1 files changed, 20 insertions, 23 deletions
diff --git a/gerbonara/layers.py b/gerbonara/layers.py
index e200e62..f98adee 100644
--- a/gerbonara/layers.py
+++ b/gerbonara/layers.py
@@ -39,6 +39,7 @@ from .cam import FileSettings, LazyCamFile
 from .layer_rules import MATCH_RULES
 from .utils import sum_bounds, setup_svg, MM, Tag, convex_hull
 from . import graphic_objects as go
+from . import apertures as ap
 from . import graphic_primitives as gp
 
 
@@ -273,7 +274,7 @@ def _layername_autoguesser(fn):
     elif re.search('film', fn):
         use = 'copper'
 
-    elif re.search('out(line)?|board.?geometry', fn):
+    elif re.search('out(line)?|board.?geom(etry)?', fn):
         use = 'outline'
         side = 'mechanical'
 
@@ -303,6 +304,9 @@ def _sort_layername(val):
     assert side.startswith('inner_')
     return int(side[len('inner_'):])
 
+def convex_hull_to_lines(points, unit=MM):
+    for (x1, y1), (x2, y2) in zip(points, points[1:] + points):
+        yield go.Line(x1, y1, x2, y2, aperture=ap.CircleAperture(unit(0.1, MM), unit=unit), unit=unit)
 
 class LayerStack:
     """ :py:class:`LayerStack` represents a set of Gerber files that describe different layers of the same board.
@@ -949,7 +953,7 @@ class LayerStack:
                 id=f'l-mechanical-outline', **stroke_attrs, **inkscape_attrs(f'outline'),
                 transform=layer_transform))
 
-        sc_y, tl_y = -1, (bounds[0][1] + bounds[1][1])
+        sc_y, tl_y = 1, 0
         if side == 'bottom':
             sc_x, tl_x = -1, (bounds[0][0] + bounds[1][0])
         else:
@@ -1184,22 +1188,6 @@ class LayerStack:
             polys.append(' '.join(poly.path_d()) + ' Z')
         return ' '.join(polys)
 
-    def outline_convex_hull(self, tol=0.01, unit=MM):
-        points = []
-        for obj in self.outline.instance.objects:
-            if isinstance(obj, go.Line):
-                line = obj.as_primitive(unit)
-                points.append((line.x1, line.y1))
-                points.append((line.x2, line.y2))
-
-            elif isinstance(obj, go.Arc):
-                for obj in obj.approximate(tol, unit):
-                    line = obj.as_primitive(unit)
-                    points.append((line.x1, line.y1))
-                    points.append((line.x2, line.y2))
-
-        return convex_hull(points)
-        
     def outline_polygons(self, tol=0.01, unit=MM):
         """ Iterator yielding this boards outline as a list of ordered :py:class:`~.graphic_objects.Arc` and
         :py:class:`~.graphic_objects.Line` objects. This method first sorts all lines and arcs on the outline layer into
@@ -1214,6 +1202,14 @@ class LayerStack:
         :param tol: :py:obj:`float` setting the tolerance below which two points are considered equal
         :param unit: :py:class:`.LengthUnit` or str (``'mm'`` or ``'inch'``). SVG document unit. Default: mm
         """
+
+        if not self.outline:
+            warnings.warn("Board has no outline layer, or the outline layer could not be identified by file name. Using the copper layers' convex hull instead.")
+            points = sum((layer.instance.convex_hull(tol, unit) for (_side, _use), layer in self.copper_layers), start=[])
+            yield list(convex_hull_to_lines(convex_hull(points), unit))
+            return
+
+        maybe_allegro_hint = '' if self.generator != 'allegro' else ' This file looks like it was generated by Allegro/OrCAD. These tools produce quite mal-formed gerbers, and often export text on the outline layer. If you generated this file yourself, maybe try twiddling with the export settings.'
         polygons = []
         lines = [ obj.as_primitive(unit) for obj in self.outline.instance.objects if isinstance(obj, (go.Line, go.Arc)) ]
 
@@ -1242,13 +1238,14 @@ class LayerStack:
                 j = 0 if d1 < d2 else 1
 
                 if (nearest, j) in joins and joins[(nearest, j)] != (cur, i):
-                    warnings.warn(f'Three-way intersection on outline layer at: {(nearest, j)}; {(cur, i)}; and {joins[(nearest, j)]}. Falling back to returning the convex hull of the outline layer.')
-                    return self.outline_convex_hull(tol, unit)
+                    warnings.warn(f'Three-way intersection on outline layer at: {(nearest, j)}; {(cur, i)}; and {joins[(nearest, j)]}. Falling back to returning the convex hull of the outline layer.{maybe_allegro_hint}')
+                    yield list(convex_hull_to_lines(self.outline.instance.convex_hull(tol, unit), unit))
+                    return
 
                 if (cur, i) in joins and joins[(cur, i)] != (nearest, j):
-                    warnings.warn(f'three-way intersection on outline layer at: {(nearest, j)}; {(cur, i)}; and {joins[(nearest, j)]}. Falling back to returning the convex hull of the outline layer.')
-                    return self.outline_convex_hull(tol, unit)
-
+                    warnings.warn(f'Three-way intersection on outline layer at: {(nearest, j)}; {(cur, i)}; and {joins[(nearest, j)]}. Falling back to returning the convex hull of the outline layer.{maybe_allegro_hint}')
+                    yield list(convex_hull_to_lines(self.outline.instance.convex_hull(tol, unit), unit))
+                    return
 
                 joins[(cur, i)] = (nearest, j)
                 joins[(nearest, j)] = (cur, i)