RED-8666

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/LayoutParsingPipeline.java

@@ -10,6 +10,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.pdfbox.Loader;
@@ -26,6 +27,7 @@ import com.knecon.fforesight.service.layoutparser.internal.api.queue.LayoutParsi
 import com.knecon.fforesight.service.layoutparser.processor.model.AbstractPageBlock;
 import com.knecon.fforesight.service.layoutparser.processor.model.ClassificationDocument;
 import com.knecon.fforesight.service.layoutparser.processor.model.ClassificationPage;
+import com.knecon.fforesight.service.layoutparser.processor.model.ClassificationSection;
 import com.knecon.fforesight.service.layoutparser.processor.model.graph.nodes.Document;
 import com.knecon.fforesight.service.layoutparser.processor.model.image.ClassifiedImage;
 import com.knecon.fforesight.service.layoutparser.processor.model.table.CleanRulings;
@@ -47,6 +49,7 @@ import com.knecon.fforesight.service.layoutparser.processor.services.blockificat
 import com.knecon.fforesight.service.layoutparser.processor.services.classification.DocuMineClassificationService;
 import com.knecon.fforesight.service.layoutparser.processor.services.classification.RedactManagerClassificationService;
 import com.knecon.fforesight.service.layoutparser.processor.services.classification.TaasClassificationService;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.DocstrumSegmentationService;
 import com.knecon.fforesight.service.layoutparser.processor.services.factory.DocumentGraphFactory;
 import com.knecon.fforesight.service.layoutparser.processor.services.mapper.DocumentDataMapper;
 import com.knecon.fforesight.service.layoutparser.processor.services.mapper.TaasDocumentDataMapper;
@@ -86,6 +89,7 @@ public class LayoutParsingPipeline {
     RedactManagerBlockificationService redactManagerBlockificationService;
     LayoutGridService layoutGridService;
     ObservationRegistry observationRegistry;
+    DocstrumSegmentationService docstrumSegmentationService;
 
 
     public LayoutParsingFinishedEvent parseLayoutAndSaveFilesToStorage(LayoutParsingRequest layoutParsingRequest) throws IOException {
@@ -243,11 +247,37 @@ public class LayoutParsingPipeline {
             PDRectangle cropbox = pdPage.getCropBox();
             CleanRulings cleanRulings = rulingCleaningService.getCleanRulings(pdfTableCells.get(pageNumber), stripper.getRulings());
 
-            ClassificationPage classificationPage = switch (layoutParsingType) {
-                case REDACT_MANAGER -> redactManagerBlockificationService.blockify(stripper.getTextPositionSequences(), cleanRulings.getHorizontal(), cleanRulings.getVertical());
-                case TAAS -> taasBlockificationService.blockify(stripper.getTextPositionSequences(), cleanRulings.getHorizontal(), cleanRulings.getVertical());
-                case DOCUMINE -> docuMineBlockificationService.blockify(stripper.getTextPositionSequences(), cleanRulings.getHorizontal(), cleanRulings.getVertical());
-            };
+            // Docstrum
+            AtomicInteger num = new AtomicInteger(pageNumber);
+            var zones = docstrumSegmentationService.segmentPage(stripper.getTextPositionSequences());
+
+            List<AbstractPageBlock> pageBlocks = new ArrayList<>();
+            AtomicInteger numOnPage = new AtomicInteger(1);
+//            List<TextPositionSequence> textPositionSequences = new ArrayList<>();
+            zones.forEach(zone -> {
+
+                List<TextPositionSequence> textPositionSequences = new ArrayList<>();
+                zone.getLines().forEach(line -> {
+                    line.getWords().forEach(word -> {
+                        textPositionSequences.add(new TextPositionSequence(word.getTextPositions(), num.get()));
+                    });
+                });
+
+                var cps = redactManagerBlockificationService.blockify(textPositionSequences, cleanRulings.getHorizontal(), cleanRulings.getVertical());
+
+                cps.getTextBlocks().forEach(cp -> {
+                    pageBlocks.add(redactManagerBlockificationService.buildTextBlock(((TextPageBlock) cp).getSequences(), numOnPage.getAndIncrement()));
+                });
+            });
+
+//            ClassificationPage classificationPage = switch (layoutParsingType) {
+//                case REDACT_MANAGER -> redactManagerBlockificationService.blockify(textPositionSequences, cleanRulings.getHorizontal(), cleanRulings.getVertical());
+//                case TAAS -> taasBlockificationService.blockify(textPositionSequences, cleanRulings.getHorizontal(), cleanRulings.getVertical());
+//                case DOCUMINE -> docuMineBlockificationService.blockify(textPositionSequences, cleanRulings.getHorizontal(), cleanRulings.getVertical());
+//            };
+
+            ClassificationPage classificationPage = new ClassificationPage(pageBlocks);
+
             classificationPage.setCleanRulings(cleanRulings);
             classificationPage.setRotation(rotation);
             classificationPage.setLandscape(isLandscape);
@@ -283,9 +313,19 @@ public class LayoutParsingPipeline {
             case REDACT_MANAGER -> redactManagerClassificationService.classifyDocument(classificationDocument);
         }
 
+        List<ClassificationSection> sections = new ArrayList<>();
+        for (var page : classificationPages) {
+            page.getTextBlocks().forEach(block -> {
+                block.setPage(page.getPageNumber());
+                var section = sectionsBuilderService.buildTextBlock(List.of(block), "a");
+                sections.add(section);
+            });
+        }
+        classificationDocument.setSections(sections);
+
         log.info("Building Sections for {}", identifier);
-        sectionsBuilderService.buildSections(classificationDocument);
-        sectionsBuilderService.addImagesToSections(classificationDocument);
+//        sectionsBuilderService.buildSections(classificationDocument);
+//        sectionsBuilderService.addImagesToSections(classificationDocument);
         return classificationDocument;
     }
 

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/model/ClassificationPage.java

@@ -12,15 +12,16 @@ import com.knecon.fforesight.service.layoutparser.processor.model.table.CleanRul
 import com.knecon.fforesight.service.layoutparser.processor.model.text.StringFrequencyCounter;
 
 import lombok.Data;
+import lombok.Getter;
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
-import org.apache.pdfbox.pdmodel.documentinterchange.markedcontent.PDMarkedContent;
 
 @Data
 @RequiredArgsConstructor
 public class ClassificationPage {
 
     @NonNull
+    @Getter
     private List<AbstractPageBlock> textBlocks;
 
     private List<ClassifiedImage> images = new ArrayList<>();

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/model/text/RedTextPosition.java

@@ -45,6 +45,9 @@ public class RedTextPosition {
     @JsonIgnore
     private String fontName;
 
+    @JsonIgnore
+    private RedTextPosition parent;
+
 
     @SneakyThrows
     public static RedTextPosition fromTextPosition(TextPosition textPosition) {

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/model/text/TextPageBlock.java

@@ -17,6 +17,7 @@ import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
+import lombok.Getter;
 import lombok.NoArgsConstructor;
 
 @EqualsAndHashCode(callSuper = true)
@@ -27,6 +28,7 @@ import lombok.NoArgsConstructor;
 public class TextPageBlock extends AbstractPageBlock {
 
     @Builder.Default
+    @Getter
     private List<TextPositionSequence> sequences = new ArrayList<>();
 
     @JsonIgnore
@@ -73,7 +75,7 @@ public class TextPageBlock extends AbstractPageBlock {
 
         return sequences.get(0).getPageWidth();
     }
-    
+
 
     public static TextPageBlock merge(List<TextPageBlock> textBlocksToMerge) {
 
@@ -82,6 +84,7 @@ public class TextPageBlock extends AbstractPageBlock {
         return fromTextPositionSequences(sequences);
     }
 
+
     public static TextPageBlock fromTextPositionSequences(List<TextPositionSequence> wordBlockList) {
 
         TextPageBlock textBlock = null;
@@ -133,7 +136,6 @@ public class TextPageBlock extends AbstractPageBlock {
     }
 
 
-
     /**
      * Returns the minX value in pdf coordinate system.
      * Note: This needs to use Pdf Coordinate System where {0,0} rotated with the page rotation.

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/model/text/TextPositionSequence.java

@@ -55,6 +55,18 @@ public class TextPositionSequence implements CharSequence {
     }
 
 
+    public TextPositionSequence(List<RedTextPosition> textPositions, int page) {
+
+        this.textPositions = textPositions;
+        this.page = page;
+        this.dir = TextDirection.fromDegrees(textPositions.get(0).getDir());
+        this.rotation = textPositions.get(0).getRotation();
+        this.pageHeight = textPositions.get(0).getPageHeight();
+        this.pageWidth = textPositions.get(0).getPageWidth();
+        this.isParagraphStart = false;
+    }
+
+
     @Override
     public int length() {
 

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/SectionsBuilderService.java

@@ -240,7 +240,7 @@ public class SectionsBuilderService {
     }
 
 
-    private ClassificationSection buildTextBlock(List<AbstractPageBlock> wordBlockList, String lastHeadline) {
+    public ClassificationSection buildTextBlock(List<AbstractPageBlock> wordBlockList, String lastHeadline) {
 
         ClassificationSection section = new ClassificationSection();
 

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/blockification/RedactManagerBlockificationService.java

@@ -57,7 +57,7 @@ public class RedactManagerBlockificationService {
             boolean isSplitByRuling = isSplitByRuling(minX, minY, maxX, maxY, word, horizontalRulingLines, verticalRulingLines);
             boolean splitByDir = prev != null && !prev.getDir().equals(word.getDir());
 
-            if (prev != null && (lineSeparation || startFromTop || splitByX || splitByDir || isSplitByRuling)) {
+            if (prev != null && (splitByDir || isSplitByRuling)) {
 
                 Orientation prevOrientation = null;
                 if (!chunkBlockList.isEmpty()) {
@@ -167,7 +167,7 @@ public class RedactManagerBlockificationService {
     }
 
 
-    private TextPageBlock buildTextBlock(List<TextPositionSequence> wordBlockList, int indexOnPage) {
+    public TextPageBlock buildTextBlock(List<TextPositionSequence> wordBlockList, int indexOnPage) {
 
         TextPageBlock textBlock = null;
 

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/DocstrumSegmentationService.java

