Python图案特定区域着色：填充方块间隙为黄色并输出坐标

我用Python生成包含方块的网格图案，已完成红色（水平间隙）和绿色（垂直间隙）的填充，现在需要把方块之间交叉的空白区域填充为黄色，并输出这些黄色方块的坐标。以下是我的实现代码和当前效果：

import matplotlib.pyplot as plt

# Define the grid size and the number of squares
grid_size = 4
square_size = 1  # Size of each square
gap = 0.1        # Gap between squares

# Create a new figure
plt.figure(figsize=(6, 6), dpi=80)

# Lists to store the coordinates of the rectangles
green_rectangles = []
red_rectangles = []

# Add yellow rectangles to fill the gaps before drawing the squares
for row in range(grid_size):
    for col in range(grid_size):
        # Calculate the coordinates for the bottom-left corner of the gap
        x = col * (square_size + gap)
        y = row * (square_size + gap)
        
        # Create a yellow rectangle for the gap
        if row < grid_size - 1:
            plt.Rectangle((x, y + square_size), square_size, gap, edgecolor='none', facecolor='yellow')
        if col < grid_size - 1:
            plt.Rectangle((x + square_size, y), gap, square_size + gap, edgecolor='none', facecolor='yellow')

# Loop through rows and columns to draw the squares
for row in range(grid_size):
    for col in range(grid_size):
        # Calculate the coordinates for the bottom-left corner of the square
        x = col * (square_size + gap)
        y = row * (square_size + gap)
        
        # Create a square using plt.Rectangle
        rectangle = plt.Rectangle((x, y), square_size, square_size, edgecolor='black', facecolor='black')
        plt.gca().add_patch(rectangle)

# Add green rectangles to fill the vertical gaps
for row in range(grid_size):
    for col in range(grid_size - 1):  # Exclude the last column
        x = (col + 1) * (square_size + gap) - gap
        y = row * (square_size + gap)
        green_rectangle = plt.Rectangle((x, y), gap, square_size, edgecolor='none', facecolor='green')
        plt.gca().add_patch(green_rectangle)
        green_rectangles.append((x, y))

# Add red rectangles to fill the horizontal gaps
for row in range(grid_size - 1):  # Exclude the last row
    for col in range(grid_size):
        x = col * (square_size + gap)
        y = (row + 1) * (square_size + gap) - gap
        red_rectangle = plt.Rectangle((x, y), square_size, gap, edgecolor='none', facecolor='red')
        plt.gca().add_patch(red_rectangle)
        red_rectangles.append((x, y))

# Print the coordinates of the red and green rectangles
print("Green rectangles:")
for coord in green_rectangles:
    print(coord)

print("\nRed rectangles:")
for coord in red_rectangles:
    print(coord)

# Set the aspect of the plot to be equal, so squares appear as squares
plt.gca().set_aspect('equal')

# Set limits to accommodate the gaps
plt.xlim(0, grid_size * (square_size + gap))
plt.ylim(0, grid_size * (square_size + gap))

# Remove axis values
plt.gca().set_xticks([])
plt.gca().set_yticks([])

# Add grid lines for better visualization
plt.grid(True, which='both', linestyle='--', linewidth=0.5)

# Show the plot
plt.show()

当前效果：

原代码中黄色方块未显示的核心问题是未将创建的矩形添加到画布，同时位置和尺寸计算错误。以下是修正后的完整代码：

import matplotlib.pyplot as plt

# Define the grid size and the number of squares
grid_size = 4
square_size = 1  # Size of each square
gap = 0.1        # Gap between squares

# Create a new figure
plt.figure(figsize=(6, 6), dpi=80)

# Lists to store the coordinates of the rectangles
green_rectangles = []
red_rectangles = []
yellow_rectangles = []  # 新增存储黄色方块坐标的列表

# 先绘制黄色交叉间隙（方块之间的空白区域）
for row in range(grid_size - 1):
    for col in range(grid_size - 1):
        # 计算黄色方块的左下角坐标：水平间隙和垂直间隙的交叉点
        x = (col + 1) * (square_size + gap) - gap
        y = (row + 1) * (square_size + gap) - gap
        # 创建gap×gap的黄色正方形
        yellow_rect = plt.Rectangle((x, y), gap, gap, edgecolor='none', facecolor='yellow')
        plt.gca().add_patch(yellow_rect)
        yellow_rectangles.append((x, y))

# Loop through rows and columns to draw the squares
for row in range(grid_size):
    for col in range(grid_size):
        # Calculate the coordinates for the bottom-left corner of the square
        x = col * (square_size + gap)
        y = row * (square_size + gap)
        
        # Create a square using plt.Rectangle
        rectangle = plt.Rectangle((x, y), square_size, square_size, edgecolor='black', facecolor='black')
        plt.gca().add_patch(rectangle)

# Add green rectangles to fill the vertical gaps
for row in range(grid_size):
    for col in range(grid_size - 1):  # Exclude the last column
        x = (col + 1) * (square_size + gap) - gap
        y = row * (square_size + gap)
        green_rectangle = plt.Rectangle((x, y), gap, square_size, edgecolor='none', facecolor='green')
        plt.gca().add_patch(green_rectangle)
        green_rectangles.append((x, y))

# Add red rectangles to fill the horizontal gaps
for row in range(grid_size - 1):  # Exclude the last row
    for col in range(grid_size):
        x = col * (square_size + gap)
        y = (row + 1) * (square_size + gap) - gap
        red_rectangle = plt.Rectangle((x, y), square_size, gap, edgecolor='none', facecolor='red')
        plt.gca().add_patch(red_rectangle)
        red_rectangles.append((x, y))

# Print the coordinates of all colored rectangles
print("Green rectangles:")
for coord in green_rectangles:
    print(coord)

print("\nRed rectangles:")
for coord in red_rectangles:
    print(coord)

print("\nYellow rectangles:")
for coord in yellow_rectangles:
    print(coord)

# Set the aspect of the plot to be equal, so squares appear as squares
plt.gca().set_aspect('equal')

# Set limits to accommodate the gaps
plt.xlim(0, grid_size * (square_size + gap))
plt.ylim(0, grid_size * (square_size + gap))

# Remove axis values
plt.gca().set_xticks([])
plt.gca().set_yticks([])

# Add grid lines for better visualization
plt.grid(True, which='both', linestyle='--', linewidth=0.5)

# Show the plot
plt.show()

关键改动说明 #

1. 新增yellow_rectangles列表：专门存储黄色方块的左下角坐标，用于后续输出
2. 修正黄色方块的绘制逻辑：
   • 只遍历grid_size-1行和列，对应方块之间的交叉空白区域
   • 坐标计算为水平间隙和垂直间隙的交叉点，尺寸为gap×gap的正方形
   • 调用add_patch()将黄色矩形添加到画布，确保显示
3. 补充黄色坐标输出：在控制台打印黄色方块的坐标

内容的提问来源于stack exchange，提问作者user23495528