qwt_dial.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_dial.h"
#include "qwt_dial_needle.h"
#include "qwt_math.h"
#include "qwt_scale_engine.h"
#include "qwt_scale_map.h"
#include "qwt_round_scale_draw.h"
#include "qwt_painter.h"
#include <qpainter.h>
#include <qpalette.h>
#include <qpixmap.h>
#include <qevent.h>
#include <qalgorithms.h>
#include <qmath.h>
#include <qstyle.h>
#include <qstyleoption.h>
#include <qapplication.h>

static inline double qwtAngleDist( double a1, double a2 )
{
    double dist = qAbs( a2 - a1 );
    if ( dist > 360.0 )
        dist -= 360.0;

    return dist;
}

static inline bool qwtIsOnArc( double angle, double min, double max )
{
    if ( min < max )
    {
        return ( angle >= min ) && ( angle <= max );
    }
    else
    {
        return ( angle >= min ) || ( angle <= max );
    }
}

static inline double qwtBoundedAngle( double min, double angle, double max )
{
    double from = qwtNormalizeDegrees( min );
    double to = qwtNormalizeDegrees( max );

    double a;

    if ( qwtIsOnArc( angle, from, to ) )
    {
        a = angle;
        if ( a < min )
            a += 360.0;
    }
    else
    {
        if ( qwtAngleDist( angle, from ) <
            qwtAngleDist( angle, to ) )
        {
            a = min;
        }
        else
        {
            a = max;
        }
    }

    return a;
}

class QwtDial::PrivateData
{
public:
    PrivateData():
        frameShadow( Sunken ),
        lineWidth( 0 ),
        mode( RotateNeedle ),
        origin( 90.0 ),
        minScaleArc( 0.0 ),
        maxScaleArc( 0.0 ),
        needle( NULL ),
        arcOffset( 0.0 ),
        mouseOffset( 0.0 )
    {
    }

    ~PrivateData()
    {
        delete needle;
    }
    Shadow frameShadow;
    int lineWidth;

    QwtDial::Mode mode;

    double origin;
    double minScaleArc;
    double maxScaleArc;

    QwtDialNeedle *needle;

    double arcOffset;
    double mouseOffset;

    QPixmap pixmapCache;
};

QwtDial::QwtDial( QWidget* parent ):
    QwtAbstractSlider( parent )
{
    d_data = new PrivateData;

    setFocusPolicy( Qt::TabFocus );

    QPalette p = palette();
    for ( int i = 0; i < QPalette::NColorGroups; i++ )
    {
        const QPalette::ColorGroup colorGroup =
            static_cast<QPalette::ColorGroup>( i );

        // Base: background color of the circle inside the frame.
        // WindowText: background color of the circle inside the scale

        p.setColor( colorGroup, QPalette::WindowText,
            p.color( colorGroup, QPalette::Base ) );
    }
    setPalette( p );

    QwtRoundScaleDraw* scaleDraw = new QwtRoundScaleDraw();
    scaleDraw->setRadius( 0 );

    setScaleDraw( scaleDraw );

    setScaleArc( 0.0, 360.0 ); // scale as a full circle

    setScaleMaxMajor( 10 );
    setScaleMaxMinor( 5 );

    setValue( 0.0 );
}

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

void QwtDial::setFrameShadow( Shadow shadow )
{
    if ( shadow != d_data->frameShadow )
    {
        invalidateCache();

        d_data->frameShadow = shadow;
        if ( lineWidth() > 0 )
            update();
    }
}

QwtDial::Shadow QwtDial::frameShadow() const
{
    return d_data->frameShadow;
}

void QwtDial::setLineWidth( int lineWidth )
{
    if ( lineWidth < 0 )
        lineWidth = 0;

    if ( d_data->lineWidth != lineWidth )
    {
        invalidateCache();

        d_data->lineWidth = lineWidth;
        update();
    }
}

int QwtDial::lineWidth() const
{
    return d_data->lineWidth;
}

QRect QwtDial::innerRect() const
{
    const int lw = lineWidth();
    return boundingRect().adjusted( lw, lw, -lw, -lw );
}

