What we want to do ?¶
When we want to plot mesh it cost a lot to code.
[1]:
%matplotlib inline
import meshio
import matplotlib
import getfem as gf
import numpy as np
import matplotlib.pyplot as plt
[2]:
m = gf.Mesh("cartesian", np.arange(3), np.arange(3))
[3]:
m.export_to_vtk("m.vtk", "ascii")
[4]:
!cat m.vtk
# vtk DataFile Version 2.0
Exported by getfem++
ASCII
DATASET UNSTRUCTURED_GRID
POINTS 9 float
0 0 0
1 0 0
0 1 0
1 1 0
2 0 0
2 1 0
0 2 0
1 2 0
2 2 0
CELLS 4 20
4 0 1 3 2
4 1 4 5 3
4 2 3 7 6
4 3 5 8 7
CELL_TYPES 4
9
9
9
9
[5]:
mesh = meshio.read("m.vtk")
[6]:
points = mesh.points
cells = mesh.cells
[7]:
cells
[7]:
[CellBlock(type='quad', data=array([[0, 1, 3, 2],
[1, 4, 5, 3],
[2, 3, 7, 6],
[3, 5, 8, 7]]))]
[8]:
figure = plt.figure()
axe = figure.add_subplot(111)
for cell in cells:
for index in cell.data:
polygon = plt.Polygon(
(
(points[index[0], 0], points[index[0], 1]),
(points[index[1], 0], points[index[1], 1]),
(points[index[2], 0], points[index[2], 1]),
(points[index[3], 0], points[index[3], 1]),
),
edgecolor="black",
facecolor="gray",
)
axe.add_patch(polygon)
axe.set_aspect("equal")
plt.xlim(-1.0, 3.0)
plt.ylim(-1.0, 3.0)
plt.show()
[9]:
axe?
Type: AxesSubplot
String form: AxesSubplot(0.260833,0.125;0.503333x0.755)
File: /usr/local/lib/python3.8/dist-packages/matplotlib/axes/_subplots.py
Docstring: <no docstring>
Class docstring:
Base class for subplots, which are :class:`Axes` instances with
additional methods to facilitate generating and manipulating a set
of :class:`Axes` within a figure.
Init docstring:
Parameters
----------
fig : `matplotlib.figure.Figure`
*args : tuple (*nrows*, *ncols*, *index*) or int
The array of subplots in the figure has dimensions ``(nrows,
ncols)``, and *index* is the index of the subplot being created.
*index* starts at 1 in the upper left corner and increases to the
right.
If *nrows*, *ncols*, and *index* are all single digit numbers, then
*args* can be passed as a single 3-digit number (e.g. 234 for
(2, 3, 4)).
**kwargs
Keyword arguments are passed to the Axes (sub)class constructor.
What we can do in meshioplt¶
We can read mesh file and write to AxesSubplot. We can use AxesSubplot as matplotlib’s AxesSubplot
[10]:
from meshioplt import mesh_patches
figure = plt.figure()
axe = figure.add_subplot(111)
patches = mesh_patches("m.vtk")
for patch in patches:
axe.add_patch(patch)
axe.set_aspect("equal")
plt.xlim(-1.0, 3.0)
plt.ylim(-1.0, 3.0)
plt.show()
