src/alto.py

import os

from datasets import load_dataset
from dataclasses import dataclass, field
import tqdm.auto as tqdm
from typing import List, Dict, Set
from jinja2 import Environment, FileSystemLoader
from shapely.geometry import Polygon
import itertools

# Load the Jinja2 template
env = Environment(loader=FileSystemLoader('.'))
template = env.get_template('template.xml')

ds = load_dataset("CATMuS/medieval-segmentation")

RATIO = .05


@dataclass
class Tag:
    idx: str
    label: str
    element_type: str


@dataclass
class Line:
    idx: str
    bbox: List[int]
    polygons: List[int]
    category: str
    baseline: List[int]

    @property
    def simple_polygon(self):
        x = list(
            map(
                int,
                itertools.chain(
                    *Polygon(
                        list(zip(self.polygons[::2], self.polygons[1::2]))  # Flat list to list of points
                    ).simplify(RATIO * self.height).exterior.coords
                )
            )
        )[:-2]  # Polygon repeats the starting point
        return x

    @property
    def hpos(self):
        return self.bbox[0]

    @property
    def vpos(self):
        return self.bbox[1]

    @property
    def width(self):
        return self.bbox[2] - self.bbox[0]

    @property
    def height(self):
        return self.bbox[3] - self.bbox[1]


@dataclass
class Block:
    idx: str
    bbox: List[int]
    polygons: List[int]
    category: str
    lines: List[Line] = field(default_factory=list)

    @property
    def hpos(self):
        return self.bbox[0]

    @property
    def vpos(self):
        return self.bbox[1]

    @property
    def width(self):
        return self.bbox[2] - self.bbox[0]

    @property
    def height(self):
        return self.bbox[3] - self.bbox[1]


for split in ds:
    print(f"Split: {split}")
    os.makedirs(f"altos/{split}", exist_ok=True)
    for image_idx, image in enumerate(tqdm.tqdm(ds[split])):
        blocks: Dict[str, Block] = {}
        tags: Dict[str, Tag] = {}
        print(image)
        for idx, bbox, polygons, category, typ, parent, baseline in zip(*[
            image["objects"][key]
            for key in ['id', 'bbox', 'polygons', 'category', 'type', 'parent', "baselines"]
        ]):
            if category and category not in tags:
                tags[category] = Tag(f"LABEL_{len(tags)}", category, typ)

            if typ == "block":
                blocks[idx] = Block(idx, bbox, polygons, category)
            else:
                if parent == None:
                    blocks[None] = Block(None, [], [], "")
                blocks[parent].lines.append(
                    Line(idx, bbox, polygons, category)
                )
        image["image"].save(f"./altos/{split}/image-{image_idx:04}.jpg")
        with open(f"./altos/{split}/image-{image_idx:04}.xml", "w") as f:
            f.write(
                template.render(
                    blocks=blocks,
                    image=image,
                    path=f"image-{image_idx:04}.jpg",
                    tags=tags
                )
            )
        break