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      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 
     22 #include <algorithm>
     23 #include <fstream>
     24 #include <iostream>  // for debugging
     25 #include <string>
     26 #include <vector>
     27 
     28 #include <utils/JenkinsHash.h>
     29 #include <utils/LruCache.h>
     30 #include <utils/Singleton.h>
     31 #include <utils/String16.h>
     32 
     33 #include <unicode/ubidi.h>
     34 #include <hb-icu.h>
     35 #include <hb-ot.h>
     36 
     37 #include "FontLanguage.h"
     38 #include "FontLanguageListCache.h"
     39 #include "LayoutUtils.h"
     40 #include "HbFontCache.h"
     41 #include "MinikinInternal.h"
     42 #include <minikin/MinikinFontFreeType.h>
     43 #include <minikin/Layout.h>
     44 
     45 using std::string;
     46 using std::vector;
     47 
     48 namespace minikin {
     49 
     50 Bitmap::Bitmap(int width, int height) : width(width), height(height) {
     51     buf = new uint8_t[width * height]();
     52 }
     53 
     54 Bitmap::~Bitmap() {
     55     delete[] buf;
     56 }
     57 
     58 void Bitmap::writePnm(std::ofstream &o) const {
     59     o << "P5" << std::endl;
     60     o << width << " " << height << std::endl;
     61     o << "255" << std::endl;
     62     o.write((const char *)buf, width * height);
     63     o.close();
     64 }
     65 
     66 void Bitmap::drawGlyph(const android::GlyphBitmap& bitmap, int x, int y) {
     67     int bmw = bitmap.width;
     68     int bmh = bitmap.height;
     69     x += bitmap.left;
     70     y -= bitmap.top;
     71     int x0 = std::max(0, x);
     72     int x1 = std::min(width, x + bmw);
     73     int y0 = std::max(0, y);
     74     int y1 = std::min(height, y + bmh);
     75     const unsigned char* src = bitmap.buffer + (y0 - y) * bmw + (x0 - x);
     76     uint8_t* dst = buf + y0 * width;
     77     for (int yy = y0; yy < y1; yy++) {
     78         for (int xx = x0; xx < x1; xx++) {
     79             int pixel = (int)dst[xx] + (int)src[xx - x];
     80             pixel = pixel > 0xff ? 0xff : pixel;
     81             dst[xx] = pixel;
     82         }
     83         src += bmw;
     84         dst += width;
     85     }
     86 }
     87 
     88 } // namespace minikin
     89 
     90 namespace android {
     91 
     92 const int kDirection_Mask = 0x1;
     93 
     94 struct LayoutContext {
     95     MinikinPaint paint;
     96     FontStyle style;
     97     std::vector<hb_font_t*> hbFonts;  // parallel to mFaces
     98 
     99     void clearHbFonts() {
    100         for (size_t i = 0; i < hbFonts.size(); i++) {
    101             hb_font_set_funcs(hbFonts[i], nullptr, nullptr, nullptr);
    102             hb_font_destroy(hbFonts[i]);
    103         }
    104         hbFonts.clear();
    105     }
    106 };
    107 
    108 // Layout cache datatypes
    109 
    110 class LayoutCacheKey {
    111 public:
    112     LayoutCacheKey(const FontCollection* collection, const MinikinPaint& paint, FontStyle style,
    113             const uint16_t* chars, size_t start, size_t count, size_t nchars, bool dir)
    114             : mChars(chars), mNchars(nchars),
    115             mStart(start), mCount(count), mId(collection->getId()), mStyle(style),
    116             mSize(paint.size), mScaleX(paint.scaleX), mSkewX(paint.skewX),
    117             mLetterSpacing(paint.letterSpacing),
    118             mPaintFlags(paint.paintFlags), mHyphenEdit(paint.hyphenEdit), mIsRtl(dir),
    119             mHash(computeHash()) {
    120     }
    121     bool operator==(const LayoutCacheKey &other) const;
    122 
    123     hash_t hash() const {
    124         return mHash;
    125     }
    126 
    127     void copyText() {
    128         uint16_t* charsCopy = new uint16_t[mNchars];
    129         memcpy(charsCopy, mChars, mNchars * sizeof(uint16_t));
    130         mChars = charsCopy;
    131     }
    132     void freeText() {
    133         delete[] mChars;
    134         mChars = NULL;
    135     }
    136 
    137     void doLayout(Layout* layout, LayoutContext* ctx, const FontCollection* collection) const {
    138         layout->setFontCollection(collection);
    139         layout->mAdvances.resize(mCount, 0);
    140         ctx->clearHbFonts();
    141         layout->doLayoutRun(mChars, mStart, mCount, mNchars, mIsRtl, ctx);
    142     }
    143 
    144 private:
    145     const uint16_t* mChars;
    146     size_t mNchars;
    147     size_t mStart;
    148     size_t mCount;
    149     uint32_t mId;  // for the font collection
    150     FontStyle mStyle;
    151     float mSize;
    152     float mScaleX;
    153     float mSkewX;
    154     float mLetterSpacing;
    155     int32_t mPaintFlags;
    156     HyphenEdit mHyphenEdit;
    157     bool mIsRtl;
    158     // Note: any fields added to MinikinPaint must also be reflected here.
