starmath/source/rect.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <osl/diagnose.h>
  21 #include <vcl/svapp.hxx>
  22 #include <vcl/wrkwin.hxx>
  23 #include <vcl/virdev.hxx>
  24
  25
  26 #include "rect.hxx"
  27 #include "types.hxx"
  28 #include "utility.hxx"
  29 #include "smmod.hxx"
  30
  31
  32
  33
  34
  35 // '\0' terminated Array with symbol, which should be treat as letters in
  36 // StarMath Font, (to get a normal (non-clipped) SmRect in contrast to the
  37 // other operators and symbols).
  38 static sal_Unicode const aMathAlpha[] =
  39 {
  40     MS_ALEPH,               MS_IM,                  MS_RE,
  41     MS_WP,                  sal_Unicode(0xE070),    MS_EMPTYSET,
  42     sal_Unicode(0x2113),    sal_Unicode(0xE0D6),    sal_Unicode(0x2107),
  43     sal_Unicode(0x2127),    sal_Unicode(0x210A),    MS_HBAR,
  44     MS_LAMBDABAR,           MS_SETN,                MS_SETZ,
  45     MS_SETQ,                MS_SETR,                MS_SETC,
  46     sal_Unicode(0x2373),    sal_Unicode(0xE0A5),    sal_Unicode(0x2112),
  47     sal_Unicode(0x2130),    sal_Unicode(0x2131),
  48     sal_Unicode('\0')
  49 };
  50
  51 bool SmIsMathAlpha(const OUString &rText)
  52     // true iff symbol (from StarMath Font) should be treated as letter
  53 {
  54     if (rText.isEmpty())
  55         return false;
  56
  57     OSL_ENSURE(rText.getLength() == 1, "Sm : string must be exactly one character long");
  58     sal_Unicode cChar = rText[0];
  59
  60     // is it a greek symbol?
  61     if (sal_Unicode(0xE0AC) <= cChar  &&  cChar <= sal_Unicode(0xE0D4))
  62         return true;
  63     else
  64     {
  65         // appears it in 'aMathAlpha'?
  66         const sal_Unicode *pChar = aMathAlpha;
  67         while (*pChar  &&  *pChar != cChar)
  68             pChar++;
  69         return *pChar != '\0';
  70     }
  71 }
  72
  73
  74
  75
  76 // SmRect members
  77
  78
  79
  80 SmRect::SmRect()
  81     // constructs empty rectangle at (0, 0) with width and height 0.
  82 {
  83     OSL_ENSURE(aTopLeft == Point(0, 0), "Sm: ooops...");
  84     OSL_ENSURE(aSize == Size(0, 0), "Sm: ooops...");
  85
  86     bHasBaseline = bHasAlignInfo = false;
  87     nBaseline = nAlignT = nAlignM = nAlignB =
  88     nGlyphTop = nGlyphBottom =
  89     nItalicLeftSpace = nItalicRightSpace =
  90     nLoAttrFence = nHiAttrFence = 0;
  91     nBorderWidth = 0;
  92 }
  93
  94
  95 SmRect::SmRect(const SmRect &rRect)
  96 :   aTopLeft(rRect.aTopLeft),
  97     aSize(rRect.aSize)
  98 {
  99     bHasBaseline  = rRect.bHasBaseline;
 100     nBaseline     = rRect.nBaseline;
 101     nAlignT       = rRect.nAlignT;
 102     nAlignM       = rRect.nAlignM;
 103     nAlignB       = rRect.nAlignB;
 104     nGlyphTop     = rRect.nGlyphTop;
 105     nGlyphBottom  = rRect.nGlyphBottom;
 106     nHiAttrFence  = rRect.nHiAttrFence;
 107     nLoAttrFence  = rRect.nLoAttrFence;
 108     bHasAlignInfo = rRect.bHasAlignInfo;
 109     nItalicLeftSpace  = rRect.nItalicLeftSpace;
 110     nItalicRightSpace = rRect.nItalicRightSpace;
 111     nBorderWidth  = rRect.nBorderWidth;
