Implement float elements splitting

DEVSIX-1267

Autoported commit.
Original commit hash: [90f44ffeb]

Author: pavel-morozov-duallab

itext.tests/itext.layout.tests/itext/layout/FloatTest.cs

@@ -202,6 +202,10 @@ public virtual void FloatDivTest02() {
         [NUnit.Framework.Test]
         [NUnit.Framework.Ignore("block level floating elements page-overflow and splitting not supported yet")]
         public virtual void FloatDivTest03() {
+            //
+            // TODO probably we shouldn't review forced placement applying on floated elements
+            // May be check if there are any floated elements already on page
+            //
             String cmpFileName = sourceFolder + "cmp_floatDivTest03.pdf";
             String outFile = destinationFolder + "floatDivTest03.pdf";
             PdfWriter writer = new PdfWriter(outFile);

itext.tests/itext.layout.tests/resources/itext/layout/FloatTest/cmp_floatFixedHeightContentNotFit.pdf

@@ -221,6 +221,9 @@ public virtual void EndMarginsCollapse(Rectangle layoutBox) {
                 () && !lastKidCollapsedAfterHasClearanceApplied;
             if (lastChildMarginJoinedToParent) {
                 ownCollapseAfter = prevChildMarginInfo.GetOwnCollapseAfter();
+                if (ownCollapseAfter == null) {
+                    ownCollapseAfter = new MarginsCollapse();
+                }
             }
             else {
                 ownCollapseAfter = new MarginsCollapse();

itext/itext.layout/itext/layout/margincollapse/MarginsCollapseHandler.cs

@@ -44,6 +44,7 @@ source product.
 using System;
 using System.Collections.Generic;
 using System.Text;
+using Java.Lang;
 using iText.IO.Log;
 using iText.IO.Util;
 using iText.Kernel.Colors;
@@ -335,6 +336,35 @@ public virtual TransparentColor GetPropertyAsTransparentColor(int property) {
             return this.GetProperty<TransparentColor>(property);
         }
 
+        /// <summary>Returns a property with a certain key, as a floating point value.</summary>
+        /// <param name="property">
+        /// an
+        /// <see cref="iText.Layout.Properties.Property">enum value</see>
+        /// </param>
+        /// <returns>
+        /// a
+        /// <see cref="float?"/>
+        /// </returns>
+        public virtual float? GetPropertyAsFloat(int property) {
+            Number value = this.GetProperty<Number>(property);
+            return value != null ? value : null;
+        }
+
+        /// <summary>Returns a property with a certain key, as a floating point value.</summary>
+        /// <param name="property">
+        /// an
+        /// <see cref="iText.Layout.Properties.Property">enum value</see>
+        /// </param>
+        /// <param name="defaultValue">default value to be returned if property is not found</param>
+        /// <returns>
+        /// a
+        /// <see cref="float?"/>
+        /// </returns>
+        public virtual float? GetPropertyAsFloat(int property, float? defaultValue) {
+            Number value = this.GetProperty<Number>(property, defaultValue);
+            return value != null ? value : null;
+        }
+
         /// <summary>Returns a property with a certain key, as a boolean value.</summary>
         /// <param name="property">
         /// an
@@ -348,6 +378,20 @@ public virtual TransparentColor GetPropertyAsTransparentColor(int property) {
             return this.GetProperty<bool?>(property);
         }
 
+        /// <summary>Returns a property with a certain key, as an integer value.</summary>
+        /// <param name="property">
+        /// an
+        /// <see cref="iText.Layout.Properties.Property">enum value</see>
+        /// </param>
+        /// <returns>
+        /// a
+        /// <see cref="int?"/>
+        /// </returns>
+        public virtual int? GetPropertyAsInteger(int property) {
+            Number value = GetProperty(property);
+            return value != null ? value : null;
+        }
+
         /// <summary>Returns a string representation of the renderer.</summary>
         /// <returns>
         /// a
@@ -476,25 +520,18 @@ public virtual void DrawBackground(DrawContext drawContext) {
         /// </summary>
         /// <param name="drawContext">the context (canvas, document, etc) of this drawing operation.</param>
         public virtual void DrawChildren(DrawContext drawContext) {
-            IList<IRenderer> waitingRenderers = new List<IRenderer>();
             foreach (IRenderer child in childRenderers) {
                 if (FloatingHelper.IsRendererFloating(child)) {
                     RootRenderer rootRenderer = GetRootRenderer();
                     if (rootRenderer != null) {
                         rootRenderer.waitingDrawingElements.Add(child);
                         child.SetProperty(Property.FLOAT, null);
                     }
-                    else {
-                        waitingRenderers.Add(child);
-                    }
                 }
                 else {
                     child.Draw(drawContext);
                 }
             }
-            foreach (IRenderer waitingRenderer in waitingRenderers) {
-                waitingRenderer.Draw(drawContext);
-            }
         }
 
         /// <summary>
@@ -1211,9 +1248,9 @@ protected internal virtual float[] CalculateShiftToPositionBBoxOfPointsAt(float
         }
 
         protected internal virtual void OverrideHeightProperties() {
-            float? height = this.GetPropertyAsFloat(Property.HEIGHT);
-            float? maxHeight = this.GetPropertyAsFloat(Property.MAX_HEIGHT);
-            float? minHeight = this.GetPropertyAsFloat(Property.MIN_HEIGHT);
+            float? height = this.GetPropertyAsFloat<float>(Property.HEIGHT);
+            float? maxHeight = this.GetPropertyAsFloat<float>(Property.MAX_HEIGHT);
+            float? minHeight = this.GetPropertyAsFloat<float>(Property.MIN_HEIGHT);
             if (null != height) {
                 if (null == maxHeight || height < maxHeight) {
                     maxHeight = height;