qpaintengine.cpp

奇趣公司比较新的qt/emd版本

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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 <private/qtextengine_p.h>
#include <private/qmath_p.h>
#include <qvarlengtharray.h>

/*!
    \class QTextItem
    \internal
*/

qreal QTextItem::descent() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->descent.toReal();
}

qreal QTextItem::ascent() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->ascent.toReal();
}

qreal QTextItem::width() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->width.toReal();
}

QTextItem::RenderFlags QTextItem::renderFlags() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->flags;
}

QString QTextItem::text() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return QString(ti->chars, ti->num_chars);
}

QFont QTextItem::font() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->f ? *ti->f : QApplication::font();
}


#include <private/qfontengine_p.h>

/*!
  \class QPaintEngine
  \ingroup multimedia

  \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(), {The 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 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 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.
*/

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.

    The default implementation of this function will try to use drawPath
    if the engine supports the feature QPaintEngine::PainterPaths or try
    the float based drawPolygon() implementation if not.
*/
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.

    The default implementation of this function will try to use drawPath()
    if the engine supports the feature QPaintEngine::PainterPaths or try
    the int based drawPolygon() implementation if not.
*/
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 Qtopia Core
    \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 User First user type ID
    \value MaxUser Last user type ID
*/

/*!
    \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)
{
    for (int i=0; i<pointCount; ++i) {
        QLineF line(points[i].x(), points[i].y(), points[i].x(), points[i].y() + 0.001);
        drawLines(&line, 1);
    }
}


/*!
    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()) {