QPainterPath Class Reference

#include <qpainterpath.h>

Collaboration diagram for QPainterPath:

[legend]List of all members.

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Detailed Description

The QPainterPath class provides a container for painting operations, enabling graphical shapes to be constructed and reused.

A painter path is an object composed of a number of graphical building blocks, such as rectangles, ellipses, lines, and curves. Building blocks can be joined in closed subpaths, for example as a rectangle or an ellipse. A closed path has coinciding start and end points. Or they can exist independently as unclosed subpaths, such as lines and curves.

A QPainterPath object can be used for filling, outlining, and clipping. To generate fillable outlines for a given painter path, use the QPainterPathStroker class. The main advantage of painter paths over normal drawing operations is that complex shapes only need to be created once; then they can be drawn many times using only calls to the QPainter::drawPath() function.

QPainterPath provides a collection of functions that can be used to obtain information about the path and its elements. In addition it is possible to reverse the order of the elements using the toReversed() function. There are also several functions to convert this painter path object into a polygon representation.

A QPainterPath object can be constructed as an empty path, with a given start point, or as a copy of another QPainterPath object. Once created, lines and curves can be added to the path using the lineTo(), arcTo(), cubicTo() and quadTo() functions. The lines and curves stretch from the currentPosition() to the position passed as argument. The currentPosition() of the QPainterPath object is always the end position of the last subpath that was added (or the initial start point). Use the moveTo() function to move the currentPosition() without adding a component. The moveTo() function implicitly starts a new subpath, and closes the previous one. Another way of starting a new subpath is to call the closeSubpath() function which closes the current path by adding a line from the currentPosition() back to the path's start position. Note that the new path will have (0, 0) as its initial currentPosition(). QPainterPath class also provides several convenience functions to add closed subpaths to a painter path: addEllipse(), addPath(), addRect(), addRegion() and addText(). The addPolygon() function adds an \e unclosed subpath. In fact, these functions are all collections of moveTo(), lineTo() and cubicTo() operations. In addition, a path can be added to the current path using the connectPath() function. But note that this function will connect the last element of the current path to the first element of given one by adding a line. Below is a code snippet that shows how a QPainterPath object can be used: \table 100% \row \o \inlineimage qpainterpath-construction.png \o @code QPainterPath path; path.addRect(20, 20, 60, 60); path.moveTo(0, 0); path.cubicTo(99, 0, 50, 50, 99, 99); path.cubicTo(0, 99, 50, 50, 0, 0); QPainter painter(this); painter.fillRect(0, 0, 100, 100, Qt::white); painter.setPen(QPen(QColor(79, 106, 25), 1, Qt::SolidLine, Qt::FlatCap, Qt::MiterJoin)); painter.setBrush(QColor(122, 163, 39)); painter.drawPath(path); \endcode \endtable The painter path is initially empty when constructed. We first add a rectangle, which is a closed subpath. Then we add two bezier curves which together form a closed subpath even though they are not closed individually. Finally we draw the entire path. The path is filled using the default fill rule, Qt::OddEvenFill. Qt provides two methods for filling paths: \table \row \o \inlineimage qt-fillrule-oddeven.png \o \inlineimage qt-fillrule-winding.png \header \o Qt::OddEvenFill \o Qt::WindingFill \endtable See the Qt::Fillrule documentation for the definition of the rules. A painter path's currently set fill rule can be retrieved using the fillRule() function, and altered using the setFillRule() function. @section QPainterPath Information The QPainterPath class provides a collection of functions that returns information about the path and its elements. The currentPosition() function returns the end point of the last subpath that was added (or the initial start point). The elementAt() function can be used to retrieve the various subpath elements, the \e number of elements can be retrieved using the elementCount() function, and the isEmpty() function tells whether this QPainterPath object contains any elements at all. The controlPointRect() function returns the rectangle containing all the points and control points in this path. This function is significantly faster to compute than the exact boundingRect() which returns the bounding rectangle of this painter path with floating point precision. Finally, QPainterPath provides the contains() function which can be used to determine whether a given point or rectangle is inside the path, and the intersects() function which determines if any of the points inside a given rectangle also are inside this path. @section QPainterPath Conversion For compatibility reasons, it might be required to simplify the representation of a painter path: QPainterPath provides the toFillPolygon(), toFillPolygons() and toSubpathPolygons() functions which convert the painter path into a polygon. The toFillPolygon() returns the painter path as one single polygon, while the two latter functions return a list of polygons. The toFillPolygons() and toSubpathPolygons() functions are provided because it is usually faster to draw several small polygons than to draw one large polygon, even though the total number of points drawn is the same. The difference between the two is the \e number of polygons they return: The toSubpathPolygons() creates one polygon for each subpath regardless of intersecting subpaths (i.e. overlapping bounding rectangles), while the toFillPolygons() functions creates only one polygon for overlapping subpaths. The toFillPolygon() and toFillPolygons() functions first convert all the subpaths to polygons, then uses a rewinding technique to make sure that overlapping subpaths can be filled using the correct fill rule. Note that rewinding inserts additional lines in the polygon so the outline of the fill polygon does not match the outline of the path. @section Examples Qt provides the \l {painting/painterpaths}{Painter Paths Example} and the \l {demos/deform}{Vector Deformation Demo} which are located in Qt's example and demo directories respectively. The \l {painting/painterpaths}{Painter Paths Example} shows how painter paths can be used to build complex shapes for rendering and lets the user experiment with the filling and stroking. The \l {demos/deform}{Vector Deformation Demo} shows how to use QPainterPath to draw text. \table \row \o \inlineimage qpainterpath-example.png \o \inlineimage qpainterpath-demo.png \header \o \l {painting/painterpaths}{Painter Paths Example} \o \l {demos/deform}{Vector Deformation Demo} \endtable \sa QPainterPathStroker, QPainter, QRegion, {Painter Paths Example} Definition at line 44 of file qpainterpath.h.

Public Types
enum	ElementType
Public Member Functions
	QPainterPath ()
	QPainterPath (const QPointF &startPoint)
	QPainterPath (const QPainterPath &other)
QPainterPath &	operator= (const QPainterPath &other)
	~QPainterPath ()
void	closeSubpath ()
void	moveTo (const QPointF &p)
void	moveTo (qreal x, qreal y)
void	lineTo (const QPointF &p)
void	lineTo (qreal x, qreal y)
void	arcMoveTo (const QRectF &rect, qreal angle)
void	arcMoveTo (qreal x, qreal y, qreal w, qreal h, qreal angle)
void	arcTo (const QRectF &rect, qreal startAngle, qreal arcLength)
void	arcTo (qreal x, qreal y, qreal w, qreal h, qreal startAngle, qreal arcLength)
void	cubicTo (const QPointF &ctrlPt1, const QPointF &ctrlPt2, const QPointF &endPt)
void	cubicTo (qreal ctrlPt1x, qreal ctrlPt1y, qreal ctrlPt2x, qreal ctrlPt2y, qreal endPtx, qreal endPty)
void	quadTo (const QPointF &ctrlPt, const QPointF &endPt)
void	quadTo (qreal ctrlPtx, qreal ctrlPty, qreal endPtx, qreal endPty)
QPointF	currentPosition () const
void	addRect (const QRectF &rect)
void	addRect (qreal x, qreal y, qreal w, qreal h)
void	addEllipse (const QRectF &rect)
void	addEllipse (qreal x, qreal y, qreal w, qreal h)
void	addPolygon (const QPolygonF &polygon)
void	addText (const QPointF &point, const QFont &f, const QString &text)
void	addText (qreal x, qreal y, const QFont &f, const QString &text)
void	addPath (const QPainterPath &path)
void	addRegion (const QRegion &region)
void	connectPath (const QPainterPath &path)
bool	contains (const QPointF &pt) const
bool	contains (const QRectF &rect) const
bool	intersects (const QRectF &rect) const
QRectF	boundingRect () const
QRectF	controlPointRect () const
Qt::FillRule	fillRule () const
void	setFillRule (Qt::FillRule fillRule)
bool	isEmpty () const
QPainterPath	toReversed () const
QList< QPolygonF >	toSubpathPolygons (const QMatrix &matrix=QMatrix()) const
QList< QPolygonF >	toFillPolygons (const QMatrix &matrix=QMatrix()) const
QPolygonF	toFillPolygon (const QMatrix &matrix=QMatrix()) const
int	elementCount () const
const QPainterPath::Element &	elementAt (int i) const
void	setElementPositionAt (int i, qreal x, qreal y)
bool	operator== (const QPainterPath &other) const
bool	operator!= (const QPainterPath &other) const
Private Member Functions
void	ensureData ()
void	ensureData_helper ()
void	detach ()
void	detach_helper ()
QPainterPathData *	d_func () const
Private Attributes
QPainterPathPrivate *	d_ptr
Friends
class	QPainterPathData
class	QPainterPathStroker
class	QPainterPathStrokerPrivate
class	QMatrix
Q_GUI_EXPORT QDataStream &	operator<< (QDataStream &, const QPainterPath &)
Q_GUI_EXPORT QDataStream &	operator>> (QDataStream &, QPainterPath &)
Classes
class	Element
	The QPainterPath::Element class specifies the position and type of a subpath. More...

