qwt_round_scale_draw.cpp

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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * 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_round_scale_draw.h"
#include "qwt_painter.h"
#include "qwt_scale_div.h"
#include "qwt_scale_map.h"
#include "qwt_math.h"
#include <qpen.h>
#include <qpainter.h>
#include <qfontmetrics.h>
#include <qmath.h>

class QwtRoundScaleDraw::PrivateData
{
public:
    PrivateData():
        center( 50.0, 50.0 ),
        radius( 50.0 ),
        startAngle( -135.0 ),
        endAngle( 135.0 )
    {
    }

    QPointF center;
    double radius;

    double startAngle;
    double endAngle;
};

QwtRoundScaleDraw::QwtRoundScaleDraw()
{
    d_data = new QwtRoundScaleDraw::PrivateData;

    setRadius( 50 );
    scaleMap().setPaintInterval( d_data->startAngle, d_data->endAngle );
}

QwtRoundScaleDraw::~QwtRoundScaleDraw()
{
    delete d_data;
}

void QwtRoundScaleDraw::setRadius( double radius )
{
    d_data->radius = radius;
}

double QwtRoundScaleDraw::radius() const
{
    return d_data->radius;
}

void QwtRoundScaleDraw::moveCenter( const QPointF &center )
{
    d_data->center = center;
}

QPointF QwtRoundScaleDraw::center() const
{
    return d_data->center;
}

void QwtRoundScaleDraw::setAngleRange( double angle1, double angle2 )
{
#if 0
    angle1 = qBound( -360.0, angle1, 360.0 );
    angle2 = qBound( -360.0, angle2, 360.0 );
#endif

    d_data->startAngle = angle1;
    d_data->endAngle = angle2;

    if ( d_data->startAngle == d_data->endAngle )
    {
        d_data->startAngle -= 1;
        d_data->endAngle += 1;
    }

    scaleMap().setPaintInterval( d_data->startAngle, d_data->endAngle );
}

void QwtRoundScaleDraw::drawLabel( QPainter *painter, double value ) const
{
    const double tval = scaleMap().transform( value );
    if ( ( tval >= d_data->startAngle + 360.0 )
        || ( tval <= d_data->startAngle - 360.0 ) )
    {
        return;
    }

    const QwtText label = tickLabel( painter->font(), value );
    if ( label.isEmpty() )
        return;

    double radius = d_data->radius;
    if ( hasComponent( QwtAbstractScaleDraw::Ticks ) ||
        hasComponent( QwtAbstractScaleDraw::Backbone ) )
    {
        radius += spacing();
    }

    if ( hasComponent( QwtAbstractScaleDraw::Ticks ) )
        radius += tickLength( QwtScaleDiv::MajorTick );

    const QSizeF sz = label.textSize( painter->font() );
    const double arc = qwtRadians( tval );

    const double x = d_data->center.x() +
        ( radius + sz.width() / 2.0 ) * qSin( arc );
    const double y = d_data->center.y() -
        ( radius + sz.height() / 2.0 ) * qCos( arc );

    const QRectF r( x - sz.width() / 2, y - sz.height() / 2,
        sz.width(), sz.height() );
    label.draw( painter, r );
}

void QwtRoundScaleDraw::drawTick( QPainter *painter, double value, double len ) const
{
    if ( len <= 0 )
        return;

    const double tval = scaleMap().transform( value );

    const double cx = d_data->center.x();
    const double cy = d_data->center.y();
    const double radius = d_data->radius;

    if ( ( tval < d_data->startAngle + 360.0 )
        && ( tval > d_data->startAngle - 360.0 ) )
    {
        const double arc = qwtRadians( tval );

        const double sinArc = qSin( arc );
        const double cosArc = qCos( arc );

        const double x1 = cx + radius * sinArc;
        const double x2 = cx + ( radius + len ) * sinArc;
        const double y1 = cy - radius * cosArc;
        const double y2 = cy - ( radius + len ) * cosArc;

        QwtPainter::drawLine( painter, x1, y1, x2, y2 );
    }
}

void QwtRoundScaleDraw::drawBackbone( QPainter *painter ) const
{
    const double deg1 = scaleMap().p1();
    const double deg2 = scaleMap().p2();

    const int a1 = qRound( qMin( deg1, deg2 ) - 90 );
    const int a2 = qRound( qMax( deg1, deg2 ) - 90 );

    const double radius = d_data->radius;
    const double x = d_data->center.x() - radius;
    const double y = d_data->center.y() - radius;

    painter->drawArc( QRectF( x, y, 2 * radius, 2 * radius ),
        -a2 * 16, ( a2 - a1 + 1 ) * 16 );          // counterclockwise
}

double QwtRoundScaleDraw::extent( const QFont &font ) const
{
    double d = 0.0;

    if ( hasComponent( QwtAbstractScaleDraw::Labels ) )
    {
        const QwtScaleDiv &sd = scaleDiv();
        const QList<double> &ticks = sd.ticks( QwtScaleDiv::MajorTick );
        for ( int i = 0; i < ticks.count(); i++ )
        {
            const double value = ticks[i];
            if ( !sd.contains( value ) )
                continue;

            const double tval = scaleMap().transform( value );
            if ( ( tval < d_data->startAngle + 360 )
                && ( tval > d_data->startAngle - 360 ) )
            {
                const QwtText label = tickLabel( font, value );
                if ( label.isEmpty() )
                    continue;

                const double arc = qwtRadians( tval );

                const QSizeF sz = label.textSize( font );
                const double off = qMax( sz.width(), sz.height() );

                double x = off * qSin( arc );
                double y = off * qCos( arc );

                const double dist = qSqrt( x * x + y * y );
                if ( dist > d )
                    d = dist;
            }
        }
    }

    if ( hasComponent( QwtAbstractScaleDraw::Ticks ) )
    {
        d += maxTickLength();
    }

    if ( hasComponent( QwtAbstractScaleDraw::Backbone ) )
    {
        const double pw = qMax( 1, penWidth() );  // pen width can be zero
        d += pw;
    }

    if ( hasComponent( QwtAbstractScaleDraw::Labels ) &&
        ( hasComponent( QwtAbstractScaleDraw::Ticks ) ||
            hasComponent( QwtAbstractScaleDraw::Backbone ) ) )
    {
        d += spacing();
    }

    d = qMax( d, minimumExtent() );

    return d;
}