    159     // TODO: language matching (possibly integrate into style)
    160     hash_t mHash;
    161 
    162     hash_t computeHash() const;
    163 };
    164 
    165 class LayoutCache : private OnEntryRemoved<LayoutCacheKey, Layout*> {
    166 public:
    167     LayoutCache() : mCache(kMaxEntries) {
    168         mCache.setOnEntryRemovedListener(this);
    169     }
    170 
    171     void clear() {
    172         mCache.clear();
    173     }
    174 
    175     Layout* get(LayoutCacheKey& key, LayoutContext* ctx, const FontCollection* collection) {
    176         Layout* layout = mCache.get(key);
    177         if (layout == NULL) {
    178             key.copyText();
    179             layout = new Layout();
    180             key.doLayout(layout, ctx, collection);
    181             mCache.put(key, layout);
    182         }
    183         return layout;
    184     }
    185 
    186 private:
    187     // callback for OnEntryRemoved
    188     void operator()(LayoutCacheKey& key, Layout*& value) {
    189         key.freeText();
    190         delete value;
    191     }
    192 
    193     LruCache<LayoutCacheKey, Layout*> mCache;
    194 
    195     //static const size_t kMaxEntries = LruCache<LayoutCacheKey, Layout*>::kUnlimitedCapacity;
    196 
    197     // TODO: eviction based on memory footprint; for now, we just use a constant
    198     // number of strings
    199     static const size_t kMaxEntries = 5000;
    200 };
    201 
    202 static unsigned int disabledDecomposeCompatibility(hb_unicode_funcs_t*, hb_codepoint_t,
    203                                                    hb_codepoint_t*, void*) {
    204     return 0;
    205 }
    206 
    207 class LayoutEngine : public Singleton<LayoutEngine> {
    208 public:
    209     LayoutEngine() {
    210         unicodeFunctions = hb_unicode_funcs_create(hb_icu_get_unicode_funcs());
    211         /* Disable the function used for compatibility decomposition */
    212         hb_unicode_funcs_set_decompose_compatibility_func(
    213                 unicodeFunctions, disabledDecomposeCompatibility, NULL, NULL);
    214         hbBuffer = hb_buffer_create();
    215         hb_buffer_set_unicode_funcs(hbBuffer, unicodeFunctions);
    216     }
    217 
    218     hb_buffer_t* hbBuffer;
    219     hb_unicode_funcs_t* unicodeFunctions;
    220     LayoutCache layoutCache;
    221 };
    222 
    223 ANDROID_SINGLETON_STATIC_INSTANCE(LayoutEngine);
    224 
    225 bool LayoutCacheKey::operator==(const LayoutCacheKey& other) const {
    226     return mId == other.mId
    227             && mStart == other.mStart
    228             && mCount == other.mCount
    229             && mStyle == other.mStyle
    230             && mSize == other.mSize
    231             && mScaleX == other.mScaleX
    232             && mSkewX == other.mSkewX
    233             && mLetterSpacing == other.mLetterSpacing
    234             && mPaintFlags == other.mPaintFlags
    235             && mHyphenEdit == other.mHyphenEdit
    236             && mIsRtl == other.mIsRtl
    237             && mNchars == other.mNchars
    238             && !memcmp(mChars, other.mChars, mNchars * sizeof(uint16_t));
    239 }
    240 
    241 hash_t LayoutCacheKey::computeHash() const {
    242     uint32_t hash = JenkinsHashMix(0, mId);
    243     hash = JenkinsHashMix(hash, mStart);
    244     hash = JenkinsHashMix(hash, mCount);
    245     hash = JenkinsHashMix(hash, hash_type(mStyle));
    246     hash = JenkinsHashMix(hash, hash_type(mSize));
    247     hash = JenkinsHashMix(hash, hash_type(mScaleX));
    248     hash = JenkinsHashMix(hash, hash_type(mSkewX));
    249     hash = JenkinsHashMix(hash, hash_type(mLetterSpacing));
    250     hash = JenkinsHashMix(hash, hash_type(mPaintFlags));
    251     hash = JenkinsHashMix(hash, hash_type(mHyphenEdit.hasHyphen()));
    252     hash = JenkinsHashMix(hash, hash_type(mIsRtl));
    253     hash = JenkinsHashMixShorts(hash, mChars, mNchars);
    254     return JenkinsHashWhiten(hash);
    255 }
    256 
    257 hash_t hash_type(const LayoutCacheKey& key) {
    258     return key.hash();
    259 }
    260 
    261 void 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.
    273 void Layout::init() {
    274 }
    275 
    276 void Layout::reset() {
    277     mGlyphs.clear();
    278     mFaces.clear();
    279     mBounds.setEmpty();
    280     mAdvances.clear();
    281     mAdvance = 0;
    282 }
    283 
    284 void Layout::setFontCollection(const FontCollection* collection) {
    285     mCollection = collection;
    286 }
    287 
    288 static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* /* hbFont */, void* fontData,
    289         hb_codepoint_t glyph, void* /* userData */) {
    290     MinikinPaint* paint = reinterpret_cast<MinikinPaint*>(fontData);
    291     MinikinFont* font = paint->font;
    292     float advance = font->GetHorizontalAdvance(glyph, *paint);
    293     return 256 * advance + 0.5;
    294 }
    295 
    296 static hb_bool_t harfbuzzGetGlyphHorizontalOrigin(hb_font_t* /* hbFont */, void* /* fontData */,
    297         hb_codepoint_t /* glyph */, hb_position_t* /* x */, hb_position_t* /* y */,
    298         void* /* userData */) {
    299     // Just return true, following the way that Harfbuzz-FreeType
    300     // implementation does.
