OutputIterator clip_range_with_box(Box const& b, Range const& range,
RobustPolicy const&,
OutputIterator out, Strategy const& strategy)
{
if (boost::begin(range) == boost::end(range))
{
return out;
}
typedef typename point_type<OutputLinestring>::type point_type;
OutputLinestring line_out;
typedef typename boost::range_iterator<Range const>::type iterator_type;
iterator_type vertex = boost::begin(range);
for(iterator_type previous = vertex++;
vertex != boost::end(range);
++previous, ++vertex)
{
point_type p1, p2;
geometry::convert(*previous, p1);
geometry::convert(*vertex, p2);
// Clip the segment. Five situations:
// 1. Segment is invisible, finish line if any (shouldn't occur)
// 2. Segment is completely visible. Add (p1)-p2 to line
// 3. Point 1 is invisible (clipped), point 2 is visible. Start new line from p1-p2...
// 4. Point 1 is visible, point 2 is invisible (clipped). End the line with ...p2
// 5. Point 1 and point 2 are both invisible (clipped). Start/finish an independant line p1-p2
//
// This results in:
// a. if p1 is clipped, start new line
// b. if segment is partly or completely visible, add the segment
// c. if p2 is clipped, end the line
bool c1 = false;
bool c2 = false;
model::referring_segment<point_type> s(p1, p2);
if (!strategy.clip_segment(b, s, c1, c2))
{
strategy.apply(line_out, out);
}
else
{
// a. If necessary, finish the line and add a start a new one
if (c1)
{
strategy.apply(line_out, out);
}
// b. Add p1 only if it is the first point, then add p2
if (boost::empty(line_out))
{
detail::overlay::append_no_duplicates(line_out, p1, true);
}
detail::overlay::append_no_duplicates(line_out, p2);
// c. If c2 is clipped, finish the line
if (c2)
{
strategy.apply(line_out, out);
}
}
}
// Add last part
strategy.apply(line_out, out);
return out;
}
