Added SKPathMeasure to the C# API

binding/Binding/Binding.projitems

@@ -21,6 +21,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)SKDocument.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SKPathEffect.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)GRContext.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)SKPathMeasure.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SKSurface.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SKCanvas.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SKShader.cs" />

binding/Binding/SKPathMeasure.cs

@@ -0,0 +1,98 @@
+//
+// Bindings for SKPathMeasure
+//
+// Author:
+//   Matthew Leibowitz
+//
+// Copyright 2016 Xamarin Inc
+//
+using System;
+
+namespace SkiaSharp
+{
+	public class SKPathMeasure : SKObject
+	{
+		[Flags]
+		public enum MatrixFlags {
+			GetPosition = 0x01,
+			GetTangent = 0x02,
+			GetPositionAndTangent = GetPosition | GetTangent,
+		}
+
+		[Preserve]
+		internal SKPathMeasure (IntPtr handle, bool owns)
+			: base (handle, owns)
+		{
+		}
+
+		public SKPathMeasure ()
+			: this (SkiaApi.sk_pathmeasure_new (), true)
+		{
+			if (Handle == IntPtr.Zero) {
+				throw new InvalidOperationException ("Unable to create a new SKPathMeasure instance.");
+			}
+		}
+
+		public SKPathMeasure (SKPath path, bool forceClosed = false, float resScale = 1)
+			: this (SkiaApi.sk_pathmeasure_new_with_path (path == null ? IntPtr.Zero : path.Handle, forceClosed, resScale), true)
+		{
+			if (Handle == IntPtr.Zero) {
+				throw new InvalidOperationException ("Unable to create a new SKPathMeasure instance.");
+			}
+		}
+		
+		protected override void Dispose (bool disposing)
+		{
+			if (Handle != IntPtr.Zero && OwnsHandle) {
+				SkiaApi.sk_pathmeasure_destroy (Handle);
+			}
+
+			base.Dispose (disposing);
+		}
+
+		public float Length {
+			get {
+				return SkiaApi.sk_pathmeasure_get_length (Handle);
+			}
+		}
+
+		public bool IsClosed {
+			get {
+				return SkiaApi.sk_pathmeasure_is_closed (Handle);
+			}
+		}
+
+		public void SetPath (SKPath path, bool forceClosed)
+		{
+			SkiaApi.sk_pathmeasure_set_path (Handle, path == null ? IntPtr.Zero : path.Handle, forceClosed);
+		}
+
+		public bool GetPositionAndTangent (float distance, out SKPoint position, out SKPoint tangent)
+		{
+			return SkiaApi.sk_pathmeasure_get_pos_tan (Handle, distance, out position, out tangent);
+		}
+
+		public bool GetPosition (float distance, out SKPoint position)
+		{
+			return SkiaApi.sk_pathmeasure_get_pos_tan (Handle, distance, out position, IntPtr.Zero);
+		}
+
+		public bool GetTangent (float distance, out SKPoint tangent)
+		{
+			return SkiaApi.sk_pathmeasure_get_pos_tan (Handle, distance, IntPtr.Zero, out tangent);
+		}
+
+		public bool GetMatrix (float distance, out SKMatrix matrix, MatrixFlags flags)
+		{
+			return SkiaApi.sk_pathmeasure_get_matrix (Handle, distance, out matrix, flags);
+		}
+
+		public bool GetSegment (float start, float stop, SKPath dst, bool startWithMoveTo)
+		{
+			if (dst == null)
+				throw new ArgumentNullException (nameof (dst));
+			return SkiaApi.sk_pathmeasure_get_segment (Handle, start, stop, dst.Handle, startWithMoveTo);
+		}
+	}
+}
+

binding/Binding/SkiaApi.cs

@@ -43,6 +43,7 @@ using sk_document_t = System.IntPtr;
 using sk_colorspace_t = System.IntPtr;
 using sk_path_iterator_t = System.IntPtr;
 using sk_path_effect_t = System.IntPtr;
+using sk_pathmeasure_t = System.IntPtr;
 using sk_pixelref_factory_t = System.IntPtr;
 using sk_colortable_t = System.IntPtr;
 using gr_context_t = System.IntPtr;
@@ -504,6 +505,38 @@ namespace SkiaSharp
 		[DllImport (SKIA, CallingConvention = CallingConvention.Cdecl)]
 		public extern static int sk_path_convert_conic_to_quads(ref SKPoint p0, ref SKPoint p1, ref SKPoint p2, float w, [Out] SKPoint[] pts, int pow2);
 
