Utilize new LayoutTaggingHelper logic in layout classes

DEVSIX-1652

Author: yulian-gaponenko

layout/src/main/java/com/itextpdf/layout/Canvas.java

@@ -56,7 +56,7 @@ This file is part of the iText (R) project.
 /**
  * This class is used for adding content directly onto a specified {@link PdfCanvas}.
  * {@link Canvas} does not know the concept of a page, so it can't reflow to a 'next' {@link Canvas}.
- * 
+ *
  * This class effectively acts as a bridge between the high-level <em>layout</em>
  * API and the low-level <em>kernel</em> API.
  */
@@ -73,7 +73,7 @@ public class Canvas extends RootElement<Canvas> {
 
     /**
      * Creates a new Canvas to manipulate a specific document and page.
-     * 
+     *
      * @param pdfCanvas the low-level content stream writer
      * @param pdfDocument the document that the resulting content stream will be written to
      * @param rootArea the maximum area that the Canvas may write upon
@@ -100,7 +100,7 @@ public Canvas(PdfCanvas pdfCanvas, PdfDocument pdfDocument, Rectangle rootArea,
 
     /**
      * Creates a new Canvas to manipulate a specific {@link PdfFormXObject}.
-     * 
+     *
      * @param formXObject the form
      * @param pdfDocument the document that the resulting content stream will be written to
      */
@@ -134,7 +134,7 @@ public PdfCanvas getPdfCanvas() {
 
     /**
      * Sets the {@link IRenderer} for this Canvas.
-     * 
+     *
      * @param canvasRenderer a renderer specific for canvas operations
      */
     public void setRenderer(CanvasRenderer canvasRenderer) {
@@ -168,7 +168,7 @@ public boolean isAutoTaggingEnabled() {
      * Performs an entire recalculation of the element flow on the canvas,
      * taking into account all its current child elements. May become very
      * resource-intensive for large documents.
-     * 
+     *
      * Do not use when you have set {@link #immediateFlush} to <code>true</code>.
      */
     public void relayout() {
@@ -182,7 +182,7 @@ public void relayout() {
         }
         rootRenderer = (RootRenderer) nextRelayoutRenderer;
         for (IElement element : childElements) {
-            rootRenderer.addChild(element.createRendererSubTree());
+            createAndAddRendererSubTree(element);
         }
     }
 

layout/src/main/java/com/itextpdf/layout/Document.java

@@ -198,7 +198,7 @@ public void relayout() {
 
         rootRenderer = (RootRenderer) nextRelayoutRenderer;
         for (IElement element : childElements) {
-            rootRenderer.addChild(element.createRendererSubTree());
+            createAndAddRendererSubTree(element);
         }
     }
 

layout/src/main/java/com/itextpdf/layout/RootElement.java

@@ -64,15 +64,15 @@ This file is part of the iText (R) project.
 import com.itextpdf.layout.property.VerticalAlignment;
 import com.itextpdf.layout.renderer.IRenderer;
 import com.itextpdf.layout.renderer.RootRenderer;
+import com.itextpdf.layout.tagging.LayoutTaggingHelper;
 import com.itextpdf.layout.splitting.DefaultSplitCharacters;
 import com.itextpdf.layout.splitting.ISplitCharacters;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.Collections;
 import java.util.List;
-import java.util.Map;
 
 /**
  * A generic abstract root element for a PDF layout object hierarchy.
@@ -92,6 +92,8 @@ public abstract class RootElement<T extends IPropertyContainer> extends ElementP
 
     protected RootRenderer rootRenderer;
 
+    private LayoutTaggingHelper defaultLayoutTaggingHelper;
+
     /**
      * Adds an element to the root. The element is immediately placed in the contents.
      *
@@ -101,7 +103,7 @@ public abstract class RootElement<T extends IPropertyContainer> extends ElementP
      */
     public T add(IBlockElement element) {
         childElements.add(element);
-        ensureRootRendererNotNull().addChild(element.createRendererSubTree());
+        createAndAddRendererSubTree(element);
         if (immediateFlush) {
             childElements.remove(childElements.size() - 1);
         }
@@ -117,7 +119,7 @@ public T add(IBlockElement element) {
      */
     public T add(Image image) {
         childElements.add(image);
-        ensureRootRendererNotNull().addChild(image.createRendererSubTree());
+        createAndAddRendererSubTree(image);
         if (immediateFlush) {
             childElements.remove(childElements.size() - 1);
         }
@@ -188,6 +190,8 @@ public <T1> T1 getDefaultProperty(int property) {
                     return (T1) (Object) defaultSplitCharacters;
                 case Property.FONT_SIZE:
                     return (T1) (Object) UnitValue.createPointValue(12);
+                case Property.TAGGING_HELPER:
+                    return (T1) (Object) initTaggingHelperIfNeeded();
                 case Property.TEXT_RENDERING_MODE:
                     return (T1) (Object) PdfCanvasConstants.TextRenderingMode.FILL;
                 case Property.TEXT_RISE:
@@ -363,4 +367,17 @@ public T showTextAligned(Paragraph p, float x, float y, int pageNumber, TextAlig
     }
 
