如何用Matplotlib绘制目标图形？使用Grid实现时遇颜色填充与坐标轴问题求助

Hey there! Let's work through those Matplotlib Grid hurdles you're hitting with color filling and axis configuration—nice move referencing the official docs already, that’s such a solid starting point. Even with a trimmed-down reference image, we can break this down into actionable fixes.

Color Filling Fixes #

• Block-by-Block Coloring: If you need to fill specific grid cells with custom colors, using matplotlib.patches.Rectangle lets you draw individual colored blocks and snap them to grid lines. For larger grids though, imshow paired with a color matrix is way more efficient: create a 2D array where each value maps to a cell’s color, then use imshow with extent to align it to your axis bounds.
• Alignment Tweaks: If your fills aren’t lining up with grid lines, check the origin parameter (set origin='lower' to match standard axis direction) and adjust xlim/ylim to lock the axis range exactly to your grid dimensions.

Axis Setup Adjustments #

• Grid-Aligned Ticks: To make ticks match your grid lines, use plt.xticks() and plt.yticks() with explicit positions. For example, a 6x6 grid would use plt.xticks(np.arange(0, 7, 1)) to place ticks at every grid edge.
• Custom Bounds: If your reference image has a specific axis range, override the default with plt.xlim(min_x, max_x) and plt.ylim(min_y, max_y)—this ensures your trimmed grid matches the reference’s scale.
• Clean Up Clutter: Hide unnecessary axis spines or ticks with ax.spines[['top', 'right']].set_visible(False) or ax.tick_params(axis='both', which='both', top=False, right=False) for a cleaner look that matches your target.

Quick Example Code #

Here’s a minimal snippet to tie this together:

import matplotlib.pyplot as plt
import numpy as np

# Define grid dimensions
grid_rows, grid_cols = 5, 5

# Create a color matrix (customize values for your target colors)
color_grid = np.zeros((grid_rows, grid_cols))
color_grid[1:3, 2:4] = 0.7  # Fill a 2x2 block with a specific shade
color_grid[0, :] = 0.3       # Fill the top row

fig, ax = plt.subplots()

# Plot colored grid with imshow
im = ax.imshow(color_grid, cmap='coolwarm', origin='lower', 
               extent=[0, grid_cols, 0, grid_rows])

# Add grid lines that align with cell edges
ax.set_xticks(np.arange(0, grid_cols + 1, 1))
ax.set_yticks(np.arange(0, grid_rows + 1, 1))
ax.grid(which='both', color='black', linewidth=1.5)

# Set axis labels and adjust bounds
ax.set_xlabel('Custom X Axis')
ax.set_ylabel('Custom Y Axis')
ax.set_xlim(0, grid_cols)
ax.set_ylim(0, grid_rows)

# Optional: Add color bar for reference
fig.colorbar(im)

plt.show()

If your target has more complex color rules (like categorical colors) or unique axis formatting, sharing a bit more detail about those specifics would help refine this further!

内容的提问来源于stack exchange，提问作者SiriusHsh