Simplify path construction operators

fix 're' operator to reflect documentation
Update ContentStreamProcessor with fill, stroke and clip operations
Throw errors when currentPosition is null in PdfSubpath

src/UglyToad.PdfPig.Core/PdfSubpath.cs

@@ -166,8 +166,8 @@
             }
             else
             {
-                // TODO: probably the wrong behaviour here, maybe line starts from (0, 0)?
-                MoveTo(x, y);
+                // PDF Reference 1.7 p226
+                throw new ArgumentNullException("LineTo(): currentPosition is null.");
             }
         }
         
@@ -176,11 +176,12 @@
         /// </summary>
         public void Rectangle(double x, double y, double width, double height)
         {
-            currentPosition = new PdfPoint(x, y);
-            LineTo(x + width, y);
-            LineTo(x + width, y + height);
-            LineTo(x, y + height);
-            LineTo(x, y);
+                                                // is equivalent to
+            MoveTo(x, y);                       // x y m
+            LineTo(x + width, y);               // (x + width) y l
+            LineTo(x + width, y + height);      // (x + width) (y + height) l
+            LineTo(x, y + height);              // x (y + height) l
+            ClosePath();                        // h
             IsDrawnAsRectangle = true;
         }
         
@@ -203,7 +204,8 @@
             }
             else
             {
-                MoveTo(x3, y3);
+                // PDF Reference 1.7 p226
+                throw new ArgumentNullException("BezierCurveTo(): currentPosition is null.");
             }
         }
         

src/UglyToad.PdfPig.Tests/Graphics/TestOperationContext.cs

@@ -64,6 +64,15 @@
 
         public void BeginSubpath()
         {
+        }
+        public PdfPoint CloseSubpath()
+        {
+            return new PdfPoint();
+        }
+
+        public void AddCurrentSubpath()
+        {
+
         }
 
         public void StrokePath(bool close)

src/UglyToad.PdfPig/Content/ArtifactMarkedContentElement.cs

@@ -1,8 +1,9 @@
 namespace UglyToad.PdfPig.Content
 {
-    using System.Collections.Generic;
     using Core;
+    using System.Collections.Generic;
     using Tokens;
+    using UglyToad.PdfPig.Graphics;
 
     /// <inheritdoc />
     /// <summary>
@@ -73,7 +74,7 @@
             IReadOnlyList<NameToken> attached,
             IReadOnlyList<MarkedContentElement> children,
             IReadOnlyList<Letter> letters,
-            IReadOnlyList<PdfSubpath> paths,
+            IReadOnlyList<PdfPath> paths,
             IReadOnlyList<IPdfImage> images,
             int index) 
             : base(markedContentIdentifier, tag, properties, language,

src/UglyToad.PdfPig/Content/MarkedContentElement.cs

@@ -2,8 +2,8 @@
 {
     using System;
     using System.Collections.Generic;
-    using Core;
     using Tokens;
+    using UglyToad.PdfPig.Graphics;
 
     /// <summary>
     /// A marked content element can be used to provide application specific data in the
@@ -50,7 +50,7 @@
         /// <summary>
         /// Paths contained in this marked content.
         /// </summary>
-        public IReadOnlyList<PdfSubpath> Paths { get; }
+        public IReadOnlyList<PdfPath> Paths { get; }
 
         /// <summary>
         /// Images contained in this marked content.
@@ -88,7 +88,7 @@
             bool isArtifact, 
             IReadOnlyList<MarkedContentElement> children,
             IReadOnlyList<Letter> letters,
-            IReadOnlyList<PdfSubpath> paths,
+            IReadOnlyList<PdfPath> paths,
             IReadOnlyList<IPdfImage> images,
                 int index)
         {

src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs

@@ -412,7 +412,7 @@
                 CurrentPath = new PdfPath();
             }
 
-            AddSubpath();
+            AddCurrentSubpath();
             CurrentSubpath = new PdfSubpath();
         }
 
