static void ellipse_params(float Ux, float Uy, float Vx, float Vy,
float &A, float &B, float &C, float &F, float &umax, float &vmax)
{
A = Vx * Vx + Vy * Vy;
B = -2.0f * (Ux * Vx + Uy * Vy);
C = Ux * Ux + Uy * Uy;
F = A * C - B * B * 0.25f;
float factor = (F != 0.0f ? (float)(EWA_MAXIDX + 1) / F : 0.0f);
A *= factor;
B *= factor;
C *= factor;
F = (float)(EWA_MAXIDX + 1);
ellipse_bounds(A, B, C, sqrtf(F), umax, vmax);
}
//------------------------------------------------------------------------------
// Name: make_ellipse_helper
// Desc:
//------------------------------------------------------------------------------
void GraphNode::make_ellipse_helper(node_t *node, QPainterPath &path) const {
auto poly = static_cast<polygon_t *>(ND_shape_info(node));
if(poly->peripheries != 1) {
qWarning("unsupported number of peripheries %d", poly->peripheries);
}
const int sides = poly->sides;
const pointf* vertices = poly->vertices;
QPolygonF polygon;
for (int side = 0; side < sides; side++) {
polygon.append(graph_->gToQ(vertices[side], false));
}
QRectF ellipse_bounds(polygon[0], polygon[1]);
for (int i = 0; i < poly->peripheries; ++i) {
path.addEllipse(ellipse_bounds.adjusted(-2 * i, 2 * i, 2 * i, -2 * i));
}
}
