Question

我正在尝试在bufferedimage上绘制水平和垂直线条。它应该看起来像一个细胞网格。但是当我运行代码时，我只看到两行：最左边的行和最上面的行（即从0,0到0的行，图像的高度和0,0到图像的宽度，0）继承代码片段：

  BufferedImage mazeImage = new BufferedImage(imgDim.width, imgDim.height, BufferedImage.TYPE_INT_RGB);
  Graphics2D g2d = mazeImage.createGraphics();
  g2d.setBackground(Color.WHITE);
  g2d.fillRect(0, 0, imgDim.width, imgDim.height);
  g2d.setColor(Color.BLACK);
  BasicStroke bs = new BasicStroke(2);
  g2d.setStroke(bs);
  // draw the black vertical and horizontal lines
  for(int i=0;i<21;i++){
   g2d.drawLine((imgDim.width+2)*i, 0, (imgDim.width+2)*i,  imgDim.height-1);
   g2d.drawLine(0, (imgDim.height+2)*i, imgDim.width-1, (imgDim.height+2)*i);
  }

覆盖绘画方法：

public void paint(Graphics g) {
  g.drawImage(mazeImage, 0, 0, this);
}

这是一个名为RobotMaze的类，它扩展了JPanel。任何帮助表示赞赏。

Answer 1

import java.awt.*;
import java.awt.image.*;
import javax.swing.*;

class GridLines {

    public static void main(String[] args) {

        Dimension imgDim = new Dimension(200,200);
        BufferedImage mazeImage = new BufferedImage(imgDim.width, imgDim.height, BufferedImage.TYPE_INT_RGB);


        Graphics2D g2d = mazeImage.createGraphics();
        g2d.setBackground(Color.WHITE);
        g2d.fillRect(0, 0, imgDim.width, imgDim.height);
        g2d.setColor(Color.BLACK);
        BasicStroke bs = new BasicStroke(2);
        g2d.setStroke(bs);
        // draw the black vertical and horizontal lines
        for(int i=0;i<21;i++){
            // unless divided by some factor, these lines were being
            // drawn outside the bound of the image..
            g2d.drawLine((imgDim.width+2)/20*i, 0, (imgDim.width+2)/20*i,imgDim.height-1);
            g2d.drawLine(0, (imgDim.height+2)/20*i, imgDim.width-1, (imgDim.height+2)/20*i);
        }

        ImageIcon ii = new ImageIcon(mazeImage);
        JOptionPane.showMessageDialog(null, ii);
    }
}

Answer 2

打印出你的坐标，你会发现你正在绘制超出图像宽度和高度的点：

System.out.printf("Vertical: (%d,%d)->(%d,%d)\n",(imgDim.width+2)*i, 0, (imgDim.width+2)*i,  imgDim.height-1);
System.out.printf("Horizontal: (%d,%d)->(%d,%d)\n",0, (imgDim.height+2)*i, imgDim.width-1, (imgDim.height+2)*i);

Answer 3

如果我＆gt;你如何期望(imgDim.width+2)*i的结果在图像边界内？ 0？

在BufferedImage中绘制多条线

3 个答案: