WireViz/src/wireviz/svgembed.py
2021-10-16 22:39:41 +02:00

53 lines
1.7 KiB
Python

# -*- coding: utf-8 -*-
import base64
import re
from pathlib import Path
from typing import Union
mime_subtype_replacements = {"jpg": "jpeg", "tif": "tiff"}
def embed_svg_images(svg_in: str, base_path: Union[str, Path] = Path.cwd()) -> str:
images_b64 = {} # cache of base64-encoded images
def image_tag(pre: str, url: str, post: str) -> str:
return f'<image{pre} xlink:href="{url}"{post}>'
def replace(match: re.Match) -> str:
imgurl = match["URL"]
if not imgurl in images_b64: # only encode/cache every unique URL once
imgurl_abs = (Path(base_path) / imgurl).resolve()
image = imgurl_abs.read_bytes()
images_b64[imgurl] = base64.b64encode(image).decode("utf-8")
return image_tag(
match["PRE"] or "",
f"data:image/{get_mime_subtype(imgurl)};base64, {images_b64[imgurl]}",
match["POST"] or "",
)
pattern = re.compile(
image_tag(r"(?P<PRE> [^>]*?)?", r'(?P<URL>[^"]*?)', r"(?P<POST> [^>]*?)?"),
re.IGNORECASE,
)
return pattern.sub(replace, svg_in)
def get_mime_subtype(filename: Union[str, Path]) -> str:
mime_subtype = Path(filename).suffix.lstrip(".").lower()
if mime_subtype in mime_subtype_replacements:
mime_subtype = mime_subtype_replacements[mime_subtype]
return mime_subtype
def embed_svg_images_file(
filename_in: Union[str, Path], overwrite: bool = True
) -> None:
filename_in = Path(filename_in).resolve()
filename_out = filename_in.with_suffix(".b64.svg")
filename_out.write_text(
embed_svg_images(filename_in.read_text(), filename_in.parent)
)
if overwrite:
filename_out.replace(filename_in)