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# Q3PointArray Class Reference

    #include <Q3PointArray>

This class is part of the Qt 3 support library. It is provided to keep old source code working. We strongly advise against using it in new code. See the Porting Guide for more information.

Part of the Qt3Support module.

Inherits QPolygon.

- List of all members, including inherited members

### Public Functions

- Q3PointArray ()
- Q3PointArray ( const QRect & r, bool closed = false )
- Q3PointArray ( const QPolygon & other )
- Q3PointArray copy () const
- Q3PointArray cubicBezier () const
- bool isNull ()
- void makeArc ( int x, int y, int w, int h, int a1, int a2 )
- void makeArc ( int x, int y, int w, int h, int a1, int a2, const QMatrix & xf )
- void makeEllipse ( int x, int y, int w, int h )

- 12 public functions inherited from QPolygon
- 62 public functions inherited from QVector

### Additional Inherited Members

- 2 static public members inherited from QVector

## Detailed Description

The Q3PointArray class provides an array of points.

Q3PointArray is a QPolygon subclass that provides functions to make it more source compatible with the `QPointArray` class in Qt 3.

In Qt 4, we recommend that you use QPainterPath for representing arcs, ellipses, and Bezier curves, rather than QPolygon.

## Member Function Documentation

### Q3PointArray::Q3PointArray ()

Constructs an empty Q3PointArray.

### Q3PointArray::Q3PointArray ( const QRect & r, bool closed = false )

Constructs a point array from the rectangle r.

If closed is false, then the point array just contains the following four points of the rectangle ordered clockwise. The bottom-right point is located at (r.x() + r.width(), r.y() + r.height()).

### Q3PointArray::Q3PointArray ( const QPolygon & other )

Constructs a copy of other.

### Q3PointArray Q3PointArray::copy () const

Returns a copy of this Q3PointArray.

### Q3PointArray Q3PointArray::cubicBezier () const

Returns the Bezier points for the four control points in this array.

### bool Q3PointArray::isNull ()

Same as isEmpty().

### void Q3PointArray::makeArc ( int x, int y, int w, int h, int a1, int a2 )

Sets the points of the array to those describing an arc of an ellipse with size, width w by height h, and position (x, y), starting from angle a1 and spanning by angle a2. The resulting array has sufficient resolution for pixel accuracy (see the overloaded function which takes an additional QMatrix parameter).

Angles are specified in 16ths of a degree, i.e. a full circle equals 5760 (16*360). Positive values mean counter-clockwise, whereas negative values mean the clockwise direction. Zero degrees is at the 3 o'clock position.

### void Q3PointArray::makeArc ( int x, int y, int w, int h, int a1, int a2, const QMatrix & xf )

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

Sets the points of the array to those describing an arc of an ellipse with width w and height h and position (x, y), starting from angle a1, and spanning angle by a2, and transformed by the matrix xf. The resulting array has sufficient resolution for pixel accuracy.

Angles are specified in 16ths of a degree, i.e. a full circle equals 5760 (16 * 360). Positive values mean counter-clockwise, whereas negative values mean the clockwise direction. Zero degrees is at the 3 o'clock position.

### void Q3PointArray::makeEllipse ( int x, int y, int w, int h )

Sets the points of the array to those describing an ellipse with size, width w by height h, and position (x, y).

The returned array has sufficient resolution for use as pixels.