[solved] Add spline with control points via Simple API

[Irene]

Hello,

Is it possible to add a spline with control points (instead of fit points) via Simple API?
I am trying to create a script for a sewing pattern drawing. So far it works, but i would need control point splines. The script is created from a C# tool, a kind of PoC for sewing pattern "macros".

Best thanks and regards
Irene

[andrew]

Not directly through the Simple API, but for example like this:

Code: Select all

var sp = new RSpline();
sp.setPeriodic(false);    // true for closed, periodic
sp.appendControlPoint(new RVector(x1, y1));
sp.appendControlPoint(new RVector(x2, y2));
...
addShape(sp);

You might want to wrap this into your own function for convenience.

[Irene]

Hello Andrew,

Many thanks for the quick reply
I don't get an error so i suppose it works somehow, but the spline does not get drawn. Is there anything else to be done?
The spline should show up inside the green rectangle.

Code: Select all

var sp = new RSpline();
sp.setPeriodic(false);
sp.appendControlPoint(new RVector(138, 81.44444));
sp.appendControlPoint(new RVector(129.83333, 81.44444));
sp.appendControlPoint(new RVector(129.83333, 85));
addShape(sp);

I attach my full script just in case. Adding lines and points works like a charm.

Best thanks and regards
Irene

[andrew]

The spline degree is 3 (cubic) by default which means the spline needs at least 4 control points. You can add another control point or change the degree to quadratic using setDegree:

Code: Select all

var sp = new RSpline();
sp.setPeriodic(false);
sp.setDegree(2);
sp.appendControlPoint(new RVector(138, 81.44444));
sp.appendControlPoint(new RVector(129.83333, 81.44444));
sp.appendControlPoint(new RVector(129.83333, 85));
addShape(sp);

[Irene]

Hello Andrew,

Works like a charm, thank you very much

Best regards
Irene

[Paul D]

Very helpful thread. Thanks.

[CVH]

May I add that a closed spline with a minimal point count doesn't display correctly immediately after creation.
Although on manual creation the preview looks OK.

Code: Select all

var sp = new RSpline();
sp.setPeriodic(true);
sp.setDegree(2);
sp.appendControlPoint(new RVector(138, 81.44444));
sp.appendControlPoint(new RVector(129.83333, 81.44444));
sp.appendControlPoint(new RVector(129.83333, 85));
addShape(sp);

It shows fine when you save the file and reload it.
https://qcad.org/bugtracker/index.php?d ... sk_id=2453

@Paul D.
Remark that an open spline in degree 2 with 3 control points is a parabola or a part of that.

Regards,
CVH