    301     return true;
    302 }
    303 
    304 hb_font_funcs_t* getHbFontFuncs() {
    305     static hb_font_funcs_t* hbFontFuncs = 0;
    306 
    307     if (hbFontFuncs == 0) {
    308         hbFontFuncs = hb_font_funcs_create();
    309         hb_font_funcs_set_glyph_h_advance_func(hbFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
    310         hb_font_funcs_set_glyph_h_origin_func(hbFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
    311         hb_font_funcs_make_immutable(hbFontFuncs);
    312     }
    313     return hbFontFuncs;
    314 }
    315 
    316 static float HBFixedToFloat(hb_position_t v)
    317 {
    318     return scalbnf (v, -8);
    319 }
    320 
    321 static hb_position_t HBFloatToFixed(float v)
    322 {
    323     return scalbnf (v, +8);
    324 }
    325 
    326 void Layout::dump() const {
    327     for (size_t i = 0; i < mGlyphs.size(); i++) {
    328         const LayoutGlyph& glyph = mGlyphs[i];
    329         std::cout << glyph.glyph_id << ": " << glyph.x << ", " << glyph.y << std::endl;
    330     }
    331 }
    332 
    333 int Layout::findFace(FakedFont face, LayoutContext* ctx) {
    334     unsigned int ix;
    335     for (ix = 0; ix < mFaces.size(); ix++) {
    336         if (mFaces[ix].font == face.font) {
    337             return ix;
    338         }
    339     }
    340     mFaces.push_back(face);
    341     // Note: ctx == NULL means we're copying from the cache, no need to create
    342     // corresponding hb_font object.
    343     if (ctx != NULL) {
    344         hb_font_t* font = getHbFontLocked(face.font);
    345         hb_font_set_funcs(font, getHbFontFuncs(), &ctx->paint, 0);
    346         ctx->hbFonts.push_back(font);
    347     }
    348     return ix;
    349 }
    350 
    351 static hb_script_t codePointToScript(hb_codepoint_t codepoint) {
    352     static hb_unicode_funcs_t* u = 0;
    353     if (!u) {
    354         u = LayoutEngine::getInstance().unicodeFunctions;
    355     }
    356     return hb_unicode_script(u, codepoint);
    357 }
    358 
    359 static hb_codepoint_t decodeUtf16(const uint16_t* chars, size_t len, ssize_t* iter) {
    360     const uint16_t v = chars[(*iter)++];
    361     // test whether v in (0xd800..0xdfff), lead or trail surrogate
    362     if ((v & 0xf800) == 0xd800) {
    363         // test whether v in (0xd800..0xdbff), lead surrogate
    364         if (size_t(*iter) < len && (v & 0xfc00) == 0xd800) {
    365             const uint16_t v2 = chars[(*iter)++];
    366             // test whether v2 in (0xdc00..0xdfff), trail surrogate
    367             if ((v2 & 0xfc00) == 0xdc00) {
    368                 // (0xd800 0xdc00) in utf-16 maps to 0x10000 in ucs-32
    369                 const hb_codepoint_t delta = (0xd800 << 10) + 0xdc00 - 0x10000;
    370                 return (((hb_codepoint_t)v) << 10) + v2 - delta;
    371             }
    372             (*iter) -= 1;
    373             return 0xFFFDu;
    374         } else {
    375             return 0xFFFDu;
    376         }
    377     } else {
    378         return v;
    379     }
    380 }
    381 
    382 static hb_script_t getScriptRun(const uint16_t* chars, size_t len, ssize_t* iter) {
    383     if (size_t(*iter) == len) {
    384         return HB_SCRIPT_UNKNOWN;
    385     }
    386     uint32_t cp = decodeUtf16(chars, len, iter);
    387     hb_script_t current_script = codePointToScript(cp);
    388     for (;;) {
    389         if (size_t(*iter) == len)
    390             break;
    391         const ssize_t prev_iter = *iter;
    392         cp = decodeUtf16(chars, len, iter);
    393         const hb_script_t script = codePointToScript(cp);
    394         if (script != current_script) {
    395             if (current_script == HB_SCRIPT_INHERITED ||
    396                 current_script == HB_SCRIPT_COMMON) {
    397                 current_script = script;
    398             } else if (script == HB_SCRIPT_INHERITED ||
    399                 script == HB_SCRIPT_COMMON) {
    400                 continue;
    401             } else {
    402                 *iter = prev_iter;
    403                 break;
    404             }
    405         }
    406     }
    407     if (current_script == HB_SCRIPT_INHERITED) {
    408         current_script = HB_SCRIPT_COMMON;
    409     }
    410 
    411     return current_script;
    412 }
    413 
    414 /**
    415  * Disable certain scripts (mostly those with cursive connection) from having letterspacing
    416  * applied. See https://github.com/behdad/harfbuzz/issues/64 for more details.
