qwt_polar_spectrogram.cpp

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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * QwtPolar Widget Library
 * Copyright (C) 2008   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_polar_spectrogram.h"
#include "qwt_polar.h"
#include "qwt_polar_plot.h"
#include "qwt_color_map.h"
#include "qwt_scale_map.h"
#include "qwt_raster_data.h"
#include "qwt_math.h"
#include "qwt_clipper.h"

#include <qpainter.h>
#include <qpainterpath.h>
#include <qnumeric.h>
#include <qthread.h>
#include <qfuture.h>
#include <qtconcurrentrun.h>

class QwtPolarSpectrogram::TileInfo
{
public:
    QPoint imagePos;
    QRect rect;
    QImage *image;
};

class QwtPolarSpectrogram::PrivateData
{
public:
    PrivateData():
        data( NULL )
    {
        colorMap = new QwtLinearColorMap();
    }

    ~PrivateData()
    {
        delete data;
        delete colorMap;
    }

    QwtRasterData *data;
    QwtColorMap *colorMap;

    QwtPolarSpectrogram::PaintAttributes paintAttributes;
};

QwtPolarSpectrogram::QwtPolarSpectrogram():
    QwtPolarItem( QwtText( "Spectrogram" ) )
{
    d_data = new PrivateData;

    setItemAttribute( QwtPolarItem::AutoScale );
    setItemAttribute( QwtPolarItem::Legend, false );

    setZ( 20.0 );
}

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

int QwtPolarSpectrogram::rtti() const
{
    return QwtPolarItem::Rtti_PolarSpectrogram;
}

void QwtPolarSpectrogram::setData( QwtRasterData *data )
{
    if ( data != d_data->data )
    {
        delete d_data->data;
        d_data->data = data;

        itemChanged();
    }
}

const QwtRasterData *QwtPolarSpectrogram::data() const
{
    return d_data->data;
}

void QwtPolarSpectrogram::setColorMap( QwtColorMap *colorMap )
{
    if ( d_data->colorMap != colorMap )
    {
        delete d_data->colorMap;
        d_data->colorMap = colorMap;
    }

    itemChanged();
}

const QwtColorMap *QwtPolarSpectrogram::colorMap() const
{
    return d_data->colorMap;
}

void QwtPolarSpectrogram::setPaintAttribute( PaintAttribute attribute, bool on )
{
    if ( on )
        d_data->paintAttributes |= attribute;
    else
        d_data->paintAttributes &= ~attribute;
}

bool QwtPolarSpectrogram::testPaintAttribute( PaintAttribute attribute ) const
{
    return ( d_data->paintAttributes & attribute );
}

void QwtPolarSpectrogram::draw( QPainter *painter,
    const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap,
    const QPointF &pole, double,
    const QRectF &canvasRect ) const
{
    const QRectF plotRect = plot()->plotRect( canvasRect.toRect() );
    QRect imageRect = canvasRect.toRect();

    painter->save();

    painter->setClipRect( canvasRect );
    
    QPainterPath clipPathCanvas;
    clipPathCanvas.addEllipse( plotRect );
    painter->setClipPath( clipPathCanvas, Qt::IntersectClip );

    imageRect &= plotRect.toAlignedRect(); // outer rect

    const QwtInterval radialInterval = boundingInterval( QwtPolar::ScaleRadius );
    if ( radialInterval.isValid() )
    {
        const double radius = radialMap.transform( radialInterval.maxValue() ) -
            radialMap.transform( radialInterval.minValue() );

        QRectF clipRect( 0, 0, 2 * radius, 2 * radius );
        clipRect.moveCenter( pole );

        imageRect &= clipRect.toRect(); // inner rect, we don't have points outside

        QPainterPath clipPathRadial;
        clipPathRadial.addEllipse( clipRect );
        painter->setClipPath( clipPathRadial, Qt::IntersectClip );
    }

    const QImage image = renderImage( azimuthMap, radialMap, pole, imageRect );
    painter->drawImage( imageRect, image );

    painter->restore();
}

QImage QwtPolarSpectrogram::renderImage(
    const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap,
    const QPointF &pole, const QRect &rect ) const
{
    if ( d_data->data == NULL || d_data->colorMap == NULL )
        return QImage();

    QImage image( rect.size(), d_data->colorMap->format() == QwtColorMap::RGB
                  ? QImage::Format_ARGB32 : QImage::Format_Indexed8 );

    const QwtInterval intensityRange = d_data->data->interval( Qt::ZAxis );
    if ( !intensityRange.isValid() )
        return image;

    if ( d_data->colorMap->format() == QwtColorMap::Indexed )
        image.setColorTable( d_data->colorMap->colorTable256() );

    /*
     For the moment we only announce the composition of the image by
     calling initRaster(), but we don't pass any useful parameters.
     ( How to map rect into something, that is useful to initialize a matrix
       of values in polar coordinates ? )
     */
    d_data->data->initRaster( QRectF(), QSize() );


