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 (5216dd412535)

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
/* vim: set sw=4 sts=4 et cin: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is OS/2 code in Thebes.
 *
 * The Initial Developer of the Original Code is
 * Peter Weilbacher <mozilla@Weilbacher.org>.
 * Portions created by the Initial Developer are Copyright (C) 2006-2007
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   authors of code taken from gfxPangoFonts:
 *     Mozilla Foundation
 *     Vladimir Vukicevic <vladimir@mozilla.com>
 *     Masayuki Nakano <masayuki@d-toybox.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "gfxContext.h"

#include "gfxOS2Platform.h"
#include "gfxOS2Surface.h"
#include "gfxOS2Fonts.h"
#include "nsTArray.h"
#include "gfxAtoms.h"

#include "nsIServiceManager.h"
#include "nsIPlatformCharset.h"
#include "nsIPrefBranch.h"
#include "nsIPrefService.h"

/**********************************************************************
 * class gfxOS2Font
 **********************************************************************/

gfxOS2Font::gfxOS2Font(gfxOS2FontEntry *aFontEntry, const gfxFontStyle *aFontStyle)
    : gfxFont(aFontEntry, aFontStyle),
      mFontFace(nsnull), mScaledFont(nsnull),
      mMetrics(nsnull), mAdjustedSize(0),
      mHinting(FC_HINT_MEDIUM), mAntialias(FcTrue)
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2Font[%p]::gfxOS2Font(%p \"%s\", aFontStyle)\n",
           (void *)this, (void *)aFontEntry,
           NS_LossyConvertUTF16toASCII(aFontEntry->Name()).get());
#endif
    // try to get the preferences for hinting, antialias, and embolden options
    nsCOMPtr<nsIPrefBranch> prefbranch = do_GetService(NS_PREFSERVICE_CONTRACTID);
    if (prefbranch) {
        int value;
        nsresult rv = prefbranch->GetIntPref("gfx.os2.font.hinting", &value);
        if (NS_SUCCEEDED(rv) && value >= FC_HINT_NONE && value <= FC_HINT_FULL)
            mHinting = value;

        PRBool enabled;
        rv = prefbranch->GetBoolPref("gfx.os2.font.antialiasing", &enabled);
        if (NS_SUCCEEDED(rv))
            mAntialias = enabled;
    }
#ifdef DEBUG_thebes_2
    printf("  font display options: hinting=%d, antialiasing=%s\n",
           mHinting, mAntialias ? "on" : "off");
#endif
}

gfxOS2Font::~gfxOS2Font()
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2Font[%#x]::~gfxOS2Font()\n", (unsigned)this);
#endif
    if (mFontFace) {
        cairo_font_face_destroy(mFontFace);
    }
    if (mScaledFont) {
        cairo_scaled_font_destroy(mScaledFont);
    }
    if (mMetrics) {
        delete mMetrics;
    }
    mFontFace = nsnull;
    mScaledFont = nsnull;
    mMetrics = nsnull;
}

// fill font metrics structure with default values in case of error
static void FillMetricsDefaults(gfxFont::Metrics *aMetrics)
{
    aMetrics->emAscent = 0.8 * aMetrics->emHeight;
    aMetrics->emDescent = 0.2 * aMetrics->emHeight;
    aMetrics->maxAscent = aMetrics->emAscent;
    aMetrics->maxDescent = aMetrics->maxDescent;
    aMetrics->maxHeight = aMetrics->emHeight;
    aMetrics->internalLeading = 0.0;
    aMetrics->externalLeading = 0.2 * aMetrics->emHeight;
    aMetrics->spaceWidth = 0.5 * aMetrics->emHeight;
    aMetrics->maxAdvance = aMetrics->spaceWidth;
    aMetrics->aveCharWidth = aMetrics->spaceWidth;
    aMetrics->zeroOrAveCharWidth = aMetrics->spaceWidth;
    aMetrics->xHeight = 0.5 * aMetrics->emHeight;
    aMetrics->underlineSize = aMetrics->emHeight / 14.0;
    aMetrics->underlineOffset = -aMetrics->underlineSize;
    aMetrics->strikeoutOffset = 0.25 * aMetrics->emHeight;
    aMetrics->strikeoutSize = aMetrics->underlineSize;
    aMetrics->superscriptOffset = aMetrics->xHeight;
    aMetrics->subscriptOffset = aMetrics->xHeight;
}

// Snap a line to pixels while keeping the center and size of the
// line as close to the original position as possible.
static void SnapLineToPixels(gfxFloat& aOffset, gfxFloat& aSize)
{
    gfxFloat snappedSize = PR_MAX(NS_floor(aSize + 0.5), 1.0);
    // Correct offset for change in size
    gfxFloat offset = aOffset - 0.5 * (aSize - snappedSize);
    // Snap offset
    aOffset = NS_floor(offset + 0.5);
    aSize = snappedSize;
}

