QwtRasterData defines an interface to any type of raster data. More...

#include <qwt_raster_data.h>

Inheritance diagram for QwtRasterData:

Collaboration diagram for QwtRasterData:

Classes
class	Contour3DPoint
class	ContourPlane
Public Types
enum	ConrecAttribute { IgnoreAllVerticesOnLevel = 1, IgnoreOutOfRange = 2 }
	Attribute to modify the contour algorithm. More...
typedef QMap< double, QMemArray< QwtDoublePoint > >	ContourLines
Public Member Functions
	QwtRasterData ()
	Constructor.
	QwtRasterData (const QwtDoubleRect &)
virtual	~QwtRasterData ()
	Destructor.
virtual QwtRasterData *	copy () const =0
	Clone the data.
virtual void	setBoundingRect (const QwtDoubleRect &)
QwtDoubleRect	boundingRect () const
virtual QSize	rasterHint (const QwtDoubleRect &) const
	Find the raster of the data for an area.
virtual void	initRaster (const QwtDoubleRect &, const QSize &raster)
	Initialize a raster.
virtual void	discardRaster ()
	Discard a raster.
virtual double	value (double x, double y) const =0
virtual QwtDoubleInterval	range () const =0
virtual ContourLines	contourLines (const QwtDoubleRect &rect, const QSize &raster, const QValueList< double > &levels, int flags) const

Detailed Description

QwtRasterData defines an interface to any type of raster data.

QwtRasterData is an abstract interface, that is used by QwtPlotRasterItem to find the values at the pixels of its raster.

Often a raster item is used to display values from a matrix. Then the derived raster data class needs to implement some sort of resampling, that maps the raster of the matrix into the requested raster of the raster item ( depending on resolution and scales of the canvas ).

Definition at line 61 of file qwt_raster_data.h.

Member Typedef Documentation

typedef QMap<double, QMemArray <QwtDoublePoint> > QwtRasterData::ContourLines

Definition at line 67 of file qwt_raster_data.h.

Member Enumeration Documentation

enum QwtRasterData::ConrecAttribute

Attribute to modify the contour algorithm.

Enumerator:

IgnoreAllVerticesOnLevel
IgnoreOutOfRange

Definition at line 71 of file qwt_raster_data.h.

    {
        IgnoreAllVerticesOnLevel = 1,
        IgnoreOutOfRange = 2
    };

Constructor & Destructor Documentation

QwtRasterData::QwtRasterData ( )

Constructor.

Definition at line 185 of file qwt_raster_data.cpp.

{
}

QwtRasterData::QwtRasterData ( const QwtDoubleRect & boundingRect )

Constructor

Parameters:

boundingRect Bounding rectangle

See also:: setBoundingRect()

Definition at line 195 of file qwt_raster_data.cpp.

                                                             :
    d_boundingRect(boundingRect)
{
}

QwtRasterData::~QwtRasterData ( ) [virtual]

Destructor.

Definition at line 201 of file qwt_raster_data.cpp.

{
}

Member Function Documentation

QwtDoubleRect QwtRasterData::boundingRect ( ) const

Returns:: Bounding rectangle

See also:: boundingRect()

Definition at line 220 of file qwt_raster_data.cpp.

Referenced by QwtPlotSpectrogram::boundingRect(), and setBoundingRect().

{
    return d_boundingRect;
}

QwtRasterData::ContourLines QwtRasterData::contourLines	(	const QwtDoubleRect &	rect,
		const QSize &	raster,
		const QValueList< double > &	levels,
		int	flags
	)		const `[virtual]`

Calculate contour lines

An adaption of CONREC, a simple contouring algorithm. http://local.wasp.uwa.edu.au/~pbourke/papers/conrec/

Definition at line 292 of file qwt_raster_data.cpp.

References QwtDoubleInterval::contains(), IgnoreAllVerticesOnLevel, int(), QwtRasterData::ContourPlane::intersect(), QwtDoubleInterval::isValid(), QwtRasterData::Contour3DPoint::setPos(), QwtRasterData::Contour3DPoint::setZ(), and QwtRasterData::Contour3DPoint::z().

Referenced by QwtPlotSpectrogram::renderContourLines().

{   
    ContourLines contourLines;
    
    if ( levels.size() == 0 || !rect.isValid() || !raster.isValid() )
        return contourLines;

    const double dx = rect.width() / raster.width();
    const double dy = rect.height() / raster.height();

    const bool ignoreOnPlane =
        flags & QwtRasterData::IgnoreAllVerticesOnLevel;

    const QwtDoubleInterval range = this->range();
    bool ignoreOutOfRange = false;
    if ( range.isValid() )
        ignoreOutOfRange = flags & IgnoreOutOfRange;

    ((QwtRasterData*)this)->initRaster(rect, raster);

    for ( int y = 0; y < raster.height() - 1; y++ )
    {
        enum Position
        {
            Center,

            TopLeft,
            TopRight,
            BottomRight,
            BottomLeft,

            NumPositions
        };