    417  */
    418 static bool isScriptOkForLetterspacing(hb_script_t script) {
    419     return !(
    420             script == HB_SCRIPT_ARABIC ||
    421             script == HB_SCRIPT_NKO ||
    422             script == HB_SCRIPT_PSALTER_PAHLAVI ||
    423             script == HB_SCRIPT_MANDAIC ||
    424             script == HB_SCRIPT_MONGOLIAN ||
    425             script == HB_SCRIPT_PHAGS_PA ||
    426             script == HB_SCRIPT_DEVANAGARI ||
    427             script == HB_SCRIPT_BENGALI ||
    428             script == HB_SCRIPT_GURMUKHI ||
    429             script == HB_SCRIPT_MODI ||
    430             script == HB_SCRIPT_SHARADA ||
    431             script == HB_SCRIPT_SYLOTI_NAGRI ||
    432             script == HB_SCRIPT_TIRHUTA ||
    433             script == HB_SCRIPT_OGHAM
    434             );
    435 }
    436 
    437 class BidiText {
    438 public:
    439     class Iter {
    440     public:
    441         struct RunInfo {
    442             int32_t mRunStart;
    443             int32_t mRunLength;
    444             bool mIsRtl;
    445         };
    446 
    447         Iter(UBiDi* bidi, size_t start, size_t end, size_t runIndex, size_t runCount, bool isRtl);
    448 
    449         bool operator!= (const Iter& other) const {
    450             return mIsEnd != other.mIsEnd || mNextRunIndex != other.mNextRunIndex
    451                     || mBidi != other.mBidi;
    452         }
    453 
    454         const RunInfo& operator* () const {
    455             return mRunInfo;
    456         }
    457 
    458         const Iter& operator++ () {
    459             updateRunInfo();
    460             return *this;
    461         }
    462 
    463     private:
    464         UBiDi* const mBidi;
    465         bool mIsEnd;
    466         size_t mNextRunIndex;
    467         const size_t mRunCount;
    468         const int32_t mStart;
    469         const int32_t mEnd;
    470         RunInfo mRunInfo;
    471 
    472         void updateRunInfo();
    473     };
    474 
    475     BidiText(const uint16_t* buf, size_t start, size_t count, size_t bufSize, int bidiFlags);
    476 
    477     ~BidiText() {
    478         if (mBidi) {
    479             ubidi_close(mBidi);
    480         }
    481     }
    482 
    483     Iter begin () const {
    484         return Iter(mBidi, mStart, mEnd, 0, mRunCount, mIsRtl);
    485     }
    486 
    487     Iter end() const {
    488         return Iter(mBidi, mStart, mEnd, mRunCount, mRunCount, mIsRtl);
    489     }
    490 
    491 private:
    492     const size_t mStart;
    493     const size_t mEnd;
    494     const size_t mBufSize;
    495     UBiDi* mBidi;
    496     size_t mRunCount;
    497     bool mIsRtl;
    498 
    499     DISALLOW_COPY_AND_ASSIGN(BidiText);
    500 };
    501 
    502 BidiText::Iter::Iter(UBiDi* bidi, size_t start, size_t end, size_t runIndex, size_t runCount,
    503         bool isRtl)
    504     : mBidi(bidi), mIsEnd(runIndex == runCount), mNextRunIndex(runIndex), mRunCount(runCount),
    505       mStart(start), mEnd(end), mRunInfo() {
    506     if (mRunCount == 1) {
    507         mRunInfo.mRunStart = start;
    508         mRunInfo.mRunLength = end - start;
    509         mRunInfo.mIsRtl = isRtl;
    510         mNextRunIndex = mRunCount;
    511         return;
    512     }
    513     updateRunInfo();
    514 }
    515 
    516 void BidiText::Iter::updateRunInfo() {
    517     if (mNextRunIndex == mRunCount) {
    518         // All runs have been iterated.
    519         mIsEnd = true;
    520         return;
    521     }
    522     int32_t startRun = -1;
    523     int32_t lengthRun = -1;
    524     const UBiDiDirection runDir = ubidi_getVisualRun(mBidi, mNextRunIndex, &startRun, &lengthRun);
    525     mNextRunIndex++;
    526     if (startRun == -1 || lengthRun == -1) {
    527         ALOGE("invalid visual run");
    528         // skip the invalid run.
    529         updateRunInfo();
    530         return;
    531     }
    532     const int32_t runEnd = std::min(startRun + lengthRun, mEnd);
    533     mRunInfo.mRunStart = std::max(startRun, mStart);
    534     mRunInfo.mRunLength = runEnd - mRunInfo.mRunStart;
    535     if (mRunInfo.mRunLength <= 0) {
    536         // skip the empty run.
