Add helpers which return raw SpiroSegment arrays

Add ToString methods on types

src/SpiroNet/Spiro.cs

@@ -72,6 +72,55 @@ namespace SpiroNet
             TaggedSpiroCPsToBezier0(spiros, bc);
         }
 
+        /// <summary>
+        /// Convert a set of spiro control points into a set of bézier curves.
+        /// 
+        /// As it does so it will call the appropriate routine in your bézier context with this information 
+        /// – this should allow you to create your own internal representation of those curves.
+        /// 
+        /// Open contours do not need to start with '{', nor to end with '}'.
+        /// 
+        /// Close contours do not need to end with 'z'.
+        /// 
+        /// This function is kept for backwards compatibility for older programs. 
+        /// Please use the function that return success/failure replies when done.	
+        /// </summary>
+        /// <param name="spiros">An array of input spiros.</param>
+        /// <param name="n">The number of elements in the spiros array.</param>
+        /// <param name="isClosed">Whether this describes a closed (True) or open (False) contour.</param>
+        /// <param name="bc">A bézier results output context.</param>
+        /// <returns>SpiroSegment array or null on failure.</returns>
+        /// <example>
+        /// var points = new SpiroControlPoint[4];
+        /// points[0].X = -100; points[0].Y = 0; points[0].Type = SpiroPointType.G4;
+        /// points[1].X = 0; points[1].Y = 100; points[1].Type = SpiroPointType.G4;
+        /// points[2].X = 100; points[2].Y = 0; points[2].Type = SpiroPointType.G4;
+        /// points[3].X = 0; points[3].Y = -100; points[3].Type = SpiroPointType.G4;
+        /// var bc = new PathBezierContext();
+        /// var success = Spiro.SpiroCPsToBezier0(points, 4, true, bc);
+        /// Console.WriteLine(bc);
+        /// Console.WriteLine("Success: {0} ", success);
+        /// </example>
+        public static SpiroSegment[]? SpiroCPsToSegments(SpiroControlPoint[] spiros, int n, bool isClosed)
+        {
+            if (n <= 0)
+                return null;
+            if (isClosed)
+                return SpiroImpl.run_spiro(spiros, n);
+            else
+            {
+                SpiroPointType oldty_start = spiros[0].Type;
+                SpiroPointType oldty_end = spiros[n - 1].Type;
+                spiros[0].Type = SpiroPointType.OpenContour;
+                spiros[n - 1].Type = SpiroPointType.EndOpenContour;
+                SpiroSegment[]? s;
+                s = SpiroImpl.run_spiro(spiros, n);
+                spiros[n - 1].Type = oldty_end;
+                spiros[0].Type = oldty_start;
+                return s;
+            }
+        }
+
         /// <summary>
         /// Convert a set of spiro control points into a set of bézier curves.
         /// 
@@ -103,23 +152,7 @@ namespace SpiroNet
         /// </example>
         public static bool SpiroCPsToBezier0(SpiroControlPoint[] spiros, int n, bool isClosed, IBezierContext bc)
         {
-            SpiroSegment[]? s;
-
-            if (n <= 0)
-                return false;
-            if (isClosed)
-                s = SpiroImpl.run_spiro(spiros, n);
-            else
-            {
-                SpiroPointType oldty_start = spiros[0].Type;
-                SpiroPointType oldty_end = spiros[n - 1].Type;
-                spiros[0].Type = SpiroPointType.OpenContour;
-                spiros[n - 1].Type = SpiroPointType.EndOpenContour;
-                s = SpiroImpl.run_spiro(spiros, n);
-                spiros[n - 1].Type = oldty_end;
-                spiros[0].Type = oldty_start;
-            }
-
+            SpiroSegment[]? s = SpiroCPsToSegments(spiros, n, isClosed);
             if (s != null)
             {
                 SpiroImpl.spiro_to_bpath(s, n, bc);
@@ -129,6 +162,69 @@ namespace SpiroNet
             return false; // spiro did not converge or encountered non-finite values
         }
 