@@ -429,11 +429,11 @@
             }
 
             CurrentSubpath.ClosePath();
-            AddSubpath();
+            AddCurrentSubpath();
             return point;
         }
 
-        public void AddSubpath()
+        public void AddCurrentSubpath()
         {
             if (CurrentSubpath == null)
             {
@@ -446,22 +446,149 @@
 
         public void StrokePath(bool close)
         {
+            if (CurrentPath == null)
+            {
+                throw new ArgumentException("StrokePath(null)");
+                //return;
+            }
 
+            CurrentPath.SetStroked();
+
+            if (close)
+            {
+                CurrentSubpath.ClosePath();
+            }
+
+            ClosePath();
         }
 
         public void FillPath(FillingRule fillingRule, bool close)
         {
+            if (CurrentPath == null)
+            {
+                throw new ArgumentException("FillPath(null)");
+                //return;
+            }
 
+            CurrentPath.SetFilled(fillingRule);
+
+            if (close)
+            {
+                CurrentSubpath.ClosePath();
+            }
+
+            ClosePath();
         }
 
         public void FillStrokePath(FillingRule fillingRule, bool close)
         {
-            
+            if (CurrentPath == null)
+            {
+                throw new ArgumentException("FillStrokePath(null)");
+                //return;
+            }
+
+            CurrentPath.SetFilled(fillingRule);
+            CurrentPath.SetStroked();
+
+            if (close)
+            {
+                CurrentSubpath.ClosePath();
+            }
+
+            ClosePath();
         }
         
+        /// <summary>
+        /// End the path object without filling or stroking it. This operator shall be a path-painting no-op,
+        /// used primarily for the side effect of changing the current clipping path (see 8.5.4, "Clipping Path Operators").
+        /// </summary>
+        public void EndPath()
+        {
+            AddCurrentSubpath();
+
+            if (CurrentPath.IsClipping)
+            {
+                /*if (!clipPaths)
+                {
+                    // if we don't clip paths, add clipping paths
+                    paths.Add(CurrentPath);
+                    markedContentStack.AddPath(CurrentPath);
+                }*/
+                CurrentPath = null;
+                return;
+            }
+
+            paths.Add(CurrentPath);
+            markedContentStack.AddPath(CurrentPath);
+            CurrentPath = null;
+        }
+
         public void ClosePath()
         {
+            AddCurrentSubpath();
 
+            if (CurrentPath.IsClipping)
+            {
+                EndPath();
+                return;
+            }
+
+            var currentState = this.GetCurrentState();
+            if (CurrentPath.IsStroked)
+            {
+                CurrentPath.LineDashPattern = currentState.LineDashPattern;
+                CurrentPath.StrokeColor = currentState.CurrentStrokingColor;
+                CurrentPath.LineWidth = currentState.LineWidth;
+                CurrentPath.LineCapStyle = currentState.CapStyle;
+                CurrentPath.LineJoinStyle = currentState.JoinStyle;
+            }
+
+            if (CurrentPath.IsFilled)
+            {
+                CurrentPath.FillColor = currentState.CurrentNonStrokingColor;
+            }
+
+            //if (clipPaths)
+            //{
+                var clippedPath = currentState.CurrentClippingPath.Clip(CurrentPath);
+                if (clippedPath != null)
+                {
+                    paths.Add(clippedPath);
+                    markedContentStack.AddPath(clippedPath);
+                }
+            /*}
+            else
+            {
+                paths.Add(CurrentPath);
+                markedContentStack.AddPath(CurrentPath);
+            }*/
+
+            CurrentPath = null;
+        }
+        public void ModifyClippingIntersect(FillingRule clippingRule)
+        {
+            if (CurrentPath == null)
+            {
+                throw new ArgumentException("ModifyClippingIntersect(null)");
+            }
+
+            AddCurrentSubpath();
+
+            CurrentPath.SetClipping(clippingRule);
+            var currentClipping = GetCurrentState().CurrentClippingPath;
+            currentClipping.SetClipping(clippingRule);
+
+            var newClippings = CurrentPath.Clip(currentClipping);
+            if (newClippings == null)
+            {
+                Console.WriteLine("ContentStreamProcessor.ModifyClippingIntersect(): Warning, empty clipping path found... Clipping path not updated.");
+                log.Warn("ModifyClippingIntersect(): Warning, empty clipping path found... Clipping path not updated.");
+            }
+            else
+            {
+                GetCurrentState().CurrentClippingPath = newClippings;
+            }
         }
 
