DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (c68fe15a81fc)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240
/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "src/utils/win/SkDWriteNTDDI_VERSION.h"

#include "include/core/SkTypes.h"
#if defined(SK_BUILD_FOR_WIN)

#undef GetGlyphIndices

#include "include/codec/SkCodec.h"
#include "include/core/SkFontMetrics.h"
#include "include/core/SkPath.h"
#include "include/private/SkMutex.h"
#include "include/private/SkTo.h"
#include "src/core/SkDraw.h"
#include "src/core/SkEndian.h"
#include "src/core/SkGlyph.h"
#include "src/core/SkMaskGamma.h"
#include "src/core/SkRasterClip.h"
#include "src/core/SkScalerContext.h"
#include "src/core/SkSharedMutex.h"
#include "src/ports/SkScalerContext_win_dw.h"
#include "src/ports/SkTypeface_win_dw.h"
#include "src/sfnt/SkOTTable_EBLC.h"
#include "src/sfnt/SkOTTable_EBSC.h"
#include "src/sfnt/SkOTTable_gasp.h"
#include "src/sfnt/SkOTTable_maxp.h"
#include "src/utils/SkMatrix22.h"
#include "src/utils/win/SkDWrite.h"
#include "src/utils/win/SkDWriteGeometrySink.h"
#include "src/utils/win/SkHRESULT.h"
#include "src/utils/win/SkTScopedComPtr.h"

#include <dwrite.h>
#include <dwrite_1.h>
#include <dwrite_3.h>

/* Note:
 * In versions 8 and 8.1 of Windows, some calls in DWrite are not thread safe.
 * The DWriteFactoryMutex protects the calls that are problematic.
 *
 * On DWrite 3 or above, which is only available on Windows 10, we don't enable
 * the locking to avoid thread contention.
 */
static SkSharedMutex DWriteFactoryMutex;

struct MaybeExclusive {
    MaybeExclusive(SkScalerContext_DW* ctx) : fEnabled(!ctx->isDWrite3()) {
        if (fEnabled) {
            DWriteFactoryMutex.acquire();
        }
    }
    ~MaybeExclusive() {
        if (fEnabled) {
            DWriteFactoryMutex.release();
        }
    }
    bool fEnabled;
};

struct MaybeShared {
    MaybeShared(SkScalerContext_DW* ctx) : fEnabled(!ctx->isDWrite3()) {
        if (fEnabled) {
            DWriteFactoryMutex.acquireShared();
        }
    }
    ~MaybeShared() {
        if (fEnabled) {
            DWriteFactoryMutex.releaseShared();
        }
    }
    bool fEnabled;
};

static bool isLCD(const SkScalerContextRec& rec) {
    return SkMask::kLCD16_Format == rec.fMaskFormat;
}

static bool is_hinted(SkScalerContext_DW* ctx, DWriteFontTypeface* typeface) {
    MaybeExclusive l(ctx);
    AutoTDWriteTable<SkOTTableMaximumProfile> maxp(typeface->fDWriteFontFace.get());
    if (!maxp.fExists) {
        return false;
    }
    if (maxp.fSize < sizeof(SkOTTableMaximumProfile::Version::TT)) {
        return false;
    }
    if (maxp->version.version != SkOTTableMaximumProfile::Version::TT::VERSION) {
        return false;
    }
    return (0 != maxp->version.tt.maxSizeOfInstructions);
}

/** A GaspRange is inclusive, [min, max]. */
struct GaspRange {
    using Behavior = SkOTTableGridAndScanProcedure::GaspRange::behavior;
    GaspRange(int min, int max, int version, Behavior flags)
        : fMin(min), fMax(max), fVersion(version), fFlags(flags) { }
    int fMin;
    int fMax;
    int fVersion;
    Behavior fFlags;
};

bool get_gasp_range(DWriteFontTypeface* typeface, int size, GaspRange* range) {
    AutoTDWriteTable<SkOTTableGridAndScanProcedure> gasp(typeface->fDWriteFontFace.get());
    if (!gasp.fExists) {
        return false;
    }
    if (gasp.fSize < sizeof(SkOTTableGridAndScanProcedure)) {
        return false;
    }
    if (gasp->version != SkOTTableGridAndScanProcedure::version0 &&
        gasp->version != SkOTTableGridAndScanProcedure::version1)
    {
        return false;
    }

    uint16_t numRanges = SkEndianSwap16(gasp->numRanges);
    if (numRanges > 1024 ||
        gasp.fSize < sizeof(SkOTTableGridAndScanProcedure) +
        sizeof(SkOTTableGridAndScanProcedure::GaspRange) * numRanges)
    {
        return false;
    }

    const SkOTTableGridAndScanProcedure::GaspRange* rangeTable =
            SkTAfter<const SkOTTableGridAndScanProcedure::GaspRange>(gasp.get());
    int minPPEM = -1;
    for (uint16_t i = 0; i < numRanges; ++i, ++rangeTable) {
        int maxPPEM = SkEndianSwap16(rangeTable->maxPPEM);
        if (minPPEM < size && size <= maxPPEM) {
            range->fMin = minPPEM + 1;
            range->fMax = maxPPEM;
            range->fVersion = SkEndian_SwapBE16(gasp->version);
            range->fFlags = rangeTable->flags;
            return true;
        }
        minPPEM = maxPPEM;
    }
    return false;
}
/** If the rendering mode for the specified 'size' is gridfit, then place
 *  the gridfit range into 'range'. Otherwise, leave 'range' alone.
 */
static bool is_gridfit_only(GaspRange::Behavior flags) {
    return flags.raw.value == GaspRange::Behavior::Raw::GridfitMask;
}

static bool has_bitmap_strike(SkScalerContext_DW* ctx, DWriteFontTypeface* typeface, GaspRange range) {
    MaybeExclusive l(ctx);
    {
        AutoTDWriteTable<SkOTTableEmbeddedBitmapLocation> eblc(typeface->fDWriteFontFace.get());
        if (!eblc.fExists) {
            return false;
        }
        if (eblc.fSize < sizeof(SkOTTableEmbeddedBitmapLocation)) {
            return false;
        }
        if (eblc->version != SkOTTableEmbeddedBitmapLocation::version_initial) {
            return false;
        }

        uint32_t numSizes = SkEndianSwap32(eblc->numSizes);
        if (numSizes > 1024 ||
            eblc.fSize < sizeof(SkOTTableEmbeddedBitmapLocation) +
                         sizeof(SkOTTableEmbeddedBitmapLocation::BitmapSizeTable) * numSizes)
        {
            return false;
        }

        const SkOTTableEmbeddedBitmapLocation::BitmapSizeTable* sizeTable =
                SkTAfter<const SkOTTableEmbeddedBitmapLocation::BitmapSizeTable>(eblc.get());
        for (uint32_t i = 0; i < numSizes; ++i, ++sizeTable) {
            if (sizeTable->ppemX == sizeTable->ppemY &&
                range.fMin <= sizeTable->ppemX && sizeTable->ppemX <= range.fMax)
            {
                // TODO: determine if we should dig through IndexSubTableArray/IndexSubTable
                // to determine the actual number of glyphs with bitmaps.

