1 files changed, 104 insertions, 0 deletions
diff --git a/lib/patterns.py b/lib/patterns.py
new file mode 100644
index 00000000..5ae763fc
--- /dev/null
+++ b/lib/patterns.py
@@ -0,0 +1,104 @@
+# Authors: see git history
+#
+# 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 geometry as shgeo
+import math
+
+from .svg.tags import EMBROIDERABLE_TAGS
+from .utils import Point
+
+
+def is_pattern(node):
+    if node.tag not in EMBROIDERABLE_TAGS:
+        return False
+    style = node.get('style') or ''
+    return "marker-start:url(#inkstitch-pattern-marker)" in style
+
+
+def apply_patterns(patches, node):
+    patterns = _get_patterns(node)
+    _apply_stroke_patterns(patterns['stroke_patterns'], patches)
+    _apply_fill_patterns(patterns['fill_patterns'], patches)
+
+
+def _apply_stroke_patterns(patterns, patches):
+    for pattern in patterns:
+        for patch in patches:
+            patch_points = []
+            for i, stitch in enumerate(patch.stitches):
+                patch_points.append(stitch)
+                if i == len(patch.stitches) - 1:
+                    continue
+                intersection_points = _get_pattern_points(stitch, patch.stitches[i+1], pattern)
+                for point in intersection_points:
+                    patch_points.append(point)
+            patch.stitches = patch_points
+
+
+def _apply_fill_patterns(patterns, patches):
+    for pattern in patterns:
+        for patch in patches:
+            patch_points = []
+            for i, stitch in enumerate(patch.stitches):
+                # keep points outside the fill patter
+                if not shgeo.Point(stitch).within(pattern):
+                    patch_points.append(stitch)
+                # keep start and end points
+                elif i - 1 < 0 or i >= len(patch.stitches) - 1:
+                    patch_points.append(stitch)
+                # keep points if they have an angle
+                # the necessary angle can be variable with certain stitch types (later on)
+                # but they don't need to use filled patterns for those
+                elif not 179 < get_angle(patch.stitches[i-1], stitch, patch.stitches[i+1]) < 181:
+                    patch_points.append(stitch)
+            patch.stitches = patch_points
+
+
+def _get_patterns(node):
+    from .elements import EmbroideryElement
+    from .elements.fill import Fill
+    from .elements.stroke import Stroke
+
+    fills = []
+    strokes = []
+    xpath = "./parent::svg:g/*[contains(@style, 'marker-start:url(#inkstitch-pattern-marker)')]"
+    patterns = node.xpath(xpath, namespaces=inkex.NSS)
+    for pattern in patterns:
+        if pattern.tag not in EMBROIDERABLE_TAGS:
+            continue
+
+        element = EmbroideryElement(pattern)
+        fill = element.get_style('fill')
+        stroke = element.get_style('stroke')
+
+        if fill is not None:
+            fill_pattern = Fill(pattern).shape
+            fills.append(fill_pattern)
+
+        if stroke is not None:
+            stroke_pattern = Stroke(pattern).paths
+            line_strings = [shgeo.LineString(path) for path in stroke_pattern]
+            strokes.append(shgeo.MultiLineString(line_strings))
+
+    return {'fill_patterns': fills, 'stroke_patterns': strokes}
+
+
+def _get_pattern_points(first, second, pattern):
+    points = []
+    intersection = shgeo.LineString([first, second]).intersection(pattern)
+    if isinstance(intersection, shgeo.Point):
+        points.append(Point(intersection.x, intersection.y))
+    if isinstance(intersection, shgeo.MultiPoint):
+        for point in intersection:
+            points.append(Point(point.x, point.y))
+    # sort points after their distance to first
+    points.sort(key=lambda point: point.distance(first))
+    return points
+
+
+def get_angle(a, b, c):
+    ang = math.degrees(math.atan2(c[1]-b[1], c[0]-b[0]) - math.atan2(a[1]-b[1], a[0]-b[0]))
+    return ang + 360 if ang < 0 else ang