f@0: /*  
f@0:  CCmI Editor - A Collaborative Cross-Modal Diagram Editing Tool
f@0: 	  
f@0:  Copyright (C) 2002 Cay S. Horstmann (http://horstmann.com)
f@0:  Copyright (C) 2011  Queen Mary University of London (http://ccmi.eecs.qmul.ac.uk/)
f@0: 
f@0:  This program is free software: you can redistribute it and/or modify
f@0:  it under the terms of the GNU General Public License as published by
f@0:  the Free Software Foundation, either version 3 of the License, or
f@0:  (at your option) any later version.
f@0: 
f@0:  This program is distributed in the hope that it will be useful,
f@0:  but WITHOUT ANY WARRANTY; without even the implied warranty of
f@0:  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
f@0:  GNU General Public License for more details.
f@0: 
f@0:  You should have received a copy of the GNU General Public License
f@0:  along with this program.  If not, see <http://www.gnu.org/licenses/>.
f@0: */
f@0: 
f@0: package uk.ac.qmul.eecs.ccmi.simpletemplate;
f@0: 
f@0: import java.awt.BasicStroke;
f@0: import java.awt.Color;
f@0: import java.awt.Graphics2D;
f@0: import java.awt.Stroke;
f@0: import java.awt.geom.GeneralPath;
f@0: import java.awt.geom.Point2D;
f@0: import java.io.IOException;
f@0: 
f@0: /**
f@0:    This class defines arrowheads of diverse shapes.
f@0: */
f@0: public enum ArrowHead {
f@0: 	TAIL("Tail"),
f@0: 	TRIANGLE("Triangle"),
f@0:     BLACK_TRIANGLE("Black Triangle"),
f@0:     V("V"),
f@0: 	HALF_V("Half V"),
f@0: 	DIAMOND("Diamond"),
f@0: 	BLACK_DIAMOND("Black Diamond");
f@0: 	
f@0:    private ArrowHead(String name) {
f@0: 	   this.lowerCaseName = name;
f@0:    }
f@0:    
f@0:    public static ArrowHead getArrowHeadFromString(String arrowHeadName) throws IOException{
f@0: 	   ArrowHead h;
f@0: 	   String name = arrowHeadName.toUpperCase().replace(" ", "_");
f@0: 	   try {
f@0: 		   h = ArrowHead.valueOf(name);
f@0: 	   }catch (IllegalArgumentException e){
f@0: 		   throw new IOException(e);
f@0: 	   }
f@0: 	   return h;
f@0:    }
f@0:    
f@0:    @Override
f@0:    public String toString(){
f@0: 	   return lowerCaseName;
f@0:    }
f@0:    
f@0:    /**
f@0:       Draws the arrowhead.
f@0:       @param g2 the graphics context
f@0:       @param p a point on the axis of the arrow head
f@0:       @param q the end point of the arrow head
f@0:    */
f@0:    public void draw(Graphics2D g2, Point2D p, Point2D q){
f@0:       GeneralPath path = getPath(p, q);
f@0:       Color oldColor = g2.getColor();
f@0:       if (this == BLACK_DIAMOND || this == BLACK_TRIANGLE)
f@0:          g2.setColor(Color.BLACK);
f@0:       else
f@0:          g2.setColor(Color.WHITE);
f@0:       g2.fill(path);
f@0:       g2.setColor(oldColor);
f@0:       Stroke oldStroke = g2.getStroke();
f@0:       g2.setStroke(new BasicStroke());
f@0:       g2.draw(path);
f@0:       g2.setStroke(oldStroke);
f@0:    }
f@0: 
f@0:    /**
f@0:       Gets the path of the arrowhead
f@0:       @param p a point on the axis of the arrow head
f@0:       @param q the end point of the arrow head
f@0:       @return the path
f@0:    */
f@0:    public GeneralPath getPath(Point2D p, Point2D q){
f@0:       GeneralPath path = new GeneralPath();
f@0:       final double ARROW_ANGLE = Math.PI / 6;
f@0:       final double ARROW_LENGTH = 10;
f@0: 
f@0:       double dx = q.getX() - p.getX();
f@0:       double dy = q.getY() - p.getY();
f@0:       double angle = Math.atan2(dy, dx);
f@0:       double x1 = q.getX() 
f@0:          - ARROW_LENGTH * Math.cos(angle + ARROW_ANGLE);
f@0:       double y1 = q.getY() 
f@0:          - ARROW_LENGTH * Math.sin(angle + ARROW_ANGLE);
f@0:       double x2 = q.getX() 
f@0:          - ARROW_LENGTH * Math.cos(angle - ARROW_ANGLE);
f@0:       double y2 = q.getY() 
f@0:          - ARROW_LENGTH * Math.sin(angle - ARROW_ANGLE);
f@0: 
f@0:       path.moveTo((float)q.getX(), (float)q.getY());
f@0:       path.lineTo((float)x1, (float)y1);
f@0:       if (this == V)
f@0:       {
f@0:          path.moveTo((float)x2, (float)y2);
f@0:          path.lineTo((float)q.getX(), (float)q.getY());
f@0:       }
f@0:       else if (this == TRIANGLE || this == BLACK_TRIANGLE)
f@0:       {
f@0:          path.lineTo((float)x2, (float)y2);
f@0:          path.closePath();                  
f@0:       }
f@0:       else if (this == DIAMOND || this == BLACK_DIAMOND)
f@0:       {
f@0:          double x3 = x2 - ARROW_LENGTH * Math.cos(angle + ARROW_ANGLE);
f@0:          double y3 = y2 - ARROW_LENGTH * Math.sin(angle + ARROW_ANGLE);
f@0:          path.lineTo((float)x3, (float)y3);
f@0:          path.lineTo((float)x2, (float)y2);
f@0:          path.closePath();         
f@0:       }      
f@0:       return path;
f@0:    }
f@0:    
f@0:    private String lowerCaseName;
f@0: }