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  ****************************************************************************/
  #include "qpaintengine.h"
  #include "qpaintengine_p.h"
  #include "qpainter_p.h"
  #include "qpolygon.h"
  #include "qbitmap.h"
  #include "qapplication.h"
  #include <qdebug.h>
  #include <qmath.h>
  #include <private/qtextengine_p.h>
  #include <qvarlengtharray.h>
  #include <private/qfontengine_p.h>
  #include <private/qpaintengineex_p.h>
  
  
  QT_BEGIN_NAMESPACE
  
  /*!
      \class QTextItem
  
      \brief The QTextItem class provides all the information required to draw
      text in a custom paint engine.
  
      When you reimplement your own paint engine, you must reimplement
      QPaintEngine::drawTextItem(), a function that takes a QTextItem as
      one of its arguments.
  */
  
  /*!
    \enum QTextItem::RenderFlag
  
    \value  RightToLeft Render the text from right to left.
    \value  Overline    Paint a line above the text.
    \value  Underline   Paint a line under the text.
    \value  StrikeOut   Paint a line through the text.
    \omitvalue Dummy
  */
  
  
  /*!
      \fn qreal QTextItem::descent() const
  
      Corresponds to the \l{QFontMetrics::descent()}{descent} of the piece of text that is drawn.
  */
  qreal QTextItem::descent() const
  {
      const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
      return ti->descent.toReal();
  }
  
  /*!
      \fn qreal QTextItem::ascent() const
  
      Corresponds to the \l{QFontMetrics::ascent()}{ascent} of the piece of text that is drawn.
  */
  qreal QTextItem::ascent() const
  {
      const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
      return ti->ascent.toReal();
  }
  
  /*!
      \fn qreal QTextItem::width() const
  
      Specifies the total width of the text to be drawn.
  */
  qreal QTextItem::width() const
  {
      const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
      return ti->width.toReal();
  }
  
  /*!
      \fn QTextItem::RenderFlags QTextItem::renderFlags() const
  
      Returns the render flags used.
  */
  QTextItem::RenderFlags QTextItem::renderFlags() const
  {
      const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
      return ti->flags;
  }
  
  /*!
      \fn QString QTextItem::text() const
  
      Returns the text that should be drawn.
  */
  QString QTextItem::text() const
  {
      const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
      return QString(ti->chars, ti->num_chars);
  }
  
  /*!
      \fn QFont QTextItem::font() const
  
      Returns the font that should be used to draw the text.
  */
  QFont QTextItem::font() const
  {
      const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
      return ti->f ? *ti->f : QApplication::font();
  }
  
  
  /*!
    \class QPaintEngine
    \ingroup painting
  
    \brief The QPaintEngine class provides an abstract definition of how
    QPainter draws to a given device on a given platform.
  
    Qt 4.0 provides several premade implementations of QPaintEngine for the
    different painter backends we support. We provide one paint engine for each
    window system and painting framework we support. This includes X11 on
    Unix/Linux and CoreGraphics on Mac OS X. In addition we provide QPaintEngine
    implementations for OpenGL (accessible through QGLWidget) and PostScript
    (accessible through QPSPrinter on X11). Additionally there is a raster-based
    paint engine that is a fallback for when an engine does not support a certain
    capability.
  
    If one wants to use QPainter to draw to a different backend,
    one must subclass QPaintEngine and reimplement all its virtual
    functions. The QPaintEngine implementation is then made available by
    subclassing QPaintDevice and reimplementing the virtual function
    QPaintDevice::paintEngine().
  
    QPaintEngine is created and owned by the QPaintDevice that created it.
  
    The big advantage of the QPaintEngine approach opposed to
    Qt 3's QPainter/QPaintDevice::cmd() approach is that it is now
    possible to adapt to multiple technologies on each platform and take
    advantage of each to the fullest.
  
    \sa QPainter, QPaintDevice::paintEngine(), {Paint System}
  */
  
  /*!
    \enum QPaintEngine::PaintEngineFeature
  
    This enum is used to describe the features or capabilities that the
    paint engine has. If a feature is not supported by the engine,
    QPainter will do a best effort to emulate that feature through other
    means and pass on an alpha blended QImage to the engine with the
    emulated results. Some features cannot be emulated: AlphaBlend and PorterDuff.
  
