aafig.py

"""
    sphinxcontrib.aafig
    ~~~~~~~~~~~~~~~~~~~

    Allow embeded ASCII art to be rendered as nice looking images
    using the aafigure reStructuredText extension.

    See the README file for details.

    :author: Leandro Lucarella <llucax@gmail.com>
    :license: BOLA, see LICENSE for details
"""
import posixpath
from os import path

from docutils import nodes
from docutils.parsers.rst.directives import flag, images, nonnegative_int
from sphinx.errors import SphinxError
from sphinx.util import ensuredir, logging, relative_uri

try:
    from hashlib import sha1 as sha
except ImportError:
    from sha import sha


try:
    import aafigure
except ImportError:
    aafigure = None


logger = logging.getLogger(__name__)

DEFAULT_FORMATS = dict(html="svg", latex="pdf", text=None)


def merge_dict(dst, src):
    for (k, v) in src.items():
        if k not in dst:
            dst[k] = v
    return dst


def get_basename(text, options, prefix="aafig"):
    options = options.copy()
    if "format" in options:
        del options["format"]
    hashkey = text + str(options)
    id = sha(hashkey.encode("utf-8")).hexdigest()
    return "%s-%s" % (prefix, id)


class AafigError(SphinxError):
    category = "aafig error"


class AafigDirective(images.Image):
    """
    Directive to insert an ASCII art figure to be rendered by aafigure.
    """

    has_content = True
    required_arguments = 0
    own_option_spec = dict(
        line_width=float,
        background=str,
        foreground=str,
        fill=str,
        aspect=nonnegative_int,
        textual=flag,
        proportional=flag,
    )
    option_spec = images.Image.option_spec.copy()
    option_spec.update(own_option_spec)

    def run(self):
        aafig_options = dict()
        own_options_keys = [self.own_option_spec.keys()] + ["scale"]
        for (k, v) in self.options.items():
            if k in own_options_keys:
                # convert flags to booleans
                if v is None:
                    v = True
                # convert percentage to float
                if k == "scale" or k == "aspect":
                    v = float(v) / 100.0
                aafig_options[k] = v
                del self.options[k]
        self.arguments = [""]
        (image_node,) = images.Image.run(self)
        if isinstance(image_node, nodes.system_message):
            return [image_node]
        text = "\n".join(self.content)
        image_node.aafig = dict(options=aafig_options, text=text)
        return [image_node]


def render_aafig_images(app, doctree):
    format_map = app.builder.config.aafig_format
    merge_dict(format_map, DEFAULT_FORMATS)
    if aafigure is None:
        logger.warn(
            "aafigure module not installed, ASCII art images "
            "will be redered as literal text"
        )
    for img in doctree.traverse(nodes.image):
        if not hasattr(img, "aafig"):
            continue
        if aafigure is None:
            continue
        options = img.aafig["options"]
        text = img.aafig["text"]
        format = app.builder.format
        merge_dict(options, app.builder.config.aafig_default_options)
        if format in format_map:
            options["format"] = format_map[format]
        else:
            logger.warn(
                'unsupported builder format "%s", please '
                "add a custom entry in aafig_format config "
                "option for this builder" % format
            )
            img.replace_self(nodes.literal_block(text, text))
            continue
        if options["format"] is None:
            img.replace_self(nodes.literal_block(text, text))
            continue
        try:
            fname, outfn, id, extra = render_aafigure(app, text, options)
        except AafigError as exc:
            logger.warn("aafigure error: " + str(exc))
            img.replace_self(nodes.literal_block(text, text))
            continue
        img["uri"] = fname
        # FIXME: find some way to avoid this hack in aafigure
        if extra:
            (width, height) = [x.split('"')[1] for x in extra.split()]
            if "width" not in img:
                img["width"] = width
            if "height" not in img:
                img["height"] = height


def render_aafigure(app, text, options):
    """
    Render an ASCII art figure into the requested format output file.
    """

    if aafigure is None:
        raise AafigError("aafigure module not installed")

    fname = get_basename(text, options)
    fname = "%s.%s" % (get_basename(text, options), options["format"])
    if app.builder.format == "html":
        # HTML
        imgpath = relative_uri(app.builder.env.docname, "_images")
        relfn = posixpath.join(imgpath, fname)
        outfn = path.join(app.builder.outdir, "_images", fname)
    else:
        # Non-HTML
        if app.builder.format != "latex":
            logger.warn(
                "aafig: the builder format %s is not officially "
                "supported, aafigure images could not work. "
                "Please report problems and working builder to "
                "avoid this warning inthe future" % app.builder.format
            )
        relfn = fname
        outfn = path.join(app.builder.outdir, fname)
    metadata_fname = "%s.aafig" % outfn

    try:
        if path.isfile(outfn):
            extra = None
            if options["format"].lower() == "svg":
                f = None
                try:
                    try:
                        f = open(metadata_fname, "r")
                        extra = f.read()
                    except Exception:
                        raise AafigError()
                finally:
                    if f is not None:
                        f.close()
            return relfn, outfn, id, extra
    except AafigError:
        pass

    ensuredir(path.dirname(outfn))

    try:
        (visitor, output) = aafigure.render(text, outfn, options)
        output.close()
    except aafigure.UnsupportedFormatError as e:
        raise AafigError(str(e))

    extra = None
    if options["format"].lower() == "svg":
        extra = visitor.get_size_attrs()
        f = open(metadata_fname, "w")
        f.write(extra)
        f.close()

    return relfn, outfn, id, extra


def setup(app):
    app.add_directive("aafig", AafigDirective)
    app.connect("doctree-read", render_aafig_images)
    app.add_config_value("aafig_format", DEFAULT_FORMATS, "html")
    app.add_config_value("aafig_default_options", dict(), "html")


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