Fixed detecting infinite layout exception in specific cases

QuestPDF.Examples/BarCode.cs

@@ -0,0 +1,32 @@
+using System.IO;
+using NUnit.Framework;
+using QuestPDF.Drawing;
+using QuestPDF.Examples.Engine;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
+
+namespace QuestPDF.Examples
+{
+    public class BarCode
+    {
+        [Test]
+        public void Example()
+        {
+            FontManager.RegisterFontType("LibreBarcode39", File.OpenRead("LibreBarcode39-Regular.ttf"));
+            
+            RenderingTest
+                .Create()
+                .PageSize(400, 100)
+                .FileName()
+                .Render(container =>
+                {
+                    container
+                        .Background(Colors.White)
+                        .AlignCenter()
+                        .AlignMiddle()
+                        .Text("*QuestPDF*", TextStyle.Default.FontType("LibreBarcode39").Size(64));
+                });
+        }
+    }
+}

QuestPDF.Examples/ContinousPage.cs

@@ -0,0 +1,46 @@
+using System.Diagnostics;
+using System.Linq;
+using NUnit.Framework;
+using QuestPDF.Drawing;
+using QuestPDF.Examples.Engine;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
+
+namespace QuestPDF.Examples
+{
+    public class ContinuousPageDocument : IDocument
+    {
+        public DocumentMetadata GetMetadata() => DocumentMetadata.Default;
+
+        public void Compose(IDocumentContainer container)
+        {
+            container.Page(page =>
+            {
+                page.Margin(20);
+                page.ContinuousSize(150);
+                
+                page.Header().Text("Header");
+                
+                page.Content().PaddingVertical(10).Border(1).Padding(10).Stack(stack =>
+                {
+                    foreach (var index in Enumerable.Range(1, 100))
+                        stack.Item().Text($"Line {index}", TextStyle.Default.Color(Placeholders.Color()));
+                });
+                
+                page.Footer().Text("Footer");
+            });
+        }
+    }
+    
+    public class ContinuousPageExamples
+    {
+        [Test]
+        public void ContinuousPage()
+        {
+            var path = "example.pdf";
+            new ContinuousPageDocument().GeneratePdf(path);
+            Process.Start("explorer", path);
+        }
+    }
+}

QuestPDF.Examples/ElementExamples.cs

@@ -755,5 +755,83 @@ namespace QuestPDF.Examples
                         });
                 });
         }
+        
+        [Test]
+        public void ComplexLayout()
+        {
+            RenderingTest
+                .Create()
+                .PageSize(500, 225)
+                .FileName()
+                .Render(container =>
+                {
+                    container
+                        .Padding(25)
+                        .Stack(stack =>
+                        {
+                            stack.Item().Row(row =>
+                            {
+                                row.RelativeColumn().LabelCell("Label 1");
+                                
+                                row.RelativeColumn(3).Grid(grid =>
+                                {
+                                    grid.Columns(3);
+                                    
+                                    grid.Item(2).LabelCell("Label 2");
+                                    grid.Item().LabelCell("Label 3");
+                                    
+                                    grid.Item(2).ValueCell().Text("Value 2");
+                                    grid.Item().ValueCell().Text("Value 3");
+                                });
+                            });
+                            
+                            stack.Item().Row(row =>
+                            {
+                                row.RelativeColumn().ValueCell().Text("Value 1");
+                                
+                                row.RelativeColumn(3).Grid(grid =>
+                                {
+                                    grid.Columns(3);
+                                    
+                                    grid.Item().LabelCell("Label 4");
+                                    grid.Item(2).LabelCell("Label 5");
+                                    
+                                    grid.Item().ValueCell().Text("Value 4");
+                                    grid.Item(2).ValueCell().Text("Value 5");
+                                });
+                            });
+                            
+                            stack.Item().Row(row =>
+                            {
+                                row.RelativeColumn().LabelCell("Label 6");
+                                row.RelativeColumn().ValueCell().Text("Value 6");
+                            });
+                        });
+                });
+        }
+        
+        [Test]
+        public void DomainSpecificLanguage()
+        {
+            RenderingTest
+                .Create()
+                .PageSize(600, 310)
+                .FileName()
+                .Render(container =>
+                {
+                    container
+                        .Padding(25)
+                        .Grid(grid =>
+                        {
+                            grid.Columns(10);
+                            
+                            for(var i=1; i<=4; i++)
+                            {
+                                grid.Item(2).LabelCell(Placeholders.Label());
+                                grid.Item(3).ValueCell().Image(Placeholders.Image(200, 150));
+                            }
+                        });
+                });
+        }
     }
 }

