Qwt User's Guide: QwtPixelMatrix Class Reference

Qwt User's Guide 6.1.2

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QwtPixelMatrix Class Reference

A bit field corresponding to the pixels of a rectangle. More...

`#include <qwt_pixel_matrix.h>`

Inheritance diagram for QwtPixelMatrix:
[legend]

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

## 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.