Public Types¶

enum Attribute { WithoutGaps = 0x01 }
Raster data attributes. enum ConrecFlag { IgnoreAllVerticesOnLevel = 0x01, IgnoreOutOfRange = 0x02 }
Flags to modify the contour algorithm. typedef QMap< double, QPolygonF > ContourLines
Contour lines. typedef QFlags< Attribute > Attributes
typedef QFlags< ConrecFlag > ConrecFlags

Public Member Functions¶

QwtRasterData ()
Constructor. virtual ~QwtRasterData ()
Destructor. void setAttribute (Attribute, bool on=true)
bool testAttribute (Attribute) const
virtual QwtInterval interval (Qt::Axis) const =0
virtual QRectF pixelHint (const QRectF &) const
Pixel hint. virtual void initRaster (const QRectF &, const QSize &raster)
Initialize a raster. virtual void discardRaster ()
Discard a raster. virtual double value (double x, double y) const =0
virtual ContourLines contourLines (const QRectF &rect, const QSize &raster, const QList< double > &levels, ConrecFlags) const

typedef QFlags<Attribute > QwtRasterData::Attributes¶

An ORed combination of Attribute values.

Definition at line 74 of file qwt_raster_data.h.

typedef QFlags<ConrecFlag > QwtRasterData::ConrecFlags¶

An ORed combination of ConrecFlag values.

Definition at line 86 of file qwt_raster_data.h.

enum QwtRasterData::Attribute¶

Raster data attributes. Additional information that is used to improve processing of the data.

Enumerator

WithoutGaps

The bounding rectangle of the data is spanned by the interval(Qt::XAxis) and interval(Qt::YAxis).

WithoutGaps indicates, that the data has no gaps ( unknown values ) in this area and the result of value() does not need to be checked for NaN values.

Enabling this flag will have an positive effect on the performance of rendering a QwtPlotSpectrogram.

The default setting is false.

Note

Definition at line 54 of file qwt_raster_data.h.

enum QwtRasterData::ConrecFlag¶

Flags to modify the contour algorithm.

Enumerator

IgnoreAllVerticesOnLevel

Ignore all vertices on the same level.

IgnoreOutOfRange

Ignore all values, that are out of range.

Definition at line 77 of file qwt_raster_data.h.

QwtRasterData::ContourLines QwtRasterData::contourLines (const QRectF & rect, const QSize & raster, const QList< double > & levels, ConrecFlags flags) const [virtual]¶

Calculate contour lines

Parameters

Returns

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

Definition at line 286 of file qwt_raster_data.cpp.

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

Definition at line 237 of file qwt_raster_data.cpp.

void QwtRasterData::initRaster (const QRectF & area, 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

See also

Definition at line 221 of file qwt_raster_data.cpp.

virtual QwtInterval QwtRasterData::interval (Qt::Axis) const [pure virtual]¶

Returns

See also

Implemented in QwtMatrixRasterData.

QRectF QwtRasterData::pixelHint (const QRectF & area) const [virtual]¶

Pixel hint. pixelHint() returns the geometry of a pixel, that can be used to calculate the resolution and alignment of the plot item, that is representing the data.

Width and height of the hint need to be the horizontal and vertical distances between 2 neighbored points. The center of the hint has to be the position of any point ( it doesn't matter which one ).

An empty hint indicates, that there are values for any detail level.

Limiting the resolution of the image might significantly improve the performance and heavily reduce the amount of memory when rendering a QImage from the raster data.

The default implementation returns an empty rectangle recommending to render in target device ( f.e. screen ) resolution.

Parameters

Returns

Reimplemented in QwtMatrixRasterData.

Definition at line 267 of file qwt_raster_data.cpp.

void QwtRasterData::setAttribute (Attribute attribute, bool on = true)¶

Specify an attribute of the data

Parameters

Definition at line 189 of file qwt_raster_data.cpp.

bool QwtRasterData::testAttribute (Attribute attribute) const¶

Returns

See also

Definition at line 201 of file qwt_raster_data.cpp.

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

Returns

Parameters

Implemented in QwtMatrixRasterData.