python 生成六宫格的数独题并画出相应的方格导出到pdf

生成数独题可以使用回溯算法，画出相应的方格可以使用Python的`reportlab`库来创建PDF文件并添加矩形和文本。下面是一个简单的实现示例：

from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import cm, mm
from reportlab.lib import colors

import random

# 生成数独题
def generate_sudoku():
    board = [[0 for _ in range(9)] for _ in range(9)]
    rows = [set(range(1, 10)) for _ in range(9)]
    cols = [set(range(1, 10)) for _ in range(9)]
    boxes = [set(range(1, 10)) for _ in range(9)]
    empty_cells = []

    # 随机填充一个数独的第一行
    nums = random.sample(range(1, 10), 9)
    for i in range(9):
        board[0][i] = nums[i]
        rows[0].remove(nums[i])
        cols[i].remove(nums[i])
        boxes[(i // 3) * 3 + (i % 3)].remove(nums[i])

    # 回溯填充数独
    def backtrack(idx):
        nonlocal empty_cells
        if idx == len(empty_cells):
            return True
        i, j = empty_cells[idx]
        box_idx = (i // 3) * 3 + (j // 3)
        candidates = rows[i] & cols[j] & boxes[box_idx]
        for num in candidates:
            board[i][j] = num
            rows[i].remove(num)
            cols[j].remove(num)
            boxes[box_idx].remove(num)
            if backtrack(idx + 1):
                return True
            rows[i].add(num)
            cols[j].add(num)
            boxes[box_idx].add(num)
        return False

    # 随机挖空
    for i in range(9):
        for j in range(9):
            if random.random() < 0.5:
                empty_cells.append((i, j))
    random.shuffle(empty_cells)
    if not backtrack(0):
        raise ValueError('Unable to generate sudoku')

    return board

# 画出数独方格
def draw_sudoku_grid(canvas_obj, x, y, size, board):
    cell_size = size / 9
    canvas_obj.setStrokeColor(colors.black)
    canvas_obj.setLineWidth(1)

    # 画出单元格边框
    for i in range(10):
        offset = i * cell_size
        if i % 3 == 0:
            canvas_obj.setLineWidth(2)
        else:
            canvas_obj.setLineWidth(1)
        canvas_obj.line(x, y + offset, x + size, y + offset)
        canvas_obj.line(x + offset, y, x + offset, y + size)

    # 填入数字
    canvas_obj.setFontSize(int(cell_size * 0.6))
    canvas_obj.setFillColor(colors.black)
    for i in range(9):
        for j in range(9):
            if board[i][j] != 0:
                canvas_obj.drawString(x + j * cell_size + cell_size * 0.35,
                                       y + (8 - i) * cell_size + cell_size * 0.3,
                                       str(board[i][j]))

# 生成pdf文件
def generate_pdf(board, filename):
    canvas_obj = canvas.Canvas(filename, pagesize=A4)
    canvas_obj.setTitle('Sudoku Puzzle')

    # 设置字体
    from reportlab.pdfbase.ttfonts import TTFont
    from reportlab.pdfbase import pdfmetrics
    pdfmetrics.registerFont(TTFont('Arial', 'Arial.ttf'))

    # 添加标题和日期
    canvas_obj.setFont('Arial', 24)
    canvas_obj.drawCentredString(A4[0] / 2, A4[1] - 2 * cm, 'Sudoku Puzzle')
    canvas_obj.setFont('Arial', 16)
    canvas_obj.drawCentredString(A4[0] / 2, A4[1] - 3 * cm, 'Generated on 2021-10-10')

    # 画出数独方格
    draw_sudoku_grid(canvas_obj, 2 * cm, 2 * cm, A4[0] - 4 * cm, board)

    # 保存pdf文件
    canvas_obj.save()

# 生成数独题并导出为pdf文件
board = generate_sudoku()
generate_pdf(board, 'sudoku.pdf')
print('PDF file generated successfully.')

这个示例会在当前目录下生成一个名为`sudoku.pdf`的文件，其中包含生成的数独题。你可以根据需要调整字体大小、颜色和布局等参数。