// gfxOS2Font::GetMetrics()
// return the metrics of the current font using the gfxFont metrics structure.
// If the metrics are not available yet, compute them using the FreeType
// function on the font. (This is partly based on the respective function from
// gfxPangoFonts)
const gfxFont::Metrics& gfxOS2Font::GetMetrics()
{
#ifdef DEBUG_thebes_1
    printf("gfxOS2Font[%#x]::GetMetrics()\n", (unsigned)this);
#endif
    if (mMetrics) {
        return *mMetrics;
    }

    // whatever happens below, we can always create the metrics
    mMetrics = new gfxFont::Metrics;
    mSpaceGlyph = 0;

    // round size to integer pixels, this is to get full pixels for layout
    // together with internal/external leading (see below)
    mMetrics->emHeight = NS_floor(GetStyle()->size + 0.5);

    cairo_scaled_font_t* scaledFont = CairoScaledFont();
    if (!scaledFont) {
        FillMetricsDefaults(mMetrics);
        return *mMetrics;
    }

    FT_Face face = cairo_ft_scaled_font_lock_face(scaledFont);
    if (!face) {
        // Abort here already, otherwise we crash in the following
        // this can happen if the font-size requested is zero.
        FillMetricsDefaults(mMetrics);
        return *mMetrics;
    }
    if (!face->charmap) {
        // Also abort, if the charmap isn't loaded; then the char
        // lookups won't work. This happens for fonts without Unicode
        // charmap.
        cairo_ft_scaled_font_unlock_face(scaledFont);
        FillMetricsDefaults(mMetrics);
        return *mMetrics;
    }

    // compute font scaling factors
    gfxFloat emUnit = 1.0 * face->units_per_EM;
    gfxFloat xScale = face->size->metrics.x_ppem / emUnit;
    gfxFloat yScale = face->size->metrics.y_ppem / emUnit;

    FT_UInt gid; // glyph ID

    // properties of space
    gid = FT_Get_Char_Index(face, ' ');
    if (gid) {
        // Load glyph into glyph slot. Use load_default here to get results in
        // 26.6 fractional pixel format which is what is used for all other
        // characters in gfxOS2FontGroup::CreateGlyphRunsFT.
        FT_Load_Glyph(face, gid, FT_LOAD_DEFAULT);
        // glyph width doesn't work for spaces, use advance instead
        mMetrics->spaceWidth = face->glyph->advance.x >> 6;
        // save the space glyph
        mSpaceGlyph = gid;
    } else {
        NS_ASSERTION(gid, "this font doesn't have a space glyph!");
        mMetrics->spaceWidth = face->max_advance_width * xScale;
    }

    // properties of 'x', also use its width as average width
    gid = FT_Get_Char_Index(face, 'x'); // select the glyph
    if (gid) {
        // Load glyph into glyph slot. Here, use no_scale to get font units.
        FT_Load_Glyph(face, gid, FT_LOAD_NO_SCALE);
        mMetrics->xHeight = face->glyph->metrics.height * yScale;
        mMetrics->aveCharWidth = face->glyph->metrics.horiAdvance * xScale;
    } else {
        // this font doesn't have an 'x'...
        // fake these metrics using a fraction of the font size
        mMetrics->xHeight = mMetrics->emHeight * 0.5;
        mMetrics->aveCharWidth = mMetrics->emHeight * 0.5;
    }

    // properties of '0', for 'ch' units
    gid = FT_Get_Char_Index(face, '0');
    if (gid) {
        FT_Load_Glyph(face, gid, FT_LOAD_NO_SCALE);
        mMetrics->zeroOrAveCharWidth = face->glyph->metrics.horiAdvance * xScale;
    } else {
        // this font doesn't have a '0'
        mMetrics->zeroOrAveCharWidth = mMetrics->aveCharWidth;
    }

    // compute an adjusted size if we need to
    if (mAdjustedSize == 0 && GetStyle()->sizeAdjust != 0) {
        gfxFloat aspect = mMetrics->xHeight / GetStyle()->size;
        mAdjustedSize = GetStyle()->GetAdjustedSize(aspect);
        mMetrics->emHeight = mAdjustedSize;
    }

    // now load the OS/2 TrueType table to access some more properties
    TT_OS2 *os2 = (TT_OS2 *)FT_Get_Sfnt_Table(face, ft_sfnt_os2);
    if (os2 && os2->version != 0xFFFF) { // should be there if not old Mac font
        // if we are here we can improve the avgCharWidth
        mMetrics->aveCharWidth = PR_MAX(mMetrics->aveCharWidth,
                                        os2->xAvgCharWidth * xScale);

        mMetrics->superscriptOffset = PR_MAX(os2->ySuperscriptYOffset * yScale, 1.0);
        // some fonts have the incorrect sign (from gfxPangoFonts)
        mMetrics->subscriptOffset   = PR_MAX(fabs(os2->ySubscriptYOffset * yScale),
                                             1.0);
        mMetrics->strikeoutOffset   = os2->yStrikeoutPosition * yScale;
        mMetrics->strikeoutSize     = os2->yStrikeoutSize * yScale;
    } else {
        // use fractions of emHeight instead of xHeight for these to be more robust
        mMetrics->superscriptOffset = mMetrics->emHeight * 0.5;
        mMetrics->subscriptOffset   = mMetrics->emHeight * 0.2;
        mMetrics->strikeoutOffset   = mMetrics->emHeight * 0.3;
        mMetrics->strikeoutSize     = face->underline_thickness * yScale;
    }
    SnapLineToPixels(mMetrics->strikeoutOffset, mMetrics->strikeoutSize);