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Member Enumeration Documentation

enum QPainterPath::ElementType

This enum describes the types of elements used to connect vertices in subpaths.

Note that elements added as closed subpaths using the addEllipse(), addPath(), addPolygon(), addRect(), addRegion() and addText() convenience functions, is actually added to the path as a collection of separate elements using the moveTo(), lineTo() and cubicTo() functions.

MoveToElement A new subpath. See also moveTo(). LineToElement A line. See also lineTo(). CurveToElement A curve. See also cubicTo() and quadTo(). CurveToDataElement The extra data required to describe a curve in a CurveToElement element.

See also:

elementAt(), elementCount()

Definition at line 47 of file qpainterpath.h.

                     {
        MoveToElement,
        LineToElement,
        CurveToElement,
        CurveToDataElement
    };

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Constructor & Destructor Documentation

QPainterPath::QPainterPath

(

)

Constructs an empty QPainterPath object.

Definition at line 462 of file qpainterpath.cpp.

    : d_ptr(0)
{
}

QPainterPath::QPainterPath

(

const QPointF &

startPoint

)

[explicit]

Creates a QPainterPath object with the given startPoint as its current position.

Definition at line 486 of file qpainterpath.cpp.

References d_func(), MoveToElement, QPointF::x(), and QPointF::y().

    : d_ptr(new QPainterPathData)
{
    Element e = { startPoint.x(), startPoint.y(), MoveToElement };
    d_func()->elements << e;
}

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QPainterPath::QPainterPath

(

const QPainterPath &

path

)

Creates a QPainterPath object that is a copy of the given path.

See also:

operator=()

Definition at line 474 of file qpainterpath.cpp.

References d_func().

    : d_ptr(other.d_ptr)
{
    if (d_func())
        d_func()->ref.ref();
}

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QPainterPath::~QPainterPath

(

)

Destroys this QPainterPath object.

Definition at line 541 of file qpainterpath.cpp.

References d_func().

{
    if (d_func() && !d_func()->ref.deref())
        delete d_func();
}

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Member Function Documentation

QPainterPath & QPainterPath::operator=

(

const QPainterPath &

path

)

Assigns the given path to this painter path.

See also:

QPainterPath()

Definition at line 526 of file qpainterpath.cpp.

References d_func(), d_ptr, data, and qAtomicSetPtr().

{
    if (other.d_func() != d_func()) {
        QPainterPathPrivate *data = other.d_func();
        if (data) data->ref.ref();
        data = qAtomicSetPtr(&d_ptr, data);
        if (data && !data->ref.deref())
            delete (QPainterPathData *) data;
    }
    return *this;
}

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void QPainterPath::closeSubpath

(

)

Closes the current subpath by drawing a line to the beginning of the subpath, automatically starting a new path. The current point of the new path is (0, 0).

If the subpath does not contain any elements, this function does nothing.

See also:

moveTo(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 558 of file qpainterpath.cpp.

References QPainterPathData::close(), d_func(), detach(), isEmpty(), and printf.

Referenced by QPainter::drawConvexPolygon(), QPainter::drawPolygon(), PieView::itemRegion(), ArthurFrame::paintEvent(), Launcher::showCategories(), and Launcher::showExamples().

{
#ifdef QPP_DEBUG
    printf("QPainterPath::closeSubpath()\n");
#endif
    if (isEmpty())
        return;
    detach();

    d_func()->close();
}

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void QPainterPath::moveTo

(

const QPointF &

point

)

Moves the current point to the given point, implicitly starting a new subpath and closing the previous one.

See also:

closeSubpath(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 588 of file qpainterpath.cpp.

References d, d_func(), detach(), ensureData(), MoveToElement, p, printf, qIsNan(), and qWarning().

Referenced by addEllipse(), addPolygon(), addRect(), arcMoveTo(), QPainter::drawLines(), ArthurStyle::drawPrimitive(), PieView::itemRegion(), moveTo(), RenderArea::paintEvent(), ArthurFrame::paintEvent(), Window::setupShapes(), Launcher::showCategories(), Launcher::showExamples(), SortingBox::SortingBox(), and toReversed().

{
#ifdef QPP_DEBUG
    printf("QPainterPath::moveTo() (%.2f,%.2f)\n", p.x(), p.y());
#endif
#ifndef QT_NO_DEBUG
    if (qIsNan(p.x()) || qIsNan(p.y()))
        qWarning("QPainterPath::moveTo: Adding point where x or y is NaN, results are undefined");
#endif
    ensureData();
    detach();

    QPainterPathData *d = d_func();
    Q_ASSERT(!d->elements.isEmpty());

    d->require_moveTo = false;

    if (d->elements.last().type == MoveToElement) {
        d->elements.last().x = p.x();
        d->elements.last().y = p.y();
    } else {
        Element elm = { p.x(), p.y(), MoveToElement };
        d->elements.append(elm);
    }
    d->cStart = d->elements.size() - 1;
}

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void QPainterPath::moveTo	(	qreal	x,
		qreal	y
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Moves the current position to ({x}, {y}) and starts a new subpath, implicitly closing the previous path.

Definition at line 211 of file qpainterpath.h.

References moveTo().

{
    moveTo(QPointF(x, y));
}

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void QPainterPath::lineTo

(

const QPointF &

endPoint

)

Adds a straight line from the current position to the given endPoint. After the line is drawn, the current position is updated to be at the end point of the line.

See also:

addPolygon(), addRect(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 634 of file qpainterpath.cpp.

References d, d_func(), detach(), ensureData(), LineToElement, p, printf, qIsNan(), and qWarning().

Referenced by arcTo(), QPlastiqueStyle::drawControl(), QPainter::drawConvexPolygon(), QPainter::drawLines(), QPainter::drawPolygon(), QPainter::drawPolyline(), lineTo(), VersionLabel::mouseMoveEvent(), VersionLabel::mouseReleaseEvent(), RenderArea::paintEvent(), Window::setupShapes(), Launcher::showCategories(), Launcher::showExamples(), SortingBox::SortingBox(), and toReversed().

{
#ifdef QPP_DEBUG
    printf("QPainterPath::lineTo() (%.2f,%.2f)\n", p.x(), p.y());
#endif
#ifndef QT_NO_DEBUG
    if (qIsNan(p.x()) || qIsNan(p.y()))
        qWarning("QPainterPath::lineTo: Adding point where x or y is NaN, results are undefined");
#endif
    ensureData();
    detach();

    QPainterPathData *d = d_func();
    Q_ASSERT(!d->elements.isEmpty());
    d->maybeMoveTo();
    if (p == QPointF(d->elements.last()))
        return;
    Element elm = { p.x(), p.y(), LineToElement };
    d->elements.append(elm);
}

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void QPainterPath::lineTo	(	qreal	x,
		qreal	y
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Draws a line from the current position to the point ({x}, {y}).

Definition at line 216 of file qpainterpath.h.

References lineTo().

{
    lineTo(QPointF(x, y));
}

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void QPainterPath::arcMoveTo	(	const QRectF &	rectangle,
		qreal	angle
	)

Since:

4.2

Creates a move to that lies on the arc that occupies the given rectangle at angle.

Angles are specified in degrees. Clockwise arcs can be specified using negative angles.

See also:

moveTo(), arcTo()

Definition at line 886 of file qpainterpath.cpp.

References QRectF::isNull(), moveTo(), and qt_find_ellipse_coords().

Referenced by arcMoveTo().