 112 }
 113
 114
 115 void SmRect::CopyAlignInfo(const SmRect &rRect)
 116 {
 117     nBaseline     = rRect.nBaseline;
 118     bHasBaseline  = rRect.bHasBaseline;
 119     nAlignT       = rRect.nAlignT;
 120     nAlignM       = rRect.nAlignM;
 121     nAlignB       = rRect.nAlignB;
 122     bHasAlignInfo = rRect.bHasAlignInfo;
 123     nLoAttrFence  = rRect.nLoAttrFence;
 124     nHiAttrFence  = rRect.nHiAttrFence;
 125 }
 126
 127
 128 void SmRect::BuildRect(const OutputDevice &rDev, const SmFormat *pFormat,
 129                        const OUString &rText, sal_uInt16 nBorder)
 130 {
 131     OSL_ENSURE(aTopLeft == Point(0, 0), "Sm: Ooops...");
 132
 133     aSize = Size(rDev.GetTextWidth(rText), rDev.GetTextHeight());
 134
 135     const FontMetric  aFM (rDev.GetFontMetric());
 136     bool              bIsMath  = aFM.GetName().equalsIgnoreAsciiCase( FONTNAME_MATH );
 137     bool              bAllowSmaller = bIsMath && !SmIsMathAlpha(rText);
 138     const long        nFontHeight = rDev.GetFont().GetSize().Height();
 139
 140     nBorderWidth  = nBorder;
 141     bHasAlignInfo = true;
 142     bHasBaseline  = true;
 143     nBaseline     = aFM.GetAscent();
 144     nAlignT       = nBaseline - nFontHeight * 750L / 1000L;
 145     nAlignM       = nBaseline - nFontHeight * 121L / 422L;
 146         // that's where the horizontal bars of '+', '-', ... are
 147         // (1/3 of ascent over baseline)
 148         // (121 = 1/3 of 12pt ascent, 422 = 12pt fontheight)
 149     nAlignB       = nBaseline;
 150
 151     // workaround for printer fonts with very small (possible 0 or even
 152     // negative(!)) leading
 153     if (aFM.GetIntLeading() < 5  &&  rDev.GetOutDevType() == OUTDEV_PRINTER)
 154     {
 155         OutputDevice    *pWindow = Application::GetDefaultDevice();
 156
 157         pWindow->Push(PushFlags::MAPMODE | PushFlags::FONT);
 158
 159         pWindow->SetMapMode(rDev.GetMapMode());
 160         pWindow->SetFont(rDev.GetFontMetric());
 161
 162         long  nDelta = pWindow->GetFontMetric().GetIntLeading();
 163         if (nDelta == 0)
 164         {   // this value approx. fits a Leading of 80 at a
 165             // Fontheight of 422 (12pt)
 166             nDelta = nFontHeight * 8L / 43;
 167         }
 168         SetTop(GetTop() - nDelta);
 169
 170         pWindow->Pop();
 171     }
 172
 173     // get GlyphBoundRect
 174     Rectangle  aGlyphRect;
 175     bool bSuccess = SmGetGlyphBoundRect(rDev, rText, aGlyphRect);
 176     if (!bSuccess)
 177         SAL_WARN("starmath", "Ooops... (Font missing?)");
 178
 179     nItalicLeftSpace  = GetLeft() - aGlyphRect.Left() + nBorderWidth;
 180     nItalicRightSpace = aGlyphRect.Right() - GetRight() + nBorderWidth;
 181     if (nItalicLeftSpace  < 0  &&  !bAllowSmaller)
 182         nItalicLeftSpace  = 0;
 183     if (nItalicRightSpace < 0  &&  !bAllowSmaller)
 184         nItalicRightSpace = 0;
 185
 186     long  nDist = 0;
 187     if (pFormat)
 188         nDist = (rDev.GetFont().GetSize().Height()
 189                 * pFormat->GetDistance(DIS_ORNAMENTSIZE)) / 100L;
 190
