Merge pull request #1508 from fonttools/svg-shapes

[svgLib] add support for importing shapes into paths

Lib/fontTools/svgLib/path/__init__.py

@@ -5,6 +5,7 @@ from fontTools.misc.py23 import *
 from fontTools.pens.transformPen import TransformPen
 from fontTools.misc import etree
 from .parser import parse_path
+from .shapes import PathBuilder
 
 
 __all__ = [tostr(s) for s in ("SVGPath", "parse_path")]
@@ -50,5 +51,10 @@ class SVGPath(object):
     def draw(self, pen):
         if self.transform:
             pen = TransformPen(pen, self.transform)
-        for el in self.root.findall(".//{http://www.w3.org/2000/svg}path[@d]"):
+        pb = PathBuilder()
-            parse_path(el.get("d"), pen)
+        # xpath | doesn't seem to reliable work so just walk it
+        for el in self.root.iter():
+            pb.add_path_from_element(el)
+        for path in pb.paths:
+            parse_path(path, pen)
+

Lib/fontTools/svgLib/path/shapes.py

@@ -0,0 +1,125 @@
+def _prefer_non_zero(*args):
+    for arg in args:
+        if arg != 0:
+            return arg
+    return 0.
+
+
+def _ntos(n):
+    # %f likes to add unnecessary 0's, %g isn't consistent about # decimals
+    return ('%.3f' % n).rstrip('0').rstrip('.')
+
+
+def _strip_xml_ns(tag):
+    # ElementTree API doesn't provide a way to ignore XML namespaces in tags
+    # so we here strip them ourselves: cf. https://bugs.python.org/issue18304
+    return tag.split('}', 1)[1] if '}' in tag else tag
+
+
+class PathBuilder(object):
+    def __init__(self):
+        self.paths = []
+
+    def _start_path(self, initial_path=''):
+        self.paths.append(initial_path)
+
+    def _end_path(self):
+        self._add('z')
+
+    def _add(self, path_snippet):
+        path = self.paths[-1]
+        if path:
+            path += ' ' + path_snippet
+        else:
+            path = path_snippet
+        self.paths[-1] = path
+
+    def _move(self, c, x, y):
+        self._add('%s%s,%s' % (c, _ntos(x), _ntos(y)))
+
+    def M(self, x, y):
+        self._move('M', x, y)
+
+    def m(self, x, y):
+        self._move('m', x, y)
+
+    def _arc(self, c, rx, ry, x, y, large_arc):
+        self._add('%s%s,%s 0 %d 1 %s,%s' % (c, _ntos(rx), _ntos(ry), large_arc,
+                                            _ntos(x), _ntos(y)))
+
+    def A(self, rx, ry, x, y, large_arc=0):
+        self._arc('A', rx, ry, x, y, large_arc)
+
+    def a(self, rx, ry, x, y, large_arc=0):
+        self._arc('a', rx, ry, x, y, large_arc)
+
+    def _vhline(self, c, x):
+        self._add('%s%s' % (c, _ntos(x)))
+
+    def H(self, x):
+        self._vhline('H', x)
+
+    def h(self, x):
+        self._vhline('h', x)
+
+    def V(self, y):
+        self._vhline('V', y)
+
+    def v(self, y):
+        self._vhline('v', y)
+
+    def _parse_rect(self, rect):
+        x = float(rect.attrib.get('x', 0))
+        y = float(rect.attrib.get('y', 0))
+        w = float(rect.attrib.get('width'))
+        h = float(rect.attrib.get('height'))
+        rx = float(rect.attrib.get('rx', 0))
+        ry = float(rect.attrib.get('ry', 0))
+
+        rx = _prefer_non_zero(rx, ry)
+        ry = _prefer_non_zero(ry, rx)
+        # TODO there are more rules for adjusting rx, ry
+
+        self._start_path()
+        self.M(x + rx, y)
+        self.H(x + w - rx)
+        if rx > 0:
+            self.A(rx, ry, x + w, y + ry)
+        self.V(y + h - ry)
+        if rx > 0:
+            self.A(rx, ry, x + w - rx, y + h)
+        self.H(x + rx)
+        if rx > 0:
+            self.A(rx, ry, x, y + h - ry)
+        self.V(y + ry)
+        if rx > 0:
+            self.A(rx, ry, x + rx, y)
+        self._end_path()
+
+    def _parse_path(self, path):
+        if 'd' in path.attrib:
+            self._start_path(initial_path=path.attrib['d'])
+
+    def _parse_polygon(self, poly):
+        if 'points' in poly.attrib:
+            self._start_path('M' + poly.attrib['points'])
+            self._end_path()
+
+    def _parse_circle(self, circle):
+        cx = float(circle.attrib.get('cx', 0))
+        cy = float(circle.attrib.get('cy', 0))
+        r = float(circle.attrib.get('r'))
+
+        # arc doesn't seem to like being a complete shape, draw two halves
+        self._start_path()
+        self.M(cx - r, cy)
+        self.A(r, r, cx + r, cy, large_arc=1)
+        self.A(r, r, cx - r, cy, large_arc=1)
+
+    def add_path_from_element(self, el):
+        tag = _strip_xml_ns(el.tag)
+        parse_fn = getattr(self, '_parse_%s' % tag.lower(), None)
+        if not callable(parse_fn):
+            return False
+        parse_fn(el)
+        return True