{
    if (rect.isNull())
        return;

    QPointF pt;
    qt_find_ellipse_coords(rect, angle, 0, &pt, 0);
    moveTo(pt);
}

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void QPainterPath::arcMoveTo	(	qreal	x,
		qreal	y,
		qreal	width,
		qreal	height,
		qreal	angle
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since:

4.2

Creates a move to that lies on the arc that occupies the QRectF(x, y, width, height) at angle.

Definition at line 226 of file qpainterpath.h.

References arcMoveTo().

{
    arcMoveTo(QRectF(x, y, w, h), angle);
}

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void QPainterPath::arcTo	(	const QRectF &	rectangle,
		qreal	startAngle,
		qreal	sweepLength
	)

Creates an arc that occupies the given rectangle, beginning at the specified startAngle and extending sweepLength degrees counter-clockwise.

Angles are specified in degrees. Clockwise arcs can be specified using negative angles.

Note that this function connects the starting point of the arc to the current position if they are not already connected. After the arc has been added, the current position is the last point in arc. To draw a line back to the first point, use the closeSubpath() function.

100% qpainterpath-arcto.png

        QLinearGradient myGradient;
        QPen myPen;

        QPointF center, startPoint;

        QPainterPath myPath;
        myPath.moveTo(center);
        myPath.arcTo(boundingRect, startAngle,
                     sweepLength);

        QPainter painter(this);
        painter.setBrush(myGradient);
        painter.setPen(myPen);
        painter.drawPath(myPath);

See also:

arcMoveTo(), addEllipse(), QPainter::drawArc(), QPainter::drawPie(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 832 of file qpainterpath.cpp.

References cubicTo(), detach(), ensureData(), QRectF::height(), i, QRectF::isNull(), lineTo(), printf, qIsNan(), qt_curves_for_arc(), qWarning(), QRectF::width(), QRectF::x(), x, QRectF::y(), and y.

Referenced by arcTo(), ArthurStyle::drawPrimitive(), PieView::itemRegion(), and ArthurFrame::paintEvent().

{
#ifdef QPP_DEBUG
    printf("QPainterPath::arcTo() (%.2f, %.2f, %.2f, %.2f, angle=%.2f, sweep=%.2f\n",
           rect.x(), rect.y(), rect.width(), rect.height(), startAngle, sweepLength);
#endif
#ifndef QT_NO_DEBUG
    if (qIsNan(rect.x()) || qIsNan(rect.y()) || qIsNan(rect.width()) || qIsNan(rect.height())
        || qIsNan(startAngle) || qIsNan(sweepLength))
        qWarning("QPainterPath::arcTo: Adding arc where a parameter is NaN, results are undefined");
#endif
    if (rect.isNull())
        return;

    ensureData();
    detach();

    int point_count;
    QPointF pts[12];
    QPointF curve_start = qt_curves_for_arc(rect, startAngle, sweepLength, pts, &point_count);

    lineTo(curve_start);
    for (int i=0; i<point_count; i+=3) {
        cubicTo(pts[i].x(), pts[i].y(),
                pts[i+1].x(), pts[i+1].y(),
                pts[i+2].x(), pts[i+2].y());
    }

}

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void QPainterPath::arcTo	(	qreal	x,
		qreal	y,
		qreal	width,
		qreal	height,
		qreal	startAngle,
		qreal	sweepLength
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Creates an arc that occupies the rectangle QRectF(x, y, width, height), beginning at the specified startAngle and extending sweepLength degrees counter-clockwise.

Definition at line 221 of file qpainterpath.h.

References arcTo().

{
    arcTo(QRectF(x, y, w, h), startAngle, arcLenght);
}

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void QPainterPath::cubicTo	(	const QPointF &	c1,
		const QPointF &	c2,
		const QPointF &	endPoint
	)

Adds a cubic Bezier curve between the current position and the given endPoint using the control points specified by c1, and c2.

After the curve is added, the current position is updated to be at the end point of the curve.

100% qpainterpath-cubicto.png

        QLinearGradient myGradient;
        QPen myPen;

        QPainterPath myPath;
        myPath.cubicto(c1, c2, endPoint);

        QPainter painter(this);
        painter.setBrush(myGradient);
        painter.setPen(myPen);
        painter.drawPath(myPath);

See also:

quadTo(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 697 of file qpainterpath.cpp.

References CurveToDataElement, CurveToElement, d, d_func(), detach(), ensureData(), printf, qIsNan(), qWarning(), QPointF::x(), and QPointF::y().

Referenced by addEllipse(), arcTo(), cubicTo(), RenderArea::paintEvent(), quadTo(), and toReversed().

{
#ifdef QPP_DEBUG
    printf("QPainterPath::cubicTo() (%.2f,%.2f), (%.2f,%.2f), (%.2f,%.2f)\n",
           c1.x(), c1.y(), c2.x(), c2.y(), e.x(), e.y());
#endif
#ifndef QT_NO_DEBUG
    if (qIsNan(c1.x()) || qIsNan(c1.y()) || qIsNan(c2.x()) || qIsNan(c2.y())
        || qIsNan(e.x()) || qIsNan(e.y()))
        qWarning("QPainterPath::cubicTo: Adding point where x or y is NaN, results are undefined");
#endif
    ensureData();
    detach();

    QPainterPathData *d = d_func();
    Q_ASSERT(!d->elements.isEmpty());


    // Abort on empty curve as a stroker cannot handle this and the
    // curve is irrelevant anyway.
    if (d->elements.last() == c1 && c1 == c2 && c2 == e)
        return;

    d->maybeMoveTo();

    Element ce1 = { c1.x(), c1.y(), CurveToElement };
    Element ce2 = { c2.x(), c2.y(), CurveToDataElement };
    Element ee = { e.x(), e.y(), CurveToDataElement };
    d->elements << ce1 << ce2 << ee;
}

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void QPainterPath::cubicTo	(	qreal	c1X,
		qreal	c1Y,
		qreal	c2X,
		qreal	c2Y,
		qreal	endPointX,
		qreal	endPointY
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Adds a cubic Bezier curve between the current position and the end point ({endPointX}, {endPointY}) with control points specified by ({c1X}, {c1Y}) and ({c2X}, {c2Y}).

Definition at line 231 of file qpainterpath.h.

References cubicTo().

{
    cubicTo(QPointF(ctrlPt1x, ctrlPt1y), QPointF(ctrlPt2x, ctrlPt2y),
            QPointF(endPtx, endPty));
}

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void QPainterPath::quadTo	(	const QPointF &	c,
		const QPointF &	endPoint
	)

Adds a quadratic Bezier curve between the current position and the given endPoint with the control point specified by c.

After the curve is added, the current point is updated to be at the end point of the curve.

See also:

cubicTo(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 750 of file qpainterpath.cpp.

References c, cubicTo(), d, detach(), elementCount(), ensureData(), printf, qIsNan(), qWarning(), QPainterPath::Element::x, QPointF::x(), QPainterPath::Element::y, and QPointF::y().

Referenced by quadTo().

{
#ifdef QPP_DEBUG
    printf("QPainterPath::quadTo() (%.2f,%.2f), (%.2f,%.2f)\n",
           c.x(), c.y(), e.x(), e.y());
#endif
#ifndef QT_NO_DEBUG
    if (qIsNan(c.x()) || qIsNan(c.y()) || qIsNan(e.x()) || qIsNan(e.y()))
        qWarning("QPainterPath::quadTo: Adding point where x or y is NaN, results are undefined");
#endif
    ensureData();
    detach();

    Q_D(QPainterPath);
    Q_ASSERT(!d->elements.isEmpty());
    const QPainterPath::Element &elm = d->elements.at(elementCount()-1);
    QPointF prev(elm.x, elm.y);

    // Abort on empty curve as a stroker cannot handle this and the
    // curve is irrelevant anyway.
    if (prev == c && c == e)
        return;

    QPointF c1((prev.x() + 2*c.x()) / 3, (prev.y() + 2*c.y()) / 3);
    QPointF c2((e.x() + 2*c.x()) / 3, (e.y() + 2*c.y()) / 3);
    cubicTo(c1, c2, e);
}

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void QPainterPath::quadTo	(	qreal	cx,
		qreal	cy,
		qreal	endPointX,
		qreal	endPointY
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Adds a quadratic Bezier curve between the current point and the endpoint ({endPointX}, {endPointY}) with the control point specified by ({cx}, {cy}).

Definition at line 238 of file qpainterpath.h.

References quadTo().