 191     nHiAttrFence = aGlyphRect.TopLeft().Y() - 1 - nBorderWidth - nDist;
 192     nLoAttrFence = SmFromTo(GetAlignB(), GetBottom(), 0.0);
 193
 194     nGlyphTop    = aGlyphRect.Top() - nBorderWidth;
 195     nGlyphBottom = aGlyphRect.Bottom() + nBorderWidth;
 196
 197     if (bAllowSmaller)
 198     {
 199         // for symbols and operators from the StarMath Font
 200         // we adjust upper and lower margin of the symbol
 201         SetTop(nGlyphTop);
 202         SetBottom(nGlyphBottom);
 203     }
 204
 205     if (nHiAttrFence < GetTop())
 206         nHiAttrFence = GetTop();
 207
 208     if (nLoAttrFence > GetBottom())
 209         nLoAttrFence = GetBottom();
 210
 211     OSL_ENSURE(rText.isEmpty() || !IsEmpty(),
 212                "Sm: empty rectangle created");
 213 }
 214
 215
 216 void SmRect::Init(const OutputDevice &rDev, const SmFormat *pFormat,
 217                   const OUString &rText, sal_uInt16 nEBorderWidth)
 218     // get rectangle fitting for drawing 'rText' on OutputDevice 'rDev'
 219 {
 220     BuildRect(rDev, pFormat, rText, nEBorderWidth);
 221 }
 222
 223
 224 SmRect::SmRect(const OutputDevice &rDev, const SmFormat *pFormat,
 225                const OUString &rText, long nEBorderWidth)
 226 {
 227     OSL_ENSURE( nEBorderWidth >= 0, "BorderWidth is negative" );
 228     if (nEBorderWidth < 0)
 229         nEBorderWidth = 0;
 230     Init(rDev, pFormat, rText, (sal_uInt16) nEBorderWidth);
 231 }
 232
 233
 234 SmRect::SmRect(long nWidth, long nHeight)
 235     // this constructor should never be used for anything textlike because
 236     // it will not provide useful values for baseline, AlignT and AlignB!
 237     // It's purpose is to get a 'SmRect' for the horizontal line in fractions
 238     // as used in 'SmBinVerNode'.
 239 :   aSize(nWidth, nHeight)
 240 {
 241     OSL_ENSURE(aTopLeft == Point(0, 0), "Sm: ooops...");
 242
 243     bHasBaseline  = false;
 244     bHasAlignInfo = true;
 245     nBaseline     = 0;
 246     nAlignT       = GetTop();
 247     nAlignB       = GetBottom();
 248     nAlignM       = (nAlignT + nAlignB) / 2;        // this is the default
 249     nItalicLeftSpace = nItalicRightSpace = 0;
 250     nGlyphTop    = nHiAttrFence  = GetTop();
 251     nGlyphBottom = nLoAttrFence  = GetBottom();
 252     nBorderWidth  = 0;
 253 }
 254
 255
 256 void SmRect::SetLeft(long nLeft)
 257 {
 258     if (nLeft <= GetRight())
 259     {   aSize.Width() = GetRight() - nLeft + 1;
 260         aTopLeft.X()  = nLeft;
 261     }
 262 }
 263
 264
 265 void SmRect::SetRight(long nRight)
 266 {
 267     if (nRight >= GetLeft())
 268         aSize.Width() = nRight - GetLeft() + 1;
 269 }
 270
 271
 272 void SmRect::SetBottom(long nBottom)
 273 {
 274     if (nBottom >= GetTop())
 275         aSize.Height() = nBottom - GetTop() + 1;
 276 }
 277
 278
 279 void SmRect::SetTop(long nTop)
 280 {
 281     if (nTop <= GetBottom())
 282     {   aSize.Height()   = GetBottom() - nTop + 1;
 283         aTopLeft.Y() = nTop;
 284     }
 285 }
 286
 287
 288 void SmRect::Move(const Point &rPosition)
 289     // move rectangle by position 'rPosition'.
