From 656d1a6ecffd4ec00be2cf099047b07fbcefb053 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcin=20Zi=C4=85bek?= <marcin.ziabek@uj.edu.pl>
Date: Thu, 16 Dec 2021 01:39:26 +0100
Subject: [PATCH] Improved Row element stability

---
 QuestPDF.Examples/Engine/RenderingTest.cs | 11 +++--
 QuestPDF.Examples/RowExamples.cs          | 56 +++++++++++++++++++++++
 QuestPDF/Elements/Row.cs                  | 24 ++++++++--
 QuestPDF/Infrastructure/Element.cs        |  5 --
 4 files changed, 82 insertions(+), 14 deletions(-)
 create mode 100644 QuestPDF.Examples/RowExamples.cs

diff --git a/QuestPDF.Examples/Engine/RenderingTest.cs b/QuestPDF.Examples/Engine/RenderingTest.cs
index 3309c4a..975af95 100644
--- a/QuestPDF.Examples/Engine/RenderingTest.cs
+++ b/QuestPDF.Examples/Engine/RenderingTest.cs
@@ -67,6 +67,12 @@ namespace QuestPDF.Examples.Engine
             return this;
         }
         
+        public RenderingTest MaxPages(int value)
+        {
+            MaxPagesThreshold = value;
+            return this;
+        }
+        
         public void Render(Action<IContainer> content)
         {
             RenderDocument(container =>
@@ -78,11 +84,6 @@ namespace QuestPDF.Examples.Engine
                 });
             });
         }
-        
-        public void MaxPages(int value)
-        {
-            MaxPagesThreshold = value;
-        }
 
         public void RenderDocument(Action<IDocumentContainer> content)
         {
diff --git a/QuestPDF.Examples/RowExamples.cs b/QuestPDF.Examples/RowExamples.cs
new file mode 100644
index 0000000..ffb6dfc
--- /dev/null
+++ b/QuestPDF.Examples/RowExamples.cs
@@ -0,0 +1,56 @@
+using NUnit.Framework;
+using QuestPDF.Examples.Engine;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
+
+namespace QuestPDF.Examples
+{
+    public class RowExamples
+    {
+        [Test]
+        public void Stability()
+        {
+            // up to version 2021.12, this code would always result with the infinite layout exception
+            
+            RenderingTest
+                .Create()
+                .ProducePdf()
+                .MaxPages(100)
+                .PageSize(250, 150)
+                .ShowResults()
+                .Render(container =>
+                {
+                    container
+                        .Padding(25)
+                        .Row(row =>
+                        {
+                            row.RelativeColumn().Stack(stack =>
+                            {
+                                stack.Item().ShowOnce().Element(CreateBox).Text("X");
+                                stack.Item().Element(CreateBox).Text("1");
+                                stack.Item().Element(CreateBox).Text("2");
+                            });
+                                
+                            row.RelativeColumn().Stack(stack =>
+                            {
+                                stack.Item().Element(CreateBox).Text("1");
+                                stack.Item().Element(CreateBox).Text("2");
+                            });
+                        });
+                });
+
+            static IContainer CreateBox(IContainer container)
+            {
+                return container
+                    .ExtendHorizontal()
+                    .ExtendVertical()
+                    .Background(Colors.Grey.Lighten4)
+                    .Border(1)
+                    .AlignCenter()
+                    .AlignMiddle()
+                    .ShowOnce();
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/QuestPDF/Elements/Row.cs b/QuestPDF/Elements/Row.cs
index 7d2b293..8a2c023 100644
--- a/QuestPDF/Elements/Row.cs
+++ b/QuestPDF/Elements/Row.cs
@@ -34,11 +34,20 @@ namespace QuestPDF.Elements
         }
     }
     
-    internal class BinaryRow : Element, ICacheable
+    internal class BinaryRow : Element, ICacheable, IStateResettable
     {
         internal Element Left { get; set; }
         internal Element Right { get; set; }
 
+        private bool IsLeftRendered { get; set; } 
+        private bool IsRightRendered { get; set; } 
+        
+        public void ResetState()
+        {
+            IsLeftRendered = false;
+            IsRightRendered = false;
+        }
+        
         internal override void HandleVisitor(Action<Element?> visit)
         {
             Left.HandleVisitor(visit);
@@ -52,27 +61,34 @@ namespace QuestPDF.Elements
             Left = create(Left);
             Right = create(Right);
         }
-        
+
         internal override SpacePlan Measure(Size availableSpace)
         {
             var leftMeasurement = Left.Measure(new Size(availableSpace.Width, availableSpace.Height));
             
             if (leftMeasurement.Type == SpacePlanType.Wrap)
                 return SpacePlan.Wrap();
+
+            if (leftMeasurement.Type == SpacePlanType.FullRender)
+                IsLeftRendered = true;
             
             var rightMeasurement = Right.Measure(new Size(availableSpace.Width - leftMeasurement.Width, availableSpace.Height));
 
             if (rightMeasurement.Type == SpacePlanType.Wrap)
                 return SpacePlan.Wrap();
             
+            if (leftMeasurement.Type == SpacePlanType.FullRender)
+                IsRightRendered = true;
+            
             var totalWidth = leftMeasurement.Width + rightMeasurement.Width;
             var totalHeight = Math.Max(leftMeasurement.Height, rightMeasurement.Height);
 
             var targetSize = new Size(totalWidth, totalHeight);
 
-            if (leftMeasurement.Type == SpacePlanType.PartialRender || rightMeasurement.Type == SpacePlanType.PartialRender)
+            if ((!IsLeftRendered && leftMeasurement.Type == SpacePlanType.PartialRender) || 
+                (!IsRightRendered && rightMeasurement.Type == SpacePlanType.PartialRender))
                 return SpacePlan.PartialRender(targetSize);
-            
+
             return SpacePlan.FullRender(targetSize);
         }
 
diff --git a/QuestPDF/Infrastructure/Element.cs b/QuestPDF/Infrastructure/Element.cs
index a77f3b8..55b56c5 100644
--- a/QuestPDF/Infrastructure/Element.cs
+++ b/QuestPDF/Infrastructure/Element.cs
@@ -28,10 +28,5 @@ namespace QuestPDF.Infrastructure
         
         internal abstract SpacePlan Measure(Size availableSpace);
         internal abstract void Draw(Size availableSpace);
-
-        protected virtual IEnumerable<string> GetDebugInformation()
-        {
-            yield break;
-        }
     }
 }
\ No newline at end of file