@@ -0,0 +1,48 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.springframework.stereotype.Service;
+
+import com.knecon.fforesight.service.layoutparser.processor.model.text.TextPositionSequence;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Character;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Zone;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service.LineBuilderService;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service.NearestNeighbourService;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service.ReadingOrderService;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service.SpacingService;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service.ZoneBuilderService;
+
+import lombok.RequiredArgsConstructor;
+
+@Service
+@RequiredArgsConstructor
+public class DocstrumSegmentationService {
+
+    private final NearestNeighbourService nearestNeighbourService;
+    private final SpacingService spacingService;
+    private final LineBuilderService lineBuilderService;
+    private final ZoneBuilderService zoneBuilderService;
+    private final ReadingOrderService readingOrderService;
+
+
+    public List<Zone> segmentPage(List<TextPositionSequence> textPositions) {
+
+        var positions = textPositions.stream().map(TextPositionSequence::getTextPositions).flatMap(List::stream).toList();
+
+        var characters = positions.stream().map(Character::new).collect(Collectors.toList());
+
+        nearestNeighbourService.findNearestNeighbors(characters);
+
+        var characterSpacing = spacingService.computeCharacterSpacing(characters);
+        var lineSpacing = spacingService.computeLineSpacing(characters);
+
+        var lines = lineBuilderService.buildLines(characters, characterSpacing, lineSpacing);
+
+        var zones = zoneBuilderService.buildZones(lines, characterSpacing, lineSpacing);
+
+        return readingOrderService.resolve(zones);
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/AngleFilter.java

@@ -0,0 +1,90 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+/**
+ * Filter class for neighbor objects that checks if the angle of the
+ * neighbor is within specified range.
+ */
+public abstract class AngleFilter {
+
+    private final double lowerAngle;
+    private final double upperAngle;
+
+
+    private AngleFilter(double lowerAngle, double upperAngle) {
+
+        this.lowerAngle = lowerAngle;
+        this.upperAngle = upperAngle;
+    }
+
+
+    /**
+     * Constructs new angle filter.
+     *
+     * @param lowerAngle minimum angle in range [-3*pi/2, pi/2)
+     * @param upperAngle maximum angle in range [-pi/2, 3*pi/2)
+     * @return newly constructed angle filter
+     */
+    public static AngleFilter newInstance(double lowerAngle, double upperAngle) {
+
+        if (lowerAngle < -Math.PI / 2) {
+            lowerAngle += Math.PI;
+        }
+        if (upperAngle >= Math.PI / 2) {
+            upperAngle -= Math.PI;
+        }
+        if (lowerAngle <= upperAngle) {
+            return new AndFilter(lowerAngle, upperAngle);
+        } else {
+            return new OrFilter(lowerAngle, upperAngle);
+        }
+    }
+
+
+    public double getLowerAngle() {
+
+        return lowerAngle;
+    }
+
+
+    public double getUpperAngle() {
+
+        return upperAngle;
+    }
+
+
+    public abstract boolean matches(Neighbor neighbor);
+
+
+    public static final class AndFilter extends AngleFilter {
+
+        private AndFilter(double lowerAngle, double upperAngle) {
+
+            super(lowerAngle, upperAngle);
+        }
+
+
+        @Override
+        public boolean matches(Neighbor neighbor) {
+
+            return getLowerAngle() <= neighbor.getAngle() && neighbor.getAngle() < getUpperAngle();
+        }
+
+    }
+
+    public static final class OrFilter extends AngleFilter {
+
+        private OrFilter(double lowerAngle, double upperAngle) {
+
+            super(lowerAngle, upperAngle);
+        }
+
+
+        @Override
+        public boolean matches(Neighbor neighbor) {
+
+            return getLowerAngle() <= neighbor.getAngle() || neighbor.getAngle() < getUpperAngle();
+        }
+
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/BoundingBox.java

@@ -0,0 +1,48 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import java.awt.geom.Rectangle2D;
+
+import lombok.Data;
+
+@Data
+public abstract class BoundingBox {
+
+    private Rectangle2D bBox;
+
+
+    public double getX() {
+
+        return bBox.getX();
+    }
+
+
+    public double getY() {
+
+        return bBox.getY();
+    }
+
+
+    public double getWidth() {
+
+        return bBox.getWidth();
+    }
+
+
+    public double getHeight() {
+
+        return bBox.getHeight();
+    }
+
+
+    public double getArea() {
+
+        return (bBox.getHeight() * bBox.getWidth());
+    }
+
+
+    public boolean contains(Rectangle2D contained, double tolerance) {
+
+        return bBox.getX() <= contained.getX() + tolerance && bBox.getY() <= contained.getY() + tolerance && bBox.getX() + bBox.getWidth() >= contained.getX() + contained.getWidth() - tolerance && bBox.getY() + bBox.getHeight() >= contained.getY() + contained.getHeight() - tolerance;
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/Character.java

@@ -0,0 +1,69 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.knecon.fforesight.service.layoutparser.processor.model.text.RedTextPosition;
+
+import lombok.Data;
+
+@Data
+public class Character {
+
+    private final double x;
+    private final double y;
+    private final RedTextPosition textPosition;
+
+    private List<Neighbor> neighbors = new ArrayList<>();
+
+
+    public Character(RedTextPosition chunk) {
+
+        this.x = chunk.getXDirAdj() + chunk.getWidthDirAdj() / 2;
+        this.y = chunk.getYDirAdj() + chunk.getHeightDir() / 2;
+        this.textPosition = chunk;
+    }
+
+
+    public double getHeight() {
+
+        return textPosition.getHeightDir();
+    }
+
+
+    public double distance(Character character) {
+
+        double dx = getX() - character.getX();
+        double dy = getY() - character.getY();
+        return Math.sqrt(dx * dx + dy * dy);
+    }
+
+
+    public double horizontalDistance(Character character) {
+
+        return Math.abs(getX() - character.getX());
+    }
+
+
+    public double verticalDistance(Character character) {
+
+        return Math.abs(getY() - character.getY());
+    }
+
+
+    public void setNeighbors(List<Neighbor> neighbors) {
+
+        this.neighbors = neighbors;
+    }
+
+
+    public double angle(Character character) {
+
+        if (getX() > character.getX()) {
+            return Math.atan2(getY() - character.getY(), getX() - character.getX());
+        } else {
+            return Math.atan2(character.getY() - getY(), character.getX() - getX());
+        }
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/DisjointSets.java

@@ -0,0 +1,212 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import java.util.AbstractSet;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+
+public class DisjointSets<E> implements Iterable<Set<E>> {
+
+    private final Map<E, Entry<E>> map = new HashMap<E, Entry<E>>();
+
+
+    /**
+     * Constructs a new set of singletons.
+     *
+     * @param c elements of singleton sets
+     */
+    public DisjointSets(Collection<? extends E> c) {
+
+        for (E element : c) {
+            map.put(element, new Entry<E>(element));
+        }
+    }
+
+
+    /**
+     * Checks if elements are in the same subsets.
+     *
+     * @param e1 element from a subset
+     * @param e2 element from a subset
+     * @return true if elements are in the same subset; false otherwise
+     */
+    public boolean areTogether(E e1, E e2) {
+
+        return map.get(e1).findRepresentative() == map.get(e2).findRepresentative();
+    }
+
+
+    /**
+     * Merges subsets which elements e1 and e2 belong to.
+     *
+     * @param e1 element from a subset
+     * @param e2 element from a subset
+     */
+    public void union(E e1, E e2) {
+
+        Entry<E> r1 = map.get(e1).findRepresentative();
+        Entry<E> r2 = map.get(e2).findRepresentative();
+        if (r1 != r2) {
+            if (r1.size <= r2.size) {
+                r2.mergeWith(r1);
+            } else {
+                r1.mergeWith(r2);
+            }
+        }
+    }
+
+
+    @Override
+    public Iterator<Set<E>> iterator() {
+
+        return new Iterator<Set<E>>() {
+
+            private final Iterator<Entry<E>> iterator = map.values().iterator();
+            private Entry<E> nextRepresentative;
+
+            {
+                findNextRepresentative();
+            }
+
+            @Override
+            public boolean hasNext() {
+
+                return nextRepresentative != null;
+            }
+
+
+            @Override
+            public Set<E> next() {
+
+                if (nextRepresentative == null) {
+                    throw new NoSuchElementException();
+                }
+                Set<E> result = nextRepresentative.asSet();
+                findNextRepresentative();
+                return result;
+            }
+
+
+            private void findNextRepresentative() {
+
+                while (iterator.hasNext()) {
+                    Entry<E> candidate = iterator.next();
+                    if (candidate.isRepresentative()) {
+                        nextRepresentative = candidate;
+                        return;
+                    }
+                }
+                nextRepresentative = null;
+            }
+
+
+            @Override
+            public void remove() {
+
+                throw new UnsupportedOperationException();
+            }
+
+        };
+    }
+
+
+    private static class Entry<E> {
+
+        private int size = 1;
+        private final E value;
+        private Entry<E> parent = this;
+        private Entry<E> next = null;
+        private Entry<E> last = this;
+
+
+        Entry(E value) {
+
+            this.value = value;
+        }
+
+
+        void mergeWith(Entry<E> otherRepresentative) {
+
+            size += otherRepresentative.size;
+            last.next = otherRepresentative;
+            last = otherRepresentative.last;
+            otherRepresentative.parent = this;
+        }
+
+
+        Entry<E> findRepresentative() {
+
+            Entry<E> representative = parent;
+            while (representative.parent != representative) {
+                representative = representative.parent;
+            }
+            for (Entry<E> entry = this; entry != representative; ) {
+                Entry<E> nextEntry = entry.parent;
+                entry.parent = representative;
+                entry = nextEntry;
+            }
+            return representative;
+        }
+
+
+        boolean isRepresentative() {
+
+            return parent == this;
+        }
+
+
+        Set<E> asSet() {
+
+            return new AbstractSet<E>() {
+
+                @Override
+                public Iterator<E> iterator() {
+
+                    return new Iterator<E>() {
+
+                        private Entry<E> nextEntry = findRepresentative();
+
+
+                        @Override
+                        public boolean hasNext() {
+
+                            return nextEntry != null;
+                        }
+
+
+                        @Override
+                        public E next() {
+
+                            if (nextEntry == null) {
+                                throw new NoSuchElementException();
+                            }
+                            E result = nextEntry.value;
+                            nextEntry = nextEntry.next;
+                            return result;
+                        }
+
+
+                        @Override
+                        public void remove() {
+
+                            throw new UnsupportedOperationException();
+                        }
+
+                    };
+                }
+
+
+                @Override
+                public int size() {
+
+                    return findRepresentative().size;
+                }
+            };
+        }
+
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/Histogram.java