                // TODO: Ensure that the bitmaps actually cover a significant portion of the strike.

                // TODO: Ensure that the bitmaps are bi-level?
                if (sizeTable->endGlyphIndex >= sizeTable->startGlyphIndex + 3) {
                    return true;
                }
            }
        }
    }

    {
        AutoTDWriteTable<SkOTTableEmbeddedBitmapScaling> ebsc(typeface->fDWriteFontFace.get());
        if (!ebsc.fExists) {
            return false;
        }
        if (ebsc.fSize < sizeof(SkOTTableEmbeddedBitmapScaling)) {
            return false;
        }
        if (ebsc->version != SkOTTableEmbeddedBitmapScaling::version_initial) {
            return false;
        }

        uint32_t numSizes = SkEndianSwap32(ebsc->numSizes);
        if (numSizes > 1024 ||
            ebsc.fSize < sizeof(SkOTTableEmbeddedBitmapScaling) +
                         sizeof(SkOTTableEmbeddedBitmapScaling::BitmapScaleTable) * numSizes)
        {
            return false;
        }

        const SkOTTableEmbeddedBitmapScaling::BitmapScaleTable* scaleTable =
                SkTAfter<const SkOTTableEmbeddedBitmapScaling::BitmapScaleTable>(ebsc.get());
        for (uint32_t i = 0; i < numSizes; ++i, ++scaleTable) {
            if (scaleTable->ppemX == scaleTable->ppemY &&
                range.fMin <= scaleTable->ppemX && scaleTable->ppemX <= range.fMax) {
                // EBSC tables are normally only found in bitmap only fonts.
                return true;
            }
        }
    }

    return false;
}

static bool both_zero(SkScalar a, SkScalar b) {
    return 0 == a && 0 == b;
}

// returns false if there is any non-90-rotation or skew
static bool is_axis_aligned(const SkScalerContextRec& rec) {
    return 0 == rec.fPreSkewX &&
           (both_zero(rec.fPost2x2[0][1], rec.fPost2x2[1][0]) ||
            both_zero(rec.fPost2x2[0][0], rec.fPost2x2[1][1]));
}

SkScalerContext_DW::SkScalerContext_DW(sk_sp<DWriteFontTypeface> typefaceRef,
                                       const SkScalerContextEffects& effects,
                                       const SkDescriptor* desc)
        : SkScalerContext(std::move(typefaceRef), effects, desc)
        , fGlyphCount(-1) {

    DWriteFontTypeface* typeface = this->getDWriteTypeface();
    fIsColorFont = typeface->fFactory2 &&
                   typeface->fDWriteFontFace2 &&
                   typeface->fDWriteFontFace2->IsColorFont();
    fClearTypeLevel = int(typeface->GetClearTypeLevel() * 256);

    // In general, all glyphs should use DWriteFontFace::GetRecommendedRenderingMode
    // except when bi-level rendering is requested or there are embedded
    // bi-level bitmaps (and the embedded bitmap flag is set and no rotation).
    //
    // DirectWrite's IDWriteFontFace::GetRecommendedRenderingMode does not do
    // this. As a result, determine the actual size of the text and then see if
    // there are any embedded bi-level bitmaps of that size. If there are, then
    // force bitmaps by requesting bi-level rendering.
    //
    // FreeType allows for separate ppemX and ppemY, but DirectWrite assumes
    // square pixels and only uses ppemY. Therefore the transform must track any
    // non-uniform x-scale.
    //
    // Also, rotated glyphs should have the same absolute advance widths as
    // horizontal glyphs and the subpixel flag should not affect glyph shapes.

    SkVector scale;
    fRec.computeMatrices(SkScalerContextRec::kVertical_PreMatrixScale, &scale, &fSkXform);

    fXform.m11 = SkScalarToFloat(fSkXform.getScaleX());
    fXform.m12 = SkScalarToFloat(fSkXform.getSkewY());
    fXform.m21 = SkScalarToFloat(fSkXform.getSkewX());
    fXform.m22 = SkScalarToFloat(fSkXform.getScaleY());
    fXform.dx = 0;
    fXform.dy = 0;

    // realTextSize is the actual device size we want (as opposed to the size the user requested).
    // gdiTextSize is the size we request when GDI compatible.
    // If the scale is negative, this means the matrix will do the flip anyway.
    const SkScalar realTextSize = scale.fY;
    // Due to floating point math, the lower bits are suspect. Round carefully.
    SkScalar gdiTextSize = SkScalarRoundToScalar(realTextSize * 64.0f) / 64.0f;
    if (gdiTextSize == 0) {
        gdiTextSize = SK_Scalar1;
    }

    bool bitmapRequested = SkToBool(fRec.fFlags & SkScalerContext::kEmbeddedBitmapText_Flag);
    bool treatLikeBitmap = false;
    bool axisAlignedBitmap = false;
    if (bitmapRequested) {
        // When embedded bitmaps are requested, treat the entire range like
        // a bitmap strike if the range is gridfit only and contains a bitmap.
        int bitmapPPEM = SkScalarTruncToInt(gdiTextSize);
        GaspRange range(bitmapPPEM, bitmapPPEM, 0, GaspRange::Behavior());
        if (get_gasp_range(typeface, bitmapPPEM, &range)) {
            if (!is_gridfit_only(range.fFlags)) {
                range = GaspRange(bitmapPPEM, bitmapPPEM, 0, GaspRange::Behavior());
            }
        }
        treatLikeBitmap = has_bitmap_strike(this, typeface, range);

        axisAlignedBitmap = is_axis_aligned(fRec);
    }

    GaspRange range(0, 0xFFFF, 0, GaspRange::Behavior());

    // If the user requested aliased, do so with aliased compatible metrics.
    if (SkMask::kBW_Format == fRec.fMaskFormat) {
        fTextSizeRender = gdiTextSize;
        fRenderingMode = DWRITE_RENDERING_MODE_ALIASED;
        fTextureType = DWRITE_TEXTURE_ALIASED_1x1;
        fTextSizeMeasure = gdiTextSize;
        fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;