{
    quadTo(QPointF(ctrlPtx, ctrlPty), QPointF(endPtx, endPty));
}

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QPointF QPainterPath::currentPosition

(

)

const

Returns the current position of the path.

Definition at line 903 of file qpainterpath.cpp.

References d_func(), d_ptr, and elements.

Referenced by SortingBox::SortingBox().

{
    return !d_ptr || d_func()->elements.isEmpty()
        ? QPointF()
        : QPointF(d_func()->elements.last().x, d_func()->elements.last().y);
}

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void QPainterPath::addRect

(

const QRectF &

rectangle

)

Adds the given rectangle to this path as a closed subpath.

The rectangle is added as a clockwise set of lines. The painter path's current position after the rectangle has been added is at the top-left corner of the rectangle.

100% qpainterpath-addrectangle.png

        QLinearGradient myGradient;
        QPen myPen;
        QRectF myRectangle;

        QPainterPath myPath;
        myPath.addRect(myRectangle);

        QPainter painter(this);
        painter.setBrush(myGradient);
        painter.setPen(myPen);
        painter.drawPath(myPath);

See also:

addRegion(), lineTo(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 951 of file qpainterpath.cpp.

References d_func(), detach(), elements, ensureData(), QRectF::height(), QRectF::isNull(), LineToElement, moveTo(), qIsNan(), qWarning(), QPainterPathData::require_moveTo, QRectF::width(), QRectF::x(), and QRectF::y().

Referenced by addRect(), addRegion(), addText(), Launcher::addTitleBackground(), QGraphicsItem::collidesWithPath(), QPainter::drawRects(), QPaintEngine::drawTextItem(), Window::setupShapes(), Launcher::showCategories(), SortingBox::SortingBox(), and QGraphicsPixmapItemPrivate::updateShape().

{
#ifndef QT_NO_DEBUG
    if (qIsNan(r.x()) || qIsNan(r.y()) || qIsNan(r.width()) || qIsNan(r.height()))
        qWarning("QPainterPath::addRect: Adding rect where a parameter is NaN, results are undefined");
#endif
    if (r.isNull())
        return;

    ensureData();
    detach();

    d_func()->elements.reserve(d_func()->elements.size() + 5);
    moveTo(r.x(), r.y());

    Element l1 = { r.x() + r.width(), r.y(), LineToElement };
    Element l2 = { r.x() + r.width(), r.y() + r.height(), LineToElement };
    Element l3 = { r.x(), r.y() + r.height(), LineToElement };
    Element l4 = { r.x(), r.y(), LineToElement };

    d_func()->elements << l1 << l2 << l3 << l4;
    d_func()->require_moveTo = true;
}

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void QPainterPath::addRect	(	qreal	x,
		qreal	y,
		qreal	width,
		qreal	height
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Adds a rectangle at position ({x}, {y}), with the given width and height, as a closed subpath.

Definition at line 248 of file qpainterpath.h.

References addRect().

{
    addRect(QRectF(x, y, w, h));
}

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void QPainterPath::addEllipse

(

const QRectF &

boundingRectangle

)

Creates an ellipse within the the specified boundingRectangle and adds it to the painter path as a closed subpath.

The ellipse is composed of a clockwise curve, starting and finishing at zero degrees (the 3 o'clock position).

100% qpainterpath-addellipse.png

        QLinearGradient myGradient;
        QPen myPen;
        QRectF boundingRectangle;

        QPainterPath myPath;
        myPath.addEllipse(boundingRectangle);

        QPainter painter(this);
        painter.setBrush(myGradient);
        painter.setPen(myPen);
        painter.drawPath(myPath);

See also:

arcTo(), QPainter::drawEllipse(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 1052 of file qpainterpath.cpp.

References boundingRect(), cubicTo(), d, d_func(), detach(), ensureData(), QRectF::height(), QRectF::isNull(), moveTo(), qIsNan(), qt_curves_for_arc(), qWarning(), QPainterPathData::require_moveTo, start, QRectF::width(), QRectF::x(), and QRectF::y().

Referenced by addEllipse(), Window::setupShapes(), and SortingBox::SortingBox().

{
#ifndef QT_NO_DEBUG
    if (qIsNan(boundingRect.x()) || qIsNan(boundingRect.y())
        || qIsNan(boundingRect.width()) || qIsNan(boundingRect.height()))
        qWarning("QPainterPath::addEllipse: Adding ellipse where a parameter is NaN, results are undefined");
#endif
    if (boundingRect.isNull())
        return;

    ensureData();
    detach();

    Q_D(QPainterPath);
    d->elements.reserve(d->elements.size() + 13);

    QPointF pts[12];
    int point_count;
    QPointF start = qt_curves_for_arc(boundingRect, 0, 360, pts, &point_count);

    moveTo(start);
    cubicTo(pts[0], pts[1], pts[2]);           // 0 -> 270
    cubicTo(pts[3], pts[4], pts[5]);           // 270 -> 180
    cubicTo(pts[6], pts[7], pts[8]);           // 180 -> 90
    cubicTo(pts[9], pts[10], pts[11]);         // 90 - >0
    d_func()->require_moveTo = true;
}

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void QPainterPath::addEllipse	(	qreal	x,
		qreal	y,
		qreal	width,
		qreal	height
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Creates an ellipse within the bounding rectangle defined by its top-left corner at (x, y), width and height, and adds it to the painter path as a closed subpath.

Definition at line 243 of file qpainterpath.h.

References addEllipse().

{
    addEllipse(QRectF(x, y, w, h));
}

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void QPainterPath::addPolygon

(

const QPolygonF &

polygon

)

Adds the given polygon to the path as an (unclosed) subpath.

Note that the current position after the polygon has been added, is the last point in polygon. To draw a line back to the first point, use the closeSubpath() function.

100% qpainterpath-addpolygon.png

        QLinearGradient myGradient;
        QPen myPen;
        QPolygonF myPolygon;

        QPainterPath myPath;
        myPath.addPolygon(myPolygon);

        QPainter painter(this);
        painter.setBrush(myGradient);
        painter.setPen(myPen);
        painter.drawPath(myPath);

See also:

lineTo(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 1004 of file qpainterpath.cpp.

References QVector< T >::at(), d_func(), detach(), elements, ensureData(), QVector< T >::first(), i, QVector< T >::isEmpty(), LineToElement, moveTo(), QVector< T >::size(), QPointF::x(), and QPointF::y().

Referenced by QGraphicsScene::items(), and QGraphicsView::mouseMoveEvent().

{
    if (polygon.isEmpty())
        return;

    ensureData();
    detach();

    d_func()->elements.reserve(d_func()->elements.size() + polygon.size());

    moveTo(polygon.first());
    for (int i=1; i<polygon.size(); ++i) {
        Element elm = { polygon.at(i).x(), polygon.at(i).y(), LineToElement };
        d_func()->elements << elm;
    }
}

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void QPainterPath::addText	(	const QPointF &	point,
		const QFont &	font,
		const QString &	text
	)

Adds the given text to this path as a set of closed subpaths created from the font supplied. The subpaths are positioned so that the left end of the text's baseline lies at the specified point.

100% qpainterpath-addtext.png

        QLinearGradient myGradient;
        QPen myPen;
        QFont myFont;
        QPointF baseline(x, y);

        QPainterPath myPath;
        myPath.addText(baseline, myFont, tr("Qt"));

        QPainter painter(this);
        painter.setBrush(myGradient);
        painter.setPen(myPen);
        painter.drawPath(myPath);

See also:

QPainter::drawText(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 1111 of file qpainterpath.cpp.

References QFontEngine::addOutlineToPath(), addRect(), QScriptItem::analysis, QFontEngine::ascent(), QTextEngine::bidiReorder(), QFont::d, detach(), QFontPrivate::engineForScript(), ensureData(), QTextEngine::glyphs(), i, QString::isEmpty(), QScriptItem::isObject, QScriptItem::isTab, layout, QTextEngine::layoutData, QScriptLine::length, levels, QTextEngine::lines, QFontEngine::lineThickness(), QScriptItem::num_glyphs, QFontPrivate::overline, QTextItem::RightToLeft, QFontPrivate::strikeOut, QFixed::toReal(), QFontPrivate::underline, QFontEngine::underlinePosition(), QScriptItem::width, QPointF::x(), x, QPointF::y(), and y.

Referenced by addText(), and Window::setupShapes().