         public void SetNamedGraphicsState(NameToken stateName)
@@ -563,15 +690,5 @@
 
             TextMatrices.TextMatrix = newMatrix;
         }
-
-        public void ModifyClippingIntersect(FillingRule clippingRule)
-        {
-            if (CurrentSubpath == null)
-            {
-                return;
-            }
-
-
-        }
     }
 }

src/UglyToad.PdfPig/Graphics/IOperationContext.cs

@@ -85,6 +85,17 @@
         /// Start a new sub-path.
         /// </summary>
         void BeginSubpath();
+        
+        /// <summary>
+        /// Close the current subpath.
+        /// </summary>
+        /// <returns></returns>
+        PdfPoint CloseSubpath();
+
+        /// <summary>
+        /// Add the current subpath to the path.
+        /// </summary>
+        void AddCurrentSubpath();
 
         /// <summary>
         /// Stroke the current path.

src/UglyToad.PdfPig/Graphics/MarkedContentStack.cs

@@ -57,7 +57,7 @@
             top?.AddLetter(letter);
         }
 
-        public void AddPath(PdfSubpath path)
+        public void AddPath(PdfPath path)
         {
             top?.AddPath(path);
         }
@@ -86,7 +86,7 @@
             private readonly DictionaryToken properties;
 
             private readonly List<Letter> letters = new List<Letter>();
-            private readonly List<PdfSubpath> paths = new List<PdfSubpath>();
+            private readonly List<PdfPath> paths = new List<PdfPath>();
             private readonly List<IPdfImage> images = new List<IPdfImage>();
 
             public List<MarkedContentElement> Children { get; } = new List<MarkedContentElement>();
@@ -108,7 +108,7 @@
                 images.Add(image);
             }
 
-            public void AddPath(PdfSubpath path)
+            public void AddPath(PdfPath path)
             {
                 paths.Add(path);
             }

src/UglyToad.PdfPig/Graphics/Operations/PathConstruction/AppendDualControlPointBezierCurve.cs

@@ -71,17 +71,12 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            var controlPoint1 = new PdfPoint(X1, Y1);
-            var controlPoint2 = new PdfPoint(X2, Y2);
-            var end = new PdfPoint(X3, Y3);
-
-            var controlPoint1Transform = operationContext.CurrentTransformationMatrix.Transform(controlPoint1);
-            var controlPoint2Transform = operationContext.CurrentTransformationMatrix.Transform(controlPoint2);
-            var endTransform = operationContext.CurrentTransformationMatrix.Transform(end);
-            operationContext.CurrentSubpath.BezierCurveTo(controlPoint1Transform.X, controlPoint1Transform.Y,
-                controlPoint2Transform.X, controlPoint2Transform.Y,
-                endTransform.X, endTransform.Y);
-            operationContext.CurrentPosition = endTransform;
+            var controlPoint1 = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(X1, Y1));
+            var controlPoint2 = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(X2, Y2));
+            var end = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(X3, Y3));
+            operationContext.CurrentSubpath.BezierCurveTo(controlPoint1.X, controlPoint1.Y,
+                controlPoint2.X, controlPoint2.Y, end.X, end.Y);
+            operationContext.CurrentPosition = end;
         }
 
