add double (fermat) spiral

3 files changed, 64 insertions, 18 deletions

diff --git a/lib/elements/fill_stitch.py b/lib/elements/fill_stitch.py
index 2f8687a1..70d4f356 100644
--- a/lib/elements/fill_stitch.py
+++ b/lib/elements/fill_stitch.py
@@ -103,7 +103,7 @@ class FillStitch(EmbroideryElement):
 
     @property
     @param('tangential_strategy', _('Tangential strategy'), type='dropdown', default=1,
-           options=[_("Inner to Outer"), _("Single spiral")], select_items=[('fill_method', 1)], sort_index=2)
+           options=[_("Inner to Outer"), _("Single spiral"), _("Double spiral")], select_items=[('fill_method', 1)], sort_index=2)
     def tangential_strategy(self):
         return self.get_int_param('tangential_strategy', 1)
 
diff --git a/lib/stitches/tangential_fill_stitch_line_creator.py b/lib/stitches/tangential_fill_stitch_line_creator.py
index 78213384..69bb13f2 100644
--- a/lib/stitches/tangential_fill_stitch_line_creator.py
+++ b/lib/stitches/tangential_fill_stitch_line_creator.py
@@ -84,7 +84,8 @@ def make_tree_uniform(tree, clockwise=True):
 # Used to define which stitching strategy shall be used
 class StitchingStrategy(IntEnum):
     INNER_TO_OUTER = 0
-    SPIRAL = 1
+    SINGLE_SPIRAL = 1
+    DOUBLE_SPIRAL = 2
 
 
 def check_and_prepare_tree_for_valid_spiral(tree):
@@ -158,7 +159,7 @@ def offset_poly(poly, offset, join_style, stitch_distance, min_stitch_distance,
      at this position
     """
 
-    if strategy == StitchingStrategy.SPIRAL and len(poly.interiors) > 1:
+    if strategy in (StitchingStrategy.SINGLE_SPIRAL, StitchingStrategy.DOUBLE_SPIRAL) and len(poly.interiors) > 1:
         raise ValueError(
             "Single spiral geometry must not have more than one hole!")
 
@@ -293,10 +294,15 @@ def offset_poly(poly, offset, join_style, stitch_distance, min_stitch_distance,
             tree, 'root', abs(offset), stitch_distance, min_stitch_distance, starting_point, offset_by_half, avoid_self_crossing)
         path = [Stitch(*point) for point in connected_line.coords]
         return running_stitch(path, stitch_distance), "whatever"
-    elif strategy == StitchingStrategy.SPIRAL:
+    elif strategy == StitchingStrategy.SINGLE_SPIRAL:
         if not check_and_prepare_tree_for_valid_spiral(tree):
             raise ValueError("Geometry cannot be filled with one spiral!")
-        (connected_line, connected_line_origin) = tangential_fill_stitch_pattern_creator.connect_raster_tree_spiral(
+        (connected_line, connected_line_origin) = tangential_fill_stitch_pattern_creator.connect_raster_tree_single_spiral(
+            tree, offset, stitch_distance, min_stitch_distance, starting_point, offset_by_half)
+    elif strategy == StitchingStrategy.DOUBLE_SPIRAL:
+        if not check_and_prepare_tree_for_valid_spiral(tree):
+            raise ValueError("Geometry cannot be filled with a double spiral!")
+        (connected_line, connected_line_origin) = tangential_fill_stitch_pattern_creator.connect_raster_tree_double_spiral(
             tree, offset, stitch_distance, min_stitch_distance, starting_point, offset_by_half)
     else:
         raise ValueError("Invalid stitching stratety!")
diff --git a/lib/stitches/tangential_fill_stitch_pattern_creator.py b/lib/stitches/tangential_fill_stitch_pattern_creator.py
index 2556d58c..edc6e0af 100644
--- a/lib/stitches/tangential_fill_stitch_pattern_creator.py
+++ b/lib/stitches/tangential_fill_stitch_pattern_creator.py
@@ -1,5 +1,5 @@
-import math
 from collections import namedtuple
+from itertools import chain
 import networkx as nx
 import numpy as np
 import trimesh
@@ -259,7 +259,7 @@ def interpolate_linear_rings(ring1, ring2, max_stitch_length, start=None):
     return result.simplify(constants.simplification_threshold, False)
 