    // If we can use a bitmap, use gdi classic rendering and measurement.
    // This will not always provide a bitmap, but matches expected behavior.
    } else if ((treatLikeBitmap && axisAlignedBitmap) || typeface->ForceGDI()) {
        fTextSizeRender = gdiTextSize;
        fRenderingMode = DWRITE_RENDERING_MODE_GDI_CLASSIC;
        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
        fTextSizeMeasure = gdiTextSize;
        fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;

    // If rotated but the horizontal text could have used a bitmap,
    // render high quality rotated glyphs but measure using bitmap metrics.
    } else if (treatLikeBitmap) {
        fTextSizeRender = gdiTextSize;
        fRenderingMode = DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC;
        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
        fTextSizeMeasure = gdiTextSize;
        fMeasuringMode = DWRITE_MEASURING_MODE_GDI_CLASSIC;

    // If the font has a gasp table version 1, use it to determine symmetric rendering.
    } else if ((get_gasp_range(typeface, SkScalarRoundToInt(gdiTextSize), &range) &&
                range.fVersion >= 1) ||
               realTextSize > SkIntToScalar(20) || !is_hinted(this, typeface)) {
        fTextSizeRender = realTextSize;
        fRenderingMode = DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC;
        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
        fTextSizeMeasure = realTextSize;
        fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;

        switch (typeface->GetRenderingMode()) {
        case DWRITE_RENDERING_MODE_NATURAL:
        case DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC:
            fRenderingMode = typeface->GetRenderingMode();
            break;
        default:
            if (IDWriteRenderingParams* params = sk_get_dwrite_default_rendering_params()) {
                typeface->fDWriteFontFace->GetRecommendedRenderingMode(
                    fTextSizeRender, 1.0f, fMeasuringMode, params, &fRenderingMode);
            }
            break;
        }

        // We don't support outline mode right now.
        if (fRenderingMode == DWRITE_RENDERING_MODE_OUTLINE) {
            fRenderingMode = DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
        }

    // Fonts with hints, no gasp or gasp version 0, and below 20px get non-symmetric rendering.
    // Often such fonts have hints which were only tested with GDI ClearType classic.
    // Some of these fonts rely on drop out control in the y direction in order to be legible.
    // Tenor Sans
    //    https://fonts.google.com/specimen/Tenor+Sans
    // Gill Sans W04
    //    https://cdn.leagueoflegends.com/lolkit/1.1.9/resources/fonts/gill-sans-w04-book.woff
    //    https://na.leagueoflegends.com/en/news/game-updates/patch/patch-410-notes
    // See https://crbug.com/385897
    } else {
        fTextSizeRender = gdiTextSize;
        fRenderingMode = DWRITE_RENDERING_MODE_NATURAL;
        fTextureType = DWRITE_TEXTURE_CLEARTYPE_3x1;
        fTextSizeMeasure = realTextSize;
        fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
    }

    // DirectWrite2 allows for grayscale hinting.
    fAntiAliasMode = DWRITE_TEXT_ANTIALIAS_MODE_CLEARTYPE;
    if (typeface->fFactory2 && typeface->fDWriteFontFace2 &&
        SkMask::kA8_Format == fRec.fMaskFormat &&
        !(fRec.fFlags & SkScalerContext::kGenA8FromLCD_Flag))
    {
        // DWRITE_TEXTURE_ALIASED_1x1 is now misnamed, it must also be used with grayscale.
        fTextureType = DWRITE_TEXTURE_ALIASED_1x1;
        fAntiAliasMode = DWRITE_TEXT_ANTIALIAS_MODE_GRAYSCALE;
    }

    // DirectWrite2 allows hinting to be disabled.
    fGridFitMode = DWRITE_GRID_FIT_MODE_ENABLED;
    if (fRec.getHinting() == SkFontHinting::kNone) {
        fGridFitMode = DWRITE_GRID_FIT_MODE_DISABLED;
        if (fRenderingMode != DWRITE_RENDERING_MODE_ALIASED) {
            fRenderingMode = DWRITE_RENDERING_MODE_NATURAL_SYMMETRIC;
        }
    }

    if (this->isLinearMetrics()) {
        fTextSizeMeasure = realTextSize;
        fMeasuringMode = DWRITE_MEASURING_MODE_NATURAL;
    }
}

SkScalerContext_DW::~SkScalerContext_DW() {
}

unsigned SkScalerContext_DW::generateGlyphCount() {
    if (fGlyphCount < 0) {
        fGlyphCount = this->getDWriteTypeface()->fDWriteFontFace->GetGlyphCount();
    }
    return fGlyphCount;
}

bool SkScalerContext_DW::generateAdvance(SkGlyph* glyph) {
    glyph->fAdvanceX = 0;
    glyph->fAdvanceY = 0;

    uint16_t glyphId = glyph->getGlyphID();
    DWRITE_GLYPH_METRICS gm;

    if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
        DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
    {
        MaybeExclusive l(this);
        HRBM(this->getDWriteTypeface()->fDWriteFontFace->GetGdiCompatibleGlyphMetrics(
                 fTextSizeMeasure,
                 1.0f, // pixelsPerDip
                 // This parameter does not act like the lpmat2 parameter to GetGlyphOutlineW.
                 // If it did then GsA here and G_inv below to mapVectors.
                 nullptr,
                 DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode,
                 &glyphId, 1,
                 &gm),
             "Could not get gdi compatible glyph metrics.");
    } else {
        MaybeExclusive l(this);
        HRBM(this->getDWriteTypeface()->fDWriteFontFace->GetDesignGlyphMetrics(&glyphId, 1, &gm),
             "Could not get design metrics.");
    }

    DWRITE_FONT_METRICS dwfm;
    {
        MaybeShared l(this);
        this->getDWriteTypeface()->fDWriteFontFace->GetMetrics(&dwfm);
    }
    SkScalar advanceX = fTextSizeMeasure * gm.advanceWidth / dwfm.designUnitsPerEm;

    SkVector advance = { advanceX, 0 };
    if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
        DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
    {
        // DirectWrite produced 'compatible' metrics, but while close,
        // the end result is not always an integer as it would be with GDI.
        advance.fX = SkScalarRoundToScalar(advance.fX);
    }
    fSkXform.mapVectors(&advance, 1);

    glyph->fAdvanceX = SkScalarToFloat(advance.fX);
    glyph->fAdvanceY = SkScalarToFloat(advance.fY);
    return true;
}