{
    if (text.isEmpty())
        return;

    ensureData();
    detach();

    QTextLayout layout(text, f);
    layout.setCacheEnabled(true);
    QTextEngine *eng = layout.engine();
    layout.beginLayout();
    QTextLine line = layout.createLine();
    layout.endLayout();
    const QScriptLine &sl = eng->lines[0];
    if (!sl.length || !eng->layoutData)
        return;

    int nItems = eng->layoutData->items.size();

    qreal x(point.x());
    qreal y(point.y());

    QVarLengthArray<int> visualOrder(nItems);
    QVarLengthArray<uchar> levels(nItems);
    for (int i = 0; i < nItems; ++i)
        levels[i] = eng->layoutData->items[i].analysis.bidiLevel;
    QTextEngine::bidiReorder(nItems, levels.data(), visualOrder.data());

    for (int i = 0; i < nItems; ++i) {
        int item = visualOrder[i];
        QScriptItem &si = eng->layoutData->items[item];

        if (!si.isTab && !si.isObject) {
            QGlyphLayout *glyphs = eng->glyphs(&si);
            QFontEngine *fe = f.d->engineForScript(si.analysis.script);
            Q_ASSERT(fe);
            fe->addOutlineToPath(x, y, glyphs, si.num_glyphs, this,
                                 si.analysis.bidiLevel % 2
                                 ? QTextItem::RenderFlags(QTextItem::RightToLeft)
                                 : QTextItem::RenderFlags(0));

            const qreal lw = fe->lineThickness().toReal();
            if (f.d->underline) {
                qreal pos = fe->underlinePosition().toReal();
                addRect(x, y + pos, si.width.toReal(), lw);
            }
            if (f.d->overline) {
                qreal pos = fe->ascent().toReal() + 1;
                addRect(x, y - pos, si.width.toReal(), lw);
            }
            if (f.d->strikeOut) {
                qreal pos = fe->ascent().toReal() / 3;
                addRect(x, y - pos, si.width.toReal(), lw);
            }
        }
        x += si.width.toReal();
    }
}

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void QPainterPath::addText	(	qreal	x,
		qreal	y,
		const QFont &	font,
		const QString &	text
	)			[inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Adds the given text to this path as a set of closed subpaths created from the font supplied. The subpaths are positioned so that the left end of the text's baseline lies at the point specified by (x, y).

Definition at line 253 of file qpainterpath.h.

References addText().

{
    addText(QPointF(x, y), f, text);
}

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void QPainterPath::addPath

(

const QPainterPath &

path

)

Adds the given path to this path as a closed subpath.

See also:

connectPath(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 1179 of file qpainterpath.cpp.

References QPainterPathData::cStart, d, d_func(), detach(), ensureData(), QPainterPathData::isClosed(), isEmpty(), and MoveToElement.

{
    if (other.isEmpty())
        return;

    ensureData();
    detach();

    QPainterPathData *d = reinterpret_cast<QPainterPathData *>(d_func());
    // Remove last moveto so we don't get multiple moveto's
    if (d->elements.last().type == MoveToElement)
        d->elements.remove(d->elements.size()-1);

    // Locate where our own current subpath will start after the other path is added.
    int cStart = d->elements.size() + other.d_func()->cStart;
    d->elements += other.d_func()->elements;
    d->cStart = cStart;

    d->require_moveTo = other.d_func()->isClosed();
}

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void QPainterPath::addRegion

(

const QRegion &

region

)

Adds the given region to the path by adding each rectangle in the region as a separate closed subpath.

See also:

addRect(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 1240 of file qpainterpath.cpp.

References addRect(), QVector< T >::at(), d_func(), detach(), ensureData(), i, QRegion::rects(), and QVector< T >::size().

Referenced by Q3SVGPaintEngine::updateClipRegion(), and QGraphicsPixmapItemPrivate::updateShape().

{
    ensureData();
    detach();

    QVector<QRect> rects = region.rects();
    d_func()->elements.reserve(rects.size() * 5);
    for (int i=0; i<rects.size(); ++i)
        addRect(rects.at(i));
}

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void QPainterPath::connectPath

(

const QPainterPath &

path

)

Connects the given path to this path by adding a line from the last element of this path to the first element of the given path.

See also:

addPath(), {QPainterPath::Composing a QPainterPath}{Composing a QPainterPath}

Definition at line 1210 of file qpainterpath.cpp.

References QPainterPathData::cStart, d, d_func(), detach(), ensureData(), isEmpty(), LineToElement, and MoveToElement.

{
    if (other.isEmpty())
        return;

    ensureData();
    detach();

    QPainterPathData *d = reinterpret_cast<QPainterPathData *>(d_func());
    // Remove last moveto so we don't get multiple moveto's
    if (d->elements.last().type == MoveToElement)
        d->elements.remove(d->elements.size()-1);

    // Locate where our own current subpath will start after the other path is added.
    int cStart = d->elements.size() + other.d_func()->cStart;
    int first = d->elements.size();
    d->elements += other.d_func()->elements;

    d->elements[first].type = LineToElement;
    if (cStart != first)
        d->cStart = cStart;
}

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bool QPainterPath::contains

(

const QPointF &

point

)

const

Returns true if the given point is inside the path, otherwise returns false.

See also:

intersects()

Definition at line 1799 of file qpainterpath.cpp.

References CurveToElement, d, d_func(), QBezier::fromPoints(), i, isEmpty(), LineToElement, MoveToElement, qt_painterpath_isect_curve(), qt_painterpath_isect_line(), and Qt::WindingFill.

Referenced by QGraphicsItem::collidesWithPath(), contains(), QGraphicsItem::contains(), intersects(), and VersionLabel::mouseReleaseEvent().

{
    if (isEmpty())
        return false;

    QPainterPathData *d = d_func();

    int winding_number = 0;

    QPointF last_pt;
    QPointF last_start;
    for (int i=0; i<d->elements.size(); ++i) {
        const Element &e = d->elements.at(i);

        switch (e.type) {

        case MoveToElement:
            if (i > 0) // implicitly close all paths.
                qt_painterpath_isect_line(last_pt, last_start, pt, &winding_number);
            last_start = last_pt = e;
            break;

        case LineToElement:
            qt_painterpath_isect_line(last_pt, e, pt, &winding_number);
            last_pt = e;
            break;

        case CurveToElement:
            {
                const QPainterPath::Element &cp2 = d->elements.at(++i);
                const QPainterPath::Element &ep = d->elements.at(++i);
                qt_painterpath_isect_curve(QBezier::fromPoints(last_pt, e, cp2, ep),
                                           pt, &winding_number);
                last_pt = ep;

            }
            break;

        default:
            break;
        }
    }

    // implicitly close last subpath
    if (last_pt != last_start)
        qt_painterpath_isect_line(last_pt, last_start, pt, &winding_number);

    return (d->fillRule == Qt::WindingFill
            ? (winding_number != 0)
            : ((winding_number % 2) != 0));
}

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bool QPainterPath::contains

(

const QRectF &

rectangle

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Returns true if the given rectangle is inside the path, otherwise returns false.

Definition at line 2078 of file qpainterpath.cpp.

References QRectF::bottomLeft(), QRectF::bottomRight(), QRectF::center(), QRectF::contains(), contains(), controlPointRect(), CurveToElement, d, fillRule(), i, isEmpty(), LineToElement, MoveToElement, Qt::OddEvenFill, qt_painterpath_check_crossing(), QRectF::topLeft(), and QRectF::topRight().

