Finalize anntotation flattening API

DEVSIX-2440

Author: guustysebie

kernel/src/main/java/com/itextpdf/kernel/logs/KernelLogMessageConstant.java

@@ -87,6 +87,8 @@ public final class KernelLogMessageConstant {
                     + "fail";
     public static final String FLATTENING_IS_NOT_YET_SUPPORTED =
             "Flattening annotation type {0} is not yet supported, it will not be removed from the page";
+    public static final String FORMFIELD_ANNOTATION_WILL_NOT_BE_FLATTENED = "Form field annotation flattening is not "
+            + "supported. Use the PdfAcroForm#flattenFields() method instead.";
 
     private KernelLogMessageConstant() {
         //Private constructor will prevent the instantiation of this class directly

kernel/src/main/java/com/itextpdf/kernel/utils/PdfAnnotationFlattener.java

@@ -25,11 +25,13 @@ This file is part of the iText (R) project.
 import com.itextpdf.commons.utils.MessageFormatUtil;
 import com.itextpdf.kernel.exceptions.KernelExceptionMessageConstant;
 import com.itextpdf.kernel.exceptions.PdfException;
+import com.itextpdf.kernel.pdf.PdfDocument;
 import com.itextpdf.kernel.pdf.PdfPage;
 import com.itextpdf.kernel.pdf.annot.PdfAnnotation;
 import com.itextpdf.kernel.utils.annotationsflattening.IAnnotationFlattener;
 import com.itextpdf.kernel.utils.annotationsflattening.PdfAnnotationFlattenFactory;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -63,36 +65,56 @@ public PdfAnnotationFlattener() {
      * {@link IAnnotationFlattener}.
      *
      * @param annotationsToFlatten the annotations that should be flattened.
-     * @param page                 the page where the annotations are located.
+     *
+     * @return the list of annotations that were not flattened successfully
      */
-    public void flatten(List<PdfAnnotation> annotationsToFlatten, PdfPage page) {
-        if (page == null) {
-            throw new PdfException(
-                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "page"));
-        }
+    public List<PdfAnnotation> flatten(List<PdfAnnotation> annotationsToFlatten) {
         if (annotationsToFlatten == null) {
             throw new PdfException(
                     MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL,
                             "annotationsToFlatten"));
         }
+        final List<PdfAnnotation> unFlattenedAnnotations = new ArrayList<>();
         for (final PdfAnnotation pdfAnnotation : annotationsToFlatten) {
+            if (pdfAnnotation == null) {
+                continue;
+            }
+            PdfPage page = pdfAnnotation.getPage();
+            if (page == null) {
+                continue;
+            }
             final IAnnotationFlattener worker = pdfAnnotationFlattenFactory.getAnnotationFlattenWorker(
                     pdfAnnotation.getSubtype());
-            worker.flatten(pdfAnnotation, page);
+            final boolean flattenedSuccessfully = worker.flatten(pdfAnnotation, page);
+            if (!flattenedSuccessfully) {
+                unFlattenedAnnotations.add(pdfAnnotation);
+            }
+
         }
+        return unFlattenedAnnotations;
     }
 
     /**
-     * Flattens all annotations on the page according to the defined implementation of
+     * Flattens the annotations on the page according to the defined implementation of
      * {@link IAnnotationFlattener}.
      *
-     * @param page the page where the annotations are located.
+     * @param document the document that contains the annotations that should be flattened.
+     *
+     * @return the list of annotations that were not flattened successfully
      */
-    public void flatten(PdfPage page) {
-        if (page == null) {
+    public List<PdfAnnotation> flatten(PdfDocument document) {
+        if (document == null) {
             throw new PdfException(
-                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "page"));
+                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "document"));
+        }
+        final List<PdfAnnotation> annotations = new ArrayList<>();
+        // Process page by page to avoid loading a bunch of annotations into memory
+        final int documentNumberOfPages = document.getNumberOfPages();
+        for (int i = 1; i <= documentNumberOfPages; i++) {
+            final PdfPage page = document.getPage(i);
+            final List<PdfAnnotation> failedFlatteningAnnotations = flatten(page.getAnnotations());
+            annotations.addAll(failedFlatteningAnnotations);
         }
-        flatten(page.getAnnotations(), page);
+        return annotations;
     }
 }

kernel/src/main/java/com/itextpdf/kernel/utils/annotationsflattening/PdfAnnotationFlattenFactory.java

