add tests to visually verify the output for glpyh bounding boxes and use advance widths for empty glyphs in truetype fonts

src/UglyToad.PdfPig.Tests/Integration/VisualVerification/GenerateLetterBoundingBoxImages.cs

@@ -0,0 +1,87 @@
+namespace UglyToad.PdfPig.Tests.Integration.VisualVerification
+{
+    using System;
+    using System.Drawing;
+    using System.IO;
+    using Xunit;
+
+    public class GenerateLetterBoundingBoxImages
+    {
+        private const string NonLatinAcrobatDistiller = "Single Page Non Latin - from acrobat distiller";
+        private const string SingleGoogleDrivePage = "Single Page Simple - from google drive";
+        private const string SinglePageFormattedType0Content = "Type0 Font";
+
+        private static string GetFilename(string name)
+        {
+            var documentFolder = Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "..", "..", "..", "Integration", "Documents"));
+
+            if (!name.EndsWith(".pdf"))
+            {
+                name += ".pdf";
+            }
+
+            return Path.Combine(documentFolder, name);
+        }
+
+        [Fact]
+        public void SinglePageNonLatinFromAcrobatDistiller()
+        {
+            Run(NonLatinAcrobatDistiller);
+        }
+
+        [Fact]
+        public void SinglePageSimpleFromGoogleDrive()
+        {
+            Run(SingleGoogleDrivePage);
+        }
+
+        [Fact]
+        public void SinglePageType0Font()
+        {
+            Run(SinglePageFormattedType0Content);
+        }
+
+        private static void Run(string file)
+        {
+            var pdfFileName = GetFilename(file);
+
+            using (var document = PdfDocument.Open(pdfFileName))
+            using (var image = GetCorrespondingImage(pdfFileName))
+            {
+                var page = document.GetPage(1);
+
+                var redPen = new Pen(Color.BlueViolet, 1);
+
+                using (var bitmap = new Bitmap(image))
+                using (var graphics = Graphics.FromImage(bitmap))
+                {
+                    foreach (var word in page.Letters)
+                    {
+                        graphics.DrawRectangle(redPen, new Rectangle((int)word.Rectangle.Left,
+                            792 - (int)word.Rectangle.Top, (int)word.Rectangle.Width, (int)word.Rectangle.Height));
+                    }
+
+                    var imageName = $"{file}.jpg";
+
+                    if (!Directory.Exists("Images"))
+                    {
+                        Directory.CreateDirectory("Images");
+                    }
+
+                    var savePath = Path.Combine("Images", imageName);
+
+                    bitmap.Save(savePath);
+                }
+            }
+        }
+
+        private static Image GetCorrespondingImage(string filename)
+        {
+            var pdf = GetFilename(filename);
+
+            pdf = pdf.Replace(".pdf", ".jpg");
+
+            return Image.FromFile(pdf);
+        }
+    }
+}

src/UglyToad.PdfPig.Tests/UglyToad.PdfPig.Tests.csproj

@@ -31,6 +31,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />
+    <PackageReference Include="System.Drawing.Common" Version="4.5.0-preview2-26406-04" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="xunit.extensibility.execution" Version="2.3.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />

src/UglyToad.PdfPig/Content/Letter.cs

@@ -49,7 +49,7 @@
         /// </summary>
         public override string ToString()
         {
-            return $"{Rectangle} {Value} {FontName} {PointSize}";
+            return $"{Value} {Rectangle} {FontName} {PointSize}";
         }
     }
 }

src/UglyToad.PdfPig/Fonts/Composite/Type0Font.cs

@@ -82,8 +82,6 @@
 
             var fromFont = CidFont.GetWidthFromDictionary(cid);
 
