xref: /aosp_15_r20/external/fonttools/Lib/fontTools/svgLib/path/shapes.py (revision e1fe3e4ad2793916b15cccdc4a7da52a7e1dd0e9) 
1import re
2
3
4def _prefer_non_zero(*args):
5    for arg in args:
6        if arg != 0:
7            return arg
8    return 0.0
9
10
11def _ntos(n):
12    # %f likes to add unnecessary 0's, %g isn't consistent about # decimals
13    return ("%.3f" % n).rstrip("0").rstrip(".")
14
15
16def _strip_xml_ns(tag):
17    # ElementTree API doesn't provide a way to ignore XML namespaces in tags
18    # so we here strip them ourselves: cf. https://bugs.python.org/issue18304
19    return tag.split("}", 1)[1] if "}" in tag else tag
20
21
22def _transform(raw_value):
23    # TODO assumes a 'matrix' transform.
24    # No other transform functions are supported at the moment.
25    # https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/transform
26    # start simple: if you aren't exactly matrix(...) then no love
27    match = re.match(r"matrix\((.*)\)", raw_value)
28    if not match:
29        raise NotImplementedError
30    matrix = tuple(float(p) for p in re.split(r"\s+|,", match.group(1)))
31    if len(matrix) != 6:
32        raise ValueError("wrong # of terms in %s" % raw_value)
33    return matrix
34
35
36class PathBuilder(object):
37    def __init__(self):
38        self.paths = []
39        self.transforms = []
40
41    def _start_path(self, initial_path=""):
42        self.paths.append(initial_path)
43        self.transforms.append(None)
44
45    def _end_path(self):
46        self._add("z")
47
48    def _add(self, path_snippet):
49        path = self.paths[-1]
50        if path:
51            path += " " + path_snippet
52        else:
53            path = path_snippet
54        self.paths[-1] = path
55
56    def _move(self, c, x, y):
57        self._add("%s%s,%s" % (c, _ntos(x), _ntos(y)))
58
59    def M(self, x, y):
60        self._move("M", x, y)
61
62    def m(self, x, y):
63        self._move("m", x, y)
64
65    def _arc(self, c, rx, ry, x, y, large_arc):
66        self._add(
67            "%s%s,%s 0 %d 1 %s,%s"
68            % (c, _ntos(rx), _ntos(ry), large_arc, _ntos(x), _ntos(y))
69        )
70
71    def A(self, rx, ry, x, y, large_arc=0):
72        self._arc("A", rx, ry, x, y, large_arc)
73
74    def a(self, rx, ry, x, y, large_arc=0):
75        self._arc("a", rx, ry, x, y, large_arc)
76
77    def _vhline(self, c, x):
78        self._add("%s%s" % (c, _ntos(x)))
79
80    def H(self, x):
81        self._vhline("H", x)
82
83    def h(self, x):
84        self._vhline("h", x)
85
86    def V(self, y):
87        self._vhline("V", y)
88
89    def v(self, y):
90        self._vhline("v", y)
91
92    def _line(self, c, x, y):
93        self._add("%s%s,%s" % (c, _ntos(x), _ntos(y)))
94
95    def L(self, x, y):
96        self._line("L", x, y)
97
98    def l(self, x, y):
99        self._line("l", x, y)
100
101    def _parse_line(self, line):
102        x1 = float(line.attrib.get("x1", 0))
103        y1 = float(line.attrib.get("y1", 0))
104        x2 = float(line.attrib.get("x2", 0))
105        y2 = float(line.attrib.get("y2", 0))
106
107        self._start_path()
108        self.M(x1, y1)
109        self.L(x2, y2)
110
111    def _parse_rect(self, rect):
112        x = float(rect.attrib.get("x", 0))
113        y = float(rect.attrib.get("y", 0))
114        w = float(rect.attrib.get("width"))
115        h = float(rect.attrib.get("height"))
116        rx = float(rect.attrib.get("rx", 0))
117        ry = float(rect.attrib.get("ry", 0))
118
119        rx = _prefer_non_zero(rx, ry)
120        ry = _prefer_non_zero(ry, rx)
121        # TODO there are more rules for adjusting rx, ry
122
123        self._start_path()
124        self.M(x + rx, y)
125        self.H(x + w - rx)
126        if rx > 0:
127            self.A(rx, ry, x + w, y + ry)
128        self.V(y + h - ry)
129        if rx > 0:
130            self.A(rx, ry, x + w - rx, y + h)
131        self.H(x + rx)
132        if rx > 0:
133            self.A(rx, ry, x, y + h - ry)
134        self.V(y + ry)
135        if rx > 0:
136            self.A(rx, ry, x + rx, y)
137        self._end_path()
138
139    def _parse_path(self, path):
140        if "d" in path.attrib:
141            self._start_path(initial_path=path.attrib["d"])
142
143    def _parse_polygon(self, poly):
144        if "points" in poly.attrib:
145            self._start_path("M" + poly.attrib["points"])
146            self._end_path()
147
148    def _parse_polyline(self, poly):
149        if "points" in poly.attrib:
150            self._start_path("M" + poly.attrib["points"])
151
152    def _parse_circle(self, circle):
153        cx = float(circle.attrib.get("cx", 0))
154        cy = float(circle.attrib.get("cy", 0))
155        r = float(circle.attrib.get("r"))
156
157        # arc doesn't seem to like being a complete shape, draw two halves
158        self._start_path()
159        self.M(cx - r, cy)
160        self.A(r, r, cx + r, cy, large_arc=1)
161        self.A(r, r, cx - r, cy, large_arc=1)
162
163    def _parse_ellipse(self, ellipse):
164        cx = float(ellipse.attrib.get("cx", 0))
165        cy = float(ellipse.attrib.get("cy", 0))
166        rx = float(ellipse.attrib.get("rx"))
167        ry = float(ellipse.attrib.get("ry"))
168
169        # arc doesn't seem to like being a complete shape, draw two halves
170        self._start_path()
171        self.M(cx - rx, cy)
172        self.A(rx, ry, cx + rx, cy, large_arc=1)
173        self.A(rx, ry, cx - rx, cy, large_arc=1)
174
175    def add_path_from_element(self, el):
176        tag = _strip_xml_ns(el.tag)
177        parse_fn = getattr(self, "_parse_%s" % tag.lower(), None)
178        if not callable(parse_fn):
179            return False
180        parse_fn(el)
181        if "transform" in el.attrib:
182            self.transforms[-1] = _transform(el.attrib["transform"])
183        return True
184