QRect QwtDial::boundingRect() const
{
    const QRect cr = contentsRect();

    const double dim = qMin( cr.width(), cr.height() );

    QRect inner( 0, 0, dim, dim );
    inner.moveCenter( cr.center() );

    return inner;
}

QRect QwtDial::scaleInnerRect() const
{
    QRect rect = innerRect();

    const QwtAbstractScaleDraw *sd = scaleDraw();
    if ( sd )
    {
        int scaleDist = qCeil( sd->extent( font() ) );
        scaleDist++; // margin

        rect.adjust( scaleDist, scaleDist, -scaleDist, -scaleDist );
    }

    return rect;
}

void QwtDial::setMode( Mode mode )
{
    if ( mode != d_data->mode )
    {
        invalidateCache();

        d_data->mode = mode;
        sliderChange();
    }
}

QwtDial::Mode QwtDial::mode() const
{
    return d_data->mode;
}

void QwtDial::invalidateCache()
{
    d_data->pixmapCache = QPixmap();
}

void QwtDial::paintEvent( QPaintEvent *event )
{
    QPainter painter( this );
    painter.setClipRegion( event->region() );

    QStyleOption opt;
    opt.init(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this);

    if ( d_data->mode == QwtDial::RotateScale )
    {
        painter.save();
        painter.setRenderHint( QPainter::Antialiasing, true );

        drawContents( &painter );

        painter.restore();
    }

    const QRect r = contentsRect();
    if ( r.size() != d_data->pixmapCache.size() )
    {
        d_data->pixmapCache = QwtPainter::backingStore( this, r.size() );
        d_data->pixmapCache.fill( Qt::transparent );

        QPainter p( &d_data->pixmapCache );
        p.setRenderHint( QPainter::Antialiasing, true );
        p.translate( -r.topLeft() );
            
        if ( d_data->mode != QwtDial::RotateScale )
            drawContents( &p );

        if ( lineWidth() > 0 )
            drawFrame( &p );

        if ( d_data->mode != QwtDial::RotateNeedle )
            drawNeedle( &p );
    }

    painter.drawPixmap( r.topLeft(), d_data->pixmapCache );

    if ( d_data->mode == QwtDial::RotateNeedle )
        drawNeedle( &painter );

    if ( hasFocus() )
        drawFocusIndicator( &painter );
}

void QwtDial::drawFocusIndicator( QPainter *painter ) const
{
    QwtPainter::drawFocusRect( painter, this, boundingRect() );
}

void QwtDial::drawFrame( QPainter *painter )
{
    QwtPainter::drawRoundFrame( painter, boundingRect(),
        palette(), lineWidth(), d_data->frameShadow );
}

void QwtDial::drawContents( QPainter *painter ) const
{
    if ( testAttribute( Qt::WA_NoSystemBackground ) ||
        palette().brush( QPalette::Base ) !=
            palette().brush( QPalette::Window ) )
    {
        const QRectF br = boundingRect();

        painter->save();
        painter->setPen( Qt::NoPen );
        painter->setBrush( palette().brush( QPalette::Base ) );
        painter->drawEllipse( br );
        painter->restore();
    }

    const QRectF insideScaleRect = scaleInnerRect();
    if ( palette().brush( QPalette::WindowText ) !=
            palette().brush( QPalette::Base ) )
    {
        painter->save();
        painter->setPen( Qt::NoPen );
        painter->setBrush( palette().brush( QPalette::WindowText ) );
        painter->drawEllipse( insideScaleRect );
        painter->restore();
    }

    const QPointF center = insideScaleRect.center();
    const double radius = 0.5 * insideScaleRect.width();

    painter->save();
    drawScale( painter, center, radius );
    painter->restore();

    painter->save();
    drawScaleContents( painter, center, radius );
    painter->restore();
}

void QwtDial::drawNeedle( QPainter *painter, const QPointF &center,
    double radius, double direction, QPalette::ColorGroup colorGroup ) const
{
    if ( d_data->needle )
    {
        direction = 360.0 - direction; // counter clockwise
        d_data->needle->draw( painter, center, radius, direction, colorGroup );
    }
}

void QwtDial::drawNeedle( QPainter *painter ) const
{
    if ( !isValid() )
        return;