        Contour3DPoint xy[NumPositions];

        for ( int x = 0; x < raster.width() - 1; x++ )
        {
            const QwtDoublePoint pos(rect.x() + x * dx, rect.y() + y * dy);

            if ( x == 0 )
            {
                xy[TopRight].setPos(pos.x(), pos.y());
                xy[TopRight].setZ(
                    value( xy[TopRight].x(), xy[TopRight].y())
                );

                xy[BottomRight].setPos(pos.x(), pos.y() + dy);
                xy[BottomRight].setZ(
                    value(xy[BottomRight].x(), xy[BottomRight].y())
                );
            }

            xy[TopLeft] = xy[TopRight];
            xy[BottomLeft] = xy[BottomRight];

            xy[TopRight].setPos(pos.x() + dx, pos.y());
            xy[BottomRight].setPos(pos.x() + dx, pos.y() + dy);

            xy[TopRight].setZ(
                value(xy[TopRight].x(), xy[TopRight].y())
            );
            xy[BottomRight].setZ(
                value(xy[BottomRight].x(), xy[BottomRight].y())
            );

            double zMin = xy[TopLeft].z();
            double zMax = zMin;
            double zSum = zMin;

            for ( int i = TopRight; i <= BottomLeft; i++ )
            {
                const double z = xy[i].z();

                zSum += z;
                if ( z < zMin )
                    zMin = z;
                if ( z > zMax )
                    zMax = z;
            }

            if ( ignoreOutOfRange )
            {
                if ( !range.contains(zMin) || !range.contains(zMax) )
                    continue;
            }

            if ( zMax < levels[0] ||
                zMin > levels[levels.size() - 1] )
            {
                continue;
            }

            xy[Center].setPos(pos.x() + 0.5 * dx, pos.y() + 0.5 * dy);
            xy[Center].setZ(0.25 * zSum);
            const int numLevels = (int)levels.size();
            for (int l = 0; l < numLevels; l++)
            {
                const double level = levels[l];
                if ( level < zMin || level > zMax )
                    continue;
#if QT_VERSION >= 0x040000
                QPolygonF &lines = contourLines[level];
#else
                QwtArray<QwtDoublePoint> &lines = contourLines[level];
#endif
                const ContourPlane plane(level);

                QwtDoublePoint line[2];
                Contour3DPoint vertex[3];

                for (int m = TopLeft; m < NumPositions; m++)
                {
                    vertex[0] = xy[m];
                    vertex[1] = xy[0];
                    vertex[2] = xy[m != BottomLeft ? m + 1 : TopLeft];

                    const bool intersects =
                        plane.intersect(vertex, line, ignoreOnPlane);
                    if ( intersects )
                    {
#if QT_VERSION >= 0x040000
                        lines += line[0];
                        lines += line[1];
#else
                        const int index = lines.size();
                        lines.resize(lines.size() + 2, QGArray::SpeedOptim);

                        lines[index] = line[0];
                        lines[index+1] = line[1];
#endif
                    }
                }
            }
        }
    }

    ((QwtRasterData*)this)->discardRaster();

    return contourLines;
}

virtual QwtRasterData* QwtRasterData::copy ( ) const [pure virtual]

Clone the data.

Implemented in QwtPlotSpectrogram::PrivateData::DummyData.

Referenced by QwtPlotSpectrogram::setData().

void QwtRasterData::discardRaster ( ) [virtual]

Discard a raster.

After the composition of an image QwtPlotSpectrogram calls discardRaster().

The default implementation does nothing, but if data has been loaded in initRaster(), it could deleted now.

See also:: initRaster(), value()

Definition at line 254 of file qwt_raster_data.cpp.

Referenced by QwtPlotSpectrogram::renderImage().

{
}

void QwtRasterData::initRaster	(	const QwtDoubleRect &	,
		const QSize &	raster
	)		`[virtual]`

Initialize a raster.

Before the composition of an image QwtPlotSpectrogram calls initRaster, announcing the area and its resolution that will be requested.

The default implementation does nothing, but for data sets that are stored in files, it might be good idea to reimplement initRaster, where the data is resampled and loaded into memory.

Parameters:

rect	Area of the raster
raster	Number of horizontal and vertical pixels

See also:: initRaster(), value()

Definition at line 240 of file qwt_raster_data.cpp.

Referenced by QwtPlotSpectrogram::renderImage().

{
}

virtual QwtDoubleInterval QwtRasterData::range ( ) const [pure virtual]

Returns:: the range of the values

Implemented in QwtPlotSpectrogram::PrivateData::DummyData.

Referenced by QwtPlotSpectrogram::contourPen(), QwtPlotSpectrogram::drawContourLines(), and QwtPlotSpectrogram::renderImage().

QSize QwtRasterData::rasterHint ( const QwtDoubleRect & ) const [virtual]

Find the raster of the data for an area.

The resolution is the number of horizontal and vertical pixels that the data can return for an area. An invalid resolution indicates that the data can return values for any detail level.

The resolution will limit the size of the image that is rendered from the data. F.e. this might be important when printing a spectrogram to a A0 printer with 600 dpi.

The default implementation returns an invalid resolution (size)

Parameters:

rect	In most implementations the resolution of the data doesn't depend on the requested rectangle.

Returns:: Resolution, as number of horizontal and vertical pixels

Definition at line 276 of file qwt_raster_data.cpp.

Referenced by QwtPlotSpectrogram::contourRasterSize(), QwtPlotSpectrogram::rasterHint(), and QwtPlotSpectrogram::renderImage().

{
    return QSize(); // use screen resolution
}

void QwtRasterData::setBoundingRect ( const QwtDoubleRect & boundingRect ) [virtual]

Set the bounding rect ( == area, un plot coordinates )

Parameters:

boundingRect Bounding rectangle

See also:: boundingRect()

Definition at line 211 of file qwt_raster_data.cpp.

References boundingRect().

{
    d_boundingRect = boundingRect;
}

virtual double QwtRasterData::value	(	double	x,
		double	y
	)		const `[pure virtual]`

Returns:: the value at a raster position

Parameters:

x	X value in plot coordinates
y	Y value in plot coordinates

Implemented in QwtPlotSpectrogram::PrivateData::DummyData.

Referenced by QwtPlotSpectrogram::renderImage().

The documentation for this class was generated from the following files:

QwtRasterData Class Reference

Classes

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation