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# -*- coding: utf-8 -*-
import numpy as np
from vispy.scene.visuals import Spectrogram
from vispy.testing import (requires_application, TestingCanvas,
run_tests_if_main, raises)
from vispy.testing.image_tester import assert_image_approved
@requires_application()
def test_spectrogram():
"""Test spectrogram visual"""
n_fft = 256
n_freqs = n_fft // 2 + 1
size = (100, n_freqs)
with TestingCanvas(size=size) as c:
np.random.seed(67853498)
data = np.random.normal(size=n_fft * 100)
spec = Spectrogram(data, n_fft=n_fft, step=n_fft, window=None,
color_scale='linear', cmap='grays')
c.draw_visual(spec)
# expected = np.zeros(size[::-1] + (3,))
# expected[0] = 1.
assert_image_approved("screenshot", "visuals/spectrogram.png")
freqs = spec.freqs
assert len(freqs) == n_freqs
assert freqs[0] == 0
assert freqs[-1] == 0.5
# Try changing all properties
spec.n_fft = 128
spec.step = 128
spec.fs = 2
spec.window = 'hann'
spec.normalize = True
spec.color_scale = 'log'
# Check color scale can be only 'log' or 'linear'
with raises(ValueError):
spec.color_scale = 'line_log'
run_tests_if_main()
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