Initial implementation

.gitignore

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+__pycache__/
+*.py[cod]
+vectordraw_xblock.egg-info/

setup.py

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+"""Setup for vectordraw XBlock."""
+
+import os
+from setuptools import setup
+
+
+def package_data(pkg, roots):
+    """Generic function to find package_data.
+
+    All of the files under each of the `roots` will be declared as package
+    data for package `pkg`.
+
+    """
+    data = []
+    for root in roots:
+        for dirname, _, files in os.walk(os.path.join(pkg, root)):
+            for fname in files:
+                data.append(os.path.relpath(os.path.join(dirname, fname), pkg))
+
+    return {pkg: data}
+
+
+setup(
+    name='vectordraw-xblock',
+    version='0.1',
+    description='vectordraw XBlock',   # TODO: write a better description.
+    packages=[
+        'vectordraw',
+    ],
+    install_requires=[
+        'XBlock',
+    ],
+    entry_points={
+        'xblock.v1': [
+            'vectordraw = vectordraw:VectorDrawXBlock',
+        ]
+    },
+    package_data=package_data("vectordraw", ["static", "public"]),
+)

vectordraw/__init__.py

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+from .vectordraw import VectorDrawXBlock

vectordraw/grader.py

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+import inspect
+import json
+import logging
+import math
+
+
+log = logging.getLogger(__name__)
+
+
+## Built-in check functions
+
+def _errmsg(default_message, check, vectors):
+    template = check.get('errmsg', default_message)
+    vec = vectors[check['vector']]
+    return template.format(name=vec.name,
+                           tail_x=vec.tail.x,
+                           tail_y=vec.tail.y,
+                           tip_x=vec.tip.x,
+                           tip_y=vec.tip.y,
+                           length=vec.length,
+                           angle=vec.angle)
+
+def _errmsg_point(default_message, check, point):
+    template = check.get('errmsg', default_message)
+    return template.format(name=check['point'], x=point.x, y=point.y)
+
+def check_presence(check, vectors):
+    if check['vector'] not in vectors:
+        errmsg = check.get('errmsg', 'You need to use the {name} vector.')
+        return errmsg.format(name=check['vector'])
+
+def check_tail(check, vectors):
+    vec = vectors[check['vector']]
+    tolerance = check.get('tolerance', 1.0)
+    expected = check['expected']
+    dist = math.hypot(expected[0] - vec.tail.x, expected[1] - vec.tail.y)
+    if dist > tolerance:
+        return _errmsg('Vector {name} does not start at correct point.', check, vectors)
+
+def check_tip(check, vectors):
+    vec = vectors[check['vector']]
+    tolerance = check.get('tolerance', 1.0)
+    expected = check['expected']
+    dist = math.hypot(expected[0] - vec.tip.x, expected[1] - vec.tip.y)
+    if dist > tolerance:
+        return _errmsg('Vector {name} does not end at correct point.', check, vectors)
+
+def _check_coordinate(check, coord):
+    tolerance = check.get('tolerance', 1.0)
+    expected = check['expected']
+    return abs(expected - coord) > tolerance
+
+def check_tail_x(check, vectors):
+    vec = vectors[check['vector']]
+    if _check_coordinate(check, vec.tail.x):
+        return _errmsg('Vector {name} does not start at correct point.', check, vectors)
+
+def check_tail_y(check, vectors):
+    vec = vectors[check['vector']]
+    if _check_coordinate(check, vec.tail.y):
+        return _errmsg('Vector {name} does not start at correct point.', check, vectors)
+
+def check_tip_x(check, vectors):
+    vec = vectors[check['vector']]
+    if _check_coordinate(check, vec.tip.x):
+        return _errmsg('Vector {name} does not end at correct point.', check, vectors)
+
+def check_tip_y(check, vectors):
+    vec = vectors[check['vector']]
+    if _check_coordinate(check, vec.tip.y):
+        return _errmsg('Vector {name} does not end at correct point.', check, vectors)
+
+def _coord_delta(expected, actual):
+    if expected == '_':
+        return 0
+    else:
+        return expected - actual
+
+def _coords_within_tolerance(vec, expected, tolerance):
+    for expected_coords, vec_coords in ([expected[0], vec.tail], [expected[1], vec.tip]):
+        delta_x = _coord_delta(expected_coords[0], vec_coords.x)
+        delta_y = _coord_delta(expected_coords[1], vec_coords.y)
+        if math.hypot(delta_x, delta_y) > tolerance:
+            return False
+    return True
+
+def check_coords(check, vectors):
+    vec = vectors[check['vector']]
+    expected = check['expected']
+    tolerance = check.get('tolerance', 1.0)
+    if not _coords_within_tolerance(vec, expected, tolerance):
+        return _errmsg('Vector {name} coordinates are not correct.', check, vectors)
+
+def check_segment_coords(check, vectors):
+    vec = vectors[check['vector']]
+    expected = check['expected']
+    tolerance = check.get('tolerance', 1.0)
+    if not (_coords_within_tolerance(vec, expected, tolerance) or
+            _coords_within_tolerance(vec.opposite(), expected, tolerance)):
+        return _errmsg('Segment {name} coordinates are not correct.', check, vectors)
+
