dxf export: Use different colors for layers.

With this change, different colors are assigned to shapes. Shapes on the same layer get the same color. This allows them to be grouped by color by software that doesn’t support layers (e.g. Lasercut 5.3).

1 files changed, 18 insertions, 8 deletions

diff --git a/support/dxf_export/effect.py b/support/dxf_export/effect.py
index 52915cc..8168d3f 100644
--- a/support/dxf_export/effect.py
+++ b/support/dxf_export/effect.py
@@ -32,6 +32,7 @@ class DXFExportEffect(inkex.Effect):
 		
 		self._dxf_instructions = []
 		self._handle = 255
+		self._layer_indices = { }
 		self._flatness = float(os.environ['DXF_FLATNESS'])
 	
 	def _get_user_unit(self):
@@ -66,13 +67,22 @@ class DXFExportEffect(inkex.Effect):
 	def _get_document_height_attr(self):
 		return self.document.getroot().xpath('@height', namespaces = inkex.NSS)[0]
 	
+	def _get_layer_index(self, layer_name):
+		index = self._layer_indices.get(layer_name)
+		
+		if index is None:
+			index = len(self._layer_indices)
+			self._layer_indices[layer_name] = index
+		
+		return index
+	
 	def _add_instruction(self, code, value):
 		self._dxf_instructions.append((code, str(value)))
 	
-	def _add_dxf_line(self, layer, csp):
+	def _add_dxf_line(self, layer_name, csp):
 		self._add_instruction(0, 'LINE')
-		self._add_instruction(8, layer)
-		self._add_instruction(62, 4)
+		self._add_instruction(8, layer_name)
+		self._add_instruction(62, self._get_layer_index(layer_name))
 		self._add_instruction(5, '{:x}'.format(self._handle))
 		self._add_instruction(100, 'AcDbEntity')
 		self._add_instruction(100, 'AcDbLine')
@@ -83,7 +93,7 @@ class DXFExportEffect(inkex.Effect):
 		self._add_instruction(21, repr(csp[1][1]))
 		self._add_instruction(31, 0.0)
 	
-	def _add_dxf_path(self, layer, path):
+	def _add_dxf_path(self, layer_name, path):
 		cspsubdiv.cspsubdiv(path, self._flatness)
 		
 		for sub in path:
@@ -91,10 +101,10 @@ class DXFExportEffect(inkex.Effect):
 				self._handle += 1
 				s = sub[i]
 				e = sub[i + 1]
-				self._add_dxf_line(layer, [s[1], e[1]])
+				self._add_dxf_line(layer_name, [s[1], e[1]])
 	
 	def _add_dxf_shape(self, node, document_transform, element_transform):
-		layer = self._get_inkscape_layer(node)
+		layer_name = self._get_inkscape_layer_name(node)
 		path = cubicsuperpath.parsePath(node.get('d'))
 		
 		transform = simpletransform.composeTransform(
@@ -103,7 +113,7 @@ class DXFExportEffect(inkex.Effect):
 		
 		simpletransform.applyTransformToPath(transform, path)
 		
-		self._add_dxf_path(layer, path)
+		self._add_dxf_path(layer_name, path)
 	
 	def effect(self):
 		user_unit = self._get_user_unit()
@@ -153,7 +163,7 @@ class DXFExportEffect(inkex.Effect):
 		return value * cls._get_unit_factor(unit, default_unit_factor)
 	
 	@classmethod
-	def _get_inkscape_layer(cls, node):
+	def _get_inkscape_layer_name(cls, node):
 		while node is not None:
 			layer = node.get(inkex.addNS('label', 'inkscape'))