HRESULT SkScalerContext_DW::getBoundingBox(SkGlyph* glyph,
                                           DWRITE_RENDERING_MODE renderingMode,
                                           DWRITE_TEXTURE_TYPE textureType,
                                           RECT* bbox)
{
    //Measure raster size.
    fXform.dx = SkFixedToFloat(glyph->getSubXFixed());
    fXform.dy = SkFixedToFloat(glyph->getSubYFixed());

    FLOAT advance = 0;

    UINT16 glyphId = glyph->getGlyphID();

    DWRITE_GLYPH_OFFSET offset;
    offset.advanceOffset = 0.0f;
    offset.ascenderOffset = 0.0f;

    DWRITE_GLYPH_RUN run;
    run.glyphCount = 1;
    run.glyphAdvances = &advance;
    run.fontFace = this->getDWriteTypeface()->fDWriteFontFace.get();
    run.fontEmSize = SkScalarToFloat(fTextSizeRender);
    run.bidiLevel = 0;
    run.glyphIndices = &glyphId;
    run.isSideways = FALSE;
    run.glyphOffsets = &offset;

    SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
    {
        MaybeExclusive l(this);
        // IDWriteFactory2::CreateGlyphRunAnalysis is very bad at aliased glyphs.
        if (this->getDWriteTypeface()->fFactory2 &&
                (fGridFitMode == DWRITE_GRID_FIT_MODE_DISABLED ||
                 fAntiAliasMode == DWRITE_TEXT_ANTIALIAS_MODE_GRAYSCALE))
        {
            HRM(this->getDWriteTypeface()->fFactory2->CreateGlyphRunAnalysis(
                    &run,
                    &fXform,
                    renderingMode,
                    fMeasuringMode,
                    fGridFitMode,
                    fAntiAliasMode,
                    0.0f, // baselineOriginX,
                    0.0f, // baselineOriginY,
                    &glyphRunAnalysis),
                "Could not create DW2 glyph run analysis.");
        } else {
            HRM(this->getDWriteTypeface()->fFactory->CreateGlyphRunAnalysis(&run,
                    1.0f, // pixelsPerDip,
                    &fXform,
                    renderingMode,
                    fMeasuringMode,
                    0.0f, // baselineOriginX,
                    0.0f, // baselineOriginY,
                    &glyphRunAnalysis),
                "Could not create glyph run analysis.");
        }
    }
    {
        MaybeShared l(this);
        HRM(glyphRunAnalysis->GetAlphaTextureBounds(textureType, bbox),
            "Could not get texture bounds.");
    }
    return S_OK;
}

bool SkScalerContext_DW::isColorGlyph(const SkGlyph& glyph) {
    SkTScopedComPtr<IDWriteColorGlyphRunEnumerator> colorLayer;
    return getColorGlyphRun(glyph, &colorLayer);
}

bool SkScalerContext_DW::isPngGlyph(const SkGlyph& glyph) {
    if (!this->getDWriteTypeface()->fDWriteFontFace4) {
        return false;
    }

    DWRITE_GLYPH_IMAGE_FORMATS f;
    IDWriteFontFace4* fontFace4 = this->getDWriteTypeface()->fDWriteFontFace4.get();
    HRBM(fontFace4->GetGlyphImageFormats(glyph.getGlyphID(), 0, UINT32_MAX, &f),
         "Cannot get glyph image formats.");
    return f & DWRITE_GLYPH_IMAGE_FORMATS_PNG;
}

bool SkScalerContext_DW::getColorGlyphRun(const SkGlyph& glyph,
                                          IDWriteColorGlyphRunEnumerator** colorGlyph)
{
    FLOAT advance = 0;
    UINT16 glyphId = glyph.getGlyphID();

    DWRITE_GLYPH_OFFSET offset;
    offset.advanceOffset = 0.0f;
    offset.ascenderOffset = 0.0f;

    DWRITE_GLYPH_RUN run;
    run.glyphCount = 1;
    run.glyphAdvances = &advance;
    run.fontFace = this->getDWriteTypeface()->fDWriteFontFace.get();
    run.fontEmSize = SkScalarToFloat(fTextSizeRender);
    run.bidiLevel = 0;
    run.glyphIndices = &glyphId;
    run.isSideways = FALSE;
    run.glyphOffsets = &offset;

    HRESULT hr = this->getDWriteTypeface()->fFactory2->TranslateColorGlyphRun(
        0, 0, &run, nullptr, fMeasuringMode, &fXform, 0, colorGlyph);
    if (hr == DWRITE_E_NOCOLOR) {
        return false;
    }
    HRBM(hr, "Failed to translate color glyph run");
    return true;
}

void SkScalerContext_DW::generateColorMetrics(SkGlyph* glyph) {
    SkTScopedComPtr<IDWriteColorGlyphRunEnumerator> colorLayers;
    HRVM(getColorGlyphRun(*glyph, &colorLayers), "Could not get color glyph run");
    SkASSERT(colorLayers.get());

    SkRect bounds = SkRect::MakeEmpty();
    BOOL hasNextRun = FALSE;
    while (SUCCEEDED(colorLayers->MoveNext(&hasNextRun)) && hasNextRun) {
        const DWRITE_COLOR_GLYPH_RUN* colorGlyph;
        HRVM(colorLayers->GetCurrentRun(&colorGlyph), "Could not get current color glyph run");

        SkPath path;
        SkTScopedComPtr<IDWriteGeometrySink> geometryToPath;
        HRVM(SkDWriteGeometrySink::Create(&path, &geometryToPath),
            "Could not create geometry to path converter.");
        {
            MaybeExclusive l(this);
            HRVM(colorGlyph->glyphRun.fontFace->GetGlyphRunOutline(
                    colorGlyph->glyphRun.fontEmSize,
                    colorGlyph->glyphRun.glyphIndices,
                    colorGlyph->glyphRun.glyphAdvances,
                    colorGlyph->glyphRun.glyphOffsets,
                    colorGlyph->glyphRun.glyphCount,
                    colorGlyph->glyphRun.isSideways,
                    colorGlyph->glyphRun.bidiLevel % 2, //rtl
                    geometryToPath.get()),
                "Could not create glyph outline.");
        }
        bounds.join(path.getBounds());
    }
    SkMatrix matrix = fSkXform;
    if (this->isSubpixel()) {
        matrix.postTranslate(SkFixedToScalar(glyph->getSubXFixed()),
                             SkFixedToScalar(glyph->getSubYFixed()));
    }
    matrix.mapRect(&bounds);
    // Round float bound values into integer.
    SkIRect ibounds = bounds.roundOut();

    glyph->fWidth = ibounds.fRight - ibounds.fLeft;
    glyph->fHeight = ibounds.fBottom - ibounds.fTop;
    glyph->fLeft = ibounds.fLeft;
    glyph->fTop = ibounds.fTop;
}

