1 files changed, 120 insertions, 0 deletions
diff --git a/io_import_dxf/dxfgrabber/layers.py b/io_import_dxf/dxfgrabber/layers.py
new file mode 100755
index 00000000..de6ae39f
--- /dev/null
+++ b/io_import_dxf/dxfgrabber/layers.py
@@ -0,0 +1,120 @@
+# Purpose: handle layers
+# Created: 21.07.12
+# Copyright (C) 2012, Manfred Moitzi
+# License: MIT License
+
+__author__ = "mozman <mozman@gmx.at>"
+
+from .tags import TagGroups
+from .tags import ClassifiedTags
+from .dxfentity import DXFEntity
+
+from .dxfattr import DXFAttr, DXFAttributes, DefSubclass
+
+
+class Layer(object):
+    def __init__(self, wrapper):
+        self.name = wrapper.get_dxf_attrib('name')
+        self.color = wrapper.get_color()
+        self.linetype = wrapper.get_dxf_attrib('linetype')
+        self.locked = wrapper.is_locked()
+        self.frozen = wrapper.is_frozen()
+        self.on = wrapper.is_on()
+
+
+class Table(object):
+
+    def __init__(self):
+        self._table_entries = dict()
+
+    # start public interface
+
+    def get(self, name, default=KeyError):
+        try:
+            return self._table_entries[name]
+        except KeyError:
+            if default is KeyError:
+                raise
+            else:
+                return default
+
+    def __getitem__(self, item):
+        return self.get(item)
+
+    def __contains__(self, name):
+        return name in self._table_entries
+
+    def __iter__(self):
+        return iter(self._table_entries.values())
+
+    def __len__(self):
+        return len(self._table_entries)
+
+    def names(self):
+        return sorted(self._table_entries.keys())
+
+    # end public interface
+
+    def _classified_tags(self, tags):
+        groups = TagGroups(tags)
+        assert groups.get_name(0) == 'TABLE'
+        assert groups.get_name(-1) == 'ENDTAB'
+        for entrytags in groups[1:-1]:
+            yield ClassifiedTags(entrytags)
+
+
+class LayerTable(Table):
+    name = 'layers'
+
+    @staticmethod
+    def from_tags(tags, drawing):
+        dxfversion = drawing.dxfversion
+        layers = LayerTable()
+        for entrytags in layers._classified_tags(tags):
+            dxflayer = layers.wrap(entrytags, dxfversion)
+            layers._table_entries[dxflayer.get_dxf_attrib('name')] = Layer(dxflayer)
+        return layers
+
+    @staticmethod
+    def wrap(tags, dxfversion):
+        return DXF12Layer(tags) if dxfversion == "AC1009" else DXF13Layer(tags)
+
+
+class DXF12Layer(DXFEntity):
+    DXFATTRIBS = DXFAttributes(DefSubclass(None, {
+        'handle': DXFAttr(5),
+        'name': DXFAttr(2),
+        'flags': DXFAttr(70),
+        'color': DXFAttr(62),  # dxf color index, if < 0 layer is off
+        'linetype': DXFAttr(6),
+        }))
+    LOCK = 0b00000100
+    FROZEN = 0b00000001
+
+    def is_frozen(self):
+        return self.get_dxf_attrib('flags') & DXF12Layer.FROZEN > 0
+
+    def is_locked(self):
+        return self.get_dxf_attrib('flags') & DXF12Layer.LOCK > 0
+
+    def is_off(self):
+        return self.get_dxf_attrib('color') < 0
+
+    def is_on(self):
+        return not self.is_off()
+
+    def get_color(self):
+        return abs(self.get_dxf_attrib('color'))
+
+none_subclass = DefSubclass(None, {'handle': DXFAttr(5)})
+symbol_subclass = DefSubclass('AcDbSymbolTableRecord', {})
+layer_subclass = DefSubclass('AcDbLayerTableRecord', {
+    'name': DXFAttr(2),  # layer name
+    'flags': DXFAttr(70),
+    'color': DXFAttr(62),  # dxf color index
+    'linetype': DXFAttr(6),  # linetype name
+})
+
+
+class DXF13Layer(DXF12Layer):
+    DXFATTRIBS = DXFAttributes(none_subclass, symbol_subclass, layer_subclass)