    537         updateRunInfo();
    538         return;
    539     }
    540     mRunInfo.mIsRtl = (runDir == UBIDI_RTL);
    541 }
    542 
    543 BidiText::BidiText(const uint16_t* buf, size_t start, size_t count, size_t bufSize, int bidiFlags)
    544     : mStart(start), mEnd(start + count), mBufSize(bufSize), mBidi(NULL), mRunCount(1),
    545       mIsRtl((bidiFlags & kDirection_Mask) != 0) {
    546     if (bidiFlags == kBidi_Force_LTR || bidiFlags == kBidi_Force_RTL) {
    547         // force single run.
    548         return;
    549     }
    550     mBidi = ubidi_open();
    551     if (!mBidi) {
    552         ALOGE("error creating bidi object");
    553         return;
    554     }
    555     UErrorCode status = U_ZERO_ERROR;
    556     UBiDiLevel bidiReq = bidiFlags;
    557     if (bidiFlags == kBidi_Default_LTR) {
    558         bidiReq = UBIDI_DEFAULT_LTR;
    559     } else if (bidiFlags == kBidi_Default_RTL) {
    560         bidiReq = UBIDI_DEFAULT_RTL;
    561     }
    562     ubidi_setPara(mBidi, buf, mBufSize, bidiReq, NULL, &status);
    563     if (!U_SUCCESS(status)) {
    564         ALOGE("error calling ubidi_setPara, status = %d", status);
    565         return;
    566     }
    567     const int paraDir = ubidi_getParaLevel(mBidi) & kDirection_Mask;
    568     const ssize_t rc = ubidi_countRuns(mBidi, &status);
    569     if (!U_SUCCESS(status) || rc < 0) {
    570         ALOGW("error counting bidi runs, status = %d", status);
    571     }
    572     if (!U_SUCCESS(status) || rc <= 1) {
    573         mIsRtl = (paraDir == kBidi_RTL);
    574         return;
    575     }
    576     mRunCount = rc;
    577 }
    578 
    579 void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
    580         int bidiFlags, const FontStyle &style, const MinikinPaint &paint) {
    581     AutoMutex _l(gMinikinLock);
    582 
    583     LayoutContext ctx;
    584     ctx.style = style;
    585     ctx.paint = paint;
    586 
    587     reset();
    588     mAdvances.resize(count, 0);
    589 
    590     for (const BidiText::Iter::RunInfo& runInfo : BidiText(buf, start, count, bufSize, bidiFlags)) {
    591         doLayoutRunCached(buf, runInfo.mRunStart, runInfo.mRunLength, bufSize, runInfo.mIsRtl, &ctx,
    592                 start, mCollection, this, NULL);
    593     }
    594     ctx.clearHbFonts();
    595 }
    596 
    597 float Layout::measureText(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
    598         int bidiFlags, const FontStyle &style, const MinikinPaint &paint,
    599         const FontCollection* collection, float* advances) {
    600     AutoMutex _l(gMinikinLock);
    601 
    602     LayoutContext ctx;
    603     ctx.style = style;
    604     ctx.paint = paint;
    605 
    606     float advance = 0;
    607     for (const BidiText::Iter::RunInfo& runInfo : BidiText(buf, start, count, bufSize, bidiFlags)) {
    608         float* advancesForRun = advances ? advances + (runInfo.mRunStart - start) : advances;
    609         advance += doLayoutRunCached(buf, runInfo.mRunStart, runInfo.mRunLength, bufSize,
    610                 runInfo.mIsRtl, &ctx, 0, collection, NULL, advancesForRun);
    611     }
    612 
    613     ctx.clearHbFonts();
    614     return advance;
    615 }
    616 
    617 float Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
    618         bool isRtl, LayoutContext* ctx, size_t dstStart, const FontCollection* collection,
    619         Layout* layout, float* advances) {
    620     HyphenEdit hyphen = ctx->paint.hyphenEdit;
    621     float advance = 0;
    622     if (!isRtl) {
    623         // left to right
    624         size_t wordstart =
    625                 start == bufSize ? start : getPrevWordBreakForCache(buf, start + 1, bufSize);
    626         size_t wordend;
    627         for (size_t iter = start; iter < start + count; iter = wordend) {
    628             wordend = getNextWordBreakForCache(buf, iter, bufSize);
    629             // Only apply hyphen to the last word in the string.
    630             ctx->paint.hyphenEdit = wordend >= start + count ? hyphen : HyphenEdit();
    631             size_t wordcount = std::min(start + count, wordend) - iter;
    632             advance += doLayoutWord(buf + wordstart, iter - wordstart, wordcount,
    633                     wordend - wordstart, isRtl, ctx, iter - dstStart, collection, layout,
    634                     advances ? advances + (iter - start) : advances);
    635             wordstart = wordend;
    636         }
    637     } else {
    638         // right to left
    639         size_t wordstart;
    640         size_t end = start + count;
    641         size_t wordend = end == 0 ? 0 : getNextWordBreakForCache(buf, end - 1, bufSize);
    642         for (size_t iter = end; iter > start; iter = wordstart) {
    643             wordstart = getPrevWordBreakForCache(buf, iter, bufSize);
    644             // Only apply hyphen to the last (leftmost) word in the string.