 290 {
 291     aTopLeft  += rPosition;
 292
 293     long  nDelta = rPosition.Y();
 294     nBaseline += nDelta;
 295     nAlignT   += nDelta;
 296     nAlignM   += nDelta;
 297     nAlignB   += nDelta;
 298     nGlyphTop    += nDelta;
 299     nGlyphBottom += nDelta;
 300     nHiAttrFence += nDelta;
 301     nLoAttrFence += nDelta;
 302 }
 303
 304
 305 const Point SmRect::AlignTo(const SmRect &rRect, RectPos ePos,
 306                             RectHorAlign eHor, RectVerAlign eVer) const
 307 {   Point  aPos (GetTopLeft());
 308         // will become the topleft point of the new rectangle position
 309
 310     // set horizontal or vertical new rectangle position depending on
 311     // 'ePos' is one of 'RP_LEFT', 'RP_RIGHT' or 'RP_TOP', 'RP_BOTTOM'
 312     switch (ePos)
 313     {   case RP_LEFT :
 314             aPos.X() = rRect.GetItalicLeft() - GetItalicRightSpace()
 315                        - GetWidth();
 316             break;
 317         case RP_RIGHT :
 318             aPos.X() = rRect.GetItalicRight() + 1 + GetItalicLeftSpace();
 319             break;
 320         case RP_TOP :
 321             aPos.Y() = rRect.GetTop() - GetHeight();
 322             break;
 323         case RP_BOTTOM :
 324             aPos.Y() = rRect.GetBottom() + 1;
 325             break;
 326         case RP_ATTRIBUT :
 327             aPos.X() = rRect.GetItalicCenterX() - GetItalicWidth() / 2
 328                        + GetItalicLeftSpace();
 329             break;
 330         default :
 331             SAL_WARN("starmath", "unknown case");
 332     }
 333
 334     // check if horizontal position is already set
 335     if (ePos == RP_LEFT  ||  ePos == RP_RIGHT  ||  ePos == RP_ATTRIBUT)
 336         // correct error in current vertical position
 337         switch (eVer)
 338         {   case RVA_TOP :
 339                 aPos.Y() += rRect.GetAlignT() - GetAlignT();
 340                 break;
 341             case RVA_MID :
 342                 aPos.Y() += rRect.GetAlignM() - GetAlignM();
 343                 break;
 344             case RVA_BASELINE :
 345                 // align baselines if possible else align mid's
 346                 if (HasBaseline() && rRect.HasBaseline())
 347                     aPos.Y() += rRect.GetBaseline() - GetBaseline();
 348                 else
 349                     aPos.Y() += rRect.GetAlignM() - GetAlignM();
 350                 break;
 351             case RVA_BOTTOM :
 352                 aPos.Y() += rRect.GetAlignB() - GetAlignB();
 353                 break;
 354             case RVA_CENTERY :
 355                 aPos.Y() += rRect.GetCenterY() - GetCenterY();
 356                 break;
 357             case RVA_ATTRIBUT_HI:
 358                 aPos.Y() += rRect.GetHiAttrFence() - GetBottom();
 359                 break;
 360             case RVA_ATTRIBUT_MID :
 361                 aPos.Y() += SmFromTo(rRect.GetAlignB(), rRect.GetAlignT(), 0.4)
 362                             - GetCenterY();
 363                 break;
 364             case RVA_ATTRIBUT_LO :
 365                 aPos.Y() += rRect.GetLoAttrFence() - GetTop();
 366                 break;
 367         default :
 368                 SAL_WARN("starmath", "unknown case");
 369         }
 370
 371     // check if vertical position is already set
 372     if (ePos == RP_TOP  ||  ePos == RP_BOTTOM)
 373         // correct error in current horizontal position
 374         switch (eHor)
 375         {   case RHA_LEFT :
 376                 aPos.X() += rRect.GetItalicLeft() - GetItalicLeft();
 377                 break;
 378             case RHA_CENTER :
 379                 aPos.X() += rRect.GetItalicCenterX() - GetItalicCenterX();
 380                 break;
 381             case RHA_RIGHT :
 382                 aPos.X() += rRect.GetItalicRight() - GetItalicRight();
 383                 break;
 384             default :
 385                 SAL_WARN("starmath", "unknown case");
 386         }
 387
 388     return aPos;
 389 }
 390
 391
 392 SmRect & SmRect::Union(const SmRect &rRect)
 393     // rectangle union of current one with 'rRect'. The result is to be the
 394     // smallest rectangles that covers the space of both rectangles.
