melpomene/zooms_generator.py

# Melpomene webcomic reader JSON/JS/HTML generator
# Version 1.0.0_UNSTABLE
# CC-BY-NC-SA https://git.aribaud.net/caribaud/melpomene/

import sys
import re
import xml.etree.ElementTree as ET
import argparse

from pathlib import Path


HTML_TEMPLATE = Path(__file__).parent / "melpomene.html"
HTML_TO_REPLACE = "<!-- your img tags here, see documentation -->"


def extract_zooms(src_folder):
    folder = Path(src_folder)

    zooms = {}
    
    max_width = 0
    max_height = 0
    
    idx = 0

    for svg_path in folder.glob("*.svg"):
        
        idx += 1
    
        print(f"page {idx} : {svg_path.name}")
    
        zooms[idx] = {
            "name": svg_path.stem,
            "width": 0,
            "height": 0,
            "zooms": [],
        }
    
        tree = ET.parse(svg_path)
        root = tree.getroot()

        zooms[idx]["width"] = int(root.get("width"))
        zooms[idx]["height"] = int(root.get("height"))
        
        for area in root.findall('.//{*}rect'):
            zooms[idx]["zooms"].append([
                float(area.get("width")),
                float(area.get("height")),
                float(area.get("x")),
                float(area.get("y")),
            ])

    return zooms, max_width, max_height


def write_json_or_js(zooms, dest_file, is_js):

    with open(dest_file, "w") as data_file:
    
        if is_js:
            data_file.write("PAGES_ZOOMS = ")
        data_file.write("[\n")
        first_coma_skiped = False
        for page_idx in sorted(zooms.keys()):
            for zoom in zooms[page_idx]["zooms"]:
            
                if zoom[2] < 0 or zoom[3] < 0 :
                    print(f"WARNING: negative pos x / pos y in page {page_idx} for zoom {zoom} (is the rectangle flipped?)")
            
                if first_coma_skiped:
                    data_file.write(",\n")
                else:
                    first_coma_skiped = True
                data_file.write(f"    {[page_idx] + zoom}")
        data_file.write("\n]\n")


def write_html(zooms, dest_file, pages_width, pages_height, prefix, extention):
    
    img_tags = ""
    for page_idx in sorted(zooms.keys()):
        img_url = f"{prefix}{zooms[page_idx]['name']}.{extention}"
        zoom_html_data = [','.join([str(zoom) for zoom in page_zooms]) for page_zooms in zooms[page_idx]["zooms"]]
        zoom_html_str = ';'.join(zoom_html_data)
        img_tags = img_tags + f'            <img loading="lazy" height="{zooms[page_idx]["height"]}" width="{zooms[page_idx]["width"]}" src="{img_url}" data-zooms="{zoom_html_str}"/>\n'
    
    img_tags = img_tags.strip()
    
    with open(HTML_TEMPLATE) as template_file, open(dest_file, "w") as data_file:
        
        data = template_file.read().replace(HTML_TO_REPLACE, img_tags)
    
        data_file.write(data)


def generate_argparse():
    """ Generate Melpomene's generator input parser"""
    
    parser = argparse.ArgumentParser(
        description="Helper that can generate JSON / JS / HTML files for Melpomene webcomic reader"
    )
    
    parser.add_argument("output_format", choices=["html", "json", "js"], help="The type of output to generate")
    parser.add_argument("svg_folders", help="Path of the folder containing the SVGs")
    parser.add_argument("-o", metavar="dest_file", help="Where to write the generator output to")
    parser.add_argument("-p", default="", metavar="img_url_prefix", help="What to prefix the URL of the images when using HTML format.")
    parser.add_argument("-e", default="png", metavar="img_ext", help="What extention to use in the URL of the images when using HTML format.")
    
    return parser


if __name__ == "__main__":

    args = generate_argparse().parse_args()
    
    
    # Get the final outout name
    output = None
    
    if not args.o:
        output = "melpomene_data"
    else:
        output = args.o
    
    if args.output_format == "html" and not output.endswith(".html"):
        output += ".html"
    
    elif args.output_format == "json" and not output.endswith(".json"):
        output += ".json"
    
    elif args.output_format == "js" and not output.endswith(".js"):
        output += ".js"
    
    zooms, max_width, max_height = extract_zooms(args.svg_folders)

    if args.output_format == "html":
        write_html(zooms, output, max_width, max_height, args.p, args.e)
    
    elif args.output_format == "json":
        write_json_or_js(zooms, output, False)
    
    elif args.output_format == "js":
        write_json_or_js(zooms, output, True)