+ if (aProjection && anEndAttr->pnt()->distance(aProjection) > tolerance) {
+ // issue #855: trying to update only not-updated coordinate if it is possible
+ if (abs(myXEndBefore - anEndAttr->x()) < 1.e-10) { // keep Y unchanged
+ double aVy = aCenterAttr->y() - anEndAttr->y();
+ double aVy2 = aVy * aVy;
+ double aR2 = aCircleForArc->radius() * aCircleForArc->radius();
+ if (aVy2 <= aR2) {
+ double aDX = sqrt(aR2 - aVy * aVy);
+ if (anEndAttr->x() > aCenterAttr->x())
+ aProjection->setX(aCenterAttr->x() + aDX);
+ else
+ aProjection->setX(aCenterAttr->x() - aDX);
+ aProjection->setY(anEndAttr->y());
+ }
+ } else if (abs(myYEndBefore - anEndAttr->y()) < 1.e-10) { // keep X unchanged
+ double aVx = aCenterAttr->x() - anEndAttr->x();
+ double aVx2 = aVx * aVx;
+ double aR2 = aCircleForArc->radius() * aCircleForArc->radius();
+ if (aVx2 <= aR2) {
+ double aDY = sqrt(aR2 - aVx * aVx);
+ if (anEndAttr->y() > aCenterAttr->y())
+ aProjection->setY(aCenterAttr->y() + aDY);
+ else
+ aProjection->setY(aCenterAttr->y() - aDY);
+ aProjection->setX(anEndAttr->x());
+ }
+ }
+