Tests/svgLib/path/shapes_test.py

@@ -0,0 +1,68 @@
+from __future__ import print_function, absolute_import, division
+
+from fontTools.misc.py23 import *
+from fontTools.pens.recordingPen import RecordingPen
+from fontTools.svgLib.path import shapes
+from fontTools.misc import etree
+import pytest
+
+
+@pytest.mark.parametrize(
+    "svg_xml, expected_path",
+    [
+        # path: direct passthrough
+        (
+          "<path d='I love kittens'/>",
+          "I love kittens"
+        ),
+        # path no @d
+        (
+          "<path duck='Mallard'/>",
+          None
+        ),
+        # rect: minimal valid example
+        (
+            "<rect width='1' height='1'/>",
+            "M0,0 H1 V1 H0 V0 z",
+        ),
+        # rect: sharp corners
+        (
+            "<rect x='10' y='11' width='17' height='11'/>",
+            "M10,11 H27 V22 H10 V11 z",
+        ),
+        # rect: round corners
+        (
+            "<rect x='9' y='9' width='11' height='7' rx='2'/>",
+            "M11,9 H18 A2,2 0 0 1 20,11 V14 A2,2 0 0 1 18,16 H11"
+            " A2,2 0 0 1 9,14 V11 A2,2 0 0 1 11,9 z",
+        ),
+        # polygon
+        (
+            "<polygon points='30,10 50,30 10,30'/>",
+            "M30,10 50,30 10,30 z"
+        ),
+        # circle, minimal valid example
+        (
+            "<circle r='1'/>",
+            "M-1,0 A1,1 0 1 1 1,0 A1,1 0 1 1 -1,0"
+        ),
+        # circle
+        (
+            "<circle cx='600' cy='200' r='100'/>",
+            "M500,200 A100,100 0 1 1 700,200 A100,100 0 1 1 500,200"
+        ),
+        # circle, decimal positioning
+        (
+            "<circle cx='12' cy='6.5' r='1.5'></circle>",
+            "M10.5,6.5 A1.5,1.5 0 1 1 13.5,6.5 A1.5,1.5 0 1 1 10.5,6.5"
+        )
+    ]
+)
+def test_el_to_path(svg_xml, expected_path):
+    pb = shapes.PathBuilder()
+    pb.add_path_from_element(etree.fromstring(svg_xml))
+    if expected_path:
+        expected = [expected_path]
+    else:
+        expected = []
+    assert pb.paths == expected