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By : Seb
Date : October 25 2020, 07:29 PM
Any of those help There are a number of ways of accomplishing what you're seeing, depending on how you'd like it to behave. I'll explain some of the simpler methods of modifying a Bezier curve via point on curve manipulation.
The first thing to do is figure out the parameter value (t) where the user clicked on the curve. This is generally going to be an approximation. If you're doing pixel or sub-pixel rendering of the Bezier, then just record for every pixel what the t value was and use that. If you're tessellating into line segments, see which line segment is closest, find the t values of the two end points, and lerp the t value according to the distance along the line. code : ## Drawing part of a Bézier curve by reusing a basic Bézier-curve-function?

By : DHessing
Date : March 29 2020, 07:55 AM
it should still fix some issue What you need is the De Casteljau algorithm. This will allow you to split your curve into whatever segments you'd like.
However, since you're dealing with just cubic curves, I'd like to suggest a slightly easier to use formulation that'll give you a segment from t0 to t1 where 0 <= t0 <= t1 <= 1. Here's some pseudocode:
code :
``````u0 = 1.0 - t0
u1 = 1.0 - t1

qxa =  x1*u0*u0 + bx1*2*t0*u0 + bx2*t0*t0
qxb =  x1*u1*u1 + bx1*2*t1*u1 + bx2*t1*t1
qxc = bx1*u0*u0 + bx2*2*t0*u0 +  x2*t0*t0
qxd = bx1*u1*u1 + bx2*2*t1*u1 +  x2*t1*t1

qya =  y1*u0*u0 + by1*2*t0*u0 + by2*t0*t0
qyb =  y1*u1*u1 + by1*2*t1*u1 + by2*t1*t1
qyc = by1*u0*u0 + by2*2*t0*u0 +  y2*t0*t0
qyd = by1*u1*u1 + by2*2*t1*u1 +  y2*t1*t1

xa = qxa*u0 + qxc*t0
xb = qxa*u1 + qxc*t1
xc = qxb*u0 + qxd*t0
xd = qxb*u1 + qxd*t1

ya = qya*u0 + qyc*t0
yb = qya*u1 + qyc*t1
yc = qyb*u0 + qyd*t0
yd = qyb*u1 + qyd*t1
`````` ## Drag and drop in as3 on specific path (ex bezier curve)

By : user1862145
Date : March 29 2020, 07:55 AM
I hope this helps . As in your Kirupa example, in the MouseMove handler you'll take the moment-by-moment x and y of the dragged item and recalculate them. To confine the item to a vertical line, for example, you would set x back to the x the item began with, while freeing y to follow the mouse.
In your case, you need an x-and-y recalculation that can 1) determine whether the move is or is not on your path, and 2) if not, shift it to the nearest point on that path (whatever "nearest" means to you). ## convert bezier curve with N point to many cubic bezier curve

By : ThaneG
Date : March 29 2020, 07:55 AM
Hope this helps Math theory: you cannot do this. An nth order Bezier curve cannot be represented as any number of (n-1)th order Bezier curves, because the curvatures cannot be faithfully represented. You can approximate it, but you won't get an identical result.
Practice: you can cut up your 48th order curve into sections of simple curve, where all the control points are on the same side of the start/end baseline, and the midpoint on the curve w.r.t your control variable is roughly in the center of the convex hull for the curve. For such curves, low level curves are reasonable approximations. You can do this by finding the inflections on the curve using the first, second, etc. derivative roots for your 48th order curve (see http://pomax.github.com/bezierinfo/#derivatives and http://pomax.github.com/bezierinfo/#splitting) and then running de Casteljau's algorithm to split up the curve between each inflection point's control variable value. You can then approximate each of the resultant subcurves with cubic curves and the result will look pretty close (or look identical at the pixel level) to your original curve. ## How to convert quadratic bezier curve code into cubic bezier curve?

By : Arham
Date : March 29 2020, 07:55 AM
hope this fix your issue For cubic Bézier curve, as you see in the link you shared, the green lines are obtained from the same procedure as the quadratic one. the differences are: you have two green lines, and then you need to calculate a blue line based on them. So the for loop changes as:
code :
``````for( float i = 0 ; i < 1 ; i += 0.01 )
{
// The Green Lines
xa = getPt( x1 , x2 , i );
ya = getPt( y1 , y2 , i );
xb = getPt( x2 , x3 , i );
yb = getPt( y2 , y3 , i );
xc = getPt( x3 , x4 , i );
yc = getPt( y3 , y4 , i );

// The Blue Line
xm = getPt( xa , xb , i );
ym = getPt( ya , yb , i );
xn = getPt( xb , xc , i );
yn = getPt( yb , yc , i );

// The Black Dot
x = getPt( xm , xn , i );
y = getPt( ym , yn , i );

drawPixel( x , y , COLOR_RED );
}
`````` ## Draw a curve (bezier curve) between two lat long points on google maps android

By : twanmal
Date : March 29 2020, 07:55 AM
hope this fix your issue This answer is somewhat specative, but I suggest that nothing you are seeing is actually wrong or even unexpected. As you know, the Earth is round, but Google Maps (and computer screens) are inherently flat and two dimensional. The way we begin creating a flat 2D map of the Earth is by carving up a globe like this: 