Question

我想在Java中创建一个简单的网格，作为使用tile的地图编辑器。在我的渲染方法中，我把这个

public void render(Graphics g){
    renderGrid(g,96,64);

}

private void renderGrid(Graphics g,int width, int height) {
    g.setColor(Color.white);
    for (int y = 0; y < height; y += 32){
        for (int x = 0;x<width; x+= 32){
                g.drawRect(x, y, x+32, y+32);
                System.out.println("x =" + x + " y= " + y + " width= " + (x + 32 - x) + " height=" + (y + 32 - y)+ " column No= " + x/32 + " row No= " + y / 32);
        }
    }
}

但是当我启动程序时，它给了我这个：

error

这是调试消息

x =0 y= 0 width= 32 height=32 column No= 0 row No= 0
x =32 y= 0 width= 32 height=32 column No= 1 row No= 0
x =64 y= 0 width= 32 height=32 column No= 2 row No= 0
x =0 y= 32 width= 32 height=32 column No= 0 row No= 1
x =32 y= 32 width= 32 height=32 column No= 1 row No= 1
x =64 y= 32 width= 32 height=32 column No= 2 row No= 1

有什么建议吗？为什么细胞不是正方形？

Answer 1

您的问题是drawRect takes起始位置和尺寸，而不是起始位置和结束位置。所以它应该是： -

//drawRect(int x, int y, int width, int height)
g.drawRect(x, y, 32, 32);

<强>另外

此(x + 32 - x)和此(y + 32 - y)与(32)

相同

Answer 2

问题就在这里：

g.drawRect(x, y, x+32, y+32);

应该是：

g.drawRect(x, y, 32, 32);

第3和第4个参数是宽度和高度，而不是“绘制到那个点”。可见：

enter image description here

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

class GridCells {

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                JOptionPane.showMessageDialog(null, new GridCellPanel());
            }
        };
        // Swing GUIs should be created and updated on the EDT
        // http://docs.oracle.com/javase/tutorial/uiswing/concurrency
        SwingUtilities.invokeLater(r);
    }
}

class GridCellPanel extends JPanel {

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        setBackground(Color.BLACK);
        render(g);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 100);
    }

    public void render(Graphics g) {
        renderGrid(g, 96, 64);
    }

    private void renderGrid(Graphics g, int width, int height) {
        g.setColor(Color.white);
        for (int y = 0; y < height; y += 32) {
            for (int x = 0; x < width; x += 32) {
                g.drawRect(x, y, 32, 32);
                System.out.println("x =" + x + " y= " + y + " width= " + 
                        (x + 32 - x) + " height=" + (y + 32 - y) + 
                        " column No= " + x / 32 + " row No= " + y / 32);
            }
        }
    }
}

Answer 3

接受答案后我不确定你是否想要填写整个scrren，所以在我看到接受的答案之前，我正在研究这个问题。我会保留它以防万一你正在寻找

不完全确定您的代码逻辑，但我提出了自己的逻辑，似乎更容易理解。

获取绘图表面的宽度

private static final int SCREEN_SIZE = 300;

为每个sqaure设置所需的尺寸。

private static final int G_W = 30;
private static final int G_H = 30;

通过将SCREEN_SIZE除以方形宽度/高度来获取行数和列数
```
int columns = SCREEN_WIDTH / G_W;
int rows = SCREEN_WIDTH / G_H;
```

执行上述操作后，循环更容易管理

for (int i = 0; i < rows; i++) {
    for (int j = 0; j < columns; j++) {
        g.drawRect(x, y, G_W, G_H);
        x += G_W;
    }
    y += G_H;
    x = 0;
}

完整代码

import java.awt.Dimension;
import java.awt.Graphics;

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


public class Grid extends JPanel{

    private static final int SCREEN_SIZE = 300;
    private static final int G_W = 30;
    private static final int G_H = 30;

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

        int x = 0;
        int y = 0;

        int columns = SCREEN_SIZE / G_W;
        int rows = SCREEN_SIZE / G_W;

        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < columns; j++) {
                g.drawRect(x, y, G_W, G_H);
                x += G_W;
            }
            y += G_H;
            x = 0;
        }

    }

    public Dimension getPreferredSize() {
        return new Dimension(SCREEN_SIZE, SCREEN_SIZE);

    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new Grid());
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

            }
        });
    }
}

结果

enter image description here

绘制网格问题

3 个答案: