---
name: "QwtPixelMatrix"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtPixelMatrix"
---

# QwtPixelMatrix(3)

A bit field corresponding to the pixels of a rectangle.

## NAME

QwtPixelMatrix - A bit field corresponding to the pixels of a rectangle.

## SYNOPSIS

`#include <qwt_pixel_matrix.h>`

Inherits QBitArray.

### Public Member Functions

**QwtPixelMatrix** (const QRect &**rect**)\
 Constructor.  **~QwtPixelMatrix** ()\
 Destructor.  void **setRect** (const QRect &**rect**)\
 QRect **rect** () const\
 bool **testPixel** (int x, int y) const\
 Test if a pixel has been set.  bool **testAndSetPixel** (int x, int y, bool on)\
 Set a pixel and test if a pixel has been set before.  int **index** (int x, int y) const\
 Calculate the index in the bit field corresponding to a position.

## Detailed Description

A bit field corresponding to the pixels of a rectangle.

**QwtPixelMatrix** is intended to filter out duplicates in an unsorted array of points.

## Constructor & Destructor Documentation

### QwtPixelMatrix::QwtPixelMatrix (const QRect & rect)

Constructor.

**Parameters:**

*rect* Bounding rectangle for the matrix

## Member Function Documentation

### int QwtPixelMatrix::index (int x, int y) const` [inline]`

Calculate the index in the bit field corresponding to a position.

**Parameters:**

*x* X-coordinate \
 *y* Y-coordinate

**Returns:**

Index, when **rect()** contains pos - otherwise -1.

### QRect QwtPixelMatrix::rect () const

**Returns:**

Bounding rectangle

### void QwtPixelMatrix::setRect (const QRect & rect)

Set the bounding rectangle of the matrix

**Parameters:**

*rect* Bounding rectangle

**Note:**

All bits are cleared

### bool QwtPixelMatrix::testAndSetPixel (int x, int y, bool on)` [inline]`

Set a pixel and test if a pixel has been set before.

**Parameters:**

*x* X-coordinate \
 *y* Y-coordinate \
 *on* Set/Clear the pixel

**Returns:**

true, when pos is outside of **rect()**, or when the pixel was set before.

### bool QwtPixelMatrix::testPixel (int x, int y) const` [inline]`

Test if a pixel has been set.

**Parameters:**

*x* X-coordinate \
 *y* Y-coordinate

**Returns:**

true, when pos is outside of **rect()**, or when the pixel has already been set.

## Author

Generated automatically by Doxygen for Qwt User's Guide from the source code.