@@ -0,0 +1,199 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+public class Histogram implements Iterable<Histogram.Bin> {
+
+    private static final double EPSILON = 1.0e-6;
+
+    private final double min;
+    private final double delta;
+    private final double resolution;
+
+    private double[] frequencies;
+
+
+    /**
+     * Constructs a new histogram for values in range [minValue, maxValue] with
+     * given resolution.
+     *
+     * @param minValue   - minimum allowed value
+     * @param maxValue   - maximum allowed value
+     * @param resolution - histogram's resolution
+     */
+    public Histogram(double minValue, double maxValue, double resolution) {
+
+        this.min = minValue - EPSILON;
+        this.delta = maxValue - minValue + 2 * EPSILON;
+        int size = Math.max(1, (int) Math.round((maxValue - minValue) / resolution));
+        this.resolution = this.delta / size;
+        this.frequencies = new double[size];
+    }
+
+
+    public void kernelSmooth(double[] kernel) {
+
+        double[] newFrequencies = new double[frequencies.length];
+        int shift = (kernel.length - 1) / 2;
+        for (int i = 0; i < kernel.length; i++) {
+            int jStart = Math.max(0, i - shift);
+            int jEnd = Math.min(frequencies.length, frequencies.length + i - shift);
+            for (int j = jStart; j < jEnd; j++) {
+                newFrequencies[j - i + shift] += kernel[i] * frequencies[j];
+            }
+        }
+        frequencies = newFrequencies;
+    }
+
+
+    public void circularKernelSmooth(double[] kernel) {
+
+        double[] newFrequencies = new double[frequencies.length];
+        int shift = (kernel.length - 1) / 2;
+        for (int i = 0; i < frequencies.length; i++) {
+            for (int d = 0; d < kernel.length; d++) {
+                int j = i + d - shift;
+                if (j < 0) {
+                    j += frequencies.length;
+                } else if (j >= frequencies.length) {
+                    j -= frequencies.length;
+                }
+                newFrequencies[i] += kernel[d] * frequencies[j];
+            }
+        }
+        frequencies = newFrequencies;
+    }
+
+
+    public double[] createGaussianKernel(double length, double stdDeviation) {
+
+        int r = (int) Math.round(length / resolution) / 2;
+        stdDeviation /= resolution;
+
+        int size = 2 * r + 1;
+        double[] kernel = new double[size];
+        double sum = 0;
+        double b = 2 * stdDeviation * stdDeviation;
+        double a = 1 / Math.sqrt(Math.PI * b);
+        for (int i = 0; i < size; i++) {
+            kernel[i] = a * Math.exp(-(i - r) * (i - r) / b);
+            sum += kernel[i];
+        }
+        for (int i = 0; i < size; i++) {
+            kernel[i] /= sum;
+        }
+        return kernel;
+    }
+
+
+    public void circularGaussianSmooth(double windowLength, double stdDeviation) {
+
+        circularKernelSmooth(createGaussianKernel(windowLength, stdDeviation));
+    }
+
+
+    public void gaussianSmooth(double windowLength, double stdDeviation) {
+
+        kernelSmooth(createGaussianKernel(windowLength, stdDeviation));
+    }
+
+
+    /**
+     * Adds single occurrence of given value to the histogram.
+     *
+     * @param value inserted values
+     */
+    public void add(double value) {
+
+        frequencies[(int) ((value - min) / resolution)] += 1.0;
+    }
+
+
+    /**
+     * Returns histogram's number of bins.
+     *
+     * @return number of bins
+     */
+    public int getSize() {
+
+        return frequencies.length;
+    }
+
+
+    /**
+     * Finds the histogram's peak value.
+     *
+     * @return peak value
+     */
+    public double getPeakValue() {
+
+        int peakIndex = 0;
+        for (int i = 1; i < frequencies.length; i++) {
+            if (frequencies[i] > frequencies[peakIndex]) {
+                peakIndex = i;
+            }
+        }
+        int peakEndIndex = peakIndex + 1;
+        final double EPS = 0.0001;
+        while (peakEndIndex < frequencies.length && Math.abs(frequencies[peakEndIndex] - frequencies[peakIndex]) < EPS) {
+            peakEndIndex++;
+        }
+        return ((double) peakIndex + peakEndIndex) / 2 * resolution + min;
+    }
+
+
+    @Override
+    public Iterator<Bin> iterator() {
+
+        return new Iterator() {
+
+            private int index = 0;
+
+
+            @Override
+            public boolean hasNext() {
+
+                return index < frequencies.length;
+            }
+
+
+            @Override
+            public Object next() {
+
+                if (index >= frequencies.length) {
+                    throw new NoSuchElementException();
+                }
+                return new Bin(index++);
+            }
+
+
+            @Override
+            public void remove() {
+
+                throw new UnsupportedOperationException("Not supported yet.");
+            }
+
+        };
+    }
+
+
+    public final class Bin {
+
+        private final int index;
+
+
+        private Bin(int index) {
+
+            this.index = index;
+        }
+
+
+        public double getValue() {
+
+            return (index + 0.5) * resolution + min;
+        }
+
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/Line.java

@@ -0,0 +1,167 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import java.awt.geom.Rectangle2D;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import com.knecon.fforesight.service.layoutparser.processor.model.text.TextPositionSequence;
+
+import lombok.Data;
+
+@Data
+public class Line extends BoundingBox {
+
+    private static final double WORD_DISTANCE_MULTIPLIER = 0.2;
+
+    private final double x0;
+    private final double y0;
+
+    private final double x1;
+    private final double y1;
+
+    private final double height;
+
+    private final List<Character> characters;
+    private final List<TextPositionSequence> words = new ArrayList<>();
+
+
+    public Line(List<Character> characters, double wordSpacing) {
+
+        this.characters = characters;
+
+        if (characters.size() >= 2) {
+            // Simple linear regression
+            double sx = 0.0, sxx = 0.0, sxy = 0.0, sy = 0.0;
+            for (Character component : characters) {
+                sx += component.getX();
+                sxx += component.getX() * component.getX();
+                sxy += component.getX() * component.getY();
+                sy += component.getY();
+            }
+            double b = (characters.size() * sxy - sx * sy) / (characters.size() * sxx - sx * sx);
+            double a = (sy - b * sx) / characters.size();
+
+            this.x0 = characters.get(0).getX();
+            this.y0 = a + b * this.x0;
+            this.x1 = characters.get(characters.size() - 1).getX();
+            this.y1 = a + b * this.x1;
+        } else if (!characters.isEmpty()) {
+            Character component = characters.get(0);
+            double dx = component.getTextPosition().getWidthDirAdj() / 3;
+            double dy = dx * Math.tan(0);
+            this.x0 = component.getX() - dx;
+            this.x1 = component.getX() + dx;
+            this.y0 = component.getY() - dy;
+            this.y1 = component.getY() + dy;
+        } else {
+            throw new IllegalArgumentException("Component list must not be empty");
+        }
+        height = computeHeight();
+        computeWords(wordSpacing * WORD_DISTANCE_MULTIPLIER);
+        buildBox();
+    }
+
+
+    public double getAngle() {
+
+        return Math.atan2(y1 - y0, x1 - x0);
+    }
+
+
+    public double getLength() {
+
+        return Math.sqrt((x0 - x1) * (x0 - x1) + (y0 - y1) * (y0 - y1));
+    }
+
+
+    private double computeHeight() {
+
+        double sum = 0.0;
+        for (Character component : characters) {
+            sum += component.getHeight();
+        }
+        return sum / characters.size();
+    }
+
+
+    public double angularDifference(Line j) {
+
+        double diff = Math.abs(getAngle() - j.getAngle());
+        if (diff <= Math.PI / 2) {
+            return diff;
+        } else {
+            return Math.PI - diff;
+        }
+    }
+
+
+    public double horizontalDistance(Line other) {
+
+        double[] xs = new double[4];
+        xs[0] = x0;
+        xs[1] = x1;
+        xs[2] = other.x0;
+        xs[3] = other.x1;
+        boolean overlapping = xs[1] >= xs[2] && xs[3] >= xs[0];
+        Arrays.sort(xs);
+        return Math.abs(xs[2] - xs[1]) * (overlapping ? 1 : -1);
+    }
+
+
+    public double verticalDistance(Line other) {
+
+        double ym = (y0 + y1) / 2;
+        double yn = (other.y0 + other.y1) / 2;
+        return Math.abs(ym - yn) / Math.sqrt(1);
+    }
+
+
+    private void computeWords(double wordSpacing) {
+
+        TextPositionSequence word = new TextPositionSequence();
+        Character previous = null;
+        for (Character current : characters) {
+            if (previous != null) {
+                double dist = current.getTextPosition().getXDirAdj() - previous.getTextPosition().getXDirAdj() - previous.getTextPosition().getWidthDirAdj();
+                if (dist > wordSpacing) {
+                    words.add(word);
+                    word = new TextPositionSequence();
+                }
+            }
+            word.getTextPositions().add(current.getTextPosition());
+            previous = current;
+        }
+        words.add(word);
+    }
+
+
+    private void buildBox() {
+
+        double minX = Double.POSITIVE_INFINITY;
+        double minY = Double.POSITIVE_INFINITY;
+        double maxX = Double.NEGATIVE_INFINITY;
+        double maxY = Double.NEGATIVE_INFINITY;
+
+        for (Character character : characters) {
+
+            minX = Math.min(minX, character.getTextPosition().getXDirAdj());
+            minY = Math.min(minY, character.getTextPosition().getYDirAdj());
+            maxX = Math.max(maxX, character.getTextPosition().getXDirAdj() + character.getTextPosition().getWidthDirAdj());
+            maxY = Math.max(maxY, character.getTextPosition().getYDirAdj() + character.getTextPosition().getHeightDir());
+
+        }
+
+        this.setBBox(new Rectangle2D.Double(minX, minY, maxX - minX, maxY - minY));
+    }
+
+
+    public String toString() {
+
+        StringBuilder sb = new StringBuilder();
+        words.forEach(word -> sb.append(word.toString()).append(" "));
+        return sb.toString().trim();
+    }
+
+}
+

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/Neighbor.java

@@ -0,0 +1,36 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import lombok.Getter;
+
+public class Neighbor {
+
+    @Getter
+    private final double distance;
+    @Getter
+    private final double angle;
+    private final Character originCharacter;
+    @Getter
+    private final Character character;
+
+
+    public Neighbor(Character neighbor, Character origin) {
+
+        this.distance = neighbor.distance(origin);
+        this.angle = neighbor.angle(origin);
+        this.character = neighbor;
+        this.originCharacter = origin;
+    }
+
+
+    public double getHorizontalDistance() {
+
+        return character.horizontalDistance(originCharacter);
+    }
+
+
+    public double getVerticalDistance() {
+
+        return character.verticalDistance(originCharacter);
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/model/Zone.java

