de.digitalcollections.solrocr.formats.hocr.HocrFormat Maven / Gradle / Ivy
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Solr plugin to add support for highlighting directly from various OCR formats (hOCR/ALTO/MiniOCR)
without having to store the OCR documents in the index.
The newest version!
package de.digitalcollections.solrocr.formats.hocr;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import de.digitalcollections.solrocr.formats.OcrParser;
import de.digitalcollections.solrocr.iter.BreakLocator;
import de.digitalcollections.solrocr.iter.IterableCharSequence;
import de.digitalcollections.solrocr.model.OcrBlock;
import de.digitalcollections.solrocr.model.OcrFormat;
import de.digitalcollections.solrocr.model.OcrPage;
import java.awt.Dimension;
import java.io.Reader;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.xml.stream.XMLStreamException;
import org.apache.commons.lang3.StringUtils;
public class HocrFormat implements OcrFormat {
private static final Pattern pageIdPat =
Pattern.compile(
"(?:id=['\"](?.+?)['\"]|x_source (?.+?)['\";]|ppageno (?\\d+))");
private static final Pattern pageBboxPat =
Pattern.compile("bbox 0 0 (?\\d+) (?\\d+)");
private static final Pattern pageElemPat =
Pattern.compile(".+?)>");
private static final Map> blockClassMapping =
ImmutableMap.>builder()
.put(OcrBlock.PAGE, ImmutableSet.of("ocr_page"))
.put(OcrBlock.BLOCK, ImmutableSet.of("ocr_carea", "ocrx_block"))
.put(
OcrBlock.SECTION,
ImmutableSet.of("ocr_chapter", "ocr_section", "ocr_subsection", "ocr_subsubsection"))
.put(OcrBlock.PARAGRAPH, ImmutableSet.of("ocr_par"))
.put(OcrBlock.LINE, ImmutableSet.of("ocr_line", "ocrx_line"))
.put(OcrBlock.WORD, ImmutableSet.of("ocrx_word"))
.build();
@Override
public BreakLocator getBreakLocator(IterableCharSequence text, OcrBlock... blockTypes) {
List breakClasses =
Arrays.stream(blockTypes)
.flatMap(b -> blockClassMapping.get(b).stream())
.collect(Collectors.toList());
return new HocrClassBreakLocator(text, breakClasses);
}
@Override
public OcrParser getParser(Reader input, OcrParser.ParsingFeature... features) {
try {
return new HocrParser(input, features);
} catch (XMLStreamException e) {
throw new RuntimeException(e);
}
}
@Override
public OcrPage parsePageFragment(String pageFragment) {
// TODO: Might be faster without regexes? Profile!
Matcher m = pageElemPat.matcher(pageFragment);
if (m.find()) {
return parsePage(m.group("attribs"));
}
return null;
}
// TODO: Might be faster without regexes? Profile!
private OcrPage parsePage(String pageAttribs) {
RuntimeException noPageIdExc =
new RuntimeException("Pages must have an identifier, check your source files!");
if (pageAttribs == null) {
throw noPageIdExc;
}
Matcher idMatch = pageIdPat.matcher(pageAttribs);
String pageId = null;
while (idMatch.find()) {
String candidate =
Stream.of("id", "source", "pageno")
.map(idMatch::group)
.filter(StringUtils::isNotEmpty)
.findFirst()
.orElseThrow(() -> noPageIdExc);
if (candidate.equals(idMatch.group("id"))) {
// A specific id is the ideal case, no need to check for further candidates
pageId = candidate;
break;
} else if (candidate.equals(idMatch.group("source"))) {
// A specific source is better than just a page number
pageId = candidate;
} else if (candidate.equals(idMatch.group("pageno")) && pageId == null) {
// Only use a page number if no better candidate was found before
pageId = candidate;
}
}
if (pageId == null) {
throw noPageIdExc;
}
Dimension pageDims = null;
Matcher boxMatch = pageBboxPat.matcher(pageAttribs);
if (boxMatch.find()) {
pageDims =
new Dimension(
Integer.parseInt(boxMatch.group("width")),
Integer.parseInt(boxMatch.group("height")));
}
return new OcrPage(pageId, pageDims);
}
@Override
public boolean hasFormat(String ocrChunk) {
return blockClassMapping.values().stream()
.flatMap(Collection::stream)
.anyMatch(ocrChunk::contains);
}
@Override
public int getLastContentStartIdx(String content) {
return content.lastIndexOf(">") + 1;
}
@Override
public int getFirstContentEndIdx(String content) {
return content.indexOf("