static QPoint cutPoint(QPoint p11, QPoint p12, QPoint p21, QPoint p22)
{
double dx1 = p12.x() - p11.x();
double dy1 = p12.y() - p11.y();
double dx2 = p22.x() - p21.x();
double dy2 = p22.y() - p21.y();
if ( dx1 == 0.0 && dx2 == 0.0 )
return QPoint();
if ( dx1 == 0.0 )
{
const double m = dy2 / dx2;
const double t = p21.y() - m * p21.x();
return QPoint(p11.x(), qwtInt(m * p11.x() + t));
}
if ( dx2 == 0 )
{
const double m = dy1 / dx1;
const double t = p11.y() - m * p11.x();
return QPoint(p21.x(), qwtInt(m * p21.x() + t));
}
const double m1 = dy1 / dx1;
const double t1 = p11.y() - m1 * p11.x();
const double m2 = dy2 / dx2;
const double t2 = p21.y() - m2 * p21.x();
if ( m1 == m2 )
return QPoint();
const double x = ( t2 - t1 ) / ( m1 - m2 );
const double y = t1 + m1 * x;
return QPoint(qwtInt(x), qwtInt(y));
}
/*!
\brief Paint the plot into a given rectangle.
Paint the contents of a QwtPlot instance into a given rectangle.
\param painter Painter
\param plotRect Bounding rectangle
\param pfilter Print filter
\sa QwtPlotPrintFilter
*/
void QwtPlot::print(QPainter *painter, const QRect &plotRect,
const QwtPlotPrintFilter &pfilter) const
{
int axis;
if ( painter == 0 || !painter->isActive() ||
!plotRect.isValid() || size().isNull() )
return;
painter->save();
// All paint operations need to be scaled according to
// the paint device metrics.
QwtPainter::setMetricsMap(this, painter->device());
#if QT_VERSION < 300
if ( painter->device()->isExtDev() )
{
QPaintDeviceMetrics metrics(painter->device());
if ( metrics.logicalDpiX() == 72 && metrics.logicalDpiY() == 72 )
{
// In Qt 2.x QPrinter returns hardcoded wrong metrics.
// So scaling won´t work: we reset to screen resolution
QwtPainter::setMetricsMap(this, this);
}
}
#endif
const QwtMetricsMap &metricsMap = QwtPainter::metricsMap();
// It is almost impossible to integrate into the Qt layout
// framework, when using different fonts for printing
// and screen. To avoid writing different and Qt unconform
// layout engines we change the widget attributes, print and
// reset the widget attributes again. This way we produce a lot of
// useless layout events ...
pfilter.apply((QwtPlot *)this);
int baseLineDists[QwtPlot::axisCnt];
if ( !(pfilter.options() & QwtPlotPrintFilter::PrintCanvasBackground) )
{
// In case of no background we set the backbone of
// the scale on the frame of the canvas.
for (axis = 0; axis < QwtPlot::axisCnt; axis++ )
{
if ( d_scale[axis] )
{
baseLineDists[axis] = d_scale[axis]->baseLineDist();
d_scale[axis]->setBaselineDist(0);
}
}
}
// Calculate the layout for the print.
int layoutOptions = QwtPlotLayout::IgnoreScrollbars
| QwtPlotLayout::IgnoreFrames;
if ( !(pfilter.options() & QwtPlotPrintFilter::PrintMargin) )
layoutOptions |= QwtPlotLayout::IgnoreMargin;
if ( !(pfilter.options() & QwtPlotPrintFilter::PrintLegend) )
layoutOptions |= QwtPlotLayout::IgnoreLegend;
d_layout->activate(this, QwtPainter::metricsMap().deviceToLayout(plotRect),
layoutOptions);
if ((pfilter.options() & QwtPlotPrintFilter::PrintTitle)
&& (!d_lblTitle->text().isEmpty()))
{
printTitle(painter, d_layout->titleRect());
}
if ( (pfilter.options() & QwtPlotPrintFilter::PrintLegend)
&& !d_legend->isEmpty() )
{
printLegend(painter, d_layout->legendRect());
}
for ( axis = 0; axis < QwtPlot::axisCnt; axis++ )
{
if (d_scale[axis])
{
int baseDist = d_scale[axis]->baseLineDist();
int startDist, endDist;
d_scale[axis]->minBorderDist(startDist, endDist);
printScale(painter, axis, startDist, endDist,
baseDist, d_layout->scaleRect(axis));
}
}
const QRect canvasRect = metricsMap.layoutToDevice(d_layout->canvasRect());
// When using QwtPainter all sizes where computed in pixel
// coordinates and scaled by QwtPainter later. This limits
// the precision to screen resolution. A much better solution
// is to scale the maps and print in unlimited resolution.
QwtArray<QwtDiMap> map(axisCnt);
for (axis = 0; axis < axisCnt; axis++)
{
const QwtScaleDiv &scaleDiv = d_as[axis].scaleDiv();
map[axis].setDblRange(scaleDiv.lBound(),
scaleDiv.hBound(), scaleDiv.logScale());
double from, to;
if ( axisEnabled(axis) )
{
const int sDist = d_scale[axis]->startBorderDist();
const int eDist = d_scale[axis]->endBorderDist();
const QRect &scaleRect = d_layout->scaleRect(axis);
if ( axis == xTop || axis == xBottom )
{
from = metricsMap.layoutToDeviceX(scaleRect.left() + sDist);
to = metricsMap.layoutToDeviceX(scaleRect.right() - eDist);
}
else
{
from = metricsMap.layoutToDeviceY(scaleRect.bottom() - sDist);
to = metricsMap.layoutToDeviceY(scaleRect.top() + eDist);
}
}
else
{
const int margin = plotLayout()->canvasMargin(axis);
const QRect &canvasRect = plotLayout()->canvasRect();
if ( axis == yLeft || axis == yRight )
{
from = metricsMap.layoutToDeviceX(canvasRect.bottom() - margin);
to = metricsMap.layoutToDeviceX(canvasRect.top() + margin);
}
else
{
from = metricsMap.layoutToDeviceY(canvasRect.left() + margin);
to = metricsMap.layoutToDeviceY(canvasRect.right() - margin);
}
}
map[axis].setIntRange( qwtInt(from), qwtInt(to));
}
// The maps are already scaled.
QwtPainter::setMetricsMap(painter->device(), painter->device());
printCanvas(painter, canvasRect, map, pfilter);
QwtPainter::resetMetricsMap();
d_layout->invalidate();
// reset all widgets with their original attributes.
if ( !(pfilter.options() & QwtPlotPrintFilter::PrintCanvasBackground) )
{
// restore the previous base line dists
for (axis = 0; axis < QwtPlot::axisCnt; axis++ )
{
if ( d_scale[axis] )
d_scale[axis]->setBaselineDist(baseLineDists[axis]);
}
}
pfilter.reset((QwtPlot *)this);
painter->restore();
}