-            var box = GetBoundingBox(characterCode);
-
             return fromFont;
         }
 

src/UglyToad.PdfPig/Fonts/Simple/TrueTypeSimpleFont.cs

@@ -90,7 +90,13 @@ namespace UglyToad.PdfPig.Fonts.Simple
 
         public PdfRectangle GetBoundingBox(int characterCode)
         {
-            return GetFontMatrix().Transform(GetBoundingBoxInGlyphSpace(characterCode));
+            var fontMatrix = GetFontMatrix();
+
+            var boundingBox = GetBoundingBoxInGlyphSpace(characterCode);
+
+            var result = fontMatrix.Transform(boundingBox);
+
+            return result;
         }
 
         private PdfRectangle GetBoundingBoxInGlyphSpace(int characterCode)
@@ -138,3 +144,4 @@ namespace UglyToad.PdfPig.Fonts.Simple
         }
     }
 }
+

src/UglyToad.PdfPig/Fonts/TrueType/Glyphs/Glyph.cs

@@ -24,6 +24,8 @@
 
         public bool IsSimple { get; }
 
+        public bool IsEmpty => Points.Length == 0;
+
         public Glyph(bool isSimple, byte[] instructions, int[] endPointsOfContours, GlyphPoint[] points,
             PdfRectangle bounds)
         {

src/UglyToad.PdfPig/Fonts/TrueType/Glyphs/IGlyphDescription.cs

@@ -14,6 +14,8 @@
 
         GlyphPoint[] Points { get; }
 
+        bool IsEmpty { get; }
+
         IGlyphDescription DeepClone();
     }
 

src/UglyToad.PdfPig/Fonts/TrueType/TrueTypeFont.cs

@@ -20,14 +20,9 @@
 
         public TrueTypeFont(decimal version, IReadOnlyDictionary<string, TrueTypeHeaderTable> tableHeaders, TableRegister tableRegister)
         {
-            if (tableRegister == null)
-            {
-                throw new ArgumentNullException(nameof(tableRegister));
-            }
-
             Version = version;
             TableHeaders = tableHeaders;
-            TableRegister = tableRegister;
+            TableRegister = tableRegister ?? throw new ArgumentNullException(nameof(tableRegister));
             HeaderTable = tableRegister.HeaderTable;
             CMapTable = tableRegister.CMapTable;
             GlyphTable = tableRegister.GlyphDataTable;
@@ -38,18 +33,7 @@
         {
             boundingBox = default(PdfRectangle);
 
-            int index;
-
-            if (CMapTable == null)
-            {
-                if (characterIdentifierToGlyphIndex == null)
-                {
-                    return false;
-                }
-
-                index = characterIdentifierToGlyphIndex(characterCode);
-            }
-            else if (!CMapTable.TryGetGlyphIndex(characterCode, out index))
+            if (!TryGetGlyphIndex(characterCode, characterIdentifierToGlyphIndex, out var index))
             {
                 return false;
             }
@@ -61,8 +45,15 @@
                 return false;
             }
 
-            boundingBox = glyph.Bounds;
-
+            if (glyph.IsEmpty && TryGetBoundingAdvancedWidthByIndex(index, out var advanceWidth))
+            {
+                boundingBox = new PdfRectangle(0, 0, advanceWidth, 0);
+            }
+            else
+            {
+                boundingBox = glyph.Bounds;
+            }
+            
             return true;
         }
 
@@ -70,18 +61,39 @@
         {
             width = 0m;
 
+            if (!TryGetGlyphIndex(characterCode, null, out var index))
+            {
+                return false;
+            }
+
+            return TryGetBoundingAdvancedWidthByIndex(index, out width);
+        }
+
+        private bool TryGetBoundingAdvancedWidthByIndex(int index, out decimal width)
+        {
+            width = TableRegister.HorizontalMetricsTable.GetAdvanceWidth(index);
+
+            return true;
+        }
+
+        private bool TryGetGlyphIndex(int characterIdentifier, Func<int, int> characterIdentifierToGlyphIndex, out int glyphIndex)
+        {
+            glyphIndex = 0;
+
             if (CMapTable == null)
             {
-                return false;
-            }
+                if (characterIdentifierToGlyphIndex == null)
+                {
+                    return false;
+                }
 
-            if (!CMapTable.TryGetGlyphIndex(characterCode, out var index))
+                glyphIndex = characterIdentifierToGlyphIndex(characterIdentifier);
+            }
+            else if (!CMapTable.TryGetGlyphIndex(characterIdentifier, out glyphIndex))
             {
                 return false;
             }
 
-            width = TableRegister.HorizontalMetricsTable.GetAdvanceWidth(index);
-
             return true;
         }
     }