Expose letter's font via GetFont(), make Font property as obsolete and use FontDetails instead

src/UglyToad.PdfPig.DocumentLayoutAnalysis/DuplicateOverlappingTextProcessor.cs

@@ -68,25 +68,11 @@
                     // update textSequence?
 
                     // update font details to bold
-                    var fontDetails = new FontDetails(letter.Font.Name, true, letter.Font.Weight, letter.Font.IsItalic);
-
-                    var newLetter = new Letter(letter.Value,
-                        letter.GlyphRectangle,
-                        letter.StartBaseLine,
-                        letter.EndBaseLine,
-                        letter.Width,
-                        letter.FontSize,
-                        fontDetails,
-                        letter.RenderingMode,
-                        letter.StrokeColor,
-                        letter.FillColor,
-                        letter.PointSize,
-                        letter.TextSequence);
 
                     // update markedContentStack?
 
                     // update letters
-                    cleanLetters[duplicatesOverlappingIndex] = newLetter;
+                    cleanLetters[duplicatesOverlappingIndex] = letter.AsBold();
                 }
             }
 

src/UglyToad.PdfPig.DocumentLayoutAnalysis/TextExtractor/ContentOrderTextExtractor.cs

@@ -64,7 +64,7 @@
                         letter.EndBaseLine,
                         letter.Width,
                         letter.FontSize,
-                        letter.Font,
+                        letter.GetFont()!,
                         letter.RenderingMode,
                         letter.StrokeColor,
                         letter.FillColor,

src/UglyToad.PdfPig.Tests/Dla/UnsupervisedReadingOrderTests.cs

@@ -1,14 +1,12 @@
 namespace UglyToad.PdfPig.Tests.Dla
 {
-    using System;
+    using PdfFonts;
     using System.Collections.Generic;
     using System.Linq;
-    using System.Text;
-    using System.Threading.Tasks;
     using UglyToad.PdfPig.Content;
+    using UglyToad.PdfPig.Core;
     using UglyToad.PdfPig.DocumentLayoutAnalysis;
     using UglyToad.PdfPig.DocumentLayoutAnalysis.ReadingOrderDetector;
-    using UglyToad.PdfPig.Core;
 
     public class UnsupervisedReadingOrderTests
     {
@@ -65,7 +63,7 @@
                 boundingBox,
                 boundingBox.BottomLeft,
                 boundingBox.BottomRight,
-                10, 1, null, TextRenderingMode.NeitherClip, null, null, 0, 0);// These don't matter
+                10, 1, (FontDetails)null, TextRenderingMode.NeitherClip, null, null, 0, 0);// These don't matter
             var leftTextBlock = new TextBlock(new[] { new TextLine(new[] { new Word(new[] { letter }) }) });
             return leftTextBlock;
         }

src/UglyToad.PdfPig.Tests/Integration/FontDescriptorTests.cs

@@ -86,8 +86,8 @@
                     var letter = page.Letters[l];
                     var expected = DataBoldItalic[l];
                     Assert.Equal((string)expected[0], letter.Value);
-                    Assert.Equal((bool)expected[1], letter.Font.IsBold);
-                    Assert.Equal((bool)expected[2], letter.Font.IsItalic);
+                    Assert.Equal((bool)expected[1], letter.FontDetails.IsBold);
+                    Assert.Equal((bool)expected[2], letter.FontDetails.IsItalic);
                 }
             }
         }

src/UglyToad.PdfPig.Tests/Writer/PdfDocumentBuilderTests.cs

@@ -1154,7 +1154,7 @@
                         {
                             location += letter.Location.X;
                             location += letter.Location.Y;
-                            location += letter.Font.Name.Length;
+                            location += letter.FontDetails.Name.Length;
                         }
                     }
                 }

src/UglyToad.PdfPig/Content/Letter.cs

@@ -54,12 +54,20 @@
         /// <summary>
         /// The name of the font.
         /// </summary>
-        public string? FontName => Font?.Name;
+        public string? FontName => FontDetails?.Name;
 
         /// <summary>
         /// Details about the font for this letter.
         /// </summary>
-        public FontDetails Font { get; }
+        public FontDetails FontDetails { get; }
+
+        /// <summary>
+        /// Details about the font for this letter.
+        /// </summary>
+        [Obsolete("Use FontDetails instead.")]
+        public FontDetails Font => FontDetails;
+
+        private readonly IFont? _font;
 
         /// <summary>
         /// Text rendering mode that indicates whether we should draw this letter's strokes,
@@ -95,17 +103,59 @@
         /// <summary>
         /// Sequence number of the ShowText operation that printed this letter.
         /// </summary>
-        public int TextSequence { get; }
+        public int TextSequence { get; }
 
