A FEniCS Tutorial - FEniCS Project

Figure 3: Plot of the deflection of a membrane.
extension of PNG files is .png instead of .eps). Pressing o adds a red outline
of a bounding box around the domain.
One can alternatively control the visualization from the program code directly.
This is done through a Viper object returned from the plot command.
Let us grab this object and use it to 1) tilt the camera −65 degrees in the latitude
direction, 2) add x and y axes, 3) change the default name of the plot files,
4) change the color scale, and 5) write the plot to a PNG and an EPS file. Here
is the code:
viz_w = plot(w,
wireframe=False,
title=’Scaled membrane deflection’,
rescale=False,
axes=True, # include axes
basename=’deflection’, # default plotfile name
)
viz_w.elevate(-65) # tilt camera -65 degrees (latitude dir)
viz_w.set_min_max(0, 0.5*max_w) # color scale
viz_w.update(w) # bring settings above into action
viz_w.write_png(’deflection.png’)
viz_w.write_ps(’deflection’, format=’eps’)
The format argument in the latter line can also take the values ’ps’ for a
standard PostScript file and ’pdf’ for a PDF file. Note the necessity of the
viz_w.update(w) call – without it we will not see the effects of tilting the
camera and changing the color scale. Figure 3 shows the resulting scalar surface.
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