, end - 1, bufSize);
633        for (size_t iter = end; iter > start; iter = wordstart) {
634            wordstart = getPrevWordBreak(buf, iter);
635            // Only apply hyphen to the last (leftmost) word in the string.
636            ctx->paint.hyphenEdit = iter == end ? hyphen : HyphenEdit();
637            size_t bufStart = std::max(start, wordstart);
638            doLayoutWord(buf + wordstart, bufStart - wordstart, iter - bufStart,
639                    wordend - wordstart, isRtl, ctx, bufStart - dstStart);
640            wordend = wordstart;
641        }
642    }
643}
644
645void Layout::doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
646        bool isRtl, LayoutContext* ctx, size_t bufStart) {
647    LayoutCache& cache = LayoutEngine::getInstance().layoutCache;
648    LayoutCacheKey key(mCollection, ctx->paint, ctx->style, buf, start, count, bufSize, isRtl);
649    bool skipCache = ctx->paint.skipCache();
650    if (skipCache) {
651        Layout layout;
652        key.doLayout(&layout, ctx, mCollection);
653        appendLayout(&layout, bufStart);
654    } else {
655        Layout* layout = cache.get(key, ctx, mCollection);
656        appendLayout(layout, bufStart);
657    }
658}
659
660static void addFeatures(const string &str, vector<hb_feature_t>* features) {
661    if (!str.size())
662        return;
663
664    const char* start = str.c_str();
665    const char* end = start + str.size();
666
667    while (start < end) {
668        static hb_feature_t feature;
669        const char* p = strchr(start, ',');
670        if (!p)
671            p = end;
672        /* We do not allow setting features on ranges.  As such, reject any
673         * setting that has non-universal range. */
674        if (hb_feature_from_string (start, p - start, &feature)
675                && feature.start == 0 && feature.end == (unsigned int) -1)
676            features->push_back(feature);
677        start = p + 1;
678    }
679}
680
681void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
682        bool isRtl, LayoutContext* ctx) {
683    hb_buffer_t* buffer = LayoutEngine::getInstance().hbBuffer;
684    vector<FontCollection::Run> items;
685    mCollection->itemize(buf + start, count, ctx->style, &items);
686    if (isRtl) {
687        std::reverse(items.begin(), items.end());
688    }
689
690    vector<hb_feature_t> features;
691    // Disable default-on non-required ligature features if letter-spacing
692    // See http://dev.w3.org/csswg/css-text-3/#letter-spacing-property
693    // "When the effective spacing between two characters is not zero (due to
694    // either justification or a non-zero value of letter-spacing), user agents
695    // should not apply optional ligatures."
696    if (fabs(ctx->paint.letterSpacing) > 0.03)
697    {
698        static const hb_feature_t no_liga = { HB_TAG('l', 'i', 'g', 'a'), 0, 0, ~0u };
699        static const hb_feature_t no_clig = { HB_TAG('c', 'l', 'i', 'g'), 0, 0, ~0u };
700        features.push_back(no_liga);
701        features.push_back(no_clig);
702    }
703    addFeatures(ctx->paint.fontFeatureSettings, &features);
704
705    double size = ctx->paint.size;
706    double scaleX = ctx->paint.scaleX;
707
708    float x = mAdvance;
709    float y = 0;
710    for (size_t run_ix = 0; run_ix < items.size(); run_ix++) {
711        FontCollection::Run &run = items[run_ix];
712        if (run.fakedFont.font == NULL) {
713            ALOGE("no font for run starting u+%04x length %d", buf[run.start], run.end - run.start);
714            continue;
715        }
716        int font_ix = findFace(run.fakedFont, ctx);
717        ctx->paint.font = mFaces[font_ix].font;
718        ctx->paint.fakery = mFaces[font_ix].fakery;
719        hb_font_t* hbFont = ctx->hbFonts[font_ix];
720#ifdef VERBOSE
721        std::cout << "Run " << run_ix << ", font " << font_ix <<
722            " [" << run.start << ":" << run.end << "]" << std::endl;
723#endif
724
725        hb_font_set_ppem(hbFont, size * scaleX, size);
726        hb_font_set_scale(hbFont, HBFloatToFixed(size * scaleX), HBFloatToFixed(size));
727
728        // TODO: if there are multiple scripts within a font in an RTL run,
729        // we need to reorder those runs. This is unlikely with our current
730        // font stack, but should be done for correctness.
