Geometry Generation
import java.awt.*; import java.awt.event.*; import java.text.*; import javax.swing.*; import no.geosoft.cc.geometry.Geometry; import no.geosoft.cc.graphics.*; /** * G demo program. Demonstrates: * * <ul> * <li> A math application * <li> Polyline performance * <li> Geometry generation * </ul> * * @author <a href="mailto:[email protected] ">Jacob Dreyer</a> */ public class Demo20 extends JFrame implements ActionListener { private JButton addLevelButton_; private JButton removeLevelButton_; private JLabel nEdgesLabel_; private JLabel lengthLabel_; private JLabel areaLabel_; private KochSnowflake kochSnowflake_; public Demo20 () { super ( "G Graphics Library - Demo 20" ) ; setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE ) ; JPanel controlPanel = new JPanel () ; addLevelButton_ = new JButton ( "+" ) ; addLevelButton_.addActionListener ( this ) ; controlPanel.add ( addLevelButton_ ) ; removeLevelButton_ = new JButton ( "-" ) ; removeLevelButton_.addActionListener ( this ) ; controlPanel.add ( removeLevelButton_ ) ; nEdgesLabel_ = new JLabel () ; controlPanel.add ( nEdgesLabel_ ) ; lengthLabel_ = new JLabel () ; controlPanel.add ( lengthLabel_ ) ; areaLabel_ = new JLabel () ; controlPanel.add ( areaLabel_ ) ; getContentPane () .add ( controlPanel, BorderLayout.NORTH ) ; // Create the graphic canvas GWindow window = new GWindow ( new Color ( 255 , 255 , 255 )) ; getContentPane () .add ( window.getCanvas () , BorderLayout.CENTER ) ; // Create scene with default viewport and world extent settings GScene scene = new GScene ( window ) ; double w0 [] = { 0.0 , 0.0 , 0.0 } ; double w1 [] = { 1.0 , 0.0 , 0.0 } ; double w2 [] = { 0.0 , 1.0 , 0.0 } ; scene.setWorldExtent ( w0, w1, w2 ) ; // Create the graphics object and add to the scene kochSnowflake_ = new KochSnowflake () ; scene.add ( kochSnowflake_ ) ; pack () ; setSize ( new Dimension ( 500 , 500 )) ; setVisible ( true ) ; window.startInteraction ( new ZoomInteraction ( scene )) ; refresh () ; } public void actionPerformed ( ActionEvent event ) { if ( event.getSource () == addLevelButton_ ) kochSnowflake_.addLevel () ; else kochSnowflake_.removeLevel () ; refresh () ; } public void refresh () { nEdgesLabel_.setText ( "#edges = " + kochSnowflake_.getNEdges ()) ; DecimalFormat format = new DecimalFormat ( "0.00000" ) ; double length = kochSnowflake_.computeLength () ; lengthLabel_.setText ( " Length = " + format.format ( length )) ; double area = kochSnowflake_.computeArea () ; areaLabel_.setText ( " Area = " + format.format ( area )) ; kochSnowflake_.refresh () ; } /** * Defines the geometry and presentation for the sample * graphic object. */ private class KochSnowflake extends GObject { private GSegment curve_; private double [] geometry_; KochSnowflake () { GStyle style = new GStyle () ; style.setForegroundColor ( new Color ( 255 , 0 , 0 )) ; style.setBackgroundColor ( new Color ( 255 , 255 , 0 )) ; setStyle ( style ) ; curve_ = new GSegment () ; geometry_ = new double [] { 0.2 , 0.2 , 0.8 , 0.2 , 0.5 , 0.2 + 0.6 * Math.sin ( Math.PI / 3.0 ) , 0.2 , 0.2 } ; addSegment ( curve_ ) ; } public int getNEdges () { return geometry_.length / 2 - 1 ; } public double computeLength () { double length = 0 ; for ( int i = 0 ; i < geometry_.length - 2 ; i += 2 ) { length += Geometry.length ( geometry_ [ i+ 0 ] , geometry_ [ i+ 1 ] , geometry_ [ i+ 2 ] , geometry_ [ i+ 3 ]) ; } return length; } public double computeArea () { return Geometry.computePolygonArea ( geometry_ ) ; } public void addLevel () { int nLegs = geometry_.length / 2 - 1 ; int nPoints = nLegs * 4 * 2 + 2 ; double [] geometry = new double [ nPoints ] ; int j = 0 ; for ( int i = 0 ; i < nLegs* 2 ; i += 2 ) { geometry [ j+ 0 ] = geometry_ [ i+ 0 ] ; geometry [ j+ 1 ] = geometry_ [ i+ 1 ] ; double [] v0 = Geometry.computePointOnLine ( geometry_ [ i+ 0 ] , geometry_ [ i+ 1 ] , geometry_ [ i+ 2 ] , geometry_ [ i+ 3 ] , 1.0 / 3.0 ) ; geometry [ j+ 2 ] = v0 [ 0 ] ; geometry [ j+ 3 ] = v0 [ 1 ] ; double [] v1 = Geometry.computePointOnLine ( geometry_ [ i+ 0 ] , geometry_ [ i+ 1 ] , geometry_ [ i+ 2 ] , geometry_ [ i+ 3 ] , 2.0 / 3.0 ) ; geometry [ j+ 6 ] = v1 [ 0 ] ; geometry [ j+ 7 ] = v1 [ 1 ] ; double length = Geometry.length ( v0 [ 0 ] , v0 [ 1 ] , v1 [ 0 ] , v1 [ 1 ]) ; double dx = geometry_ [ i+ 2 ] - geometry_ [ i+ 0 ] ; double dy = geometry_ [ i+ 3 ] - geometry_ [ i+ 1 ] ; double l = Math.sqrt ( dx * dx + dy * dy ) ; double angle = Math.acos ( dx / l ) ; if ( dy < 0 ) angle = 2.0 * Math.PI - angle; angle -= Math.PI / 3.0 ; geometry [ j+ 4 ] = geometry [ j+ 2 ] + length * Math.cos ( angle ) ; geometry [ j+ 5 ] = geometry [ j+ 3 ] + length * Math.sin ( angle ) ; j+= 8 ; } geometry [ geometry.length- 2 ] = geometry [ 0 ] ; geometry [ geometry.length- 1 ] = geometry [ 1 ] ; geometry_ = geometry; redraw () ; } public void removeLevel () { int nLegs = geometry_.length / 2 - 1 ; if ( nLegs == 3 ) return ; int nPoints = nLegs / 4 * 2 + 2 ; double [] geometry = new double [ nPoints ] ; int j = 0 ; for ( int i = 0 ; i < geometry.length - 2 ; i += 2 ) { geometry [ i+ 0 ] = geometry_ [ j+ 0 ] ; geometry [ i+ 1 ] = geometry_ [ j+ 1 ] ; j += 8 ; } geometry [ geometry.length- 2 ] = geometry [ 0 ] ; geometry [ geometry.length- 1 ] = geometry [ 1 ] ; geometry_ = geometry; redraw () ; } public void draw () { curve_.setGeometryXy ( geometry_ ) ; } } public static void main ( String [] args ) { new Demo20 () ; } }
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