qwt/examples/sinusplot/main.cpp

/*****************************************************************************
 * Qwt Examples - Copyright (C) 2002 Uwe Rathmann
 * This file may be used under the terms of the 3-clause BSD License
 *****************************************************************************/

#include <QwtPlot>
#include <QwtPlotMarker>
#include <QwtPlotCurve>
#include <QwtLegend>
#include <QwtSyntheticPointData>
#include <QwtPlotCanvas>
#include <QwtPlotPanner>
#include <QwtPlotMagnifier>
#include <QwtSymbol>
#include <QwtText>
#include <QwtMath>

#include <QApplication>
#include <QPainterPath>
#include <QLayout>

//-----------------------------------------------------------------
//      A simple example which shows how to use QwtPlot connected
//      to a data class without any storage, calculating each values
//      on the fly.
//-----------------------------------------------------------------

namespace
{
    class FunctionData : public QwtSyntheticPointData
    {
      public:
        FunctionData( double( *fy )( double ) )
            : QwtSyntheticPointData( 100 ),
            m_y( fy )
        {
        }

        virtual double y( double x ) const QWT_OVERRIDE
        {
            return m_y( x );
        }

      private:
        double ( * m_y )( double );
    };

    class ArrowSymbol : public QwtSymbol
    {
      public:
        ArrowSymbol()
        {
            QPen pen( Qt::black, 0 );
            pen.setJoinStyle( Qt::MiterJoin );

            setPen( pen );
            setBrush( Qt::red );

            QPainterPath path;
            path.moveTo( 0, 8 );
            path.lineTo( 0, 5 );
            path.lineTo( -3, 5 );
            path.lineTo( 0, 0 );
            path.lineTo( 3, 5 );
            path.lineTo( 0, 5 );

            QTransform transform;
            transform.rotate( -30.0 );
            path = transform.map( path );

            setPath( path );
            setPinPoint( QPointF( 0, 0 ) );

            setSize( 10, 14 );
        }
    };

    class Plot : public QwtPlot
    {
      public:
        Plot( QWidget* parent = NULL );

      protected:
        virtual void resizeEvent( QResizeEvent* ) QWT_OVERRIDE;

      private:
        void populate();
        void updateGradient();
    };
}

Plot::Plot( QWidget* parent )
    : QwtPlot( parent )
{
    setAutoFillBackground( true );
    setPalette( QPalette( QColor( 165, 193, 228 ) ) );
    updateGradient();

    setTitle( "A Simple QwtPlot Demonstration" );
    insertLegend( new QwtLegend(), QwtPlot::RightLegend );

    // axes
    setAxisTitle( QwtAxis::XBottom, "x -->" );
    setAxisScale( QwtAxis::XBottom, 0.0, 10.0 );

    setAxisTitle( QwtAxis::YLeft, "y -->" );
    setAxisScale( QwtAxis::YLeft, -1.0, 1.0 );

    // canvas
    QwtPlotCanvas* canvas = new QwtPlotCanvas();
    canvas->setLineWidth( 1 );
    canvas->setFrameStyle( QFrame::Box | QFrame::Plain );
    canvas->setBorderRadius( 15 );

    QPalette canvasPalette( Qt::white );
    canvasPalette.setColor( QPalette::WindowText, QColor( 133, 190, 232 ) );
    canvas->setPalette( canvasPalette );

    setCanvas( canvas );

    // panning with the left mouse button
    ( void ) new QwtPlotPanner( canvas );

    // zoom in/out with the wheel
    ( void ) new QwtPlotMagnifier( canvas );

    populate();
}

void Plot::populate()
{
    // Insert new curves
    QwtPlotCurve* cSin = new QwtPlotCurve( "y = sin(x)" );
    cSin->setRenderHint( QwtPlotItem::RenderAntialiased );
    cSin->setLegendAttribute( QwtPlotCurve::LegendShowLine, true );
    cSin->setPen( Qt::red );
    cSin->attach( this );

    QwtPlotCurve* cCos = new QwtPlotCurve( "y = cos(x)" );
    cCos->setRenderHint( QwtPlotItem::RenderAntialiased );
    cCos->setLegendAttribute( QwtPlotCurve::LegendShowLine, true );
    cCos->setPen( Qt::blue );
    cCos->attach( this );

    // Create sin and cos data
    cSin->setData( new FunctionData( std::sin ) );
    cCos->setData( new FunctionData( std::cos ) );

    // Insert markers

    //  ...a horizontal line at y = 0...
    QwtPlotMarker* mY = new QwtPlotMarker();
    mY->setLabel( QString::fromLatin1( "y = 0" ) );
    mY->setLabelAlignment( Qt::AlignRight | Qt::AlignTop );
    mY->setLineStyle( QwtPlotMarker::HLine );
    mY->setYValue( 0.0 );
    mY->attach( this );

    //  ...a vertical line at x = 2 * pi
    QwtPlotMarker* mX = new QwtPlotMarker();
    mX->setLabel( QString::fromLatin1( "x = 2 pi" ) );
    mX->setLabelAlignment( Qt::AlignLeft | Qt::AlignBottom );
    mX->setLabelOrientation( Qt::Vertical );
    mX->setLineStyle( QwtPlotMarker::VLine );
    mX->setLinePen( Qt::black, 0, Qt::DashDotLine );
    mX->setXValue( 2.0 * M_PI );
    mX->attach( this );

    const double x = 7.7;

    // an arrow at a specific position
    QwtPlotMarker* mPos = new QwtPlotMarker( "Marker" );
    mPos->setRenderHint( QwtPlotItem::RenderAntialiased, true );
    mPos->setItemAttribute( QwtPlotItem::Legend, true );
    mPos->setSymbol( new ArrowSymbol() );
    mPos->setValue( QPointF( x, std::sin( x ) ) );
    mPos->setLabel( QString( "x = %1" ).arg( x ) );
    mPos->setLabelAlignment( Qt::AlignRight | Qt::AlignBottom );
    mPos->attach( this );
}

void Plot::updateGradient()
{
    QPalette pal = palette();

    const QColor buttonColor = pal.color( QPalette::Button );

    QLinearGradient gradient( rect().topLeft(), rect().bottomLeft() );
    gradient.setColorAt( 0.0, Qt::white );
    gradient.setColorAt( 0.7, buttonColor );
    gradient.setColorAt( 1.0, buttonColor );

    pal.setBrush( QPalette::Window, gradient );
    setPalette( pal );
}

void Plot::resizeEvent( QResizeEvent* event )
{
    QwtPlot::resizeEvent( event );

    // Qt 4.7.1: QGradient::StretchToDeviceMode is buggy on X11
    updateGradient();
}

int main( int argc, char* argv[] )
{
    QApplication app( argc, argv );

    Plot* plot = new Plot();

    // We put a dummy widget around to have
    // so that Qt paints a widget background
    // when resizing

    QWidget window;

    QHBoxLayout* layout = new QHBoxLayout( &window );
    layout->setContentsMargins( 0, 0, 0, 0 );
    layout->addWidget( plot );

    window.resize( 600, 400 );
    window.show();

    return app.exec();
}