Corrected the marshalling. Fixes #333

binding/Binding/SKPixmap.cs

@@ -118,7 +118,8 @@ namespace SkiaSharp
 
 		public bool ReadPixels (SKImageInfo dstInfo, IntPtr dstPixels, int dstRowBytes, int srcX, int srcY)
 		{
-			return SkiaApi.sk_pixmap_read_pixels (Handle, ref dstInfo, dstPixels, (IntPtr)dstRowBytes, srcX, srcY);
+			var cinfo = SKImageInfoNative.FromManaged (ref dstInfo);
+			return SkiaApi.sk_pixmap_read_pixels (Handle, ref cinfo, dstPixels, (IntPtr)dstRowBytes, srcX, srcY);
 		}
 
 		public bool ReadPixels (SKImageInfo dstInfo, IntPtr dstPixels, int dstRowBytes)

binding/Binding/SkiaApi.cs

@@ -1384,7 +1384,7 @@ namespace SkiaSharp
 		public extern static bool sk_pixmap_encode_image(sk_wstream_t dst, sk_pixmap_t src, SKEncodedImageFormat encoder, int quality);
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
 		[return: MarshalAs(UnmanagedType.I1)]
-		public extern static bool sk_pixmap_read_pixels(sk_pixmap_t cpixmap, ref SKImageInfo dstInfo, IntPtr dstPixels, IntPtr dstRowBytes, int srcX, int srcY);
+		public extern static bool sk_pixmap_read_pixels(sk_pixmap_t cpixmap, ref SKImageInfoNative dstInfo, IntPtr dstPixels, IntPtr dstRowBytes, int srcX, int srcY);
 
 		// Mask
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]

tests/Tests/SKPixmapTests.cs

@@ -0,0 +1,46 @@
+using System.Runtime.InteropServices;
+using NUnit.Framework;
+
+namespace SkiaSharp.Tests
+{
+	public class SKPixmapTest : SKTest
+	{
+		[Test]
+		public void ReadPixelSucceeds()
+		{
+			var info = new SKImageInfo(10, 10);
+
+			var ptr1 = Marshal.AllocCoTaskMem(info.BytesSize);
+			var pix1 = new SKPixmap(info, ptr1);
+
+			var ptr2 = Marshal.AllocCoTaskMem(info.BytesSize);
+
+			var result = pix1.ReadPixels(info, ptr2, info.RowBytes);
+
+			Assert.True(result);
+		}
+
+		[Test]
+		public void ReadPixelCopiesData()
+		{
+			var info = new SKImageInfo(10, 10);
+
+			using (var bmp1 = new SKBitmap(info))
+			using (var pix1 = bmp1.PeekPixels())
+			using (var bmp2 = new SKBitmap(info))
+			using (var pix2 = bmp2.PeekPixels())
+			{
+				bmp1.Erase(SKColors.Blue);
+				bmp1.Erase(SKColors.Green);
+
+				Assert.AreNotEqual(Marshal.ReadInt64(pix1.GetPixels()), Marshal.ReadInt64(pix2.GetPixels()));
+
+				var result = pix1.ReadPixels(pix2);
+
+				Assert.True(result);
+
+				Assert.AreEqual(Marshal.ReadInt64(pix1.GetPixels()), Marshal.ReadInt64(pix2.GetPixels()));
+			}
+		}
+	}
+}