{
    Q_D(QPainterPath);

    // the path is empty or the control point rect doesn't completely
    // cover the rectangle we abort stratight away.
    if (isEmpty() || !controlPointRect().contains(rect))
        return false;

    // if there are intersections, chances are that the rect is not
    // contained, except if we have winding rule, in which case it
    // still might.
    if (qt_painterpath_check_crossing(this, rect)) {
        if (fillRule() == Qt::OddEvenFill) {
            return false;
        } else {
            // Do some wague sampling in the winding case. This is not
            // precise but it should mostly be good enough.
            if (!contains(rect.topLeft()) ||
                !contains(rect.topRight()) ||
                !contains(rect.bottomRight()) ||
                !contains(rect.bottomLeft()))
                return false;
        }
    }

    // If there exists a point inside that is not part of the path its
    // because: rectangle lies completely outside path or a subpath
    // excludes parts of the rectangle. Both cases mean that the rect
    // is not contained
    if (!contains(rect.center()))
        return false;

    // If there are any subpaths inside this rectangle we need to
    // check if they are still contained as a result of the fill
    // rule. This can only be the case for WindingFill though. For
    // OddEvenFill the rect will never be contained if it surrounds a
    // subpath. (the case where two subpaths are completely identical
    // can be argued but we choose to neglect it).
    for (int i=0; i<d->elements.size(); ++i) {
        const Element &e = d->elements.at(i);
        if (e.type == QPainterPath::MoveToElement && rect.contains(e)) {
            if (fillRule() == Qt::OddEvenFill)
                return false;

            bool stop = false;
            for (; !stop && i<d->elements.size(); ++i) {
                const Element &el = d->elements.at(i);
                switch (el.type) {
                case MoveToElement:
                    stop = true;
                    break;
                case LineToElement:
                    if (!contains(el))
                        return false;
                    break;
                case CurveToElement:
                    if (!contains(d->elements.at(i+2)))
                        return false;
                    i += 2;
                    break;
                default:
                    break;
                }
            }

            // compensate for the last ++i in the inner for
            --i;
        }
    }

    return true;
}

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bool QPainterPath::intersects

(

const QRectF &

rectangle

)

const

Returns true if any point in the given rectangle intersects the path; otherwise returns false.

There is an intersection if any of the lines making up the rectangle crosses a part of the path or if any part of the rectangle overlaps with any area enclosed by the path. This function respects the current fillRule to determine what is considered inside the path.

See also:

contains()

Definition at line 2045 of file qpainterpath.cpp.

References QRectF::center(), QRectF::contains(), contains(), controlPointRect(), d, i, isEmpty(), MoveToElement, and qt_painterpath_check_crossing().

{
    if (isEmpty() || !controlPointRect().intersects(rect))
        return false;

    // If any path element cross the rect its bound to be an intersection
    if (qt_painterpath_check_crossing(this, rect))
        return true;

    if (contains(rect.center()))
        return true;

    Q_D(QPainterPath);

    // Check if the rectangle surounds any subpath...
    for (int i=0; i<d->elements.size(); ++i) {
        const Element &e = d->elements.at(i);
        if (e.type == QPainterPath::MoveToElement && rect.contains(e))
            return true;
    }

    return false;
}

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QRectF QPainterPath::boundingRect

(

)

const

Returns the bounding rectangle of this painter path as a rectangle with floating point precision.

See also:

controlPointRect()

Definition at line 1384 of file qpainterpath.cpp.

References b, CurveToElement, d, QBezier::fromPoints(), i, isEmpty(), LineToElement, MoveToElement, qt_painterpath_bezier_extrema(), QTextStream::right(), and right().

Referenced by addEllipse(), Launcher::addTitleBackground(), PaintArea::mousePressEvent(), PathDeformRenderer::paint(), QSvgPath::QSvgPath(), and PanelShape::rect().

{
    Q_D(QPainterPath);
    if (isEmpty())
        return QRect();

    qreal minx, maxx, miny, maxy;
    minx = maxx = d->elements.at(0).x;
    miny = maxy = d->elements.at(0).y;
    for (int i=1; i<d->elements.size(); ++i) {
        const Element &e = d->elements.at(i);

        switch (e.type) {
        case MoveToElement:
        case LineToElement:
            if (e.x > maxx) maxx = e.x;
            else if (e.x < minx) minx = e.x;
            if (e.y > maxy) maxy = e.y;
            else if (e.y < miny) miny = e.y;
            break;
        case CurveToElement:
            {
                QBezier b = QBezier::fromPoints(d->elements.at(i-1),
                                                e,
                                                d->elements.at(i+1),
                                                d->elements.at(i+2));
                QRectF r = qt_painterpath_bezier_extrema(b);
                qreal right = r.right();
                qreal bottom = r.bottom();
                if (r.x() < minx) minx = r.x();
                if (right > maxx) maxx = right;
                if (r.y() < miny) miny = r.y();
                if (bottom > maxy) maxy = bottom;
                i += 2;
            }
            break;
        default:
            break;
        }
    }
    return QRectF(minx, miny, maxx - minx, maxy - miny);
}

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QRectF QPainterPath::controlPointRect

(

)

const

Returns the rectangle containing all the points and control points in this path.

This function is significantly faster to compute than the exact boundingRect(), and the returned rectangle is always a superset of the rectangle returned by boundingRect().

See also:

boundingRect()

Definition at line 1437 of file qpainterpath.cpp.

References d, i, and isEmpty().

Referenced by contains(), intersects(), and QGraphicsPathItem::setPath().

{
    Q_D(QPainterPath);
    if (isEmpty())
        return QRect();

    qreal minx, maxx, miny, maxy;
    minx = maxx = d->elements.at(0).x;
    miny = maxy = d->elements.at(0).y;
    for (int i=1; i<d->elements.size(); ++i) {
        const Element &e = d->elements.at(i);
        if (e.x > maxx) maxx = e.x;
        else if (e.x < minx) minx = e.x;
        if (e.y > maxy) maxy = e.y;
        else if (e.y < miny) miny = e.y;
    }
    return QRectF(minx, miny, maxx - minx, maxy - miny);
}

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Qt::FillRule QPainterPath::fillRule

(

)

const

Returns the painter path's currently set fill rule.

See also:

setFillRule()

Definition at line 1257 of file qpainterpath.cpp.

References d_func(), QPainterPathData::fillRule, isEmpty(), and Qt::OddEvenFill.

Referenced by contains(), QRasterPaintEngine::updateState(), and QX11PaintEngine::updateState().

{
    return isEmpty() ? Qt::OddEvenFill : d_func()->fillRule;
}

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void QPainterPath::setFillRule

(

Qt::FillRule

fillRule

)

Sets the fill rule of the painter path to the given fillRule. Qt provides two methods for filling paths:

qt-fillrule-oddeven.png qt-fillrule-winding.png Qt::OddEvenFill (default) Qt::WindingFill

See also:

fillRule()

Definition at line 1279 of file qpainterpath.cpp.

References d_func(), detach(), ensureData(), and QPainterPathData::fillRule.

Referenced by createPathNode(), QPainter::drawConvexPolygon(), QX11PaintEngine::drawPath(), QPainter::drawPolygon(), QPaintEngine::drawTextItem(), RenderArea::setFillRule(), and Window::setupShapes().

{
    ensureData();
    detach();

    d_func()->fillRule = fillRule;
}

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bool QPainterPath::isEmpty

(

)

const [inline]

Returns true if there are no elements in this path, otherwise returns false.

See also:

elementCount()

Definition at line 258 of file qpainterpath.h.

References d_ptr, QPainterPathPrivate::elements, QVector< T >::first(), MoveToElement, QVector< T >::size(), and QPainterPath::Element::type.

Referenced by addPath(), boundingRect(), closeSubpath(), QGraphicsItem::collidesWithPath(), connectPath(), contains(), controlPointRect(), QPainterPrivate::draw_helper(), QX11PaintEngine::drawPath(), fillRule(), intersects(), PaintArea::mousePressEvent(), QGraphicsPathItem::QGraphicsPathItem(), toReversed(), and toSubpathPolygons().

{
    return !d_ptr || (d_ptr->elements.size() == 1 && d_ptr->elements.first().type == MoveToElement);
}

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QPainterPath QPainterPath::toReversed

(

)

const

Creates and returns a reversed copy of the path.

It is the order of the elements that is reversed: If a QPainterPath is composed by calling the moveTo(), lineTo() and cubicTo() functions in the specified order, the reversed copy is composed by calling cubicTo(), lineTo() and moveTo().

Definition at line 1474 of file qpainterpath.cpp.

References cubicTo(), CurveToDataElement, CurveToElement, d, i, isEmpty(), lineTo(), LineToElement, moveTo(), MoveToElement, QPainterPath::Element::type, QPainterPath::Element::x, x, QPainterPath::Element::y, and y.

