"""
Fractional Extent Layout
========================

Create subplots using extents given as fractions of the canvas.
This example plots two images and their histograms in separate subplots

"""

# test_example = true
# sphinx_gallery_pygfx_docs = 'screenshot'

import numpy as np
import imageio.v3 as iio
import fastplotlib as fpl

# load images
img1 = iio.imread("imageio:astronaut.png")
img2 = iio.imread("imageio:wikkie.png")

# calculate histograms
hist_1, edges_1 = np.histogram(img1)
centers_1 = edges_1[:-1] + np.diff(edges_1) / 2

hist_2, edges_2 = np.histogram(img2)
centers_2 = edges_2[:-1] + np.diff(edges_2) / 2

# figure size in pixels
size = (700, 560)

# extent is (xmin, xmax, ymin, ymax)
# here it is defined as fractions of the canvas
extents = [
    (0, 0.3, 0, 0.5),  # for image1
    (0, 0.3, 0.5, 1),  # for image2
    (0.3, 1, 0, 0.5),  # for image1 histogram
    (0.3, 1, 0.5, 1),  # for image2 histogram
]

# create a figure using the rects and size
# also give each subplot a name
figure = fpl.Figure(
    extents=extents,
    names=["astronaut image", "wikkie image", "astronaut histogram", "wikkie histogram"],
    size=size
)

# add image to the corresponding subplots
figure["astronaut image"].add_image(img1)
figure["wikkie image"].add_image(img2)

# add histogram to the corresponding subplots
figure["astronaut histogram"].add_line(np.column_stack([centers_1, hist_1]))
figure["wikkie histogram"].add_line(np.column_stack([centers_2, hist_2]))


for subplot in figure:
    if "image" in subplot.name:
        # remove axes from image subplots to reduce clutter
        subplot.axes.visible = False
        continue

    # don't maintain aspect ratio for the histogram subplots
    subplot.camera.maintain_aspect = False


figure.show()


# NOTE: fpl.loop.run() should not be used for interactive sessions
# See the "JupyterLab and IPython" section in the user guide
if __name__ == "__main__":
    print(__doc__)
    fpl.loop.run()