convert to satin extension

7 files changed, 178 insertions, 22 deletions

diff --git a/inx/inkstitch_convert_to_satin.inx b/inx/inkstitch_convert_to_satin.inx
new file mode 100644
index 00000000..d71b2081
--- /dev/null
+++ b/inx/inkstitch_convert_to_satin.inx
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
+    <_name>Convert Line to Satin</_name>
+    <id>org.inkstitch.convert_to_satin</id>
+    <dependency type="executable" location="extensions">inkstitch.py</dependency>
+    <dependency type="executable" location="extensions">inkex.py</dependency>
+    <param name="extension" type="string" gui-hidden="true">convert_to_satin</param>
+    <effect>
+        <object-type>all</object-type>
+        <effects-menu>
+            <submenu _name="Embroidery" />
+        </effects-menu>
+    </effect>
+    <script>
+        <command reldir="extensions" interpreter="python">inkstitch.py</command>
+    </script>
+</inkscape-extension>
diff --git a/lib/extensions/__init__.py b/lib/extensions/__init__.py
index 8b243176..30a08c9f 100644
--- a/lib/extensions/__init__.py
+++ b/lib/extensions/__init__.py
@@ -8,3 +8,4 @@ from output import Output
 from zip import Zip
 from flip import Flip
 from commands import Commands
+from convert_to_satin import ConvertToSatin
diff --git a/lib/extensions/commands.py b/lib/extensions/commands.py
index 2f3006ff..353c9874 100644
--- a/lib/extensions/commands.py
+++ b/lib/extensions/commands.py
@@ -12,7 +12,7 @@ from ..i18n import _
 from ..elements import SatinColumn
 from ..utils import get_bundled_dir, cache
 from ..svg.tags import SVG_DEFS_TAG, SVG_GROUP_TAG, SVG_USE_TAG, SVG_PATH_TAG, INKSCAPE_GROUPMODE, XLINK_HREF, CONNECTION_START, CONNECTION_END, CONNECTOR_TYPE
-from ..svg import get_node_transform
+from ..svg import get_correction_transform
 
 
 class Commands(InkstitchExtension):
@@ -48,21 +48,6 @@ class Commands(InkstitchExtension):
         if self.defs.find(path) is None:
             self.defs.append(deepcopy(self.symbol_defs.find(path)))
 
-    def get_correction_transform(self, node):
-        # if we want to place our new nodes in the same group as this node,
-        # then we'll need to factor in the effects of any transforms set on
-        # the parents of this node.
-
-        # we can ignore the transform on the node itself since it won't apply
-        # to the objects we add
-        transform = get_node_transform(node.getparent())
-
-        # now invert it, so that we can position our objects in absolute
-        # coordinates
-        transform = simpletransform.invertTransform(transform)
-
-        return simpletransform.formatTransform(transform)
-
     def add_connector(self, symbol, element):
         # I'd like it if I could position the connector endpoint nicely but inkscape just
         # moves it to the element's center immediately after the extension runs.
@@ -74,7 +59,7 @@ class Commands(InkstitchExtension):
                 "id": self.uniqueId("connector"),
                 "d": "M %s,%s %s,%s" % (start_pos[0], start_pos[1], end_pos.x, end_pos.y),
                 "style": "stroke:#000000;stroke-width:1px;stroke-opacity:0.5;fill:none;",
-                "transform": self.get_correction_transform(symbol),
+                "transform": get_correction_transform(symbol),
                 CONNECTION_START: "#%s" % symbol.get('id'),
                 CONNECTION_END: "#%s" % element.node.get('id'),
                 CONNECTOR_TYPE: "polyline",
@@ -126,7 +111,7 @@ class Commands(InkstitchExtension):
                     "width": "100%",
                     "x": str(pos.x),
                     "y": str(pos.y),
-                    "transform": self.get_correction_transform(element.node)
+                    "transform": get_correction_transform(element.node)
                 }
             )
 
