alg.java

用JAVA写的画图软件

package graphInterface;

import java.awt.*;
import java.util.Stack;
import javax.swing.JPanel;

public class Alg {
	private static int abs(int n) {
		return Math.abs(n);
	}

	public static void line(Graphics g, int x0, int y0, int xt, int yt) {
		// bresonham 画线法
		if (x0 > xt) {
			int temp = x0;
			x0 = xt;
			xt = temp;
			temp = y0;
			y0 = yt;
			yt = temp;
		}
		
		int dy = yt > y0 ? yt - y0 : y0 - yt;
		int ystep = yt > y0 ? 1 : -1;
		int dx = xt - x0;
		
		if (dy < dx) {
			int e = -dx;
			int x = x0;
			int y = y0;
		
			for (int i=0; i<=dx; ++i) {
				g.drawLine(x, y, x, y);
				++x;
				e = e + dy * 2;
				if (e >= 0) {
					y += ystep;
					e = e - dx * 2;
				}
			}
		}
		else {
			int e = -dy;
			int x = x0;
			int y = y0;
			
			for (int i=0; i<=dy; ++i) {
				g.drawLine(x, y, x, y);
				y += ystep;
				e = e + dx * 2;
				if (e >= 0) {
					++x;
					e = e - dy * 2;
				}
			}
		}
	}

	public static void round(Graphics g, int x0, int y0, int r) {
		// 画圆算法，先用系统画圆替代
		g.drawArc(x0 - r, y0 - r, r + r, r + r, 0, 360);
	}
	
	public static void eclipse(Graphics g, int x0, int y0, int a, int b) {
		g.drawArc(x0 - a, y0 - b, a + a, b + b, 0, 360);
	}
	public static void fill(Graphics g, JPanel panel, Color bg, int x, int y) {
		Stack s = new Stack();
		s.push(new Point(x, y));
		while (!s.empty()) {
			Point p = (Point)s.pop();
			//panel.getBackground()
			
		}
	}
}