QwtCompassMagnetNeedle Class Reference

A magnet needle for compass widgets. More...

#include <qwt_dial_needle.h>

Inheritance diagram for QwtCompassMagnetNeedle:

Collaboration diagram for QwtCompassMagnetNeedle:

List of all members.

Public Types
enum	Style { TriangleStyle, ThinStyle }
	Style of the needle. More...
Public Member Functions
	QwtCompassMagnetNeedle (Style=TriangleStyle, const QColor &light=Qt::white, const QColor &dark=Qt::red)
	Constructor.
virtual void	draw (QPainter *, const QPoint &, int length, double direction, QPalette::ColorGroup=QPalette::Active) const
Static Public Member Functions
static void	drawTriangleNeedle (QPainter *, const QPalette &, QPalette::ColorGroup, const QPoint &, int length, double direction)
static void	drawThinNeedle (QPainter *, const QPalette &, QPalette::ColorGroup, const QPoint &, int length, double direction)
Static Protected Member Functions
static void	drawPointer (QPainter *painter, const QBrush &brush, int colorOffset, const QPoint &center, int length, int width, double direction)

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Detailed Description

A magnet needle for compass widgets.

A magnet needle points to two opposite directions indicating north and south.

The following colors are used:

• QColorGroup::Light
  Used for pointing south
• QColorGroup::Dark
  Used for pointing north
• QColorGroup::Base
  Knob (ThinStyle only)

See also:

QwtDial, QwtCompass

Definition at line 125 of file qwt_dial_needle.h.

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Member Enumeration Documentation

enum QwtCompassMagnetNeedle::Style

Style of the needle.

Enumerator:

TriangleStyle
ThinStyle

Definition at line 129 of file qwt_dial_needle.h.

    {
        TriangleStyle,
        ThinStyle
    };

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Constructor & Destructor Documentation

QwtCompassMagnetNeedle::QwtCompassMagnetNeedle	(	Style	style = TriangleStyle,
		const QColor &	light = Qt::white,
		const QColor &	dark = Qt::red
	)

Constructor.

Definition at line 293 of file qwt_dial_needle.cpp.

References QwtDialNeedle::palette(), and QwtDialNeedle::setPalette().

                                                :
    d_style(style)
{   
    QPalette palette;
    for ( int i = 0; i < QPalette::NColorGroups; i++ )
    {
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Light, light);
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Dark, dark);
        palette.setColor((QPalette::ColorGroup)i,
            QwtPalette::Base, Qt::darkGray);
    }

    setPalette(palette); 
}

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Member Function Documentation

void QwtCompassMagnetNeedle::draw	(	QPainter *	painter,
		const QPoint &	center,
		int	length,
		double	direction,
		QPalette::ColorGroup	colorGroup = QPalette::Active
	)		const [virtual]

Draw the needle

Parameters:

painter	Painter
center	Center of the dial, start position for the needle
length	Length of the needle
direction	Direction of the needle, in degrees counter clockwise
colorGroup	Color group, used for painting

Implements QwtDialNeedle.

Definition at line 320 of file qwt_dial_needle.cpp.

References drawThinNeedle(), drawTriangleNeedle(), QwtDialNeedle::palette(), and ThinStyle.

{
    if ( d_style == ThinStyle )
    {
        drawThinNeedle(painter, palette(), colorGroup, 
            center, length, direction); 
    }
    else
    {
        drawTriangleNeedle(painter, palette(), colorGroup,
            center, length, direction);
    }
}

void QwtCompassMagnetNeedle::drawPointer	(	QPainter *	painter,
		const QBrush &	brush,
		int	colorOffset,
		const QPoint &	center,
		int	length,
		int	width,
		double	direction
	)		[static, protected]

Draw a compass needle

Parameters:

painter	Painter
brush	Brush
colorOffset	Color offset
center	Center, where the needle starts
length	Length of the needle
width	Width of the needle
direction	Direction

Definition at line 447 of file qwt_dial_needle.cpp.

References qwtDegree2Pos(), and qwtMax.

Referenced by drawThinNeedle().