    // seems that underlineOffset really has to be negative
    mMetrics->underlineOffset = face->underline_position * yScale;
    mMetrics->underlineSize   = face->underline_thickness * yScale;

    // descents are negative in FT but Thebes wants them positive
    mMetrics->emAscent        = face->ascender * yScale;
    mMetrics->emDescent       = -face->descender * yScale;
    mMetrics->maxHeight       = face->height * yScale;
    // the max units determine frame heights, better be generous
    mMetrics->maxAscent       = PR_MAX(face->bbox.yMax * yScale,
                                       mMetrics->emAscent);
    mMetrics->maxDescent      = PR_MAX(-face->bbox.yMin * yScale,
                                       mMetrics->emDescent);
    mMetrics->maxAdvance      = PR_MAX(face->max_advance_width * xScale,
                                       mMetrics->aveCharWidth);

    // leadings are not available directly (only for WinFNTs);
    // better compute them on our own, to get integer values and make
    // layout happy (see // LockedFTFace::GetMetrics in gfxPangoFonts.cpp)
    mMetrics->internalLeading = NS_floor(mMetrics->maxHeight
                                         - mMetrics->emHeight + 0.5);
    gfxFloat lineHeight = NS_floor(mMetrics->maxHeight + 0.5);
    mMetrics->externalLeading = lineHeight
                              - mMetrics->internalLeading - mMetrics->emHeight;

    SanitizeMetrics(mMetrics, PR_FALSE);

#ifdef DEBUG_thebes_1
    printf("gfxOS2Font[%#x]::GetMetrics():\n"
           "  %s (%s)\n"
           "  emHeight=%f == %f=gfxFont::style.size == %f=adjSz\n"
           "  maxHeight=%f  xHeight=%f\n"
           "  aveCharWidth=%f(x) zeroOrAveWidth=%f(0) spaceWidth=%f\n"
           "  supOff=%f SubOff=%f   strOff=%f strSz=%f\n"
           "  undOff=%f undSz=%f    intLead=%f extLead=%f\n"
           "  emAsc=%f emDesc=%f maxH=%f\n"
           "  maxAsc=%f maxDes=%f maxAdv=%f\n",
           (unsigned)this,
           NS_LossyConvertUTF16toASCII(GetName()).get(),
           os2 && os2->version != 0xFFFF ? "has OS/2 table" : "no OS/2 table!",
           mMetrics->emHeight, GetStyle()->size, mAdjustedSize,
           mMetrics->maxHeight, mMetrics->xHeight,
           mMetrics->aveCharWidth, mMetrics->zeroOrAveCharWidth, mMetrics->spaceWidth,
           mMetrics->superscriptOffset, mMetrics->subscriptOffset,
           mMetrics->strikeoutOffset, mMetrics->strikeoutSize,
           mMetrics->underlineOffset, mMetrics->underlineSize,
           mMetrics->internalLeading, mMetrics->externalLeading,
           mMetrics->emAscent, mMetrics->emDescent, mMetrics->maxHeight,
           mMetrics->maxAscent, mMetrics->maxDescent, mMetrics->maxAdvance
          );
#endif
    cairo_ft_scaled_font_unlock_face(scaledFont);
    return *mMetrics;
}

// weight list copied from fontconfig.h
// unfortunately, the OS/2 version so far only supports regular and bold
static const PRInt8 nFcWeight = 2; // 10; // length of weight list
static const int fcWeight[] = {
    //FC_WEIGHT_THIN,
    //FC_WEIGHT_EXTRALIGHT, // == FC_WEIGHT_ULTRALIGHT
    //FC_WEIGHT_LIGHT,
    //FC_WEIGHT_BOOK,
    FC_WEIGHT_REGULAR, // == FC_WEIGHT_NORMAL
    //FC_WEIGHT_MEDIUM,
    //FC_WEIGHT_DEMIBOLD, // == FC_WEIGHT_SEMIBOLD
    FC_WEIGHT_BOLD,
    //FC_WEIGHT_EXTRABOLD, // == FC_WEIGHT_ULTRABOLD
    //FC_WEIGHT_BLACK // == FC_WEIGHT_HEAVY
};

// gfxOS2Font::CairoFontFace()
// return a font face usable by cairo for font rendering
// if none was created yet, use FontConfig patterns based on the current style
// to create a new font face
cairo_font_face_t *gfxOS2Font::CairoFontFace()
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2Font[%#x]::CairoFontFace()\n", (unsigned)this);
#endif
    if (!mFontFace) {
#ifdef DEBUG_thebes
        printf("gfxOS2Font[%#x]::CairoFontFace(): create it for %s, %f\n",
               (unsigned)this, NS_LossyConvertUTF16toASCII(GetName()).get(), GetStyle()->size);
#endif
        FcPattern *fcPattern = FcPatternCreate();

