dataset/font_dataset.py

import os
import random
from PIL import Image

from torch.utils.data import Dataset
import torchvision.transforms as transforms

def get_nonorm_transform(resolution):
    nonorm_transform =  transforms.Compose(
            [transforms.Resize((resolution, resolution), 
                               interpolation=transforms.InterpolationMode.BILINEAR), 
             transforms.ToTensor()])
    return nonorm_transform


class FontDataset(Dataset):
    """The dataset of font generation  
    """
    def __init__(self, args, phase, transforms=None):
        super().__init__()
        self.root = args.data_root
        self.phase = phase
        
        # Get Data path
        self.get_path()
        self.transforms = transforms
        self.nonorm_transforms = get_nonorm_transform(args.resolution)

    def get_path(self):
        self.target_images = []
        # images with related style  
        self.style_to_images = {}
        target_image_dir = f"{self.root}/{self.phase}/TargetImage"
        for style in os.listdir(target_image_dir):
            images_related_style = []
            for img in os.listdir(f"{target_image_dir}/{style}"):
                img_path = f"{target_image_dir}/{style}/{img}"
                self.target_images.append(img_path)
                images_related_style.append(img_path)
            self.style_to_images[style] = images_related_style

    def __getitem__(self, index):
        target_image_path = self.target_images[index]
        target_image_name = target_image_path.split('/')[-1]
        style, content = target_image_name.split('.')[0].split('+')
        
        # Read content image
        content_image_path = f"{self.root}/{self.phase}/ContentImage/{content}.jpg"
        content_image = Image.open(content_image_path).convert('RGB')

        # Random sample used for style image
        images_related_style = self.style_to_images[style].copy()
        images_related_style.remove(target_image_path)
        style_image_path = random.choice(images_related_style)
        style_image = Image.open(style_image_path).convert("RGB")
        
        # Read target image
        target_image = Image.open(target_image_path).convert("RGB")
        nonorm_target_image = self.nonorm_transforms(target_image)

        if self.transforms is not None:
            content_image = self.transforms[0](content_image)
            style_image = self.transforms[1](style_image)
            target_image = self.transforms[2](target_image)
        
        return content_image, style_image, target_image, nonorm_target_image, target_image_path

    def __len__(self):
        return len(self.target_images)