Handle[] g_h = new Handle[HANDLE_NB]; // They are initialized in setup()
boolean g_bDragging;

void draw()
{
  background(#AADDFF);
  boolean bDragging = false;
  for (int i = 0; i < HANDLE_NB; i++)
  {
    g_h[i].Update(g_bDragging);
    if (g_h[i].IsDragged())
    {
	bDragging = true;
	g_h[i].Move();
    }
    g_h[i].Draw();
  }
  g_bDragging = bDragging;
}
 

class Handle
{
  float m_x, m_y;  // Position of handle
  int m_size;  // Diameter of handle
  // Stuff...

  private boolean m_bIsHovered, m_bDragged;
  private float m_clickDX, m_clickDY;

  boolean IsDragged()
  {
    return m_bDragged;
  }

  void Update(boolean bAlreadyDragging)
  {
    m_bIsHovered = dist(mouseX, mouseY, m_x, m_y) <= m_size / 2;
    if (!bAlreadyDragging && mousePressed && mouseButton == LEFT && m_bIsHovered)
    {
	m_bDragged = true;
	m_clickDX = mouseX - m_x;
	m_clickDY = mouseY - m_y;
    }
    if (!mousePressed)
    {
	m_bDragged = false;
    }
  }

  void Move()
  {
    if (m_bDragged)
    {
	m_x = mouseX - m_clickDX;
	m_y = mouseY - m_clickDY;
    }
  }
}