        // add (family) name to pattern
        // convert name because FC stores it in UTF8 while we have it in UTF16
        FcPatternAddString(fcPattern, FC_FAMILY,
                           (FcChar8 *)NS_ConvertUTF16toUTF8(GetName()).get());

        // The requirements outlined in gfxFont.h are difficult to meet without
        // having a table of available font weights, so we map the gfxFont
        // weight to possible FontConfig weights.
        PRInt8 weight = GetStyle()->ComputeWeight();
        // gfxFont weight   FC weight
        //    400              80
        //    700             200
        PRInt16 fcW = 40 * weight - 80; // match gfxFont weight to base FC weight
        // find the correct weight in the list
        PRInt8 i = 0;
        while (i < nFcWeight && fcWeight[i] < fcW) {
            i++;
        }
        if (i < 0) {
            i = 0;
        } else if (i >= nFcWeight) {
            i = nFcWeight - 1;
        }
        fcW = fcWeight[i];

        // add weight to pattern
        FcPatternAddInteger(fcPattern, FC_WEIGHT, fcW);

        PRUint8 fcProperty;
        // add style to pattern
        switch (GetStyle()->style) {
        case FONT_STYLE_ITALIC:
            fcProperty = FC_SLANT_ITALIC;
            break;
        case FONT_STYLE_OBLIQUE:
            fcProperty = FC_SLANT_OBLIQUE;
            break;
        case FONT_STYLE_NORMAL:
        default:
            fcProperty = FC_SLANT_ROMAN;
        }
        FcPatternAddInteger(fcPattern, FC_SLANT, fcProperty);

        // add the size we want
        FcPatternAddDouble(fcPattern, FC_PIXEL_SIZE,
                           mAdjustedSize ? mAdjustedSize : GetStyle()->size);

        // finally find a matching font
        FcResult fcRes;
        FcPattern *fcMatch = FcFontMatch(NULL, fcPattern, &fcRes);

        // Most code that depends on FcFontMatch() assumes it won't fail,
        // then crashes when it does.  For now, at least, substitute the
        // default serif font when it fails to avoid those crashes.
        if (!fcMatch) {
//#ifdef DEBUG
            printf("Could not match font for:\n"
                   "  family=%s, weight=%d, slant=%d, size=%f\n",
                   NS_LossyConvertUTF16toASCII(GetName()).get(),
                   GetStyle()->weight, GetStyle()->style, GetStyle()->size);
//#endif
            // FcPatternAddString() will free the existing FC_FAMILY string
            FcPatternAddString(fcPattern, FC_FAMILY, (FcChar8*)"SERIF");
            fcMatch = FcFontMatch(NULL, fcPattern, &fcRes);
//#ifdef DEBUG
            printf("Attempt to substitute default SERIF font %s\n",
                   fcMatch ? "succeeded" : "failed");
//#endif
        }
        FcPatternDestroy(fcPattern);

        if (fcMatch) {
            int w = FC_WEIGHT_REGULAR;
            FcPatternGetInteger(fcMatch, FC_WEIGHT, 0, &w);
            if (fcW >= FC_WEIGHT_DEMIBOLD && w < FC_WEIGHT_DEMIBOLD) {
                // if we want a bold font, but the selected font doesn't have a
                // bold counterpart, artificially embolden it
                FcPatternAddBool(fcMatch, FC_EMBOLDEN, FcTrue);
            }
            FcPatternAddBool(fcMatch, FC_ANTIALIAS, mAntialias);
            FcPatternAddInteger(fcMatch, FC_HINT_STYLE, mHinting);

            // and ask cairo to return a font face for this
            mFontFace = cairo_ft_font_face_create_for_pattern(fcMatch);

            FcPatternDestroy(fcMatch);
        }
    }

    NS_ASSERTION(mFontFace, "Failed to make font face");
    return mFontFace;
}

cairo_scaled_font_t *gfxOS2Font::CairoScaledFont()
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2Font[%#x]::CairoScaledFont()\n", (unsigned)this);
#endif
    if (mScaledFont) {
        return mScaledFont;
    }
#ifdef DEBUG_thebes_2
    printf("gfxOS2Font[%#x]::CairoScaledFont(): create it for %s, %f\n",
           (unsigned)this, NS_LossyConvertUTF16toASCII(GetName()).get(), GetStyle()->size);
#endif

    double size = mAdjustedSize ? mAdjustedSize : GetStyle()->size;
    cairo_matrix_t identityMatrix;
    cairo_matrix_init_identity(&identityMatrix);
    cairo_matrix_t fontMatrix;
    // synthetic oblique by skewing via the font matrix
    if (!mFontEntry->mItalic &&
        (mStyle.style & (FONT_STYLE_ITALIC | FONT_STYLE_OBLIQUE)))
    {
        const double kSkewFactor = 0.2126; // 12 deg skew as used in e.g. ftview
        cairo_matrix_init(&fontMatrix, size, 0, -kSkewFactor*size, size, 0, 0);
    } else {
        cairo_matrix_init_scale(&fontMatrix, size, size);
    }

    cairo_font_face_t * face = CairoFontFace();
    if (!face)
        return nsnull;

    cairo_font_options_t *fontOptions = cairo_font_options_create();
    mScaledFont = cairo_scaled_font_create(face, &fontMatrix,
                                           &identityMatrix, fontOptions);
    cairo_font_options_destroy(fontOptions);

