RArc RArc::createTangential(const RVector& startPoint, const RVector& pos,
double direction, double radius) {
RArc arc;
arc.radius = radius;
// orthogonal to base entity:
RVector ortho;
ortho.setPolar(radius, direction + M_PI/2.0);
// two possible center points for arc:
RVector center1 = startPoint + ortho;
RVector center2 = startPoint - ortho;
if (center1.getDistanceTo(pos) < center2.getDistanceTo(pos)) {
arc.center = center1;
} else {
arc.center = center2;
}
// angles:
arc.startAngle = arc.center.getAngleTo(startPoint);
arc.endAngle = arc.center.getAngleTo(pos);
// handle arc direction:
arc.reversed = false;
double diff = RMath::getNormalizedAngle(arc.getDirection1() - direction);
if (fabs(diff-M_PI) < 1.0e-1) {
arc.reversed = true;
}
return arc;
}
void RExporter::exportArcSegment(const RArc& arc, bool allowForZeroLength) {
if (allowForZeroLength && arc.isFullCircle()) {
exportLineSegment(RLine(arc.getStartPoint(), arc.getEndPoint()), arc.getDirection1());
return;
}
double segmentLength;
if (pixelSizeHint>0.0) {
// approximate arc with segments with the length of 2 pixels:
segmentLength = pixelSizeHint * 2;
}
else {
segmentLength = arc.getRadius() / 40.0;
}
// avoid a segment length of 0:
if (segmentLength<1.0e-4) {
segmentLength = 1.0e-4;
}
double a1 = arc.getStartAngle();
double a2 = arc.getEndAngle();
RVector center = arc.getCenter();
double radius = arc.getRadius();
double aStep;
if (radius<1.0e-3) {
aStep = 0.1;
}
else {
aStep = segmentLength / radius;
if (aStep>1.0) {
aStep = 1.0;
}
double minAStep = RSettings::getMinArcAngleStep();
if (draftMode) {
minAStep *= 4;
}
if (aStep<minAStep) {
aStep = minAStep;
}
}
RVector prev = arc.getStartPoint();
RVector ci;
double a;
if (!arc.isReversed()) {
// Arc Counterclockwise:
if(a1>a2-RS::AngleTolerance) {
a2+=2*M_PI;
}
for (a=a1+aStep; a<=a2; a+=aStep) {
ci.x = center.x + cos(a) * radius;
ci.y = center.y + sin(a) * radius;
exportLineSegment(RLine(prev, ci), a+M_PI_2);
prev = ci;
}
} else {
// Arc Clockwise:
if (a1<a2+RS::AngleTolerance) {
a2-=2*M_PI;
}
for (a=a1-aStep; a>=a2; a-=aStep) {
ci.x = center.x + cos(a) * radius;
ci.y = center.y + sin(a) * radius;
exportLineSegment(RLine(prev, ci), a+M_PI_2);
prev = ci;
}
}
this->exportLineSegment(RLine(prev, arc.getEndPoint()), arc.getEndAngle()+M_PI_2);
}