         /// <inheritdoc />

src/UglyToad.PdfPig/Graphics/Operations/PathConstruction/AppendEndControlPointBezierCurve.cs

@@ -56,16 +56,10 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            var controlPoint1 = new PdfPoint(X1, Y1);
-            var end = new PdfPoint(X3, Y3);
-            var controlPoint1Transform = operationContext.CurrentTransformationMatrix.Transform(controlPoint1);
-            var endTransform = operationContext.CurrentTransformationMatrix.Transform(end);
-            operationContext.CurrentSubpath.BezierCurveTo(controlPoint1Transform.X, controlPoint1Transform.Y,
-                endTransform.X,
-                endTransform.Y,
-                endTransform.X,
-                endTransform.Y);
-            operationContext.CurrentPosition = endTransform;
+            var controlPoint1 = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(X1, Y1));
+            var end = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(X3, Y3));
+            operationContext.CurrentSubpath.BezierCurveTo(controlPoint1.X, controlPoint1.Y, end.X, end.Y, end.X, end.Y);
+            operationContext.CurrentPosition = end;
         }
 
         /// <inheritdoc />

src/UglyToad.PdfPig/Graphics/Operations/PathConstruction/AppendRectangle.cs

@@ -56,14 +56,12 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            var lowerLeft = new PdfPoint(LowerLeftX, LowerLeftY);
-            var upperRight = new PdfPoint(LowerLeftX + Width, LowerLeftY + Height);
-
             operationContext.BeginSubpath();
-            var lowerLeftTransform = operationContext.CurrentTransformationMatrix.Transform(lowerLeft);
-            var upperRightTransform = operationContext.CurrentTransformationMatrix.Transform(upperRight);
+            var lowerLeft = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(LowerLeftX, LowerLeftY));
+            var upperRight = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(LowerLeftX + Width, LowerLeftY + Height));
 
-            operationContext.CurrentSubpath.Rectangle(lowerLeftTransform.X, lowerLeftTransform.Y, upperRightTransform.X - lowerLeftTransform.X, upperRightTransform.Y - lowerLeftTransform.Y);
+            operationContext.CurrentSubpath.Rectangle(lowerLeft.X, lowerLeft.Y, upperRight.X - lowerLeft.X, upperRight.Y - lowerLeft.Y);
+            operationContext.AddCurrentSubpath();
         }
 
         /// <inheritdoc />

src/UglyToad.PdfPig/Graphics/Operations/PathConstruction/BeginNewSubpath.cs

@@ -41,11 +41,10 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            var point = new PdfPoint(X, Y);
             operationContext.BeginSubpath();
-            var pointTransform = operationContext.CurrentTransformationMatrix.Transform(point);
-            operationContext.CurrentPosition = pointTransform;
-            operationContext.CurrentSubpath.MoveTo(pointTransform.X, pointTransform.Y);
+            var point = operationContext.CurrentTransformationMatrix.Transform(new PdfPoint(X, Y));
+            operationContext.CurrentPosition = point;
+            operationContext.CurrentSubpath.MoveTo(point.X, point.Y);
         }
 
         /// <inheritdoc />

src/UglyToad.PdfPig/Graphics/Operations/PathConstruction/CloseSubpath.cs

@@ -29,7 +29,7 @@
         /// <inheritdoc />
         public void Run(IOperationContext operationContext)
         {
-            operationContext.CurrentSubpath?.ClosePath();
+            operationContext.CurrentPosition = operationContext.CloseSubpath();
         }
 
         /// <inheritdoc />

src/UglyToad.PdfPig/Graphics/PdfPath.cs

@@ -45,7 +45,7 @@
         /// <summary>
         /// Thickness in user space units of path to be stroked.
         /// </summary>
-        public double LineWidth { get; set; } = double.NaN;
+        public decimal LineWidth { get; set; }
 
         /// <summary>
         /// The pattern to be used for stroked lines.