@@ -0,0 +1,50 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model;
+
+import java.awt.geom.Rectangle2D;
+import java.util.Comparator;
+import java.util.List;
+
+import lombok.Data;
+
+@Data
+public class Zone extends BoundingBox {
+
+    private List<Line> lines;
+
+
+    public Zone(List<Line> lines) {
+
+        lines.sort(Comparator.comparingDouble(Line::getY));
+        this.lines = lines;
+        buildBox();
+    }
+
+
+    public void buildBox() {
+
+        double minX = Double.POSITIVE_INFINITY;
+        double minY = Double.POSITIVE_INFINITY;
+        double maxX = Double.NEGATIVE_INFINITY;
+        double maxY = Double.NEGATIVE_INFINITY;
+
+        for (Line line : lines) {
+
+            minX = Math.min(minX, line.getX());
+            minY = Math.min(minY, line.getY());
+            maxX = Math.max(maxX, line.getX() + line.getWidth());
+            maxY = Math.max(maxY, line.getY() + line.getHeight());
+
+        }
+
+        this.setBBox(new Rectangle2D.Double(minX, minY, maxX - minX, maxY - minY));
+    }
+
+
+    public String toString() {
+
+        StringBuilder sb = new StringBuilder();
+        lines.forEach(line -> sb.append(line.toString()).append("\n"));
+        return sb.toString().trim();
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/readingorder/BoundingBoxZoneGroup.java

@@ -0,0 +1,64 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder;
+
+import java.awt.geom.Rectangle2D;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.BoundingBox;
+
+public class BoundingBoxZoneGroup extends BoundingBox {
+
+    private BoundingBox leftChild;
+    private BoundingBox rightChild;
+
+
+    public BoundingBoxZoneGroup(BoundingBox child1, BoundingBox child2) {
+
+        this.leftChild = child1;
+        this.rightChild = child2;
+        setBounds(Math.min(child1.getX(), child2.getX()),
+                Math.min(child1.getY(), child2.getY()),
+                Math.max(child1.getX() + child1.getWidth(), child2.getX() + child2.getWidth()),
+                Math.max(child1.getY() + child1.getHeight(), child2.getY() + child2.getHeight()));
+    }
+
+
+    public void setbBox(Rectangle2D bBox) {
+
+        super.setBBox(bBox);
+    }
+
+
+    public BoundingBox getLeftChild() {
+
+        return leftChild;
+    }
+
+
+    public BoundingBox getRightChild() {
+
+        return rightChild;
+    }
+
+
+    public BoundingBoxZoneGroup setLeftChild(BoundingBox obj) {
+
+        this.leftChild = obj;
+        return this;
+    }
+
+
+    public BoundingBoxZoneGroup setRightChild(BoundingBox obj) {
+
+        this.rightChild = obj;
+        return this;
+    }
+
+
+    public BoundingBoxZoneGroup setBounds(double x0, double y0, double x1, double y1) {
+
+        assert x1 >= x0;
+        assert y1 >= y0;
+        this.setBBox(new Rectangle2D.Double(x0, y0, x1 - x0, y1 - y0));
+        return this;
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/readingorder/DistElem.java

@@ -0,0 +1,115 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.utils.DoubleUtils;
+
+public class DistElem<E> implements Comparable<DistElem<E>> {
+
+    @Override
+    public int hashCode() {
+
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + (c ? 1231 : 1237);
+        long temp;
+        temp = Double.doubleToLongBits(dist);
+        result = prime * result + (int) (temp ^ (temp >>> 32));
+        result = prime * result + ((obj1 == null) ? 0 : obj1.hashCode());
+        result = prime * result + ((obj2 == null) ? 0 : obj2.hashCode());
+        return result;
+    }
+
+
+    @Override
+    public boolean equals(Object obj) {
+
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        DistElem other = (DistElem) obj;
+        if (c != other.c) {
+            return false;
+        }
+        if (Double.doubleToLongBits(dist) != Double.doubleToLongBits(other.dist)) {
+            return false;
+        }
+        if (obj1 == null) {
+            if (other.obj1 != null) {
+                return false;
+            }
+        } else if (!obj1.equals(other.obj1)) {
+            return false;
+        }
+        if (obj2 == null) {
+            if (other.obj2 != null) {
+                return false;
+            }
+        } else if (!obj2.equals(other.obj2)) {
+            return false;
+        }
+        return true;
+    }
+
+
+    boolean c;
+    double dist;
+    E obj1;
+    E obj2;
+
+
+    public boolean isC() {
+
+        return c;
+    }
+
+
+    public void setC(boolean c) {
+
+        this.c = c;
+    }
+
+
+    public double getDist() {
+
+        return dist;
+    }
+
+
+    public E getObj1() {
+
+        return obj1;
+    }
+
+
+    public E getObj2() {
+
+        return obj2;
+    }
+
+
+    public DistElem(boolean c, double dist, E obj1, E obj2) {
+
+        this.c = c;
+        this.dist = dist;
+        this.obj1 = obj1;
+        this.obj2 = obj2;
+    }
+
+
+    @Override
+    public int compareTo(DistElem<E> compareObject) {
+
+        double eps = 1E-3;
+        if (c == compareObject.c) {
+            return DoubleUtils.compareDouble(dist, compareObject.dist, eps);
+        } else {
+            return c ? -1 : 1;
+        }
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/readingorder/DocumentPlane.java

@@ -0,0 +1,258 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder;
+
+import java.awt.geom.Rectangle2D;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.BoundingBox;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Zone;
+
+/**
+ * A set-like data structure for objects placed on a plane. Can efficiently find objects in a certain rectangular area.
+ * It maintains two parallel lists of objects, each of which is sorted by its x or y coordinate.
+ *
+ * @author Pawel Szostek
+ */
+public class DocumentPlane {
+
+    /**
+     * List of objects on the plane. Stored in a random order
+     */
+    private final List<BoundingBox> objs;
+    /**
+     * Size of a grid square. If gridSize=50, then the plane is divided into squares of size 50. Each square contains
+     * objects placed in a 50x50 area
+     */
+    private final int gridSize;
+    /**
+     * Redundant dictionary of objects on the plane. Allows efficient 2D space search. Keys are X-Y coordinates of a
+     * grid square. Single object can be stored under several keys (depending on its physical size). Grid squares are
+     * lazy-initialized.
+     */
+    private final Map<GridXY, List<BoundingBox>> grid;
+
+    /**
+     * Representation of XY coordinates
+     */
+    private static class GridXY {
+
+        public int x;
+        public int y;
+
+
+        public GridXY(int x, int y) {
+
+            this.x = x;
+            this.y = y;
+        }
+
+
+        @Override
+        public int hashCode() {
+
+            return x * y;
+        }
+
+
+        @Override
+        public boolean equals(Object obj) {
+
+            if (obj == null || getClass() != obj.getClass()) {
+                return false;
+            }
+            GridXY comparedObj = (GridXY) obj;
+            return x == comparedObj.x && y == comparedObj.y;
+        }
+
+
+        @Override
+        public String toString() {
+
+            return "(" + x + "," + y + ")";
+        }
+
+    }
+
+
+    public List<BoundingBox> getObjects() {
+
+        return objs;
+    }
+
+
+    public DocumentPlane(List<Zone> objectList, int gridSize) {
+
+        this.grid = new HashMap<GridXY, List<BoundingBox>>();
+        this.objs = new ArrayList<BoundingBox>();
+        this.gridSize = gridSize;
+        for (Zone obj : objectList) {
+            add(obj);
+        }
+    }
+
+
+    /**
+     * Looks for objects placed between obj1 and obj2 excluding them
+     *
+     * @param obj1 object
+     * @param obj2 object
+     * @return object list
+     */
+    public List<BoundingBox> findObjectsBetween(BoundingBox obj1, BoundingBox obj2) {
+
+        double x0 = Math.min(obj1.getX(), obj2.getX());
+        double y0 = Math.min(obj1.getY(), obj2.getY());
+        double x1 = Math.max(obj1.getX() + obj1.getWidth(), obj2.getX() + obj2.getWidth());
+        double y1 = Math.max(obj1.getY() + obj1.getHeight(), obj2.getY() + obj2.getHeight());
+        assert x1 >= x0 && y1 >= y0;
+        Rectangle2D searchBounds = new Rectangle2D.Double(x0, y0, x1 - x0, y1 - y0);
+        List<BoundingBox> objsBetween = find(searchBounds);
+        /*
+         * the rectangle area must contain at least obj1 and obj2
+         */
+        objsBetween.remove(obj1);
+        objsBetween.remove(obj2);
+        return objsBetween;
+    }
+
+
+    /**
+     * Checks if there is any object placed between obj1 and obj2
+     *
+     * @param obj1 object
+     * @param obj2 object
+     * @return true if anything is placed between, false otherwise
+     */
+    public boolean anyObjectsBetween(BoundingBox obj1, BoundingBox obj2) {
+
+        List<BoundingBox> lObjs = findObjectsBetween(obj1, obj2);
+        return !(lObjs.isEmpty());
+    }
+
+
+    /**
+     * Adds object to the plane
+     *
+     * @param obj object
+     * @return document plane
+     */
+    public DocumentPlane add(BoundingBox obj) {
+
+        int objsBefore = this.objs.size();
+        /*
+         * iterate over grid squares
+         */
+        for (int y = ((int) obj.getY()) / gridSize; y <= ((int) (obj.getY() + obj.getHeight() + gridSize - 1)) / gridSize; ++y) {
+            for (int x = ((int) obj.getX()) / gridSize; x <= ((int) (obj.getX() + obj.getWidth() + gridSize - 1)) / gridSize; ++x) {
+                GridXY xy = new GridXY(x, y);
+                if (!grid.keySet().contains(xy)) {
+                    /*
+                     * add the non-existing key
+                     */
+                    grid.put(xy, new ArrayList<BoundingBox>());
+                    grid.get(xy).add(obj);
+                    assert grid.get(xy).size() == 1;
+                } else {
+                    grid.get(xy).add(obj);
+                }
+            }
+        }
+        objs.add(obj);
+        /*
+         * size of the object list should be incremented
+         */
+        assert objsBefore + 1 == objs.size();
+        /*
+         * object list must contain the same number of objects as object dictionary
+         */
+        assert objs.size() == elementsInGrid();
+        return this;
+    }
+
+
+    public DocumentPlane remove(BoundingBox obj) {
+        /*
+         * iterate over grid squares
+         */
+        for (int y = ((int) obj.getY()) / gridSize; y <= ((int) (obj.getY() + obj.getHeight() + gridSize - 1)) / gridSize; ++y) {
+            for (int x = ((int) obj.getX()) / gridSize; x <= ((int) (obj.getX() + obj.getWidth() + gridSize - 1)) / gridSize; ++x) {
+                GridXY xy = new GridXY(x, y);
+                if (grid.get(xy).contains(obj)) {
+                    grid.get(xy).remove(obj);
+                }
+            }
+        }
+        objs.remove(obj);
+        assert objs.size() == elementsInGrid();
+        return this;
+    }
+
+
+    /**
+     * Find objects within search bounds
+     *
+     * @param searchBounds is a search rectangle
+     * @return list of objects in!side search rectangle
+     */
+    public List<BoundingBox> find(Rectangle2D searchBounds) {
+
+        List<BoundingBox> done = new ArrayList<BoundingBox>(); //contains already considered objects (wrt. optimization)
+        List<BoundingBox> ret = new ArrayList<BoundingBox>();
+        double x0 = searchBounds.getX();
+        double y0 = searchBounds.getY();
+        double y1 = searchBounds.getY() + searchBounds.getHeight();
+        double x1 = searchBounds.getX() + searchBounds.getWidth();
+        /*
+         * iterate over grid squares
+         */
+        for (int y = (int) y0 / gridSize; y < ((int) (y1 + gridSize - 1)) / gridSize; ++y) {
+            for (int x = (int) x0 / gridSize; x < ((int) (x1 + gridSize - 1)) / gridSize; ++x) {
+                GridXY xy = new GridXY(x, y);
+                if (!grid.containsKey(xy)) {
+                    continue;
+                }
+                for (BoundingBox obj : grid.get(xy)) {
+                    if (done.contains(obj)) /*
+                     * omit if already checked
+                     */ {
+                        continue;
+                    }
+                    /*
+                     * add to the checked objects
+                     */
+                    done.add(obj);
+                    /*
+                     * check if two objects overlap
+                     */
+                    if (obj.getX() + obj.getWidth() <= x0 || x1 <= obj.getX() || obj.getY() + obj.getHeight() <= y0 || y1 <= obj.getY()) {
+                        continue;
+                    }
+                    ret.add(obj);
+                }
+            }
+        }
+        return ret;
+    }
+
+
+    /**
+     * Count objects stored in objects dictionary
+     *
+     * @return number of elements
+     */
+    protected int elementsInGrid() {
+
+        List<BoundingBox> objs_ = new ArrayList<BoundingBox>();
+        for (GridXY coord : grid.keySet()) {
+            for (BoundingBox obj : grid.get(coord)) {
+                if (!objs_.contains(obj)) {
+                    objs_.add(obj);
+                }
+            }
+        }
+        return objs_.size();
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/readingorder/TreeToListConverter.java