QuestPDF.Examples/FrameExample.cs

@@ -12,11 +12,11 @@ namespace QuestPDF.Examples
         {
             return container
                 .Border(1)
-                .Background(dark ? "#EEE" : "#FFF")
+                .Background(dark ? Colors.Grey.Lighten2 : Colors.White)
                 .Padding(10);
         }
         
-        public static IContainer LabelCell(this IContainer container) => container.Cell(true);
+        public static void LabelCell(this IContainer container, string text) => container.Cell(true).Text(text, TextStyle.Default.Medium());
         public static IContainer ValueCell(this IContainer container) => container.Cell(false);
     }
     
@@ -40,7 +40,7 @@ namespace QuestPDF.Examples
                             {
                                 stack.Item().Row(row =>
                                 {
-                                    row.RelativeColumn(2).LabelCell().Text(Placeholders.Label());
+                                    row.RelativeColumn(2).LabelCell(Placeholders.Label());
                                     row.RelativeColumn(3).ValueCell().Text(Placeholders.Paragraph());
                                 });
                             }

QuestPDF.Examples/QuestPDF.Examples.csproj

@@ -16,4 +16,10 @@
       <ProjectReference Include="..\QuestPDF\QuestPDF.csproj" />
     </ItemGroup>
 
+    <ItemGroup>
+      <None Update="LibreBarcode39-Regular.ttf">
+        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      </None>
+    </ItemGroup>
+
 </Project>

QuestPDF/Drawing/DocumentGenerator.cs

@@ -60,7 +60,10 @@ namespace QuestPDF.Drawing
                 var spacePlan = content.Measure(Size.Max) as Size;
 
                 if (spacePlan == null)
-                    break;
+                {
+                    canvas.EndDocument();
+                    ThrowLayoutException();
+                }
 
                 try
                 {
@@ -78,7 +81,7 @@ namespace QuestPDF.Drawing
                 if (currentPage >= documentMetadata.DocumentLayoutExceptionThreshold)
                 {
                     canvas.EndDocument();
-                    throw new DocumentLayoutException("Composed layout generates infinite document.");
+                    ThrowLayoutException();
                 }
                 
                 if (spacePlan is FullRender)
@@ -88,6 +91,11 @@ namespace QuestPDF.Drawing
             }
             
             canvas.EndDocument();
+            
+            void ThrowLayoutException()
+            {
+                throw new DocumentLayoutException("Composed layout generates infinite document.");
+            }
         }
     }
 }

QuestPDF/Drawing/FontManager.cs

@@ -1,15 +1,23 @@
-using System.Collections.Concurrent;
+using System;
+using System.Collections.Concurrent;
+using System.IO;
 using QuestPDF.Drawing.SpacePlan;
 using QuestPDF.Infrastructure;
 using SkiaSharp;
 
 namespace QuestPDF.Drawing
 {
-    internal static class CanvasCache
+    public static class FontManager
     {
+        private static ConcurrentDictionary<string, SKTypeface> Typefaces = new ConcurrentDictionary<string, SKTypeface>();
         private static ConcurrentDictionary<string, SKPaint> Paints = new ConcurrentDictionary<string, SKPaint>();
         private static ConcurrentDictionary<string, SKPaint> ColorPaint = new ConcurrentDictionary<string, SKPaint>();
 
+        public static void RegisterFontType(string fontName, Stream stream)
+        {
+            Typefaces.TryAdd(fontName, SKTypeface.FromStream(stream));
+        }
+        
         internal static SKPaint ColorToPaint(this string color)
         {
             return ColorPaint.GetOrAdd(color, Convert);
@@ -29,12 +37,10 @@ namespace QuestPDF.Drawing
             
             static SKPaint Convert(TextStyle style)
             {
-                var slant = style.IsItalic ? SKFontStyleSlant.Italic : SKFontStyleSlant.Upright;
-                
                 return new SKPaint
                 {
                     Color = SKColor.Parse(style.Color),
-                    Typeface = SKTypeface.FromFamilyName(style.FontType, (int)style.FontWeight, (int)SKFontStyleWidth.Normal, slant),
+                    Typeface = GetTypeface(style),
                     TextSize = style.Size,
                     TextEncoding = SKTextEncoding.Utf32,
                     
@@ -47,6 +53,17 @@ namespace QuestPDF.Drawing
                     }
                 };
             }
+
+            static SKTypeface GetTypeface(TextStyle style)
+            {
+                if (Typefaces.TryGetValue(style.FontType, out var result))
+                    return result;
+                
+                var slant = style.IsItalic ? SKFontStyleSlant.Italic : SKFontStyleSlant.Upright;
+                
+                return SKTypeface.FromFamilyName(style.FontType, (int)style.FontWeight, (int)SKFontStyleWidth.Normal, slant) 
+                       ?? throw new ArgumentException($"The typeface {style.FontType} could not be found.");
+            }
         }
 
         internal static TextMeasurement BreakText(this TextStyle style, string text, float availableWidth)

