RED-6019: Remove hidden text when processing OCR
*moved InvisibleElementRemovalDto to private inner record of InvisibleElementRemovalService *added comments for color choices
This commit is contained in:
Kilian Schuettler
parent
12fbdbee50
commit
a96260f77f
@ -1,25 +0,0 @@
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package com.iqser.red.service.ocr.v1.server.model;
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import java.util.List;
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import java.util.Set;
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import com.pdftron.pdf.ElementReader;
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import lombok.AccessLevel;
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import lombok.Builder;
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import lombok.Data;
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import lombok.experimental.FieldDefaults;
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@Data
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@Builder
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@FieldDefaults(level = AccessLevel.PRIVATE, makeFinal = true)
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public class InvisibleElementRemovalDto {
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boolean delta;
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ElementReader reader;
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ClippingPathStack clippingPathStack;
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List<ElementFeatures> overlappedElements;
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List<ElementFeatures> visibleElements;
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Set<Long> visitedXObjIds;
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}
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@ -17,7 +17,6 @@ import com.google.common.primitives.Bytes;
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import com.google.common.primitives.Doubles;
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import com.iqser.red.service.ocr.v1.server.model.ClippingPathStack;
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import com.iqser.red.service.ocr.v1.server.model.ElementFeatures;
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import com.iqser.red.service.ocr.v1.server.model.InvisibleElementRemovalDto;
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import com.pdftron.common.Matrix2D;
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import com.pdftron.common.PDFNetException;
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import com.pdftron.pdf.ColorPt;
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@ -35,6 +34,7 @@ import com.pdftron.pdf.Rect;
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import com.pdftron.sdf.Obj;
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import com.pdftron.sdf.SDFDoc;
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import lombok.Builder;
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import lombok.SneakyThrows;
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import lombok.extern.slf4j.Slf4j;
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@ -75,7 +75,7 @@ public class InvisibleElementRemovalService {
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Page page = iterator.next();
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visitedXObjIds.add(page.getSDFObj().getObjNum());
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InvisibleElementRemovalDto dto = InvisibleElementRemovalDto.builder()
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InvisibleElementRemovalContext context = InvisibleElementRemovalContext.builder()
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.reader(reader)
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.clippingPathStack(new ClippingPathStack(page.getMediaBox()))
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.delta(delta)
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@ -84,40 +84,42 @@ public class InvisibleElementRemovalService {
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.visitedXObjIds(visitedXObjIds)
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.build();
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removeClippedElementsAndInvisibleTextAndRememberOverlappedElements(page, writer, dto);
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removeClippedElementsAndInvisibleTextAndRememberOverlappedElements(page, writer, context);
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dto.getVisitedXObjIds().clear();
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context.visitedXObjIds().clear();
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removeOverlappedElements(page, writer, dto);
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removeOverlappedElements(page, writer, context);
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}
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return pdfDoc.save(SDFDoc.SaveMode.REMOVE_UNUSED, null);
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}
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private void removeClippedElementsAndInvisibleTextAndRememberOverlappedElements(Page page, ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void removeClippedElementsAndInvisibleTextAndRememberOverlappedElements(Page page,
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ElementWriter writer,
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InvisibleElementRemovalContext context) throws PDFNetException {
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dto.getReader().begin(page);
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context.reader().begin(page);
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writer.begin(page, ElementWriter.e_replacement, false, true, page.getResourceDict());
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processElements(writer, dto);
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processElements(writer, context);
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writer.end();
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dto.getReader().end();
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context.reader().end();
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}
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private void processElements(ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processElements(ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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for (Element element = dto.getReader().next(); element != null; element = dto.getReader().next())
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for (Element element = context.reader().next(); element != null; element = context.reader().next())
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switch (element.getType()) {
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case Element.e_image, Element.e_inline_image -> processImages(element, writer, dto);
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case Element.e_text -> processText(element, writer, dto);
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case Element.e_path -> processPath(element, writer, dto);
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case Element.e_form -> processForm(element, writer, dto);
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case Element.e_image, Element.e_inline_image -> processImages(element, writer, context);
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case Element.e_text -> processText(element, writer, context);
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case Element.e_path -> processPath(element, writer, context);
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case Element.e_form -> processForm(element, writer, context);
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case Element.e_group_begin -> {
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dto.getClippingPathStack().enterNewGState();
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context.clippingPathStack().enterNewGState();
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writer.writeElement(element);
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}
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case Element.e_group_end -> {
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dto.getClippingPathStack().leaveGState();
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context.clippingPathStack().leaveGState();
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writer.writeElement(element);
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}
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default -> writer.writeElement(element);
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@ -125,7 +127,7 @@ public class InvisibleElementRemovalService {
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}
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private void processImages(Element imageElement, ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processImages(Element imageElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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Rect rect = imageElement.getBBox();
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@ -133,19 +135,19 @@ public class InvisibleElementRemovalService {
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return;
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}
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boolean inClippingPath = dto.getClippingPathStack().almostIntersects(rect.getX1(), rect.getY1(), rect.getWidth(), rect.getHeight());