{
    Q_D(const QPainterPath);
    QPainterPath rev;

    if (isEmpty()) {
        rev = *this;
        return rev;
    }

    rev.moveTo(d->elements.at(d->elements.size()-1).x, d->elements.at(d->elements.size()-1).y);

    for (int i=d->elements.size()-1; i>=1; --i) {
        const QPainterPath::Element &elm = d->elements.at(i);
        const QPainterPath::Element &prev = d->elements.at(i-1);
        switch (elm.type) {
        case LineToElement:
            rev.lineTo(prev.x, prev.y);
            break;
        case MoveToElement:
            rev.moveTo(prev.x, prev.y);
            break;
        case CurveToDataElement:
            {
                Q_ASSERT(i>=3);
                const QPainterPath::Element &cp1 = d->elements.at(i-2);
                const QPainterPath::Element &sp = d->elements.at(i-3);
                Q_ASSERT(prev.type == CurveToDataElement);
                Q_ASSERT(cp1.type == CurveToElement);
                rev.cubicTo(prev.x, prev.y, cp1.x, cp1.y, sp.x, sp.y);
                i -= 2;
                break;
            }
        default:
            Q_ASSERT(!"qt_reversed_path");
            break;
        }
    }
    //qt_debug_path(rev);
    return rev;
}

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QList< QPolygonF > QPainterPath::toSubpathPolygons

(

const QMatrix &

matrix = QMatrix()

)

const

Converts the path into a list of polygons using the given transformation matrix, and returns the list.

This function creates one polygon for each subpath regardless of intersecting subpaths (i.e. overlapping bounding rectangles). To make sure that such overlapping subpaths are filled correctly, use the toFillPolygons() function instead.

See also:

toFillPolygons(), toFillPolygon(), {QPainterPath::QPainterPath Conversion}{QPainterPath Conversion}

Definition at line 1529 of file qpainterpath.cpp.

References QVector< T >::clear(), CurveToDataElement, CurveToElement, d, elementCount(), QBezier::fromPoints(), i, isEmpty(), LineToElement, MoveToElement, QVector< T >::reserve(), and QVector< T >::size().

Referenced by toFillPolygon(), and toFillPolygons().

{
    Q_D(const QPainterPath);
    QList<QPolygonF> flatCurves;
    if (isEmpty())
        return flatCurves;

    QPolygonF current;
    for (int i=0; i<elementCount(); ++i) {
        const QPainterPath::Element &e = d->elements.at(i);
        switch (e.type) {
        case QPainterPath::MoveToElement:
            if (current.size() > 1)
                flatCurves += current;
            current.clear();
            current.reserve(16);
            current += QPointF(e.x, e.y) * matrix;
            break;
        case QPainterPath::LineToElement:
            current += QPointF(e.x, e.y) * matrix;
            break;
        case QPainterPath::CurveToElement: {
            Q_ASSERT(d->elements.at(i+1).type == QPainterPath::CurveToDataElement);
            Q_ASSERT(d->elements.at(i+2).type == QPainterPath::CurveToDataElement);
            QBezier bezier = QBezier::fromPoints(QPointF(d->elements.at(i-1).x, d->elements.at(i-1).y) * matrix,
                                       QPointF(e.x, e.y) * matrix,
                                       QPointF(d->elements.at(i+1).x, d->elements.at(i+1).y) * matrix,
                                                 QPointF(d->elements.at(i+2).x, d->elements.at(i+2).y) * matrix);
            bezier.addToPolygon(&current);
            i+=2;
            break;
        }
        case QPainterPath::CurveToDataElement:
            Q_ASSERT(!"QPainterPath::toSubpathPolygons(), bad element type");
            break;
        }
    }

    if (current.size()>1)
        flatCurves += current;

    return flatCurves;
}

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QList< QPolygonF > QPainterPath::toFillPolygons

(

const QMatrix &

matrix = QMatrix()

)

const

Converts the path into a list of polygons using the given transformation matrix, and returns the list.

The function differs from the toFillPolygon() function in that it creates several polygons. It is provided because it is usually faster to draw several small polygons than to draw one large polygon, even though the total number of points drawn is the same.

The toFillPolygons() function differs from the toSubpathPolygons() function in that it create only polygon for subpaths that have overlapping bounding rectangles.

Like the toFillPolygon() function, this function uses a rewinding technique to make sure that overlapping subpaths can be filled using the correct fill rule. Note that rewinding inserts addition lines in the polygons so the outline of the fill polygon does not match the outline of the path.

See also:

toSubpathPolygons(), toFillPolygon(), {QPainterPath::QPainterPath Conversion}{QPainterPath Conversion}

Definition at line 1636 of file qpainterpath.cpp.

References QVector< T >::at(), QList< T >::at(), QPolygonF::boundingRect(), QVector< T >::clear(), QVector< T >::first(), i, j, printf, qDebug(), rect_intersects(), QVector< T >::resize(), QVector< T >::size(), QList< T >::size(), and toSubpathPolygons().

{
    QList<QPolygonF> polys;

    QList<QPolygonF> subpaths = toSubpathPolygons(matrix);
    int count = subpaths.size();

    if (count == 0)
        return polys;

    QList<QRectF> bounds;
    for (int i=0; i<count; ++i)
        bounds += subpaths.at(i).boundingRect();

#ifdef QPP_FILLPOLYGONS_DEBUG
    printf("QPainterPath::toFillPolygons, subpathCount=%d\n", count);
    for (int i=0; i<bounds.size(); ++i)
        qDebug() << " bounds" << i << bounds.at(i);
#endif

    QVector< QList<int> > isects;
    isects.resize(count);

    // find all intersections
    for (int j=0; j<count; ++j) {
        if (subpaths.at(j).size() <= 2)
            continue;
        QRectF cbounds = bounds.at(j);
        for (int i=0; i<count; ++i) {
            if (rect_intersects(cbounds, bounds.at(i))) {
                isects[j] << i;
            }
        }
    }

#ifdef QPP_FILLPOLYGONS_DEBUG
    printf("Intersections before flattening:\n");
    for (int i = 0; i < count; ++i) {
        printf("%d: ", i);
        for (int j = 0; j < isects[i].size(); ++j) {
            printf("%d ", isects[i][j]);
        }
        printf("\n");
    }
#endif

    // flatten the sets of intersections
    for (int i=0; i<count; ++i) {
        const QList<int> &current_isects = isects.at(i);
        for (int j=0; j<current_isects.size(); ++j) {
            int isect_j = current_isects.at(j);
            if (isect_j == i)
                continue;
            for (int k=0; k<isects[isect_j].size(); ++k) {
                int isect_k = isects[isect_j][k];
                if (isect_k != i && !isects.at(i).contains(isect_k)) {
                    isects[i] += isect_k;
                }
            }
            isects[isect_j].clear();
        }
    }

#ifdef QPP_FILLPOLYGONS_DEBUG
    printf("Intersections after flattening:\n");
    for (int i = 0; i < count; ++i) {
        printf("%d: ", i);
        for (int j = 0; j < isects[i].size(); ++j) {
            printf("%d ", isects[i][j]);
        }
        printf("\n");
    }
#endif

    // Join the intersected subpaths as rewinded polygons
    for (int i=0; i<count; ++i) {
        const QList<int> &subpath_list = isects[i];
        if (!subpath_list.isEmpty()) {
            QPolygonF buildUp;
            for (int j=0; j<subpath_list.size(); ++j) {
                buildUp += subpaths.at(subpath_list.at(j));
                if (!buildUp.isClosed())
                    buildUp += buildUp.first();
            }
            polys += buildUp;
        }
    }

    return polys;
}

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QPolygonF QPainterPath::toFillPolygon

(

const QMatrix &

matrix = QMatrix()

)

const

Converts the path into a polygon using the given transformation matrix, and returns the polygon.

The polygon is created by first converting all subpaths to polygons, then using a rewinding technique to make sure that overlapping subpaths can be filled using the correct fill rule.

Note that rewinding inserts addition lines in the polygon so the outline of the fill polygon does not match the outline of the path.

See also:

toSubpathPolygons(), toFillPolygons(), {QPainterPath::QPainterPath Conversion}{QPainterPath Conversion}

Definition at line 1588 of file qpainterpath.cpp.

References QList< T >::at(), QList< T >::first(), QVector< T >::first(), i, QPolygonF::isClosed(), QList< T >::isEmpty(), QList< T >::size(), and toSubpathPolygons().

Referenced by QGraphicsItem::collidesWithPath(), PieView::itemRegion(), QRasterPaintEngine::updateState(), and QX11PaintEngine::updateState().