QuestPDF/Elements/Page.cs

@@ -1,3 +1,4 @@
+using System;
 using QuestPDF.Fluent;
 using QuestPDF.Helpers;
 using QuestPDF.Infrastructure;
@@ -36,9 +37,20 @@ namespace QuestPDF.Elements
                 .Decoration(decoration =>
                 {
                     decoration.Header().Element(Header);
-                    decoration.Content().Extend().Element(Content);
+                    
+                    decoration
+                        .Content()
+                        .Element(x => IsClose(MinSize.Width, MaxSize.Width) ? x.ExtendHorizontal() : x)
+                        .Element(x => IsClose(MinSize.Height, MaxSize.Height) ? x.ExtendVertical() : x)
+                        .Element(Content);
+                    
                     decoration.Footer().Element(Footer);
                 });
+
+            bool IsClose(float x, float y)
+            {
+                return Math.Abs(x - y) < Size.Epsilon;
+            }
         }
     }
 }

QuestPDF/Elements/Row.cs

@@ -7,29 +7,31 @@ using QuestPDF.Infrastructure;
 
 namespace QuestPDF.Elements
 {
-    internal abstract class RowElement : ContainerElement
+    internal abstract class RowElement : Constrained
     {
-        public float Width { get; set; } = 1;
+        public float Size { get; protected set;  }
         
-        internal override void Draw(Size availableSpace)
+        public void SetWidth(float width)
         {
-            Child?.Draw(availableSpace);
+            MinWidth = width;
+            MaxWidth = width;
         }
     }
     
     internal class ConstantRowElement : RowElement
     {
-        public ConstantRowElement(float width)
+        public ConstantRowElement(float size)
         {
-            Width = width;
+            Size = size;
+            SetWidth(size);
         }
     }
     
     internal class RelativeRowElement : RowElement
     {
-        public RelativeRowElement(float width)
+        public RelativeRowElement(float size)
         {
-            Width = width;
+            Size = size;
         }
     }
     
@@ -84,70 +86,61 @@ namespace QuestPDF.Elements
     
     internal class Row : Element
     {
-        public ICollection<RowElement> Children { get; internal set; } = new List<RowElement>();
         public float Spacing { get; set; } = 0;
-
+        
+        public ICollection<RowElement> Children { get; internal set; } = new List<RowElement>();
+        private Element? RootElement { get; set; }
+        
         internal override void HandleVisitor(Action<Element?> visit)
         {
-            Children.ToList().ForEach(x => x.HandleVisitor(visit));
+            if (RootElement == null)
+                ComposeTree();
+            
+            RootElement.HandleVisitor(visit);
             base.HandleVisitor(visit);
         }
 
         internal override ISpacePlan Measure(Size availableSpace)
         {
-            return Compose(availableSpace.Width).Measure(availableSpace);
+            UpdateElementsWidth(availableSpace.Width);
+            return RootElement.Measure(availableSpace);
         }
 
         internal override void Draw(Size availableSpace)
         {
-            Compose(availableSpace.Width).Draw(availableSpace);
+            UpdateElementsWidth(availableSpace.Width);
+            RootElement.Draw(availableSpace);
         }
         
         #region structure
         
-        private Element Compose(float availableWidth)
+        private void ComposeTree()
         {
-            var elements = AddSpacing(Children, Spacing);
-            var rowElements = ReduceRows(elements, availableWidth);
-            var tree = BuildTree(rowElements.ToArray());
-            tree.HandleVisitor(x => x.Initialize(PageContext, Canvas));
+            Children = AddSpacing(Children, Spacing);
             
-            return tree;
+            var elements = Children.Cast<Element>().ToArray();
+            RootElement = BuildTree(elements);
         }
-        
-        private static ICollection<Element> ReduceRows(ICollection<RowElement> elements, float availableWidth)
+
+        private void UpdateElementsWidth(float availableWidth)
         {
-            var constantWidth = elements
+            var constantWidth = Children
                 .Where(x => x is ConstantRowElement)
                 .Cast<ConstantRowElement>()
-                .Sum(x => x.Width);
+                .Sum(x => x.Size);
         
-            var relativeWidth = elements
+            var relativeWidth = Children
                 .Where(x => x is RelativeRowElement)
                 .Cast<RelativeRowElement>()
-                .Sum(x => x.Width);
+                .Sum(x => x.Size);
 
             var widthPerRelativeUnit = (availableWidth - constantWidth) / relativeWidth;
             