    645             ctx->paint.hyphenEdit = iter == end ? hyphen : HyphenEdit();
    646             size_t bufStart = std::max(start, wordstart);
    647             advance += doLayoutWord(buf + wordstart, bufStart - wordstart, iter - bufStart,
    648                     wordend - wordstart, isRtl, ctx, bufStart - dstStart, collection, layout,
    649                     advances ? advances + (bufStart - start) : advances);
    650             wordend = wordstart;
    651         }
    652     }
    653     return advance;
    654 }
    655 
    656 float Layout::doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
    657         bool isRtl, LayoutContext* ctx, size_t bufStart, const FontCollection* collection,
    658         Layout* layout, float* advances) {
    659     LayoutCache& cache = LayoutEngine::getInstance().layoutCache;
    660     LayoutCacheKey key(collection, ctx->paint, ctx->style, buf, start, count, bufSize, isRtl);
    661     bool skipCache = ctx->paint.skipCache();
    662     if (skipCache) {
    663         Layout layoutForWord;
    664         key.doLayout(&layoutForWord, ctx, collection);
    665         if (layout) {
    666             layout->appendLayout(&layoutForWord, bufStart);
    667         }
    668         if (advances) {
    669             layoutForWord.getAdvances(advances);
    670         }
    671         return layoutForWord.getAdvance();
    672     } else {
    673         Layout* layoutForWord = cache.get(key, ctx, collection);
    674         if (layout) {
    675             layout->appendLayout(layoutForWord, bufStart);
    676         }
    677         if (advances) {
    678             layoutForWord->getAdvances(advances);
    679         }
    680         return layoutForWord->getAdvance();
    681     }
    682 }
    683 
    684 static void addFeatures(const string &str, vector<hb_feature_t>* features) {
    685     if (!str.size())
    686         return;
    687 
    688     const char* start = str.c_str();
    689     const char* end = start + str.size();
    690 
    691     while (start < end) {
    692         static hb_feature_t feature;
    693         const char* p = strchr(start, ',');
    694         if (!p)
    695             p = end;
    696         /* We do not allow setting features on ranges.  As such, reject any
    697          * setting that has non-universal range. */
    698         if (hb_feature_from_string (start, p - start, &feature)
    699                 && feature.start == 0 && feature.end == (unsigned int) -1)
    700             features->push_back(feature);
    701         start = p + 1;
    702     }
    703 }
    704 
    705 void Layout::doLayoutRun(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
    706         bool isRtl, LayoutContext* ctx) {
    707     hb_buffer_t* buffer = LayoutEngine::getInstance().hbBuffer;
    708     vector<FontCollection::Run> items;
    709     mCollection->itemize(buf + start, count, ctx->style, &items);
    710     if (isRtl) {
    711         std::reverse(items.begin(), items.end());
    712     }
    713 
    714     vector<hb_feature_t> features;
    715     // Disable default-on non-required ligature features if letter-spacing
    716     // See http://dev.w3.org/csswg/css-text-3/#letter-spacing-property
    717     // "When the effective spacing between two characters is not zero (due to
    718     // either justification or a non-zero value of letter-spacing), user agents
    719     // should not apply optional ligatures."
    720     if (fabs(ctx->paint.letterSpacing) > 0.03)
    721     {
    722         static const hb_feature_t no_liga = { HB_TAG('l', 'i', 'g', 'a'), 0, 0, ~0u };
    723         static const hb_feature_t no_clig = { HB_TAG('c', 'l', 'i', 'g'), 0, 0, ~0u };
    724         features.push_back(no_liga);
    725         features.push_back(no_clig);
    726     }
    727     addFeatures(ctx->paint.fontFeatureSettings, &features);
    728 
    729     double size = ctx->paint.size;
    730     double scaleX = ctx->paint.scaleX;
    731 
    732     float x = mAdvance;
    733     float y = 0;
    734     for (size_t run_ix = 0; run_ix < items.size(); run_ix++) {
    735         FontCollection::Run &run = items[run_ix];
    736         if (run.fakedFont.font == NULL) {
    737             ALOGE("no font for run starting u+%04x length %d", buf[run.start], run.end - run.start);
    738             continue;
    739         }
    740         int font_ix = findFace(run.fakedFont, ctx);
    741         ctx->paint.font = mFaces[font_ix].font;
    742         ctx->paint.fakery = mFaces[font_ix].fakery;
    743         hb_font_t* hbFont = ctx->hbFonts[font_ix];
    744 #ifdef VERBOSE_DEBUG
    745         ALOGD("Run %zu, font %d [%d:%d]", run_ix, font_ix, run.start, run.end);
    746 #endif
    747 
    748         hb_font_set_ppem(hbFont, size * scaleX, size);
    749         hb_font_set_scale(hbFont, HBFloatToFixed(size * scaleX), HBFloatToFixed(size));
    750 
    751         // TODO: if there are multiple scripts within a font in an RTL run,
    752         // we need to reorder those runs. This is unlikely with our current
    753         // font stack, but should be done for correctness.
