utils.py

import json
import logging
import os
import shutil
import matplotlib.pyplot as plt


class Params():
    """Class that loads hyperparameters from a json file.
    Example:
    ```
    params = Params(json_path)
    print(params.learning_rate)
    params.learning_rate = 0.5 
    ```
    """

    def __init__(self, json_path):
        with open(json_path) as f:
            params = json.load(f)
            self.__dict__.update(params)

    def save(self, json_path):
        with open(json_path, 'w') as f:
            json.dump(self.__dict__, f, indent=4)

    def update(self, json_path):
        """Loads parameters from json file"""
        with open(json_path) as f:
            params = json.load(f)
            self.__dict__.update(params)

    @property
    def dict(self):
        """Gives dict-like access to Params instance by params.dict['learning_rate']"""
        return self.__dict__
    

def image_grid(
    images,
    rows=None,
    cols=None,
    fill: bool = True,
    show_axes: bool = False,
    rgb: bool = True,
):
    """
    A util function for plotting a grid of images.

    Args:
        images: (N, H, W, 4) array of RGBA images
        rows: number of rows in the grid
        cols: number of columns in the grid
        fill: boolean indicating if the space between images should be filled
        show_axes: boolean indicating if the axes of the plots should be visible
        rgb: boolean, If True, only RGB channels are plotted.
            If False, only the alpha channel is plotted.

    Returns:
        None
    """
    if (rows is None) != (cols is None):
        raise ValueError("Specify either both rows and cols or neither.")

    if rows is None:
        rows = len(images)
        cols = 1

    gridspec_kw = {"wspace": 0.0, "hspace": 0.0} if fill else {}
    fig, axarr = plt.subplots(rows, cols, gridspec_kw=gridspec_kw, figsize=(15, 9))
    bleed = 0
    fig.subplots_adjust(left=bleed, bottom=bleed, right=(1 - bleed), top=(1 - bleed))

    for ax, im in zip(axarr.ravel(), images):
        if rgb:
            # only render RGB channels
            ax.imshow(im[..., :3])
        else:
            # only render Alpha channel
            ax.imshow(im[..., 3])
        if not show_axes:
            ax.set_axis_off()