34 lines
1.0 KiB
Python
34 lines
1.0 KiB
Python
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import numpy as np
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import matplotlib.pyplot as plt
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from matplotlib.testing.decorators import image_comparison
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@image_comparison(baseline_images=['agg_filter_alpha'],
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extensions=['png', 'pdf'])
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def test_agg_filter_alpha():
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# Remove this line when this test image is regenerated.
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plt.rcParams['pcolormesh.snap'] = False
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ax = plt.axes()
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x, y = np.mgrid[0:7, 0:8]
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data = x**2 - y**2
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mesh = ax.pcolormesh(data, cmap='Reds', zorder=5)
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def manual_alpha(im, dpi):
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im[:, :, 3] *= 0.6
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print('CALLED')
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return im, 0, 0
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# Note: Doing alpha like this is not the same as setting alpha on
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# the mesh itself. Currently meshes are drawn as independent patches,
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# and we see fine borders around the blocks of color. See the SO
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# question for an example: https://stackoverflow.com/questions/20678817
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mesh.set_agg_filter(manual_alpha)
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# Currently we must enable rasterization for this to have an effect in
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# the PDF backend.
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mesh.set_rasterized(True)
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ax.plot([0, 4, 7], [1, 3, 8])
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