Prepare TargetCounterHandler to used from pure layout code

DEVSIX-5502

Autoported commit.
Original commit hash: [e1a238052]

Author: Snipx

itext.tests/itext.layout.tests/itext/layout/renderer/TargetCounterHandlerTest.cs

@@ -25,6 +25,9 @@ You should have received a copy of the GNU Affero General Public License
 using iText.IO.Image;
 using iText.Kernel.Font;
 using iText.Kernel.Geom;
+using iText.Kernel.Pdf;
+using iText.Kernel.Utils;
+using iText.Layout;
 using iText.Layout.Element;
 using iText.Layout.Layout;
 using iText.Layout.Properties;
@@ -33,6 +36,17 @@ You should have received a copy of the GNU Affero General Public License
 
 namespace iText.Layout.Renderer {
     public class TargetCounterHandlerTest : ExtendedITextTest {
+        public static readonly String SOURCE_FOLDER = iText.Test.TestUtil.GetParentProjectDirectory(NUnit.Framework.TestContext
+            .CurrentContext.TestDirectory) + "/resources/itext/layout/renderer/TargetCounterHandlerTest/";
+
+        public static readonly String DESTINATION_FOLDER = NUnit.Framework.TestContext.CurrentContext.TestDirectory
+             + "/test/itext/layout/renderer/TargetCounterHandlerTest/";
+
+        [NUnit.Framework.OneTimeSetUp]
+        public static void BeforeClass() {
+            CreateDestinationFolder(DESTINATION_FOLDER);
+        }
+
         [NUnit.Framework.Test]
         public virtual void BlockRendererAddByIDTest() {
             DocumentRenderer documentRenderer = new DocumentRenderer(null);
@@ -117,5 +131,62 @@ public virtual void LineRendererAddByIDTest() {
             documentRenderer.GetTargetCounterHandler().PrepareHandlerToRelayout();
             NUnit.Framework.Assert.AreEqual((int?)4, TargetCounterHandler.GetPageByID(lineRenderer, id));
         }
+
+        [NUnit.Framework.Test]
+        public virtual void TargetCounterHandlerEndToEndLayoutTest() {
+            String targetPdf = DESTINATION_FOLDER + "targetCounterHandlerEndToEndLayoutTest.pdf";
+            String cmpPdf = SOURCE_FOLDER + "cmp_targetCounterHandlerEndToEndLayoutTest.pdf";
+            Document document = new Document(new PdfDocument(new PdfWriter(targetPdf)), PageSize.A4, false);
+            Text pageNumPlaceholder = new Text("x");
+            String id = "1";
+            pageNumPlaceholder.SetProperty(Property.ID, id);
+            pageNumPlaceholder.SetNextRenderer(new TargetCounterHandlerTest.TargetCounterAwareTextRenderer(pageNumPlaceholder
+                ));
+            Paragraph intro = new Paragraph("The paragraph is on page ").Add(pageNumPlaceholder);
+            document.Add(intro);
+            document.Add(new AreaBreak());
+            Paragraph text = new Paragraph("This is main text");
+            text.SetProperty(Property.ID, id);
+            text.SetNextRenderer(new TargetCounterHandlerTest.TargetCounterAwareParagraphRenderer(text));
+            document.Add(text);
+            document.Relayout();
+            document.Close();
+            NUnit.Framework.Assert.IsNull(new CompareTool().CompareByContent(targetPdf, cmpPdf, DESTINATION_FOLDER, "diff"
+                ));
+        }
+
+        private class TargetCounterAwareTextRenderer : TextRenderer {
+            public TargetCounterAwareTextRenderer(Text link)
+                : base(link) {
+            }
+
+            public override LayoutResult Layout(LayoutContext layoutContext) {
+                int? targetPageNumber = TargetCounterHandler.GetPageByID(this, this.GetProperty<String>(Property.ID));
+                if (targetPageNumber != null) {
+                    SetText(targetPageNumber.ToString());
+                }
+                return base.Layout(layoutContext);
+            }
+
+            public override IRenderer GetNextRenderer() {
+                return new TargetCounterHandlerTest.TargetCounterAwareTextRenderer((Text)GetModelElement());
+            }
+        }
+
+        private class TargetCounterAwareParagraphRenderer : ParagraphRenderer {
+            public TargetCounterAwareParagraphRenderer(Paragraph modelElement)
+                : base(modelElement) {
+            }
+
+            public override IRenderer GetNextRenderer() {
+                return new TargetCounterHandlerTest.TargetCounterAwareParagraphRenderer((Paragraph)modelElement);
+            }
+
+            public override LayoutResult Layout(LayoutContext layoutContext) {
+                LayoutResult result = base.Layout(layoutContext);
+                TargetCounterHandler.AddPageByID(this);
+                return result;
+            }
+        }
     }
 }

itext.tests/itext.layout.tests/resources/itext/layout/renderer/TargetCounterHandlerTest/cmp_targetCounterHandlerEndToEndLayoutTest.pdf

@@ -220,6 +220,9 @@ public virtual void Relayout() {
             if (immediateFlush) {
                 throw new InvalidOperationException("Operation not supported with immediate flush");
             }
+            if (rootRenderer is DocumentRenderer) {
+                ((DocumentRenderer)rootRenderer).GetTargetCounterHandler().PrepareHandlerToRelayout();
+            }
             IRenderer nextRelayoutRenderer = rootRenderer != null ? rootRenderer.GetNextRenderer() : null;
             if (nextRelayoutRenderer == null || !(nextRelayoutRenderer is RootRenderer)) {
                 nextRelayoutRenderer = new DocumentRenderer(this, immediateFlush);

itext/itext.layout/itext/layout/Document.cs

@@ -98,7 +98,10 @@ public override LayoutArea GetOccupiedArea() {
         /// </summary>
         /// <returns>relayout renderer.</returns>
         public override IRenderer GetNextRenderer() {
-            return new iText.Layout.Renderer.DocumentRenderer(document, immediateFlush);
+            iText.Layout.Renderer.DocumentRenderer renderer = new iText.Layout.Renderer.DocumentRenderer(document, immediateFlush
+                );
+            renderer.targetCounterHandler = new TargetCounterHandler(targetCounterHandler);
+            return renderer;
         }
 
         protected internal override LayoutArea UpdateCurrentArea(LayoutResult overflowResult) {
@@ -171,7 +174,8 @@ protected internal virtual PageSize AddNewPage(PageSize customPageSize) {
         /// <summary>Adds some pages so that the overall number is at least n.</summary>
         /// <remarks>
         /// Adds some pages so that the overall number is at least n.
-        /// Returns the page size of the n'th page.
+        /// Returns the page size of the page number
+        /// <paramref name="n"/>.
         /// </remarks>
         private PageSize EnsureDocumentHasNPages(int n, PageSize customPageSize) {
             PageSize lastPageSize = null;
@@ -191,8 +195,8 @@ private Rectangle GetCurrentPageEffectiveArea(PageSize pageSize) {
         }
 
         private void MoveToNextPage() {
-            // We don't flush this page immediately, but only flush previous one because of manipulations with areas in case
-            // of keepTogether property.
+            // We don't flush this page immediately, but only flush previous one because of manipulations
+            // with areas in case of keepTogether property.
             if (immediateFlush && currentPageNumber > 1) {
                 document.GetPdfDocument().GetPage(currentPageNumber - 1).Flush();
             }

itext/itext.layout/itext/layout/renderer/DocumentRenderer.cs

@@ -1 +1 @@
-a009bcd1103b8b23197dc80b02686acbe3fc9c0e
+e1a23805224ab56798adce94240ba5958890c466