Png chunk reader codec bitmap

binding/Binding/SKBitmap.cs

@@ -37,8 +37,6 @@ public static SKFilterQuality ToFilterQuality (this SKBitmapResizeMethod method)
 	}
 
 	// TODO: keep in mind SKBitmap may be going away (according to Google)
-	// TODO: `ComputeIsOpaque` may be useful
-	// TODO: `GenerationID` may be useful
 	// TODO: `GetAddr` and `GetPixel` are confusing
 
 	public unsafe class SKBitmap : SKObject, ISKSkipObjectRegistration
@@ -115,6 +113,47 @@ protected override void Dispose (bool disposing) =>
 		protected override void DisposeNative () =>
 			SkiaApi.sk_bitmap_destructor (Handle);
 
+		// Other
+
+		public bool SetInfo (SKImageInfo info) =>
+			SetInfo (info, 0);
+
+		public bool SetInfo (SKImageInfo info, int rowBytes)
+		{
+			var cinfo = SKImageInfoNative.FromManaged (ref info);
+			return SkiaApi.sk_bitmap_set_info (Handle, &cinfo, (IntPtr)rowBytes);
+		}
+
+		public bool ComputeIsOpaque () =>
+			SkiaApi.sk_bitmap_compute_is_opaque (Handle);
+
+		// AllocPixels
+
+		public void AllocPixels (SKImageInfo info) =>
+			AllocPixels (info, info.RowBytes);
+
+		public void AllocPixels (SKImageInfo info, int rowBytes)
+		{
+			if (!TryAllocPixels (info, rowBytes)) {
+				SKImageInfo i = Info;
+				throw new OutOfMemoryException ("SkBitmap::tryAllocPixels failed "
+					+ "ColorType:" + i.ColorType + "AlphaType:" + i.AlphaType +
+					"[w:" + i.Width + " h:" + i.Height + "] rb:" + RowBytes
+				);
+			}
+		}
+
+		public void AllocPixels (SKImageInfo info, SKBitmapAllocFlags flags)
+		{
+			if (!TryAllocPixels (info, flags)) {
+				SKImageInfo i = Info;
+				throw new OutOfMemoryException ("SkBitmap::tryAllocPixels failed "
+					+ "ColorType:" + i.ColorType + "AlphaType:" + i.AlphaType +
+					"[w:" + i.Width + " h:" + i.Height + "] rb:" + RowBytes
+				);
+			}
+		}
+
 		// TryAllocPixels
 
 		public bool TryAllocPixels (SKImageInfo info)
@@ -361,6 +400,9 @@ public int ByteCount {
 			get { return (int)SkiaApi.sk_bitmap_get_byte_count (Handle); }
 		}
 
+		public uint GenerationId =>
+			(uint)SkiaApi.sk_bitmap_get_generation_id (Handle);
+
 		// *Pixels*
 
 		public IntPtr GetPixels () =>
@@ -401,6 +443,14 @@ public void SetColorTable (SKColorTable ct)
 
 		// more properties
 
+		public SKPixmap Pixmap {
+			get {
+				var pixmap = new SKPixmap (SkiaApi.sk_bitmap_get_pixmap (Handle), false); // pixmap is owned by this
+				pixmap.pixelSource = this;
+				return pixmap;
+			}
+		}
+
 		public byte[] Bytes {
 			get {
 				var array = GetPixelSpan ().ToArray ();
@@ -723,6 +773,29 @@ public bool InstallPixels (SKImageInfo info, IntPtr pixels, int rowBytes, SKBitm
 			return SkiaApi.sk_bitmap_install_pixels (Handle, &cinfo, (void*)pixels, (IntPtr)rowBytes, proxy, (void*)ctx);
 		}
 
