fix schemaLocation syntax for ALTO ns

README.md

@@ -1,6 +1,6 @@
 # ocrd-page-to-alto
 
-> Convert PAGE (2019) to ALTO (4)
+> Convert PAGE (v. 2019) to ALTO (v. 2.0 - 4.2)
 
 [![image](https://circleci.com/gh/kba/page-to-alto.svg?style=svg)](https://circleci.com/gh/kba/page-to-alto)
 
@@ -31,3 +31,4 @@
 * [X] ~~xHeight~~ no equivalent in ALTO :(
 * [X] ~~letterSpaced~~ no equivalent in ALTO :(
 * [x] ProcessingStep
+* [x] differentiate/select ALTO versions

ocrd_page_to_alto/cli.py

@@ -7,6 +7,8 @@
 
 @click.command(context_settings=CONTEXT_SETTINGS)
 @ocrd_loglevel
+@click.option('--alto-version', default='4.2', help='Choose version of ALTO-XML schema to produce (older versions may not preserve all features)',
+              type=click.Choice(['4.2', '4.1', '4.0', '3.1', '3.0', '2.1', '2.0']))
 @click.option('--check-words/--no-check-words', default=True, help='Check whether PAGE-XML contains any Words and fail if not')
 @click.option('--check-border/--no-check-border', default=True, help='Check whether PAGE-XML contains Border or PrintSpace')
 @click.option('--skip-empty-lines/--no-skip-empty-lines', default=False, help='Whether to omit or keep empty lines in PAGE-XML')
@@ -18,12 +20,13 @@
 @click.option('-O', '--output-file', default='-', help='Output filename (or "-" for standard output, the default)',
               type=click.Path(dir_okay=False, writable=True, exists=False, allow_dash=True))
 @click.argument('filename',  type=click.Path(dir_okay=False, exists=True))
-def main(log_level, check_words, check_border, skip_empty_lines, trailing_dash_to_hyp, dummy_textline, dummy_word, textequiv_index, textequiv_fallback_strategy, output_file, filename):
+def main(log_level, alto_version, check_words, check_border, skip_empty_lines, trailing_dash_to_hyp, dummy_textline, dummy_word, textequiv_index, textequiv_fallback_strategy, output_file, filename):
     """
     Convert PAGE to ALTO
     """
     initLogging()
     converter = OcrdPageAltoConverter(
+        alto_version=alto_version,
         page_filename=filename,
         check_words=check_words,
         check_border=check_border,

ocrd_page_to_alto/convert.py

@@ -1,5 +1,6 @@
 # pylint: disable=no-member, c-extension-no-member
 from json import dumps
+from packaging import version
 
 from lxml import etree as ET
 from ocrd_models.ocrd_page import (
@@ -22,7 +23,7 @@
 
 NAMESPACES = {**NAMESPACES_}
 NAMESPACES['xsi'] = 'http://www.w3.org/2001/XMLSchema-instance'
-NAMESPACES['alto'] = 'http://www.loc.gov/standards/alto/ns-v4#'
+NAMESPACES['alto'] = 'http://www.loc.gov/standards/alto/ns-v%s#'
 
 REGION_PAGE_TO_ALTO = {
     'Text': 'TextBlock',
@@ -33,7 +34,6 @@
     'Image': 'Illustration',
     "Table": 'ComposedBlock',
     # TODO how to handle these
-    "Chart": None,
     "Maths": None,
     "Chem": None,
     "Music": None,
@@ -45,11 +45,22 @@
 
 HYPHEN_CHARS = ['-', '⸗', '=']
 
