Question

我编写了一个代码，用于在一个网格单元格内绘制网格和三角形。当窗口最大化或最小化时，网格大小增加/减少。

我的要求是，每当网格大小增加/减少时，三角形大小也应增加/减小以适合网格单元格。

我的代码如下：

import java.awt.BasicStroke;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.RenderingHints;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;


public class Grid extends JPanel {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Grid g = new Grid();
        JFrame f = new JFrame("Application GUI Window");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        f.getContentPane().add("Center", g);
        f.pack();
        f.setSize(new Dimension(450,400));
        f.show();
    }

    public void paint(Graphics g) {

        Graphics2D g2d = (Graphics2D) g;
        Dimension d = getSize();
        g2d.setBackground(getBackground());
        g2d.clearRect(0, 0, d.width, d.height);
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        drawGrid(d.width, d.height, g2d);
        int[] xPoints = {20,15,25}; 
        int[] yPoints = {15,25,25};
        int n = 3;

        Polygon triangle = new Polygon(xPoints, yPoints, n);
        g.fillPolygon(triangle);
    }

    private void drawGrid(int width, int height, Graphics2D g2d) {

       /* BasicStroke border = new BasicStroke(3, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND, 0, new float[]{0,1,0,1}, 0);
        g2d.setStroke(border);
        g2d.drawRect(3,3,width-6,height-6);*/

        //horizontal lines
        int cellheight = height/10;
        int cellwidth = width/5;
        for (int j=0;j<height;j=j+cellheight)
        {
            BasicStroke line = new BasicStroke(1, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND, 0, new float[]{0,1,0,1}, 0);
               g2d.setStroke(line);
               g2d.drawLine(0, j, cellwidth*5, j);

        }

        //vertical lines

        for (int i=0;i<width;i=i+cellwidth)
        {
            BasicStroke line = new BasicStroke(1, BasicStroke.CAP_SQUARE, BasicStroke.JOIN_ROUND, 0, new float[]{0,1,0,1}, 0);
               g2d.setStroke(line);
               g2d.drawLine(i, 0, i, cellheight*10);

        }

    }
}

提前感谢您的帮助。

Answer 1

您可以将三角形的坐标与网格单元的尺寸联系起来。以下是基于您的示例的代码段：

int cellHeight = d.height/10;
int cellWidth = d.width/5;

int xOffset = cellWidth/6;
int yOffset = cellHeight/6;

int[] xPoints = {cellWidth/2, xOffset, cellWidth - xOffset}; 
int[] yPoints = {yOffset, cellHeight - yOffset, cellHeight - yOffset};

Polygon triangle = new Polygon(xPoints, yPoints, xPoints.length);

请注意，在Swing中，除非在某些特殊情况下，否则通常应覆盖paintComponent()而不是paint()。有关详细信息，请参阅A Closer Look at the Paint Mechanism。

另请注意，show()已弃用，而不是setVisible()。您可以将其替换为：setVisible(true)

矩形网格内的三角形

1 个答案: