* Add support for stereoscopic 3D (disparity) (#30)

* Add style property internal consistency unit test

src/main/python/ttconv/imsc/style_properties.py

@@ -84,6 +84,19 @@ def extract(cls, context: StyleParsingContext, xml_attrib: str):
       return styles.DirectionType[xml_attrib]
 
 
+  class Disparity(StyleProperty):
+    '''Corresponds to tts:disparity.
+    '''
+
+    ns = "http://www.w3.org/ns/ttml#styling"
+    local_name = "disparity"
+    model_prop = styles.StyleProperties.Disparity
+
+    @classmethod
+    def extract(cls, context: StyleParsingContext, xml_attrib: str):
+      return StyleProperties.ttml_length_to_model(context, xml_attrib)
+
+
   class Display(StyleProperty):
     '''Corresponds to tts:display.'''
 
@@ -95,6 +108,7 @@ class Display(StyleProperty):
     def extract(cls, context: StyleParsingContext, xml_attrib: str):
       return styles.DisplayType[xml_attrib]
 
+
   class DisplayAlign(StyleProperty):
     '''Corresponds to tts:displayAlign.'''
 

src/main/python/ttconv/model.py

@@ -682,6 +682,7 @@ class Region(ContentElement):
 
   _applicableStyles = frozenset([
     StyleProperties.BackgroundColor,
+    StyleProperties.Disparity,
     StyleProperties.Display,
     StyleProperties.DisplayAlign,
     StyleProperties.Extent,

src/main/python/ttconv/style_properties.py

@@ -391,6 +391,19 @@ def make_initial_value():
     def validate(value):
       return isinstance(value, DirectionType) 
 
+  class Disparity(StyleProperty):
+    '''Corresponds to tts:disparity.'''
+
+    is_inherited = False
+    is_animatable = True
+
+    @staticmethod
+    def make_initial_value():
+      return LengthType()
+
+    @staticmethod
+    def validate(value):
+      return isinstance(value, LengthType) 
 
   class Display(StyleProperty):
     '''Corresponds to tts:display.'''
@@ -581,7 +594,10 @@ class Origin(StyleProperty):
 
     @staticmethod
     def make_initial_value():
-      return PositionType()
+      return PositionType(
+        LengthType(0, LengthType.Units.pct),
+        LengthType(0, LengthType.Units.pct)
+      )
 
     @staticmethod
     def validate(value: PositionType):
@@ -611,6 +627,10 @@ class Padding(StyleProperty):
     is_inherited = False
     is_animatable = True
 
+    @staticmethod
+    def make_initial_value():
+      return PaddingType()
+
     @staticmethod
     def validate(value):
       return isinstance(value, PaddingType)

src/test/python/test_imsc_color_parser.py

@@ -23,7 +23,7 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-'''Unit tests for the IMSC color parser'''
+'''Unit tests for the IMSC \\<color\\> parser'''
 
 # pylint: disable=R0201,C0115,C0116
 

src/test/python/test_imsc_font_families_parser.py

@@ -23,7 +23,7 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-'''Unit tests for the IMSC color parser'''
+'''Unit tests for the IMSC \\<fontFamily\\> parser'''
 
 # pylint: disable=R0201,C0115,C0116
 

src/test/python/test_model_style_properties.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+# -*- coding: UTF-8 -*-
+
+# Copyright (c) 2020, Sandflow Consulting LLC
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this
+#    list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+#    this list of conditions and the following disclaimer in the documentation
+#    and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+'''Unit tests for the style properties defined in the canonical model'''
+
+# pylint: disable=R0201,C0115,C0116
+
+import unittest
+from ttconv.style_properties import StyleProperties
+
+class TestModelStyleProperties(unittest.TestCase):
+
+  def test_make_initial(self):
+    for style in StyleProperties.ALL:
+      with self.subTest(style.__name__):
+        style.validate(style.make_initial_value())
+
+if __name__ == '__main__':
+  unittest.main()