Geomerative: intersection not accurate

Processing
1

I draw a simple intersection between two rectangles but the result is not accurate.
The simple code is:

import geomerative.*;

void setup() 
{
  size(600, 400); 
  smooth();
  background(255);
  noFill();
  RG.init(this);
  strokeWeight(4);
  RShape R = RShape.createRectangle(100, 50, 100, 100);
  RShape S = RShape.createRectangle(130, 70, 100, 100);
  RShape T = S.intersection(R);
  S=S.diff(T);
  stroke(0,255,0);
  S.draw();
  stroke(255,0,0);
  R.draw();
}

void draw() {
}

The result is this:
immagine_2021-01-19_221801

Why??

2

I’m not sure why, depending on your requirements you might want to try toxiclibs:-

import toxi.geom.*;
import toxi.processing.*;
import java.util.List;

ToxiclibsSupport gfx;

void setup() {
  size(600, 400); 
  smooth();
  background(255);
  noFill();
  strokeWeight(4);
  gfx = new ToxiclibsSupport(this);
  BooleanShapeBuilder builder = new BooleanShapeBuilder(
  BooleanShapeBuilder.Type.UNION);
  stroke(255, 0, 0);
  builder.addShape(new Rect(100, 50, 100, 100));
  stroke(255, 255, 0);
  builder.addShape(new Rect(130, 70, 100, 100));  
  List<Polygon2D> polies = builder.computeShapes();
  for (Polygon2D p : polies) {
    gfx.polygon2D(p);
  }
}

boolean