+XSD_ALTO_URLS = {
+    '4.2': 'http://www.loc.gov/standards/alto/v4/alto-4-2.xsd',
+    '4.1': 'http://www.loc.gov/standards/alto/v4/alto-4-1.xsd',
+    '4.0': 'http://www.loc.gov/standards/alto/v4/alto-4-0.xsd',
+    '3.1': 'http://www.loc.gov/standards/alto/v3/alto-3-1.xsd',
+    '3.0': 'http://www.loc.gov/standards/alto/v3/alto-3-0.xsd',
+    '2.1': 'http://www.loc.gov/standards/alto/alto.xsd',
+    '2.0': 'http://www.loc.gov/standards/alto/v2/alto-2-0.xsd'
+}
+
 class OcrdPageAltoConverter():
 
     def __init__(
         self,
         *,
+        alto_version='4.2',
         check_words=True,
         check_border=True,
         skip_empty_lines=False,
@@ -65,6 +76,7 @@ def __init__(
     ):
         """
         Keyword Args:
+            alto_version (string): Version of ALTO-XML schema to produce (older versions may not preserve all features)
             check_words (boolean): Whether to check if PAGE-XML contains any words before conversion and fail if not
             check_border (boolean): Whether to abort if neither Border nor PrintSpace is defined
             skip_empty_lines (boolean): Whether to omit empty lines completely (True) or create a placeholder empty String in ALTO (False)
@@ -76,6 +88,9 @@ def __init__(
         """
         if not (page_filename or page_etree or pcgts):
             raise ValueError("Must pass either pcgts, page_etree or page_filename to constructor")
+        if alto_version not in XSD_ALTO_URLS:
+            raise ValueError("Converting to ALTO-XML v%s is not supported" % alto_version)
+        self.alto_version = alto_version
         self.skip_empty_lines = skip_empty_lines
         self.trailing_dash_to_hyp = trailing_dash_to_hyp
         self.dummy_textline = dummy_textline
@@ -97,12 +112,16 @@ def __init__(
         self.textequiv_fallback_strategy = textequiv_fallback_strategy
         self.alto_alto, self.alto_description, self.alto_styles, self.alto_tags, self.alto_page = self.create_alto()
         self.alto_printspace = self.convert_border()
-        self.textstyle_mgr = TextStylesManager()
-        self.parastyle_mgr = ParagraphStyleManager()
-        self.layouttag_mgr = LayoutTagManager()
+        self.textstyle_mgr = TextStylesManager(self.alto_version)
+        self.parastyle_mgr = ParagraphStyleManager(self.alto_version)
+        self.layouttag_mgr = LayoutTagManager(self.alto_version)
 
     def __str__(self):
-        return ET.tostring(self.alto_alto, pretty_print=True).decode('utf-8')
+        return ET.tostring(self.alto_alto,
+                           pretty_print=True,
+                           xml_declaration=True,
+                           standalone=True,
+                           encoding="UTF-8").decode('utf-8')
 
     def to_etree(self):
         return self.alto_alto
@@ -120,12 +139,19 @@ def check_border(self, tree):
 
     def create_alto(self):
         alto_alto = ET.Element('alto')
-        setxml(alto_alto, 'xmlns', NAMESPACES['alto'])
-        setxml(alto_alto, '{%s}schemaLocation' % NAMESPACES['xsi'], "http://www.loc.gov/standards/alto/v4/alto-4-2.xsd")
+        setxml(alto_alto, 'xmlns', NAMESPACES['alto'] % self.alto_version[:1])
+        setxml(alto_alto, '{%s}schemaLocation' % NAMESPACES['xsi'],
+               "%s %s" % (NAMESPACES['alto'] % self.alto_version[:1],
+                          XSD_ALTO_URLS[self.alto_version]))
         alto_description = ET.SubElement(alto_alto, 'Description')
         alto_styles = ET.SubElement(alto_alto, 'Styles')
-        alto_tags = ET.SubElement(alto_alto, 'Tags')
+        if version.parse(self.alto_version) >= version.parse('2.1'):
+            alto_tags = ET.SubElement(alto_alto, 'Tags')
+        else:
+            alto_tags = None
         alto_layout = ET.SubElement(alto_alto, 'Layout')
+        if version.parse(self.alto_version) >= version.parse('3.0'):
+            setxml(alto_alto, 'SCHEMAVERSION', self.alto_version)
         alto_page = ET.SubElement(alto_layout, 'Page')
         setxml(alto_page, 'ID', getattr(self.page_pcgts, 'pcGtsId', 'page0'))
         setxml(alto_page, 'PHYSICAL_IMG_NR', 0)
@@ -144,25 +170,25 @@ def convert(self):
     def convert_styles(self):
         self.textstyle_mgr.to_xml(self.alto_styles)
         self.parastyle_mgr.to_xml(self.alto_styles)
-        self.layouttag_mgr.to_xml(self.alto_tags)
+        if version.parse(self.alto_version) >= version.parse('2.1'):
+            self.layouttag_mgr.to_xml(self.alto_tags)
 