@@ -0,0 +1,29 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Zone;
+
+public class TreeToListConverter {
+
+    public List<Zone> convertToList(BoundingBoxZoneGroup obj) {
+
+        List<Zone> ret = new ArrayList<>();
+        if (obj.getLeftChild() instanceof Zone) {
+            Zone zone = (Zone) obj.getLeftChild();
+            ret.add(zone);
+        } else { // obj.getLeftChild() instanceof BxZoneGroup
+            ret.addAll(convertToList((BoundingBoxZoneGroup) obj.getLeftChild()));
+        }
+
+        if (obj.getRightChild() instanceof Zone) {
+            Zone zone = (Zone) obj.getRightChild();
+            ret.add(zone);
+        } else { // obj.getRightChild() instanceof BxZoneGroup
+            ret.addAll(convertToList((BoundingBoxZoneGroup) obj.getRightChild()));
+        }
+        return ret;
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/service/LineBuilderService.java

@@ -0,0 +1,50 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.AngleFilter;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Character;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.DisjointSets;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Line;
+
+@Service
+public class LineBuilderService {
+
+    private static final double CHARACTER_SPACING_DISTANCE_MULTIPLIER = 3.5;
+    private static final double MAX_VERTICAL_CHARACTER_DISTANCE = 0.67;
+    private static final double ANGLE_TOLERANCE = Math.PI / 6;
+
+
+    public List<Line> buildLines(List<Character> characters, double characterSpacing, double lineSpacing) {
+
+        double maxHorizontalDistance = characterSpacing * CHARACTER_SPACING_DISTANCE_MULTIPLIER;
+        double maxVerticalDistance = lineSpacing * MAX_VERTICAL_CHARACTER_DISTANCE;
+
+        DisjointSets<Character> sets = new DisjointSets<>(characters);
+        AngleFilter filter = AngleFilter.newInstance(-ANGLE_TOLERANCE, ANGLE_TOLERANCE);
+
+        characters.forEach(character -> {
+            character.getNeighbors().forEach(neighbor -> {
+                double x = neighbor.getHorizontalDistance() / maxHorizontalDistance;
+                double y = neighbor.getVerticalDistance() / maxVerticalDistance;
+                if (filter.matches(neighbor) && Math.pow(x, 2) + Math.pow(y, 2) <= 1) {
+                    sets.union(character, neighbor.getCharacter());
+                }
+            });
+        });
+
+        List<Line> lines = new ArrayList<>();
+        sets.forEach(group -> {
+            List<Character> lineComponents = new ArrayList<>(group);
+            lineComponents.sort(Comparator.comparingDouble(Character::getX));
+            lines.add(new Line(lineComponents, characterSpacing));
+        });
+
+        return lines;
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/service/NearestNeighbourService.java

@@ -0,0 +1,78 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Character;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Neighbor;
+
+@Service
+public class NearestNeighbourService {
+
+    private static final int NUMBER_OF_NEIGHBOURS = 8;
+    private static final double STEP = 16.0;
+
+
+    public void findNearestNeighbors(List<Character> characters) {
+
+        if (characters.isEmpty()) {
+            return;
+        }
+
+        characters.sort(Comparator.comparingDouble(Character::getX));
+
+        int maxNeighborCount = NUMBER_OF_NEIGHBOURS;
+        if (characters.size() <= NUMBER_OF_NEIGHBOURS) {
+            maxNeighborCount = characters.size() - 1;
+        }
+
+        for (int i = 0; i < characters.size(); i++) {
+
+            List<Neighbor> candidates = new ArrayList<>();
+
+            int start = i;
+            int end = i + 1;
+
+            double distance = Double.POSITIVE_INFINITY;
+
+            for (double searchDistance = 0; searchDistance < distance; ) {
+
+                searchDistance += STEP;
+                boolean newCandidatesFound = false;
+
+                while (start > 0 && characters.get(i).getX() - characters.get(start - 1).getX() < searchDistance) {
+                    start--;
+                    candidates.add(new Neighbor(characters.get(start), characters.get(i)));
+                    clearLeastDistant(candidates, maxNeighborCount);
+                    newCandidatesFound = true;
+                }
+
+                while (end < characters.size() && characters.get(end).getX() - characters.get(i).getX() < searchDistance) {
+                    candidates.add(new Neighbor(characters.get(end), characters.get(i)));
+                    clearLeastDistant(candidates, maxNeighborCount);
+                    end++;
+                    newCandidatesFound = true;
+                }
+
+                if (newCandidatesFound && candidates.size() >= maxNeighborCount) {
+                    distance = candidates.get(maxNeighborCount - 1).getDistance();
+                }
+            }
+            clearLeastDistant(candidates, maxNeighborCount);
+            characters.get(i).setNeighbors(new ArrayList<>(candidates));
+        }
+    }
+
+
+    private void clearLeastDistant(List<Neighbor> candidates, int maxNeighborCount) {
+
+        if (candidates.size() > maxNeighborCount) {
+            candidates.sort(Comparator.comparingDouble(Neighbor::getDistance));
+            candidates.remove(candidates.remove(candidates.size() - 1));
+        }
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/service/ReadingOrderService.java

