bezier

Calculate a 2D spline curve in R

我只是一个虾纸丫 提交于 2019-11-30 23:49:02
问题 I'm trying to calculate a Bezier-like spline curve that passes through a sequence of x-y coordinates. An example would be like the following output from the cscvn function in Matlab (example link): I believe the (no longer maintained) grid package used to do this ( grid.xspline function?), but I haven't been able to install an archived version of the package, and don't find any examples exactly along the lines of what I would like. The bezier package also looks promising, but it is very slow

Approximating nonparametric cubic Bezier

穿精又带淫゛_ 提交于 2019-11-30 21:06:58
What is the best way to approximate a cubic Bezier curve? Ideally I would want a function y(x) which would give the exact y value for any given x, but this would involve solving a cubic equation for every x value, which is too slow for my needs, and there may be numerical stability issues as well with this approach. Would this be a good solution? Die in Sente Just solve the cubic. If you're talking about Bezier plane curves, where x(t) and y(t) are cubic polynomials, then y(x) might be undefined or have multiple values. An extreme degenerate case would be the line x= 1.0, which can be

Calculate the horizon of a curved face? - Not extrema

╄→гoц情女王★ 提交于 2019-11-30 21:06:09
I need to find the 2 points of the visual horizon , of a curved face. I have: XYZ of the 4 corner points XYZ of the 2 curved edge bezier points And I need to calculate either: XY of the 2 horizon points XYZ of the 2 horizon points Note: I got a solution the last time I asked this question, but it only found the extrema of the curves, not the horizon points , which changes based on the position and rotation of both curves in respect to each other. You don't say how your surface is defined, only that it is bounded by two quadratic Bézier curves. There are lots of ways to build such a surface,

calculating parameters for defining subsections of quadratic bezier curves

一世执手 提交于 2019-11-30 15:13:01
I have a quadratic bezier curve described as (startX, startY) to (anchorX, anchorY) and using a control point (controlX, controlY). I have two questions: (1) I want to determine y points on that curve based on an x point. (2) Then, given a line-segment on my bezier (defined by two intermediary points on my bezier curve (startX', startY', anchorX', anchorY')), I want to know the control point for that line-segment so that it overlaps the original bezier exactly. Why? I want this information for an optimization. I am drawing lots of horizontal beziers. When the beziers are larger than the screen

How to approximate a half-cosine curve with bezier paths in SVG?

六月ゝ 毕业季﹏ 提交于 2019-11-30 13:54:43
问题 Suppose I want to approximate a half-cosine curve in SVG using bezier paths. The half cosine should look like this: and runs from [x0,y0] (the left-hand control point) to [x1,y1] (the right-hand one). How can I find an acceptable set of coefficients for a good approximation of this function? Bonus question : how is it possible to generalize the formula for, for example, a quarter of cosine? Please note that I don't want to approximate the cosine with a series of interconnected segments, I'd

Point Sequence Interpolation

心不动则不痛 提交于 2019-11-30 13:14:04
Given an arbitrary sequence of points in space, how would you produce a smooth continuous interpolation between them? 2D and 3D solutions are welcome. Solutions that produce a list of points at arbitrary granularity and solutions that produce control points for bezier curves are also appreciated. Also, it would be cool to see an iterative solution that could approximate early sections of the curve as it received the points, so you could draw with it. The Catmull-Rom spline is guaranteed to pass through all the control points. I find this to be handier than trying to adjust intermediate control

Divide bezier curve into two equal halves

半腔热情 提交于 2019-11-30 12:33:51
问题 I have the bezier curves between 2 points. I'd like to cut all curves into two equal half. One of my idea is if I can control 't' value I'll draw 2 curves by t = [0,0.5] and t = [0.5,1] but I don't know how. Below is my code. I won't mind any other idea or suggestion <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html;

Cubic bezier curves - get Y for given X

对着背影说爱祢 提交于 2019-11-30 12:15:19
I have a cubic bezier curve where the first and last points are given (namely P0(0,0) and P3(1,1)). The other two points are defined like this: cubic-bezier(0.25, 0.1, 0.25, 1.0) (X1, Y1, X2, Y2, also those values must not be smaller or larger than 0 or 1, respectively) Now what would I have to do to get the Y coordinate for a given X, assuming there's only one? (I know that under certain circumstances there can be multiple values, but let's just put them aside. I'm not doing rocket science over here, I just want to be able to get Y multiple times per second to do transitions) I managed to dig

Drawing a Topographical Map

守給你的承諾、 提交于 2019-11-30 10:12:32
问题 I've been working on a visualization project for 2-dimensional continuous data. It's the kind of thing you could use to study elevation data or temperature patterns on a 2D map. At its core, it's really a way of flattening 3-dimensions into two-dimensions-plus-color. In my particular field of study, I'm not actually working with geographical elevation data, but it's a good metaphor, so I'll stick with it throughout this post. Anyhow, at this point, I have a "continuous color" renderer that I

Find all the points of a cubic bezier curve in javascript

爱⌒轻易说出口 提交于 2019-11-30 10:06:06
I have a cubic bezier with 2 control points. Starting point and control points are known. Need to get all the points of the curve, given the control, starting and ending points. What I wanna to achieve is ..given a value i from 1 to length of curve.. get the X and Y and alpha (angle) of each point in that position. I cannot find a good reference or working code for that. I'm using javascript. Rahul Banerjee If I understand correctly, you are trying to determine the position and slope (tangent to the curve) of the Bezier, at every point. Let's assume that your start point is (ax, ay), the end