Merge pull request #240 from BobLd/type1-flex

Correct letter bbox for Type1 font/flexpoints - Fix #217

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/Arithmetic/CallOtherSubrCommand.cs

@@ -3,6 +3,8 @@
     using System;
     using System.Collections.Generic;
     using System.Diagnostics;
+    using UglyToad.PdfPig.Core;
+    using UglyToad.PdfPig.Fonts.Type1.CharStrings.Commands.PathConstruction;
 
     /// <summary>
     /// Call other subroutine command. Arguments are pushed onto the PostScript interpreter operand stack then
@@ -23,13 +25,13 @@
 
         public static bool TakeFromStackBottom { get; } = false;
         public static bool ClearsOperandStack { get; } = false;
-        
+
         public static LazyType1Command Lazy { get; } = new LazyType1Command(Name, Run);
 
         public static void Run(Type1BuildCharContext context)
         {
-            var index = (int) context.Stack.PopTop();
-            
+            var index = (int)context.Stack.PopTop();
+
             // What it should do
             var numberOfArguments = (int)context.Stack.PopTop();
             var otherSubroutineArguments = new List<double>(numberOfArguments);
@@ -42,17 +44,44 @@
             {
                 // Other subrs 0-2 implement flex
                 case FlexEnd:
-                {
-                    context.IsFlexing = false;
-                    // TODO: I don't really care about flexpoints, but we should probably handle them... one day.
-                    //if (context.FlexPoints.Count < 7)
-                    //{
-                    //    throw new NotSupportedException("There must be at least 7 flex points defined by an other subroutine.");
-                    //}
+                    {
+                        // https://github.com/apache/pdfbox/blob/2c23d8b4e3ad61852f0b6ee2b95b907eefba1fcf/fontbox/src/main/java/org/apache/fontbox/cff/Type1CharString.java#L339
+                        context.IsFlexing = false;
+                        if (context.FlexPoints.Count < 7)
+                        {
+                            throw new NotSupportedException("There must be at least 7 flex points defined by an other subroutine.");
+                        }
 
-                    context.ClearFlexPoints();
-                    break;
-                }
+                        // reference point is relative to start point
+                        PdfPoint reference = context.FlexPoints[0];
+                        reference = reference.Translate(context.CurrentPosition.X, context.CurrentPosition.Y);
+
+                        // first point is relative to reference point
+                        PdfPoint first = context.FlexPoints[1];
+                        first = first.Translate(reference.X, reference.Y);
+
+                        // make the first point relative to the start point
+                        first = first.Translate(-context.CurrentPosition.X, -context.CurrentPosition.Y);
+
+                        context.Stack.Push(first.X);
+                        context.Stack.Push(first.Y);
+                        context.Stack.Push(context.FlexPoints[2].X);
+                        context.Stack.Push(context.FlexPoints[2].Y);
+                        context.Stack.Push(context.FlexPoints[3].X);
+                        context.Stack.Push(context.FlexPoints[3].Y);
+                        RelativeRCurveToCommand.Run(context);
+
+                        context.Stack.Push(context.FlexPoints[4].X);
+                        context.Stack.Push(context.FlexPoints[4].Y);
+                        context.Stack.Push(context.FlexPoints[5].X);
+                        context.Stack.Push(context.FlexPoints[5].Y);
+                        context.Stack.Push(context.FlexPoints[6].X);
+                        context.Stack.Push(context.FlexPoints[6].Y);
+                        RelativeRCurveToCommand.Run(context);
+
+                        context.ClearFlexPoints();
+                        break;
+                    }
                 case FlexBegin:
                     Debug.Assert(otherSubroutineArguments.Count == 0, "Flex begin should have no arguments.");
 

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/Arithmetic/SetCurrentPointCommand.cs

@@ -4,6 +4,8 @@
 
     /// <summary>
     /// Sets the current point to (x, y) in absolute character space coordinates without performing a charstring moveto command.
+    /// <para>This establishes the current point for a subsequent relative path building command.
+    /// The 'setcurrentpoint' command is used only in conjunction with results from 'OtherSubrs' procedures.</para>
     /// </summary>
     internal static class SetCurrentPointCommand
     {
@@ -22,8 +24,8 @@
             var x = context.Stack.PopBottom();
             var y = context.Stack.PopBottom();
 
-            context.CurrentPosition = new PdfPoint(x, y);
-
+            //context.CurrentPosition = new PdfPoint(x, y);
+            // TODO: need to investigate why odd behavior when the current point is actualy set.
             context.Stack.Clear();
         }
     }

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/PathConstruction/HMoveToCommand.cs