    QPalette::ColorGroup colorGroup;
    if ( isEnabled() )
        colorGroup = hasFocus() ? QPalette::Active : QPalette::Inactive;
    else
        colorGroup = QPalette::Disabled;

    const QRectF sr = scaleInnerRect();

    painter->save();
    painter->setRenderHint( QPainter::Antialiasing, true );
    drawNeedle( painter, sr.center(), 0.5 * sr.width(),
        scaleMap().transform( value() ) + 270.0, colorGroup );
    painter->restore();
}

void QwtDial::drawScale( QPainter *painter, 
    const QPointF &center, double radius ) const
{
    QwtRoundScaleDraw *sd = const_cast<QwtRoundScaleDraw *>( scaleDraw() );
    if ( sd == NULL )
        return;

    sd->setRadius( radius );
    sd->moveCenter( center );

    QPalette pal = palette();

    const QColor textColor = pal.color( QPalette::Text );
    pal.setColor( QPalette::WindowText, textColor ); // ticks, backbone

    painter->setFont( font() );
    painter->setPen( QPen( textColor, sd->penWidth() ) );

    painter->setBrush( Qt::red );
    sd->draw( painter, pal );
}

void QwtDial::drawScaleContents( QPainter *painter,
    const QPointF &center, double radius ) const
{
    Q_UNUSED(painter);
    Q_UNUSED(center);
    Q_UNUSED(radius);
}

void QwtDial::setNeedle( QwtDialNeedle *needle )
{
    if ( needle != d_data->needle )
    {
        if ( d_data->needle )
            delete d_data->needle;

        d_data->needle = needle;
        update();
    }
}

const QwtDialNeedle *QwtDial::needle() const
{
    return d_data->needle;
}

QwtDialNeedle *QwtDial::needle()
{
    return d_data->needle;
}

QwtRoundScaleDraw *QwtDial::scaleDraw()
{
    return static_cast<QwtRoundScaleDraw *>( abstractScaleDraw() );
}

const QwtRoundScaleDraw *QwtDial::scaleDraw() const
{
    return static_cast<const QwtRoundScaleDraw *>( abstractScaleDraw() );
}

void QwtDial::setScaleDraw( QwtRoundScaleDraw *scaleDraw )
{
    setAbstractScaleDraw( scaleDraw );
    sliderChange();
}

void QwtDial::setScaleArc( double minArc, double maxArc )
{
    if ( minArc != 360.0 && minArc != -360.0 )
        minArc = ::fmod( minArc, 360.0 );
    if ( maxArc != 360.0 && maxArc != -360.0 )
        maxArc = ::fmod( maxArc, 360.0 );

    double minScaleArc = qMin( minArc, maxArc );
    double maxScaleArc = qMax( minArc, maxArc );

    if ( maxScaleArc - minScaleArc > 360.0 )
        maxScaleArc = minScaleArc + 360.0;

    if ( ( minScaleArc != d_data->minScaleArc ) || 
        ( maxScaleArc != d_data->maxScaleArc ) )
    {
        d_data->minScaleArc = minScaleArc;
        d_data->maxScaleArc = maxScaleArc;

        invalidateCache();
        sliderChange();
    }
}

void QwtDial::setMinScaleArc( double min )
{
    setScaleArc( min, d_data->maxScaleArc );
}

double QwtDial::minScaleArc() const
{
    return d_data->minScaleArc;
}

void QwtDial::setMaxScaleArc( double max )
{
    setScaleArc( d_data->minScaleArc, max );
}

double QwtDial::maxScaleArc() const
{
    return d_data->maxScaleArc;
}

void QwtDial::setOrigin( double origin )
{
    invalidateCache();

    d_data->origin = origin;
    sliderChange();
}

double QwtDial::origin() const
{
    return d_data->origin;
}

QSize QwtDial::sizeHint() const
{
    int sh = 0;
    if ( scaleDraw() )
        sh = qCeil( scaleDraw()->extent( font() ) );

    const int d = 6 * sh + 2 * lineWidth();