@@ -0,0 +1,286 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.BoundingBox;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Zone;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder.BoundingBoxZoneGroup;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder.DistElem;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder.DocumentPlane;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.readingorder.TreeToListConverter;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.utils.DoubleUtils;
+
+@Service
+public class ReadingOrderService {
+
+    static final int GRIDSIZE = 50;
+    static final double EPS = 0.01;
+    static final int MAX_ZONES = 1000;
+    static final Comparator<BoundingBox> Y_ASCENDING_ORDER = new Comparator<BoundingBox>() {
+
+        @Override
+        public int compare(BoundingBox o1, BoundingBox o2) {
+
+            return DoubleUtils.compareDouble(o1.getY(), o2.getY(), EPS);
+        }
+    };
+
+    static final Comparator<BoundingBox> X_ASCENDING_ORDER = new Comparator<BoundingBox>() {
+
+        @Override
+        public int compare(BoundingBox o1, BoundingBox o2) {
+
+            return DoubleUtils.compareDouble(o1.getX(), o2.getX(), EPS);
+        }
+    };
+
+    static final Comparator<BoundingBox> YX_ASCENDING_ORDER = new Comparator<BoundingBox>() {
+
+        @Override
+        public int compare(BoundingBox o1, BoundingBox o2) {
+
+            int yCompare = Y_ASCENDING_ORDER.compare(o1, o2);
+            return yCompare == 0 ? X_ASCENDING_ORDER.compare(o1, o2) : yCompare;
+        }
+    };
+
+
+    public List<Zone> resolve(List<Zone> zones) {
+
+        List<Zone> orderedZones;
+        if (zones.size() > MAX_ZONES) {
+            orderedZones = new ArrayList<>(zones);
+            Collections.sort(orderedZones, YX_ASCENDING_ORDER);
+        } else {
+            orderedZones = reorderZones(zones);
+        }
+        return orderedZones;
+    }
+
+
+    private List<Zone> reorderZones(List<Zone> unorderedZones) {
+
+        if (unorderedZones.isEmpty()) {
+            return new ArrayList<>();
+        } else if (unorderedZones.size() == 1) {
+            List<Zone> ret = new ArrayList<>(1);
+            ret.add(unorderedZones.get(0));
+            return ret;
+        } else {
+            BoundingBoxZoneGroup bxZonesTree = groupZonesHierarchically(unorderedZones);
+            sortGroupedZones(bxZonesTree);
+            TreeToListConverter treeConverter = new TreeToListConverter();
+            List<Zone> orderedZones = treeConverter.convertToList(bxZonesTree);
+            assert unorderedZones.size() == orderedZones.size();
+            return orderedZones;
+        }
+    }
+
+
+    /**
+     * Builds a binary tree of zones and groups of zones from a list of unordered zones. This is done in hierarchical
+     * clustering by joining two least distant nodes. Distance is calculated in the distance() method.
+     *
+     * @param zones is a list of unordered zones
+     * @return root of the zones clustered in a tree
+     */
+    private BoundingBoxZoneGroup groupZonesHierarchically(List<Zone> zones) {
+        /*
+         * Distance tuples are stored sorted by ascending distance value
+         */
+        List<DistElem<BoundingBox>> dists = new ArrayList<DistElem<BoundingBox>>(zones.size() * zones.size() / 2);
+        for (int idx1 = 0; idx1 < zones.size(); ++idx1) {
+            for (int idx2 = idx1 + 1; idx2 < zones.size(); ++idx2) {
+                Zone zone1 = zones.get(idx1);
+                Zone zone2 = zones.get(idx2);
+                dists.add(new DistElem<BoundingBox>(false, distance(zone1, zone2), zone1, zone2));
+            }
+        }
+        Collections.sort(dists);
+        DocumentPlane plane = new DocumentPlane(zones, GRIDSIZE);
+        while (!dists.isEmpty()) {
+            DistElem<BoundingBox> distElem = dists.get(0);
+            dists.remove(0);
+            if (!distElem.isC() && plane.anyObjectsBetween(distElem.getObj1(), distElem.getObj2())) {
+                dists.add(new DistElem<BoundingBox>(true, distElem.getDist(), distElem.getObj1(), distElem.getObj2()));
+                continue;
+            }
+            BoundingBoxZoneGroup newGroup = new BoundingBoxZoneGroup(distElem.getObj1(), distElem.getObj2());
+            plane.remove(distElem.getObj1()).remove(distElem.getObj2());
+            dists = removeDistElementsContainingObject(dists, distElem.getObj1());
+            dists = removeDistElementsContainingObject(dists, distElem.getObj2());
+            for (BoundingBox other : plane.getObjects()) {
+                dists.add(new DistElem<BoundingBox>(false, distance(other, newGroup), newGroup, other));
+            }
+            Collections.sort(dists);
+            plane.add(newGroup);
+        }
+
+        assert plane.getObjects().size() == 1 : "There should be one object left at the plane after grouping";
+        return (BoundingBoxZoneGroup) plane.getObjects().get(0);
+    }
+
+
+    /**
+     * Removes all distance tuples containing obj
+     */
+    private List<DistElem<BoundingBox>> removeDistElementsContainingObject(Collection<DistElem<BoundingBox>> list, BoundingBox obj) {
+
+        List<DistElem<BoundingBox>> ret = new ArrayList<DistElem<BoundingBox>>();
+        for (DistElem<BoundingBox> distElem : list) {
+            if (distElem.getObj1() != obj && distElem.getObj2() != obj) {
+                ret.add(distElem);
+            }
+        }
+        return ret;
+    }
+
+
+    /**
+     * Swaps children of BxZoneGroup if necessary. A group with smaller sort factor is placed to the left (leftChild).
+     * An object with greater sort factor is placed on the right (rightChild). This plays an important role when
+     * traversing the tree in conversion to a one dimensional list.
+     *
+     * @param group
+     */
+    private void sortGroupedZones(BoundingBoxZoneGroup group) {
+
+        BoundingBox leftChild = group.getLeftChild();
+        BoundingBox rightChild = group.getRightChild();
+        if (shouldBeSwapped(leftChild, rightChild)) {
+            // swap
+            group.setLeftChild(rightChild);
+            group.setRightChild(leftChild);
+        }
+
+        if (leftChild instanceof BoundingBoxZoneGroup) // if the child is a tree node, then recurse
+        {
+            sortGroupedZones((BoundingBoxZoneGroup) leftChild);
+        }
+        if (rightChild instanceof BoundingBoxZoneGroup) // as above - recurse
+        {
+            sortGroupedZones((BoundingBoxZoneGroup) rightChild);
+        }
+    }
+
+
+    private boolean shouldBeSwapped(BoundingBox first, BoundingBox second) {
+
+        double cx, cy, cw, ch, ox, oy, ow, oh;
+        cx = first.getBBox().getX();
+        cy = first.getBBox().getY();
+        cw = first.getBBox().getWidth();
+        ch = first.getBBox().getHeight();
+
+        ox = second.getBBox().getX();
+        oy = second.getBBox().getY();
+        ow = second.getBBox().getWidth();
+        oh = second.getBBox().getHeight();
+
+        // Determine Octant
+        //
+        // 0 | 1 | 2
+        // __|___|__
+        // 7 | 9 | 3   First is placed in 9th square
+        // __|___|__
+        // 6 | 5 | 4
+
+        if (cx + cw <= ox) { //2,3,4
+            return false;
+        } else if (ox + ow <= cx) { //0,6,7
+            return true; //6
+        } else if (cy + ch <= oy) {
+            return false; //5
+        } else if (oy + oh <= cy) {
+            return true; //1
+        } else { //two zones
+            double xdiff = ox + ow / 2 - cx - cw / 2;
+            double ydiff = oy + oh / 2 - cy - ch / 2;
+            return xdiff + ydiff < 0;
+        }
+    }
+
+
+    /**
+     * A distance function between two TextBoxes.
+     * <p>
+     * Consider the bounding rectangle for obj1 and obj2. Return its area minus the areas of obj1 and obj2, shown as
+     * 'www' below. This value may be negative. (x0,y0) +------+..........+ | obj1 |wwwwwwwwww: +------+www+------+
+     * :wwwwwwwwww| obj2 | +..........+------+ (x1,y1)
+     *
+     * @return distance value based on objects' coordinates and physical size on a plane
+     */
+    private double distance(BoundingBox obj1, BoundingBox obj2) {
+
+        double x0 = Math.min(obj1.getX(), obj2.getX());
+        double y0 = Math.min(obj1.getY(), obj2.getY());
+        double x1 = Math.max(obj1.getX() + obj1.getWidth(), obj2.getX() + obj2.getWidth());
+        double y1 = Math.max(obj1.getY() + obj1.getHeight(), obj2.getY() + obj2.getHeight());
+        double dist = ((x1 - x0) * (y1 - y0) - obj1.getArea() - obj2.getArea());
+
+        double factor = ((x1 - x0)/x1) / ((y1 - y0)/y1);
+
+        double obj1X = obj1.getX();
+        double obj1Y_2 = obj1.getBBox().getMaxY();
+        double obj1X_2 = obj1.getBBox().getMaxX();
+        double obj1CenterX = obj1.getBBox().getCenterX();
+        double obj1CenterY = obj1.getBBox().getCenterY();
+        double obj2X = obj2.getX();
+        double obj2Y_2 = obj2.getBBox().getMaxY();
+        double obj2X_2 = obj2.getBBox().getMaxX();
+        double obj2CenterX = obj2.getBBox().getCenterX();
+        double obj2CenterY = obj2.getBBox().getCenterY();
+
+        double obj1obj2VectorCosineAbsLeft = Math.abs((obj2X - obj1X) / Math.sqrt((obj2X - obj1X) * (obj2X - obj1X) + (obj2CenterY - obj1CenterY) * (obj2CenterY - obj1CenterY)));
+        double obj1obj2VectorCosineAbsRight = Math.abs((obj2X_2 - obj1X_2) / Math.sqrt((obj2X_2 - obj1X_2) * (obj2X_2 - obj1X_2) + (obj2CenterY - obj1CenterY) * (obj2CenterY - obj1CenterY)));
+        double obj1obj2VectorCosineAbsCenter = Math.abs((obj2CenterX - obj1CenterX) / Math.sqrt((obj2CenterX - obj1CenterX) * (obj2CenterX - obj1CenterX) + (obj2CenterY - obj1CenterY) * (obj2CenterY - obj1CenterY)));
+
+        double cosine = Math.min(obj1obj2VectorCosineAbsLeft, Math.min(obj1obj2VectorCosineAbsRight, obj1obj2VectorCosineAbsCenter));
+
+        final double MAGIC_COEFF = 0.85;
+        //return dist * (MAGIC_COEFF + cosine);
+
+        return Math.sqrt(Math.pow((obj1X - obj2X), 2) + Math.pow((obj1Y_2 - obj2Y_2) * MAGIC_COEFF, 2));
+
+
+        /**if (Math.abs(obj1CenterX - obj2CenterX) >= Math.abs(obj1CenterY - obj2CenterY)) {
+            return dist * 2;
+        } else {
+            return dist;
+        }**/
+
+
+    }
+
+
+    private double distanceNew(BoundingBox obj1, BoundingBox obj2) {
+
+        if(obj1.getBBox().intersects(obj2.getBBox()))
+            return -1;
+
+        double minX0 = Math.min(obj1.getX(), obj2.getX());
+        double maxX0 = Math.max(obj1.getX(), obj2.getX());
+        double minY0 = Math.min(obj1.getY(), obj2.getY());
+        double maxY0 = Math.max(obj1.getY(), obj2.getY());
+        double minX1 = Math.min(obj1.getX() + obj1.getWidth(), obj2.getX() + obj2.getWidth());
+        double maxX1 = Math.max(obj1.getX() + obj1.getWidth(), obj2.getX() + obj2.getWidth());
+        double minY1 = Math.min(obj1.getY() + obj1.getHeight(), obj2.getY() + obj2.getHeight());
+        double maxY1 = Math.max(obj1.getY() + obj1.getHeight(), obj2.getY() + obj2.getHeight());
+        List<Double> xValues = new ArrayList<>(List.of(minX0, maxX0, minX1, maxX1));
+        Collections.sort(xValues);
+        List<Double> yValues = new ArrayList<>(List.of(minY0, maxY0, minY1, maxY1));
+        Collections.sort(yValues);
+
+        double yArea = (xValues.get(2) - xValues.get(1)) * (yValues.get(3) - yValues.get(0));
+        double xArea = (yValues.get(2) - yValues.get(1)) * (xValues.get(3) - xValues.get(0));
+
+        return Math.min(10*yArea, xArea);
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/service/SpacingService.java

