float MapScale::getScreenRotation(float angle, const atools::geo::Pos& position, float zoomDistanceMeter) const
{
if(viewport != nullptr && viewport->projection() == Marble::Spherical && zoomDistanceMeter > 50)
{
// Get screen coordinates or origin
Marble::GeoDataCoordinates coords(position.getLonX(), position.getLatY(), 0., GeoDataCoordinates::Degree);
bool globeHidesPoint = false, globeHidesPointEnd = false;
double x = 0., y = 0., xEnd = 0., yEnd = 0.;
bool visible = viewport->screenCoordinates(coords, x, y, globeHidesPoint);
if(globeHidesPoint || !visible)
// Not visible
return map::INVALID_COURSE_VALUE;
// Use a tenth of the zoom distance which results in a screen length of 15 - 30 pixel
// Calculate endpoint in global coordinate system
Pos end = position.endpoint(zoomDistanceMeter / 10.f, angle);
end.normalize();
// Calculate screen coordinates of endpoint
Marble::GeoDataCoordinates endcoords(end.getLonX(), end.getLatY(), 0., GeoDataCoordinates::Degree);
viewport->screenCoordinates(endcoords, xEnd, yEnd, globeHidesPointEnd);
if(!globeHidesPointEnd)
{
QLineF line(x, y, xEnd, yEnd);
// qDebug() << Q_FUNC_INFO << line.length();
if(line.length() > 5.)
angle = atools::geo::normalizeCourse(
static_cast<float>(atools::geo::angleFromQt(line.angle())));
else
return map::INVALID_COURSE_VALUE;
}
else
// Hide if endpoint is not visible
return map::INVALID_COURSE_VALUE;
}
return angle;
}
