在BufferedImage中绘制多条线

我试图在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）下面是代码片段：

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); } 

和覆盖绘画方法：

 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图像宽度和高度之外的点：

 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i> 0，您如何期望(imgDim.width+2)*i的结果在图像边界内？