If I have a line (possibly with some spline interpolation specified), can I extract the interpolated y-value at a given x-value? Thanks!
If I have a line (possibly with some spline interpolation specified), can I extract
Share
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
If I have a line (possibly with some spline interpolation specified), can I extract the interpolated y-value at a given x-value? Thanks!
It’s possible, but there’s not yet a built-in facility for doing so. All of D3’s splines are implemented as piecewise quadratic or cubic Bézier curves (because they are rendered to SVG path elements). You can use de Casteljau’s algorithm for computing the xy-coordinates for a given parameter t in [0,1].
It’s a bit harder to compute y for a given x because it’s possible to have multiple y values for the same x, depending on the curve. For that, I recommend looking at this Bézier curves primer which describes an algorithm for computing a curve-line intersection; this could be simplified for a vertical line (constant x).