     def convert_reading_order(self):
         index_order = [x.id for x in self.page_page.get_AllRegions(order='reading-order', depth=0)]
         for id_cur, id_next in zip(index_order[:-1], index_order[1:]):
             self.alto_printspace.find('.//*[@ID="%s"]' % id_cur).set('IDNEXT', id_next)
 
     def convert_border(self):
-        page_width = self.page_page.imageHeight
+        page_width = self.page_page.imageWidth
         page_height = self.page_page.imageHeight
         setxml(self.alto_page, 'WIDTH', page_width)
         setxml(self.alto_page, 'HEIGHT',  page_height)
-        self.alto_page.set('WIDTH', str(page_width))
-        page_border = self.page_page.get_Border()
+        page_printspace = self.page_page.get_PrintSpace()
         dummy_printspace = False
-        if page_border is None:
-            self.logger.warning("PAGE-XML has no Border, trying to fall back to PrintSpace")
-            page_border = self.page_page.get_PrintSpace()
-            if page_border is None:
+        if page_printspace is None:
+            self.logger.warning("PAGE-XML has no PrintSpace, trying to fall back to Border")
+            page_printspace = self.page_page.get_Border()
+            if page_printspace is None:
                 dummy_printspace = True
 
         if dummy_printspace:
@@ -172,7 +198,7 @@ def convert_border(self):
                 for att in ('VPOS', 'HPOS', 'HEIGHT', 'WIDTH'):
                     setxml(margin, att, 0)
         else:
-            xywh = xywh_from_points(page_border.get_Coords().points)
+            xywh = xywh_from_points(page_printspace.get_Coords().points)
             alto_topmargin = ET.SubElement(self.alto_page, 'TopMargin')
             setxml(alto_topmargin, 'VPOS', 0)
             setxml(alto_topmargin, 'HPOS', 0)
@@ -193,11 +219,21 @@ def convert_border(self):
             setxml(alto_bottommargin, 'HPOS', 0)
             setxml(alto_bottommargin, 'HEIGHT', page_height - (xywh['y'] + xywh['h']))
             setxml(alto_bottommargin, 'WIDTH', page_width)
+            set_alto_xywh_from_coords(alto_printspace, page_printspace)
+            if version.parse(self.alto_version) >= version.parse('3.1'):
+                set_alto_shape_from_coords(alto_printspace, page_printspace)
 
         alto_printspace = ET.SubElement(self.alto_page, 'PrintSpace')
-        if page_border:
-            set_alto_xywh_from_coords(alto_printspace, page_border)
-            set_alto_shape_from_coords(alto_printspace, page_border)
+        if dummy_printspace:
+            setxml(alto_printspace, 'VPOS', 0)
+            setxml(alto_printspace, 'HPOS', 0)
+            setxml(alto_printspace, 'HEIGHT', page_height)
+            setxml(alto_printspace, 'WIDTH', page_width)
+        else:
+            set_alto_xywh_from_coords(alto_printspace, page_printspace)
+            if version.parse(self.alto_version) >= version.parse('3.1'):
+                set_alto_shape_from_coords(alto_printspace, page_printspace)
+
         return alto_printspace
 
