Home | All Classes | Main Classes | Annotated | Grouped Classes | Functions

QPainterPath Class Reference

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

#include <QPainterPath>

Public Functions


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. A painter path can be used for filling, outlining, and clipping. The main advantage of painter paths over normal drawing operations is that complex shapes only need to be created once, but they can be drawn many times using only calls to QPainter::drawPath().

Building blocks can be joined in closed subpaths, such as a rectangle or an ellipse, or they can exist independently as unclosed subpaths. Note that unclosed paths will not be filled.

Below is a code snippet that shows how a path can be used. The painter in this case has a pen width of 3 and a light blue brush. The painter path is initially empty when constructed. We first add a rectangle, which becomes a closed subpath. We then add two bezier curves, and finally draw the entire path.

    QPainterPath path;
    path.addRect(20, 20, 80, 80);

    path.moveTo(0, 0);
    path.curveTo(99, 0,  50, 50,  99, 99);
    path.curveTo(0, 99,  50, 50,  0, 0);

    painter.drawPath(path);

See also QPainter.


Member Function Documentation

QPainterPath::QPainterPath ()

Constructs a new empty QPainterPath.

QPainterPath::QPainterPath ( const QPointF & startPoint )

Creates a new painter path with startPoint as starting poing

QPainterPath::QPainterPath ( const QPainterPath & other )

Creates a new painter path that is a copy of the other painter path.

QPainterPath::~QPainterPath ()

Destroys the painter path.

void QPainterPath::addEllipse ( const QRectF & boundingRect )

Creates an ellipse within the bounding rectangle specified by boundingRect and adds it to the painter path.

If the current subpath is closed, a new subpath is started. The ellipse is clockwise starting and starting zero degrees.

void QPainterPath::addEllipse ( float x, float y, float width, float height )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Creates an ellipse within a bounding rectangle defined by its top-left corner at (x, y), width and height, and adds it to the painter path.

If the current subpath is closed, a new subpath is started. The ellipse is clockwise starting and starting zero degrees.

void QPainterPath::addPath ( const QPainterPath & other )

Adds the path other to this path. If the current subpath is path is unclosed, other is joined with it.

void QPainterPath::addPolygon ( const QPolygon & polygon )

Adds the polygon to path as a new subpath. If the current subpath is closed, a new subpath is started at the polygons first point.

void QPainterPath::addRect ( const QRectF & rectangle )

Adds the rectangle to this path as a closed subpath. The rectangle is added as a clockwise set of lines. An empty subpath with current position at (0, 0) is in use after this function returns. The rectangle is oriented clockwise starting at topleft.

void QPainterPath::addRect ( float x, float y, float width, float height )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Adds a rectangle at position (x, y), with the given width and height. The rectangle is added as a clockwise set of lines. An empty subpath with current position at (0, 0) is in use after this function returns.

void QPainterPath::addRegion ( const QRegion & region )

Adds the region region to the path. This is done by converting the region into a set of lines which enclose it.

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 point specified.

See also QPainter::drawText.

void QPainterPath::addText ( float x, float y, const QFont & font, const QString & text )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

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).

See also QPainter::drawText.

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

Creates an arc that occupies the given rectangle, beginning at startAngle and extending sweepLength degrees anti-clockwise. Angles are specified in degrees. This function connects the current point to the starting point of the arc if they are not already connected.

See also QPainter::drawArc.

void QPainterPath::arcTo ( float x, float y, float width, float height, float startAngle, float sweepLength )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

The arc's lies within the rectangle given by the point (x, y), width and height, beginning at startAngle and extending sweepLength degrees anti-clockwise. Angles are specified in degrees. This function connects the current point to the starting point of the arc if they are not already connected.

See also QPainter::drawArc.

QRectF QPainterPath::boundingRect () const

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

void QPainterPath::closeSubpath ()

Closes the current subpath. If the subpath does not contain any elements, the function does nothing. A new subpath is automatically begun when the current subpath is closed. The current point of the new path is (0, 0).

bool QPainterPath::contains ( const QPointF & pt ) const

Returns true if the point pt is contained by the path; otherwise returns false.

bool QPainterPath::contains ( const QRectF & rect ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns true if the rect rect is inside the path; otherwise returns false.

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

Adds a Bezier curve between the current point and endPoint with control points specified by c1, and c2. After the curve is added, the current point is updated to be at the end point of the curve.

void QPainterPath::curveTo ( float ctrlPt1x, float ctrlPt1y, float ctrlPt2x, float ctrlPt2y, float endPtx, float endPty )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Adds a Bezier curve between the current point and the endpoint (endPtx, endPty) with control points specified by (ctrlPt1x, ctrlPt1y) and (ctrlPt2x, ctrlPt2y). After the curve is added, the current point is updated to be at the end point of the curve.

const QPainterPath::Element & QPainterPath::elementAt ( int index ) const

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

int QPainterPath::elementCount () const

Returns the number of path elements in the painter path.

Qt::FillRule QPainterPath::fillRule () const

Returns the fill rule of the painter path. The default fill rule is Qt::OddEvenFill.

See also Qt::FillRule and setFillRule().

bool QPainterPath::isEmpty () const

Returns true if there are no elements in this path.

void QPainterPath::lineTo ( const QPointF & endPoint )

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

void QPainterPath::lineTo ( float x, float y )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Draws a line from the current point to the point at (x, y). After the line is drawn, the current point is updated to be at the end point of the line.

void QPainterPath::moveTo ( const QPointF & point )

Moves the current point to the given point. Moving the current point will also start a new subpath. The previously current path will not be closed implicitly before the new one is started.

void QPainterPath::moveTo ( float x, float y )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Moves the current point to (x, y). Moving the current point will also start a new subpath. The previously current path will not be closed implicitly before the new one is started.

void QPainterPath::setFillRule ( Qt::FillRule fillRule )

QPolygon QPainterPath::toFillPolygon ( const QMatrix & matrix = QMatrix() ) const

Returns the painter path as a filled polygon.

QList<QPolygon> QPainterPath::toFillPolygons ( const QMatrix & matrix = QMatrix() ) const

Creates a polygon from the path.

QPainterPath QPainterPath::toReversed () const

Creates a reversed copy of this path and returns it

QList<QPolygon> QPainterPath::toSubpathPolygons ( const QMatrix & matrix = QMatrix() ) const

Returns a list of polygons corresponding to the subpaths in the painter path.

bool QPainterPath::operator!= ( const QPainterPath & path ) const

Returns true if this painterpath differs from path.

Comparing paths may involve a pr element comparrison which can be slow for complex paths.

QPainterPath & QPainterPath::operator+= ( const QPainterPath & other )

Appends the other painter path to this painter path and returns a reference to the result.

QPainterPath & QPainterPath::operator= ( const QPainterPath & other )

Assigns the other painter path to this painter path.

bool QPainterPath::operator== ( const QPainterPath & path ) const

Returns true if this painterpath is equal to path.

Comparing paths may involve a pr element comparrison which can be slow for complex paths.


Copyright © 2004 Trolltech Trademarks
Qt 4.0.0-b1