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QwtPixelMatrix(3) Qwt User's Guide QwtPixelMatrix(3)

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

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Wed Jan 2 2019 Version 6.1.4