/*!
Build a scale map
The azimuth map translates between the scale values and angles from
[0.0, 2 * PI[. The radial map translates scale values into the distance
from the pole.
\param scaleId Scale index
\param radius Radius of the plot are in pixels
\return Map for the scale on the canvas. With this map pixel coordinates can
translated to plot coordinates and vice versa.
\sa QwtScaleMap, transform(), invTransform()
*/
QwtScaleMap QwtPolarPlot::scaleMap( int scaleId, const double radius ) const
{
if ( scaleId < 0 || scaleId >= QwtPolar::ScaleCount )
return QwtScaleMap();
QwtScaleMap map;
map.setTransformation( scaleEngine( scaleId )->transformation() );
const QwtScaleDiv *sd = scaleDiv( scaleId );
#if QWT_VERSION < 0x050200
map.setScaleInterval( sd->lBound(), sd->hBound() );
#else
map.setScaleInterval( sd->lowerBound(), sd->upperBound() );
#endif
if ( scaleId == QwtPolar::Azimuth )
{
map.setPaintXInterval( d_data->azimuthOrigin,
d_data->azimuthOrigin + M_2PI );
}
else
{
map.setPaintXInterval( 0.0, radius );
}
return map;
}
/*!
\brief Calculate the bounding rect of the plot area
The plot area depends on the zoom parameters.
\param canvasRect Rectangle of the canvas
\return Rectangle for displaying 100% of the plot
*/
QwtDoubleRect QwtPolarPlot::plotRect( const QRect &canvasRect ) const
{
const QwtScaleDiv *sd = scaleDiv( QwtPolar::Radius );
const QwtScaleEngine *se = scaleEngine( QwtPolar::Radius );
const int margin = plotMarginHint();
const QRect cr = canvasRect;
const int radius = qwtMin( cr.width(), cr.height() ) / 2 - margin;
QwtScaleMap map;
map.setTransformation( se->transformation() );
map.setPaintXInterval( 0.0, radius / d_data->zoomFactor );
#if QWT_VERSION < 0x050200
map.setScaleInterval( sd->lBound(), sd->hBound() );
#else
map.setScaleInterval( sd->lowerBound(), sd->upperBound() );
#endif
double v = map.s1();
if ( map.s1() <= map.s2() )
v += d_data->zoomPos.radius();
else
v -= d_data->zoomPos.radius();
v = map.xTransform( v );
const QwtDoublePoint off =
QwtPolarPoint( d_data->zoomPos.azimuth(), v ).toPoint();
QwtDoublePoint center( cr.center().x(), cr.top() + margin + radius );
center -= QwtDoublePoint( off.x(), -off.y() );
QwtDoubleRect rect( 0, 0, 2 * map.p2(), 2 * map.p2() );
rect.moveCenter( center );
return rect;
}