     protected abstract RootRenderer ensureRootRendererNotNull();
+
+    protected void createAndAddRendererSubTree(IElement element) {
+        IRenderer rendererSubTreeRoot = element.createRendererSubTree();
+        LayoutTaggingHelper taggingHelper = initTaggingHelperIfNeeded();
+        if (taggingHelper != null) {
+            taggingHelper.addKidsHint(pdfDocument.getTagStructureContext().getAutoTaggingPointer(), Collections.<IRenderer>singletonList(rendererSubTreeRoot));
+        }
+        ensureRootRendererNotNull().addChild(rendererSubTreeRoot);
+    }
+
+    private LayoutTaggingHelper initTaggingHelperIfNeeded() {
+        return defaultLayoutTaggingHelper == null && pdfDocument.isTagged() ? defaultLayoutTaggingHelper = new LayoutTaggingHelper(pdfDocument, immediateFlush) : defaultLayoutTaggingHelper;
+    }
 }

layout/src/main/java/com/itextpdf/layout/element/AbstractElement.java

@@ -43,14 +43,11 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.layout.element;
 
-import com.itextpdf.kernel.pdf.PdfName;
 import com.itextpdf.kernel.pdf.action.PdfAction;
-import com.itextpdf.kernel.pdf.tagutils.IAccessibleElement;
 import com.itextpdf.layout.ElementPropertyContainer;
 import com.itextpdf.layout.Style;
 import com.itextpdf.layout.property.Property;
 import com.itextpdf.layout.renderer.IRenderer;
-
 import java.util.ArrayList;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -59,7 +56,7 @@ This file is part of the iText (R) project.
 /**
  * Defines the most common properties that most {@link IElement} implementations
  * share.
- * 
+ *
  * @param <T> the type of the implementation
  */
 public abstract class AbstractElement<T extends IElement> extends ElementPropertyContainer<T> implements IElement {
@@ -123,6 +120,7 @@ public <T1> T1 getProperty(int property) {
     /**
      * Add a new style to this element. A style can be used as an effective way
      * to define multiple equal properties to several elements.
+     *
      * @param style the style to be added
      * @return this element
      */
@@ -131,30 +129,18 @@ public T addStyle(Style style) {
             styles = new LinkedHashSet<>();
         }
         styles.add(style);
-        return (T) (Object)this;
+        return (T) (Object) this;
     }
 
     /**
      * Gets the child elements of this elements
+     *
      * @return a list of children
      */
     public List<IElement> getChildren() {
         return childElements;
     }
 
-    protected abstract IRenderer makeNewRenderer();
-
-    /**
-     * Marks all child elements as artifacts recursively.
-     */
-    protected void propagateArtifactRoleToChildElements() {
-        for (IElement child : childElements) {
-            if (child instanceof IAccessibleElement) {
-                ((IAccessibleElement) child).setRole(PdfName.Artifact);
-            }
-        }
-    }
-
     /**
      * Returns <code>true</code> if this list contains no elements.
      *
@@ -168,7 +154,7 @@ public boolean isEmpty() {
      * Sets an action on this Element. An action is a general PDF concept that
      * signifies anything that makes the document interactive, e.g. a hyperlink
      * or a button.
-     * 
+     *
      * @param action the {@link PdfAction} that should be performed
      * @return this Element
      */
@@ -181,14 +167,16 @@ public T setAction(PdfAction action) {
      * Explicitly sets the page number this element should be put on. The location
      * on the page will be the same as if it were added at the end of the document,
      * but it will be located on the specified page.
-     * 
+     * <p>
      * This method should be used very carefully in client code.
-     * 
+     *
      * @param pageNumber the page number of the page this element should be placed on
      * @return this Element
      */
     public T setPageNumber(int pageNumber) {
         setProperty(Property.PAGE_NUMBER, pageNumber);
         return (T) (Object) this;
     }
+
+    protected abstract IRenderer makeNewRenderer();
 }

layout/src/main/java/com/itextpdf/layout/element/Cell.java

@@ -223,9 +223,6 @@ public PdfName getRole() {
     @Override
     public void setRole(PdfName role) {
         this.role = role;
-        if (PdfName.Artifact.equals(role)) {
-            propagateArtifactRoleToChildElements();
-        }
     }
 