    NS_ASSERTION(cairo_scaled_font_status(mScaledFont) == CAIRO_STATUS_SUCCESS,
                 "Failed to make scaled font");
    return mScaledFont;
}

nsString gfxOS2Font::GetUniqueName()
{
#ifdef DEBUG_thebes
    printf("gfxOS2Font::GetUniqueName()=%s\n", (char *)GetName().get());
#endif
    // gfxFont::GetName() should already be unique enough
    // Atsui uses that, too, while Win appends size, and properties...
    // doesn't seem to get called at all anyway
    return GetName();
}

PRBool gfxOS2Font::SetupCairoFont(gfxContext *aContext)
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2Font[%#x]::SetupCairoFont(%#x)\n",
           (unsigned)this, (unsigned) aContext);
#endif
    // gfxPangoFont checks the CTM but Windows doesn't so leave away here, too

    // this implicitely ensures that mScaledFont is created if NULL
    cairo_scaled_font_t *scaledFont = CairoScaledFont();
    if (!scaledFont || cairo_scaled_font_status(scaledFont) != CAIRO_STATUS_SUCCESS) {
        // Don't cairo_set_scaled_font as that would propagate the error to
        // the cairo_t, precluding any further drawing.
        return PR_FALSE;
    }
    cairo_set_scaled_font(aContext->GetCairo(), scaledFont);
    return PR_TRUE;
}

/**
 * Look up the font in the gfxFont cache. If we don't find it, create one.
 * In either case, add a ref and return it ---
 * except for OOM in which case we do nothing and return null.
 */
already_AddRefed<gfxOS2Font> gfxOS2Font::GetOrMakeFont(const nsAString& aName,
                                                       const gfxFontStyle *aStyle)
{
    nsRefPtr<gfxOS2FontEntry> fe = new gfxOS2FontEntry(aName);
    nsRefPtr<gfxFont> font =
      gfxFontCache::GetCache()->Lookup(static_cast<gfxFontEntry *>(fe), aStyle);
    if (!font) {
        font = new gfxOS2Font(fe, aStyle);
        if (!font)
            return nsnull;
        gfxFontCache::GetCache()->AddNew(font);
    }
    gfxFont *f = nsnull;
    font.swap(f);
    return static_cast<gfxOS2Font *>(f);
}

/**********************************************************************
 * class gfxOS2FontGroup
 **********************************************************************/

gfxOS2FontGroup::gfxOS2FontGroup(const nsAString& aFamilies,
                                 const gfxFontStyle* aStyle,
                                 gfxUserFontSet *aUserFontSet)
    : gfxFontGroup(aFamilies, aStyle, aUserFontSet)
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2FontGroup[%#x]::gfxOS2FontGroup(\"%s\", %#x)\n",
           (unsigned)this, NS_LossyConvertUTF16toASCII(aFamilies).get(),
           (unsigned)aStyle);
#endif

    // check for WarpSans and as we cannot display that (yet), replace
    // it with Workplace Sans
    int pos = 0;
    if ((pos = mFamilies.Find("WarpSans", PR_FALSE, 0, -1)) > -1) {
        mFamilies.Replace(pos, 8, NS_LITERAL_STRING("Workplace Sans"));
    }

    nsTArray<nsString> familyArray;
    ForEachFont(FontCallback, &familyArray);

    // To be able to easily search for glyphs in other fonts, append a few good
    // replacement candidates to the list. The best ones are the Unicode fonts that
    // are set up, and if the user was so clever to set up the User Defined fonts,
    // then these are probable candidates, too.
    nsString fontString;
    gfxPlatform::GetPlatform()->GetPrefFonts(gfxAtoms::x_unicode, fontString, PR_FALSE);
    ForEachFont(fontString, gfxAtoms::x_unicode, FontCallback, &familyArray);
    gfxPlatform::GetPlatform()->GetPrefFonts(gfxAtoms::x_user_def, fontString, PR_FALSE);
    ForEachFont(fontString, gfxAtoms::x_user_def, FontCallback, &familyArray);

