Question

我编写了一个代码来绘制六边形。首先，我使用以下公式绘制6个点：（x + r * cos（i * 2 * pi / 6），y + r * sin（i * 2 * pi / 6））然后在我绘制这些点之后，我尝试使用Bresnham的算法绘制线之间的匹配，我已经在方法中实现了它。不幸的是，代码不能成功运行，我得到的不是六边形。我认为Bresnham的算法实现存在错误。另外，我试图单独绘制每个点，但它不起作用。如果有人可以帮助我？

这也是我的代码：

package javaapplication1;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import java.awt.geom.Line2D;
import static java.lang.Math.cos;
import static java.lang.Math.sin;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;


public class LinesDrawingExample extends JFrame {

    public LinesDrawingExample() {
        super("Lines Drawing Demo");

        //Dimension screenSize=Toolkit.getDefaultToolkit().getScreenSize();

        setSize(500, 500);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
    }

    void drawLines(Graphics g , int x,int y) {
        Graphics2D g2d = (Graphics2D) g;
        g2d.setColor(Color.RED);


        g2d.drawLine(x, y, x,y);


        //g2d.draw(new Line2D.Double(59.2d, 99.8d, 419.1d, 99.8d));

       // g2d.draw(new Line2D.Float(21.50f, 132.50f, 459.50f, 132.50f));

    }

    public void getvalue(Graphics g,double x1,double y1 ,double x2,double y2){









        int x=(int)x1;
        int y=(int)y1;
        int deltax=(int)x2-(int)x1;
        int deltay=(int)y2-(int)y1;
        int twodeltay=2*deltay;
        int var1=twodeltay-(2*deltax);
        int p=twodeltay-deltax;
        drawLines(g,x,y);


        while(x<x2)
        {
            drawLines(g,x,y);

            if(p>0)
            {
            y=y+1;
            p=p+twodeltay-(2*deltax);

            }
            else
            {
                p=p+twodeltay;
            }
            x++;


}
    }

    public void paint(Graphics g) {
        super.paint(g);
        double r=50;
        double pi=3.14;

        int [] xval =new int [6];
        int [] yval=new int [6];

        int x=100,y=100;

       for(int i=0; i<6; i++) {
   getvalue(g,x + r*cos(i*2*pi/6), y + r*sin(i*2*pi/6),x + r*cos(i*2*pi/6),y + r*cos(i*2*pi/6));
   xval[i]=(int)(x + r*cos(i*2*pi/6));
   yval[i]=(int)(y + r*sin(i*2*pi/6));
       }


           getvalue(g,xval[4],yval[4],xval[5],yval[5]);
           getvalue(g,xval[2],yval[2],xval[1],yval[1]);


             getvalue(g,xval[3],yval[3],xval[2],yval[2]);
              getvalue(g,xval[3],yval[3],xval[3],yval[3]);
               getvalue(g,xval[4],yval[4],xval[4],yval[4]);
              getvalue(g,xval[5],yval[5],xval[5],yval[5]);









    }




    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new LinesDrawingExample().setVisible(true);
            }
        });
    }
}

Answer 1

您不应该覆盖paint(g)。改为覆盖paintComponent(g)。您可以使用循环绘制多边形所需的所有点。

绘制点并创建一个Polygon对象，然后绘制多边形对象：

public class DrawPolyPanel extends JPanel{
    public DrawPolyPanel(){
        setPreferredSize(new Dimension(200, 200));
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);            
        Polygon p = new Polygon();
        for (int i = 0; i < 6; i++)
            p.addPoint((int) (100 + 50 * Math.cos(i * 2 * Math.PI / 6)),
              (int) (100 + 50 * Math.sin(i * 2 * Math.PI / 6)));        
        g.drawPolygon(p);    
    }

    public static void main(String[] args){
        JFrame frame = new JFrame("DrawPoly");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new DrawPolyPanel());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

Answer 2

您正在使用JFrame。永远不要在JFrame上绘制。总是在JPanel上画画。

这是GUI。

以下是我所做的主要更改。

我将六边形的创作移动到了自己的类Hexagon中。这样，您可以根据需要创建六边形列表。
我将绘图面板的创建移动到了自己的类DrawingPanel中。这样，我有一个绘制六边形的GUI视图类，以及一个生成六边形的GUI模型类。一个漂亮，干净的关注点分离。
这在LinesDrawingExample类的构造函数中留下了JFrame代码和Hexagon对象的实例化。

这是代码。

package com.ggl.testing;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Polygon;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class LinesDrawingExample extends JFrame {

    private static final long serialVersionUID = 3775690273871048733L;

    private DrawingPanel drawingPanel;

    public LinesDrawingExample() {
        super("Lines Drawing Demo");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Hexagon hexagon = new Hexagon(new Point(250, 250), 200);

        drawingPanel = new DrawingPanel(hexagon);
        add(drawingPanel);

        pack();
        setLocationByPlatform(true);
        setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new LinesDrawingExample();
            }
        });
    }

    public class DrawingPanel extends JPanel {
        private static final long serialVersionUID = 5701311351092275287L;

        private Hexagon hexagon;

        public DrawingPanel(Hexagon hexagon) {
            this.hexagon = hexagon;
            this.setPreferredSize(new Dimension(500, 500));
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);

            g.setColor(Color.RED);
            g.drawPolygon(hexagon.getHexagon());
        }
    }

    public class Hexagon {
        private final int radius;

        private final Point center;

        private final Polygon hexagon;

        public Hexagon(Point center, int radius) {
            this.center = center;
            this.radius = radius;
            this.hexagon = createHexagon();
        }

        private Polygon createHexagon() {
            Polygon polygon = new Polygon();

            for (int i = 0; i < 6; i++) {
                int xval = (int) (center.x + radius
                        * Math.cos(i * 2 * Math.PI / 6D));
                int yval = (int) (center.y + radius
                        * Math.sin(i * 2 * Math.PI / 6D));
                polygon.addPoint(xval, yval);
            }

            return polygon;
        }

        public int getRadius() {
            return radius;
        }

        public Point getCenter() {
            return center;
        }

        public Polygon getHexagon() {
            return hexagon;
        }

    }
}

使用Java错误绘制六角形

2 个答案: