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fix for euclidean distance from point to line segment

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[SVN r73371]
This commit is contained in:
Luke Simonson
2011-07-26 02:51:42 +00:00
parent f2a3351f7b
commit 0dad75432c
1 changed files with 8 additions and 14 deletions
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22
include/boost/polygon/directed_line_segment_concept.hpp
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@@ -303,19 +303,6 @@ namespace boost { namespace polygon{
euclidean_distance(const segment_type& segment,
typename directed_line_segment_traits<segment_type>::point_type position) {
typedef typename directed_line_segment_distance_type<segment_type>::type Unit;
Unit result1 = euclidean_distance(low(segment), high(segment));
Unit result2 = euclidean_distance(low(segment), position);
Unit result3 = euclidean_distance(high(segment), position);
if(result2 > result1) {
if(result3*result3 < result2*result2 - result1*result1)
return result3;
}
else if(result3 > result1) {
if(result2*result2 < result3*result3 - result1*result1)
return result2;
}
if(on_above_or_below(segment, position) == 0)
return 0.0; //I don't want to return non-zero distance if the predicate returns on the line
Unit x1 = x(low(segment));
Unit y1 = y(low(segment));
Unit x2 = x(high(segment));
@@ -326,7 +313,14 @@ namespace boost { namespace polygon{
Unit B = Y - y1;
Unit C = x2 - x1;
Unit D = y2 - y1;
Unit denom = sqrt(C * C + D * D);
Unit length_sq = C * C + D * D;
Unit param = (A * C + B * D)/length_sq;
if(param > 1.0) {
return euclidean_distance(high(segment), position);
} else if(param < 0.0) {
return euclidean_distance(low(segment), position);
}
Unit denom = sqrt(length_sq);
if(denom == 0.0)
return 0.0;
Unit result = (A * D - C * B) / denom;