731        ssize_t srunend;
732        for (ssize_t srunstart = run.start; srunstart < run.end; srunstart = srunend) {
733            srunend = srunstart;
734            hb_script_t script = getScriptRun(buf + start, run.end, &srunend);
735
736            double letterSpace = 0.0;
737            double letterSpaceHalfLeft = 0.0;
738            double letterSpaceHalfRight = 0.0;
739
740            if (ctx->paint.letterSpacing != 0.0 && isScriptOkForLetterspacing(script)) {
741                letterSpace = ctx->paint.letterSpacing * size * scaleX;
742                if ((ctx->paint.paintFlags & LinearTextFlag) == 0) {
743                    letterSpace = round(letterSpace);
744                    letterSpaceHalfLeft = floor(letterSpace * 0.5);
745                } else {
746                    letterSpaceHalfLeft = letterSpace * 0.5;
747                }
748                letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
749            }
750
751            hb_buffer_clear_contents(buffer);
752            hb_buffer_set_script(buffer, script);
753            hb_buffer_set_direction(buffer, isRtl? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
754            FontLanguage language = ctx->style.getLanguage();
755            if (language) {
756                string lang = language.getString();
757                hb_buffer_set_language(buffer, hb_language_from_string(lang.c_str(), -1));
758            }
759            hb_buffer_add_utf16(buffer, buf, bufSize, srunstart + start, srunend - srunstart);
760            if (ctx->paint.hyphenEdit.hasHyphen() && srunend > srunstart) {
761                // TODO: check whether this is really the desired semantics. It could have the
762                // effect of assigning the hyphen width to a nonspacing mark
763                unsigned int lastCluster = start + srunend - 1;
764
765                hb_codepoint_t hyphenChar = 0x2010; // HYPHEN
766                hb_codepoint_t glyph;
767                // Fallback to ASCII HYPHEN-MINUS if the font didn't have a glyph for HYPHEN. Note
768                // that we intentionally don't do anything special if the font doesn't have a
769                // HYPHEN-MINUS either, so a tofu could be shown, hinting towards something
770                // missing.
771                if (!hb_font_get_glyph(hbFont, hyphenChar, 0, &glyph)) {
772                    hyphenChar = 0x002D; // HYPHEN-MINUS
773                }
774                hb_buffer_add(buffer, hyphenChar, lastCluster);
775            }
776            hb_shape(hbFont, buffer, features.empty() ? NULL : &features[0], features.size());
777            unsigned int numGlyphs;
778            hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, &numGlyphs);
779            hb_glyph_position_t* positions = hb_buffer_get_glyph_positions(buffer, NULL);
780            if (numGlyphs)
781            {
782                mAdvances[info[0].cluster - start] += letterSpaceHalfLeft;
783                x += letterSpaceHalfLeft;
784            }
785            for (unsigned int i = 0; i < numGlyphs; i++) {
786    #ifdef VERBOSE
787                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 <<
788                ": " << HBFixedToFloat(positions[i].x_advance) << "; " << positions[i].x_offset << ", " << positions[i].y_offset << std::endl;
789    #endif
790                if (i > 0 && info[i - 1].cluster != info[i].cluster) {
791                    mAdvances[info[i - 1].cluster - start] += letterSpaceHalfRight;
792                    mAdvances[info[i].cluster - start] += letterSpaceHalfLeft;
793                    x += letterSpace;
794                }
795
796                hb_codepoint_t glyph_ix = info[i].codepoint;
797                float xoff = HBFixedToFloat(positions[i].x_offset);
798                float yoff = -HBFixedToFloat(positions[i].y_offset);
799                xoff += yoff * ctx->paint.skewX;
800                LayoutGlyph glyph = {font_ix, glyph_ix, x + xoff, y + yoff};
801                mGlyphs.push_back(glyph);
802                float xAdvance = HBFixedToFloat(positions[i].x_advance);
803                if ((ctx->paint.paintFlags & LinearTextFlag) == 0) {
804                    xAdvance = roundf(xAdvance);
805                }
806                MinikinRect glyphBounds;
807                ctx->paint.font->GetBounds(&glyphBounds, glyph_ix, ctx->paint);
808                glyphBounds.offset(x + xoff, y + yoff);
