Python 3.x 栅格打印：不完整/截断栅格

我是Python新手，我正在尝试创建网格打印颜色贴图。生成的绘图在底行和顶行上具有不完整的网格（被截断，因此它们不是正方形）。我该怎么补救呢？非常感谢您的编辑/建议

precursor = ["PMe3", "PPh3", "Pyridine", "DME"]
powder = ["NiCl2", "RhCl3", "NiBr2", "NiI2"]

mp = np.array([[194, 230, 145, 165], [247, 270, 222, 218], [319, 285, 0, 0], [300, 0, 0, 0]])

fig, ax = plt.subplots()
im = ax.imshow(mp)

ax.set_xticks(np.arange(len(powder)))
ax.set_yticks(np.arange(len(precursor)))

ax.set_xticklabels(powder)
ax.set_yticklabels(precursor)

plt.setp(ax.get_xticklabels(), rotation=45, rotation_mode="anchor")

for i in range(len(precursor)):
    for j in range(len(powder)):
        text = ax.text(j, i, mp[i, j], ha="center", va="center", color="w")

ax.set_title("MP of MLX Complex")
fig.tight_layout()

plt.show()