Esempio n. 1
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  /**
   * Compute the position of a sprite if attached to an edge.
   *
   * @param sprite The sprite.
   * @param pos Where to stored the computed position, if null, the position is created.
   * @param units The units the computed position must be given into.
   * @return The same instance as pos, or a new one if pos was null.
   */
  protected Point2D.Double getSpritePositionEdge(
      GraphicSprite sprite, Point2D.Double pos, Units units) {
    if (pos == null) pos = new Point2D.Double();

    GraphicEdge edge = sprite.getEdgeAttachment();

    if (edge.isCurve()) {
      double ctrl[] = edge.getControlPoints();
      Point2 p0 = new Point2(edge.from.getX(), edge.from.getY());
      Point2 p1 = new Point2(ctrl[0], ctrl[1]);
      Point2 p2 = new Point2(ctrl[1], ctrl[2]);
      Point2 p3 = new Point2(edge.to.getX(), edge.to.getY());
      Vector2 perp = CubicCurve.perpendicular(p0, p1, p2, p3, sprite.getX());
      double y = metrics.lengthToGu(sprite.getY(), sprite.getUnits());

      perp.normalize();
      perp.scalarMult(y);

      pos.x = CubicCurve.eval(p0.x, p1.x, p2.x, p3.x, sprite.getX()) - perp.data[0];
      pos.y = CubicCurve.eval(p0.y, p1.y, p2.y, p3.y, sprite.getX()) - perp.data[1];
    } else {
      double x = ((GraphicNode) edge.getSourceNode()).x;
      double y = ((GraphicNode) edge.getSourceNode()).y;
      double dx = ((GraphicNode) edge.getTargetNode()).x - x;
      double dy = ((GraphicNode) edge.getTargetNode()).y - y;
      double d = sprite.getX(); // Percent on the edge.
      double o = metrics.lengthToGu(sprite.getY(), sprite.getUnits());
      // Offset from the position given by percent, perpendicular to the
      // edge.

      d = d > 1 ? 1 : d;
      d = d < 0 ? 0 : d;

      x += dx * d;
      y += dy * d;

      d = (double) Math.sqrt(dx * dx + dy * dy);
      dx /= d;
      dy /= d;

      x += -dy * o;
      y += dx * o;

      pos.x = x;
      pos.y = y;

      if (units == Units.PX) {
        Tx.transform(pos, pos);
      }
    }

    return pos;
  }