code: public void setCurve (float x1, float y1, float ctrlx, float ctrly, float x2, float y2) {
          this.x1 = x1;
          this.y1 = y1;
          this.ctrlx = ctrlx;
          this.ctrly = ctrly;
          this.x2 = x2;
          this.y2 = y2;
      }
docs: Configures the start, control, and end points for this curve.