     def convert_metadata(self):
@@ -210,7 +246,11 @@ def convert_metadata(self):
         if not page_metadata:
             return
         for step_idx, step_page in enumerate([x for x in page_metadata.get_MetadataItem() if x.get_type() == 'processingStep']):
-            step_alto = ET.SubElement(self.alto_description, 'Processing')
+            if version.parse(self.alto_version) >= version.parse('4.0'):
+                step_alto = ET.SubElement(self.alto_description, 'Processing')
+            else:
+                step_alto = ET.SubElement(self.alto_description, 'OCRProcessing')
+                step_alto = ET.SubElement(step_alto, 'ocrProcessingStep')
             setxml(step_alto, 'ID', f'{step_page.value}-{step_idx}')
             step_alto_description = ET.SubElement(step_alto, 'processingStepDescription')
             step_alto_description.text = step_page.name
@@ -236,8 +276,10 @@ def _convert_textlines(self, reg_alto, reg_page):
             line_alto = ET.SubElement(reg_alto, 'TextLine')
             set_alto_id_from_page_id(line_alto, line_page)
             set_alto_xywh_from_coords(line_alto, line_page)
-            set_alto_shape_from_coords(line_alto, line_page)
-            set_alto_lang_from_page_lang(line_alto, line_page)
+            if version.parse(self.alto_version) >= version.parse('3.1'):
+                set_alto_shape_from_coords(line_alto, line_page)
+            if version.parse(self.alto_version) >= version.parse('2.1'):
+                set_alto_lang_from_page_lang(line_alto, line_page)
             self.textstyle_mgr.set_alto_styleref_from_textstyle(line_alto, line_page)
             if is_empty_line:
                 word_alto_empty = ET.SubElement(line_alto, 'String')
@@ -251,8 +293,10 @@ def _convert_textlines(self, reg_alto, reg_page):
                 word_alto = ET.SubElement(line_alto, 'String')
                 set_alto_id_from_page_id(word_alto, word_page)
                 set_alto_xywh_from_coords(word_alto, word_page)
-                set_alto_shape_from_coords(word_alto, word_page)
-                set_alto_lang_from_page_lang(word_alto, word_page)
+                if version.parse(self.alto_version) >= version.parse('3.1'):
+                    set_alto_shape_from_coords(word_alto, word_page)
+                if version.parse(self.alto_version) >= version.parse('2.1'):
+                    set_alto_lang_from_page_lang(word_alto, word_page)
                 self.textstyle_mgr.set_alto_styleref_from_textstyle(word_alto, word_page)
                 word_content = get_nth_textequiv(word_page, self.textequiv_index, self.textequiv_fallback_strategy)
                 if not is_last_word:
@@ -273,13 +317,17 @@ def _convert_table(self, parent_alto, parent_page, level=0):
             if parent_page.get_TextRegion():
                 reg_alto = ET.SubElement(parent_alto, 'ComposedBlock')
                 set_alto_id_from_page_id(reg_alto, parent_page) # TODO not unique!
-                set_alto_lang_from_page_lang(reg_alto, parent_page)
+                if version.parse(self.alto_version) >= version.parse('2.1'):
+                    set_alto_lang_from_page_lang(reg_alto, parent_page)
                 for reg_page in parent_page.get_TextRegion():
                     self._convert_table(reg_alto, reg_page, level=level + 1)
             else:
                 textblock_alto = ET.SubElement(parent_alto, 'TextBlock')
                 set_alto_id_from_page_id(textblock_alto, parent_page)
-                set_alto_lang_from_page_lang(textblock_alto, parent_page)
+                if version.parse(self.alto_version) >= version.parse('2.1'):
+                    set_alto_lang_from_page_lang(textblock_alto, parent_page)
+                else:
+                    set_alto_lang_from_page_lang(textblock_alto, parent_page, attribute_name="language")
                 self._convert_textlines(textblock_alto, parent_page)
 
