added Surface._find_label_border_segments()

freesurfer_surface/__init__.py

@@ -63,9 +63,35 @@ def setlocale(temporary_locale):
 Vertex = collections.namedtuple('Vertex', ['right', 'anterior', 'superior'])
 
 
-class Triangle:
+class _LineSegment:
 
-    # pylint: disable=too-few-public-methods
+    _VERTEX_INDICES_TYPE = typing.Tuple[int]
+
+    _vertex_indices: _VERTEX_INDICES_TYPE
+
+    def __init__(self, vertex_indices: _VERTEX_INDICES_TYPE):
+        self.vertex_indices = vertex_indices
+
+    @property
+    def vertex_indices(self):
+        return self._vertex_indices
+
+    @vertex_indices.setter
+    def vertex_indices(self, indices: _VERTEX_INDICES_TYPE):
+        assert len(indices) == 2
+        self._vertex_indices = indices
+
+    def __eq__(self, other: '_Line') -> bool:
+        return self.vertex_indices == other.vertex_indices
+
+    def __hash__(self) -> int:
+        return hash(self._vertex_indices)
+
+    def __repr__(self) -> str:
+        return '_LineSegment(vertex_indices={})'.format(self.vertex_indices)
+
+
+class Triangle:
 
     _VERTEX_INDICES_TYPE = typing.Tuple[int]
 
@@ -278,3 +304,12 @@ class Surface:
     def add_vertex(self, vertex: Vertex) -> int:
         self.vertices.append(vertex)
         return len(self.vertices) - 1
+
+    def _find_label_border_segments(self, label: Label) -> typing.Iterator[_LineSegment]:
+        for triangle in self.triangles:
+            border_vertex_indices = tuple(filter(
+                lambda i: self.annotation.vertex_label_index[i] == label.index,
+                triangle.vertex_indices,
+            ))
+            if len(border_vertex_indices) == 2:
+                yield _LineSegment(border_vertex_indices)

tests/conftest.py

@@ -3,3 +3,4 @@ import os
 SUBJECTS_DIR = os.path.join(os.path.dirname(__file__), 'subjects')
 
 ANNOTATION_FILE_PATH = os.path.join(SUBJECTS_DIR, 'fabian', 'label', 'lh.aparc.annot')
+SURFACE_FILE_PATH = os.path.join(SUBJECTS_DIR, 'fabian', 'surf', 'lh.pial')

tests/test_surface.py

@@ -1,13 +1,11 @@
 import datetime
-import os
 
 import pytest
 
-from freesurfer_surface import setlocale, Vertex, Triangle, Annotation, Surface
+from freesurfer_surface import setlocale, Vertex, Triangle, _LineSegment, \
+                               Annotation, Surface
 
-from conftest import SUBJECTS_DIR
-
-SURFACE_FILE_PATH = os.path.join(SUBJECTS_DIR, 'fabian', 'surf', 'lh.pial')
+from conftest import ANNOTATION_FILE_PATH, SURFACE_FILE_PATH
 
 
 def test_read_triangular():
@@ -119,8 +117,7 @@ def test_write_triangular_same_locale(tmpdir):
 def test_load_annotation():
     surface = Surface.read_triangular(SURFACE_FILE_PATH)
     assert not surface.annotation
-    surface.load_annotation_file(os.path.join(SUBJECTS_DIR, 'fabian',
-                                              'label', 'lh.aparc.annot'))
+    surface.load_annotation_file(ANNOTATION_FILE_PATH)
     assert isinstance(surface.annotation, Annotation)
     assert len(surface.annotation.vertex_label_index) == 155622
     assert surface.annotation.vertex_label_index[0] == 5
@@ -135,3 +132,20 @@ def test_add_vertex():
     assert surface.add_vertex(Vertex(-3.0, 0.0, 4.0)) == 1
     assert len(surface.vertices) == 2
     assert surface.vertices[1].right == pytest.approx(-3.0)
+
+
+def test__find_label_border_segments():
+    surface = Surface.read_triangular(SURFACE_FILE_PATH)
+    surface.load_annotation_file(ANNOTATION_FILE_PATH)
+    precentral_label, = filter(lambda l: l.name == 'precentral',
+                               surface.annotation.labels.values())
+    # pylint: disable=protected-access
+    border_segments = set(surface._find_label_border_segments(precentral_label))
+    assert len(border_segments) == 417
+    assert _LineSegment((33450, 32065)) in border_segments
+    assert _LineSegment((33454, 33450)) in border_segments
+    for border_vertex_index in [33450, 33454, 32065]:
+        assert surface.annotation.vertex_label_index[border_vertex_index] == precentral_label.index
+        for other_vertex_index in [32064, 33449, 33455, 33449, 33455]:
+            assert _LineSegment((other_vertex_index, border_vertex_index)) not in border_segments
+            assert _LineSegment((border_vertex_index, other_vertex_index)) not in border_segments