    \value AlphaBlend         The engine can alpha blend primitives.
    \value Antialiasing       The engine can use antialising to improve the appearance
                              of rendered primitives.
    \value BlendModes         The engine supports blending modes.
    \value BrushStroke        The engine supports drawing strokes that
                              contain brushes as fills, not just solid
                              colors (e.g. a dashed gradient line of
                              width 2).
    \value ConicalGradientFill The engine supports conical gradient fills.
    \value ConstantOpacity    The engine supports the feature provided by
                              QPainter::setOpacity().
    \value LinearGradientFill The engine supports linear gradient fills.
    \value MaskedBrush        The engine is capable of rendering brushes that has a
                              texture with an alpha channel or a mask.
    \value ObjectBoundingModeGradients The engine has native support for gradients
                              with coordinate mode QGradient::ObjectBoundingMode.
                              Otherwise, if QPaintEngine::PatternTransform is
                              supported, object bounding mode gradients are
                              converted to gradients with coordinate mode
                              QGradient::LogicalMode and a brush transform for
                              the coordinate mapping.
    \value PainterPaths       The engine has path support.
    \value PaintOutsidePaintEvent The engine is capable of painting outside of
                                  paint events.
    \value PatternBrush       The engine is capable of rendering brushes with
                              the brush patterns specified in Qt::BrushStyle.
    \value PatternTransform   The engine has support for transforming brush
                              patterns.
    \value PerspectiveTransform The engine has support for performing perspective
                              transformations on primitives.
    \value PixmapTransform    The engine can transform pixmaps, including
                              rotation and shearing.
    \value PorterDuff         The engine supports Porter-Duff operations
    \value PrimitiveTransform The engine has support for transforming
                              drawing primitives.
    \value RadialGradientFill The engine supports radial gradient fills.
    \value RasterOpModes      The engine supports bitwise raster operations.
    \value AllFeatures        All of the above features. This enum value is usually
                              used as a bit mask.
  */
  
  /*!
      \enum QPaintEngine::PolygonDrawMode
  
      \value OddEvenMode The polygon should be drawn using OddEven fill
      rule.
  
      \value WindingMode The polygon should be drawn using Winding fill rule.
  
      \value ConvexMode The polygon is a convex polygon and can be drawn
      using specialized algorithms where available.
  
      \value PolylineMode Only the outline of the polygon should be
      drawn.
  
  */
  
  /*!
      \enum QPaintEngine::DirtyFlag
  
      \value DirtyPen The pen is dirty and needs to be updated.
  
      \value DirtyBrush The brush is dirty and needs to be updated.
  
      \value DirtyBrushOrigin The brush origin is dirty and needs to
      updated.
  
      \value DirtyFont The font is dirty and needs to be updated.
  
      \value DirtyBackground The background is dirty and needs to be
      updated.
  
      \value DirtyBackgroundMode The background mode is dirty and needs
      to be updated.
  
      \value DirtyTransform The transform is dirty and needs to be
      updated.
  
      \value DirtyClipRegion The clip region is dirty and needs to be
      updated.
  
      \value DirtyClipPath The clip path is dirty and needs to be
      updated.
  
      \value DirtyHints The render hints is dirty and needs to be
      updated.
  
      \value DirtyCompositionMode The composition mode is dirty and
      needs to be updated.
  
      \value DirtyClipEnabled Whether clipping is enabled or not is
      dirty and needs to be updated.
  
      \value DirtyOpacity The constant opacity has changed and needs to
                          be updated as part of the state change in
                          QPaintEngine::updateState().
  
      \value AllDirty Convenience enum used internally.
  
      These types are used by QPainter to trigger lazy updates of the
      various states in the QPaintEngine using
      QPaintEngine::updateState().
  
      A paint engine must update every dirty state.
  */
  
  /*!
      \fn void QPaintEngine::syncState()
  
      \internal
  
      Updates all dirty states in this engine. This function should ONLY
      be used when drawing with native handles directly and immediate sync
      from QPainters state to the native state is required.
  */
  void QPaintEngine::syncState()
  {
      Q_ASSERT(state);
      updateState(*state);
  
      if (isExtended())
          static_cast<QPaintEngineEx *>(this)->sync();
  }
  
  static QPaintEngine *qt_polygon_recursion = 0;
  struct QT_Point {
      int x;
      int y;
  };
  
  /*!
      \fn void QPaintEngine::drawPolygon(const QPointF *points, int pointCount,
      PolygonDrawMode mode)
  
      Reimplement this virtual function to draw the polygon defined
      by the \a pointCount first points in \a points, using mode \a
      mode.
  
