How to draw ellipses in Scilab with orientation?

The existing functions xarc draw an ellipse, but the semi-major axes are aligned with the plot axes. Is there a way to 'rotate' the ellipse so it has an orientation that is not with the plot axes?

Solution

If the arc is the only element drawn in the axes, then you can actually use xarc() to generate it, and then rotate the whole axes:

clf
xarc(0, 1, 3, 1, 0, 310*64)
isoview
gca().rotation_angles(2) = 70;

But, its likely not the case. Then the arc must be generated as a polyline object, and then rotate() can be used to rotate it:

clf
alpha = 0:1:310;
[a, b, xc, yc] = (3, 1, 2, 2);
x = xc + a*cosd(alpha);
y = yc + b*sind(alpha);
r = 20;   // rotation angle in °
xyR = rotate([x;y], r/180*%pi, [xc ; yc])';
plot(xyR(:,1), xyR(:,2))