@@ -34,8 +34,8 @@ public class PdfAnnotationFlattenFactory {
     static {
         map = new HashMap<>();
         map.put(PdfName.Link, () -> new DefaultAnnotationFlattener());
-        map.put(PdfName.Popup, () -> new NotSupportedFlattener());
-        map.put(PdfName.Widget, () -> new NotSupportedFlattener());
+        map.put(PdfName.Popup, () -> new RemoveWithoutDrawingFlattener());
+        map.put(PdfName.Widget, () -> new WarnFormfieldFlattener());
         map.put(PdfName.Screen, () -> new DefaultAnnotationFlattener());
         map.put(PdfName._3D, () -> new DefaultAnnotationFlattener());
         map.put(PdfName.Highlight, () -> new HighLightTextMarkupAnnotationFlattener());

kernel/src/main/java/com/itextpdf/kernel/utils/annotationsflattening/RemoveWithoutDrawingFlattener.java

@@ -0,0 +1,40 @@
+package com.itextpdf.kernel.utils.annotationsflattening;
+
+import com.itextpdf.commons.utils.MessageFormatUtil;
+import com.itextpdf.kernel.exceptions.KernelExceptionMessageConstant;
+import com.itextpdf.kernel.exceptions.PdfException;
+import com.itextpdf.kernel.pdf.PdfPage;
+import com.itextpdf.kernel.pdf.annot.PdfAnnotation;
+
+/**
+ * This class is used to Remove annotations without drawing them on the page content stream.
+ */
+public class RemoveWithoutDrawingFlattener implements IAnnotationFlattener {
+
+
+    /**
+     * Creates a new {@link RemoveWithoutDrawingFlattener} instance.
+     */
+    public RemoveWithoutDrawingFlattener() {
+        //empty constructor
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean flatten(PdfAnnotation annotation, PdfPage page) {
+        if (annotation == null) {
+            throw new PdfException(
+                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "annotation"));
+        }
+        if (page == null) {
+            throw new PdfException(
+                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "page"));
+        }
+        page.removeAnnotation(annotation);
+        return true;
+    }
+}
+
+

kernel/src/main/java/com/itextpdf/kernel/utils/annotationsflattening/WarnFormfieldFlattener.java

@@ -0,0 +1,43 @@
+package com.itextpdf.kernel.utils.annotationsflattening;
+
+import com.itextpdf.commons.utils.MessageFormatUtil;
+import com.itextpdf.kernel.exceptions.KernelExceptionMessageConstant;
+import com.itextpdf.kernel.exceptions.PdfException;
+import com.itextpdf.kernel.logs.KernelLogMessageConstant;
+import com.itextpdf.kernel.pdf.PdfPage;
+import com.itextpdf.kernel.pdf.annot.PdfAnnotation;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class is used to warn user that annotation will not be flattened.
+ */
+public class WarnFormfieldFlattener implements IAnnotationFlattener {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(WarnFormfieldFlattener.class);
+
+    /**
+     * Creates a new {@link WarnFormfieldFlattener} instance.
+     */
+    public WarnFormfieldFlattener() {
+        //empty constructor
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean flatten(PdfAnnotation annotation, PdfPage page) {
+        if (annotation == null) {
+            throw new PdfException(
+                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "annotation"));
+        }
+        if (page == null) {
+            throw new PdfException(
+                    MessageFormatUtil.format(KernelExceptionMessageConstant.ARG_SHOULD_NOT_BE_NULL, "page"));
+        }
+        LOGGER.warn(KernelLogMessageConstant.FORMFIELD_ANNOTATION_WILL_NOT_BE_FLATTENED);
+        return false;
+    }
+}