Example 1 2

[Examples 1] 0 1 2 3 4 5 6 7 8 9
Two intersecting circles
// two intersecting circles

float x0; float y0; float r0;
float x1; float y1; float r1;

float x2; float y2;
float x3; float y3;
float x4; float y4;

float a; float b;
float h; float d;

void setup() {
  size(360, 240);
  smooth();
  stroke(0);
  x0 = 120; y0 = 120; r0 = 80;
  x1 = 240; y1 = 120; r1 = 80;
} //setup

void draw() {
  background(207);
  strokeWeight(3);
  noFill();
  ellipse(x0, y0, 2*r0, 2*r0);
  ellipse(x1, y1, 2*r1, 2*r1);
  d = dist(x0, y0, x1, y1);
  a = (r0*r0 - r1*r1 + d*d)/(2*d);
  x2 = x0 + a*(x1 - x0) / d;
  x4 = x2;
  h = sqrt(r0*r0 - a*a);
  y2 = y0 + h;
  y4 = y0 - h;
  strokeWeight(1);
  fill(255);

  ellipse(x0, y0, 5, 5); // P1
  ellipse(x1, y1, 5, 5); // P2
  ellipse(x2, y2, 5, 5); // P3
  ellipse(x4, y4, 5, 5); // P4
} //draw

void mouseDragged()
{
  if (dist(mouseX, mouseY, x0, y0) <= 15) {
    x0 = mouseX;
    //y0 = mouseY;
  } else if (dist(mouseX, mouseY, x1, y1) <= 15) {
    x1 = mouseX;
    //y1 = mouseY;
  }
} //mouseDragged