Add selection to knockdown fill extension (#3526)

1 files changed, 106 insertions, 0 deletions

diff --git a/lib/extensions/knockdown_fill.py b/lib/extensions/knockdown_fill.py
new file mode 100644
index 00000000..35459016
--- /dev/null
+++ b/lib/extensions/knockdown_fill.py
@@ -0,0 +1,106 @@
+# Authors: see git history
+#
+# Copyright (c) 2025 Authors
+# Licensed under the GNU GPL version 3.0 or later.  See the file LICENSE for details.
+
+from inkex import Boolean, Path, PathElement
+from shapely import union_all
+from shapely.geometry import LineString, Polygon
+
+from ..stitches.ripple_stitch import ripple_stitch
+from ..svg import PIXELS_PER_MM, get_correction_transform
+from ..utils.geometry import ensure_multi_polygon
+from .base import InkstitchExtension
+
+
+class KnockdownFill(InkstitchExtension):
+    '''
+    This extension generates a shape around all selected shapes and inserts it into the document
+    '''
+    def __init__(self, *args, **kwargs):
+        InkstitchExtension.__init__(self, *args, **kwargs)
+        self.arg_parser.add_argument("--notebook")
+        self.arg_parser.add_argument("-k", "--keep-holes", type=Boolean, default=True, dest="keep_holes")
+        self.arg_parser.add_argument("-o", "--offset", type=float, default=0, dest="offset")
+        self.arg_parser.add_argument("-j", "--join-style", type=str, default="1", dest="join_style")
+        self.arg_parser.add_argument("-m", "--mitre-limit", type=float, default=5.0, dest="mitre_limit")
+        # TODO: Layer options: underlay, row spacing, angle
+
+    def effect(self):
+        if not self.get_elements():
+            return
+
+        polygons = []
+        for element in self.elements:
+            if element.name == "FillStitch":
+                # take expand value into account
+                shape = element.shrink_or_grow_shape(element.shape, element.expand)
+                # MultiPolygon
+                for polygon in shape.geoms:
+                    polygons.append(polygon)
+            elif element.name == "SatinColumn":
+                # plot points on rails, so we get the actual satin size (including pull compensation)
+                rail_pairs = zip(*element.plot_points_on_rails(
+                    0.3,
+                    element.pull_compensation_px,
+                    element.pull_compensation_percent / 100)
+                )
+                rails = []
+                for rail in rail_pairs:
+                    rails.append(LineString(rail))
+                polygon = Polygon(list(rails[0].coords) + list(rails[1].reverse().coords)).buffer(0)
+                polygons.append(polygon)
+            elif element.name == "Stroke":
+                if element.stroke_method == 'ripple_stitch':
+                    # for ripples this is going to be a bit complicated, so let's follow the stitch plan
+                    stitches = ripple_stitch(element)
+                    linestring = LineString(stitches)
+                    polygons.append(linestring.buffer(0.15 * PIXELS_PER_MM, cap_style='flat'))
+                elif element.stroke_method == 'zigzag_stitch':
+                    # zigzag stitch depends on the width of the stroke and pull compensation settings
+                    polygons.append(element.as_multi_line_string().buffer((element.stroke_width + element.pull_compensation) / 2, cap_style='flat'))
+                else:
+                    polygons.append(element.as_multi_line_string().buffer(0.15 * PIXELS_PER_MM, cap_style='flat'))
+        combined_shape = union_all(polygons)
+        combined_shape = combined_shape.buffer(
+            self.options.offset * PIXELS_PER_MM,
+            cap_style=int(self.options.join_style),
+            join_style=int(self.options.join_style),
+            mitre_limit=int(self.options.mitre_limit)
+        )
+        combined_shape = combined_shape.simplify(0.3)
+        combined_shape = ensure_multi_polygon(combined_shape)
+
+        self.insert_knockdown_elements(combined_shape)
+
+    def insert_knockdown_elements(self, combined_shape):
+        first = self.svg.selection.rendering_order()[0]
+        try:
+            parent = first.getparent()
+            index = parent.index(first)
+        except AttributeError:
+            parent = self.svg
+            index = 0
+        transform = get_correction_transform(first)
+
+        for polygon in combined_shape.geoms:
+            d = str(Path(polygon.exterior.coords))
+            if self.options.keep_holes:
+                for interior in polygon.interiors:
+                    d += str(Path(interior.coords))
+
+            path = PathElement()
+            path.set('d', d)
+            path.label = self.svg.get_unique_id('Knockdown ')
+            path.set('transform', transform)
+
+            path.set('inkstitch:row_spacing_mm', '2.6')
+            path.set('inkstitch:fill_underlay_angle', '60 -60')
+            path.set('inkstitch:fill_underlay_max_stitch_length_mm', '3')
+            path.set('inkstitch:fill_underlay_row_spacing_mm', '2.6')
+            path.set('inkstitch:underlay_underpath', 'False')
+            path.set('inkstitch:underpath', 'False')
+            path.set('inkstitch:staggers', '2')
+            path.set('style', 'fill:black;')
+
+            parent.insert(index, path)