+def check_length(check, vectors):
+    vec = vectors[check['vector']]
+    tolerance = check.get('tolerance', 1.0)
+    if abs(vec.length - check['expected']) > tolerance:
+        return _errmsg('The length of {name} is incorrect. Your length: {length:.1f}', check, vectors)
+
+def _angle_within_tolerance(vec, expected, tolerance):
+    # Calculate angle between vec and identity vector with expected angle
+    # using the formula:
+    # angle = acos((A . B) / len(A)*len(B))
+    x = vec.tip.x - vec.tail.x
+    y = vec.tip.y - vec.tail.y
+    dot_product = x * math.cos(expected) + y * math.sin(expected)
+    angle = math.degrees(math.acos(dot_product / vec.length))
+    return abs(angle) <= tolerance
+
+def check_angle(check, vectors):
+    vec = vectors[check['vector']]
+    tolerance = check.get('tolerance', 2.0)
+    expected = math.radians(check['expected'])
+    if not _angle_within_tolerance(vec, expected, tolerance):
+        return _errmsg('The angle of {name} is incorrect. Your angle: {angle:.1f}', check, vectors)
+
+def check_segment_angle(check, vectors):
+    # Segments are not directed, so we must check the angle between the segment and
+    # the vector that represents it, as well as its opposite vector.
+    vec = vectors[check['vector']]
+    tolerance = check.get('tolerance', 2.0)
+    expected = math.radians(check['expected'])
+    if not (_angle_within_tolerance(vec, expected, tolerance) or
+            _angle_within_tolerance(vec.opposite(), expected, tolerance)):
+        return _errmsg('The angle of {name} is incorrect. Your angle: {angle:.1f}', check, vectors)
+
+def _dist_line_point(line, point):
+    # Return the distance between the given line and point.  The line is passed in as a Vector
+    # instance, the point as a Point instance.
+    direction_x = line.tip.x - line.tail.x
+    direction_y = line.tip.y - line.tail.y
+    determinant = (point.x - line.tail.x) * direction_y - (point.y - line.tail.y) * direction_x
+    return abs(determinant) / math.hypot(direction_x, direction_y)
+
+def check_points_on_line(check, vectors):
+    line = vectors[check['vector']]
+    tolerance = check.get('tolerance', 1.0)
+    points = check.get('expected')
+    for point in points:
+        point = Point(point[0], point[1])
+        if _dist_line_point(line, point) > tolerance:
+            return _errmsg('The line {name} does not pass through the correct points.', check, vectors)
+
+def check_point_coords(check, points):
+    point = points[check['point']]
+    tolerance = check.get('tolerance', 1.0)
+    expected = check.get('expected')
+    dist = math.hypot(expected[0] - point.x, expected[1] - point.y)
+    if dist > tolerance:
+        return _errmsg_point('Point {name} is not at the correct location.', check, point)
+
+class Point(object):
+    def __init__(self, x, y):
+        self.x = x
+        self.y = y
+
+class Vector(object):
+    def __init__(self, name, x1, y1, x2, y2):
+        self.name = name
+        self.tail = Point(x1, y1)
+        self.tip = Point(x2, y2)
+        self.length = math.hypot(x2 - x1, y2 - y1)
+        angle = math.degrees(math.atan2(y2 - y1, x2 - x1))
+        if angle < 0:
+            angle += 360
+        self.angle = angle
+
+    def opposite(self):
+        return Vector(self.name, self.tip.x, self.tip.y, self.tail.x, self.tail.y)
+
+class Grader(object):
+    check_registry = {
+        'presence': check_presence,
+        'tail': check_tail,
+        'tip': check_tip,
+        'tail_x': check_tail_x,
+        'tail_y': check_tail_y,
+        'tip_x': check_tip_x,
+        'tip_y': check_tip_y,
+        'coords': check_coords,
+        'length': check_length,
+        'angle': check_angle,
+        'segment_angle': check_segment_angle,
+        'segment_coords': check_segment_coords,
+        'points_on_line': check_points_on_line,
+        'point_coords': check_point_coords,
+    }
+
+    def __init__(self, success_message='Test passed', custom_checks=None):
+        self.success_message = success_message
+        if custom_checks:
+            self.check_registry.update(custom_checks)
+
+    def grade(self, answer):
+        check_data = dict(
+            vectors=self._get_vectors(answer),
+            points=self._get_points(answer),
+        )
+        for check in answer['checks']:
+            check_data['check'] = check
+            check_fn = self.check_registry[check['check']]
+            args = [check_data[arg] for arg in inspect.getargspec(check_fn).args]
+            result = check_fn(*args)
+            if result:
+                return {'ok': False, 'msg': result}
+        return {'ok': True, 'msg': self.success_message}
+
+    def cfn(self, e, ans):
+        answer = json.loads(json.loads(ans)['answer'])
+        return self.grade(answer)
+
+    def _get_vectors(self, answer):
+        vectors = {}
+        for name, props in answer['vectors'].iteritems():
+            tail = props['tail']
+            tip = props['tip']
+            vectors[name] = Vector(name, tail[0], tail[1], tip[0], tip[1])
+        return vectors
+
+    def _get_points(self, answer):
+        return {name: Point(*coords) for name, coords in answer['points'].iteritems()}