 395     // (empty rectangles cover no space)
 396     //! Italic correction is NOT taken into account here!
 397 {
 398     if (rRect.IsEmpty())
 399         return *this;
 400
 401     long  nL  = rRect.GetLeft(),
 402           nR  = rRect.GetRight(),
 403           nT  = rRect.GetTop(),
 404           nB  = rRect.GetBottom(),
 405           nGT = rRect.nGlyphTop,
 406           nGB = rRect.nGlyphBottom;
 407     if (!IsEmpty())
 408     {   long  nTmp;
 409
 410         if ((nTmp = GetLeft()) < nL)
 411             nL = nTmp;
 412         if ((nTmp = GetRight()) > nR)
 413             nR = nTmp;
 414         if ((nTmp = GetTop()) < nT)
 415             nT = nTmp;
 416         if ((nTmp = GetBottom()) > nB)
 417             nB = nTmp;
 418         if ((nTmp = nGlyphTop) < nGT)
 419             nGT = nTmp;
 420         if ((nTmp = nGlyphBottom) > nGB)
 421             nGB = nTmp;
 422     }
 423
 424     SetLeft(nL);
 425     SetRight(nR);
 426     SetTop(nT);
 427     SetBottom(nB);
 428     nGlyphTop    = nGT;
 429     nGlyphBottom = nGB;
 430
 431     return *this;
 432 }
 433
 434
 435 SmRect & SmRect::ExtendBy(const SmRect &rRect, RectCopyMBL eCopyMode)
 436     // let current rectangle be the union of itself and 'rRect'
 437     // (the smallest rectangle surrounding both). Also adapt values for
 438     // 'AlignT', 'AlignM', 'AlignB', baseline and italic-spaces.
 439     // The baseline is set according to 'eCopyMode'.
 440     // If one of the rectangles has no relevant info the other one is copied.
 441 {
 442     // get some values used for (italic) spaces adaption
 443     // ! (need to be done before changing current SmRect) !
 444     long  nL = std::min(GetItalicLeft(),  rRect.GetItalicLeft()),
 445           nR = std::max(GetItalicRight(), rRect.GetItalicRight());
 446
 447     Union(rRect);
 448
 449     SetItalicSpaces(GetLeft() - nL, nR - GetRight());
 450
 451     if (!HasAlignInfo())
 452         CopyAlignInfo(rRect);
 453     else if (rRect.HasAlignInfo())
 454     {   nAlignT = std::min(GetAlignT(), rRect.GetAlignT());
 455         nAlignB = std::max(GetAlignB(), rRect.GetAlignB());
 456         nHiAttrFence = std::min(GetHiAttrFence(), rRect.GetHiAttrFence());
 457         nLoAttrFence = std::max(GetLoAttrFence(), rRect.GetLoAttrFence());
 458         OSL_ENSURE(HasAlignInfo(), "Sm: ooops...");
 459
 460         switch (eCopyMode)
 461         {   case RCP_THIS:
 462                 // already done
 463                 break;
 464             case RCP_ARG:
 465                 CopyMBL(rRect);
 466                 break;
 467             case RCP_NONE:
 468                 ClearBaseline();
 469                 nAlignM = (nAlignT + nAlignB) / 2;
 470                 break;
 471             case RCP_XOR:
 472                 if (!HasBaseline())
 473                     CopyMBL(rRect);
 474                 break;
 475             default :
 476                 SAL_WARN("starmath", "unknown case");
 477         }
 478     }
 479
 480     return *this;
 481 }
 482
 483
 484 SmRect & SmRect::ExtendBy(const SmRect &rRect, RectCopyMBL eCopyMode,
 485                           long nNewAlignM)
 486     // as 'ExtendBy' but sets AlignM value to 'nNewAlignM'.
