void QgsMarkerLineSymbolLayerV2::renderPolylineCentral( const QPolygonF& points, QgsSymbolV2RenderContext& context )
{
if ( points.size() > 0 )
{
// calc length
qreal length = 0;
QPolygonF::const_iterator it = points.constBegin();
QPointF last = *it;
for ( ++it; it != points.constEnd(); ++it )
{
length += sqrt(( last.x() - it->x() ) * ( last.x() - it->x() ) +
( last.y() - it->y() ) * ( last.y() - it->y() ) );
last = *it;
}
// find the segment where the central point lies
it = points.constBegin();
last = *it;
qreal last_at = 0, next_at = 0;
QPointF next;
int segment = 0;
for ( ++it; it != points.constEnd(); ++it )
{
next = *it;
next_at += sqrt(( last.x() - it->x() ) * ( last.x() - it->x() ) +
( last.y() - it->y() ) * ( last.y() - it->y() ) );
if ( next_at >= length / 2 )
break; // we have reached the center
last = *it;
last_at = next_at;
segment++;
}
// find out the central point on segment
MyLine l( last, next ); // for line angle
qreal k = ( length * 0.5 - last_at ) / ( next_at - last_at );
QPointF pt = last + ( next - last ) * k;
// draw the marker
double origAngle = mMarker->angle();
if ( mRotateMarker )
mMarker->setAngle( origAngle + l.angle() * 180 / M_PI );
mMarker->renderPoint( pt, context.feature(), context.renderContext(), -1, context.selected() );
if ( mRotateMarker )
mMarker->setAngle( origAngle );
}
}
void ClipPainterPrivate::clipPolyObject ( const QPolygonF & polygon,
QVector<QPolygonF> & clippedPolyObjects,
bool isClosed )
{
// mDebug() << "ClipPainter enabled." ;
// Only create a new polyObject as soon as we know for sure that
// the current point is on the screen.
QPolygonF clippedPolyObject = QPolygonF();
const QVector<QPointF>::const_iterator itStartPoint = polygon.constBegin();
const QVector<QPointF>::const_iterator itEndPoint = polygon.constEnd();
QVector<QPointF>::const_iterator itPoint = itStartPoint;
// We use a while loop to be able to cover linestrings as well as linear rings:
// Linear rings require to tessellate the path from the last node to the first node
// which isn't really convenient to achieve with a for loop ...
bool processingLastNode = false;
while ( itPoint != itEndPoint ) {
m_currentPoint = (*itPoint);
// mDebug() << "m_currentPoint.x()" << m_currentPoint.x() << "m_currentPOint.y()" << m_currentPoint.y();
// Figure out the sector of the current point.
m_currentSector = sector( m_currentPoint );
// Initialize the variables related to the previous point.
if ( itPoint == itStartPoint && processingLastNode == false ) {
if ( isClosed ) {
m_previousPoint = polygon.last();
// Figure out the sector of the previous point.
m_previousSector = sector( m_previousPoint );
}
else {
m_previousSector = m_currentSector;
}
}
// If the current point reaches a new sector, take care of clipping.
if ( m_currentSector != m_previousSector ) {
if ( m_currentSector == 4 || m_previousSector == 4 ) {
// In this case the current or the previous point is visible on the
// screen but not both. Hence we only need to clip once and require
// only one interpolation for both cases.
clipOnce( clippedPolyObject, clippedPolyObjects, isClosed );
}
else {
// This case mostly deals with lines that reach from one
// sector that is located off screen to another one that
// is located off screen. In this situation the line
// can get clipped once, twice, or not at all.
clipMultiple( clippedPolyObject, clippedPolyObjects, isClosed );
}
m_previousSector = m_currentSector;
}
// If the current point is onscreen, just add it to our final polygon.
if ( m_currentSector == 4 ) {
clippedPolyObject << m_currentPoint;
#ifdef MARBLE_DEBUG
++(m_debugNodeCount);
#endif
}
m_previousPoint = m_currentPoint;
// Now let's handle the case where we have a (closed) polygon and where the
// last point of the polyline is outside the viewport and the start point
// is inside the viewport. This needs special treatment
if ( processingLastNode ) {
break;
}
++itPoint;
if ( itPoint == itEndPoint && isClosed ) {
itPoint = itStartPoint;
processingLastNode = true;
}
}
// Only add the pointer if there's node data available.
if ( !clippedPolyObject.isEmpty() ) {
clippedPolyObjects << clippedPolyObject;
}
}