    // Should append some default font if there are no available fonts.
    // Let's use Helv which should be available on any OS/2 system; if
    // it's not there, Fontconfig replaces it with something else...
    if (familyArray.Length() == 0) {
        familyArray.AppendElement(NS_LITERAL_STRING("Helv"));
    }

    for (PRUint32 i = 0; i < familyArray.Length(); i++) {
        nsRefPtr<gfxOS2Font> font = gfxOS2Font::GetOrMakeFont(familyArray[i], &mStyle);
        if (font) {
            mFonts.AppendElement(font);
        }
    }
}

gfxOS2FontGroup::~gfxOS2FontGroup()
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2FontGroup[%#x]::~gfxOS2FontGroup()\n", (unsigned)this);
#endif
}

gfxFontGroup *gfxOS2FontGroup::Copy(const gfxFontStyle *aStyle)
{
    return new gfxOS2FontGroup(mFamilies, aStyle, mUserFontSet);
}

/**
 * We use this to append an LTR or RTL Override character to the start of the
 * string. This forces Pango to honour our direction even if there are neutral
 * characters in the string.
 */
static PRInt32 AppendDirectionalIndicatorUTF8(PRBool aIsRTL, nsACString& aString)
{
    static const PRUnichar overrides[2][2] = { { 0x202d, 0 }, { 0x202e, 0 }}; // LRO, RLO
    AppendUTF16toUTF8(overrides[aIsRTL], aString);
    return 3; // both overrides map to 3 bytes in UTF8
}

gfxTextRun *gfxOS2FontGroup::MakeTextRun(const PRUnichar* aString, PRUint32 aLength,
                                         const Parameters* aParams, PRUint32 aFlags)
{
    NS_ASSERTION(aLength > 0, "should use MakeEmptyTextRun for zero-length text");
    gfxTextRun *textRun = gfxTextRun::Create(aParams, aString, aLength, this, aFlags);
    if (!textRun)
        return nsnull;

    mEnableKerning = !(aFlags & gfxTextRunFactory::TEXT_OPTIMIZE_SPEED);

    nsCAutoString utf8;
    PRInt32 headerLen = AppendDirectionalIndicatorUTF8(textRun->IsRightToLeft(), utf8);
    AppendUTF16toUTF8(Substring(aString, aString + aLength), utf8);

#ifdef DEBUG_thebes_2
    NS_ConvertUTF8toUTF16 u16(utf8);
    printf("gfxOS2FontGroup[%#x]::MakeTextRun(PRUnichar %s, %d, %#x, %d)\n",
           (unsigned)this, NS_LossyConvertUTF16toASCII(u16).get(), aLength, (unsigned)aParams, aFlags);
#endif

    InitTextRun(textRun, (PRUint8 *)utf8.get(), utf8.Length(), headerLen);

    textRun->FetchGlyphExtents(aParams->mContext);

    return textRun;
}

gfxTextRun *gfxOS2FontGroup::MakeTextRun(const PRUint8* aString, PRUint32 aLength,
                                         const Parameters* aParams, PRUint32 aFlags)
{
#ifdef DEBUG_thebes_2
    const char *cStr = reinterpret_cast<const char *>(aString);
    NS_ConvertASCIItoUTF16 us(cStr, aLength);
    printf("gfxOS2FontGroup[%#x]::MakeTextRun(PRUint8 %s, %d, %#x, %d)\n",
           (unsigned)this, NS_LossyConvertUTF16toASCII(us).get(), aLength, (unsigned)aParams, aFlags);
#endif
    NS_ASSERTION(aLength > 0, "should use MakeEmptyTextRun for zero-length text");
    NS_ASSERTION(aFlags & TEXT_IS_8BIT, "8bit should have been set");
    gfxTextRun *textRun = gfxTextRun::Create(aParams, aString, aLength, this, aFlags);
    if (!textRun)
        return nsnull;

    mEnableKerning = !(aFlags & gfxTextRunFactory::TEXT_OPTIMIZE_SPEED);

    const char *chars = reinterpret_cast<const char *>(aString);
    PRBool isRTL = textRun->IsRightToLeft();
    if ((aFlags & TEXT_IS_ASCII) && !isRTL) {
        // We don't need to send an override character here, the characters must be all
        // LTR
        InitTextRun(textRun, (PRUint8 *)chars, aLength, 0);
    } else {
        // Although chars in not necessarily ASCII (as it may point to the low
        // bytes of any UCS-2 characters < 256), NS_ConvertASCIItoUTF16 seems
        // to DTRT.
        NS_ConvertASCIItoUTF16 unicodeString(chars, aLength);
        nsCAutoString utf8;
        PRInt32 headerLen = AppendDirectionalIndicatorUTF8(isRTL, utf8);
        AppendUTF16toUTF8(unicodeString, utf8);
        InitTextRun(textRun, (PRUint8 *)utf8.get(), utf8.Length(), headerLen);
    }

    textRun->FetchGlyphExtents(aParams->mContext);

    return textRun;
}

void gfxOS2FontGroup::InitTextRun(gfxTextRun *aTextRun, const PRUint8 *aUTF8Text,
                                  PRUint32 aUTF8Length,
                                  PRUint32 aUTF8HeaderLength)
{
    CreateGlyphRunsFT(aTextRun, aUTF8Text + aUTF8HeaderLength,
                      aUTF8Length - aUTF8HeaderLength);
}

