/* sticfigure drawings in asymptote.
 *
 * Copyright (C) 2008-2009 W. Trevor King <wking@drexel.edu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
			
struct StickFigure {
  pair center;
  real height;
  real headHeightRatio;
  real neckHeightRatio;
  real torsoHeightRatio;
  real shoulderHeightRatio;
  real legHeightRatio;
  real centerTorsoRatio;
  real armTorsoRatio;
  real rightArmAngle;
  real leftArmAngle;
  real rightLegAngle;
  real leftLegAngle;
  pen outline;
  pen fill;

  void operator init(pair standsOn=(0,0), real height=10mm) {
    this.height = height;
    this.headHeightRatio = 0.2;
    this.neckHeightRatio = 0.1;
    this.torsoHeightRatio = 0.28;
    this.shoulderHeightRatio = 0.1;
    /* at shoulder width, a leg takes this much height:
     *   1 - head - neck - torso  (opposite legAngle)
     * and this much width:
     *   shoulder/2               (adjavent legAngle)
     */
    this.rightLegAngle = -aTan(
        2*(1-this.headHeightRatio-this.neckHeightRatio-this.torsoHeightRatio)
	/this.shoulderHeightRatio);
    this.leftLegAngle = rightLegAngle;
    this.legHeightRatio = this.shoulderHeightRatio/2/Cos(this.rightLegAngle);
    this.centerTorsoRatio = 0.2;
    this.armTorsoRatio = 1.2;
    this.rightArmAngle = -70;
    this.leftArmAngle = -70;
    this.outline = currentpen;
    this.fill = currentpen;

    this.center = standsOn +
      (0, this.height*(this.legHeightRatio*Sin(-this.rightLegAngle)
		       +this.torsoHeightRatio*this.centerTorsoRatio));
  }

  /* center a fixed torso fraction (centerTorsoRatio) above tail.
   * Everything else located from that point.
   */

  pair tailPos() {
    return this.center
      - (0,this.height*this.torsoHeightRatio*this.centerTorsoRatio);
  }

  pair neckBasePos() {
    return this.tailPos() + (0,this.height*this.torsoHeightRatio);
  }

  pair chinPos() {
    return this.neckBasePos() + (0,this.height*this.neckHeightRatio);
  }

  pair crownPos() {
    return this.chinPos() + (0,this.height*this.headHeightRatio);
  }

  pair headPos() {
    return (this.crownPos() + this.chinPos())/2;
  }

  pair shoulderPos(bool leftSide=false) {
    real sign = 1;
    if (leftSide == true)
      sign = -1;
    return this.neckBasePos() + (sign*this.height*this.shoulderHeightRatio/2,0);
  }

  pair handPos(bool leftSide=false) {
    real len = this.height*this.torsoHeightRatio*this.armTorsoRatio;
    real ang;
    if (leftSide == true) {
      ang = 180 - this.leftArmAngle;
    } else{ 
      ang = this.rightArmAngle;
    }
    return this.shoulderPos(leftSide=leftSide) + len * dir(ang);
  }


  pair footPos(bool leftSide=false) {
    real len = this.height*this.legHeightRatio;
    real ang;
    if (leftSide == true) {
      ang = 180 - this.leftLegAngle;
    } else{ 
      ang = this.rightLegAngle;
    }
    return this.tailPos() + len * dir(ang);
  }

  pair standsOnPos() {
    return (this.footPos() + this.footPos(leftSide=true))/2;
  }

  void standsOn(pair pos) {
    this.center += pos - this.standsOnPos();
  }

  void draw(picture pic=currentpicture) {
    path head =
      shift(this.headPos())
      *scale(this.height*this.headHeightRatio/2)
      *unitcircle;
    path neckAndTorso =
      this.chinPos()
      --this.neckBasePos()
      --this.tailPos();
    path armsAndShoulders =
      this.handPos(leftSide=false)
      --this.shoulderPos(leftSide=false)
      --this.shoulderPos(leftSide=true)
      --this.handPos(leftSide=true);
    path legs =
      this.footPos(leftSide=false)
      --this.tailPos()
      --this.footPos(leftSide=true);
    draw(pic, armsAndShoulders, this.outline);
    draw(pic, legs, this.outline);
    draw(pic, neckAndTorso, this.outline);
    dot(this.handPos(leftSide=false), this.fill);
    dot(this.handPos(leftSide=true), this.fill);
    dot(this.footPos(leftSide=false), this.fill);
    dot(this.footPos(leftSide=true), this.fill);
    filldraw(pic, head, this.fill, this.outline);
  }
}