circle.java

ErGo是一个很早的Java通用围棋服务器(IGS/NNGS)客户端程序。有全部源码和文档

package ergo.ui;

// $Id: Circle.java,v 1.4 1999/08/15 01:40:28 sigue Exp $

/*
 *  Copyright (C) 1999  Carl L. Gay and Antranig M. Basman.
 *  See the file copyright.txt, distributed with this software,
 *  for further information.
 */

/**
 * Bresenham circle drawing.
 */
public class Circle {
  CircleOdd odd = new CircleOdd();
  CircleEven even = new CircleEven();
  public void emptycirc (RawImage imag1, int color, int diameter) {  
    if (diameter % 2 == 1) {
      odd.emptycirc(imag1, color, diameter);
    }
    else {
      even.emptycirc(imag1, color, diameter);
    }
  }
  public void fillcirc (RawImage imag1, int color, int diameter) {  
    if (diameter % 2 == 1) {
      odd.fillcirc(imag1, color, diameter);
    }
    else {
      even.fillcirc(imag1, color, diameter);
    }
  }
}
      
/**
 * Deals with odd-sized extents(bitmaps).
 */
class CircleOdd {
  private int d, x, y, r;
  private int r2p1;
  private int xorig, yorig;
  private int cellSize, cellSize2;
  private RawImage imag;

  public void init (RawImage imag1) {
    imag = imag1;
    cellSize = imag.width;
    cellSize2 = cellSize / 2;
    xorig = yorig = cellSize2;
    imag.setorig(xorig, yorig);
  }

  private void brezinit (int diameter) {
    r = diameter / 2;
    r2p1 = diameter;
    d = 5 - diameter;
    x = 0;
    y = -r - 1;
  }

  private boolean breznext () {
    if (r2p1 == 1)
      return false;
    boolean plipy = false;
    if (d >= 0) {
      d = d + 4 * (x + y) + 14;
      ++y;
      plipy = true;
    }
    else
      d = d + 4 * x + 8;
    ++x;
    if ((x + y) > -1)
      return false;
    if ((x + y) == -1 && !plipy)
      return false;
    return true;
  }

  private void setband (int color, int x1, int y1) {
    imag.setband(color, -x1-1, x1, y1);
  }

  public void emptycirc (RawImage imag1, int color, int diameter) {
    init(imag1);
    brezinit(diameter);
    do {
      imag.setpixel(color, x, y);  imag.setpixel(color, y, x);
      imag.setpixel(color, -x - 1, y);  imag.setpixel(color, y, -x - 1);
      imag.setpixel(color, x, -y - 1);  imag.setpixel(color, -y - 1, x);
      imag.setpixel(color, -x - 1, -y - 1);  imag.setpixel(color, -y - 1, -x - 1);
    } while (breznext());
  }
  public void fillcirc (RawImage imag1, int color, int diameter) {
    init(imag1);
    brezinit(diameter);
    //    setband(color, radius, 0);
    int lasty = y;
    int lastx = x;
    // 1st time round is for free.
    do {
      // now, circle is drawn from position (0, -r); so up to band, we
      // pass rotated 90o anticlockwise.... this draws 'fat half' of circle
      setband(color, -y - 1, x);
      setband(color, -y - 1, -x - 1); 
      if (y != lasty) {		// if we took an upward step, draw the top and bottom
        // slivers, too, as the last 'jutty out' bit we got up to....
        setband(color, lastx, lasty);
        setband(color, lastx, -lasty - 1);
      }
      lastx = x;
      lasty = y;
    } while (breznext());	// end breznext
    setband(color, lastx, lasty); // Since breznext does not give us "symmetric" pixel,
    setband(color, lastx, -lasty - 1); // Explicitly draw line before it.
  }
}  // end class circleOdd


/**
 * Deals with even-sized extents(bitmaps).
 */
class CircleEven {
  private int d, x, y, r;
  private int xorig, yorig;
  private int cellSize, cellSize2;
  private RawImage imag;

  public void init(RawImage imag1) {
    imag = imag1;
    cellSize = imag.width;
    cellSize2 = cellSize / 2;
    xorig = yorig = cellSize2;
    imag.setorig(xorig, yorig);
  }

  private void brezinit (int diameter) {
    r = diameter / 2;
    d = 5 - 4 * r;
    x = 0;
    y = -r;
  }

  private boolean breznext () {
    boolean plipy = false;

    if (d >= 0) {
      d = d + 8 * (x + y) + 20;
      ++y;
      plipy = true;
    }
    else
      d = d + 8 * x + 12;
    ++x;
    if ((x + y) > 0)
      return false;
    if ((x + y) == 0 && !plipy)
      return false;
    return true;
  }

  private void setband (int color, int x1, int y1) {
    imag.setband(color, -x1, x1, y1);
  }

  public void emptycirc (RawImage imag1, int color, int diameter) {
    init(imag1);
    brezinit(diameter);
    imag.setpixel(color, 0, -r);  
    imag.setpixel(color, 0, r);
    imag.setpixel(color, -r, 0);  imag.setpixel(color, r, 0);
    while (breznext()) {
      imag.setpixel(color, x, y);  imag.setpixel(color, y, x);
      imag.setpixel(color, -x, y);  imag.setpixel(color, y, -x);
      imag.setpixel(color, x, -y);  imag.setpixel(color, -y, x);
      imag.setpixel(color, -x, -y);  imag.setpixel(color, -y, -x);
    }
  }

  public void fillcirc (RawImage imag1, int color, int diameter) {
    init(imag1);
    brezinit(diameter);
    setband(color, r, 0);	// Draw single 0th band
    int lasty = y;
    int lastx = x;
    while (breznext()) {
      // now, circle is drawn from position (0, -r); so up to band, we
      // pass rotated 90o anticlockwise.... this draws 'fat half' of circle
      setband(color, -y, x);
      setband(color, -y, -x); 
      if (y != lasty) {		// if we took an upward step, draw the top and bottom
	// slivers, too, as the last 'jutty out' bit we got up to....
	setband(color, lastx, lasty);
	setband(color, lastx, -lasty);
      }
      lastx = x;
      lasty = y;
    }				// end breznext
    setband(color, lastx, lasty); // Since breznext does not give us "symmetric" pixel,
    setband(color, lastx, -lasty); // Explicitly draw line before it.
  }
}  // end class CircleEven