#ifdef USE_PNG
namespace {
struct Context {
    SkTScopedComPtr<IDWriteFontFace4> fontFace4;
    void* glyphDataContext;
    Context(IDWriteFontFace4* face4, void* context)
        : fontFace4(SkRefComPtr(face4))
        , glyphDataContext(context)
    {}
};

static void ReleaseProc(const void* ptr, void* context) {
    Context* ctx = (Context*)context;
    ctx->fontFace4->ReleaseGlyphImageData(ctx->glyphDataContext);
    delete ctx;
}
}

void SkScalerContext_DW::generatePngMetrics(SkGlyph* glyph) {
    SkASSERT(isPngGlyph(*glyph));
    SkASSERT(glyph->fMaskFormat == SkMask::Format::kARGB32_Format);
    SkASSERT(this->getDWriteTypeface()->fDWriteFontFace4);

    IDWriteFontFace4* fontFace4 = this->getDWriteTypeface()->fDWriteFontFace4.get();
    DWRITE_GLYPH_IMAGE_DATA glyphData;
    void* glyphDataContext;
    HRVM(fontFace4->GetGlyphImageData(glyph->getGlyphID(),
                                      fTextSizeRender,
                                      DWRITE_GLYPH_IMAGE_FORMATS_PNG,
                                      &glyphData,
                                      &glyphDataContext),
         "Glyph image data could not be acquired.");

    Context* context = new Context(fontFace4, glyphDataContext);
    sk_sp<SkData> data = SkData::MakeWithProc(glyphData.imageData,
                                              glyphData.imageDataSize,
                                              &ReleaseProc,
                                              context);

    std::unique_ptr<SkCodec> codec = SkCodec::MakeFromData(std::move(data));
    if (!codec) {
        return;
    }

    SkImageInfo info = codec->getInfo();
    SkRect bounds = SkRect::MakeLTRB(SkIntToScalar(info.bounds().fLeft),
                                     SkIntToScalar(info.bounds().fTop),
                                     SkIntToScalar(info.bounds().fRight),
                                     SkIntToScalar(info.bounds().fBottom));

    SkMatrix matrix = fSkXform;
    SkScalar scale = fTextSizeRender / glyphData.pixelsPerEm;
    matrix.preScale(scale, scale);
    matrix.preTranslate(-glyphData.horizontalLeftOrigin.x, -glyphData.horizontalLeftOrigin.y);
    if (this->isSubpixel()) {
        matrix.postTranslate(SkFixedToScalar(glyph->getSubXFixed()),
                             SkFixedToScalar(glyph->getSubYFixed()));
    }
    matrix.mapRect(&bounds);
    bounds.roundOut();

    glyph->fWidth = bounds.width();
    glyph->fHeight = bounds.height();
    glyph->fLeft = bounds.left();
    glyph->fTop = bounds.top();
    return;
}
#endif

void SkScalerContext_DW::generateMetrics(SkGlyph* glyph) {


     // GetAlphaTextureBounds succeeds but sometimes returns empty bounds like
     // { 0x80000000, 0x80000000, 0x80000000, 0x80000000 }
     // for small, but not quite zero, sized glyphs.
     // Only set as non-empty if the returned bounds are non-empty.
    auto glyphCheckAndSetBounds = [](SkGlyph* glyph, const RECT& bbox) {
        if (bbox.left >= bbox.right || bbox.top >= bbox.bottom) {
            return false;
        }

        // We're trying to pack left and top into int16_t,
        // and width and height into uint16_t, after outsetting by 1.
        if (!SkIRect::MakeXYWH(-32767, -32767, 65535, 65535).contains(
                    SkIRect::MakeLTRB(bbox.left, bbox.top, bbox.right, bbox.bottom))) {
            return false;
        }

        glyph->fWidth = SkToU16(bbox.right - bbox.left);
        glyph->fHeight = SkToU16(bbox.bottom - bbox.top);
        glyph->fLeft = SkToS16(bbox.left);
        glyph->fTop = SkToS16(bbox.top);
        return true;
    };

    glyph->fWidth = 0;
    glyph->fHeight = 0;
    glyph->fLeft = 0;
    glyph->fTop = 0;
    glyph->fMaskFormat = fRec.fMaskFormat;

    if (!this->generateAdvance(glyph)) {
        return;
    }

    if (fIsColorFont && isColorGlyph(*glyph)) {
        glyph->fMaskFormat = SkMask::kARGB32_Format;
        generateColorMetrics(glyph);
        return;
    }

    if (fIsColorFont && isPngGlyph(*glyph)) {
#ifdef USE_PNG
        glyph->fMaskFormat = SkMask::kARGB32_Format;
        generatePngMetrics(glyph);
#endif
        return;
    }

    RECT bbox;
    HRVM(this->getBoundingBox(glyph, fRenderingMode, fTextureType, &bbox),
         "Requested bounding box could not be determined.");

    if (glyphCheckAndSetBounds(glyph, bbox)) {
        return;
    }

    // GetAlphaTextureBounds succeeds but returns an empty RECT if there are no
    // glyphs of the specified texture type or it is too big for smoothing.
    // When this happens, try with the alternate texture type.
    if (DWRITE_TEXTURE_ALIASED_1x1 != fTextureType ||
        DWRITE_TEXT_ANTIALIAS_MODE_GRAYSCALE == fAntiAliasMode)
    {
        HRVM(this->getBoundingBox(glyph,
                                  DWRITE_RENDERING_MODE_ALIASED,
                                  DWRITE_TEXTURE_ALIASED_1x1,
                                  &bbox),
             "Fallback bounding box could not be determined.");
        if (glyphCheckAndSetBounds(glyph, bbox)) {
            glyph->fForceBW = 1;
            glyph->fMaskFormat = SkMask::kBW_Format;
        }
    }
    // TODO: handle the case where a request for DWRITE_TEXTURE_ALIASED_1x1
    // fails, and try DWRITE_TEXTURE_CLEARTYPE_3x1.
}

void SkScalerContext_DW::generateFontMetrics(SkFontMetrics* metrics) {
    if (nullptr == metrics) {
        return;
    }

    sk_bzero(metrics, sizeof(*metrics));

    DWRITE_FONT_METRICS dwfm;
    if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
        DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
    {
        this->getDWriteTypeface()->fDWriteFontFace->GetGdiCompatibleMetrics(
             fTextSizeRender,
             1.0f, // pixelsPerDip
             &fXform,
             &dwfm);
    } else {
        this->getDWriteTypeface()->fDWriteFontFace->GetMetrics(&dwfm);
    }

