Piecewise curve approximation for Processing 4 .
Spliner constructs piecewise curves that have the best fit to a list of points. Four algorithms are implemented:
- Quad Bezier curve fitting
- Smooth Fitting
- Least-square fitting
- Polygon fitting
Algorithms by Andrés Solís Montero.
List<PVector> points;
Fitting fitting = new BezierFitting(); // or new LeastSquareFitting(), etc.
List<Shape> beziers = fitting.fitCurve(points);
for (var curve : curves) {
if (curve instanceof CubicCurve) {
var c = (CubicCurve) curve;
bezier(c.getX1(), c.getY1(), c.getCtrlX1(), c.getCtrlY1(), c.getCtrlX2(), c.getCtrlY2(), c.getX2(), c.getY2());
} else { // straight-line segments
var l = (Segment) curve;
line(l.getX1(), l.getY1(), l.getX2(), l.getY2());
}
}
Processing Code...
import processing.javafx.*;
import micycle.spliner.fitting.*;
import micycle.spliner.geom.*;
import java.util.ArrayList;
import java.util.List;
List<PVector> points;
List<Line> curves;
int fittingType = 0;
void setup() {
size(800, 800, FX2D);
colorMode(HSB, 1, 1, 1);
populatePoints();
fit();
}
void draw() {
background(0, 0, 1);
int i = 0;
for (var curve : curves) {
stroke(color(i * (1f / curves.size()), 1, 1));
strokeWeight(10);
if (curve instanceof CubicCurve) {
var c = (CubicCurve) curve;
bezier(c.getX1(), c.getY1(), c.getCtrlX1(), c.getCtrlY1(), c.getCtrlX2(), c.getCtrlY2(), c.getX2(), c.getY2());
stroke(color(0.4, 1, 0.8));
strokeWeight(2);
line(c.getX1(), c.getY1(), c.getCtrlX1(), c.getCtrlY1()); // cp line
line(c.getX2(), c.getY2(), c.getCtrlX2(), c.getCtrlY2()); // cp line
} else { // straight-line segments
var l = (Segment) curve;
line(l.getX1(), l.getY1(), l.getX2(), l.getY2());
}
i ;
}
}
void fit() {
Fitting f = null;
switch (fittingType % 4) {
case 1 :
f = new BezierFitting();
break;
case 0 :
f = new LeastSquareFitting();
break;
case 2 :
f = new PolygonFitting();
break;
case 3 :
f = new SmoothFitting();
break;
}
curves = f.fitCurve(points);
}
void populatePoints() {
points = new ArrayList<>();
for (int x = 0; x < width; x =20) {
points.add(new PVector(x, noise(x frameCount) * height));
}
}
void mousePressed() { // click to fit a new point set
populatePoints();
fit();
}
void keyPressed() { // press to switch fitting algorithm
fittingType ;
fit();
}