+		public bool ReadPixels (SKImageInfo info, IntPtr dstPixels, int rowBytes, int x, int y)
+		{
+			if (GetPixels () == IntPtr.Zero)
+				return false;
+			return Pixmap.ReadPixels (info, dstPixels, rowBytes, x, y);
+		}
+
+		public bool ReadPixels (SKPixmap dstPixmap) =>
+			ReadPixels (dstPixmap, 0, 0);
+
+		public bool ReadPixels (SKPixmap dstPixmap, int x, int y)
+		{
+			if (GetPixels () == IntPtr.Zero)
+				return false;
+			return Pixmap.ReadPixels (dstPixmap.Info, dstPixmap.GetPixels (), dstPixmap.RowBytes, x, y);
+		}
+
+		public bool WritePixels (SKPixmap pixmap) =>
+			WritePixels (pixmap, 0, 0);
+
+		public bool WritePixels (SKPixmap dstPixmap, int x, int y) =>
+			SkiaApi.sk_bitmap_write_pixels_at_location (Handle, dstPixmap.Handle, x, y);
+
 		public bool InstallPixels (SKPixmap pixmap)
 		{
 			return SkiaApi.sk_bitmap_install_pixels_with_pixmap (Handle, pixmap.Handle);
@@ -842,6 +915,9 @@ public static SKBitmap FromImage (SKImage image)
 			return bmp;
 		}
 
+		public SKImage ToImage () =>
+			SKImage.FromBitmap (this);
+
 		// Encode
 
 		public SKData Encode (SKEncodedImageFormat format, int quality)

binding/Binding/SKCodec.cs

@@ -4,7 +4,6 @@
 
 namespace SkiaSharp
 {
-	// TODO: `Create(...)` should have overloads that accept a SKPngChunkReader
 	// TODO: missing the `QueryYuv8` and `GetYuv8Planes` members
 
 	public unsafe class SKCodec : SKObject, ISKSkipObjectRegistration
@@ -42,6 +41,8 @@ public SKImageInfo Info {
 		public SKEncodedImageFormat EncodedFormat =>
 			SkiaApi.sk_codec_get_encoded_format (Handle);
 
+		public SKSizeI EncodedDimensions => Info.Size;
+
 		public SKSizeI GetScaledDimensions (float desiredScale)
 		{
 			SKSizeI dimensions;
@@ -277,53 +278,72 @@ public bool SkipScanlines (int countLines) =>
 		public int GetOutputScanline (int inputScanline) =>
 			SkiaApi.sk_codec_output_scanline (Handle, inputScanline);
 
-		// create (streams)
+		// create (filename)
 
 		public static SKCodec Create (string filename) =>
-			Create (filename, out var result);
+			Create (filename, null, SKCodecSelectionPolicy.PreferStillImage, out _);
+
+		public static SKCodec Create (string filename, out SKCodecResult result) =>
+			Create (filename, null, SKCodecSelectionPolicy.PreferStillImage, out result);
 
-		public static SKCodec Create (string filename, out SKCodecResult result)
+		public static SKCodec Create (string filename, SKPngChunkReader chunkReader, SKCodecSelectionPolicy selectionPolicy, out SKCodecResult result)
 		{
 			var stream = SKFileStream.OpenStream (filename);
 			if (stream == null) {
 				result = SKCodecResult.InternalError;
 				return null;
 			}
 
-			return Create (stream, out result);
+			return Create (stream, chunkReader, selectionPolicy, out result);
 		}
 
+		// create (Stream)
+
 		public static SKCodec Create (Stream stream) =>
-			Create (stream, out var result);
+			Create (WrapManagedStream (stream), null, SKCodecSelectionPolicy.PreferStillImage, out _);
 
 		public static SKCodec Create (Stream stream, out SKCodecResult result) =>
-			Create (WrapManagedStream (stream), out result);
+			Create (WrapManagedStream (stream), null, SKCodecSelectionPolicy.PreferStillImage, out result);
+
+		public static SKCodec Create (Stream stream, SKPngChunkReader chunkReader, SKCodecSelectionPolicy selectionPolicy, out SKCodecResult result) =>
+			Create (WrapManagedStream (stream), chunkReader, selectionPolicy, out result);
+
+		// create (SKStream)
 
 		public static SKCodec Create (SKStream stream) =>
-			Create (stream, out var result);
+			Create (stream, null, SKCodecSelectionPolicy.PreferStillImage, out _);
+
+		public static SKCodec Create (SKStream stream, out SKCodecResult result) =>
+			Create (stream, null, SKCodecSelectionPolicy.PreferStillImage, out result);
 