    SkScalar upem = SkIntToScalar(dwfm.designUnitsPerEm);

    metrics->fAscent = -fTextSizeRender * SkIntToScalar(dwfm.ascent) / upem;
    metrics->fDescent = fTextSizeRender * SkIntToScalar(dwfm.descent) / upem;
    metrics->fLeading = fTextSizeRender * SkIntToScalar(dwfm.lineGap) / upem;
    metrics->fXHeight = fTextSizeRender * SkIntToScalar(dwfm.xHeight) / upem;
    metrics->fCapHeight = fTextSizeRender * SkIntToScalar(dwfm.capHeight) / upem;
    metrics->fUnderlineThickness = fTextSizeRender * SkIntToScalar(dwfm.underlineThickness) / upem;
    metrics->fUnderlinePosition = -(fTextSizeRender * SkIntToScalar(dwfm.underlinePosition) / upem);
    metrics->fStrikeoutThickness = fTextSizeRender * SkIntToScalar(dwfm.strikethroughThickness) / upem;
    metrics->fStrikeoutPosition = -(fTextSizeRender * SkIntToScalar(dwfm.strikethroughPosition) / upem);

    metrics->fFlags |= SkFontMetrics::kUnderlineThicknessIsValid_Flag;
    metrics->fFlags |= SkFontMetrics::kUnderlinePositionIsValid_Flag;
    metrics->fFlags |= SkFontMetrics::kStrikeoutThicknessIsValid_Flag;
    metrics->fFlags |= SkFontMetrics::kStrikeoutPositionIsValid_Flag;

    if (this->getDWriteTypeface()->fDWriteFontFace1.get()) {
        DWRITE_FONT_METRICS1 dwfm1;
        this->getDWriteTypeface()->fDWriteFontFace1->GetMetrics(&dwfm1);
        metrics->fTop = -fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxTop) / upem;
        metrics->fBottom = -fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxBottom) / upem;
        metrics->fXMin = fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxLeft) / upem;
        metrics->fXMax = fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxRight) / upem;

        metrics->fMaxCharWidth = metrics->fXMax - metrics->fXMin;
        return;
    }

    AutoTDWriteTable<SkOTTableHead> head(this->getDWriteTypeface()->fDWriteFontFace.get());
    if (head.fExists &&
        head.fSize >= sizeof(SkOTTableHead) &&
        head->version == SkOTTableHead::version1)
    {
        metrics->fTop = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMax) / upem;
        metrics->fBottom = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMin) / upem;
        metrics->fXMin = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMin) / upem;
        metrics->fXMax = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMax) / upem;

        metrics->fMaxCharWidth = metrics->fXMax - metrics->fXMin;
        return;
    }

    metrics->fTop = metrics->fAscent;
    metrics->fBottom = metrics->fDescent;
}

///////////////////////////////////////////////////////////////////////////////

#include "include/private/SkColorData.h"

void SkScalerContext_DW::BilevelToBW(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph) {
    const int width = glyph.width();
    const size_t dstRB = (width + 7) >> 3;
    uint8_t* SK_RESTRICT dst = static_cast<uint8_t*>(glyph.fImage);

    int byteCount = width >> 3;
    int bitCount = width & 7;

    for (int y = 0; y < glyph.height(); ++y) {
        if (byteCount > 0) {
            for (int i = 0; i < byteCount; ++i) {
                unsigned byte = 0;
                byte |= src[0] & (1 << 7);
                byte |= src[1] & (1 << 6);
                byte |= src[2] & (1 << 5);
                byte |= src[3] & (1 << 4);
                byte |= src[4] & (1 << 3);
                byte |= src[5] & (1 << 2);
                byte |= src[6] & (1 << 1);
                byte |= src[7] & (1 << 0);
                dst[i] = byte;
                src += 8;
            }
        }
        if (bitCount > 0) {
            unsigned byte = 0;
            unsigned mask = 0x80;
            for (int i = 0; i < bitCount; i++) {
                byte |= (src[i]) & mask;
                mask >>= 1;
            }
            dst[byteCount] = byte;
        }
        src += bitCount;
        dst += dstRB;
    }
}

template<bool APPLY_PREBLEND>
void SkScalerContext_DW::GrayscaleToA8(const uint8_t* SK_RESTRICT src,
                                       const SkGlyph& glyph,
                                       const uint8_t* table8) {
    const size_t dstRB = glyph.rowBytes();
    const int width = glyph.width();
    uint8_t* SK_RESTRICT dst = static_cast<uint8_t*>(glyph.fImage);

    for (int y = 0; y < glyph.height(); y++) {
        for (int i = 0; i < width; i++) {
            U8CPU a = *(src++);
            dst[i] = sk_apply_lut_if<APPLY_PREBLEND>(a, table8);
        }
        dst = SkTAddOffset<uint8_t>(dst, dstRB);
    }
}

template<bool APPLY_PREBLEND>
void SkScalerContext_DW::RGBToA8(const uint8_t* SK_RESTRICT src,
                                 const SkGlyph& glyph,
                                 const uint8_t* table8) {
    const size_t dstRB = glyph.rowBytes();
    const int width = glyph.width();
    uint8_t* SK_RESTRICT dst = static_cast<uint8_t*>(glyph.fImage);

    for (int y = 0; y < glyph.height(); y++) {
        for (int i = 0; i < width; i++) {
            U8CPU g = src[1];
            src += 3;

            // Ignore the R, B channels. It looks the closest to what
            // D2D with grayscale AA has. But there's no way
            // to just get a grayscale AA alpha texture from a glyph run.
            dst[i] = sk_apply_lut_if<APPLY_PREBLEND>(g, table8);
        }
        dst = SkTAddOffset<uint8_t>(dst, dstRB);
    }
}

template<bool APPLY_PREBLEND, bool RGB>
void SkScalerContext_DW::RGBToLcd16(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph,
                                    const uint8_t* tableR, const uint8_t* tableG,
                                    const uint8_t* tableB, int clearTypeLevel) {
    const size_t dstRB = glyph.rowBytes();
    const int width = glyph.width();
    uint16_t* SK_RESTRICT dst = static_cast<uint16_t*>(glyph.fImage);

    for (int y = 0; y < glyph.height(); y++) {
        for (int i = 0; i < width; i++) {
            int r, g, b;
            if (RGB) {
                r = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableR);
                g = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableG);
                b = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableB);
            } else {
                b = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableB);
                g = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableG);
                r = sk_apply_lut_if<APPLY_PREBLEND>(*(src++), tableR);
            }
            r = g + (((r - g) * clearTypeLevel) >> 8);
            b = g + (((b - g) * clearTypeLevel) >> 8);
            dst[i] = SkPack888ToRGB16(r, g, b);
        }
        dst = SkTAddOffset<uint16_t>(dst, dstRB);
    }
}

const void* SkScalerContext_DW::drawDWMask(const SkGlyph& glyph,
                                           DWRITE_RENDERING_MODE renderingMode,
                                           DWRITE_TEXTURE_TYPE textureType)
{
    int sizeNeeded = glyph.width() * glyph.height();
    if (DWRITE_TEXTURE_CLEARTYPE_3x1 == textureType) {
        sizeNeeded *= 3;
    }
    if (sizeNeeded > fBits.count()) {
        fBits.setCount(sizeNeeded);
    }