-            return elements
-                .Select(x =>
-                {
-                    if (x is RelativeRowElement r)
-                        return new ConstantRowElement(r.Width * widthPerRelativeUnit)
-                        {
-                            Child = x.Child
-                        };
-                    
-                    return x;
-                })
-                .Select(x => new Constrained
-                {
-                    MinWidth = x.Width,
-                    MaxWidth = x.Width,
-                    Child = x.Child
-                })
-                .Cast<Element>()
-                .ToList();
+            Children
+                .Where(x => x is RelativeRowElement)
+                .Cast<RelativeRowElement>()
+                .ToList()
+                .ForEach(x => x.SetWidth(x.Size * widthPerRelativeUnit));
         }
         
         private static ICollection<RowElement> AddSpacing(ICollection<RowElement> elements, float spacing)

QuestPDF/Fluent/ElementExtensions.cs

@@ -18,10 +18,10 @@ namespace QuestPDF.Fluent
         {
             if (element?.Child != null && element.Child is Empty == false)
             {
-                var message = $"Container {element.GetType().Name} already contains an {element.Child.GetType().Name} child. " +
-                              $"Tried to assign {child?.GetType()?.Name}." +
-                              $"You should not assign multiple elements to single-child containers.";
-                
+                var message = "You should not assign multiple child elements to a single-child container. " +
+                              "This may happen when a container variable is used outside of its scope/closure OR the container is used in multiple fluent API chains OR the container is used incorrectly in a loop. " +
+                              "This exception is thrown to help you detect that some part of the code is overriding fragments of the document layout with a new content - essentially destroying existing content.";
+
                 throw new DocumentComposeException(message);
             }
 

QuestPDF/Fluent/PageExtensions.cs

@@ -12,14 +12,24 @@ namespace QuestPDF.Fluent
 
         public void Size(PageSize pageSize)
         {
-            Page.MinSize = pageSize;
-            Page.MaxSize = pageSize;
+            MinSize(pageSize);
+            MaxSize(pageSize);
         }
-
+        
         public void ContinuousSize(float width)
         {
-            Page.MinSize = new PageSize(width, 0);
-            Page.MaxSize = new PageSize(width, Infrastructure.Size.Max.Height);
+            MinSize(new PageSize(width, 0));
+            MaxSize(new PageSize(width, Infrastructure.Size.Max.Height));
+        }
+
+        public void MinSize(PageSize pageSize)
+        {
+            Page.MinSize = pageSize;
+        }
+        
+        public void MaxSize(PageSize pageSize)
+        {
+            Page.MaxSize = pageSize;
         }
 
         public void MarginLeft(float value)

QuestPDF/QuestPDF.csproj

@@ -4,9 +4,9 @@
         <Authors>MarcinZiabek</Authors>
         <Company>CodeFlint</Company>
         <PackageId>QuestPDF</PackageId>
-        <Version>2021.8</Version>
+        <Version>2021.9.3</Version>
         <PackageDescription>QuestPDF is an open-source, modern and battle-tested library that can help you with generating PDF documents by offering friendly, discoverable and predictable C# fluent API.</PackageDescription>
-        <PackageReleaseNotes>New elements: Unconstrained, Scale, ScaleHorizontal, ScaleVertical, FlipOver, FlipHorizontal, FlipVertical, Rotate, RotateLeft, RotateRight, TranslateX, TranslateY. Added support for more placeholders in the PageNumber element (current page, total number of pages, page number of any predefined location). Added support for documents with various page sizes. Various API improvements.</PackageReleaseNotes>
+        <PackageReleaseNotes>Added support for registering custom fonts from a stream. Fixed continuous page setting. Improved exception messages.</PackageReleaseNotes>
         <LangVersion>8</LangVersion>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
         <PackageIcon>Logo.png</PackageIcon>
@@ -14,8 +14,8 @@
         <PackageProjectUrl>https://www.questpdf.com/</PackageProjectUrl>
         <RepositoryUrl>https://github.com/QuestPDF/library.git</RepositoryUrl>
         <RepositoryType>git</RepositoryType>
-        <Copyright>QuestPDF contributors</Copyright>
-        <PackageTags>PDF file export generate create render portable document format quest free</PackageTags>
+        <Copyright>Marcin Ziąbek, QuestPDF contributors</Copyright>
+        <PackageTags>pdf file export generate generation tool create creation render portable document format quest html library converter free</PackageTags>
         <PackageLicenseExpression>MIT</PackageLicenseExpression>
         <Nullable>enable</Nullable>
         <TargetFrameworks>net462;netstandard2.0;netcoreapp2.0;netcoreapp3.0</TargetFrameworks>