 487     // (this version will be used in 'SmBinVerNode' to provide means to
 488     // align eg "{a over b} over c" correctly where AlignM should not
 489     // be (AlignT + AlignB) / 2)
 490 {
 491     OSL_ENSURE(HasAlignInfo(), "Sm: no align info");
 492
 493     ExtendBy(rRect, eCopyMode);
 494     nAlignM = nNewAlignM;
 495
 496     return *this;
 497 }
 498
 499
 500 SmRect & SmRect::ExtendBy(const SmRect &rRect, RectCopyMBL eCopyMode,
 501                           bool bKeepVerAlignParams)
 502     // as 'ExtendBy' but keeps original values for AlignT, -M and -B and
 503     // baseline.
 504     // (this is used in 'SmSupSubNode' where the sub-/supscripts shouldn't
 505     // be allowed to modify these values.)
 506 {
 507     long  nOldAlignT   = GetAlignT(),
 508           nOldAlignM   = GetAlignM(),
 509           nOldAlignB   = GetAlignB(),
 510           nOldBaseline = nBaseline;     //! depends not on 'HasBaseline'
 511     bool  bOldHasAlignInfo = HasAlignInfo();
 512
 513     ExtendBy(rRect, eCopyMode);
 514
 515     if (bKeepVerAlignParams)
 516     {   nAlignT   = nOldAlignT;
 517         nAlignM   = nOldAlignM;
 518         nAlignB   = nOldAlignB;
 519         nBaseline = nOldBaseline;
 520         bHasAlignInfo = bOldHasAlignInfo;
 521     }
 522
 523     return *this;
 524 }
 525
 526
 527 long SmRect::OrientedDist(const Point &rPoint) const
 528     // return oriented distance of rPoint to the current rectangle,
 529     // especially the return value is <= 0 iff the point is inside the
 530     // rectangle.
 531     // For simplicity the maximum-norm is used.
 532 {
 533     bool  bIsInside = IsInsideItalicRect(rPoint);
 534
 535     // build reference point to define the distance
 536     Point  aRef;
 537     if (bIsInside)
 538     {   Point  aIC (GetItalicCenterX(), GetCenterY());
 539
 540         aRef.X() = rPoint.X() >= aIC.X() ? GetItalicRight() : GetItalicLeft();
 541         aRef.Y() = rPoint.Y() >= aIC.Y() ? GetBottom() : GetTop();
 542     }
 543     else
 544     {
 545         // x-coordinate
 546         if (rPoint.X() > GetItalicRight())
 547             aRef.X() = GetItalicRight();
 548         else if (rPoint.X() < GetItalicLeft())
 549             aRef.X() = GetItalicLeft();
 550         else
 551             aRef.X() = rPoint.X();
 552         // y-coordinate
 553         if (rPoint.Y() > GetBottom())
 554             aRef.Y() = GetBottom();
 555         else if (rPoint.Y() < GetTop())
 556             aRef.Y() = GetTop();
 557         else
 558             aRef.Y() = rPoint.Y();
 559     }
 560
 561     // build distance vector
 562     Point  aDist (aRef - rPoint);
 563
 564     long nAbsX = labs(aDist.X()),
 565          nAbsY = labs(aDist.Y());
 566
 567     return bIsInside ? - std::min(nAbsX, nAbsY) : std::max (nAbsX, nAbsY);
 568 }
 569
 570
 571 bool SmRect::IsInsideRect(const Point &rPoint) const
 572 {
 573     return     rPoint.Y() >= GetTop()
 574            &&  rPoint.Y() <= GetBottom()
 575            &&  rPoint.X() >= GetLeft()
 576            &&  rPoint.X() <= GetRight();
 577 }
 578
 579
 580 bool SmRect::IsInsideItalicRect(const Point &rPoint) const
 581 {
 582     return     rPoint.Y() >= GetTop()
 583            &&  rPoint.Y() <= GetBottom()
 584            &&  rPoint.X() >= GetItalicLeft()
 585            &&  rPoint.X() <= GetItalicRight();
 586 }
 587
 588 SmRect SmRect::AsGlyphRect() const
 589 {
 590     SmRect aRect (*this);
 591     aRect.SetTop(nGlyphTop);
 592     aRect.SetBottom(nGlyphBottom);
 593     return aRect;
 594 }
 595
 596 bool SmGetGlyphBoundRect(const vcl::RenderContext &rDev,
 597                          const OUString &rText, Rectangle &rRect)
 598     // basically the same as 'GetTextBoundRect' (in class 'OutputDevice')
 599     // but with a string as argument.