    // erase
    memset(fBits.begin(), 0, sizeNeeded);

    fXform.dx = SkFixedToFloat(glyph.getSubXFixed());
    fXform.dy = SkFixedToFloat(glyph.getSubYFixed());

    FLOAT advance = 0.0f;

    UINT16 index = glyph.getGlyphID();

    DWRITE_GLYPH_OFFSET offset;
    offset.advanceOffset = 0.0f;
    offset.ascenderOffset = 0.0f;

    DWRITE_GLYPH_RUN run;
    run.glyphCount = 1;
    run.glyphAdvances = &advance;
    run.fontFace = this->getDWriteTypeface()->fDWriteFontFace.get();
    run.fontEmSize = SkScalarToFloat(fTextSizeRender);
    run.bidiLevel = 0;
    run.glyphIndices = &index;
    run.isSideways = FALSE;
    run.glyphOffsets = &offset;
    {
        SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
        {
            MaybeExclusive l(this);
            // IDWriteFactory2::CreateGlyphRunAnalysis is very bad at aliased glyphs.
            if (this->getDWriteTypeface()->fFactory2 &&
                    (fGridFitMode == DWRITE_GRID_FIT_MODE_DISABLED ||
                     fAntiAliasMode == DWRITE_TEXT_ANTIALIAS_MODE_GRAYSCALE))
            {
                HRNM(this->getDWriteTypeface()->fFactory2->CreateGlyphRunAnalysis(&run,
                         &fXform,
                         renderingMode,
                         fMeasuringMode,
                         fGridFitMode,
                         fAntiAliasMode,
                         0.0f, // baselineOriginX,
                         0.0f, // baselineOriginY,
                         &glyphRunAnalysis),
                     "Could not create DW2 glyph run analysis.");
            } else {
                HRNM(this->getDWriteTypeface()->fFactory->CreateGlyphRunAnalysis(&run,
                         1.0f, // pixelsPerDip,
                         &fXform,
                         renderingMode,
                         fMeasuringMode,
                         0.0f, // baselineOriginX,
                         0.0f, // baselineOriginY,
                         &glyphRunAnalysis),
                     "Could not create glyph run analysis.");
            }
        }
        //NOTE: this assumes that the glyph has already been measured
        //with an exact same glyph run analysis.
        RECT bbox;
        bbox.left = glyph.left();
        bbox.top = glyph.top();
        bbox.right = glyph.left() + glyph.width();
        bbox.bottom = glyph.top() + glyph.height();
        {
            MaybeShared l(this);
            HRNM(glyphRunAnalysis->CreateAlphaTexture(textureType,
                    &bbox,
                    fBits.begin(),
                    sizeNeeded),
                "Could not draw mask.");
        }
    }
    return fBits.begin();
}

void SkScalerContext_DW::generateColorGlyphImage(const SkGlyph& glyph) {
    SkASSERT(isColorGlyph(glyph));
    SkASSERT(glyph.fMaskFormat == SkMask::Format::kARGB32_Format);

    memset(glyph.fImage, 0, glyph.imageSize());

    SkTScopedComPtr<IDWriteColorGlyphRunEnumerator> colorLayers;
    getColorGlyphRun(glyph, &colorLayers);
    SkASSERT(colorLayers.get());

    SkMatrix matrix = fSkXform;
    matrix.postTranslate(-SkIntToScalar(glyph.left()), -SkIntToScalar(glyph.top()));
    if (this->isSubpixel()) {
        matrix.postTranslate(SkFixedToScalar(glyph.getSubXFixed()),
                             SkFixedToScalar(glyph.getSubYFixed()));
    }
    SkRasterClip rc(SkIRect::MakeWH(glyph.width(), glyph.height()));
    SkDraw draw;
    draw.fDst = SkPixmap(SkImageInfo::MakeN32(glyph.width(), glyph.height(), kPremul_SkAlphaType),
                         glyph.fImage,
                         glyph.rowBytesUsingFormat(SkMask::Format::kARGB32_Format));
    draw.fMatrix = &matrix;
    draw.fRC = &rc;

    SkPaint paint;
    paint.setAntiAlias(fRenderingMode != DWRITE_RENDERING_MODE_ALIASED);

    BOOL hasNextRun = FALSE;
    while (SUCCEEDED(colorLayers->MoveNext(&hasNextRun)) && hasNextRun) {
        const DWRITE_COLOR_GLYPH_RUN* colorGlyph;
        HRVM(colorLayers->GetCurrentRun(&colorGlyph), "Could not get current color glyph run");

        SkColor color;
        if (colorGlyph->paletteIndex != 0xffff) {
            color = SkColorSetARGB(sk_float_round2int(colorGlyph->runColor.a * 255),
                                   sk_float_round2int(colorGlyph->runColor.r * 255),
                                   sk_float_round2int(colorGlyph->runColor.g * 255),
                                   sk_float_round2int(colorGlyph->runColor.b * 255));
        } else {
            // If all components of runColor are 0 or (equivalently) paletteIndex is 0xFFFF then
            // the 'current brush' is used. fRec.getLuminanceColor() is kinda sorta what is wanted
            // here, but not really, it will often be the wrong value because it wan't designed for
            // this.
            // TODO: implement this fully, bug.skia.org/5788
            color = fRec.getLuminanceColor();
        }
        paint.setColor(color);