vectordraw/static/css/vectordraw.css

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+/* CSS for VectorDrawXBlock */
+
+.vectordraw_block,
+.vectordraw_block #vectordraw {
+    display: inline-block;
+}
+
+.vectordraw_block .vectordraw-description,
+.vectordraw_block #vectordraw,
+.vectordraw_block .vectordraw-status {
+    margin-bottom: 1.5em;
+}
+
+.vectordraw_block .jxgboard {
+    float: left;
+    border: 2px solid #1f628d;
+}
+
+.vectordraw_block .jxgboard .JXGtext {
+    pointer-events: none;  /* prevents cursor from turning into caret when over a label */
+}
+
+.vectordraw_block .menu {
+    float: left;
+    width: 160px;
+    margin-left: 15px;
+}
+
+.vectordraw_block .menu .controls {
+    margin-bottom: 20px;
+    font-size: 0;
+}
+
+.vectordraw_block .menu .controls select {
+    width: 160px;
+    margin-bottom: 8px;
+    font-size: 18px;
+}
+
+.vectordraw_block .menu .controls button {
+    display: inline-block;
+    background-color: #3498db;
+    border-radius: 5px;
+    box-shadow: 0 1px 3px #666;
+    color: #1f628d;
+    font-size: 14px;
+    padding: 5px 10px 5px 10px;
+    margin: 4px 0;
+    border: 2px solid #1f628d;
+    text-decoration: none;
+    width: 160px;
+}
+
+.vectordraw_block .menu .controls button:hover {
+    background: #3cb0fd;
+    background-image: -webkit-linear-gradient(top, #3cb0fd, #3498db);
+    background-image: -moz-linear-gradient(top, #3cb0fd, #3498db);
+    background-image: -ms-linear-gradient(top, #3cb0fd, #3498db);
+    background-image: -o-linear-gradient(top, #3cb0fd, #3498db);
+    background-image: linear-gradient(to bottom, #3cb0fd, #3498db);
+    text-decoration: none;
+}
+
+vectordraw_block .menu .controls button.undo,
+vectordraw_block .menu .controls button.redo {
+    width: 78px;
+}
+
+.vectordraw_block .menu .controls button.undo {
+    margin-right: 4px;
+}
+
+.vectordraw_block .menu .vector-properties {
+    padding: 10px;
+    border: 1px solid #1f628d;
+    font-size: 16px;
+    line-height: 1.25;
+}
+
+.vectordraw_block .menu .vector-properties h3 {
+    font-size: 16px;
+    margin: 0 0 5px;
+}
+
+.vectordraw_block .menu .vector-properties .vector-prop-bold {
+    font-weight: bold;
+}
+
+.vectordraw_block .menu .vector-prop-slope {
+    display: none;
+}
+
+.vectordraw_block .action button {
+    height: 40px;
+    margin-right: 10px;
+    font-weight: 600;
+    text-transform: uppercase;
+}
+
+.vectordraw_block .vectordraw-status {
+    display: inline-block;
+    width: 100%;
+}
+
+.vectordraw_block .checkmark-correct {
+    font-size: 22pt;
+    color: #629b2b;
+}
+
+.vectordraw_block .checkmark-incorrect {
+    font-size: 22pt;
+    color: #ff0000;
+}