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FCLT#58797 Versie 4.18 Geen afrondfouten/oveflow bij Centroid berekening als zowel x en y rond INT_MAX

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svn path=/Slnkdwf/trunk/; revision=43710
This commit is contained in:
Jos Groot Lipman
2019-08-11 20:28:38 +00:00
parent 84c58d2f59
commit 8f93947541
1 changed files with 11 additions and 9 deletions
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20
SlnkDWFImpl/SLNKContourImpl.cpp
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@@ -276,11 +276,13 @@ Subject 1.02: How do I find the distance from a point to a line?
int i;
double area = 0;
for (i=0;i<pg.count();i++) {
const WT_Logical_Point &dwfPtA = pg.points()[i];
const WT_Logical_Point &dwfPtB = pg.points()[(i + 1) % pg.count()];
area += (double)dwfPtA.m_x * dwfPtB.m_y;
area -= (double)dwfPtA.m_y * dwfPtB.m_x;
const int j = (i + 1) % pg.count();
const double Xi = pg.points()[i].m_x, // Alles naar double anders krijgen wel overflows
Yi = pg.points()[i].m_y,
Xj = pg.points()[j].m_x,
Yj = pg.points()[j].m_y;
//area += Xi*Yj - Xj*Yi; // heeft bij X en Y beide rond INT_MAX zelfs met double afrondproblemen
area += (Xi - Xj)*Yj + Xj*(Yj - Yi);
}
area /= 2;
@@ -337,10 +339,10 @@ WT_Logical_Point CSLNKContourImpl::LabelPosition(LABELPOS pos /*= LABEL_DEFAULT*
double dDWFarea = 0; // Die ook meteen uitrekenen
for (i = 0; i < pg.count(); i++) {
j = (i + 1) % pg.count();
double Xi=pg.points()[i].m_x, // Alles naar double anders krijgen wel overflows
Yi=pg.points()[i].m_y,
Xj=pg.points()[j].m_x,
Yj=pg.points()[j].m_y;
const double Xi = pg.points()[i].m_x, // Alles naar double anders krijgen wel overflows
Yi = pg.points()[i].m_y,
Xj = pg.points()[j].m_x,
Yj = pg.points()[j].m_y;
//double dArea = Xi*Yj - Xj*Yi; // heeft bij X en Y beide rond INT_MAX zelfs met double afrondproblemen
double dArea = (Xi-Xj)*Yj + Xj*(Yj-Yi);
dDWFarea += dArea;