@@ -0,0 +1,56 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service;
+
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.AngleFilter;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Character;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Histogram;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Neighbor;
+
+@Service
+public class SpacingService {
+
+    private static final double SPACING_HISTOGRAM_RESOLUTION = 0.5;
+    private static final double SPACING_HISTOGRAM_SMOOTHING_LENGTH = 2.5;
+    private static final double SPACING_HIST_SMOOTHING_STANDARD_DEVIATION = 0.5;
+    private static final double ANGLE_TOLERANCE = Math.PI / 6;
+
+
+    public double computeCharacterSpacing(List<Character> components) {
+
+        return computeSpacing(components, 0);
+    }
+
+
+    public double computeLineSpacing(List<Character> components) {
+
+        return computeSpacing(components, Math.PI / 2);
+    }
+
+
+    private double computeSpacing(List<Character> components, double angle) {
+
+        double maxDistance = Double.NEGATIVE_INFINITY;
+
+        for (Character component : components) {
+            for (Neighbor neighbor : component.getNeighbors()) {
+                maxDistance = Math.max(maxDistance, neighbor.getDistance());
+            }
+        }
+        Histogram histogram = new Histogram(0, maxDistance, SPACING_HISTOGRAM_RESOLUTION);
+        AngleFilter filter = AngleFilter.newInstance(angle - ANGLE_TOLERANCE, angle + ANGLE_TOLERANCE);
+        for (Character component : components) {
+            for (Neighbor neighbor : component.getNeighbors()) {
+                if (filter.matches(neighbor)) {
+                    histogram.add(neighbor.getDistance());
+                }
+            }
+        }
+
+        histogram.gaussianSmooth(SPACING_HISTOGRAM_SMOOTHING_LENGTH, SPACING_HIST_SMOOTHING_STANDARD_DEVIATION);
+        return histogram.getPeakValue();
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/service/ZoneBuilderService.java

@@ -0,0 +1,94 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.DisjointSets;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Line;
+import com.knecon.fforesight.service.layoutparser.processor.services.docstrum.model.Zone;
+
+@Service
+public class ZoneBuilderService {
+
+    private static final double MIN_HORIZONTAL_DISTANCE_MULTIPLIER = -0.5;
+    private static final double MAX_VERTICAL_DISTANCE_MULTIPLIER = 1.2;
+
+    private static final double MIN_HORIZONTAL_MERGE_DISTANCE_MULTIPLIER = -3.0;
+
+    private static final double MAX_VERTICAL_MERGE_DISTANCE_MULTIPLIER = 0.5;
+
+    private static final double MIN_LINE_SIZE_SCALE = 0.9;
+
+    private static final double MAX_LINE_SIZE_SCALE = 2.5;
+
+    private static final double ANGLE_TOLERANCE = Math.PI / 6;
+
+    public static final int MAX_ZONES = 300;
+
+
+    public List<Zone> buildZones(List<Line> lines, double characterSpacing, double lineSpacing) {
+
+        double minHorizontalDistance = characterSpacing * MIN_HORIZONTAL_DISTANCE_MULTIPLIER;
+        double maxVerticalDistance = lineSpacing * MAX_VERTICAL_DISTANCE_MULTIPLIER;
+        double minHorizontalMergeDistance = characterSpacing * MIN_HORIZONTAL_MERGE_DISTANCE_MULTIPLIER;
+        double maxVerticalMergeDistance = lineSpacing * MAX_VERTICAL_MERGE_DISTANCE_MULTIPLIER;
+
+        DisjointSets<Line> sets = new DisjointSets<>(lines);
+
+        double meanHeight = calculateMeanHeight(lines);
+
+        lines.forEach(outerLine -> //
+                lines.forEach(innerLine -> {
+                    double scale = Math.min(outerLine.getHeight(), innerLine.getHeight()) / meanHeight;
+                    scale = Math.max(MIN_LINE_SIZE_SCALE, Math.min(scale, MAX_LINE_SIZE_SCALE));
+
+                    if (!sets.areTogether(outerLine, innerLine) && outerLine.angularDifference(innerLine) <= ANGLE_TOLERANCE) {
+
+                        double horizontalDistance = outerLine.horizontalDistance(innerLine) / scale;
+                        double verticalDistance = outerLine.verticalDistance(innerLine) / scale;
+
+                        // Line over or above
+                        if (minHorizontalDistance <= horizontalDistance && verticalDistance <= maxVerticalDistance) {
+                            sets.union(outerLine, innerLine);
+                        }
+
+                        // Split line that needs later merging
+                        else if (minHorizontalMergeDistance <= horizontalDistance && verticalDistance <= maxVerticalMergeDistance) {
+                            sets.union(outerLine, innerLine);
+                        }
+                    }
+                }));
+
+        List<Zone> zones = new ArrayList<>();
+        sets.forEach(group -> {
+            zones.add(new Zone(new ArrayList<>(group)));
+        });
+
+        if (zones.size() > MAX_ZONES) {
+            List<Line> oneZoneLines = new ArrayList<>();
+            for (Zone zone : zones) {
+                oneZoneLines.addAll(zone.getLines());
+            }
+            return List.of(new Zone(oneZoneLines));
+        }
+
+        return zones;
+    }
+
+
+    private double calculateMeanHeight(List<Line> lines) {
+
+        double meanHeight = 0.0;
+        double weights = 0.0;
+        for (Line line : lines) {
+            double weight = line.getLength();
+            meanHeight += line.getHeight() * weight;
+            weights += weight;
+        }
+        meanHeight /= weights;
+        return meanHeight;
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/docstrum/utils/DoubleUtils.java

@@ -0,0 +1,18 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.docstrum.utils;
+
+public class DoubleUtils {
+
+    public static int compareDouble(double d1, double d2, double precision) {
+
+        if (Double.isNaN(d1) || Double.isNaN(d2)) {
+            return Double.compare(d1, d2);
+        }
+        if (precision == 0) {
+            precision = 1;
+        }
+        long i1 = Math.round(d1 / precision);
+        long i2 = Math.round(d2 / precision);
+        return Long.valueOf(i1).compareTo(i2);
+    }
+
+}

layoutparser-service/layoutparser-service-processor/src/main/java/com/knecon/fforesight/service/layoutparser/processor/services/visualization/PdfDraw.java

