qwt_compass_rose.cpp

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/******************************************************************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/
 
#include "qwt_compass_rose.h"
#include "qwt_point_polar.h"
 
#include <qpainter.h>
#include <qpainterpath.h>
 
static QPointF qwtIntersection(
    QPointF p11, QPointF p12, QPointF p21, QPointF p22 )
{
    const QLineF line1( p11, p12 );
    const QLineF line2( p21, p22 );
 
    QPointF pos;
#if QT_VERSION >= 0x050e00
    if ( line1.intersects( line2, &pos ) == QLineF::NoIntersection )
#else
    if ( line1.intersect( line2, &pos ) == QLineF::NoIntersection )
#endif
        return QPointF();
 
    return pos;
}
 
QwtCompassRose::QwtCompassRose()
{
}
 
QwtCompassRose::~QwtCompassRose()
{
}
 
void QwtCompassRose::setPalette( const QPalette& p )
{
    m_palette = p;
}
 
const QPalette& QwtCompassRose::palette() const
{
    return m_palette;
}
 
class QwtSimpleCompassRose::PrivateData
{
  public:
    PrivateData()
        : width( 0.2 )
        , numThorns( 8 )
        , numThornLevels( -1 )
        , shrinkFactor( 0.9 )
    {
    }
 
    double width;
    int numThorns;
    int numThornLevels;
    double shrinkFactor;
};
 
QwtSimpleCompassRose::QwtSimpleCompassRose(
    int numThorns, int numThornLevels )
{
    m_data = new PrivateData();
    m_data->numThorns = numThorns;
    m_data->numThornLevels = numThornLevels;
 
    const QColor dark( 128, 128, 255 );
    const QColor light( 192, 255, 255 );
 
    QPalette palette;
    palette.setColor( QPalette::Dark, dark );
    palette.setColor( QPalette::Light, light );
 
    setPalette( palette );
}
 
QwtSimpleCompassRose::~QwtSimpleCompassRose()
{
    delete m_data;
}
 
void QwtSimpleCompassRose::setShrinkFactor( double factor )
{
    m_data->shrinkFactor = factor;
}
 
double QwtSimpleCompassRose::shrinkFactor() const
{
    return m_data->shrinkFactor;
}
 
void QwtSimpleCompassRose::draw( QPainter* painter, const QPointF& center,
    double radius, double north, QPalette::ColorGroup cg ) const
{
    QPalette pal = palette();
    pal.setCurrentColorGroup( cg );
 
    drawRose( painter, pal, center, radius, north, m_data->width,
        m_data->numThorns, m_data->numThornLevels, m_data->shrinkFactor );
}
 
void QwtSimpleCompassRose::drawRose(
    QPainter* painter,
    const QPalette& palette,
    const QPointF& center, double radius, double north, double width,
    int numThorns, int numThornLevels, double shrinkFactor )
{
    if ( numThorns < 4 )
        numThorns = 4;
 
    if ( numThorns % 4 )
        numThorns += 4 - numThorns % 4;
 
    if ( numThornLevels <= 0 )
        numThornLevels = numThorns / 4;
 
    if ( shrinkFactor >= 1.0 )
        shrinkFactor = 1.0;
 
    if ( shrinkFactor <= 0.5 )
        shrinkFactor = 0.5;
 
    painter->save();
 
    painter->setPen( Qt::NoPen );
 
    for ( int j = 1; j <= numThornLevels; j++ )
    {
        double step = std::pow( 2.0, j ) * M_PI / numThorns;
        if ( step > M_PI_2 )
            break;
 
        double r = radius;
        for ( int k = 0; k < 3; k++ )
        {
            if ( j + k < numThornLevels )
                r *= shrinkFactor;
        }
 
        double leafWidth = r * width;
        if ( 2.0 * M_PI / step > 32 )
            leafWidth = 16;
 
        const double origin = qwtRadians( north );
        for ( double angle = origin;
            angle < 2.0 * M_PI + origin; angle += step )
        {
            const QPointF p = qwtPolar2Pos( center, r, angle );
            const QPointF p1 = qwtPolar2Pos( center, leafWidth, angle + M_PI_2 );
            const QPointF p2 = qwtPolar2Pos( center, leafWidth, angle - M_PI_2 );
            const QPointF p3 = qwtPolar2Pos( center, r, angle + step / 2.0 );
            const QPointF p4 = qwtPolar2Pos( center, r, angle - step / 2.0 );
 
            QPainterPath darkPath;
            darkPath.moveTo( center );
            darkPath.lineTo( p );
            darkPath.lineTo( qwtIntersection( center, p3, p1, p ) );
 
            painter->setBrush( palette.brush( QPalette::Dark ) );
            painter->drawPath( darkPath );
 
            QPainterPath lightPath;
            lightPath.moveTo( center );
            lightPath.lineTo( p );
            lightPath.lineTo( qwtIntersection( center, p4, p2, p ) );
 
            painter->setBrush( palette.brush( QPalette::Light ) );
            painter->drawPath( lightPath );
        }
    }
    painter->restore();
}
 
void QwtSimpleCompassRose::setWidth( double width )
{
    m_data->width = width;
    if ( m_data->width < 0.03 )
        m_data->width = 0.03;
 
    if ( m_data->width > 0.4 )
        m_data->width = 0.4;
}
 
double QwtSimpleCompassRose::width() const
{
    return m_data->width;
}
 
void QwtSimpleCompassRose::setNumThorns( int numThorns )
{
    if ( numThorns < 4 )
        numThorns = 4;
 
    if ( numThorns % 4 )
        numThorns += 4 - numThorns % 4;
 
    m_data->numThorns = numThorns;
}
 
int QwtSimpleCompassRose::numThorns() const
{
    return m_data->numThorns;
}
 
void QwtSimpleCompassRose::setNumThornLevels( int numThornLevels )
{
    m_data->numThornLevels = numThornLevels;
}
 
int QwtSimpleCompassRose::numThornLevels() const
{
    return m_data->numThornLevels;
}