{
    painter->save();

    const int peak = qwtMax(qRound(length / 10.0), 5);

    const int knobWidth = width + 8;
    QRect knobRect(0, 0, knobWidth, knobWidth);
    knobRect.moveCenter(center);

    QwtPolygon pa(5);

    pa.setPoint(0, qwtDegree2Pos(center, width / 2, direction + 90.0));
    pa.setPoint(1, center);
    pa.setPoint(2, qwtDegree2Pos(pa.point(1), length - peak, direction));
    pa.setPoint(3, qwtDegree2Pos(center, length, direction));
    pa.setPoint(4, qwtDegree2Pos(pa.point(0), length - peak, direction));

    painter->setPen(Qt::NoPen);

    QBrush darkBrush = brush;
    darkBrush.setColor(darkBrush.color().dark(100 + colorOffset));
    painter->setBrush(darkBrush);
    painter->drawPolygon(pa);
    painter->drawPie(knobRect, qRound(direction * 16), 90 * 16);

    pa.setPoint(0, qwtDegree2Pos(center, width / 2, direction - 90.0));
    pa.setPoint(4, qwtDegree2Pos(pa.point(0), length - peak, direction));

    QBrush lightBrush = brush;
    lightBrush.setColor(lightBrush.color().dark(100 - colorOffset));
    painter->setBrush(lightBrush);
    painter->drawPolygon(pa);
    painter->drawPie(knobRect, qRound(direction * 16), -90 * 16);

    painter->restore();
}

void QwtCompassMagnetNeedle::drawThinNeedle	(	QPainter *	painter,
		const QPalette &	palette,
		QPalette::ColorGroup	colorGroup,
		const QPoint &	center,
		int	length,
		double	direction
	)		[static]

Draw a compass needle

Parameters:

painter	Painter
palette	Palette
colorGroup	Color group
center	Center, where the needle starts
length	Length of the needle
direction	Direction

Definition at line 411 of file qwt_dial_needle.cpp.

References QwtDialNeedle::drawKnob(), drawPointer(), and qwtMax.

Referenced by draw().

{
    const QBrush darkBrush = palette.brush(colorGroup, QwtPalette::Dark);
    const QBrush lightBrush = palette.brush(colorGroup, QwtPalette::Light);
    const QBrush baseBrush = palette.brush(colorGroup, QwtPalette::Base);

    const int colorOffset = 10;
    const int width = qwtMax(qRound(length / 6.0), 3);

    painter->save();

    const QPoint arrowCenter(center.x() + 1, center.y() + 1);

    drawPointer(painter, darkBrush, colorOffset, 
        arrowCenter, length, width, direction);
    drawPointer(painter, lightBrush, -colorOffset, 
        arrowCenter, length, width, direction + 180.0);
    
    drawKnob(painter, arrowCenter, width, baseBrush, true);

    painter->restore();
}

void QwtCompassMagnetNeedle::drawTriangleNeedle	(	QPainter *	painter,
		const QPalette &	palette,
		QPalette::ColorGroup	colorGroup,
		const QPoint &	center,
		int	length,
		double	direction
	)		[static]

Draw a compass needle

Parameters:

painter	Painter
palette	Palette
colorGroup	Color group
center	Center, where the needle starts
length	Length of the needle
direction	Direction

Definition at line 345 of file qwt_dial_needle.cpp.

References qwtDegree2Pos().

Referenced by draw().

{
    const QBrush darkBrush = palette.brush(colorGroup, QwtPalette::Dark);
    const QBrush lightBrush = palette.brush(colorGroup, QwtPalette::Light);

    QBrush brush;

    const int width = qRound(length / 3.0);
    const int colorOffset =  10;

    painter->save();
    painter->setPen(Qt::NoPen);

    const QPoint arrowCenter(center.x() + 1, center.y() + 1);

    QwtPolygon pa(3);
    pa.setPoint(0, arrowCenter);
    pa.setPoint(1, qwtDegree2Pos(arrowCenter, length, direction));

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction + 90.0));

    brush = darkBrush;
    brush.setColor(brush.color().dark(100 + colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction - 90.0));

    brush = darkBrush;
    brush.setColor(brush.color().dark(100 - colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    // --

    pa.setPoint(1, qwtDegree2Pos(arrowCenter, length, direction + 180.0));

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction + 90.0));

    brush = lightBrush;
    brush.setColor(brush.color().dark(100 + colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    pa.setPoint(2, qwtDegree2Pos(arrowCenter, width / 2, direction - 90.0));

    brush = lightBrush;
    brush.setColor(brush.color().dark(100 - colorOffset));
    painter->setBrush(brush);
    painter->drawPolygon(pa);

    painter->restore();
}

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

• qwt_dial_needle.h
• qwt_dial_needle.cpp