@@ -19,19 +19,19 @@
 
         public static void Run(Type1BuildCharContext context)
         {
-            var x = context.Stack.PopBottom();
-
-            var actualX = context.CurrentPosition.X + x;
-            var y = context.CurrentPosition.Y;
+            var deltaX = context.Stack.PopBottom();
 
             if (context.IsFlexing)
             {
-                // TODO: flex support
+                // not in the Type 1 spec, but exists in some fonts
+                context.AddFlexPoint(new PdfPoint(deltaX, 0));
             }
             else
             {
-                context.CurrentPosition = new PdfPoint(actualX, y);
-                context.Path.MoveTo(actualX, y);
+                var x = context.CurrentPosition.X + deltaX;
+                var y = context.CurrentPosition.Y;
+                context.CurrentPosition = new PdfPoint(x, y);
+                context.Path.MoveTo(x, y);
             }
 
             context.Stack.Clear();

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/PathConstruction/RMoveToCommand.cs

@@ -30,7 +30,7 @@
 
             if (context.IsFlexing)
             {
-                
+                context.AddFlexPoint(new PdfPoint(deltaX, deltaY));
             }
             else
             {

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/PathConstruction/VMoveToCommand.cs

@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Fonts.Type1.CharStrings.Commands.PathConstruction
 {
     using Core;
+    using System;
 
     /// <summary>
     /// Vertical move to. Moves relative to the current point.
@@ -23,7 +24,8 @@
 
             if (context.IsFlexing)
             {
-                // TODO: flex commands
+                // not in the Type 1 spec, but exists in some fonts
+                context.AddFlexPoint(new PdfPoint(0, deltaY));
             }
             else
             {

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/StartFinishOutline/SbwCommand.cs

@@ -6,7 +6,7 @@
     /// Sets left sidebearing and the character width vector.
     /// This command also sets the current point to(sbx, sby), but does not place the point in the character path.
     /// </summary>
-    internal class SbwCommand
+    internal static class SbwCommand
     {
         public const string Name = "sbw";
 

src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Commands/Type1BuildCharContext.cs

@@ -28,7 +28,7 @@
 
         public CharStringStack PostscriptStack { get; } = new CharStringStack();
 
-        public IReadOnlyList<PdfPoint> FlexPoints { get; }
+        public List<PdfPoint> FlexPoints { get; } = new List<PdfPoint>();
 
         public Type1BuildCharContext(IReadOnlyDictionary<int, Type1CharStrings.CommandSequence> subroutines,
             Func<int, PdfSubpath> characterByIndexFactory,
@@ -41,7 +41,7 @@
 
         public void AddFlexPoint(PdfPoint point)
         {
-
+            FlexPoints.Add(point);
         }
 
         public PdfSubpath GetCharacter(int characterCode)
@@ -61,7 +61,7 @@
 
         public void ClearFlexPoints()
         {
-
+            FlexPoints.Clear();
         }
     }
 }

src/UglyToad.PdfPig.Tests/Fonts/Type1/Type1CharStringParserTests.cs

@@ -0,0 +1,39 @@
+using System;
+using System.IO;
+using UglyToad.PdfPig.Core;
+using Xunit;
+
+namespace UglyToad.PdfPig.Tests.Fonts.Type1
+{
+    public class Type1CharStringParserTests
+    {
+        [Fact]
+        public void CorrectBoundingBoxesFlexPoints()
+        {
+            PointComparer pointComparer = new PointComparer(new DoubleComparer(3));
+
+            var documentFolder = Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "..", "..", "..", "Integration", "Documents"));
+
+            var filePath = Path.Combine(documentFolder, "data.pdf");
+
+            using (var doc = PdfDocument.Open(filePath))
+            {
+                var page = doc.GetPage(1);
+
+                var letters = page.Letters;
+
+                // check 'm'
+                var m = letters[0];
+                Assert.Equal("m", m.Value);
+                Assert.Equal(new PdfPoint(253.4458, 658.431), m.GlyphRectangle.BottomLeft, pointComparer);
+                Assert.Equal(new PdfPoint(261.22659, 662.83446), m.GlyphRectangle.TopRight, pointComparer);
+
+                // check 'p'
+                var p = letters[1];
+                Assert.Equal("p", p.Value);
+                Assert.Equal(new PdfPoint(261.70778, 656.49825), p.GlyphRectangle.BottomLeft, pointComparer);
+                Assert.Equal(new PdfPoint(266.6193, 662.83446), p.GlyphRectangle.TopRight, pointComparer);
+            }
+        }
+    }
+}