 
-def connect_raster_tree_spiral(tree, used_offset, stitch_distance, min_stitch_distance, close_point, offset_by_half):  # noqa: C901
+def connect_raster_tree_single_spiral(tree, used_offset, stitch_distance, min_stitch_distance, close_point, offset_by_half):  # noqa: C901
     """
     Takes the offsetted curves organized as tree, connects and samples them as a spiral.
     It expects that each node in the tree has max. one child
@@ -281,21 +281,61 @@ def connect_raster_tree_spiral(tree, used_offset, stitch_distance, min_stitch_di
      placed at this position
     """
 
-    if not tree['root']:  # if node has no children
-        stitches = [Stitch(*point) for point in tree.nodes['root'].val.coords]
-        return running_stitch(stitches, stitch_distance)
+    starting_point = close_point.coords[0]
+
+    rings = [tree.nodes[node].val for node in nx.dfs_preorder_nodes(tree, 'root')]
+
+    path = make_spiral(rings, stitch_distance, starting_point)
+    path = [Stitch(*stitch) for stitch in path]
+
+    return running_stitch(path, stitch_distance), None
+
+
+def connect_raster_tree_double_spiral(tree, used_offset, stitch_distance, min_stitch_distance, close_point, offset_by_half):  # noqa: C901
+    """
+    Takes the offsetted curves organized as tree, connects and samples them as a spiral.
+    It expects that each node in the tree has max. one child
+    Input:
+    -tree: contains the offsetted curves in a hierarchical organized
+     data structure.
+    -used_offset: used offset when the offsetted curves were generated
+    -stitch_distance: maximum allowed distance between two points
+     after sampling
+    -min_stitch_distance stitches within a row shall be at least min_stitch_distance apart. Stitches connecting
+     offsetted paths might be shorter.
+    -close_point: defines the beginning point for stitching
+     (stitching starts always from the undisplaced curve)
+    -offset_by_half: If true the resulting points are interlaced otherwise not.
+    Return values:
+    -All offsetted curves connected to one spiral and sampled with
+     points obeying stitch_distance and offset_by_half
+    -Tag (origin) of each point to analyze why a point was
+     placed at this position
+    """
 
     starting_point = close_point.coords[0]
-    path = []
-    for node in nx.dfs_preorder_nodes(tree, 'root'):
-        if tree[node]:
-            ring1 = tree.nodes[node].val
-            child = list(tree.successors(node))[0]
-            ring2 = tree.nodes[child].val
 
-            spiral_part = interpolate_linear_rings(ring1, ring2, stitch_distance, starting_point)
-            path.extend(spiral_part.coords)
+    rings = [tree.nodes[node].val for node in nx.dfs_preorder_nodes(tree, 'root')]
 
+    path = make_fermat_spiral(rings, stitch_distance, starting_point)
     path = [Stitch(*stitch) for stitch in path]
 
     return running_stitch(path, stitch_distance), None
+
+
+def make_fermat_spiral(rings, stitch_distance, starting_point):
+    forward = make_spiral(rings[::2], stitch_distance, starting_point)
+    back = make_spiral(rings[1::2], stitch_distance, starting_point)
+    back.reverse()
+
+    return chain(forward, back)
+
+
+def make_spiral(rings, stitch_distance, starting_point):
+    path = []
+
+    for ring1, ring2 in zip(rings[:-1], rings[1:]):
+        spiral_part = interpolate_linear_rings(ring1, ring2, stitch_distance, starting_point)
+        path.extend(spiral_part.coords)
+
+    return path