809                mBounds.join(glyphBounds);
810                if (info[i].cluster - start < count) {
811                    mAdvances[info[i].cluster - start] += xAdvance;
812                } else {
813                    ALOGE("cluster %d (start %d) out of bounds of count %d",
814                        info[i].cluster - start, start, count);
815                }
816                x += xAdvance;
817            }
818            if (numGlyphs)
819            {
820                mAdvances[info[numGlyphs - 1].cluster - start] += letterSpaceHalfRight;
821                x += letterSpaceHalfRight;
822            }
823        }
824    }
825    mAdvance = x;
826}
827
828void Layout::appendLayout(Layout* src, size_t start) {
829    int fontMapStack[16];
830    int* fontMap;
831    if (src->mFaces.size() < sizeof(fontMapStack) / sizeof(fontMapStack[0])) {
832        fontMap = fontMapStack;
833    } else {
834        fontMap = new int[src->mFaces.size()];
835    }
836    for (size_t i = 0; i < src->mFaces.size(); i++) {
837        int font_ix = findFace(src->mFaces[i], NULL);
838        fontMap[i] = font_ix;
839    }
840    int x0 = mAdvance;
841    for (size_t i = 0; i < src->mGlyphs.size(); i++) {
842        LayoutGlyph& srcGlyph = src->mGlyphs[i];
843        int font_ix = fontMap[srcGlyph.font_ix];
844        unsigned int glyph_id = srcGlyph.glyph_id;
845        float x = x0 + srcGlyph.x;
846        float y = srcGlyph.y;
847        LayoutGlyph glyph = {font_ix, glyph_id, x, y};
848        mGlyphs.push_back(glyph);
849    }
850    for (size_t i = 0; i < src->mAdvances.size(); i++) {
851        mAdvances[i + start] = src->mAdvances[i];
852    }
853    MinikinRect srcBounds(src->mBounds);
854    srcBounds.offset(x0, 0);
855    mBounds.join(srcBounds);
856    mAdvance += src->mAdvance;
857
858    if (fontMap != fontMapStack) {
859        delete[] fontMap;
860    }
861}
862
863void Layout::draw(minikin::Bitmap* surface, int x0, int y0, float size) const {
864    /*
865    TODO: redo as MinikinPaint settings
866    if (mProps.hasTag(minikinHinting)) {
867        int hintflags = mProps.value(minikinHinting).getIntValue();
868        if (hintflags & 1) load_flags |= FT_LOAD_NO_HINTING;
869        if (hintflags & 2) load_flags |= FT_LOAD_NO_AUTOHINT;
870    }
871    */
872    for (size_t i = 0; i < mGlyphs.size(); i++) {
873        const LayoutGlyph& glyph = mGlyphs[i];
874        MinikinFont* mf = mFaces[glyph.font_ix].font;
875        MinikinFontFreeType* face = static_cast<MinikinFontFreeType*>(mf);
876        GlyphBitmap glyphBitmap;
877        MinikinPaint paint;
878        paint.size = size;
879        bool ok = face->Render(glyph.glyph_id, paint, &glyphBitmap);
880        printf("glyphBitmap.width=%d, glyphBitmap.height=%d (%d, %d) x=%f, y=%f, ok=%d\n",
881            glyphBitmap.width, glyphBitmap.height, glyphBitmap.left, glyphBitmap.top, glyph.x, glyph.y, ok);
882        if (ok) {
883            surface->drawGlyph(glyphBitmap,
884                x0 + int(floor(glyph.x + 0.5)), y0 + int(floor(glyph.y + 0.5)));
885        }
886    }
887}
888
889size_t Layout::nGlyphs() const {
890    return mGlyphs.size();
891}
892
893MinikinFont* Layout::getFont(int i) const {
894    const LayoutGlyph& glyph = mGlyphs[i];
895    return mFaces[glyph.font_ix].font;
896}
897
898FontFakery Layout::getFakery(int i) const {
899    const LayoutGlyph& glyph = mGlyphs[i];
900    return mFaces[glyph.font_ix].fakery;
901}
902
903unsigned int Layout::getGlyphId(int i) const {
904    const LayoutGlyph& glyph = mGlyphs[i];
905    return glyph.glyph_id;
906}
907
908float Layout::getX(int i) const {
909    const LayoutGlyph& glyph = mGlyphs[i];
910    return glyph.x;
911}
912
913float Layout::getY(int i) const {
914    const LayoutGlyph& glyph = mGlyphs[i];
915    return glyph.y;
916}
917
918float Layout::getAdvance() const {
919    return mAdvance;
920}
921
922void Layout::getAdvances(float* advances) {
923    memcpy(advances, &mAdvances[0], mAdvances.size() * sizeof(float));
924}
925
926void Layout::getBounds(MinikinRect* bounds) {
927    bounds->set(mBounds);
928}
929
930void Layout::purgeCaches() {
931    AutoMutex _l(gMinikinLock);
932    LayoutCache& layoutCache = LayoutEngine::getInstance().layoutCache;
933    layoutCache.clear();
934    HbFaceCache& hbCache = LayoutEngine::getInstance().hbFaceCache;
935    hbCache.mCache.clear();
936}
937
938}  // namespace android
939