void QwtPainter::drawPolyline(QPainter *painter, const QwtPolygonF &pa)
{
QRect clipRect;
const bool deviceClipping = isClippingNeeded(painter, clipRect);
QwtPolygonF cpa = d_metricsMap.layoutToDevice(pa);
if ( deviceClipping )
cpa = QwtClipper::clipPolygonF(clipRect, cpa);
#if QT_VERSION >= 0x040000
bool doSplit = false;
const QPaintEngine *pe = painter->paintEngine();
if ( pe && pe->type() == QPaintEngine::Raster &&
painter->pen().width() >= 2 )
{
/*
The raster paint engine seems to use some algo with O(n*n).
( Qt 4.3 is better than Qt 4.2, but remains unacceptable)
To work around this problem, we have to split the polygon into
smaller pieces.
*/
doSplit = true;
}
if ( doSplit )
{
const int numPoints = cpa.size();
const QPointF *points = cpa.data();
const int splitSize = 20;
for ( int i = 0; i < numPoints; i += splitSize )
{
const int n = qwtMin(splitSize + 1, cpa.size() - i);
painter->drawPolyline(points + i, n);
}
}
else
#endif
painter->drawPolyline(cpa);
}
// modified by Ion Vasilief in order to use floating point coordinates
void QwtPlotCurve::drawLines(QPainter *painter,
const QwtScaleMap &xMap, const QwtScaleMap &yMap,
int from, int to) const
{
int size = to - from + 1;
if ( size <= 0 )
return;
QwtPolygonF polyline;
if ( ( d_data->attributes & Fitted ) && d_data->curveFitter )
{
// Transform x and y values to window coordinates
// to avoid a distinction between linear and
// logarithmic scales.
QPolygonF points(size);
for (int i = from; i <= to; i++)
{
QwtDoublePoint &p = points[i];
p.setX( xMap.xTransform(x(i)) );
p.setY( yMap.xTransform(y(i)) );
}
points = d_data->curveFitter->fitCurve(points);
size = points.size();
if ( size == 0 )
return;
// Round QwtDoublePoints to QPoints
// When Qwt support for Qt3 has been dropped (Qwt 6.x)
// we will use a doubles for painting and the following
// step will be obsolete.
polyline.resize(size);
const QwtDoublePoint *p = points.data();
QPointF *pl = polyline.data();
if ( d_data->paintAttributes & PaintFiltered )
{
QPointF pp(p[0].x(), p[0].y());
pl[0] = pp;
int count = 1;
for (int i = 1; i < size; i++)
{
const QPointF pi(p[i].x(), p[i].y());
if ( pi != pp )
{
pl[count++] = pi;
pp = pi;
}
}
if ( count != size )
polyline.resize(count);
}
else
{
for ( int i = 0; i < size; i++ )
{
pl[i].setX( p[i].x() );
pl[i].setY( p[i].y() );
}
}
}
else
{
polyline.resize(size);
if ( d_data->paintAttributes & PaintFiltered )
{
QPointF pp( xMap.xTransform(x(from)), yMap.xTransform(y(from)) );
polyline[0] = pp;
int count = 1;
for (int i = from + 1; i <= to; i++)
{
const QPointF pi(xMap.xTransform(x(i)), yMap.xTransform(y(i)));
if ( pi != pp )
{
polyline[count] = pi;
count++;
pp = pi;
}
}
if ( count != size )
polyline.resize(count);
}
else
{
for (int i = from; i <= to; i++)
{
const QPointF pi(xMap.xTransform(x(i)), yMap.xTransform(y(i)));
polyline[i - from] = pi;
}
}
}
if ( d_data->paintAttributes & ClipPolygons )
polyline = QwtClipper::clipPolygonF(painter->window(), polyline);
QwtPainter::drawPolyline(painter, polyline);
if ( d_data->brush.style() != Qt::NoBrush )
fillCurve(painter, xMap, yMap, polyline);
}
static inline QwtDoubleRect boundingRect(const QwtPolygonF &polygon)
{
#if QT_VERSION < 0x040000
if (polygon.isEmpty())
return QwtDoubleRect(0, 0, 0, 0);
register const QwtDoublePoint *pd = polygon.data();
double minx, maxx, miny, maxy;
minx = maxx = pd->x();
miny = maxy = pd->y();
pd++;
for (uint i = 1; i < polygon.size(); i++, pd++)
{
if (pd->x() < minx)
minx = pd->x();
else if (pd->x() > maxx)
maxx = pd->x();
if (pd->y() < miny)
miny = pd->y();
else if (pd->y() > maxy)
maxy = pd->y();
}
return QwtDoubleRect(minx, miny, maxx - minx, maxy - miny);
#else
return polygon.boundingRect();
#endif
}