// Helper function to return the leading UTF-8 character in a char pointer
// as 32bit number. Also sets the length of the current character (i.e. the
// offset to the next one) in the second argument
PRUint32 getUTF8CharAndNext(const PRUint8 *aString, PRUint8 *aLength)
{
    *aLength = 1;
    if (aString[0] < 0x80) { // normal 7bit ASCII char
        return aString[0];
    }
    if ((aString[0] >> 5) == 6) { // two leading ones -> two bytes
        *aLength = 2;
        return ((aString[0] & 0x1F) << 6) + (aString[1] & 0x3F);
    }
    if ((aString[0] >> 4) == 14) { // three leading ones -> three bytes
        *aLength = 3;
        return ((aString[0] & 0x0F) << 12) + ((aString[1] & 0x3F) << 6) +
               (aString[2] & 0x3F);
    }
    if ((aString[0] >> 4) == 15) { // four leading ones -> four bytes
        *aLength = 4;
        return ((aString[0] & 0x07) << 18) + ((aString[1] & 0x3F) << 12) +
               ((aString[2] & 0x3F) <<  6) + (aString[3] & 0x3F);
    }
    return aString[0];
}

void gfxOS2FontGroup::CreateGlyphRunsFT(gfxTextRun *aTextRun, const PRUint8 *aUTF8,
                                        PRUint32 aUTF8Length)
{
#ifdef DEBUG_thebes_2
    printf("gfxOS2FontGroup::CreateGlyphRunsFT(%#x, _aUTF8_, %d)\n",
           (unsigned)aTextRun, /*aUTF8,*/ aUTF8Length);
    for (PRUint32 i = 0; i < FontListLength(); i++) {
        gfxOS2Font *font = GetFontAt(i);
        printf("  i=%d, name=%s, size=%f\n", i, NS_LossyConvertUTF16toASCII(font->GetName()).get(),
               font->GetStyle()->size);
    }
#endif
    PRUint32 lastFont = FontListLength()-1;
    gfxOS2Font *font0 = GetFontAt(0);
    const PRUint8 *p = aUTF8;
    PRUint32 utf16Offset = 0;
    gfxTextRun::CompressedGlyph g;
    const PRUint32 appUnitsPerDevUnit = aTextRun->GetAppUnitsPerDevUnit();
    gfxOS2Platform *platform = gfxOS2Platform::GetPlatform();

    aTextRun->AddGlyphRun(font0, 0);
    // a textRun likely has the same font for most of the characters, so we can
    // lock it before the loop for efficiency
    FT_Face face0 = cairo_ft_scaled_font_lock_face(font0->CairoScaledFont());
    while (p < aUTF8 + aUTF8Length) {
        PRBool glyphFound = PR_FALSE;
        // convert UTF-8 character and step to the next one in line
        PRUint8 chLen;
        PRUint32 ch = getUTF8CharAndNext(p, &chLen);
        p += chLen; // move to next char
#ifdef DEBUG_thebes_2
        printf("\'%c\' (%d, %#x, %s) [%#x %#x]:", (char)ch, ch, ch, ch >=0x10000 ? "non-BMP!" : "BMP", ch >=0x10000 ? H_SURROGATE(ch) : 0, ch >=0x10000 ? L_SURROGATE(ch) : 0);
#endif

        if (ch == 0 || platform->noFontWithChar(ch)) {
            // null bytes or missing characters cannot be displayed
            aTextRun->SetMissingGlyph(utf16Offset, ch);
        } else {
            // Try to get a glyph from all fonts available to us.
            // Once we found it in one of the fonts we quit the loop early.
            // If we don't find the glyph even in the last font, we will fall
            // back to searching all fonts on the system and finally set the
            // missing glyph symbol after trying the last font.
            for (PRUint32 i = 0; i <= lastFont; i++) {
                gfxOS2Font *font = font0;
                FT_Face face = face0;
                if (i > 0) {
                    font = GetFontAt(i);
                    face = cairo_ft_scaled_font_lock_face(font->CairoScaledFont());
#ifdef DEBUG_thebes_2
                    if (i == lastFont) {
                        printf("Last font %d (%s) for ch=%#x (pos=%d)",
                               i, NS_LossyConvertUTF16toASCII(font->GetName()).get(), ch, utf16Offset);
                    }
#endif
                }
                if (!face || !face->charmap) { // don't try to use fonts with non-Unicode charmaps
                    if (face && face != face0)
                        cairo_ft_scaled_font_unlock_face(font->CairoScaledFont());
                    continue; // next font
                }

                NS_ASSERTION(!IsInvalidChar(ch), "Invalid char detected");
                FT_UInt gid = FT_Get_Char_Index(face, ch); // find the glyph id

                if (gid == 0 && i == lastFont) {
                    // missing glyph, try to find a replacement in another font
                    nsRefPtr<gfxOS2Font> fontX = platform->FindFontForChar(ch, font0);
                    if (fontX) {
                        font = fontX; // replace current font
                        cairo_ft_scaled_font_unlock_face(font->CairoScaledFont());
                        face = cairo_ft_scaled_font_lock_face(fontX->CairoScaledFont());
                        gid = FT_Get_Char_Index(face, ch);
                        // likely to find more chars in this font, append it
                        // to the font list to find it quicker next time
                        mFonts.AppendElement(fontX);
                        lastFont = FontListLength()-1;
                    }
                }

