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qwt_compass_rose.cpp

00001 /* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
00002  * Qwt Widget Library
00003  * Copyright (C) 1997   Josef Wilgen
00004  * Copyright (C) 2002   Uwe Rathmann
00005  *
00006  * This library is free software; you can redistribute it and/or
00007  * modify it under the terms of the Qwt License, Version 1.0
00008  *****************************************************************************/
00009 
00010 #include <math.h>
00011 #include <qpainter.h>
00012 #include "qwt_math.h"
00013 #include "qwt_painter.h"
00014 #include "qwt_compass_rose.h"
00015 
00016 static QPoint cutPoint(QPoint p11, QPoint p12, QPoint p21, QPoint p22)
00017 {
00018     double dx1 = p12.x() - p11.x();
00019     double dy1 = p12.y() - p11.y();
00020     double dx2 = p22.x() - p21.x();
00021     double dy2 = p22.y() - p21.y();
00022 
00023     if ( dx1 == 0.0 && dx2 == 0.0 )
00024         return QPoint();
00025 
00026     if ( dx1 == 0.0 )
00027     {
00028         const double m = dy2 / dx2;
00029         const double t = p21.y() - m * p21.x();
00030         return QPoint(p11.x(), qwtInt(m * p11.x() + t));
00031     }
00032 
00033     if ( dx2 == 0 )
00034     {
00035         const double m = dy1 / dx1;
00036         const double t = p11.y() - m * p11.x();
00037         return QPoint(p21.x(), qwtInt(m * p21.x() + t));
00038     }
00039 
00040     const double m1 = dy1 / dx1;
00041     const double t1 = p11.y() - m1 * p11.x();
00042 
00043     const double m2 = dy2 / dx2;
00044     const double t2 = p21.y() - m2 * p21.x();
00045 
00046     if ( m1 == m2 )
00047         return QPoint();
00048 
00049     const double x = ( t2 - t1 ) / ( m1 - m2 );
00050     const double y = t1 + m1 * x;
00051 
00052     return QPoint(qwtInt(x), qwtInt(y));
00053 }
00054 
00055 QwtSimpleCompassRose::QwtSimpleCompassRose(int numThorns, int numThornLevels):
00056     d_width(0.2),
00057     d_numThorns(numThorns),
00058     d_numThornLevels(numThornLevels),
00059     d_shrinkFactor(0.9)
00060 {
00061     const QColor dark(128,128,255);
00062     const QColor light(192,255,255);
00063     
00064     QPalette palette;
00065     for ( int i = 0; i < QPalette::NColorGroups; i++ )
00066     {
00067         palette.setColor((QPalette::ColorGroup)i,
00068             QColorGroup::Dark, dark);
00069         palette.setColor((QPalette::ColorGroup)i,
00070             QColorGroup::Light, light);
00071     }
00072 
00073     setPalette(palette);
00074 }
00075 
00076 void QwtSimpleCompassRose::draw(QPainter *painter, const QPoint &center, 
00077     int radius, double north, QPalette::ColorGroup cg) const
00078 {
00079     QColorGroup colorGroup;
00080     switch(cg)
00081     {
00082         case QPalette::Disabled:
00083             colorGroup = palette().disabled();
00084         case QPalette::Inactive:
00085             colorGroup = palette().inactive();
00086         default:
00087             colorGroup = palette().active();
00088     }
00089 
00090     drawRose(painter, colorGroup, center, radius, north, d_width, 
00091         d_numThorns, d_numThornLevels, d_shrinkFactor);
00092 }
00093 
00094 void QwtSimpleCompassRose::drawRose(
00095     QPainter *painter, const QColorGroup &cg,
00096     const QPoint &center, int radius, double north, double width,
00097     int numThorns, int numThornLevels, double shrinkFactor)
00098 {
00099     if ( numThorns < 4 )
00100         numThorns = 4;
00101 
00102     if ( numThorns % 4 )
00103         numThorns += 4 - numThorns % 4;
00104 
00105     if ( numThornLevels <= 0 )
00106         numThornLevels = numThorns / 4;
00107 
00108     if ( shrinkFactor >= 1.0 )
00109         shrinkFactor = 1.0;
00110 
00111     if ( shrinkFactor <= 0.5 )
00112         shrinkFactor = 0.5;
00113 
00114     painter->save();
00115 
00116     painter->setPen(Qt::NoPen);
00117 
00118     for ( int j = 1; j <= numThornLevels; j++ )
00119     {
00120         double step =  pow(2.0, j) * M_PI / (double)numThorns;
00121         if ( step > M_PI_2 )
00122             break;
00123 
00124         double r = radius;
00125         for ( int k = 0; k < 3; k++ )
00126         {
00127             if ( j + k < numThornLevels )
00128                 r *= shrinkFactor;
00129         }
00130 
00131         double leafWidth = r * width;
00132         if ( 2.0 * M_PI / step > 32 )
00133             leafWidth = 16;
00134 
00135         const double origin = north / 180.0 * M_PI;
00136         for ( double angle = origin; 
00137             angle < 2.0 * M_PI + origin; angle += step)
00138         {
00139             const QPoint p = qwtPolar2Pos(center, r, angle);
00140             QPoint p1 = qwtPolar2Pos(center, leafWidth, angle + M_PI_2);
00141             QPoint p2 = qwtPolar2Pos(center, leafWidth, angle - M_PI_2);
00142 
00143             QPointArray pa(3);
00144             pa.setPoint(0, center);
00145             pa.setPoint(1, p);
00146 
00147             QPoint p3 = qwtPolar2Pos(center, r, angle + step / 2.0);
00148             p1 = cutPoint(center, p3, p1, p);
00149             pa.setPoint(2, p1);
00150             painter->setBrush(cg.brush(QColorGroup::Dark));
00151             painter->drawPolygon(pa);
00152 
00153             QPoint p4 = qwtPolar2Pos(center, r, angle - step / 2.0);
00154             p2 = cutPoint(center, p4, p2, p);
00155 
00156             pa.setPoint(2, p2);
00157             painter->setBrush(cg.brush(QColorGroup::Light));
00158             painter->drawPolygon(pa);
00159         }
00160     }
00161     painter->restore();
00162 }
00163 
00169 void QwtSimpleCompassRose::setWidth(double w) 
00170 {
00171    d_width = w;
00172    if (d_width < 0.03) 
00173         d_width = 0.03;
00174 
00175    if (d_width > 0.4) 
00176         d_width = 0.4;
00177 }
00178 
00179 void QwtSimpleCompassRose::setNumThorns(int numThorns) 
00180 {
00181     if ( numThorns < 4 )
00182         numThorns = 4;
00183 
00184     if ( numThorns % 4 )
00185         numThorns += 4 - numThorns % 4;
00186 
00187     d_numThorns = numThorns;
00188 }
00189 
00190 int QwtSimpleCompassRose::numThorns() const
00191 {
00192    return d_numThorns;
00193 }
00194 
00195 void QwtSimpleCompassRose::setNumThornLevels(int numThornLevels) 
00196 {
00197     d_numThornLevels = numThornLevels;
00198 }
00199 
00200 int QwtSimpleCompassRose::numThornLevels() const
00201 {
00202     return d_numThornLevels;
00203 }

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