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boolean inClippingPath = context.clippingPathStack().almostIntersects(rect.getX1(), rect.getY1(), rect.getWidth(), rect.getHeight());
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if (!dto.isDelta() && inClippingPath) {
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dto.getVisibleElements().add(ElementFeatures.extractFeatures(imageElement));
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if (!context.delta() && inClippingPath) {
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context.visibleElements().add(ElementFeatures.extractFeatures(imageElement));
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}
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if (dto.isDelta() ^ inClippingPath) {
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if (context.delta() ^ inClippingPath) {
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writer.writeElement(imageElement);
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}
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}
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private void processText(Element textElement, ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processText(Element textElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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Rect rect = textElement.getBBox();
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@ -156,14 +158,14 @@ public class InvisibleElementRemovalService {
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GState gState = textElement.getGState();
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boolean inClippingPath = dto.getClippingPathStack().almostIntersects(rect.getX1(), rect.getY1(), rect.getWidth(), rect.getHeight());
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boolean inClippingPath = context.clippingPathStack().almostIntersects(rect.getX1(), rect.getY1(), rect.getWidth(), rect.getHeight());
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boolean isTextVisible = isTextRenderedVisibly(gState);
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if (inClippingPath && isTextVisible) {
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dto.getVisibleElements().add(ElementFeatures.extractFeatures(textElement));
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context.visibleElements().add(ElementFeatures.extractFeatures(textElement));
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}
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if (!dto.isDelta()) {
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if (!context.delta()) {
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if (inClippingPath && isTextVisible) {
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writer.writeElement(textElement);
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} else if (textElement.hasTextMatrix()) {
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@ -178,11 +180,13 @@ public class InvisibleElementRemovalService {
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} else {
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if (!inClippingPath) {
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gState.setFillColorSpace(ColorSpace.createDeviceRGB());
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// red for elements removed by clipping path
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gState.setFillColor(new ColorPt(1, 0, 0));
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writer.writeElement(textElement);
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}
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if (!isTextVisible) {
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gState.setFillColorSpace(ColorSpace.createDeviceRGB());
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// blue for elements removed due to transparency or not rendered
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gState.setFillColor(new ColorPt(0, 0, 1));
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gState.setTextRenderMode(GState.e_fill_text);
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gState.setFillOpacity(1);
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@ -192,30 +196,30 @@ public class InvisibleElementRemovalService {
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}
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private void processForm(Element formElement, ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processForm(Element formElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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writer.writeElement(formElement);
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Obj formObj = formElement.getXObject();
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if (!dto.getVisitedXObjIds().contains(formObj.getObjNum())) {
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dto.getVisitedXObjIds().add(formObj.getObjNum());
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if (!context.visitedXObjIds().contains(formObj.getObjNum())) {
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context.visitedXObjIds().add(formObj.getObjNum());
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// writer needs to be newly initialized when entering a new content stream
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// see ElementEditTest in PDFTron (https://www.pdftron.com/documentation/samples/android/java/ElementEditTest)
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ElementWriter formWriter = new ElementWriter();
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dto.getReader().formBegin();
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context.reader().formBegin();
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formWriter.begin(formObj);
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dto.getReader().clearChangeList();
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formWriter.setDefaultGState(dto.getReader());
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context.reader().clearChangeList();
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formWriter.setDefaultGState(context.reader());
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processElements(formWriter, dto);
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processElements(formWriter, context);
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formWriter.end();
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dto.getReader().end();
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context.reader().end();
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}
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}
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private void processPath(Element pathElement, ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processPath(Element pathElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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GeneralPath linePath = convertToGeneralPath(pathElement.getPathData());
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@ -226,7 +230,7 @@ public class InvisibleElementRemovalService {
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var rect = linePath.getBounds2D();
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boolean inClippingPath = dto.getClippingPathStack().almostIntersects(rect.getX(), rect.getY(), rect.getWidth(), rect.getHeight());
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boolean inClippingPath = context.clippingPathStack().almostIntersects(rect.getX(), rect.getY(), rect.getWidth(), rect.getHeight());
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if (pathElement.isClippingPath()) {
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if (pathElement.isClipWindingFill()) {
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@ -235,27 +239,27 @@ public class InvisibleElementRemovalService {
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linePath.setWindingRule(GeneralPath.WIND_EVEN_ODD);
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}
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dto.getClippingPathStack().intersectClippingPath(linePath);
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pathElement.setPathClip(!dto.isDelta());
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context.clippingPathStack().intersectClippingPath(linePath);
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pathElement.setPathClip(!context.delta());
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writer.writeElement(pathElement);
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} else {
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if (inClippingPath) {
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// TODO: WINDING RULE
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if (isFilledAndNonTransparent(pathElement)) {
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List<ElementFeatures> currentOverlappedElements = dto.getVisibleElements()
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List<ElementFeatures> currentOverlappedElements = context.visibleElements()
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.stream()
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.filter(features -> almostContains(linePath, features.getBoundingBox()))
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.toList();
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dto.getOverlappedElements().addAll(currentOverlappedElements);
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dto.getVisibleElements().removeAll(currentOverlappedElements);