    QSize hint( d, d ); 
    if ( !isReadOnly() )
        hint = hint.expandedTo( QApplication::globalStrut() );

    return hint;
}

QSize QwtDial::minimumSizeHint() const
{
    int sh = 0;
    if ( scaleDraw() )
        sh = qCeil( scaleDraw()->extent( font() ) );

    const int d = 3 * sh + 2 * lineWidth();

    return QSize( d, d );
}

bool QwtDial::isScrollPosition( const QPoint &pos ) const
{
    const QRegion region( innerRect(), QRegion::Ellipse );
    if ( region.contains( pos ) && ( pos != innerRect().center() ) )
    {
        double angle = QLineF( rect().center(), pos ).angle();
        if ( d_data->mode == QwtDial::RotateScale )
            angle = 360.0 - angle;

        double valueAngle = 
            qwtNormalizeDegrees( 90.0 - scaleMap().transform( value() ) );

        d_data->mouseOffset = qwtNormalizeDegrees( angle - valueAngle );
        d_data->arcOffset = scaleMap().p1();

        return true;
    }

    return false;
}

double QwtDial::scrolledTo( const QPoint &pos ) const
{
    double angle = QLineF( rect().center(), pos ).angle();
    if ( d_data->mode == QwtDial::RotateScale )
    {
        angle += scaleMap().p1() - d_data->arcOffset;
        angle = 360.0 - angle;
    }

    angle = qwtNormalizeDegrees( angle - d_data->mouseOffset );
    angle = qwtNormalizeDegrees( 90.0 - angle );

    if ( scaleMap().pDist() >= 360.0 )
    {
        if ( angle < scaleMap().p1() )
            angle += 360.0;

        if ( !wrapping() )
        {
            double boundedAngle = angle;

            const double arc = angle - scaleMap().transform( value() );
            if ( qAbs( arc ) > 180.0 )
            {
                boundedAngle = ( arc > 0 ) 
                    ? scaleMap().p1() : scaleMap().p2();
            }

            d_data->mouseOffset += ( boundedAngle - angle );

            angle = boundedAngle;
        }
    }
    else
    {
        const double boundedAngle =
            qwtBoundedAngle( scaleMap().p1(), angle, scaleMap().p2() );

        if ( !wrapping() )
            d_data->mouseOffset += ( boundedAngle - angle );

        angle = boundedAngle;
    }

    return scaleMap().invTransform( angle );
}

void QwtDial::changeEvent( QEvent *event )
{
    switch( event->type() )
    {
        case QEvent::EnabledChange:
        case QEvent::FontChange:
        case QEvent::StyleChange:
        case QEvent::PaletteChange:
        case QEvent::LanguageChange:
        case QEvent::LocaleChange:
        {
            invalidateCache();
            break;
        }
        default:
            break;
    }
    
    QwtAbstractSlider::changeEvent( event );
}

void QwtDial::wheelEvent( QWheelEvent *event )
{
    const QRegion region( innerRect(), QRegion::Ellipse );
    if ( region.contains( event->pos() ) )
        QwtAbstractSlider::wheelEvent( event );
}

void QwtDial::setAngleRange( double angle, double span )
{
    QwtRoundScaleDraw *sd = const_cast<QwtRoundScaleDraw *>( scaleDraw() );
    if ( sd  )
    {
        angle = qwtNormalizeDegrees( angle - 270.0 );
        sd->setAngleRange( angle, angle + span );
    }
}

void QwtDial::scaleChange()
{
    invalidateCache();
    QwtAbstractSlider::scaleChange();
}

void QwtDial::sliderChange()
{
    setAngleRange( d_data->origin + d_data->minScaleArc,
        d_data->maxScaleArc - d_data->minScaleArc );

    if ( mode() == RotateScale )
    {
        const double arc = scaleMap().transform( value() ) - scaleMap().p1();
        setAngleRange( d_data->origin - arc,
            d_data->maxScaleArc - d_data->minScaleArc );
    }

    QwtAbstractSlider::sliderChange();
}