Hilbert空間遞歸演示

Hilbert空間填充曲線在圖像採樣等方面十分有用關於什麼希爾伯特

空間填充曲線看這裏：http://en.wikipedia.org/wiki/Hilbert_curve

程序效果:

模擬Hilbert空間填充曲線效果，點擊鼠標自動疊加！運行效果截圖

Hilbert源程序代碼：

package com.gloomyfish.p_w_picpath.hilbert; 
        
import java.awt.Color; 
import java.awt.Graphics; 
import java.awt.Point; 
        
public class Hilbert { 
            
    public static final int WHEELSIZE = 1024; 
            
    // four edges 
    public static final int NORTH = 0; 
    public static final int EAST = 90; 
    public static final int SOUTH = 180; 
    public static final int WEST = 270; 
        
    // four corners 
    public static final int NE = 45; 
    public static final int SE = 135; 
    public static final int SW = 225; 
    public static final int NW = 315; 
            
    // attributes 
    private Point location; 
    private Color[] colorWheel; 
    private int colorIdx; 
        
    public Hilbert() { 
        // build color lookup table 
        this.colorWheel = new Color[1024]; 
        for (int i = 0; i < 128; ++i) 
            this.colorWheel[i] = new Color(0, 255 - i, i); 
        for (int j = 128; j < 256; ++j) 
            this.colorWheel[j] = new Color(0, j, j); 
        for (int k = 0; k < 256; ++k) 
            this.colorWheel[(k + 256)] = new Color(0, 255 - k, 255); 
        for (int l = 0; l < 128; ++l) 
            this.colorWheel[(l + 512)] = new Color(0, l, 255 - l); 
        for (int i1 = 0; i1 < 128; ++i1) 
            this.colorWheel[(i1 + 640)] = new Color(0, 127 - i1, 127 - i1); 
        for (int i2 = 0; i2 < 256; ++i2) 
            this.colorWheel[(i2 + 768)] = new Color(0, i2, 0); 
        this.colorIdx = 0; 
    } 
        
    public void process(Graphics graphic, int level, int width, int height) { 
        this.location = null; 
        if(level > 32 )  
        { 
            graphic.drawString("could get max depth is 32!", 40, 40); 
            return; 
        } 
        hilbert(graphic, level, 0, 0, width, height, 0, 225); 
    } 
        
    public void hilbert(Graphics g, int depth, int startx, int starty, int width, int height, int startgray, int endgray) { 
        int centerX = width / 2; 
        int centerY = height / 2; 
        if (depth == 0) { 
            if (this.location != null) { 
                g.setColor(this.colorWheel[this.colorIdx]); 
                g.drawLine(this.location.x, this.location.y, 
                        startx + centerX, starty + centerY); 
                if (++this.colorIdx >= 1024) 
                    this.colorIdx = 0; 
            } 
            this.location = new Point(startx + centerX, starty + centerY); 
            return; 
        } 
        
        switch (startgray) { 
        case 0: 
            if (endgray == 225) { 
                hilbert(g, depth - 1, startx, starty + centerY, centerX, centerY, 90, 225); // bottom-left 
                hilbert(g, depth - 1, startx, starty, centerX, centerY, 0, 225); // upper-left 
                hilbert(g, depth - 1, startx + centerX, starty, centerX, centerY, 0, 225); // upper-right 
                hilbert(g, depth - 1, startx + centerX, starty + centerY, centerX, centerY, 270, 45); // bottom-right 
                return; 
            } 
        
            if (endgray != 135) 
                return; 
            hilbert(g, depth - 1, startx + centerX, starty + centerY, centerX, centerY, 270, 135); 
            hilbert(g, depth - 1, startx + centerX, starty, centerX, centerY, 0, 135); 
            hilbert(g, depth - 1, startx, starty, centerX, centerY, 0, 135); 
            hilbert(g, depth - 1, startx, starty + centerY, centerX, centerY, 90, 315); 
        
            return; 
        case 90: 
            if (endgray == 315) { 
                hilbert(g, depth - 1, startx, starty, centerX, 
                        centerY, 180, 315); 
                hilbert(g, depth - 1, startx + centerX, starty, 
                        centerX, centerY, 90, 315); 
                hilbert(g, depth - 1, startx + centerX, starty 
                        + centerY, centerX, centerY, 90, 315); 
                hilbert(g, depth - 1, startx, starty + centerY, 
                        centerX, centerY, 0, 135); 
        