      \note At least one of the drawPolygon() functions must be reimplemented.
  */
  void QPaintEngine::drawPolygon(const QPointF *points, int pointCount, PolygonDrawMode mode)
  {
      Q_ASSERT_X(qt_polygon_recursion != this, "QPaintEngine::drawPolygon",
                 "At least one drawPolygon function must be implemented");
      qt_polygon_recursion = this;
      Q_ASSERT(sizeof(QT_Point) == sizeof(QPoint));
      QVarLengthArray<QT_Point> p(pointCount);
      for (int i = 0; i < pointCount; ++i) {
          p[i].x = qRound(points[i].x());
          p[i].y = qRound(points[i].y());
      }
      drawPolygon((QPoint *)p.data(), pointCount, mode);
      qt_polygon_recursion = 0;
  }
  
  struct QT_PointF {
      qreal x;
      qreal y;
  };
  /*!
      \overload
  
      Reimplement this virtual function to draw the polygon defined by the
      \a pointCount first points in \a points, using mode \a mode.
  
      \note At least one of the drawPolygon() functions must be reimplemented.
  */
  void QPaintEngine::drawPolygon(const QPoint *points, int pointCount, PolygonDrawMode mode)
  {
      Q_ASSERT_X(qt_polygon_recursion != this, "QPaintEngine::drawPolygon",
                 "At least one drawPolygon function must be implemented");
      qt_polygon_recursion = this;
      Q_ASSERT(sizeof(QT_PointF) == sizeof(QPointF));
      QVarLengthArray<QT_PointF> p(pointCount);
      for (int i=0; i<pointCount; ++i) {
          p[i].x = points[i].x();
          p[i].y = points[i].y();
      }
      drawPolygon((QPointF *)p.data(), pointCount, mode);
      qt_polygon_recursion = 0;
  }
  
  /*!
      \enum QPaintEngine::Type
  
      \value X11
      \value Windows
      \value MacPrinter
      \value CoreGraphics Mac OS X's Quartz2D (CoreGraphics)
      \value QuickDraw Mac OS X's QuickDraw
      \value QWindowSystem Qt for Embedded Linux
      \value PostScript
      \value OpenGL
      \value Picture QPicture format
      \value SVG Scalable Vector Graphics XML format
      \value Raster
      \value Direct3D Windows only, Direct3D based engine
      \value Pdf Portable Document Format
      \value OpenVG
      \value User First user type ID
      \value MaxUser Last user type ID
      \value OpenGL2
      \value PaintBuffer
      \value Blitter
  */
  
  /*!
      \fn bool QPaintEngine::isActive() const
  
      Returns true if the paint engine is actively drawing; otherwise
      returns false.
  
      \sa setActive()
  */
  
  /*!
      \fn void QPaintEngine::setActive(bool state)
  
      Sets the active state of the paint engine to \a state.
  
      \sa isActive()
  */
  
  /*!
      \fn bool QPaintEngine::begin(QPaintDevice *pdev)
  
      Reimplement this function to initialise your paint engine when
      painting is to start on the paint device \a pdev. Return true if
      the initialization was successful; otherwise return false.
  
      \sa end() isActive()
  */
  
  /*!
      \fn bool QPaintEngine::end()
  
      Reimplement this function to finish painting on the current paint
      device. Return true if painting was finished successfully;
      otherwise return false.
  
