Initial import

diff --git a/svgwrite_inkscape_drawing.py b/svgwrite_inkscape_drawing.py
new file mode 100755 (executable)
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+++ b/svgwrite_inkscape_drawing.py
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+#!/usr/bin/env python
+#coding:utf-8
+# Author:  ao2
+# Purpose: create Inkscape layers with svgwrite
+# Created: 26.01.2018
+# License: MIT License
+# Copyright (C) 2018  Antonio Ospite <ao2@ao2.it>
+
+import svgwrite
+from svgwrite.data.types import SVGAttribute
+
+
+class InkscapeDrawing(svgwrite.Drawing):
+    """An svgwrite.Drawing subclass which supports Inkscape layers"""
+    def __init__(self, *args, **kwargs):
+        super(InkscapeDrawing, self).__init__(*args, **kwargs)
+
+        inkscape_attributes = {
+            'xmlns:inkscape': SVGAttribute('xmlns:inkscape',
+                                           anim=False,
+                                           types=[],
+                                           const=frozenset(['http://www.inkscape.org/namespaces/inkscape'])),
+            'inkscape:groupmode': SVGAttribute('inkscape:groupmode',
+                                               anim=False,
+                                               types=[],
+                                               const=frozenset(['layer'])),
+            'inkscape:label': SVGAttribute('inkscape:label',
+                                           anim=False,
+                                           types=frozenset(['string']),
+                                           const=[])
+        }
+
+        self.validator.attributes.update(inkscape_attributes)
+
+        elements = self.validator.elements
+
+        svg_attributes = set(elements['svg'].valid_attributes)
+        svg_attributes.add('xmlns:inkscape')
+        elements['svg'].valid_attributes = frozenset(svg_attributes)
+
+        g_attributes = set(elements['g'].valid_attributes)
+        g_attributes.add('inkscape:groupmode')
+        g_attributes.add('inkscape:label')
+        elements['g'].valid_attributes = frozenset(g_attributes)
+
+        self['xmlns:inkscape'] = 'http://www.inkscape.org/namespaces/inkscape'
+
+    def layer(self, **kwargs):
+        """Create an inkscape layer.
+
+        An optional 'label' keyword argument can be passed to set a user
+        friendly name for the layer."""
+        label = kwargs.pop('label', None)
+
+        new_layer = self.g(**kwargs)
+        new_layer['inkscape:groupmode'] = 'layer'
+
+        if label:
+            new_layer['inkscape:label'] = label
+
+        return new_layer
+
+
+def main():
+    svg = InkscapeDrawing('inkscape-test.svg', profile='full', size=(640, 480))
+
+    layer = svg.layer(label="Layer one")
+    svg.add(layer)
+
+    line = svg.line((100, 100), (300, 100),
+                    stroke=svgwrite.rgb(10, 10, 16, '%'),
+                    stroke_width='10')
+    layer.add(line)
+
+    text = svg.text('Test', insert=(100, 100), font_size='100', fill='red')
+    layer.add(text)
+
+    svg.save()
+
+
+if __name__ == "__main__":
+    main()