     @Override

layout/src/main/java/com/itextpdf/layout/element/Div.java

@@ -53,7 +53,7 @@ This file is part of the iText (R) project.
  * A {@link Div} is a container object that defines a section in a document,
  * which will have some shared layout properties. Like all {@link BlockElement}
  * types, it will try to take up as much horizontal space as possible.
- * 
+ *
  * The concept is very similar to that of the div tag in HTML.
  */
 public class Div extends BlockElement<Div> {
@@ -63,18 +63,18 @@ public class Div extends BlockElement<Div> {
 
     /**
      * Adds any block element to the div's contents.
-     * 
+     *
      * @param element a {@link BlockElement}
      * @return this Element
      */
     public Div add(IBlockElement element) {
         childElements.add(element);
         return this;
     }
-    
+
     /**
      * Adds an image to the div's contents.
-     * 
+     *
      * @param element an {@link Image}
      * @return this Element
      */
@@ -102,9 +102,6 @@ public PdfName getRole() {
     @Override
     public void setRole(PdfName role) {
         this.role = role;
-        if (PdfName.Artifact.equals(role)) {
-            propagateArtifactRoleToChildElements();
-        }
     }
 
     @Override

layout/src/main/java/com/itextpdf/layout/element/List.java

@@ -194,7 +194,7 @@ public List setListSymbolAlignment(ListSymbolAlignment alignment) {
 
     /**
      * Gets the indent offset of the {@link ListItem} symbols.
-     * 
+     *
      * @return the indent offset as a <code>float</code>.
      */
     public Float getSymbolIndent() {
@@ -203,7 +203,7 @@ public Float getSymbolIndent() {
 
     /**
      * Sets the indent offset of the {@link ListItem} symbols.
-     * 
+     *
      * @param symbolIndent the new indent offset.
      * @return this list.
      */
@@ -252,9 +252,6 @@ public PdfName getRole() {
     @Override
     public void setRole(PdfName role) {
         this.role = role;
-        if (PdfName.Artifact.equals(role)) {
-            propagateArtifactRoleToChildElements();
-        }
     }
 
     @Override

layout/src/main/java/com/itextpdf/layout/element/Paragraph.java

@@ -150,7 +150,7 @@ public Paragraph addTabStops(java.util.List<TabStop> tabStops) {
     /**
      * Removes a tabstop position from the Paragraph, if it is present in the
      * {@link Property#TAB_STOPS} property.
-     * 
+     *
      * @param tabStopPosition the {@link TabStop} position to be removed.
      * @return this Paragraph
      * @see TabStop
@@ -182,7 +182,7 @@ public <T1> T1 getDefaultProperty(int property) {
 
     /**
      * Sets the indent value for the first line of the {@link Paragraph}.
-     * 
+     *
      * @param indent the indent value that must be applied to the first line of
      * the Paragraph, as a <code>float</code>
      * @return this Paragraph
@@ -194,7 +194,7 @@ public Paragraph setFirstLineIndent(float indent) {
 
     /**
      * Sets the leading value, using the {@link Leading#FIXED} strategy.
-     * 
+     *
      * @param leading the new leading value
      * @return this Paragraph
      * @see Leading
@@ -206,7 +206,7 @@ public Paragraph setFixedLeading(float leading) {
 
     /**
      * Sets the leading value, using the {@link Leading#MULTIPLIED} strategy.
-     * 
+     *
      * @param leading the new leading value
      * @return this Paragraph
      * @see Leading
@@ -240,9 +240,6 @@ public PdfName getRole() {
     @Override
     public void setRole(PdfName role) {
         this.role = role;
-        if (PdfName.Artifact.equals(role)) {
-            propagateArtifactRoleToChildElements();
-        }
     }
 
     @Override

layout/src/main/java/com/itextpdf/layout/element/Table.java

@@ -802,9 +802,6 @@ public PdfName getRole() {
     @Override
     public void setRole(PdfName role) {
         this.role = role;
-        if (PdfName.Artifact.equals(role)) {
-            propagateArtifactRoleToChildElements();
-        }
     }
 
     public Table setExtendBottomRow(boolean isExtended) {