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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_matrix_raster_data.h"
#include <qnumeric.h>
#include <qmath.h>
class QwtMatrixRasterData::PrivateData
{
public:
PrivateData():
resampleMode(QwtMatrixRasterData::NearestNeighbour),
numColumns(0)
{
}
inline double value(int row, int col) const
{
return values.data()[ row * numColumns + col ];
}
QwtMatrixRasterData::ResampleMode resampleMode;
QVector<double> values;
int numColumns;
int numRows;
double dx;
double dy;
};
//! Constructor
QwtMatrixRasterData::QwtMatrixRasterData()
{
d_data = new PrivateData();
update();
}
//! Destructor
QwtMatrixRasterData::~QwtMatrixRasterData()
{
delete d_data;
}
/*!
\brief Set the resampling algorithm
\param mode Resampling mode
\sa resampleMode(), value()
*/
void QwtMatrixRasterData::setResampleMode( ResampleMode mode )
{
d_data->resampleMode = mode;
}
/*!
\return resampling algorithm
\sa setResampleMode(), value()
*/
QwtMatrixRasterData::ResampleMode QwtMatrixRasterData::resampleMode() const
{
return d_data->resampleMode;
}
/*!
\brief Assign the bounding interval for an axis
Setting the bounding intervals for the X/Y axis is mandatory
to define the positions for the values of the value matrix.
The interval in Z direction defines the possible range for
the values in the matrix, what is f.e used by QwtPlotSpectrogram
to map values to colors. The Z-interval might be the bounding
interval of the values in the matrix, but usually it isn't.
( f.e a interval of 0.0-100.0 for values in percentage )
\param axis X, Y or Z axis
\param interval Interval
\sa QwtRasterData::interval(), setValueMatrix()
*/
void QwtMatrixRasterData::setInterval(
Qt::Axis axis, const QwtInterval &interval )
{
QwtRasterData::setInterval( axis, interval );
update();
}
/*!
\brief Assign a value matrix
The positions of the values are calculated by dividing
the bounding rectangle of the X/Y intervals into equidistant
rectangles ( pixels ). Each value corresponds to the center of
a pixel.
\param values Vector of values
\param numColumns Number of columns
\sa valueMatrix(), numColumns(), numRows(), setInterval()()
*/
void QwtMatrixRasterData::setValueMatrix(
const QVector<double> &values, int numColumns )
{
d_data->values = values;
d_data->numColumns = qMax( numColumns, 0 );
update();
}
/*!
\return Value matrix
\sa setValueMatrix(), numColumns(), numRows(), setInterval()
*/
const QVector<double> QwtMatrixRasterData::valueMatrix() const
{
return d_data->values;
}
/*!
\brief Change a single value in the matrix
\param row Row index
\param col Column index
\param value New value
\sa value(), setValueMatrix()
*/
void QwtMatrixRasterData::setValue( int row, int col, double value )
{
if ( row >= 0 && row < d_data->numRows &&
col >= 0 && col < d_data->numColumns )
{
const int index = row * d_data->numColumns + col;
d_data->values.data()[ index ] = value;
}
}
/*!
\return Number of columns of the value matrix
\sa valueMatrix(), numRows(), setValueMatrix()
*/
int QwtMatrixRasterData::numColumns() const
{
return d_data->numColumns;
}
/*!
\return Number of rows of the value matrix
\sa valueMatrix(), numColumns(), setValueMatrix()
*/
int QwtMatrixRasterData::numRows() const
{
return d_data->numRows;
}
/*!
\brief Calculate the 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.
- NearestNeighbour\n
pixelHint() returns the surrounding pixel of the top left value
in the matrix.
- BilinearInterpolation\n
Returns an empty rectangle recommending
to render in target device ( f.e. screen ) resolution.
\param area Requested area, ignored
\return Calculated hint
\sa ResampleMode, setMatrix(), setInterval()
*/
QRectF QwtMatrixRasterData::pixelHint( const QRectF &area ) const
{
Q_UNUSED( area )
QRectF rect;
if ( d_data->resampleMode == NearestNeighbour )
{
const QwtInterval intervalX = interval( Qt::XAxis );
const QwtInterval intervalY = interval( Qt::YAxis );
if ( intervalX.isValid() && intervalY.isValid() )
{
rect = QRectF( intervalX.minValue(), intervalY.minValue(),
d_data->dx, d_data->dy );
}
}
return rect;
}
/*!
\return the value at a raster position
\param x X value in plot coordinates
\param y Y value in plot coordinates
\sa ResampleMode
*/
double QwtMatrixRasterData::value( double x, double y ) const
{
const QwtInterval xInterval = interval( Qt::XAxis );
const QwtInterval yInterval = interval( Qt::YAxis );
if ( !( xInterval.contains(x) && yInterval.contains(y) ) )
return qQNaN();
double value;
switch( d_data->resampleMode )
{
case BilinearInterpolation:
{
int col1 = qRound( (x - xInterval.minValue() ) / d_data->dx ) - 1;
int row1 = qRound( (y - yInterval.minValue() ) / d_data->dy ) - 1;
int col2 = col1 + 1;
int row2 = row1 + 1;
if ( col1 < 0 )
col1 = col2;
else if ( col2 >= static_cast<int>( d_data->numColumns ) )
col2 = col1;
if ( row1 < 0 )
row1 = row2;
else if ( row2 >= static_cast<int>( d_data->numRows ) )
row2 = row1;
const double v11 = d_data->value( row1, col1 );
const double v21 = d_data->value( row1, col2 );
const double v12 = d_data->value( row2, col1 );
const double v22 = d_data->value( row2, col2 );
const double x2 = xInterval.minValue() +
( col2 + 0.5 ) * d_data->dx;
const double y2 = yInterval.minValue() +
( row2 + 0.5 ) * d_data->dy;
const double rx = ( x2 - x ) / d_data->dx;
const double ry = ( y2 - y ) / d_data->dy;
const double vr1 = rx * v11 + ( 1.0 - rx ) * v21;
const double vr2 = rx * v12 + ( 1.0 - rx ) * v22;
value = ry * vr1 + ( 1.0 - ry ) * vr2;
break;
}
case NearestNeighbour:
default:
{
int row = int( (y - yInterval.minValue() ) / d_data->dy );
int col = int( (x - xInterval.minValue() ) / d_data->dx );
// In case of intervals, where the maximum is included
// we get out of bound for row/col, when the value for the
// maximum is requested. Instead we return the value
// from the last row/col
if ( row >= d_data->numRows )
row = d_data->numRows - 1;
if ( col >= d_data->numColumns )
col = d_data->numColumns - 1;
value = d_data->value( row, col );
}
}
return value;
}
void QwtMatrixRasterData::update()
{
d_data->numRows = 0;
d_data->dx = 0.0;
d_data->dy = 0.0;
if ( d_data->numColumns > 0 )
{
d_data->numRows = d_data->values.size() / d_data->numColumns;
const QwtInterval xInterval = interval( Qt::XAxis );
const QwtInterval yInterval = interval( Qt::YAxis );
if ( xInterval.isValid() )
d_data->dx = xInterval.width() / d_data->numColumns;
if ( yInterval.isValid() )
d_data->dy = yInterval.width() / d_data->numRows;
}
}