gan_utils.py

# Code adapted from the following sources:
# https://huggingface.co/huggan/fastgan-few-shot-fauvism-still-life
# https://huggingface.co/spaces/huggan/FastGan/

import torch
from PIL import Image

from models import Generator


def load_img_generator(model_name_or_path):
    generator = Generator(in_channels=256, out_channels=3)
    generator = generator.from_pretrained(model_name_or_path, in_channels=256, out_channels=3)
    _ = generator.eval()

    return generator


def _denormalize(input: torch.Tensor) -> torch.Tensor:
    return (input * 127.5) + 127.5


def generate_img(device, gan_model):
    img_generator = load_img_generator("huggan/fastgan-few-shot-"+gan_model)
    noise = torch.zeros(1, 256, 1, 1, device=device).normal_(0.0, 1.0)
    with torch.no_grad():
        gan_images, _ = img_generator(noise)
    gan_image = _denormalize(gan_images.detach()).cpu().squeeze()
    gan_image = gan_image.permute(1, 2, 0).to("cpu", torch.uint8).numpy()
    gan_image = Image.fromarray(gan_image)
    return gan_image