How to show y-axis of subtracks?

[phyto]

Dear Moshi4,
Do you have any suggestions on how to show the y axis for subtracks? For instance, with the first "subtrack" example in your "plot tips" doc section, how to display the y axis and '50', '75' and '100' ticks for the subtrack? Thank you!

[moshi4]

Code Example

from pygenomeviz import GenomeViz
import numpy as np
np.random.seed(0)

genome_list = [
    dict(name="genome 01", size=1000, features=((150, 300, 1), (500, 700, -1), (750, 950, 1))),
    dict(name="genome 02", size=1300, features=((50, 200, 1), (350, 450, 1), (700, 900, -1), (950, 1150, -1))),
    dict(name="genome 03", size=1200, features=((150, 300, 1), (350, 450, -1), (500, 700, -1), (700, 900, -1))),
]

gv = GenomeViz(fig_track_height=0.7, feature_track_ratio=0.5, track_align_type="center")
gv.set_scale_bar()

for genome in genome_list:
    name, size, features = genome["name"], genome["size"], genome["features"]
    track = gv.add_feature_track(name, size)
    track.add_subtrack(ylim=(0, 100)) # Add subtrack
    for idx, feature in enumerate(features, 1):
        start, end, strand = feature
        track.add_feature(start, end, strand, plotstyle="bigarrow", lw=1)

fig = gv.plotfig()

# Plot user-defined graph to subtrack axes
for track in gv.feature_tracks:
    subtrack = track.get_subtrack()
+   subtrack.ax.tick_params(left=True, labelleft=True)
+   subtrack.ax.spines["left"].set_position(("data", track.transform_coord(0)))
+   subtrack.ax.set_yticks([0, 50, 100], [0, 50, 100])
    for segment in track.segments:
        # Plot y = (50 - 100) random values to subtrack
        # Tranform segment-level x coordinate to track-level coordinate
        x = np.arange(segment.start, segment.end, 10)
        x = segment.transform_coord(x)
        y = np.random.randint(50, 100, len(x))
        subtrack.ax.fill_between(x, y, color="grey")

fig.savefig("result.png")

result.png

Knowledge of matplotlib is required for additional plots on subtracks.
If you want to know more details, please learn about Axes in matplotlib.