bezier

Convert polynomial curve to Bezier Curve control points

由 心不动则不痛 提交于 2019-12-25 14:34:09
问题 How do I compute the control points given a curve in the form of power form? Say I have p(t)=(x(t),y(t)) and 4 control points. x(t) = 2t y(t) = (t^3)+3(t^2) 回答1: You can always convert from power basis to Bernstein basis. This is always doable and will give you the precise result. Refer to section 3.3 of this link (http://cagd.cs.byu.edu/~557/text/ch3.pdf) for details. EDIT: Since the above link is no longer available, I am listing the formula below: where M is the degree of the Berstein

how to draw a curve using bezierCurveTo dynamically?

由 谁都会走 提交于 2019-12-25 11:34:43
问题 I am stuck at point.what I want is to draw a curve on mouse move(hair like bend).here is my code.Right now I am just able to draw a straight line I don`t know where the problem is,but i guess it might be regarding function calling.any help is welcome!!! <html> <body> <canvas id="myCanvas" width="500" height="800"></canvas> <script src="common.js"></script> </body> </html> common.js //variables to get the mouse position var x1= 0, y1= 0, x2= 0, y2=0; // co-ordinates of bezierCurveTo() var sx

How to find intersecting Y values along a bezier spline?

由 纵然是瞬间 提交于 2019-12-25 05:16:10
问题 It's been a while since I did any maths* of this kind, so perhaps someone can answer this for me. I don't think this question is exactly what I want, because I am trying to find intersections for precise x values. So I have a spline which goes from X,Y to XX,YY, with control points at each end. I think I would be correct in saying it will be a quadratic curve (the curve will not cross itself). I plan on using the path routines from the given graphics library (currently thinking HTML5 canvas)

Cubic bezier curve arc length is always zero

由 别等时光非礼了梦想. 提交于 2019-12-25 02:09:56
问题 I've written the following code to calculate the length of a cubic bezier curve. I got the idea from Calculate the arclength, curve length of a cubic bezier curve. Why is not working?. The problem is it always produces a length of zero. public Vector2 SegmentAtPoint(int segmentIndex, float t) { t = Mathf.Clamp01(t); float oneMinusT = 1f - t; return oneMinusT * oneMinusT * oneMinusT * points[segmentIndex * 3] + 3f * oneMinusT * oneMinusT * t * points[segmentIndex * 3 + 1] + 3f * oneMinusT * t

Why does a QuadraticBezierSegment render differently between drawing with a line and animating with a DoubleAnimationUsingPath.PathGeometry?

由 ≡放荡痞女 提交于 2019-12-24 18:36:34
问题 I have defined a QuadraticBezierSegment object as the Data property of a Path object: <Path Stroke="Red" StrokeThickness="5"> <Path.Data> <PathGeometry> <PathFigure StartPoint="450,250" IsClosed="False"> <QuadraticBezierSegment Point1="245,-50" Point2="0,25" /> </PathFigure> </PathGeometry> </Path.Data> </Path> It is shown below in red, and shows the curve that I expected.: However, when this same curve is used in a path animation, the path of the animated element is NOTHING like the path of

How to get t for average distance of Bézier curve

由 自作多情 提交于 2019-12-24 15:33:05
问题 I am calculating the interpolation position of Bézier curve by using the formula: pow(1 - t, 2) * start + 2.0 * (1 - t) * t * control + t * t * end The problem is that if I linear step the t by for example 0.1 per segment, the length of segment on the Bézier curve is not average. Is there any way to get the corresponding array of t for getting average or approximately average length of the segment on the curve. 回答1: It seems you want an approximate parametrization by arc length. For the

Given an X co-ordinate, how do I calculate the Y co-ordinate for a point so that it rests on a Bezier Curve

由 我只是一个虾纸丫 提交于 2019-12-24 13:26:30
问题 I have a point (circled in pink) which has a known X co-ordinate and a known Y co-ordinate but the Y co-ordinate is incorrect. It is currently resting upon the point where the target bezier curve (the curve partially in a white square) would be if it were a line between its two points. I need to calculate the correct Y co-ordinate for my circled point so that it ends up on the red cross. I am a C# programmer and not a mathematician so if this answer could be expressed in code or with an

Draw 2 bezier curves through 3 points to mimic a circle arc

由 我们两清 提交于 2019-12-24 11:38:03
问题 I have three points that are not on the same line, originally I want to draw a circle arc through these three points, which I did. But chrome is actually not drawing real circle but using several bezier curves to pretend it is circle, because bezier curves are cheap. If chrome is doing that as a middle man, why ain't I drawing circle-like bezier myself (two bezier, from point 1 to middle point, middle point to point 3)? That would be much cleaner, and cheap ( 2 compared to unknown number of

Find Affine transformation matrix between two Shapes(SVG Paths)

由 孤人 提交于 2019-12-23 23:01:07
问题 I have two Shapes, each defined as a single SVG Path. I want to find if Shape A is an Affine Transform of Shape B and also compute/find the Affine transform matrix. My current approach computes the consecutive Angles between off curve and on curve points to find if they are transformed shapes. This works for translate,scale,rotate operations. But does not work for sheared Shapes. Any proper mathematical approaches are available? 回答1: You can find matrix of affine transform between any triplet

How to Drawing a curve line(peaks) using list of x,y coordinates

由 て烟熏妆下的殇ゞ 提交于 2019-12-23 17:10:00
问题 I have a list of x,y points which printed,display an uneven peak curve line. The above image was generated by just painting the points on a java paint component. I used the following way to paint them on a paint component. g.drawline(pointX,pointY,pointX,pointY) Are there better ways to paint such wave line? I checked some of the similar questions,often they need to print a curve or peak,but my line is not always a peak as some times its flats out and other times they are bizarre. 回答1: The
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