         /// <summary>
         /// Create a new letter to represent some text drawn by the Tj operator.
         /// </summary>
-        public Letter(string value, PdfRectangle glyphRectangle,
+        public Letter(string value,
+            PdfRectangle glyphRectangle,
             PdfPoint startBaseLine,
             PdfPoint endBaseLine,
             double width,
             double fontSize,
-            FontDetails font,
+            IFont font,
+            TextRenderingMode renderingMode,
+            IColor strokeColor,
+            IColor fillColor,
+            double pointSize,
+            int textSequence) :
+                this(value, glyphRectangle,
+                    startBaseLine, endBaseLine,
+                    width, fontSize, font.Details, font,
+                    renderingMode, strokeColor, fillColor,
+                    pointSize, textSequence)
+        { }
+
+        /// <summary>
+        /// Create a new letter to represent some text drawn by the Tj operator.
+        /// </summary>
+        public Letter(string value,
+            PdfRectangle glyphRectangle,
+            PdfPoint startBaseLine,
+            PdfPoint endBaseLine,
+            double width,
+            double fontSize,
+            FontDetails fontDetails,
+            TextRenderingMode renderingMode,
+            IColor strokeColor,
+            IColor fillColor,
+            double pointSize,
+            int textSequence): 
+                this(value, glyphRectangle,
+                    startBaseLine, endBaseLine,
+                    width, fontSize, fontDetails, null,
+                    renderingMode, strokeColor, fillColor,
+                    pointSize, textSequence)
+        { }
+
+        private Letter(string value, PdfRectangle glyphRectangle,
+            PdfPoint startBaseLine,
+            PdfPoint endBaseLine,
+            double width,
+            double fontSize,
+            FontDetails fontDetails,
+            IFont? font,
             TextRenderingMode renderingMode,
             IColor strokeColor,
             IColor fillColor,
@@ -118,7 +168,8 @@
             EndBaseLine = endBaseLine;
             Width = width;
             FontSize = fontSize;
-            Font = font;
+            FontDetails = fontDetails;
+            _font = font;
             RenderingMode = renderingMode;
             if (renderingMode == TextRenderingMode.Stroke)
             {
@@ -135,6 +186,42 @@
             TextOrientation = GetTextOrientation();
         }
 
+        /// <summary>
+        /// Creates a new <see cref="Letter"/> instance with the same properties as the current instance,
+        /// but with the font details set to bold.
+        /// </summary>
+        /// <returns>
+        /// A new <see cref="Letter"/> instance with bold font details.
+        /// </returns>
+        public Letter AsBold()
+        {
+            return new Letter(Value,
+                GlyphRectangle,
+                StartBaseLine,
+                EndBaseLine,
+                Width,
+                FontSize,
+                FontDetails.AsBold(),
+                _font,
+                RenderingMode,
+                StrokeColor,
+                FillColor,
+                PointSize,
+                TextSequence);
+        }
+
+        /// <summary>
+        /// Retrieves the font associated with this letter, if available.
+        /// </summary>
+        /// <returns>
+        /// The <see cref="IFont"/> instance representing the font used for this letter, 
+        /// or <c>null</c> if no font is associated.
+        /// </returns>
+        public IFont? GetFont()
+        {
+            return _font;
+        }
+        
         private TextOrientation GetTextOrientation()
         {
             if (Math.Abs(StartBaseLine.Y - EndBaseLine.Y) < 10e-5)

src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs

@@ -133,7 +133,7 @@ namespace UglyToad.PdfPig.Graphics
                         attachTo.EndBaseLine,
                         attachTo.Width,
                         attachTo.FontSize,
-                        attachTo.Font,
+                        attachTo.GetFont()!,
                         attachTo.RenderingMode,
                         attachTo.StrokeColor,
                         attachTo.FillColor,
@@ -158,7 +158,7 @@ namespace UglyToad.PdfPig.Graphics
                     transformedPdfBounds.BottomRight,
                     transformedPdfBounds.Width,
                     fontSize,
-                    font.Details,
+                    font,
                     currentState.FontState.TextRenderingMode,
                     currentState.CurrentStrokingColor!,
                     currentState.CurrentNonStrokingColor!,

src/UglyToad.PdfPig/PdfFonts/FontDetails.cs

@@ -3,7 +3,7 @@
     /// <summary>
     /// Summary details of the font used to draw a glyph.
     /// </summary>
-    public class FontDetails
+    public sealed class FontDetails
     {
         /// <summary>
         /// The normal weight for a font.
@@ -35,6 +35,8 @@
         /// </summary>
         public bool IsItalic { get; }
 
+        private readonly Lazy<FontDetails> _bold;
+
         /// <summary>
         /// Create a new <see cref="FontDetails"/>.
         /// </summary>
@@ -44,6 +46,17 @@
             IsBold = isBold;
             Weight = weight;
             IsItalic = isItalic;
+
+            _bold = isBold ? new Lazy<FontDetails>(() => this) : new Lazy<FontDetails>(() => new FontDetails(Name, true, Weight, IsItalic));
+        }
+
+        /// <summary>
+        /// An instance of <see cref="FontDetails"/> with the same properties as the current instance,
+        /// but with the <see cref="IsBold"/> property set to <c>true</c>.
+        /// </summary>
+        public FontDetails AsBold()
+        {
+            return _bold.Value;
         }
 
         internal static FontDetails GetDefault(string? name = null) => new FontDetails(name ?? string.Empty,
@@ -51,7 +64,7 @@
             DefaultWeight,
             false);
 
-        internal FontDetails WithName(string name) => name != null
+        internal FontDetails WithName(string? name) => name is not null
             ? new FontDetails(name, IsBold, Weight, IsItalic)
             : this;