      \sa begin() isActive()
  */
  
  
  /*!
      Draws the first \a pointCount points in the buffer \a points
  */
  void QPaintEngine::drawPoints(const QPointF *points, int pointCount)
  {
      QPainter *p = painter();
      if (!p)
          return;
  
      qreal penWidth = p->pen().widthF();
      if (penWidth == 0)
          penWidth = 1;
  
      bool ellipses = p->pen().capStyle() == Qt::RoundCap;
  
      p->save();
  
      QTransform transform;
      if (p->pen().isCosmetic()) {
          transform = p->transform();
          p->setTransform(QTransform());
      }
  
      p->setBrush(p->pen().brush());
      p->setPen(Qt::NoPen);
  
      for (int i=0; i<pointCount; ++i) {
          QPointF pos = transform.map(points[i]);
          QRectF rect(pos.x() - penWidth / 2, pos.y() - penWidth / 2, penWidth, penWidth);
  
          if (ellipses)
              p->drawEllipse(rect);
          else
              p->drawRect(rect);
      }
  
      p->restore();
  }
  
  
  /*!
      Draws the first \a pointCount points in the buffer \a points
  
      The default implementation converts the first \a pointCount QPoints in \a points
      to QPointFs and calls the floating point version of drawPoints.
  
  */
  void QPaintEngine::drawPoints(const QPoint *points, int pointCount)
  {
      Q_ASSERT(sizeof(QT_PointF) == sizeof(QPointF));
      QT_PointF fp[256];
      while (pointCount) {
          int i = 0;
          while (i < pointCount && i < 256) {
              fp[i].x = points[i].x();
              fp[i].y = points[i].y();
              ++i;
          }
          drawPoints((QPointF *)(void *)fp, i);
          points += i;
          pointCount -= i;
      }
  }
  
  /*!
      \fn void QPaintEngine::drawEllipse(const QRectF &rect)
  
      Reimplement this function to draw the largest ellipse that can be
      contained within rectangle \a rect.
  
      The default implementation calls drawPolygon().
  */
  void QPaintEngine::drawEllipse(const QRectF &rect)
  {
      QPainterPath path;
      path.addEllipse(rect);
      if (hasFeature(PainterPaths)) {
          drawPath(path);
      } else {
          QPolygonF polygon = path.toFillPolygon();
          drawPolygon(polygon.data(), polygon.size(), ConvexMode);
      }
  }
  
  /*!
      The default implementation of this function calls the floating
      point version of this function
  */
  void QPaintEngine::drawEllipse(const QRect &rect)
  {
      drawEllipse(QRectF(rect));
  }
  
  /*!
      \fn void QPaintEngine::drawPixmap(const QRectF &r, const QPixmap
      &pm, const QRectF &sr)
  
      Reimplement this function to draw the part of the \a pm
      specified by the \a sr rectangle in the given \a r.
  */
  
  
  void qt_fill_tile(QPixmap *tile, const QPixmap &pixmap)
  {
      QPainter p(tile);
      p.drawPixmap(0, 0, pixmap);
      int x = pixmap.width();
      while (x < tile->width()) {
          p.drawPixmap(x, 0, *tile, 0, 0, x, pixmap.height());
          x *= 2;
      }
      int y = pixmap.height();
      while (y < tile->height()) {
          p.drawPixmap(0, y, *tile, 0, 0, tile->width(), y);
          y *= 2;
      }
  }
  
  void qt_draw_tile(QPaintEngine *gc, qreal x, qreal y, qreal w, qreal h,
                    const QPixmap &pixmap, qreal xOffset, qreal yOffset)
  {
      qreal yPos, xPos, drawH, drawW, yOff, xOff;
      yPos = y;
      yOff = yOffset;
      while(yPos < y + h) {
          drawH = pixmap.height() - yOff;    // Cropping first row
          if (yPos + drawH > y + h)           // Cropping last row
              drawH = y + h - yPos;
          xPos = x;
          xOff = xOffset;
          while(xPos < x + w) {
              drawW = pixmap.width() - xOff; // Cropping first column
              if (xPos + drawW > x + w)           // Cropping last column
                  drawW = x + w - xPos;
              if (drawW > 0 && drawH > 0)
                  gc->drawPixmap(QRectF(xPos, yPos, drawW, drawH), pixmap, QRectF(xOff, yOff, drawW, drawH));
              xPos += drawW;
              xOff = 0;
          }
          yPos += drawH;
          yOff = 0;
      }
  }
  