    754         ssize_t srunend;
    755         for (ssize_t srunstart = run.start; srunstart < run.end; srunstart = srunend) {
    756             srunend = srunstart;
    757             hb_script_t script = getScriptRun(buf + start, run.end, &srunend);
    758 
    759             double letterSpace = 0.0;
    760             double letterSpaceHalfLeft = 0.0;
    761             double letterSpaceHalfRight = 0.0;
    762 
    763             if (ctx->paint.letterSpacing != 0.0 && isScriptOkForLetterspacing(script)) {
    764                 letterSpace = ctx->paint.letterSpacing * size * scaleX;
    765                 if ((ctx->paint.paintFlags & LinearTextFlag) == 0) {
    766                     letterSpace = round(letterSpace);
    767                     letterSpaceHalfLeft = floor(letterSpace * 0.5);
    768                 } else {
    769                     letterSpaceHalfLeft = letterSpace * 0.5;
    770                 }
    771                 letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
    772             }
    773 
    774             hb_buffer_clear_contents(buffer);
    775             hb_buffer_set_script(buffer, script);
    776             hb_buffer_set_direction(buffer, isRtl? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
    777             const FontLanguages& langList =
    778                     FontLanguageListCache::getById(ctx->style.getLanguageListId());
    779             if (langList.size() != 0) {
    780                 const FontLanguage* hbLanguage = &langList[0];
    781                 for (size_t i = 0; i < langList.size(); ++i) {
    782                     if (langList[i].supportsHbScript(script)) {
    783                         hbLanguage = &langList[i];
    784                         break;
    785                     }
    786                 }
    787                 hb_buffer_set_language(buffer,
    788                         hb_language_from_string(hbLanguage->getString().c_str(), -1));
    789             }
    790             hb_buffer_add_utf16(buffer, buf, bufSize, srunstart + start, srunend - srunstart);
    791             if (ctx->paint.hyphenEdit.hasHyphen() && srunend > srunstart) {
    792                 // TODO: check whether this is really the desired semantics. It could have the
    793                 // effect of assigning the hyphen width to a nonspacing mark
    794                 unsigned int lastCluster = start + srunend - 1;
    795 
    796                 hb_codepoint_t hyphenChar = 0x2010; // HYPHEN
    797                 hb_codepoint_t glyph;
    798                 // Fallback to ASCII HYPHEN-MINUS if the font didn't have a glyph for HYPHEN. Note
    799                 // that we intentionally don't do anything special if the font doesn't have a
    800                 // HYPHEN-MINUS either, so a tofu could be shown, hinting towards something
    801                 // missing.
    802                 if (!hb_font_get_glyph(hbFont, hyphenChar, 0, &glyph)) {
    803                     hyphenChar = 0x002D; // HYPHEN-MINUS
    804                 }
    805                 hb_buffer_add(buffer, hyphenChar, lastCluster);
    806             }
    807             hb_shape(hbFont, buffer, features.empty() ? NULL : &features[0], features.size());
    808             unsigned int numGlyphs;
    809             hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, &numGlyphs);
    810             hb_glyph_position_t* positions = hb_buffer_get_glyph_positions(buffer, NULL);
    811             if (numGlyphs)
    812             {
    813                 mAdvances[info[0].cluster - start] += letterSpaceHalfLeft;
    814                 x += letterSpaceHalfLeft;
    815             }
    816             for (unsigned int i = 0; i < numGlyphs; i++) {
    817 #ifdef VERBOSE_DEBUG
    818                 ALOGD("%d %d %d %d",
    819                         positions[i].x_advance, positions[i].y_advance,
    820                         positions[i].x_offset, positions[i].y_offset);
    821                 ALOGD("DoLayout %u: %f; %d, %d",
    822                         info[i].codepoint, HBFixedToFloat(positions[i].x_advance),
    823                         positions[i].x_offset, positions[i].y_offset);
    824 #endif
    825                 if (i > 0 && info[i - 1].cluster != info[i].cluster) {
    826                     mAdvances[info[i - 1].cluster - start] += letterSpaceHalfRight;
    827                     mAdvances[info[i].cluster - start] += letterSpaceHalfLeft;
    828                     x += letterSpace;
    829                 }
    830 
    831                 hb_codepoint_t glyph_ix = info[i].codepoint;
    832                 float xoff = HBFixedToFloat(positions[i].x_offset);
    833                 float yoff = -HBFixedToFloat(positions[i].y_offset);
    834                 xoff += yoff * ctx->paint.skewX;
    835                 LayoutGlyph glyph = {font_ix, glyph_ix, x + xoff, y + yoff};
    836                 mGlyphs.push_back(glyph);
    837                 float xAdvance = HBFixedToFloat(positions[i].x_advance);
    838                 if ((ctx->paint.paintFlags & LinearTextFlag) == 0) {
    839                     xAdvance = roundf(xAdvance);
