JSFiddle - React, Tailwind, and code Playground
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<script type="text/processing">
/**
* Convert a Catmull-Rom multipoint curve
* to a cubic Bezier multipoint curve.
*/
// our points
ArrayList<PVector> points;
// curve tightness
float cmr_tightness;
// cmr-tightness to bezier-control-offset factor
float cmr_to_bezier;
// preamble
void setup() {
size(800,400);
points = new ArrayList<PVector>();
ellipseMode(CENTER);
noFill();
stroke(0);
noLoop();
setTightness(0);
}
// set catmull-rom tightness, and corresponding
// bezier control point offset factor. These are
// correlated with a relatively simple function.
void setTightness(float v) {
curveTightness(v);
cmr_tightness = v;
cmr_to_bezier = -6/(v-1);
}
// do we have enough points to draw a catmull-rom curve?
boolean allpoints = false;
// draw the points collected so far,
// connecting them as Catmull-Rom interpolation
// curve if there's more than three, and showig
// the corresponding cubic Bezier curve overlayed.
void draw() {
background(255);
curveTightness(cmr_tightness);
// Draw the catmull-rom curve.
strokeWeight(2);
stroke(0);
if(allpoints) { beginShape(); }
for(PVector p: points) {
ellipse(p.x, p.y, 5, 5);
if(allpoints) curveVertex(p.x,p.y);
}
if(allpoints) { endShape(); }
// Then draw its bezier approximation.
if(allpoints) {
strokeWeight(1);
stroke(255,0,0);
beginShape();
vertex(points.get(1).x, points.get(1).y);
for(int i=1, last=points.size()-2; i<last; i++) {
PVector pT = points.get(i-1);
PVector p1 = points.get(i);
PVector p2 = points.get(i+1);
PVector p3 = points.get(i+2);
// Every catmull rom point has a tangent
// equal to dx(p-1,p+1)/dy(p-1,p+1), with
// the curve tightness determining the
// strength of the control point, i.e. how
// far from the on-curve point it lies.
float dx1 = (p2.x - pT.x)/cmr_to_bezier;
float dy1 = (p2.y - pT.y)/cmr_to_bezier;
float dx2 = (p3.x -...