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static sk_pathmeasure_t sk_pathmeasure_new();
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static sk_pathmeasure_t sk_pathmeasure_new_with_path(sk_path_t path, bool forceClosed, float resScale);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static void sk_pathmeasure_destroy(sk_pathmeasure_t pathMeasure);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static void sk_pathmeasure_set_path(sk_pathmeasure_t pathMeasure, sk_path_t path, bool forceClosed);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static float sk_pathmeasure_get_length(sk_pathmeasure_t pathMeasure);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_get_pos_tan(sk_pathmeasure_t pathMeasure, float distance, out SKPoint position, out SKPoint tangent);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_get_pos_tan(sk_pathmeasure_t pathMeasure, float distance, IntPtr positionZero, out SKPoint tangent);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_get_pos_tan(sk_pathmeasure_t pathMeasure, float distance, out SKPoint position, IntPtr tangentZero);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_get_matrix(sk_pathmeasure_t pathMeasure, float distance, out SKMatrix matrix, SKPathMeasure.MatrixFlags flags);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_get_segment(sk_pathmeasure_t pathMeasure, float start, float stop, sk_path_t dst, bool startWithMoveTo);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_is_closed(sk_pathmeasure_t pathMeasure);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_pathmeasure_next_contour(sk_pathmeasure_t pathMeasure);
+
 		// path ops
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
 		[return: MarshalAs(UnmanagedType.I1)]

externals/skia

@@ -1 +1 @@
-Subproject commit 801831b60769f40f1fc606feb9ad624c7d12d9e3
+Subproject commit b1d9ddd8bacc8464f93583c314799d910b056ab3

samples/SkiaSharpSample.Shared/Samples/PathMeasureSample.cs

@@ -0,0 +1,61 @@
+using SkiaSharp;
+
+namespace SkiaSharpSample.Samples
+{
+	[Preserve(AllMembers = true)]
+	public class PathMeasureSample : SampleBase
+	{
+		[Preserve]
+		public PathMeasureSample()
+		{
+		}
+
+		public override string Title => "Path Measure";
+
+		public override SampleCategories Category => SampleCategories.Paths;
+
+		protected override void OnDrawSample(SKCanvas canvas, int width, int height)
+		{
+			canvas.Clear(SKColors.White);
+
+			using (SKPaint paint = new SKPaint())
+			using (SKPath path = new SKPath())
+			{
+				paint.Style = SKPaintStyle.Stroke;
+				paint.StrokeWidth = 10;
+				paint.IsAntialias = true;
+				paint.StrokeCap = SKStrokeCap.Round;
+				paint.StrokeJoin = SKStrokeJoin.Round;
+
+				path.MoveTo(20, 20);
+				path.LineTo(400, 50);
+				path.LineTo(80, 100);
+				path.LineTo(300, 150);
+
+				paint.Color = SampleMedia.Colors.XamarinDarkBlue;
+				canvas.DrawPath(path, paint);
+
+				using (var measure = new SKPathMeasure(path, false))
+				using (var dst = new SKPath())
+				{
+					var length = measure.Length;
+
+					dst.Reset();
+					measure.GetSegment(length * 0.05f, length * 0.2f, dst, true);
+					paint.Color = SampleMedia.Colors.XamarinPurple;
+					canvas.DrawPath(dst, paint);
+
+					dst.Reset();
+					measure.GetSegment(length * 0.2f, length * 0.8f, dst, true);
+					paint.Color = SampleMedia.Colors.XamarinGreen;
+					canvas.DrawPath(dst, paint);
+
+					dst.Reset();
+					measure.GetSegment(length * 0.8f, length * 0.95f, dst, true);
+					paint.Color = SampleMedia.Colors.XamarinLightBlue;
+					canvas.DrawPath(dst, paint);
+				}
+			}
+		}
+	}
+}

samples/SkiaSharpSample.Shared/SkiaSharpSample.Shared.projitems

@@ -18,6 +18,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)SampleMedia.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\BitmapSubsetDecoderSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\ManipulatedBitmapShaderSample.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Samples\PathMeasureSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\PathConicToQuadsSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\XamagonSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\TextSample.cs" />

tests/Tests/SKPathTest.cs

@@ -211,5 +211,28 @@ namespace SkiaSharp.Tests
 				Assert.AreEqual (14.185303f, tightBounds.Bottom, EPSILON);
 			}
 		}
+
+		[Test]
+		public void MeasuringSegementsWorks ()
+		{
+			const float EPSILON = 0.000001f;
+
+			using (SKPath path = new SKPath ())
+			{
+				path.MoveTo (10f, 10f);
+				path.LineTo (110f, 10f);
+
+				var measure = new SKPathMeasure (path);
+
+				Assert.AreEqual (100f, measure.Length, EPSILON);
+
+				var segment = new SKPath ();
+				var result = measure.GetSegment (20, 50, segment, true);
+				Assert.IsTrue (result);
+				Assert.AreEqual (2, segment.PointCount);
+				Assert.AreEqual (new SKPoint (30, 10), segment.Points [0]);
+				Assert.AreEqual (new SKPoint (60, 10), segment.Points [1]);
+			}
+		}
 	}
 }