+        /// <summary>
+        /// Convert a tagged set of spiro control points into a set of bézier curves.
+        /// 
+        /// As it does so it will call the appropriate routine in your bézier context with this information 
+        /// – this should allow you to create your own internal representation of those curves.
+        /// 
+        /// The spiros array should indicate it's own end.
+        /// 
+        /// Open contours must have the ty field of the first cp set to '{' and have the ty field of the last cp set to '}'.
+        /// 
+        /// Closed contours must have an extra cp at the end whose ty is 'z' the x and y values of this extra cp are ignored.
+        /// </summary>
+        /// <param name="spiros">An array of input spiros.</param>
+        /// <param name="bc">A bézier results output context.</param>
+        /// <returns>SpiroSegment array or null on failure.</returns>
+        /// <example>
+        /// var points = new SpiroControlPoint[5];
+        /// points[0].X = -100; points[0].Y = 0; points[0].Type = SpiroPointType.G4;
+        /// points[1].X = 0; points[1].Y = 100; points[1].Type = SpiroPointType.G4;
+        /// points[2].X = 100; points[2].Y = 0; points[2].Type = SpiroPointType.G4;
+        /// points[3].X = 0; points[3].Y = -100; points[3].Type = SpiroPointType.G4;
+        /// points[4].X = 0; points[4].Y = 0; points[4].Type = SpiroPointType.End;
+        /// var bc = new PathBezierContext();
+        /// var success = Spiro.TaggedSpiroCPsToBezier0(points, bc);
+        /// Console.WriteLine(bc);
+        /// Console.WriteLine("Success: {0} ", success);
+        /// 
+        /// var points = new SpiroControlPoint[5];
+        /// points[0].X = -100; points[0].Y = 0; points[0].Type = SpiroPointType.G4;
+        /// points[1].X = 0; points[1].Y = 100; points[1].Type = SpiroPointType.G4;
+        /// points[2].X = 100; points[2].Y = 0; points[2].Type = SpiroPointType.G4;
+        /// points[3].X = 0; points[3].Y = -100; points[3].Type = SpiroPointType.G4;
+        /// points[4].X = 0; points[4].Y = 0; points[4].Type = SpiroPointType.End;
+        /// var bc = new PathBezierContext();
+        /// var success = Spiro.TaggedSpiroCPsToBezier0(points, bc);
+        /// Console.WriteLine(bc);
+        /// Console.WriteLine("Success: {0} ", success);
+        /// </example>
+        public static SpiroSegment[]? TaggedSpiroCPsToSegments(SpiroControlPoint[] spiros)
+        {
+            if(spiros.Length == 0) return null;
+            int n = 0;
+            while (true)
+            {
+                if (spiros[n].Type == SpiroPointType.End || spiros[n].Type == SpiroPointType.EndOpenContour)
+                    break;
+
+                // invalid input
+                if (n >= spiros.Length)
+                    return null;
+
+                ++n;
+            }
+
+            if (spiros[n].Type == SpiroPointType.EndOpenContour)
+                ++n;
+
+            if (n <= 0)
+                return null; // invalid input
+
+            return SpiroImpl.run_spiro(spiros, n);
+        }
+
         /// <summary>
         /// Convert a tagged set of spiro control points into a set of bézier curves.
         /// 
@@ -169,33 +265,10 @@ namespace SpiroNet
         /// </example>
         public static bool TaggedSpiroCPsToBezier0(SpiroControlPoint[] spiros, IBezierContext bc)
         {
-            SpiroSegment[]? s;
-            int n;
-
-            n = 0;
-            while (true)
-            {
-                if (spiros[n].Type == SpiroPointType.End || spiros[n].Type == SpiroPointType.EndOpenContour)
-                    break;
-
-                // invalid input
-                if (n >= spiros.Length)
-                    return false;
-
-                ++n;
-            }
-
-            if (spiros[n].Type == SpiroPointType.EndOpenContour)
-                ++n;
-
-            if (n <= 0)
-                return false; // invalid input
-
-            s = SpiroImpl.run_spiro(spiros, n);
-
+            var s = TaggedSpiroCPsToSegments(spiros);
             if (s != null)
             {
-                SpiroImpl.spiro_to_bpath(s, n, bc);
+                SpiroImpl.spiro_to_bpath(s, s.Length-1, bc);
                 return true; // success
             }
 

src/SpiroNet/SpiroControlPoint.cs

@@ -41,5 +41,10 @@ namespace SpiroNet
         /// Spiro code point Type.
         /// </summary>
         public SpiroPointType Type;
+
+        public override string ToString()
+        {
+            return X.ToString() + ", " + Y.ToString() + ", " + Type.ToString();
+        }
     }
 }

src/SpiroNet/SpiroSegment.cs

@@ -68,5 +68,11 @@ namespace SpiroNet
         /// Unused.
         /// </summary>
         public double l;
+
+        public override string ToString()
+        {
+            return X.ToString() + ", " + Y.ToString() + ", " + Type.ToString() + " (" +
+                seg_th.ToString() + ")";
+        }
     }
 }