     def convert_text(self):
@@ -291,11 +339,14 @@ def convert_text(self):
             reg_alto = ET.SubElement(self.alto_printspace, reg_alto_type)
             set_alto_id_from_page_id(reg_alto, reg_page)
             set_alto_xywh_from_coords(reg_alto, reg_page)
-            set_alto_shape_from_coords(reg_alto, reg_page)
-            set_alto_lang_from_page_lang(reg_alto, reg_page)
+            if version.parse(self.alto_version) >= version.parse('3.1'):
+                set_alto_shape_from_coords(reg_alto, reg_page)
+            if version.parse(self.alto_version) >= version.parse('2.1'):
+                set_alto_lang_from_page_lang(reg_alto, reg_page)
             self.textstyle_mgr.set_alto_styleref_from_textstyle(reg_alto, reg_page)
             self.parastyle_mgr.set_alto_styleref_from_textstyle(reg_alto, reg_page)
-            self.layouttag_mgr.set_alto_tag_from_type(reg_alto, reg_page)
+            if version.parse(self.alto_version) >= version.parse('2.1'):
+                self.layouttag_mgr.set_alto_tag_from_type(reg_alto, reg_page)
             if reg_page_type == 'Text':
                 self._convert_textlines(reg_alto, reg_page)
             elif reg_page_type == 'Table':

ocrd_page_to_alto/styles.py

@@ -1,12 +1,14 @@
 from lxml import etree as ET
+from packaging import version
 
 class TextStylesManager():
     """
     Keeps track of combination of PAGE attributes on the element level to map them
     to ALTO TextStyles. The @ID is a concatenation of the values with a prefix.
     """
 
-    def __init__(self):
+    def __init__(self, alto_version):
+        self.alto_version = alto_version
         self._elements = set()
         self.prefix = 'textstyle-'
         self.fields = ['font_family', 'font_type', 'font_width', 'font_size', 'font_color', 'font_style']
@@ -66,7 +68,8 @@ def from_textstyle(self, textstyle):
             font_style.append('italics')
         if textstyle.underlined:
             font_style.append('underline')
-        for att in ('bold', 'smallCaps', 'strikethrough', 'subscript', 'superscript'):
+        for att in ('bold', 'smallCaps', 'strikethrough' if version.parse(self.alto_version) >= version.parse('4.2') else '',
+                    'subscript', 'superscript'):
             if getattr(textstyle, att):
                 font_style.append(att.lower())
         if font_style:
@@ -97,8 +100,8 @@ def to_xml(self, alto_parent):
 
 class ParagraphStyleManager(TextStylesManager):
 
-    def __init__(self):
-        super().__init__()
+    def __init__(self, alto_version):
+        super().__init__(alto_version)
         self.fields = ['align', 'left', 'right', 'line_space', 'first_line']
         self.prefix = 'parastyle-'
         self.output_element = 'ParagraphStyle'
@@ -113,8 +116,8 @@ def set_alto_styleref_from_textstyle(self, reg_alto, reg_page):
 
 class LayoutTagManager(TextStylesManager):
 
-    def __init__(self):
-        super().__init__()
+    def __init__(self, alto_version):
+        super().__init__(alto_version)
         self.fields = ['label']
         self.prefix = 'layouttag-'
         self.output_element = 'LayoutTag'

ocrd_page_to_alto/utils.py

@@ -22,12 +22,12 @@ def set_alto_shape_from_coords(reg_alto, reg_page):
 def set_alto_id_from_page_id(reg_alto, reg_page):
     setxml(reg_alto, 'ID', reg_page.id)
 
-def set_alto_lang_from_page_lang(reg_alto, reg_page):
+def set_alto_lang_from_page_lang(reg_alto, reg_page, attribute_name='LANG'):
     for prefix in ('primaryL', 'secondaryL', 'l'):
         lang_page = getattr(reg_page, f'{prefix}anguage', None)
         if lang_page:
             lang_alto = langcodes.find(lang_page).to_alpha3()
-            setxml(reg_alto, 'LANG',lang_alto)
+            setxml(reg_alto, attribute_name, lang_alto)
             return
 
 def get_nth_textequiv(reg_page, textequiv_index, textequiv_fallback_strategy):