static inline void qwtDrawPolyline( QPainter *painter,
const T *points, int pointCount, bool polylineSplitting )
{
bool doSplit = false;
if ( polylineSplitting && pointCount > 3 )
{
const QPaintEngine *pe = painter->paintEngine();
if ( pe && pe->type() == QPaintEngine::Raster )
{
if ( painter->pen().width() <= 1 )
{
#if QT_VERSION < 0x040800
if ( painter->renderHints() & QPainter::Antialiasing )
{
/*
all versions <= 4.7 have issues with
antialiased lines
*/
doSplit = true;
}
#else
// all version < 4.8 don't have the bug for
// short lines below 2 pixels difference
// in height and width
doSplit = qwtIsRasterPaintEngineBuggy();
#endif
}
else
{
/*
Raster paint engine is much faster when splitting
the polygon, but of course we might see some issues where
the pieces are joining
*/
doSplit = true;
}
}
}
if ( doSplit )
{
QPen pen = painter->pen();
const int splitSize = 6;
if ( pen.width() <= 1 && pen.isSolid() && qwtIsRasterPaintEngineBuggy()
&& !( painter->renderHints() & QPainter::Antialiasing ) )
{
int k = 0;
for ( int i = k + 1; i < pointCount; i++ )
{
const QPointF &p1 = points[i-1];
const QPointF &p2 = points[i];
const bool isBad = ( qAbs( p2.y() - p1.y() ) <= 1 )
&& qAbs( p2.x() - p1.x() ) <= 1;
if ( isBad || ( i - k >= splitSize ) )
{
painter->drawPolyline( points + k, i - k + 1 );
k = i;
}
}
painter->drawPolyline( points + k, pointCount - k );
}
else
{
for ( int i = 0; i < pointCount; i += splitSize )
{
const int n = qMin( splitSize + 1, pointCount - i );
painter->drawPolyline( points + i, n );
}
}
}
else
{
painter->drawPolyline( points, pointCount );
}
}
