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<p>我正在用Matplotlib设计一个三维插图。所有的工作都很顺利,除了(红色)参数曲线得到错误的zorder而(绿色)参数化曲面绘制完全正确。在</p>
<p>由以下代码生成的输出:
<img src="https://i.stack.imgur.com/78oDL.png" alt="Output generated by code below"/></p>
<p>我知道Matplotlib在精确计算对象的zorder方面能力有限,但是由于它可以对参数化曲面执行此操作,所以它似乎是Matplotlib中的一个bug。在</p>
<p>也就是说,有没有什么方法可以强制执行正确的z顺序,以使事情快速运转?看来,我所能说的就是,正确的透明蓝色飞机在其他一切之上。然而,将zorder参数放入PolyCollection似乎没有任何效果,而在绘制读取线的plot函数中放入一个显式的zorder参数将扰乱其相对于绿色曲面的顺序。在</p>
<p>有没有一种方法可以将正确的蓝色透明表面强加于所有物体之上?以下是我目前掌握的代码:</p>
<pre><code>#!/bin/env python3
from pylab import *
from mpl_toolkits.mplot3d import *
from matplotlib.collections import PolyCollection
from matplotlib.colors import colorConverter
from matplotlib.patches import FancyArrowPatch
rc('text', usetex=True)
rc('font', size=20)
fig = figure(figsize=(11,6))
ax = fig.gca(projection='3d')
ax.set_axis_off()
def f(x,t):
return t/2 * 0.55*(sin(2*x)+0.4*x**2-0.65)
c_plane = colorConverter.to_rgba('b', alpha=0.15)
N = 50
y = linspace(-1,1,N)
t = linspace(0,2,N)
yy, tt = meshgrid(y, t)
zz = f(yy,tt)
ax.plot(0*ones(y.shape), y, f(y,0), '-g', linewidth=3)
ax.plot(2*ones(y.shape), y, f(y,2), '-g', linewidth=3)
yt = 0.7*y
zt = f(yt, t) + 0.2*t
ax.plot(t, yt, zt, '-r', linewidth=3)
ax.plot((0,2), (yt[0], yt[-1]), (zt[0], zt[-1]), 'or')
ax.plot([2,2,2], [-1,yt[-1],yt[-1]], [zt[-1],zt[-1],-1], 'k--')
ax.plot(2*ones(y.shape), yt, f(yt,2)+0.1*(y+1), 'g:', linewidth=2)
ax.plot((2,2),
(yt[0], yt[-1]),
(f(yt[0], 2), f(yt[-1], 2) + 0.1*(y[-1]+1)), 'og')
ax.plot((0,2,2),
(-1,-1,zt[-1]),
(0,yt[-1],-1), 'ok')
ax.text(0, -1.1, 0, r'$p(0)=0$', ha='right', va='center')
ax.text(2, -1.05, zt[-1], r'$p(T)$', ha='right', va='center')
ax.text(0, -1.0, 1, r'$p$', ha='right', va='bottom')
ax.text(0, 1, -1.1, r'$q$', ha='center', va='top')
ax.text(0, -1, -1.1, r'$t=0$', ha='right', va='top')
ax.text(2, -1, -1.1, r'$t=T$', ha='right', va='top')
ax.text(2, yt[-1]-0.05, -1.05, r'$q(T)=q^*$', ha='left', va='top')
ax.text(0, 0.5, 0.05, r'$\mathcal{M}(0)$', ha='center', va='bottom')
ax.text(2, 0.1, -0.8, r'$\mathcal{M}(T)$', ha='center', va='bottom')
arrowprops = dict(mutation_scale=20,
linewidth=2,
arrowstyle='-|>',
color='k')
# For arrows, see
# https://stackoverflow.com/questions/29188612/arrows-in-matplotlib-using-mplot3d
class Arrow3D(FancyArrowPatch):
def __init__(self, xs, ys, zs, *args, **kwargs):
FancyArrowPatch.__init__(self, (0,0), (0,0), *args, **kwargs)
self._verts3d = xs, ys, zs
def draw(self, renderer):
xs3d, ys3d, zs3d = self._verts3d
xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M)
self.set_positions((xs[0],ys[0]),(xs[1],ys[1]))
FancyArrowPatch.draw(self, renderer)
a = Arrow3D([0,2], [-1,-1], [-1,-1], **arrowprops)
ax.add_artist(a)
a = Arrow3D([0,0], [-1,-1], [-1,1], **arrowprops)
ax.add_artist(a)
a = Arrow3D([0,0], [-1,1], [-1,-1], **arrowprops)
ax.add_artist(a)
# For surface illumination, see
# http://physicalmodelingwithpython.blogspot.de/2015/08/illuminating-surface-plots.html
# Get lighting object for shading surface plots.
from matplotlib.colors import LightSource
# Get colormaps to use with lighting object.
from matplotlib import cm
# Create an instance of a LightSource and use it to illuminate the surface.
light = LightSource(70, -120)
white = np.ones((zz.shape[0], zz.shape[1], 3))
illuminated_surface = light.shade_rgb(white*(0,1,0), zz)
ax.plot_surface(tt, yy, zz,
cstride=1, rstride=1,
alpha=0.3, facecolors=illuminated_surface,
linewidth=0)
verts = [array([(-1,-1), (-1,1), (1,1), (1,-1), (-1,-1)])]
poly = PolyCollection(verts, facecolors=c_plane)
ax.add_collection3d(poly, zs=[0], zdir='x')
poly = PolyCollection(verts, facecolors=c_plane)
ax.add_collection3d(poly, zs=[2], zdir='x')
ax.set_xlim3d(0, 2)
ax.view_init(elev=18, azim=-54)
show()
</code></pre>