  
  /*!
      Reimplement this function to draw the \a pixmap in the given \a
      rect, starting at the given \a p. The pixmap will be
      drawn repeatedly until the \a rect is filled.
  */
  void QPaintEngine::drawTiledPixmap(const QRectF &rect, const QPixmap &pixmap, const QPointF &p)
  {
      int sw = pixmap.width();
      int sh = pixmap.height();
  
      if (sw*sh < 8192 && sw*sh < 16*rect.width()*rect.height()) {
          int tw = sw, th = sh;
          while (tw*th < 32678 && tw < rect.width()/2)
              tw *= 2;
          while (tw*th < 32678 && th < rect.height()/2)
              th *= 2;
          QPixmap tile;
          if (pixmap.depth() == 1) {
              tile = QBitmap(tw, th);
          } else {
              tile = QPixmap(tw, th);
              if (pixmap.hasAlphaChannel())
                  tile.fill(Qt::transparent);
          }
          qt_fill_tile(&tile, pixmap);
          qt_draw_tile(this, rect.x(), rect.y(), rect.width(), rect.height(), tile, p.x(), p.y());
      } else {
          qt_draw_tile(this, rect.x(), rect.y(), rect.width(), rect.height(), pixmap, p.x(), p.y());
      }
  }
  
  /*!
      \fn void QPaintEngine::drawImage(const QRectF &rectangle, const QImage
      &image, const QRectF &sr, Qt::ImageConversionFlags flags)
  
      Reimplement this function to draw the part of the \a image
      specified by the \a sr rectangle in the given \a rectangle using
      the given conversion flags \a flags, to convert it to a pixmap.
  */
  
  void QPaintEngine::drawImage(const QRectF &r, const QImage &image, const QRectF &sr,
                               Qt::ImageConversionFlags flags)
  {
      QRectF baseSize(0, 0, image.width(), image.height());
      QImage im = image;
      if (baseSize != sr)
          im = im.copy(qFloor(sr.x()), qFloor(sr.y()),
                       qCeil(sr.width()), qCeil(sr.height()));
      QPixmap pm = QPixmap::fromImage(im, flags);
      drawPixmap(r, pm, QRectF(QPointF(0, 0), pm.size()));
  }
  
  /*!
      \fn Type QPaintEngine::type() const
  
      Reimplement this function to return the paint engine \l{Type}.
  */
  
  /*!
      \fn void QPaintEngine::fix_neg_rect(int *x, int *y, int *w, int *h);
  
      \internal
  */
  
  /*!
      \fn bool QPaintEngine::testDirty(DirtyFlags df)
  
      \internal
  */
  
  /*!
      \fn void QPaintEngine::clearDirty(DirtyFlags df)
  
      \internal
  */
  
  /*!
      \fn void QPaintEngine::setDirty(DirtyFlags df)
  
      \internal
  */
  
  /*!
      \fn bool QPaintEngine::hasFeature(PaintEngineFeatures feature) const
  
      Returns true if the paint engine supports the specified \a
      feature; otherwise returns false.
  */
  
  /*!
      \fn bool QPaintEngine::isExtended() const
  
      \internal
  
      Returns true if the paint engine is a QPaintEngineEx derivative.
  */
  
  /*!
      \fn void QPaintEngine::updateState(const QPaintEngineState &state)
  
      Reimplement this function to update the state of a paint engine.
  
      When implemented, this function is responsible for checking the
      paint engine's current \a state and update the properties that are
      changed. Use the QPaintEngineState::state() function to find out
      which properties that must be updated, then use the corresponding
      \l {GetFunction}{get function} to retrieve the current values for
      the given properties.
  
      \sa QPaintEngineState
  */
  
  /*!
      Creates a paint engine with the featureset specified by \a caps.
  */
  
  QPaintEngine::QPaintEngine(PaintEngineFeatures caps)
      : state(0),
        gccaps(caps),
        active(0),
        selfDestruct(false),
        extended(false),
        d_ptr(new QPaintEnginePrivate)
  {
      d_ptr->q_ptr = this;
  }
  
  /*!
    \internal
  */
  
  QPaintEngine::QPaintEngine(QPaintEnginePrivate &dptr, PaintEngineFeatures caps)
      : state(0),
        gccaps(caps),
        active(0),
        selfDestruct(false),
        extended(false),
        d_ptr(&dptr)
  {
      d_ptr->q_ptr = this;
  }
  
  /*!
      Destroys the paint engine.
  */
  QPaintEngine::~QPaintEngine()
  {
  }
  
  /*!
      Returns the paint engine's painter.
  */
  QPainter *QPaintEngine::painter() const
  {
      return state ? state->painter() : 0;
  }
  