    840                 }
    841                 MinikinRect glyphBounds;
    842                 ctx->paint.font->GetBounds(&glyphBounds, glyph_ix, ctx->paint);
    843                 glyphBounds.offset(x + xoff, y + yoff);
    844                 mBounds.join(glyphBounds);
    845                 if (info[i].cluster - start < count) {
    846                     mAdvances[info[i].cluster - start] += xAdvance;
    847                 } else {
    848                     ALOGE("cluster %zu (start %zu) out of bounds of count %zu",
    849                         info[i].cluster - start, start, count);
    850                 }
    851                 x += xAdvance;
    852             }
    853             if (numGlyphs)
    854             {
    855                 mAdvances[info[numGlyphs - 1].cluster - start] += letterSpaceHalfRight;
    856                 x += letterSpaceHalfRight;
    857             }
    858         }
    859     }
    860     mAdvance = x;
    861 }
    862 
    863 void Layout::appendLayout(Layout* src, size_t start) {
    864     int fontMapStack[16];
    865     int* fontMap;
    866     if (src->mFaces.size() < sizeof(fontMapStack) / sizeof(fontMapStack[0])) {
    867         fontMap = fontMapStack;
    868     } else {
    869         fontMap = new int[src->mFaces.size()];
    870     }
    871     for (size_t i = 0; i < src->mFaces.size(); i++) {
    872         int font_ix = findFace(src->mFaces[i], NULL);
    873         fontMap[i] = font_ix;
    874     }
    875     int x0 = mAdvance;
    876     for (size_t i = 0; i < src->mGlyphs.size(); i++) {
    877         LayoutGlyph& srcGlyph = src->mGlyphs[i];
    878         int font_ix = fontMap[srcGlyph.font_ix];
    879         unsigned int glyph_id = srcGlyph.glyph_id;
    880         float x = x0 + srcGlyph.x;
    881         float y = srcGlyph.y;
    882         LayoutGlyph glyph = {font_ix, glyph_id, x, y};
    883         mGlyphs.push_back(glyph);
    884     }
    885     for (size_t i = 0; i < src->mAdvances.size(); i++) {
    886         mAdvances[i + start] = src->mAdvances[i];
    887     }
    888     MinikinRect srcBounds(src->mBounds);
    889     srcBounds.offset(x0, 0);
    890     mBounds.join(srcBounds);
    891     mAdvance += src->mAdvance;
    892 
    893     if (fontMap != fontMapStack) {
    894         delete[] fontMap;
    895     }
    896 }
    897 
    898 void Layout::draw(minikin::Bitmap* surface, int x0, int y0, float size) const {
    899     /*
    900     TODO: redo as MinikinPaint settings
    901     if (mProps.hasTag(minikinHinting)) {
    902         int hintflags = mProps.value(minikinHinting).getIntValue();
    903         if (hintflags & 1) load_flags |= FT_LOAD_NO_HINTING;
    904         if (hintflags & 2) load_flags |= FT_LOAD_NO_AUTOHINT;
    905     }
    906     */
    907     for (size_t i = 0; i < mGlyphs.size(); i++) {
    908         const LayoutGlyph& glyph = mGlyphs[i];
    909         MinikinFont* mf = mFaces[glyph.font_ix].font;
    910         MinikinFontFreeType* face = static_cast<MinikinFontFreeType*>(mf);
    911         GlyphBitmap glyphBitmap;
    912         MinikinPaint paint;
    913         paint.size = size;
    914         bool ok = face->Render(glyph.glyph_id, paint, &glyphBitmap);
    915 #ifdef VERBOSE_DEBUG
    916         ALOGD("glyphBitmap.width=%d, glyphBitmap.height=%d (%d, %d) x=%f, y=%f, ok=%d",
    917             glyphBitmap.width, glyphBitmap.height, glyphBitmap.left, glyphBitmap.top, glyph.x, glyph.y, ok);
    918 #endif
    919         if (ok) {
    920             surface->drawGlyph(glyphBitmap,
    921                 x0 + int(floor(glyph.x + 0.5)), y0 + int(floor(glyph.y + 0.5)));
    922         }
    923     }
    924 }
    925 
    926 size_t Layout::nGlyphs() const {
    927     return mGlyphs.size();
    928 }
    929 
    930 MinikinFont* Layout::getFont(int i) const {
    931     const LayoutGlyph& glyph = mGlyphs[i];
    932     return mFaces[glyph.font_ix].font;
    933 }
    934 
    935 FontFakery Layout::getFakery(int i) const {
    936     const LayoutGlyph& glyph = mGlyphs[i];
    937     return mFaces[glyph.font_ix].fakery;
    938 }
    939 
    940 unsigned int Layout::getGlyphId(int i) const {
    941     const LayoutGlyph& glyph = mGlyphs[i];
    942     return glyph.glyph_id;
    943 }
    944 
    945 float Layout::getX(int i) const {
    946     const LayoutGlyph& glyph = mGlyphs[i];
    947     return glyph.x;
    948 }
    949 
    950 float Layout::getY(int i) const {
    951     const LayoutGlyph& glyph = mGlyphs[i];
    952     return glyph.y;
    953 }
    954 
    955 float Layout::getAdvance() const {
    956     return mAdvance;
    957 }
    958 
    959 void Layout::getAdvances(float* advances) {
    960     memcpy(advances, &mAdvances[0], mAdvances.size() * sizeof(float));
    961 }
    962 
    963 void Layout::getBounds(MinikinRect* bounds) {
    964     bounds->set(mBounds);
    965 }
    966 
    967 void Layout::purgeCaches() {
    968     AutoMutex _l(gMinikinLock);
    969     LayoutCache& layoutCache = LayoutEngine::getInstance().layoutCache;
    970     layoutCache.clear();
    971     purgeHbFontCacheLocked();
    972 }
    973 
    974 }  // namespace android
    975