-		public static SKCodec Create (SKStream stream, out SKCodecResult result)
+		public static SKCodec Create (SKStream stream, SKPngChunkReader chunkReader, SKCodecSelectionPolicy selectionPolicy, out SKCodecResult result)
 		{
 			if (stream == null)
 				throw new ArgumentNullException (nameof (stream));
 			if (stream is SKFileStream filestream && !filestream.IsValid)
-				throw new ArgumentException ("File stream was not valid.", nameof(stream));
+				throw new ArgumentException ("File stream was not valid.", nameof (stream));
 
 			fixed (SKCodecResult* r = &result) {
-				var codec = GetObject (SkiaApi.sk_codec_new_from_stream (stream.Handle, r));
+				var codec = GetObject (SkiaApi.sk_codec_new_from_stream_with_pngchunkreader_and_selection_policy (stream.Handle, r, chunkReader?.Handle ?? IntPtr.Zero, selectionPolicy));
 				stream.RevokeOwnership (codec);
+				Referenced (codec, chunkReader);
 				return codec;
 			}
 		}
 
 		// create (data)
 
-		public static SKCodec Create (SKData data)
+		public static SKCodec Create (SKData data) =>
+			Create (data, null);
+
+		public static SKCodec Create (SKData data, SKPngChunkReader chunkReader)
 		{
 			if (data == null)
 				throw new ArgumentNullException (nameof (data));
 
-			return GetObject (SkiaApi.sk_codec_new_from_data (data.Handle));
+			var codec = GetObject (SkiaApi.sk_codec_new_from_data_with_pngchunkreader (data.Handle, chunkReader?.Handle ?? IntPtr.Zero));
+			Referenced (codec, chunkReader);
+			return codec;
 		}
 
 		// utils

binding/Binding/SKObject.cs

@@ -193,7 +193,7 @@ internal static T Owned<T> (T owner, SKObject child)
 			return owner;
 		}
 
-		// indicate that the chile should not be garbage collected while
+		// indicate that the child should not be garbage collected while
 		// the owner still lives
 		internal static T Referenced<T> (T owner, SKObject child)
 			where T : SKObject

binding/Binding/SKPngChunkReader.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Runtime.InteropServices;
+using System.Threading;
+
+namespace SkiaSharp
+{
+	public unsafe abstract class SKPngChunkReader : SKObject, ISKSkipObjectRegistration
+	{
+		private static readonly SKManagedPngChunkReaderDelegates delegates;
+		private readonly IntPtr userData;
+		private int fromNative;
+
+		static SKPngChunkReader ()
+		{
+			delegates = new SKManagedPngChunkReaderDelegates {
+				fReadChunk = ReadChunkInternal,
+				fDestroy = DestroyInternal,
+			};
+
+			SkiaApi.sk_managedpngchunkreader_set_procs (delegates);
+		}
+
+		protected SKPngChunkReader ()
+			: base (IntPtr.Zero, true)
+		{
+			userData = DelegateProxies.CreateUserData (this, true);
+			Handle = SkiaApi.sk_managedpngchunkreader_new ((void*)userData);
+
+			if (Handle == IntPtr.Zero)
+				throw new InvalidOperationException ("Unable to create a new SKPngChunkReader instance.");
+		}
+
+		protected override void DisposeNative ()
+		{
+			if (Interlocked.CompareExchange (ref fromNative, 0, 0) == 0) {
+				SkiaApi.sk_managedpngchunkreader_delete (Handle);
+			}
+		}
+
+		protected abstract bool ReadChunk (string tag, IntPtr data, IntPtr length);
+
+		// impl
+
+		[MonoPInvokeCallback (typeof (SKManagedPngChunkReaderReadChunkProxyDelegate))]
+		private static bool ReadChunkInternal (IntPtr d, void* context, void* tag, void* data, IntPtr length)
+		{
+			var dump = DelegateProxies.GetUserData<SKPngChunkReader> ((IntPtr)context, out _);
+			return dump.ReadChunk (Marshal.PtrToStringAnsi ((IntPtr)tag), (IntPtr)data, length);
+		}
+
+		[MonoPInvokeCallback (typeof (SKManagedPngChunkReaderDestroyProxyDelegate))]
+		private static void DestroyInternal (IntPtr s, void* context)
+		{
+			var id = DelegateProxies.GetUserData<SKPngChunkReader> ((IntPtr)context, out var gch);
+			if (id != null) {
+				Interlocked.Exchange (ref id.fromNative, 1);
+				id.Dispose ();
+			}
+			gch.Free ();
+		}
+	}
+}