{

    QList<QPolygonF> flats = toSubpathPolygons(matrix);
    QPolygonF polygon;
    if (flats.isEmpty())
        return polygon;
    QPointF first = flats.first().first();
    for (int i=0; i<flats.size(); ++i) {
        polygon += flats.at(i);
        if (!flats.at(i).isClosed())
            polygon += flats.at(i).first();
        if (i > 0)
            polygon += first;
    }
    return polygon;
}

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int QPainterPath::elementCount

(

)

const [inline]

Returns the number of path elements in the painter path.

See also:

ElementType, elementAt(), isEmpty()

Definition at line 263 of file qpainterpath.h.

References d_ptr, QPainterPathPrivate::elements, and QVector< T >::size().

Referenced by elementAt(), quadTo(), setElementPositionAt(), and toSubpathPolygons().

{
    return d_ptr ? d_ptr->elements.size() : 0;
}

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const QPainterPath::Element & QPainterPath::elementAt

(

int

index

)

const [inline]

Returns the element at the given index in the painter path.

See also:

ElementType, elementCount(), isEmpty()

Definition at line 268 of file qpainterpath.h.

References QVector< T >::at(), d_ptr, elementCount(), and QPainterPathPrivate::elements.

Referenced by QGraphicsItem::collidesWithPath().

{
    Q_ASSERT(d_ptr);
    Q_ASSERT(i >= 0 && i < elementCount());
    return d_ptr->elements.at(i);
}

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void QPainterPath::setElementPositionAt	(	int	index,
		qreal	x,
		qreal	y
	)			[inline]

Since:

4.2

Sets the x and y coordinate of the element at index index to x and y.

Definition at line 275 of file qpainterpath.h.

References d_ptr, detach(), elementCount(), QPainterPathPrivate::elements, QPainterPath::Element::x, and QPainterPath::Element::y.

{
    Q_ASSERT(d_ptr);
    Q_ASSERT(i >= 0 && i < elementCount());
    detach();
    QPainterPath::Element &e = d_ptr->elements[i];
    e.x = x;
    e.y = y;
}

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bool QPainterPath::operator==

(

const QPainterPath &

path

)

const

Returns true if this painterpath is equal to the given path.

Note that comparing paths may involve a per element comparison which can be slow for complex paths.

See also:

operator!=()

Definition at line 2162 of file qpainterpath.cpp.

References d, d_func(), i, and path.

{
    QPainterPathData *d = reinterpret_cast<QPainterPathData *>(d_func());
    if (path.d_func() == d)
        return true;
    else if (!d || !path.d_func())
        return false;
    bool equal = d->fillRule == path.d_func()->fillRule && d->elements.size() == path.d_func()->elements.size();
    for (int i = 0; i < d->elements.size() && equal; ++i)
        equal = d->elements.at(i) == path.d_func()->elements.at(i);
    return equal;
}

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bool QPainterPath::operator!=

(

const QPainterPath &

path

)

const

Returns true if this painter path differs from the given path.

Note that comparing paths may involve a per element comparison which can be slow for complex paths.

See also:

operator==()

Definition at line 2184 of file qpainterpath.cpp.

References path.

{
    return !(*this==path);
}

void QPainterPath::ensureData

(

)

[inline, private]

Definition at line 138 of file qpainterpath.h.

References d_ptr.

Referenced by addEllipse(), addPath(), addPolygon(), addRect(), addRegion(), addText(), arcTo(), connectPath(), cubicTo(), lineTo(), moveTo(), quadTo(), and setFillRule().

{ if (!d_ptr) ensureData_helper(); }

void QPainterPath::ensureData_helper

(

)

[private]

Definition at line 507 of file qpainterpath.cpp.

References d_ptr, data, MoveToElement, and qAtomicSetPtr().

{
    QPainterPathPrivate *data = new QPainterPathData;
    data->elements.reserve(16);
    QPainterPath::Element e = { 0, 0, QPainterPath::MoveToElement };
    data->elements << e;
    data = qAtomicSetPtr(&d_ptr, data);
    if (data && !data->ref.deref())
        delete (QPainterPathData *) data;
    Q_ASSERT(d_ptr != 0);
}

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void QPainterPath::detach

(

)

[inline, private]

Definition at line 286 of file qpainterpath.h.

References d_ptr, detach_helper(), and QPainterPathPrivate::ref.

Referenced by addEllipse(), addPath(), addPolygon(), addRect(), addRegion(), addText(), arcTo(), closeSubpath(), connectPath(), cubicTo(), lineTo(), moveTo(), quadTo(), setElementPositionAt(), and setFillRule().

{
    if (d_ptr->ref != 1)
        detach_helper();
}

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void QPainterPath::detach_helper

(

)

[private]

Definition at line 496 of file qpainterpath.cpp.

References d_func(), d_ptr, data, qAtomicSetPtr(), and QPainterPathData.

Referenced by detach().

{
    QPainterPathPrivate *data = new QPainterPathData(*d_func());
    data = qAtomicSetPtr(&d_ptr, data);
    if (data && !data->ref.deref())
        delete (QPainterPathData *) data;
}

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QPainterPathData* QPainterPath::d_func

(

)

const [inline, private]

Definition at line 143 of file qpainterpath.h.

References d_ptr.

Referenced by addEllipse(), addPath(), addPolygon(), addRect(), addRegion(), closeSubpath(), connectPath(), contains(), cubicTo(), currentPosition(), detach_helper(), fillRule(), lineTo(), moveTo(), operator=(), operator==(), QPainterPath(), setFillRule(), and ~QPainterPath().

{ return reinterpret_cast<QPainterPathData *>(d_ptr); }

---

Friends And Related Function Documentation

friend class QPainterPathData [friend]

Definition at line 145 of file qpainterpath.h.

Referenced by detach_helper().

friend class QPainterPathStroker [friend]

Definition at line 146 of file qpainterpath.h.

friend class QPainterPathStrokerPrivate [friend]

Definition at line 147 of file qpainterpath.h.

friend class QMatrix [friend]

Definition at line 148 of file qpainterpath.h.

QDataStream & operator<<	(	QDataStream &	stream,
		const QPainterPath &	path
	)			[friend]

Writes the given painter path to the given stream, and returns a reference to the stream.

See also:

{Format of the QDataStream Operators}

Definition at line 2199 of file qpainterpath.cpp.

{
    if (p.isEmpty()) {
        s << 0;
        return s;
    }

    s << p.elementCount();
    for (int i=0; i < p.d_func()->elements.size(); ++i) {
        const QPainterPath::Element &e = p.d_func()->elements.at(i);
        s << int(e.type);
        s << double(e.x) << double(e.y);
    }
    s << p.d_func()->cStart;
    s << int(p.d_func()->fillRule);
    return s;
}

QDataStream & operator>>	(	QDataStream &	stream,
		QPainterPath &	path
	)			[friend]

Reads a painter path from the given stream into the specified path, and returns a reference to the stream.

See also:

{Format of the QDataStream Operators}

Definition at line 2226 of file qpainterpath.cpp.

{
    int size;
    s >> size;

    if (size == 0)
        return s;

    p.ensureData(); // in case if p.d_func() == 0
    if (p.d_func()->elements.size() == 1) {
        Q_ASSERT(p.d_func()->elements.at(0).type == QPainterPath::MoveToElement);
        p.d_func()->elements.clear();
    }
    p.d_func()->elements.reserve(p.d_func()->elements.size() + size);
    for (int i=0; i<size; ++i) {
        int type;
        double x, y;
        s >> type;
        s >> x;
        s >> y;
        Q_ASSERT(type >= 0 && type <= 3);
#ifndef QT_NO_DEBUG
        if (qIsNan(x) || qIsNan(y))
            qWarning("QDataStream::operator>>: Adding a NaN element to path, results are undefined");
#endif
        QPainterPath::Element elm = { x, y, QPainterPath::ElementType(type) };
        p.d_func()->elements.append(elm);
    }
    s >> p.d_func()->cStart;
    int fillRule;
    s >> fillRule;
    Q_ASSERT(fillRule == Qt::OddEvenFill || Qt::WindingFill);
    p.d_func()->fillRule = Qt::FillRule(fillRule);
    return s;
}

---

Member Data Documentation

QPainterPathPrivate* QPainterPath::d_ptr [private]

Definition at line 136 of file qpainterpath.h.

Referenced by currentPosition(), detach(), detach_helper(), elementAt(), elementCount(), ensureData_helper(), isEmpty(), operator=(), and setElementPositionAt().

---

The documentation for this class was generated from the following files:

• src/gui/painting/qpainterpath.h
• src/gui/painting/qpainterpath.cpp

---