java - 在JPanel中画一个迷宫

Question

我正在用 Java 制作一个随机迷宫生成器。用户可以选择算法，然后按“生成”按钮以在 JFrame 中心查看生成的迷宫。迷宫生成后，我必须将其绘制在 JPanel 内。如果我们考虑使用回溯算法的 dfs，对于每个单元格，我有 4 个 boolean 变量，指示该单元格是否有向上、向下、向左、向右的墙。该算法运行并相应地移除这些墙(梦剧场\m/)。现在每个单元格都应该具有绘制迷宫所需的信息，但我不知道该怎么做。我无法使用索引来绘制线条。

这是代码草案:

BufferedImage image = new BufferedImage(MAZE_PANEL_DIM, MAZE_PANEL_DIM,BufferedImage.TYPE_INT_RGB);
Graphics g2 = image.getGraphics();
g2.setColor(Color.WHITE);
g2.fillRect(0, 0, MAZE_PANEL_DIM, MAZE_PANEL_DIM);
g2.setColor(Color.BLACK);
for(int i = 0; i < Maze.DIM; i++) {          
    for(int j = 0; j < Maze.DIM; j++) {      // Note: the size of the cell is CELL_DIM = 600 / Maze.DIM
        Cell cell = cells[i][j];
        if(cell.hasRightWall()) {
            // draw vertical line on the right border of the cell
        }
        if(cell.hasDownWall()) {
            // draw horizontal line on the bottom border of the cell
        }
        if(cell.hasLeftWall()) {
            // draw vertical line on the left border of the cell
        }
        if(cell.hasUpWall()) {
            // draw horizontal line on the top border of the cell
        }
    }
}

更新

好吧，解决方案应该是这样的......

for(int i = 0; i < Maze.DIM; i++) {          
    for(int j = 0; j < Maze.DIM; j++) {      // Note: the size of the cell is CELL_DIM = 600 / Maze.DIM
        Cell cell = cells[i][j];
        if(cell.hasRightWall()) {
            // draw vertical line on the right border of the cell
            g2.drawLine(j * CELL_DIM + CELL_DIM, i * CELL_DIM, CELL_DIM + j * CELL_DIM, CELL_DIM + i * CELL_DIM);
        }
        if(cell.hasDownWall()) {
            // draw horizontal line on the bottom border of the cell
            g2.drawLine(j * CELL_DIM, i * CELL_DIM + CELL_DIM, j * CELL_DIM + CELL_DIM, i * CELL_DIM + CELL_DIM);
        }
        if(cell.hasLeftWall()) {
            // draw vertical line on the left border of the cell
            g2.drawLine(j * CELL_DIM, i * CELL_DIM, j * CELL_DIM, CELL_DIM + i * CELL_DIM);
        }
        if(cell.hasUpWall()) {
            // draw horizontal line on the top border of the cell
            g2.drawLine(j * CELL_DIM, i * CELL_DIM , CELL_DIM + j * CELL_DIM, i * CELL_DIM);
        }
    }
}

问题是右边框和下边框没有被绘制。

Answer 1

docs对于 Graphics 类来说:

The graphics pen hangs down and to the right from the path it traverses.

因此，如果您尝试在迷宫的右侧边缘绘制单元格的右侧边框，Graphics 笔将位于您的 BufferedImage 之外>。解决方案是对线段的坐标进行边界检查，并确保所有线条都绘制在图像内。

if (cell.hasRightWall()) {
  int fromX = j * CELL_DIM + CELL_DIM;
  int fromY = i * CELL_DIM;

  if (fromX >= image.getWidth()) {
    fromX = image.getWidth() - 1;
  }

  g2.drawLine(fromX, fromY, fromX, fromY + CELL_DIM);
}