DL-Art-School/codes/data/stylegan2_dataset.py

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from functools import partial
from random import random
import torch
import torchvision
from PIL import Image
from torch.utils import data
from torchvision import transforms
import torch.nn as nn
from pathlib import Path
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import models.stylegan.stylegan2_lucidrains as sg2
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def convert_transparent_to_rgb(image):
if image.mode != 'RGB':
return image.convert('RGB')
return image
def convert_rgb_to_transparent(image):
if image.mode != 'RGBA':
return image.convert('RGBA')
return image
def resize_to_minimum_size(min_size, image):
if max(*image.size) < min_size:
return torchvision.transforms.functional.resize(image, min_size)
return image
class RandomApply(nn.Module):
def __init__(self, prob, fn, fn_else=lambda x: x):
super().__init__()
self.fn = fn
self.fn_else = fn_else
self.prob = prob
def forward(self, x):
fn = self.fn if random() < self.prob else self.fn_else
return fn(x)
class expand_greyscale(object):
def __init__(self, transparent):
self.transparent = transparent
def __call__(self, tensor):
channels = tensor.shape[0]
num_target_channels = 4 if self.transparent else 3
if channels == num_target_channels:
return tensor
alpha = None
if channels == 1:
color = tensor.expand(3, -1, -1)
elif channels == 2:
color = tensor[:1].expand(3, -1, -1)
alpha = tensor[1:]
else:
raise Exception(f'image with invalid number of channels given {channels}')
if not sg2.exists(alpha) and self.transparent:
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alpha = torch.ones(1, *tensor.shape[1:], device=tensor.device)
return color if not self.transparent else torch.cat((color, alpha))
class Stylegan2Dataset(data.Dataset):
def __init__(self, opt):
super().__init__()
EXTS = ['jpg', 'jpeg', 'png']
self.folder = opt['path']
self.image_size = opt['target_size']
self.paths = [p for ext in EXTS for p in Path(f'{self.folder}').glob(f'**/*.{ext}')]
aug_prob = opt['aug_prob']
transparent = opt['transparent'] if 'transparent' in opt.keys() else False
assert len(self.paths) > 0, f'No images were found in {self.folder} for training'
convert_image_fn = convert_transparent_to_rgb if not transparent else convert_rgb_to_transparent
num_channels = 3 if not transparent else 4
self.transform = transforms.Compose([
transforms.Lambda(convert_image_fn),
transforms.Lambda(partial(resize_to_minimum_size, self.image_size)),
transforms.Resize(self.image_size),
RandomApply(aug_prob, transforms.RandomResizedCrop(self.image_size, scale=(0.5, 1.0), ratio=(0.98, 1.02)),
transforms.CenterCrop(self.image_size)),
transforms.ToTensor(),
transforms.Lambda(expand_greyscale(transparent))
])
def __len__(self):
return len(self.paths)
def __getitem__(self, index):
path = self.paths[index]
img = Image.open(path)
img = self.transform(img)
return {'lq': img, 'hq': img, 'GT_path': str(path)}