 600 {
 601     // handle special case first
 602     if (rText.isEmpty())
 603     {
 604         rRect.SetEmpty();
 605         return true;
 606     }
 607
 608     // get a device where 'OutputDevice::GetTextBoundRect' will be successful
 609     OutputDevice *pGlyphDev;
 610     if (rDev.GetOutDevType() != OUTDEV_PRINTER)
 611         pGlyphDev = const_cast<OutputDevice *>(&rDev);
 612     else
 613     {
 614         // since we format for the printer (where GetTextBoundRect will fail)
 615         // we need a virtual device here.
 616         pGlyphDev = &SM_MOD()->GetDefaultVirtualDev();
 617     }
 618
 619     const FontMetric  aDevFM (rDev.GetFontMetric());
 620
 621     pGlyphDev->Push(PushFlags::FONT | PushFlags::MAPMODE);
 622     vcl::Font aFnt(rDev.GetFont());
 623     aFnt.SetAlign(ALIGN_TOP);
 624
 625     // use scale factor when calling GetTextBoundRect to counter
 626     // negative effects from antialiasing which may otherwise result
 627     // in significant incorrect bounding rectangles for some characters.
 628     Size aFntSize = aFnt.GetSize();
 629
 630     // Workaround to avoid HUGE font sizes and resulting problems
 631     long nScaleFactor = 1;
 632     while( aFntSize.Height() > 2000 * nScaleFactor )
 633         nScaleFactor *= 2;
 634
 635     aFnt.SetSize( Size( aFntSize.Width() / nScaleFactor, aFntSize.Height() / nScaleFactor ) );
 636     pGlyphDev->SetFont(aFnt);
 637
 638     long nTextWidth = rDev.GetTextWidth(rText);
 639     Point aPoint;
 640     Rectangle   aResult (aPoint, Size(nTextWidth, rDev.GetTextHeight())),
 641                 aTmp;
 642
 643     bool bSuccess = pGlyphDev->GetTextBoundRect(aTmp, rText, 0, 0);
 644     OSL_ENSURE( bSuccess, "GetTextBoundRect failed" );
 645
 646
 647     if (!aTmp.IsEmpty())
 648     {
 649         aResult = Rectangle(aTmp.Left() * nScaleFactor, aTmp.Top() * nScaleFactor,
 650                             aTmp.Right() * nScaleFactor, aTmp.Bottom() * nScaleFactor);
 651         if (&rDev != pGlyphDev) /* only when rDev is a printer... */
 652         {
 653             long nGDTextWidth  = pGlyphDev->GetTextWidth(rText);
 654             if (nGDTextWidth != 0  &&
 655                 nTextWidth != nGDTextWidth)
 656             {
 657                 aResult.Right() *= nTextWidth;
 658                 aResult.Right() /= nGDTextWidth * nScaleFactor;
 659             }
 660         }
 661     }
 662
 663     // move rectangle to match possibly different baselines
 664     // (because of different devices)
 665     long nDelta = aDevFM.GetAscent() - pGlyphDev->GetFontMetric().GetAscent() * nScaleFactor;
 666     aResult.Move(0, nDelta);
 667
 668     pGlyphDev->Pop();
 669
 670     rRect = aResult;
 671     return bSuccess;
 672 }
 673
 674
 675 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */