prepare type 1 private dictionary for public api. fix typo

src/UglyToad.PdfPig/Fonts/Type1/MinFeature.cs

@@ -0,0 +1,40 @@
+namespace UglyToad.PdfPig.Fonts.Type1
+{
+    /// <summary>
+    /// Represents the <see cref="Type1PrivateDictionary"/> MinFeature entry which is required for compatibility
+    /// and must have the value 16, 16.
+    /// </summary>
+    internal class MinFeature
+    {
+        /// <summary>
+        /// The first value.
+        /// </summary>
+        public int First { get; }
+
+        /// <summary>
+        /// The second value.
+        /// </summary>
+        public int Second { get; }
+
+        /// <summary>
+        /// The required default value of <see cref="MinFeature"/>.
+        /// </summary>
+        public static MinFeature Default { get; } = new MinFeature(16, 16);
+
+        /// <summary>
+        /// Creates a <see cref="MinFeature"/> array.
+        /// </summary>
+        /// <param name="first">The first value.</param>
+        /// <param name="second">The second value.</param>
+        public MinFeature(int first, int second)
+        {
+            First = first;
+            Second = second;
+        }
+
+        public override string ToString()
+        {
+            return $"{{{First} {Second}}}";
+        }
+    }
+}

src/UglyToad.PdfPig/Fonts/Type1/Parser/Type1EncryptedPortionParser.cs

@@ -131,7 +131,7 @@
                     case Type1Symbols.StemSnapHorizontalWidths:
                         {
                             var widths = ReadArrayValues(tokenizer, x => x.AsDecimal());
-                            builder.StempSnapHorizontalWidths = widths;
+                            builder.StemSnapHorizontalWidths = widths;
                             break;
                         }
                     case Type1Symbols.StemSnapVerticalWidths:
@@ -168,7 +168,7 @@
                                 }
                             }
 
-                            builder.MinFeature = new Type1PrivateDictionary.MinFeature(procedureTokens[0].AsInt(), procedureTokens[1].AsInt());
+                            builder.MinFeature = new MinFeature(procedureTokens[0].AsInt(), procedureTokens[1].AsInt());
 
                             ReadTillDef(tokenizer);
 

src/UglyToad.PdfPig/Fonts/Type1/Type1PrivateDictionary.cs

@@ -1,72 +1,326 @@
 namespace UglyToad.PdfPig.Fonts.Type1
 {
+    using System;
     using System.Collections.Generic;
     using Parser;
 
+    /// <summary>
+    /// The Private dictionary for a Type 1 font contains hints that apply across all characters in the font. These hints
+    /// help preserve properties of character outline shapes when rendered at smaller sizes and lower resolutions.
+    /// These hints help ensure that the shape is as close as possible to the original design even where the character
+    /// must be represented in few pixels.
+    /// Note that subroutines are also defined in the private dictionary however for the purposes of this API they are
+    /// stored on the parent <see cref="Type1Font"/>.
+    /// </summary>
     internal class Type1PrivateDictionary
     {
-        public class Builder
+        /// <summary>
+        /// Default value of <see cref="BlueScale"/>.
+        /// </summary>
+        public static readonly decimal DefaultBlueScale = 0.039625m;
+
+        /// <summary>
+        /// Default value of <see cref="ExpansionFactor"/>.
+        /// </summary>
+        public static readonly decimal DefaultExpansionFactor = 0.06m;
+
+        /// <summary>
+        /// Default value of <see cref="BlueFuzz"/>.
+        /// </summary>
+        public const int DefaultBlueFuzz = 1;
+        
+        /// <summary>
+        /// Default value of <see cref="BlueShift"/>.
+        /// </summary>
+        public const int DefaultBlueShift = 7;
+
+        /// <summary>
+        /// Default value of <see cref="LanguageGroup"/>.
+        /// </summary>
+        public const int DefaultLanguageGroup = 0;
+
+        /// <summary>
+        /// Optional: Uniquely identifies this font.
+        /// </summary>
+        public int? UniqueId { get; set; }
+
+        /// <summary>
+        /// Required. An array containing an even number of integers.
+        /// The first pair is the baseline overshoot position and the baseline.
+        /// All following pairs describe top-zones.
+        /// </summary>
+        public IReadOnlyList<int> BlueValues { get; }
+
+        /// <summary>
+        /// Optional: Pairs of integers similar to <see cref="BlueValues"/>.
+        /// These only describe bottom zones.
+        /// </summary>
+        public IReadOnlyList<int> OtherBlues { get; }
+
+        /// <summary>
+        /// Optional: Integer pairs similar to <see cref="BlueValues"/> however these
+        /// are used to enforce consistency across a font family when there are small differences (&lt;1px) in
+        /// font alignment.
+        /// </summary>
+        public IReadOnlyList<int> FamilyBlues { get; }
+
+        /// <summary>
+        /// Optional: Integer pairs similar to <see cref="OtherBlues"/> however these
+        /// are used to enforce consistency across a font family with small differences 
+        /// in alignment similarly to <see cref="FamilyBlues"/>.
+        /// </summary>
+        public IReadOnlyList<int> FamilyOtherBlues { get; }
+
+        /// <summary>
+        /// Optional: The point size at which overshoot suppression stops.
+        /// The value is a related to the number of pixels tall that one character space unit will be
+        /// before overshoot suppression is switched off. Overshoot suppression enforces features to snap
+        /// to alignment zones when the point size is below that affected by this value.
+        /// Default: 0.039625
+        /// </summary>
+        /// <example>
+        /// A blue scale of 0.039625 switches overshoot suppression off at 10 points
+        /// on a 300 dpi device using the formula (for 300 dpi):
+        /// BlueScale = (pointsize - 0.49)/240
+        /// For example, if you wish overshoot suppression to turn off at 11
+        /// points on a 300-dpi device, you should set BlueScale to
+        /// (11 − 0.49) ÷ 240 or 0.04379
+        /// </example>
+        public decimal BlueScale { get; }
+
+        /// <summary>
+        /// Optional: The character space distance beyond the flat position of alignment zones
+        /// at which overshoot enforcement occurs.
+        /// Default: 7
+        /// </summary>
+        public int BlueShift { get; }
+
+        /// <summary>
+        /// Optional: The number of character space units to extend an alignment zone
+        /// on a horizontal stem.
+        /// If the top or bottom of a horizontal stem is within BlueFuzz units outside a top-zone
+        /// then the stem top/bottom is treated as if it were within the zone.
+        /// Default: 1
+        /// </summary>
+        public int BlueFuzz { get; }
+
+        /// <summary>
+        /// Optional: The dominant width of horizontal stems vertically in character space units.
+        /// </summary>
+        public decimal? StandardHorizontalWidth { get; }
+
+        /// <summary>
+        /// Optional: The dominant width of vertical stems horizontally in character space units.
+        /// </summary>
+        public decimal? StandardVerticalWidth { get; }
+
+        /// <summary>
+        /// Optional: Up to 12 numbers with the most common widths for horizontal stems vertically in character space units.
+        /// </summary>
+        public IReadOnlyList<decimal> StemSnapHorizontalWidths { get; }
+        
+        /// <summary>
+        /// Optional: Up to 12 numbers with the most common widths for vertical stems horizontally in character space units.
+        /// </summary>
+        public IReadOnlyList<decimal> StemSnapVerticalWidths { get; }
+
+        /// <summary>
+        /// Optional: At small sizes at low resolutions this controls whether bold characters should appear thicker using
+        /// special techniques.
+        /// </summary>
+        public bool ForceBold { get; }
+
+        /// <summary>
+        /// Optional: Language group 0 includes Latin, Greek and Cyrillic as well as similar alphabets.
+        /// Language group 1 includes Chinese, Japanese Kanji and Korean Hangul as well as similar alphabets.
+        /// If language group is 1 then <see cref="RoundStemUp"/> should also be set.
+        /// Default: 0
+        /// </summary>
+        public int LanguageGroup { get; }
+
+        /// <summary>
+        /// Optional: Indicates the number of random bytes used for charstring encryption/decryption.
+        /// Default: 4
+        /// </summary>
+        public int LenIv { get; }
+
+        /// <summary>
+        /// Optional: Preserved for backwards compatibility. Must be set if the <see cref="LanguageGroup"/> is 1.
+        /// </summary>
+        public bool? RoundStemUp { get; }
+
+        /// <summary>
+        /// Optional: The limit for changing the size of a character bounding box for
+        /// <see cref="LanguageGroup"/> 1 counters during font processing.
+        /// </summary>
+        public decimal ExpansionFactor { get; }
+
+        /// <summary>
+        /// Required: Backwards compatibility.
+        /// Default: 5839
+        /// </summary>
+        public int Password { get; } = 5839;
+
+        /// <summary>
+        /// Required: Backwards compatibility.
+        /// Default: {16 16}
+        /// </summary>
+        public MinFeature MinFeature { get; } = new MinFeature(16, 16);
+
+        /// <summary>
+        /// Creates a new <see cref="Type1PrivateDictionary"/>.
+        /// </summary>
+        /// <param name="builder">The builder used to gather property values.</param>
+        public Type1PrivateDictionary(Builder builder)
         {
-            public object Rd { get; set; }
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
 
-            public object NoAccessPut { get; set; }
-
-            public object NoAccessDef { get; set; }
-
-            public IReadOnlyList<Type1CharstringDecryptedBytes> Subroutines { get; set; }
-
-            public object[] OtherSubroutines { get; set; }
-
-            public int? UniqueId { get; set; }
-
-            public IReadOnlyList<int> BlueValues { get; set; }
-
-            public IReadOnlyList<int> OtherBlues { get; set; }
-
-            public IReadOnlyList<int> FamilyBlues { get; set; }
-
-            public IReadOnlyList<int> FamilyOtherBlues { get; set; }
-
-            public decimal? BlueScale { get; set; }
-
-            public int? BlueShift { get; set; }
-
-            public int? BlueFuzz { get; set; }
-
-            public decimal? StandardHorizontalWidth { get; set; }
-
-            public decimal? StandardVerticalWidth { get; set; }
-
-            public IReadOnlyList<decimal> StempSnapHorizontalWidths { get; set; }
-
-            public IReadOnlyList<decimal> StemSnapVerticalWidths { get; set; }
-
-            public bool ForceBold { get; set; }
-
-            public int LanguageGroup { get; set; }
-
-            public int? Password { get; set; }
-
-            public int LenIv { get; set; }
-
-            public MinFeature MinFeature { get; set; }
-
-            public bool RoundStemUp { get; set; }
-
-            public decimal? ExpansionFactor { get; set; }
+            UniqueId = builder.UniqueId;
+            BlueValues = builder.BlueValues ?? Array.Empty<int>();
+            OtherBlues = builder.OtherBlues ?? Array.Empty<int>();
+            FamilyBlues = builder.FamilyBlues ?? Array.Empty<int>();
+            FamilyOtherBlues = builder.FamilyOtherBlues ?? Array.Empty<int>();
+            BlueScale = builder.BlueScale ?? DefaultBlueScale;
+            BlueFuzz = builder.BlueFuzz ?? DefaultBlueFuzz;
+            BlueShift = builder.BlueShift ?? DefaultBlueShift;
+            StandardHorizontalWidth = builder.StandardHorizontalWidth;
+            StandardVerticalWidth = builder.StandardVerticalWidth;
+            StemSnapHorizontalWidths = builder.StemSnapHorizontalWidths ?? Array.Empty<decimal>();
+            StemSnapVerticalWidths = builder.StemSnapVerticalWidths ?? Array.Empty<decimal>();
+            ForceBold = builder.ForceBold ?? false;
+            LanguageGroup = builder.LanguageGroup ?? DefaultLanguageGroup;
+            RoundStemUp = builder.RoundStemUp;
+            LenIv = builder.LenIv;
+            ExpansionFactor = builder.ExpansionFactor ?? DefaultExpansionFactor;
         }
 
-        public class MinFeature
+        /// <summary>
+        /// A mutable builder which can set any property of the private dictionary and performs no validation.
+        /// </summary>
+        public class Builder
         {
-            public int First { get; }
+            /// <summary>
+            /// Temporary storage for the Rd procedure tokens.
+            /// </summary>
+            public object Rd { get; set; }
 
-            public int Second { get; }
+            /// <summary>
+            /// Temporary storage for the No Access Put procedure tokens.
+            /// </summary>
+            public object NoAccessPut { get; set; }
 
-            public MinFeature(int first, int second)
-            {
-                First = first;
-                Second = second;
-            }
+            /// <summary>
+            /// Temporary storage for the No Access Def procedure tokens.
+            /// </summary>
+            public object NoAccessDef { get; set; }
+
+            /// <summary>
+            /// Temporary storage for the decrypted but raw bytes of the subroutines in this private dictionary.
+            /// </summary>
+            public IReadOnlyList<Type1CharstringDecryptedBytes> Subroutines { get; set; }
+
+            /// <summary>
+            /// Temporary storage for the tokens of the other subroutine procedures.
+            /// </summary>
+            public object[] OtherSubroutines { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.UniqueId"/>.
+            /// </summary>
+            public int? UniqueId { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.BlueValues"/>.
+            /// </summary>
+            public IReadOnlyList<int> BlueValues { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.OtherBlues"/>.
+            /// </summary>
+            public IReadOnlyList<int> OtherBlues { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.FamilyBlues"/>.
+            /// </summary>
+            public IReadOnlyList<int> FamilyBlues { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.FamilyOtherBlues"/>.
+            /// </summary>
+            public IReadOnlyList<int> FamilyOtherBlues { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.BlueScale"/>.
+            /// </summary>
+            public decimal? BlueScale { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.BlueShift"/>.
+            /// </summary>
+            public int? BlueShift { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.BlueFuzz"/>.
+            /// </summary>
+            public int? BlueFuzz { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.StandardVerticalWidth"/>.
+            /// </summary>
+            public decimal? StandardHorizontalWidth { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.StandardVerticalWidth"/>.
+            /// </summary>
+            public decimal? StandardVerticalWidth { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.StemSnapHorizontalWidths"/>.
+            /// </summary>
+            public IReadOnlyList<decimal> StemSnapHorizontalWidths { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.StemSnapVerticalWidths"/>.
+            /// </summary>
+            public IReadOnlyList<decimal> StemSnapVerticalWidths { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.ForceBold"/>.
+            /// </summary>
+            public bool? ForceBold { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.LanguageGroup"/>.
+            /// </summary>
+            public int? LanguageGroup { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.Password"/>.
+            /// </summary>
+            public int? Password { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.LenIv"/>.
+            /// </summary>
+            public int LenIv { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.MinFeature"/>.
+            /// </summary>
+            public MinFeature MinFeature { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.RoundStemUp"/>.
+            /// </summary>
+            public bool? RoundStemUp { get; set; }
+
+            /// <summary>
+            /// <see cref="Type1PrivateDictionary.ExpansionFactor"/>.
+            /// </summary>
+            public decimal? ExpansionFactor { get; set; }
         }
     }
 }