#if !defined(QT_NO_QFUTURE)
    uint numThreads = renderThreadCount();

    if ( numThreads <= 0 )
        numThreads = QThread::idealThreadCount();

    if ( numThreads <= 0 )
        numThreads = 1;

    const int numRows = rect.height() / numThreads;


    QVector<TileInfo> tileInfos;
    for ( uint i = 0; i < numThreads; i++ )
    {
        QRect tile( rect.x(), rect.y() + i * numRows, rect.width(), numRows );
        if ( i == numThreads - 1 )
            tile.setHeight( rect.height() - i * numRows );

        TileInfo tileInfo;
        tileInfo.imagePos = rect.topLeft();
        tileInfo.rect = tile;
        tileInfo.image = &image;

        tileInfos += tileInfo;
    }

    QVector< QFuture<void> > futures;
    for ( int i = 0; i < tileInfos.size(); i++ )
    {
        if ( i == tileInfos.size() - 1 )
        {
            renderTile( azimuthMap, radialMap, pole, &tileInfos[i] );
        }
        else
        {
            futures += QtConcurrent::run( this, &QwtPolarSpectrogram::renderTile,
                azimuthMap, radialMap, pole, &tileInfos[i] );
        }
    }
    for ( int i = 0; i < futures.size(); i++ )
        futures[i].waitForFinished();

#else
    renderTile( azimuthMap, radialMap, pole, rect.topLeft(), rect, &image );
#endif

    d_data->data->discardRaster();

    return image;
}

void QwtPolarSpectrogram::renderTile(
    const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap,
    const QPointF &pole, TileInfo *tileInfo ) const
{
    renderTile( azimuthMap, radialMap, pole,
        tileInfo->imagePos, tileInfo->rect, tileInfo->image );
}

void QwtPolarSpectrogram::renderTile(
    const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap,
    const QPointF &pole, const QPoint &imagePos,
    const QRect &tile, QImage *image ) const
{
    const QwtInterval intensityRange = d_data->data->interval( Qt::ZAxis );
    if ( !intensityRange.isValid() )
        return;

    const bool doFastAtan = testPaintAttribute( ApproximatedAtan );

    const int y0 = imagePos.y();
    const int y1 = tile.top();
    const int y2 = tile.bottom();

    const int x0 = imagePos.x();
    const int x1 = tile.left();
    const int x2 = tile.right();

    if ( d_data->colorMap->format() == QwtColorMap::RGB )
    {
        for ( int y = y1; y <= y2; y++ )
        {
            const double dy = pole.y() - y;
            const double dy2 = qwtSqr( dy );

            QRgb *line = reinterpret_cast<QRgb *>( image->scanLine( y - y0 ) );
            line += x1 - x0;

            for ( int x = x1; x <= x2; x++ )
            {
                const double dx = x - pole.x();

                double a =  doFastAtan ? qwtFastAtan2( dy, dx ) : qAtan2( dy, dx );

                if ( a < 0.0 )
                    a += 2 * M_PI;

                if ( a < azimuthMap.p1() )
                    a += 2 * M_PI;

                const double r = qSqrt( qwtSqr( dx ) + dy2 );

                const double azimuth = azimuthMap.invTransform( a );
                const double radius = radialMap.invTransform( r );

                const double value = d_data->data->value( azimuth, radius );
                if ( qIsNaN( value ) )
                {
                    *line++ = 0u;
                }
                else
                {
                    *line++ = d_data->colorMap->rgb( intensityRange, value );
                }
            }
        }
    }
    else if ( d_data->colorMap->format() == QwtColorMap::Indexed )
    {
        for ( int y = y1; y <= y2; y++ )
        {
            const double dy = pole.y() - y;
            const double dy2 = qwtSqr( dy );

            unsigned char *line = image->scanLine( y - y0 );
            line += x1 - x0;
            for ( int x = x1; x <= x2; x++ )
            {
                const double dx = x - pole.x();

                double a =  doFastAtan ? qwtFastAtan2( dy, dx ) : qAtan2( dy, dx );
                if ( a < 0.0 )
                    a += 2 * M_PI;
                if ( a < azimuthMap.p1() )
                    a += 2 * M_PI;

                const double r = qSqrt( qwtSqr( dx ) + dy2 );

                const double azimuth = azimuthMap.invTransform( a );
                const double radius = radialMap.invTransform( r );

                const double value = d_data->data->value( azimuth, radius );

                const uint index = d_data->colorMap->colorIndex( 256, intensityRange, value );
                *line++ = static_cast<unsigned char>( index );
            }
        }
    }
}

QwtInterval QwtPolarSpectrogram::boundingInterval( int scaleId ) const
{
    if ( scaleId == QwtPolar::ScaleRadius )
        return d_data->data->interval( Qt::YAxis );

    return QwtPolarItem::boundingInterval( scaleId );
}