extendedimage.py


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"""
Like the standard ![alt text](src.img title_text) image format in Markdown, but with two extra parameters.

Usage:
![alt text](src.img title_text href figcapture)
href:       if not empty, encapsulates image in <a> with the specified url
figcapture: if not empty, encapsulates image in a <figure> with the specified figcapture

ALL PARAMETERS ARE MANDATORY!
Parameters can be encapsulated in double-quotes. Use "" for empty parameter.
"""
from marko import inline
from marko.helpers import MarkoExtension


class ExtendedImageElement(inline.InlineElement):
    pattern = r'!\[(.*)\]\(((?:[^"\s\\]|\\.)+|"(?:[^"\\]|\\.)*")\s((?:[^"\s\\]|\\.)+|"(?:[^"\\]|\\.)*")\s((?:[^"\s\\]|\\.)+|"(?:[^"\\]|\\.)*")\s((?:[^"\s\\]|\\.)+|"(?:[^"\\]|\\.)*")\)'
    parse_children = True

    def __init__(self, match):
        self.alt = self.__strip_quotes(match.group(1))
        self.src = self.__strip_quotes(match.group(2))
        self.title = self.__strip_quotes(match.group(3))
        self.href = self.__strip_quotes(match.group(4))
        self.figcaption = self.__strip_quotes(match.group(5))

    @staticmethod
    def __strip_quotes(text: str) -> str:
        if text.startswith('"'):
            return text[1:-1]

        return text


class ExtendedImageRenderer:
    def render_extended_image_element(self, element):
        img = f'<img src="{element.src}" title="{element.title}" alt="{element.alt}" />'

        if element.href != "":
            img = f'<a href="{element.href}">{img}</a>'

        if element.figcaption != "":
            img = f"<figure>{img}<figcaption>{element.figcaption}</figcaption></figure>"

        return img


ExtendedImage = MarkoExtension(
    elements=[ExtendedImageElement],
    renderer_mixins=[ExtendedImageRenderer]
)