Closed
Description
Bug report
Bug summary
As noted in #8802, the pcolormesh test stages a masked array but does not use it. This is probably because masked array support is broken in PDF output with the gouraud shading option.
Code for reproduction
This is a modification of the test_axes.test_pcolormesh function:
import matplotlib.pyplot as plt
import numpy as np
def test_pcolormesh():
n = 12
x = np.linspace(-1.5, 1.5, n)
y = np.linspace(-1.5, 1.5, n*2)
X, Y = np.meshgrid(x, y)
Qx = np.cos(Y) - np.cos(X)
Qz = np.sin(Y) + np.sin(X)
Qx = (Qx + 1.1)
Z = np.hypot(X, Y) / 5
Z = (Z - Z.min()) / Z.ptp()
# The color array can include masked values:
Zm = np.ma.masked_where(np.abs(Qz) < 0.5 * np.max(Qz), Z)
fig, axs = plt.subplots(2, 3)
kw = dict(vmin=0, vmax=1)
for ax, zz in zip(axs, [Z, Zm]):
ax[0].pcolormesh(Qx, Qz, zz, lw=0.5, edgecolors='k', **kw)
ax[1].pcolormesh(Qx, Qz, zz, lw=2, edgecolors=['b', 'w'], **kw)
ax[2].pcolormesh(Qx, Qz, zz, shading="gouraud", **kw)
return fig
fig = test_pcolormesh()
fig.savefig('test_pcolormesh.png')
fig.savefig('test_pcolormesh.pdf')Actual outcome
The pdf (converted to a png for display here) is black in the masked region with gouraud shading:
but the png is as expected.
