QArrow Class Reference

Detailed Description

An arrow as a QGraphicsObject.

Definition at line 14 of file QArrow.h.

#include <QArrow.h>

Inheritance diagram for QArrow:

Collaboration diagram for QArrow:

Public Member Functions
	QArrow (qreal l, qreal a, qreal hl, qreal hw, QPen &pen, QGraphicsItem *parent=nullptr)
	QArrow (qreal l, qreal a, QPen &pen, QGraphicsItem *parent=nullptr)
	~QArrow () override
double	getLength ()
	Returns the length of the arrow.
double	getAngle ()
	Returns the orientation of the arrow.
void	paint (QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override
QRectF	boundingRect () const override
	The bounding box of the arrow.
void	setAngle (qreal a)
	Changes orientation of the arrow.
void	setLength (qreal l)
	Changes the length of the arrow.

Private Member Functions
double	calcCos (double angle)
double	calcSin (double angle)

Private Attributes
qreal	_arrowLength
qreal	_arrowAngle
qreal	_headLength
qreal	_headWidth
QPen	_arrowPen

Constructor & Destructor Documentation

QArrow() [1/2]

QArrow::QArrow	(	qreal	l,
		qreal	a,
		qreal	hl,
		qreal	hw,
		QPen &	pen,
		QGraphicsItem *	parent = nullptr )

Creates an arrow as a QGraphicItem.

Parameters

l	Length of the arrow
a	Orientation of the arrow
hl	Length of the arrow head
hw	Width of the arrow head
pen	The pen for drawing the arrow
parent	The parent QGraphicsItem.

Definition at line 19 of file QArrow.cpp.

    : QGraphicsItem(parent)
{
    _arrowLength = l;
    _arrowAngle = a;
    _headLength = hl;
    _headWidth = hw;
    _arrowPen = pen;
}

References _arrowAngle, _arrowLength, _arrowPen, _headLength, and _headWidth.

QArrow() [2/2]

QArrow::QArrow	(	qreal	l,
		qreal	a,
		QPen &	pen,
		QGraphicsItem *	parent = nullptr )

Creates an arrow as a QGraphicItem. Length and width of the arrow head are given by default values.

Parameters

l	Length of the arrow
a	Orientation of the arrow
pen	The pen for drawing the arrow
parent	The parent QGraphicsItem.

Definition at line 36 of file QArrow.cpp.

    : QGraphicsItem(parent)
{
    _arrowLength = l;
    _arrowAngle = a;
    _headLength = 8;  // default headlength
    _headWidth = 5;   // default headwidth
    _arrowPen = pen;
}

References _arrowAngle, _arrowLength, _arrowPen, _headLength, and _headWidth.

~QArrow()

QArrow::~QArrow ( )

overridedefault

Member Function Documentation

boundingRect()

QRectF QArrow::boundingRect ( ) const

override

The bounding box of the arrow.

Definition at line 59 of file QArrow.cpp.

{
    double deltaX = cos(_arrowAngle) * _arrowLength;
    double deltaY = sin(_arrowAngle) * _arrowLength;
 
    return QRectF(0, 0, deltaX, deltaY);
}

References _arrowAngle, and _arrowLength.

calcCos()

double QArrow::calcCos ( double angle )

private

Definition at line 48 of file QArrow.cpp.

{
    return cos(angle * PI / 180);
}

References PI.

Referenced by paint().

calcSin()

double QArrow::calcSin ( double angle )

private

Definition at line 53 of file QArrow.cpp.

{
    return sin(angle * PI / 180);
}

References PI.

Referenced by paint().

getAngle()

double QArrow::getAngle

(

)

Returns the orientation of the arrow.

Definition at line 74 of file QArrow.cpp.

{
    return _arrowAngle;
}

References _arrowAngle.

getLength()

double QArrow::getLength

(

)

Returns the length of the arrow.

Definition at line 68 of file QArrow.cpp.

{
    return _arrowLength;
}

References _arrowLength.

paint()

void QArrow::paint ( QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * widget )

override

Overloaded paint-method from QGraphicsItem. Basically it draws a line with an arrowhead consisting of two short lines at the end

Definition at line 84 of file QArrow.cpp.

{
    Q_UNUSED(option)
    Q_UNUSED(widget)
 
    double ddeltaX = calcCos(_arrowAngle) * _arrowLength;
    double ddeltaY = calcSin(_arrowAngle) * _arrowLength;
    double theta = atan(ddeltaY / ddeltaX);
    double theta2 = (ddeltaX < 0.0) ? (theta + PI) : theta;
    int lengthdeltaX = -static_cast<int>(cos(theta2) * _headLength);
    int lengthdeltaY = -static_cast<int>(sin(theta2) * _headLength);
    auto widthdeltaX = static_cast<int>(sin(theta2) * _headWidth);
    auto widthdeltaY = static_cast<int>(cos(theta2) * _headWidth);
    auto deltaX = static_cast<int>(ddeltaX);
    auto deltaY = static_cast<int>(ddeltaY);
    painter->setPen(_arrowPen);
    painter->drawLine(0, 0, deltaX, deltaY);
    painter->drawLine(deltaX,
                      deltaY,
                      deltaX + lengthdeltaX + widthdeltaX,
                      deltaY + lengthdeltaY - widthdeltaY);
    painter->drawLine(deltaX,
                      deltaY,
                      deltaX + lengthdeltaX - widthdeltaX,
                      deltaY + lengthdeltaY + widthdeltaY);
}

References _arrowAngle, _arrowLength, _arrowPen, _headLength, _headWidth, calcCos(), calcSin(), and PI.

setAngle()

void QArrow::setAngle

(

qreal

a

)

Changes orientation of the arrow.

Definition at line 113 of file QArrow.cpp.

{
    _arrowAngle = a;
}

References _arrowAngle.

setLength()

void QArrow::setLength

(

qreal

l

)

Changes the length of the arrow.

Definition at line 119 of file QArrow.cpp.

{
    _arrowLength = l;
}

References _arrowLength.

Member Data Documentation

_arrowAngle

qreal QArrow::_arrowAngle

private

Definition at line 35 of file QArrow.h.

Referenced by QArrow(), QArrow(), boundingRect(), getAngle(), paint(), and setAngle().

_arrowLength

qreal QArrow::_arrowLength

private

Definition at line 34 of file QArrow.h.

Referenced by QArrow(), QArrow(), boundingRect(), getLength(), paint(), and setLength().

_arrowPen

QPen QArrow::_arrowPen

private

Definition at line 38 of file QArrow.h.

Referenced by QArrow(), QArrow(), and paint().

_headLength

qreal QArrow::_headLength

private

Definition at line 36 of file QArrow.h.

Referenced by QArrow(), QArrow(), and paint().

_headWidth

qreal QArrow::_headWidth

private

Definition at line 37 of file QArrow.h.

Referenced by QArrow(), QArrow(), and paint().

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The documentation for this class was generated from the following files:

• QArrow.h
• QArrow.cpp