@@ -0,0 +1,270 @@
+package com.knecon.fforesight.service.layoutparser.processor.services.visualization;
+
+import java.awt.Color;
+import java.awt.geom.Point2D;
+import java.awt.geom.Rectangle2D;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.pdfbox.Loader;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.font.PDType1Font;
+import org.apache.pdfbox.pdmodel.font.Standard14Fonts;
+import org.apache.pdfbox.util.Matrix;
+import org.springframework.core.io.ClassPathResource;
+
+import com.knecon.fforesight.service.layoutparser.internal.api.data.redaction.NodeType;
+import com.knecon.fforesight.service.layoutparser.processor.model.graph.DocumentTree;
+import com.knecon.fforesight.service.layoutparser.processor.model.graph.nodes.Document;
+import com.knecon.fforesight.service.layoutparser.processor.model.graph.nodes.Page;
+import com.knecon.fforesight.service.layoutparser.processor.model.graph.textblock.AtomicTextBlock;
+import com.knecon.fforesight.service.layoutparser.processor.model.graph.textblock.TextBlock;
+import com.knecon.fforesight.service.layoutparser.processor.model.table.Ruling;
+import com.knecon.fforesight.service.layoutparser.processor.utils.PdfVisualisationUtility;
+import com.knecon.fforesight.service.layoutparser.processor.utils.RectangleTransformations;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.SneakyThrows;
+import lombok.experimental.FieldDefaults;
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class PdfDraw {
+
+    public static void drawRectanglesPerPage(String filename, List<List<Rectangle2D>> rectanglesPerPage, String tmpFileName) throws IOException {
+
+        ClassPathResource pdfResource = new ClassPathResource(filename);
+        try (PDDocument pdDocument = Loader.loadPDF(pdfResource.getFile()); var out = new FileOutputStream(tmpFileName)) {
+            for (int pageNumber = 1; pageNumber < pdDocument.getNumberOfPages() + 1; pageNumber++) {
+                PdfVisualisationUtility.drawRectangle2DList(pdDocument,
+                        pageNumber,
+                        rectanglesPerPage.get(pageNumber - 1),
+                        PdfVisualisationUtility.Options.builder().stroke(true).build());
+            }
+            pdDocument.save(out);
+        }
+
+    }
+
+
+    public static void drawRectanglesPerPageNumberedByLine(String filename, List<List<List<Rectangle2D>>> rectanglesPerPage, String tmpFileName) throws IOException {
+
+        ClassPathResource pdfResource = new ClassPathResource(filename);
+        try (PDDocument pdDocument = Loader.loadPDF(pdfResource.getFile()); var out = new FileOutputStream(tmpFileName)) {
+            for (int pageNumber = 1; pageNumber < pdDocument.getNumberOfPages() + 1; pageNumber++) {
+                var rectanglesOnPage = rectanglesPerPage.get(pageNumber - 1);
+                for (int lineNumber = 0; lineNumber < rectanglesOnPage.size(); lineNumber++) {
+                    var rectanglesInLine = rectanglesOnPage.get(lineNumber);
+                    PdfVisualisationUtility.drawRectangle2DList(pdDocument, pageNumber, rectanglesInLine, PdfVisualisationUtility.Options.builder().stroke(true).build());
+                    double y = Math.min(rectanglesInLine.get(0).getMinY(), rectanglesInLine.get(0).getMaxY());
+                    PdfVisualisationUtility.drawText(String.format("%d", lineNumber),
+                            pdDocument,
+                            new Point2D.Double(rectanglesInLine.get(0).getX() - (5 + (5 * countNumberOfDigits(lineNumber))), y + 2),
+                            pageNumber,
+                            PdfVisualisationUtility.Options.builder().stroke(true).build());
+                }
+            }
+            pdDocument.save(out);
+        }
+
+    }
+
+
+    private static int countNumberOfDigits(int num) {
+
+        int final_num = num;
+        if (final_num == 0) {
+            return 1;
+        }
+        int count = 0;
+        for (; final_num != 0; final_num /= 10) {
+            count++;
+        }
+        return count;
+    }
+
+
+    public static void drawDocumentGraph(PDDocument document, Document documentGraph) {
+
+        documentGraph.getDocumentTree().allEntriesInOrder().forEach(entry -> drawNode(document, entry));
+    }
+
+
+    public static void drawNode(PDDocument document, DocumentTree.Entry entry) {
+
+        Options options = buildStandardOptionsForNodes(entry);
+
+        drawBBoxAndLabelAndNumberOnPage(document, entry, options);
+
+    }
+
+
+    public static void drawTextBlock(PDDocument document, TextBlock textBlock, Options options) {
+
+        textBlock.getAtomicTextBlocks().forEach(atb -> drawAtomicTextBlock(document, atb, options));
+    }
+
+
+    public static void drawAtomicTextBlock(PDDocument document, AtomicTextBlock atomicTextBlock, Options options) {
+
+        drawRectangle2DList(document, atomicTextBlock.getPage().getNumber(), atomicTextBlock.getPositions().stream().toList(), options);
+
+    }
+
+
+    @SneakyThrows
+    private static void drawText(String string, PDDocument document, Point2D location, Integer pageNumber, Options options, boolean rotate) {
+
+        var pdPage = document.getPage(pageNumber - 1);
+        var contentStream = new PDPageContentStream(document, pdPage, PDPageContentStream.AppendMode.APPEND, true);
+
+        contentStream.setNonStrokingColor(options.getStrokeColor());
+        contentStream.setLineWidth(options.getStrokeWidth());
+
+        contentStream.beginText();
+        if (rotate) {
+            contentStream.setTextMatrix(Matrix.getRotateInstance(Math.toRadians(15), (float) location.getX(), (float) location.getY()));
+        } else {
+            contentStream.newLineAtOffset((float) location.getX(), (float) location.getY());
+        }
+        contentStream.setFont(new PDType1Font(Standard14Fonts.FontName.HELVETICA), 10);
+        contentStream.showText(string);
+        contentStream.endText();
+        contentStream.close();
+    }
+
+
+    @SneakyThrows
+    public static void drawRectangle2DList(PDDocument document, int pageNumber, List<Rectangle2D> rectCollection, Options options) {
+
+        var pdPage = document.getPage(pageNumber - 1);
+        drawRectangle2DList(document, rectCollection, options, pdPage);
+    }
+
+
+    private static void drawRectangle2DList(PDDocument document, List<Rectangle2D> rectCollection, Options options, PDPage pdPage) throws IOException {
+
+        var contentStream = new PDPageContentStream(document, pdPage, PDPageContentStream.AppendMode.APPEND, true);
+
+        contentStream.setStrokingColor(options.getStrokeColor());
+        contentStream.setNonStrokingColor(options.getFillColor());
+        contentStream.setLineWidth(options.getStrokeWidth());
+
+        for (var r : rectCollection) {
+            contentStream.addRect((float) r.getMinX(), (float) r.getMinY(), (float) r.getWidth(), (float) r.getHeight());
+
+            if (options.isStroke() && options.isFill()) {
+                contentStream.fillAndStroke();
+            } else if (options.isStroke()) {
+                contentStream.stroke();
+            } else if (options.isFill()) {
+                contentStream.fill();
+            }
+        }
+        contentStream.close();
+    }
+
+
+    @SneakyThrows
+    public static void drawRectanglesAndLinesPerPage(String filename, List<List<Rectangle2D>> list, List<List<Rectangle2D>> rectanglesPerPage, String tmpFileName) {
+
+        ClassPathResource pdfResource = new ClassPathResource(filename);
+        try (PDDocument pdDocument = Loader.loadPDF(pdfResource.getFile()); var out = new FileOutputStream(tmpFileName)) {
+            for (int pageNumber = 1; pageNumber < pdDocument.getNumberOfPages() + 1; pageNumber++) {
+//                PdfVisualisationUtility.drawLine2DList(pdDocument,
+//                        pageNumber,
+//                        list.get(pageNumber - 1),
+//                        PdfVisualisationUtility.Options.builder().stroke(true).build());
+                PdfVisualisationUtility.drawRectangle2DList(pdDocument,
+                        pageNumber,
+                        rectanglesPerPage.get(pageNumber - 1),
+                        PdfVisualisationUtility.Options.builder().stroke(true).build());
+                PdfVisualisationUtility.drawRectangle2DList(pdDocument, pageNumber, list.get(pageNumber - 1), PdfVisualisationUtility.Options.builder().stroke(true).build());
+            }
+            pdDocument.save(out);
+        }
+    }
+
+
+    @SneakyThrows
+    public static void drawLinesPerPage(String filename, List<List<Ruling>> linesPerPage, String tmpFileName) {
+
+        ClassPathResource pdfResource = new ClassPathResource(filename);
+        try (PDDocument pdDocument = Loader.loadPDF(pdfResource.getFile()); var out = new FileOutputStream(tmpFileName)) {
+            for (int pageNumber = 1; pageNumber < pdDocument.getNumberOfPages() + 1; pageNumber++) {
+                PdfVisualisationUtility.drawLine2DList(pdDocument,
+                        pageNumber,
+                        linesPerPage.get(pageNumber - 1),
+                        PdfVisualisationUtility.Options.builder().strokeColor(Color.RED).stroke(true).build());
+            }
+            pdDocument.save(out);
+        }
+    }
+
+
+    @Builder
+    @AllArgsConstructor
+    @Getter
+    @FieldDefaults(makeFinal = true, level = AccessLevel.PRIVATE)
+    public static class Options {
+
+        boolean stroke;
+        @Builder.Default
+        Color strokeColor = Color.BLACK;
+        @Builder.Default
+        float strokeWidth = 1f;
+
+        boolean fill;
+        @Builder.Default
+        Color fillColor = Color.BLACK;
+
+    }
+
+
+    private static Options buildStandardOptionsForNodes(DocumentTree.Entry entry) {
+
+        return Options.builder().stroke(true).strokeColor(switch (entry.getType()) {
+            case DOCUMENT -> Color.LIGHT_GRAY;
+            case HEADER, FOOTER -> Color.GREEN;
+            case PARAGRAPH -> Color.BLUE;
+            case HEADLINE -> Color.RED;
+            case SECTION -> Color.BLACK;
+            case TABLE -> Color.ORANGE;
+            case TABLE_CELL -> Color.GRAY;
+            case IMAGE -> Color.MAGENTA;
+        }).build();
+    }
+
+
+    private static void drawBBoxAndLabelAndNumberOnPage(PDDocument document, DocumentTree.Entry entry, Options options) {
+
+        Map<Page, Rectangle2D> rectanglesPerPage = entry.getNode().getBBox();
+        for (Page page : rectanglesPerPage.keySet()) {
+            Rectangle2D rectangle2D = rectanglesPerPage.get(page);
+            if (entry.getType() == NodeType.SECTION) {
+                rectangle2D = RectangleTransformations.pad(rectangle2D, 10, 10);
+            }
+            drawRectangle2DList(document, page.getNumber(), List.of(rectangle2D), options);
+            drawText(buildString(entry),
+                    document,
+                    new Point2D.Double(rectangle2D.getMinX(), rectangle2D.getMaxY() + 2),
+                    page.getNumber(),
+                    options,
+                    entry.getType() == NodeType.TABLE_CELL);
+        }
+    }
+
+
+    private static String buildString(DocumentTree.Entry entry) {
+
+        return entry.getNode().getNumberOnPage() + ": " + entry.getTreeId() + ": " + entry.getType();
+    }
+
+}

layoutparser-service/layoutparser-service-server/src/test/java/com/knecon/fforesight/service/layoutparser/server/LayoutparserEnd2EndTest.java

@@ -25,7 +25,9 @@ public class LayoutparserEnd2EndTest extends AbstractTest {
     @SneakyThrows
     public void testLayoutParserEndToEnd() {
 
-        prepareStorage("files/bdr/Wie weiter bei Kristeneinrichtungen.pdf");
+        String s = "（";
+        String s1 = "）";
+        prepareStorage("files/Minimal Examples/WrongOrderPage1.pdf");
         LayoutParsingRequest layoutParsingRequest = buildDefaultLayoutParsingRequest(LayoutParsingType.REDACT_MANAGER);
         LayoutParsingFinishedEvent finishedEvent = layoutParsingPipeline.parseLayoutAndSaveFilesToStorage(layoutParsingRequest);
         Arrays.stream(finishedEvent.message().split("\n")).forEach(log::info);

layoutparser-service/layoutparser-service-server/src/test/java/com/knecon/fforesight/service/layoutparser/server/graph/ViewerDocumentTest.java

@@ -25,7 +25,7 @@ public class ViewerDocumentTest extends BuildDocumentTest {
     @SneakyThrows
     public void testViewerDocument() {
 
-        String fileName = "files/S-Metolachlor_RAR_01_Volume_1_2018-09-06.pdf";
+        String fileName = "files/Plenarprotokoll 1 (keine Druchsache!) (1).pdf";
         String tmpFileName = "/tmp/" + Path.of(fileName).getFileName() + "_VIEWER.pdf";
 
         var documentFile = new ClassPathResource(fileName).getFile();
@@ -35,9 +35,10 @@ public class ViewerDocumentTest extends BuildDocumentTest {
         Document document = buildGraph(fileName, LayoutParsingType.REDACT_MANAGER);
         long start = System.currentTimeMillis();
         layoutGridService.addLayoutGrid(documentFile, document, new File(tmpFileName), true);
-        System.out.printf("Total time: %.2fs%n",  ((float) (System.currentTimeMillis() - start)) / 1000);
+        System.out.printf("Total time: %.2fs%n", ((float) (System.currentTimeMillis() - start)) / 1000);
     }
 
+
     @Test
     @Disabled
     @SneakyThrows
@@ -51,7 +52,11 @@ public class ViewerDocumentTest extends BuildDocumentTest {
         var tableResponse = mapper.readValue(new ClassPathResource(tableFileName).getInputStream(), TableServiceResponse.class);
         var documentFile = new ClassPathResource(fileName).getFile();
 
-        var classificationDocument = layoutParsingPipeline.parseLayout(LayoutParsingType.DOCUMINE, documentFile, new ImageServiceResponse(), tableResponse, Path.of(fileName).getFileName().toFile().toString());
+        var classificationDocument = layoutParsingPipeline.parseLayout(LayoutParsingType.DOCUMINE,
+                documentFile,
+                new ImageServiceResponse(),
+                tableResponse,
+                Path.of(fileName).getFileName().toFile().toString());
         ViewerDocumentService viewerDocumentService = new ViewerDocumentService(null);
         LayoutGridService layoutGridService = new LayoutGridService(viewerDocumentService);
         Document document = DocumentGraphFactory.buildDocumentGraph(classificationDocument);

layoutparser-service/layoutparser-service-server/src/test/java/com/knecon/fforesight/service/layoutparser/server/services/GapAcrossLinesDetectionServiceTest.java

@@ -48,7 +48,7 @@ class GapAcrossLinesDetectionServiceTest {
 
 
     @Test
-    @Disabled
+    //@Disabled
     @SneakyThrows
     public void testColumnDetection() {