rewrite outline extension

lib/extensions/outline.py

@@ -3,26 +3,37 @@
 # Copyright (c) 2010 Authors
 # Licensed under the GNU GPL version 3.0 or later.  See the file LICENSE for details.
 
-import inkex
-from shapely import concave_hull
-from shapely.geometry import LineString, MultiPolygon
+from inkex import Boolean, Path, errormsg
+from shapely import offset_curve
+from shapely.geometry import LineString, MultiPolygon, Polygon
 
 from ..i18n import _
+from ..svg import PIXELS_PER_MM
 from ..svg.tags import SVG_PATH_TAG
+from ..utils.geometry import ensure_multi_line_string
+from ..utils.smoothing import smooth_path
 from .base import InkstitchExtension
 
 
 class Outline(InkstitchExtension):
     def __init__(self, *args, **kwargs):
         InkstitchExtension.__init__(self, *args, **kwargs)
-        self.arg_parser.add_argument("-r", "--ratio", type=float, default=0.0, dest="ratio")
-        self.arg_parser.add_argument("-a", "--allow-holes", type=inkex.Boolean, default=False, dest="allow_holes")
+        self.arg_parser.add_argument("-k", "--keep-original", type=Boolean, default=False, dest="keep_original")
+        self.arg_parser.add_argument("-b", "--buffer", type=float, default=0.001, dest="buffer")
+        self.arg_parser.add_argument("-s", "--smoothness", type=float, default=0.3, dest="smoothness")
+        self.arg_parser.add_argument("-t", "--threshold", type=float, default=10.0, dest="threshold")
+        self.arg_parser.add_argument("-i", "--inset", type=float, default=0.001, dest="inset")
 
     def effect(self):
         if not self.svg.selection:
-            inkex.errormsg(_("Please select one or more shapes to convert to their outline."))
+            errormsg(_("Please select one or more shapes to convert to their outline."))
             return
 
+        self.threshold = self.options.threshold * PIXELS_PER_MM
+        self.shape_buffer = max(self.options.buffer * PIXELS_PER_MM, 0.001)
+        self.smoothness = self.options.smoothness * PIXELS_PER_MM
+        self.inset = self.options.inset * PIXELS_PER_MM
+
         for element in self.svg.selection:
             self.element_to_outline(element)
 
@@ -32,19 +43,27 @@ class Outline(InkstitchExtension):
                 self.element_to_outline(element)
             return
 
-        path = element.get_path()
-        path = path.end_points
-        hull = concave_hull(LineString(path), ratio=self.options.ratio, allow_holes=self.options.allow_holes)
-        if isinstance(hull, LineString):
-            return
-
-        if not isinstance(hull, MultiPolygon):
-            hull = MultiPolygon([hull])
         d = ''
-        for geom in hull.geoms:
-            d += 'M '
-            for x, y in geom.exterior.coords:
-                d += f'{x}, {y} '
-            d += "Z"
+        transform = element.composed_transform()
+        path = element.get_path().transform(transform).break_apart()
+        for subpath in path:
+            points = subpath.end_points
+            shape = LineString(points).buffer(self.shape_buffer)
+            outline = ensure_multi_line_string(offset_curve(shape, -self.inset))
 
-        element.set('d', d)
+            interiors = []
+            for interior in outline.geoms:
+                if Polygon(interior).area < self.threshold:
+                    continue
+                interior_path = smooth_path(interior.coords, self.smoothness)
+                if len(interior_path) > 2:
+                    interiors.append(Polygon(interior_path))
+            outline = MultiPolygon(interiors)
+
+            for geom in outline.geoms:
+                d += str(Path(geom.exterior.coords).transform(-transform))
+        if self.options.keep_original:
+            element.duplicate()
+            element.set('d', d)
+        else:
+            element.set('d', d)

templates/outline.xml

@@ -11,8 +11,21 @@
             </submenu>
         </effects-menu>
     </effect>
-    <param name="ratio" type="float" appearance="full" gui-text="Ratio" precision="2" min="0" max="1">0</param>
-    <param name="allow-holes" type="boolean" gui-text="Allow Holes">false</param>
+    <param name="keep-original" type="boolean" gui-text="Keep original element(s)">false</param>
+    <spacer />
+    <separator />
+    <spacer />
+    <param name="threshold" type="float" appearance="full" precision="2" min="0" max="100"
+           gui-text="Threshold (mm)" gui-description="Removes smaller shape areas than that">10</param>
+    <param name="buffer" type="float" appearance="full" precision="3" min="0.001" max="1"
+           gui-text="Buffer (mm)" gui-description="Enlarge strokes by this amount">0.001</param>
+    <param name="smoothness" type="float" appearance="full" precision="2" min="0.01" max="5"
+           gui-text="Smoothness (mm)" gui-description="Smooth path by this amount">0.3</param>
+    <spacer />
+    <separator />
+    <spacer />
+    <param name="inset" type="float" appearance="full" precision="2" min="0.01" max="5"
+           gui-text="Inset (mm)" gui-description="Counteract the buffer effect">0.001</param>
     <script>
         {{ command_tag | safe }}
     </script>