        SkPath path;
        SkTScopedComPtr<IDWriteGeometrySink> geometryToPath;
        HRVM(SkDWriteGeometrySink::Create(&path, &geometryToPath),
             "Could not create geometry to path converter.");
        {
            MaybeExclusive l(this);
            HRVM(colorGlyph->glyphRun.fontFace->GetGlyphRunOutline(
                colorGlyph->glyphRun.fontEmSize,
                colorGlyph->glyphRun.glyphIndices,
                colorGlyph->glyphRun.glyphAdvances,
                colorGlyph->glyphRun.glyphOffsets,
                colorGlyph->glyphRun.glyphCount,
                colorGlyph->glyphRun.isSideways,
                colorGlyph->glyphRun.bidiLevel % 2, //rtl
                geometryToPath.get()),
                "Could not create glyph outline.");
        }
        draw.drawPath(path, paint, nullptr, true /* pathIsMutable */);
    }
}

#ifdef USE_PNG
void SkScalerContext_DW::generatePngGlyphImage(const SkGlyph& glyph) {
    SkASSERT(isPngGlyph(glyph));
    SkASSERT(glyph.fMaskFormat == SkMask::Format::kARGB32_Format);
    SkASSERT(this->getDWriteTypeface()->fDWriteFontFace4);

    IDWriteFontFace4* fontFace4 = this->getDWriteTypeface()->fDWriteFontFace4.get();
    DWRITE_GLYPH_IMAGE_DATA glyphData;
    void* glyphDataContext;
    HRVM(fontFace4->GetGlyphImageData(glyph.getGlyphID(),
                                      fTextSizeRender,
                                      DWRITE_GLYPH_IMAGE_FORMATS_PNG,
                                      &glyphData,
                                      &glyphDataContext),
         "Glyph image data could not be acquired.");
    Context* context = new Context(fontFace4, glyphDataContext);
    sk_sp<SkData> data = SkData::MakeWithProc(glyphData.imageData,
                                              glyphData.imageDataSize,
                                              &ReleaseProc,
                                              context);
    sk_sp<SkImage> image = SkImage::MakeFromEncoded(std::move(data));

    SkBitmap dstBitmap;
    dstBitmap.setInfo(SkImageInfo::Make(glyph.width(), glyph.height(),
                                        kN32_SkColorType,
                                        kPremul_SkAlphaType),
                      glyph.rowBytes());
    dstBitmap.setPixels(glyph.fImage);

    SkCanvas canvas(dstBitmap);
    canvas.clear(SK_ColorTRANSPARENT);
    canvas.translate(-glyph.left(), -glyph.top());
    if (this->isSubpixel()) {
        canvas.translate(SkFixedToScalar(glyph.getSubXFixed()),
                         SkFixedToScalar(glyph.getSubYFixed()));
    }
    canvas.concat(fSkXform);
    SkScalar ratio = fTextSizeRender / glyphData.pixelsPerEm;
    canvas.scale(ratio, ratio);
    canvas.translate(-glyphData.horizontalLeftOrigin.x, -glyphData.horizontalLeftOrigin.y);
    canvas.drawImage(image, 0, 0, nullptr);
}
#endif

void SkScalerContext_DW::generateImage(const SkGlyph& glyph) {
    //Create the mask.
    DWRITE_RENDERING_MODE renderingMode = fRenderingMode;
    DWRITE_TEXTURE_TYPE textureType = fTextureType;
    if (glyph.fForceBW) {
        renderingMode = DWRITE_RENDERING_MODE_ALIASED;
        textureType = DWRITE_TEXTURE_ALIASED_1x1;
    }

    if (SkMask::kARGB32_Format == glyph.fMaskFormat) {
        if (fIsColorFont) {
            if (isColorGlyph(glyph)) {
                generateColorGlyphImage(glyph);
                return;
#ifdef USE_PNG
            } else if (isPngGlyph(glyph)) {
                generatePngGlyphImage(glyph);
                return;
#endif
            }
        }
        SkDEBUGFAIL("Could not generate image from the given color font format.");
        return;
    }

    const void* bits = this->drawDWMask(glyph, renderingMode, textureType);
    if (!bits) {
        sk_bzero(glyph.fImage, glyph.imageSize());
        return;
    }

    //Copy the mask into the glyph.
    const uint8_t* src = (const uint8_t*)bits;
    if (DWRITE_RENDERING_MODE_ALIASED == renderingMode) {
        SkASSERT(SkMask::kBW_Format == glyph.fMaskFormat);
        SkASSERT(DWRITE_TEXTURE_ALIASED_1x1 == textureType);
        BilevelToBW(src, glyph);
    } else if (!isLCD(fRec)) {
        if (textureType == DWRITE_TEXTURE_ALIASED_1x1) {
            if (fPreBlend.isApplicable()) {
                GrayscaleToA8<true>(src, glyph, fPreBlend.fG);
            } else {
                GrayscaleToA8<false>(src, glyph, fPreBlend.fG);
            }
        } else {
            if (fPreBlend.isApplicable()) {
                RGBToA8<true>(src, glyph, fPreBlend.fG);
            } else {
                RGBToA8<false>(src, glyph, fPreBlend.fG);
            }
        }
    } else {
        SkASSERT(SkMask::kLCD16_Format == glyph.fMaskFormat);
        if (fPreBlend.isApplicable()) {
            if (fRec.fFlags & SkScalerContext::kLCD_BGROrder_Flag) {
                RGBToLcd16<true, false>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB, fClearTypeLevel);
            } else {
                RGBToLcd16<true, true>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB, fClearTypeLevel);
            }
        } else {
            if (fRec.fFlags & SkScalerContext::kLCD_BGROrder_Flag) {
                RGBToLcd16<false, false>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB, fClearTypeLevel);
            } else {
                RGBToLcd16<false, true>(src, glyph, fPreBlend.fR, fPreBlend.fG, fPreBlend.fB, fClearTypeLevel);
            }
        }
    }
}

bool SkScalerContext_DW::generatePath(SkGlyphID glyph, SkPath* path) {
    SkASSERT(path);

    path->reset();

    SkTScopedComPtr<IDWriteGeometrySink> geometryToPath;
    HRBM(SkDWriteGeometrySink::Create(path, &geometryToPath),
         "Could not create geometry to path converter.");
    UINT16 glyphId = SkTo<UINT16>(glyph);
    {
        MaybeExclusive l(this);
        //TODO: convert to<->from DIUs? This would make a difference if hinting.
        //It may not be needed, it appears that DirectWrite only hints at em size.
        HRBM(this->getDWriteTypeface()->fDWriteFontFace->GetGlyphRunOutline(
             SkScalarToFloat(fTextSizeRender),
             &glyphId,
             nullptr, //advances
             nullptr, //offsets
             1, //num glyphs
             FALSE, //sideways
             FALSE, //rtl
             geometryToPath.get()),
             "Could not create glyph outline.");
    }

    path->transform(fSkXform);
    return true;
}

#endif//defined(SK_BUILD_FOR_WIN)