Make margins collapse handling on cells a bit more consitent

DEVSIX-1195

Autoported commit.
Original commit hash: [0979cc53a]

Author: yulian-gaponenko

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

@@ -225,9 +225,7 @@ public virtual void EndMarginsCollapse(Rectangle layoutBox) {
             else {
                 ownCollapseAfter = new MarginsCollapse();
             }
-            if (ownCollapseAfter != null) {
-                ownCollapseAfter.JoinMargin(GetModelBottomMargin(renderer));
-            }
+            ownCollapseAfter.JoinMargin(GetModelBottomMargin(renderer));
             collapseInfo.SetOwnCollapseAfter(ownCollapseAfter);
             if (collapseInfo.IsSelfCollapsing()) {
                 if (prevChildMarginInfo != null) {
@@ -270,8 +268,7 @@ public virtual void EndMarginsCollapse(Rectangle layoutBox) {
         }
 
         private void UpdateCollapseBeforeIfPrevKidIsFirstAndSelfCollapsed(MarginsCollapse collapseAfter) {
-            if (prevChildMarginInfo.IsSelfCollapsing() && prevChildMarginInfo.IsIgnoreOwnMarginTop() && collapseAfter 
-                != null) {
+            if (prevChildMarginInfo.IsSelfCollapsing() && prevChildMarginInfo.IsIgnoreOwnMarginTop()) {
                 // prevChildMarginInfo.isIgnoreOwnMarginTop() is true only if it's the first kid and is adjoined to parent margin
                 collapseInfo.GetCollapseBefore().JoinMargin(collapseAfter);
             }
@@ -534,7 +531,8 @@ private static bool RendererIsFloated(IRenderer renderer) {
 
         private static float GetModelTopMargin(IRenderer renderer) {
             float? margin = renderer.GetModelElement().GetProperty<float?>(Property.MARGIN_TOP);
-            return margin != null ? (float)margin : 0;
+            // TODO Concerning "renderer instanceof CellRenderer" check: may be try to apply more general solution in future
+            return margin != null && !(renderer is CellRenderer) ? (float)margin : 0;
         }
 
         private static void IgnoreModelTopMargin(IRenderer renderer) {
@@ -547,7 +545,8 @@ private static void OverrideModelTopMargin(IRenderer renderer, float collapsedMa
 
         private static float GetModelBottomMargin(IRenderer renderer) {
             float? margin = renderer.GetModelElement().GetProperty<float?>(Property.MARGIN_BOTTOM);
-            return margin != null ? (float)margin : 0;
+            // TODO Concerning "renderer instanceof CellRenderer" check: may be try to apply more general solution in future
+            return margin != null && !(renderer is CellRenderer) ? (float)margin : 0;
         }
 
         private static void IgnoreModelBottomMargin(IRenderer renderer) {

itext/itext.layout/itext/layout/renderer/BlockRenderer.cs

@@ -96,9 +96,7 @@ public override LayoutResult Layout(LayoutContext layoutContext) {
             }
             bool isCellRenderer = this is CellRenderer;
             if (marginsCollapsingEnabled) {
-                if (!isCellRenderer) {
-                    marginsCollapseHandler.StartMarginsCollapse(parentBBox);
-                }
+                marginsCollapseHandler.StartMarginsCollapse(parentBBox);
             }
             Border[] borders = GetBorders();
             float[] paddings = GetPaddings();
@@ -141,9 +139,7 @@ public override LayoutResult Layout(LayoutContext layoutContext) {
                         if (result.GetStatus() != LayoutResult.NOTHING) {
                             marginsCollapseHandler.EndChildMarginsHandling(layoutBox);
                         }
-                        if (!isCellRenderer) {
-                            marginsCollapseHandler.EndMarginsCollapse(layoutBox);
-                        }
+                        marginsCollapseHandler.EndMarginsCollapse(layoutBox);
                     }
                     if (true.Equals(GetPropertyAsBoolean(Property.FILL_AVAILABLE_AREA_ON_SPLIT)) || true.Equals(GetPropertyAsBoolean
                         (Property.FILL_AVAILABLE_AREA))) {
@@ -338,7 +334,7 @@ public override LayoutResult Layout(LayoutContext layoutContext) {
                 }
             }
             float overflowPartHeight = GetOverflowPartHeight(overflowY, layoutBox);
-            if (marginsCollapsingEnabled && !isCellRenderer) {
+            if (marginsCollapsingEnabled) {
                 marginsCollapseHandler.EndMarginsCollapse(layoutBox);
             }
             if (true.Equals(GetPropertyAsBoolean(Property.FILL_AVAILABLE_AREA))) {

port-hash

@@ -1 +1 @@
-010d71ac111f8f411aa0a603cc5b8ecd5970ae79
+0979cc53a791b61b0108af67dd2fd747decb65f7