                return; 
            } 
        
            if (endgray != 225) 
                return; 
            hilbert(g, depth - 1, startx, starty + centerY, centerX, 
                    centerY, 0, 225); 
            hilbert(g, depth - 1, startx + centerX, starty + centerY, 
                    centerX, centerY, 90, 225); 
            hilbert(g, depth - 1, startx + centerX, starty, centerX, 
                    centerY, 90, 225); 
            hilbert(g, depth - 1, startx, starty, centerX, centerY, 
                    180, 45); 
        
            return; 
        case 180: 
            if (endgray == 45) { 
                hilbert(g, depth - 1, startx + centerX, starty, 
                        centerX, centerY, 270, 45); 
                hilbert(g, depth - 1, startx + centerX, starty 
                        + centerY, centerX, centerY, 180, 45); 
                hilbert(g, depth - 1, startx, starty + centerY, 
                        centerX, centerY, 180, 45); 
                hilbert(g, depth - 1, startx, starty, centerX, 
                        centerY, 90, 225); 
        
                return; 
            } 
        
            if (endgray != 315) 
                return; 
            hilbert(g, depth - 1, startx, starty, centerX, centerY, 
                    90, 315); 
            hilbert(g, depth - 1, startx, starty + centerY, centerX, 
                    centerY, 180, 315); 
            hilbert(g, depth - 1, startx + centerX, starty + centerY, 
                    centerX, centerY, 180, 315); 
            hilbert(g, depth - 1, startx + centerX, starty, centerX, 
                    centerY, 270, 135); 
        
            return; 
        case 270: 
            if (endgray == 45) { 
                hilbert(g, depth - 1, startx + centerX, starty, 
                        centerX, centerY, 180, 45); 
                hilbert(g, depth - 1, startx, starty, centerX, 
                        centerY, 270, 45); 
                hilbert(g, depth - 1, startx, starty + centerY, 
                        centerX, centerY, 270, 45); 
                hilbert(g, depth - 1, startx + centerX, starty 
                        + centerY, centerX, centerY, 0, 225); 
        
                return; 
            } 
        
            if (endgray != 135) 
                return; 
            hilbert(g, depth - 1, startx + centerX, starty + centerY, 
                    centerX, centerY, 0, 135); 
            hilbert(g, depth - 1, startx, starty + centerY, centerX, 
                    centerY, 270, 135); 
            hilbert(g, depth - 1, startx, starty, centerX, centerY, 
                    270, 135); 
            hilbert(g, depth - 1, startx + centerX, starty, centerX, 
                    centerY, 180, 315); 
        
            return; 
        } 
    } 
}

UI部分代碼：

package com.gloomyfish.p_w_picpath.hilbert; 
    
import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.Dimension; 
import java.awt.Graphics; 
import java.awt.event.MouseEvent; 
import java.awt.event.MouseListener; 
    
import javax.swing.JComponent; 
import javax.swing.JFrame; 
    
public class HilbertUI extends JComponent implements MouseListener { 
    /**
     * 
     */ 
    private static final long serialVersionUID = 1L; 
    private int level; 
    private Hilbert hilbert; 
    private Dimension size; 
    
    public HilbertUI() { 
        this.level = 1; 
        size = new Dimension(405, 405); 
        this.hilbert = new Hilbert(); 
        addMouseListener(this); 
    } 
    
    @Override 
    protected void paintComponent(Graphics g) { 
        g.setColor(Color.BLACK); 
        g.clearRect(0, 0, (int)size.getWidth(), (int)size.getHeight()); 
        this.hilbert.process(g, this.level, (int)size.getWidth()-5, (int)size.getHeight()-5); 
    } 
    
    @Override 
    public Dimension getPreferredSize() { 
        return size; 
    } 
    
    @Override 
    public Dimension getMaximumSize() { 
        return size; 
    } 
    
    @Override 
    public Dimension getMinimumSize() { 
        return size; 
    } 
    
    public void mousePressed(MouseEvent paramMouseEvent) { 
    } 
    
    public void mouseEntered(MouseEvent paramMouseEvent) { 
    } 
    
    public void mouseExited(MouseEvent paramMouseEvent) { 
    } 
    
    public void mouseReleased(MouseEvent paramMouseEvent) { 
    } 
    
    public void mouseClicked(MouseEvent event) { 
        int i = event.getModifiers(); 
        if ((i & 0x10) > 0) 
            this.level += 1; 
        else if (((i & 0xC) > 0) && (this.level > 0)) 
            this.level -= 1; 
        repaint(); 
    } 
        
    public static void main(String[] args) 
    { 
        JFrame mainFrame = new JFrame("Hilbert Demo - Gloomyfish"); 
        mainFrame.getContentPane().setLayout(new BorderLayout()); 
        mainFrame.getContentPane().add(new HilbertUI(), BorderLayout.CENTER); 
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   
        mainFrame.pack();   
        mainFrame.setVisible(true);   
    } 
}