proto2prod.py

import json
import re


def path_strings_from_svg(svg):
    return re.findall(r'(?<=d=")[^"]+(?=")', svg)


def points_from_path(path):
    # Numbers are identified with a regex based on the SVG path data 'number' BNF
    numbers = re.findall(r"([-+]?(((\d*\.\d+|\d+\.)([eE][-+]?\d+)?|\d+[eE][-+]?\d+)|\d+))", path)
    numbers = [float(n[0]) for n in numbers]

    assert len(numbers) % 2 == 0, "An odd number of values was found while parsing a path"

    xvals = [n for (i, n) in enumerate(numbers) if i % 2 == 0]
    yvals = [n for (i, n) in enumerate(numbers) if i % 2 == 1]
    points = [[x, y] for (x, y) in zip(xvals, yvals, strict=False)]

    return points


def delta_decode_spline_points(points):
    i = 0
    while i + 3 < len(points):
        for d in [0, 1]:
            points[i + 1][d] += points[i][d]
            points[i + 2][d] += points[i][d]
            points[i + 3][d] += points[i][d]
        i += 3

    return points


def round_points(points):
    for p in points:
        for d in [0, 1]:
            p[d] = round(p[d], 2)

    return points


def parse_svg(svg):
    paths = path_strings_from_svg(svg)
    paths = [points_from_path(path) for path in paths]
    paths = [delta_decode_spline_points(path) for path in paths]
    paths = [round_points(path) for path in paths]
    return paths


def convert_ans_dict(ans_dict, xrange=None, yrange=None, width=800, height=480):
    if xrange is None:
        xrange = [-2.614, 2.608]
    if yrange is None:
        yrange = [-3.207, 3.193]
    svg = ans_dict["answer"]
    paths = parse_svg(svg)

    gradeable_dict = {
        "apiVersion": "0.1",
        "meta": {
            "config": {
                "width": width,
                "height": height,
                "xrange": xrange,
                "yrange": yrange,
                "xscale": "linear",
                "yscale": "linear",
                "plugins": [{"type": "freeform", "id": "f"}],
            }
        },
        "data": {"f": [{"spline": points} for points in paths]},
    }

    new_ans_dict = ans_dict.copy()
    new_ans_dict["answer"] = json.dumps(gradeable_dict)

    return new_ans_dict