                // select the current font into the text run
                aTextRun->AddGlyphRun(font, utf16Offset);

                PRInt32 advance = 0;
                if (gid == font->GetSpaceGlyph()) {
                    advance = (int)(font->GetMetrics().spaceWidth * appUnitsPerDevUnit);
                } else if (gid == 0) {
                    advance = -1; // trigger the missing glyphs case below
                } else {
                    // find next character and its glyph -- in case they exist
                    // and exist in the current font face -- to compute kerning
                    PRUint32 chNext = 0;
                    FT_UInt gidNext = 0;
                    FT_Pos lsbDeltaNext = 0;
#ifdef DEBUG_thebes_2
                    printf("(kerning=%s/%s)", mEnableKerning ? "enable" : "disable", FT_HAS_KERNING(face) ? "yes" : "no");
#endif
                    if (mEnableKerning && FT_HAS_KERNING(face) && p < aUTF8 + aUTF8Length) {
                        chNext = getUTF8CharAndNext(p, &chLen);
                        if (chNext) {
                            gidNext = FT_Get_Char_Index(face, chNext);
                            if (gidNext && gidNext != font->GetSpaceGlyph()) {
                                FT_Load_Glyph(face, gidNext, FT_LOAD_DEFAULT);
                                lsbDeltaNext = face->glyph->lsb_delta;
                            }
                        }
                    }

                    // now load the current glyph
                    FT_Load_Glyph(face, gid, FT_LOAD_DEFAULT); // load glyph into the slot
                    advance = face->glyph->advance.x;

                    // now add kerning to the current glyph's advance
                    if (chNext && gidNext) {
                        FT_Vector kerning;
                        FT_Get_Kerning(face, gid, gidNext, FT_KERNING_DEFAULT, &kerning);
                        advance += kerning.x;
                        if (face->glyph->rsb_delta - lsbDeltaNext >= 32) {
                            advance -= 64;
                        } else if (face->glyph->rsb_delta - lsbDeltaNext < -32) {
                            advance += 64;
                        }
                    }

                    // now apply unit conversion and scaling
                    advance = (advance >> 6) * appUnitsPerDevUnit;
                }
#ifdef DEBUG_thebes_2
                printf(" gid=%d, advance=%d (%s)\n", gid, advance,
                       NS_LossyConvertUTF16toASCII(font->GetName()).get());
#endif

                if (advance >= 0 &&
                    gfxTextRun::CompressedGlyph::IsSimpleAdvance(advance) &&
                    gfxTextRun::CompressedGlyph::IsSimpleGlyphID(gid))
                {
                    aTextRun->SetSimpleGlyph(utf16Offset,
                                             g.SetSimpleGlyph(advance, gid));
                    glyphFound = PR_TRUE;
                } else if (gid == 0) {
                    // gid = 0 only happens when the glyph is missing from the font
                    if (i == lastFont) {
                        // set the missing glyph only when it's missing from the very
                        // last font
                        aTextRun->SetMissingGlyph(utf16Offset, ch);
                    }
                    glyphFound = PR_FALSE;
                } else {
                    gfxTextRun::DetailedGlyph details;
                    details.mGlyphID = gid;
                    NS_ASSERTION(details.mGlyphID == gid, "Seriously weird glyph ID detected!");
                    details.mAdvance = advance;
                    details.mXOffset = 0;
                    details.mYOffset = 0;
                    g.SetComplex(aTextRun->IsClusterStart(utf16Offset), PR_TRUE, 1);
                    aTextRun->SetGlyphs(utf16Offset, g, &details);
                    glyphFound = PR_TRUE;
                }

                if (i > 0) {
                    cairo_ft_scaled_font_unlock_face(font->CairoScaledFont());
                }

                if (glyphFound) {
                    break;
                }
            }
        } // for all fonts

        NS_ASSERTION(!IS_SURROGATE(ch), "Surrogates shouldn't appear in UTF8");
        if (ch >= 0x10000) {
            // This character is a surrogate pair in UTF16
            ++utf16Offset;
        }

        ++utf16Offset;
    }
    cairo_ft_scaled_font_unlock_face(font0->CairoScaledFont());
}

// append aFontName to aClosure string array, if not already present
PRBool gfxOS2FontGroup::FontCallback(const nsAString& aFontName,
                                     const nsACString& aGenericName,
                                     void *aClosure)
{
    nsTArray<nsString> *sa = static_cast<nsTArray<nsString>*>(aClosure);
    if (!aFontName.IsEmpty() && !sa->Contains(aFontName)) {
        sa->AppendElement(aFontName);
    }
    return PR_TRUE;
}