  /*!
      The default implementation ignores the \a path and does nothing.
  */
  
  void QPaintEngine::drawPath(const QPainterPath &)
  {
      if (hasFeature(PainterPaths)) {
          qWarning("QPaintEngine::drawPath: Must be implemented when feature PainterPaths is set");
      }
  }
  
  /*!
      This function draws the text item \a textItem at position \a p. The
      default implementation of this function converts the text to a
      QPainterPath and paints the resulting path.
  */
  
  void QPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem)
  {
      const QTextItemInt &ti = static_cast<const QTextItemInt &>(textItem);
  
      QPainterPath path;
  #ifndef Q_WS_MAC
      path.setFillRule(Qt::WindingFill);
  #endif
      if (ti.glyphs.numGlyphs)
          ti.fontEngine->addOutlineToPath(0, 0, ti.glyphs, &path, ti.flags);
      if (!path.isEmpty()) {
          painter()->save();
          painter()->setRenderHint(QPainter::Antialiasing,
                                   bool((painter()->renderHints() & QPainter::TextAntialiasing)
                                        && !(painter()->font().styleStrategy() & QFont::NoAntialias)));
          painter()->translate(p.x(), p.y());
          painter()->fillPath(path, state->pen().brush());
          painter()->restore();
      }
  }
  
  /*!
      The default implementation splits the list of lines in \a lines
      into \a lineCount separate calls to drawPath() or drawPolygon()
      depending on the feature set of the paint engine.
  */
  void QPaintEngine::drawLines(const QLineF *lines, int lineCount)
  {
      for (int i=0; i<lineCount; ++i) {
          QPointF pts[2] = { lines[i].p1(), lines[i].p2() };
  
          if (pts[0] == pts[1]) {
              if (state->pen().capStyle() != Qt::FlatCap)
                  drawPoints(pts, 1);
              continue;
          }
  
          drawPolygon(pts, 2, PolylineMode);
      }
  }
  
  /*!
      \overload
  
      The default implementation converts the first \a lineCount lines
      in \a lines to a QLineF and calls the floating point version of
      this function.
  */
  void QPaintEngine::drawLines(const QLine *lines, int lineCount)
  {
      struct PointF {
          qreal x;
          qreal y;
      };
      struct LineF {
          PointF p1;
          PointF p2;
      };
      Q_ASSERT(sizeof(PointF) == sizeof(QPointF));
      Q_ASSERT(sizeof(LineF) == sizeof(QLineF));
      LineF fl[256];
      while (lineCount) {
          int i = 0;
          while (i < lineCount && i < 256) {
              fl[i].p1.x = lines[i].x1();
              fl[i].p1.y = lines[i].y1();
              fl[i].p2.x = lines[i].x2();
              fl[i].p2.y = lines[i].y2();
              ++i;
          }
          drawLines((QLineF *)(void *)fl, i);
          lines += i;
          lineCount -= i;
      }
  }
  
  
  /*!
      \overload
  
      The default implementation converts the first \a rectCount
      rectangles in the buffer \a rects to a QRectF and calls the
      floating point version of this function.
  */
  void QPaintEngine::drawRects(const QRect *rects, int rectCount)
  {
      struct RectF {
          qreal x;
          qreal y;
          qreal w;
          qreal h;
      };
      Q_ASSERT(sizeof(RectF) == sizeof(QRectF));
      RectF fr[256];
      while (rectCount) {
          int i = 0;
          while (i < rectCount && i < 256) {
              fr[i].x = rects[i].x();
              fr[i].y = rects[i].y();
              fr[i].w = rects[i].width();
              fr[i].h = rects[i].height();
              ++i;
          }
          drawRects((QRectF *)(void *)fr, i);
          rects += i;
          rectCount -= i;
      }
  }
  
  /*!
      Draws the first \a rectCount rectangles in the buffer \a
      rects. The default implementation of this function calls drawPath()
      or drawPolygon() depending on the feature set of the paint engine.
  */
  void QPaintEngine::drawRects(const QRectF *rects, int rectCount)
  {
      if (hasFeature(PainterPaths) &&
          !state->penNeedsResolving() &&
          !state->brushNeedsResolving()) {
          for (int i=0; i<rectCount; ++i) {
              QPainterPath path;
              path.addRect(rects[i]);
              if (path.isEmpty())
                  continue;
              drawPath(path);
          }
      } else {
          for (int i=0; i<rectCount; ++i) {
              QRectF rf = rects[i];
              QPointF pts[4] = { QPointF(rf.x(), rf.y()),
                                 QPointF(rf.x() + rf.width(), rf.y()),
                                 QPointF(rf.x() + rf.width(), rf.y() + rf.height()),
                                 QPointF(rf.x(), rf.y() + rf.height()) };
              drawPolygon(pts, 4, ConvexMode);
          }
      }
  }
  