diff --git a/lib/extensions/convert_to_satin.py b/lib/extensions/convert_to_satin.py
new file mode 100644
index 00000000..715853c4
--- /dev/null
+++ b/lib/extensions/convert_to_satin.py
@@ -0,0 +1,119 @@
+import inkex
+from shapely import geometry as shgeo
+from itertools import chain
+
+from .base import InkstitchExtension
+from ..svg.tags import SVG_PATH_TAG
+from ..svg import get_correction_transform, PIXELS_PER_MM
+from ..elements import Stroke
+from ..utils import Point
+
+
+class ConvertToSatin(InkstitchExtension):
+    """Convert a line to a satin column of the same width."""
+
+    def effect(self):
+        if not self.get_elements():
+            return
+
+        if not self.selected:
+            inkex.errormsg(_("Please select at least one line to convert to a satin column."))
+            return
+
+        if not all(isinstance(item, Stroke) for item in self.elements):
+            # L10N: Convert To Satin extension, user selected one or more objects that were not lines.
+            inkex.errormsg(_("Only simple lines may be converted to satin columns."))
+            return
+
+        for element in self.elements:
+            parent = element.node.getparent()
+            index = parent.index(element.node)
+            correction_transform = get_correction_transform(element.node)
+
+            for path in element.paths:
+                try:
+                    rails, rungs = self.path_to_satin(path, element.stroke_width)
+                except ValueError:
+                    inkex.errormsg(_("Cannot convert %s to a satin column because it intersects itself.  Try breaking it up into multiple paths.") % element.node.get('id'))
+
+                parent.insert(index, self.satin_to_svg_node(rails, rungs, correction_transform))
+
+            parent.remove(element.node)
+
+    def path_to_satin(self, path, stroke_width):
+        path = shgeo.LineString(path)
+
+        left_rail = path.parallel_offset(stroke_width / 2.0, 'left')
+        right_rail = path.parallel_offset(stroke_width / 2.0, 'right')
+
+        if not isinstance(left_rail, shgeo.LineString) or \
+           not isinstance(right_rail, shgeo.LineString):
+                # If the parallel offsets come out as anything but a LineString, that means the
+                # path intersects itself, when taking its stroke width into consideration.  See
+                # the last example for parallel_offset() in the Shapely documentation:
+                #   https://shapely.readthedocs.io/en/latest/manual.html#object.parallel_offset
+                raise ValueError()
+
+        # for whatever reason, shapely returns a right-side offset's coordinates in reverse
+        left_rail = list(left_rail.coords)
+        right_rail = list(reversed(right_rail.coords))
+
+        rungs = self.generate_rungs(path, stroke_width)
+
+        return (left_rail, right_rail), rungs
+
+    def generate_rungs(self, path, stroke_width):
+        rungs = []
+
+        # approximately 1cm between rungs, and we don't want them at the very start or end
+        num_rungs = int(path.length / PIXELS_PER_MM / 10) - 1
+
+        if num_rungs < 1 or num_rungs == 2:
+            # avoid 2 rungs because it can be ambiguous (which are the rails and which are the
+            # rungs?)
+            num_rungs += 1
+
+        distance_between_rungs = path.length / (num_rungs + 1)
+
+        for i in xrange(num_rungs):
+            rung_center = path.interpolate((i + 1) * distance_between_rungs)
+            rung_center = Point(rung_center.x, rung_center.y)
+
+            # TODO: use bezierslopeatt or whatever
+            # we need to calculate the normal at this point so grab another point just a little
+            # further down the path, effectively grabbing a small segment of the path
+            segment_end = path.interpolate((i + 1) * distance_between_rungs + 0.1)
+            segment_end = Point(segment_end.x, segment_end.y)
+
+            tangent = segment_end - rung_center
+            normal = tangent.unit().rotate_left()
+            offset = normal * stroke_width * 0.75
+
+            rung_start = rung_center + offset
+            rung_end = rung_center - offset
+
+            rungs.append((rung_start.as_tuple(), rung_end.as_tuple()))
+
+        return rungs
+        import sys
+        print >> sys.stderr, rails, rungs
+
+
+
+    def satin_to_svg_node(self, rails, rungs, correction_transform):
+        d = ""
+        for path in chain(rails, rungs):
+            d += "M"
+            for x, y in path:
+                d += "%s,%s " % (x, y)
+            d += " "
+
+        return inkex.etree.Element(SVG_PATH_TAG,
+            {
+                "id": self.uniqueId("path"),
+                "style": "stroke:#000000;stroke-width:1px;fill:none",
+                "transform": correction_transform,
+                "d": d,
+                "embroider_satin_column": "true",
+            }
+        )
diff --git a/lib/svg/__init__.py b/lib/svg/__init__.py
index 8e846555..429e6b5e 100644
--- a/lib/svg/__init__.py
+++ b/lib/svg/__init__.py
@@ -1,3 +1,3 @@
 from .svg import color_block_to_point_lists, render_stitch_plan
 from .units import *
-from .path import apply_transforms, get_node_transform
+from .path import apply_transforms, get_node_transform, get_correction_transform
diff --git a/lib/svg/path.py b/lib/svg/path.py
index 2d9c0ff3..00e2c269 100644
--- a/lib/svg/path.py
+++ b/lib/svg/path.py
@@ -23,3 +23,20 @@ def get_node_transform(node):
     transform = simpletransform.composeTransform(viewbox_transform, transform)
 
     return transform
+
+def get_correction_transform(node):
+    """Get a transform to apply to new siblings of this SVG node"""
+
+    # if we want to place our new nodes in the same group/layer as this node,
+    # then we'll need to factor in the effects of any transforms set on
+    # the parents of this node.
+
+    # we can ignore the transform on the node itself since it won't apply
+    # to the objects we add
+    transform = get_node_transform(node.getparent())
+
+    # now invert it, so that we can position our objects in absolute
+    # coordinates
+    transform = simpletransform.invertTransform(transform)
+
+    return simpletransform.formatTransform(transform)
diff --git a/messages.po b/messages.po
index 19400443..eb27b8a9 100644
--- a/messages.po
+++ b/messages.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2018-07-25 21:18-0400\n"
+"POT-Creation-Date: 2018-07-30 14:57-0400\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -230,14 +230,31 @@ msgstr ""
 msgid "Tip: use Path -> Object to Path to convert non-paths."
 msgstr ""
 
-#: lib/extensions/commands.py:140
+#: lib/extensions/commands.py:125
 msgid "Please select one or more objects to which to attach commands."
 msgstr ""
 
-#: lib/extensions/commands.py:148
+#: lib/extensions/commands.py:133
 msgid "Please choose one or more commands to attach."
 msgstr ""
 
+#: lib/extensions/convert_to_satin.py:20
+msgid "Please select at least one line to convert to a satin column."
+msgstr ""
+
+#. : Convert To Satin extension, user selected one or more objects that were
+#. not lines.
+#: lib/extensions/convert_to_satin.py:25
+msgid "Only simple lines may be converted to satin columns."
+msgstr ""
+
+#: lib/extensions/convert_to_satin.py:37
+#, python-format
+msgid ""
+"Cannot convert %s to a satin column because it intersects itself.  Try "
+"breaking it up into multiple paths."
+msgstr ""
+
 #: lib/extensions/embroider.py:41
 msgid ""
 "\n"