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context.overlappedElements().addAll(currentOverlappedElements);
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context.visibleElements().removeAll(currentOverlappedElements);
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}
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dto.getVisibleElements().add(ElementFeatures.extractFeatures(pathElement));
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if (!dto.isDelta()) {
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context.visibleElements().add(ElementFeatures.extractFeatures(pathElement));
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if (!context.delta()) {
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writer.writeElement(pathElement);
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}
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}
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if (dto.isDelta() && !inClippingPath) {
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if (context.delta() && !inClippingPath) {
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pathElement.getGState().setFillColorSpace(ColorSpace.createDeviceRGB());
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pathElement.getGState().setFillColor(new ColorPt(1, 0, 0));
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pathElement.getGState().setStrokeColorSpace(ColorSpace.createDeviceRGB());
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@ -272,34 +276,35 @@ public class InvisibleElementRemovalService {
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}
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private void removeOverlappedElements(Page page, ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void removeOverlappedElements(Page page, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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dto.getReader().begin(page);
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context.reader().begin(page);
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writer.begin(page, ElementWriter.e_replacement, false, true, page.getResourceDict());
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if (dto.isDelta()) {
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dto.getOverlappedElements().forEach(feature -> drawBBox(writer, feature.getBoundingBox(), "#00FF00"));
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dto.getOverlappedElements().clear();
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if (context.delta()) {
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// green for element removed due to overlapping
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context.overlappedElements().forEach(feature -> drawBBox(writer, feature.getBoundingBox(), "#00FF00"));
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context.overlappedElements().clear();
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}
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processOverlappedElements(writer, dto);
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processOverlappedElements(writer, context);
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writer.end();
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dto.getReader().end();
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context.reader().end();
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if (dto.getOverlappedElements().size() > 0) {
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log.warn(dto.getOverlappedElements().size() + " overlapped elements have not been found or removed");
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if (context.overlappedElements().size() > 0) {
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log.warn(context.overlappedElements().size() + " overlapped elements have not been found or removed");
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}
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}
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private void processOverlappedElements(ElementWriter writer, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processOverlappedElements(ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
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for (Element element = dto.getReader().next(); element != null; element = dto.getReader().next()) {
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for (Element element = context.reader().next(); element != null; element = context.reader().next()) {
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switch (element.getType()) {
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case Element.e_form -> processFormOverlappedElements(writer, element, dto);
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case Element.e_form -> processFormOverlappedElements(writer, element, context);
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case Element.e_path, Element.e_image, Element.e_inline_image, Element.e_text -> {
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boolean anyMatch = false;
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for (ElementFeatures elementToRemove : dto.getOverlappedElements()) {
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for (ElementFeatures elementToRemove : context.overlappedElements()) {
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if (elementToRemove.almostMatches(element)) {
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dto.getOverlappedElements().remove(elementToRemove);
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context.overlappedElements().remove(elementToRemove);
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anyMatch = true;
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break;
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}
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@ -322,25 +327,25 @@ public class InvisibleElementRemovalService {
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}
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private void processFormOverlappedElements(ElementWriter writer, Element formElement, InvisibleElementRemovalDto dto) throws PDFNetException {
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private void processFormOverlappedElements(ElementWriter writer, Element formElement, InvisibleElementRemovalContext context) throws PDFNetException {
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writer.writeElement(formElement);
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Obj formObj = formElement.getXObject();
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if (!dto.getVisitedXObjIds().contains(formObj.getObjNum())) {
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dto.getVisitedXObjIds().add(formObj.getObjNum());
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if (!context.visitedXObjIds().contains(formObj.getObjNum())) {
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context.visitedXObjIds().add(formObj.getObjNum());
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// writer needs to be newly initialized when entering a new content stream
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// see ElementEditTest in PDFTron (https://www.pdftron.com/documentation/samples/android/java/ElementEditTest)
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ElementWriter formWriter = new ElementWriter();
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dto.getReader().formBegin();
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context.reader().formBegin();
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formWriter.begin(formObj);
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dto.getReader().clearChangeList();
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formWriter.setDefaultGState(dto.getReader());
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context.reader().clearChangeList();
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formWriter.setDefaultGState(context.reader());
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processOverlappedElements(formWriter, dto);
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processOverlappedElements(formWriter, context);
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formWriter.end();
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dto.getReader().end();
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context.reader().end();
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}
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}
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@ -416,4 +421,15 @@ public class InvisibleElementRemovalService {
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writer.writePlacedElement(rect);
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}
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@Builder
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private record InvisibleElementRemovalContext(boolean delta, //
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ElementReader reader, //
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ClippingPathStack clippingPathStack, //
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List<ElementFeatures> overlappedElements, //
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List<ElementFeatures> visibleElements, //
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Set<Long> visitedXObjIds) {
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}
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}
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