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Linestring/polygon overlay, third phase (including segments along polygon's border)

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[SVN r75564]
This commit is contained in:
Barend Gehrels
2011-11-20 11:50:06 +00:00
parent 5c62dfcf06
commit 95c5d6f945
1 changed files with 23 additions and 25 deletions
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48
include/boost/geometry/algorithms/detail/overlay/follow.hpp
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@@ -64,7 +64,17 @@ class follow
template <typename Turn, typename Operation>
static inline bool is_entering(Turn const& turn, Operation const& op)
{
return op.operation == operation_intersection;
// (Blocked means: blocked for polygon/polygon intersection, because
// they are reversed. But for polygon/line it is similar to continue)
switch(op.operation)
{
case operation_intersection :
case operation_continue :
case operation_blocked :
return true;
}
return false;
}
template <typename Turn, typename Operation>
@@ -74,20 +84,10 @@ class follow
{
if (op.operation == operation_union)
{
if (turn.method == method_crosses)
{
return true;
}
if (entered)
{
return true;
}
if (first)
{
// Check if first point of line is inside polygon
return geometry::within(linestring[0], polygon);
}
return entered
|| turn.method == method_crosses
|| (first && geometry::within(linestring[0], polygon))
;
}
return false;
}
@@ -100,21 +100,19 @@ class follow
{
if (turn.method == method_crosses)
{
// The normal case, this is completely covered with entering/leaving
// so stay out of this time consuming "within"
return false;
}
if (op.operation == operation_intersection)
switch(op.operation)
{
if (entered)
{
return true;
}
if (first)
{
// Check if first point of line is inside polygon
return geometry::within(linestring[0], polygon);
}
case operation_intersection :
case operation_continue :
case operation_blocked :
return entered || (first && geometry::within(linestring[0], polygon));
}
return false;
}