  /*!
      \internal
      Sets the paintdevice that this engine operates on to \a device
  */
  void QPaintEngine::setPaintDevice(QPaintDevice *device)
  {
      d_func()->pdev = device;
  }
  
  /*!
      Returns the device that this engine is painting on, if painting is
      active; otherwise returns 0.
  */
  QPaintDevice *QPaintEngine::paintDevice() const
  {
      return d_func()->pdev;
  }
  
  #ifdef Q_WS_WIN
  /*!
      \internal
  
      Empty default implementation.
  */
  
  HDC QPaintEngine::getDC() const
  {
      return 0;
  }
  
  
  /*!
      \internal
  
      Empty default implementation.
  */
  
  void QPaintEngine::releaseDC(HDC) const
  {
  }
  
  #endif
  
  /*!
      \internal
  
      Returns the offset from the painters origo to the engines
      origo. This value is used by QPainter for engines who have
      internal double buffering.
  
      This function only makes sense when the engine is active.
  */
  QPoint QPaintEngine::coordinateOffset() const
  {
      return QPoint();
  }
  
  /*!
      \internal
  
      Sets the system clip for this engine. The system clip defines the
      basis area that the engine has to draw in. All clips that are
      set will be be an intersection with the system clip.
  
      Reset the systemclip to no clip by setting an empty region.
  */
  void QPaintEngine::setSystemClip(const QRegion &region)
  {
      Q_D(QPaintEngine);
      d->systemClip = region;
      // Be backward compatible and only call d->systemStateChanged()
      // if we currently have a system transform/viewport set.
      if (d->hasSystemTransform || d->hasSystemViewport) {
          d->transformSystemClip();
          d->systemStateChanged();
      }
  }
  
  /*!
      \internal
  
      Returns the system clip. The system clip is read only while the
      painter is active. An empty region indicates that system clip
      is not in use.
  */
  
  QRegion QPaintEngine::systemClip() const
  {
      return d_func()->systemClip;
  }
  
  /*!
      \internal
  
      Sets the target rect for drawing within the backing store. This
      function should ONLY be used by the backing store.
  */
  void QPaintEngine::setSystemRect(const QRect &rect)
  {
      if (isActive()) {
          qWarning("QPaintEngine::setSystemRect: Should not be changed while engine is active");
          return;
      }
      d_func()->systemRect = rect;
  }
  
  /*!
      \internal
  
      Retrieves the rect for drawing within the backing store. This
      function should ONLY be used by the backing store.
   */
  QRect QPaintEngine::systemRect() const
  {
      return d_func()->systemRect;
  }
  
  void QPaintEnginePrivate::drawBoxTextItem(const QPointF &p, const QTextItemInt &ti)
  {
      if (!ti.glyphs.numGlyphs)
          return;
  
      // any fixes here should probably also be done in QFontEngineBox::draw
      const int size = qRound(ti.fontEngine->ascent());
      QVarLengthArray<QFixedPoint> positions;
      QVarLengthArray<glyph_t> glyphs;
      QTransform matrix = QTransform::fromTranslate(p.x(), p.y() - size);
      ti.fontEngine->getGlyphPositions(ti.glyphs, matrix, ti.flags, glyphs, positions);
      if (glyphs.size() == 0)
          return;
  
      QSize s(size - 3, size - 3);
  
      QPainter *painter = q_func()->state->painter();
      painter->save();
      painter->setBrush(Qt::NoBrush);
      QPen pen = painter->pen();
      pen.setWidthF(ti.fontEngine->lineThickness().toReal());
      painter->setPen(pen);
      for (int k = 0; k < positions.size(); k++)
          painter->drawRect(QRectF(positions[k].toPointF(), s));
      painter->restore();
  }
  
  QT_END_NAMESPACE
  