double QwtPlotRescaler::pixelDist( int axis, const QSize &size ) const
{
const QwtInterval intv = intervalHint( axis );
double dist = 0.0;
if ( !intv.isNull() )
{
if ( axis == referenceAxis() )
dist = intv.width();
else
{
const double r = aspectRatio( axis );
if ( r > 0.0 )
dist = intv.width() * r;
}
}
if ( dist > 0.0 )
{
if ( orientation( axis ) == Qt::Horizontal )
dist /= size.width();
else
dist /= size.height();
}
return dist;
}
/*!
Synchronize an axis scale according to the scale of the reference axis
\param axis Axis index ( see QwtPlot::AxisId )
\param reference Interval of the reference axis
\param size Size of the canvas
\return New interval for axis
*/
QwtInterval QwtPlotRescaler::syncScale( int axis,
const QwtInterval& reference, const QSize &size ) const
{
double dist;
if ( orientation( referenceAxis() ) == Qt::Horizontal )
dist = reference.width() / size.width();
else
dist = reference.width() / size.height();
if ( orientation( axis ) == Qt::Horizontal )
dist *= size.width();
else
dist *= size.height();
dist /= aspectRatio( axis );
QwtInterval intv;
if ( rescalePolicy() == Fitting )
intv = intervalHint( axis );
else
intv = interval( axis );
intv = expandInterval( intv, dist, expandingDirection( axis ) );
return intv;
}
/*!
Calculate the new scale interval of a plot axis
\param axis Axis index ( see QwtPlot::AxisId )
\param oldSize Previous size of the canvas
\param newSize New size of the canvas
\return Calculated new interval for the axis
*/
QwtInterval QwtPlotRescaler::expandScale( int axis,
const QSize &oldSize, const QSize &newSize ) const
{
const QwtInterval oldInterval = interval( axis );
QwtInterval expanded = oldInterval;
switch ( rescalePolicy() )
{
case Fixed:
{
break; // do nothing
}
case Expanding:
{
if ( !oldSize.isEmpty() )
{
double width = oldInterval.width();
if ( orientation( axis ) == Qt::Horizontal )
width *= double( newSize.width() ) / oldSize.width();
else
width *= double( newSize.height() ) / oldSize.height();
expanded = expandInterval( oldInterval,
width, expandingDirection( axis ) );
}
break;
}
case Fitting:
{
double dist = 0.0;
for ( int ax = 0; ax < QwtPlot::axisCnt; ax++ )
{
const double d = pixelDist( ax, newSize );
if ( d > dist )
dist = d;
}
if ( dist > 0.0 )
{
double width;
if ( orientation( axis ) == Qt::Horizontal )
width = newSize.width() * dist;
else
width = newSize.height() * dist;
expanded = expandInterval( intervalHint( axis ),
width, expandingDirection( axis ) );
}
break;
}
}
return expanded;
}
//! Adjust the plot axes scales
void QwtPlotRescaler::rescale() const
{
#if 0
const int axis = referenceAxis();
if ( axis < 0 || axis >= QwtPlot::axisCnt )
return;
const QwtDoubleInterval hint = intervalHint(axis);
if ( !hint.isNull() )
{
QwtPlot *plt = (QwtPlot *)plot();
const bool doReplot = plt->autoReplot();
plt->setAutoReplot(false);
plt->setAxisScale(axis, hint.minValue(), hint.maxValue());
plt->setAutoReplot(doReplot);
plt->updateAxes();
}
#endif
const QSize size = canvas()->contentsRect().size();
rescale(size, size);
}