From 07138c4ff8a0e3d857f96885a0b422e5c65db255 Mon Sep 17 00:00:00 2001
From: Ynse Hoornenborg <github@ynse.nl>
Date: Tue, 23 Apr 2024 18:27:12 +0200
Subject: [PATCH] Use Tile Decoder interface

---
 src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs |  4 +-
 .../Formats/Heif/Av1/IAv1TileDecoder.cs       | 55 +++++++++++++++++++
 .../Heif/Av1/OpenBitstreamUnit/ObuReader.cs   | 12 ++--
 3 files changed, 63 insertions(+), 8 deletions(-)
 create mode 100644 src/ImageSharp/Formats/Heif/Av1/IAv1TileDecoder.cs

diff --git a/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs b/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs
index 884169738..edd4940bf 100644
--- a/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/Av1Decoder.cs
@@ -32,12 +32,12 @@ internal class Av1Decoder : IAv1TileDecoder
         ObuReader.Read(ref reader, buffer.Length, this, false);
     }
 
-    public void DecodeTile(ref Av1BitStreamReader reader, int tileNum)
+    public void DecodeTile(int tileNum)
     {
         // TODO: Implement
     }
 
-    public void FinishDecodeTiles(ref Av1BitStreamReader reader, bool doCdef, bool doLoopRestoration)
+    public void FinishDecodeTiles(bool doCdef, bool doLoopRestoration)
     {
         // TODO: Implement
     }
diff --git a/src/ImageSharp/Formats/Heif/Av1/IAv1TileDecoder.cs b/src/ImageSharp/Formats/Heif/Av1/IAv1TileDecoder.cs
new file mode 100644
index 000000000..345cd29fe
--- /dev/null
+++ b/src/ImageSharp/Formats/Heif/Av1/IAv1TileDecoder.cs
@@ -0,0 +1,55 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+using SixLabors.ImageSharp.Formats.Heif.Av1.OpenBitstreamUnit;
+
+namespace SixLabors.ImageSharp.Formats.Heif.Av1;
+
+/// <summary>
+/// Interface for decoding of image tiles.
+/// </summary>
+internal interface IAv1TileDecoder
+{
+    /// <summary>
+    /// Gets or sets a value indicating whether a sequence header has been read.
+    /// </summary>
+    bool SequenceHeaderDone { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to show the existing frame.
+    /// </summary>
+    bool ShowExistingFrame { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether a FrameHeader has just been read.
+    /// </summary>
+    bool SeenFrameHeader { get; set; }
+
+    /// <summary>
+    /// Gets Information about the frame.
+    /// </summary>
+    ObuFrameHeader FrameInfo { get; }
+
+    /// <summary>
+    /// Gets Information about the sequence of frames.
+    /// </summary>
+    ObuSequenceHeader SequenceHeader { get; }
+
+    /// <summary>
+    /// Gets information required to decode the tiles of a frame.
+    /// </summary>
+    ObuTileInfo TileInfo { get; }
+
+    /// <summary>
+    /// Decode a single tile.
+    /// </summary>
+    /// <param name="tileNum">The index of the tile that is to be decoded.</param>
+    void DecodeTile(int tileNum);
+
+    /// <summary>
+    /// Finshed decoding all tiles of a frame.
+    /// </summary>
+    /// <param name="doCdef">Apply the CDF filter.</param>
+    /// <param name="doLoopRestoration">Apply the loop filters.</param>
+    void FinishDecodeTiles(bool doCdef, bool doLoopRestoration);
+}
diff --git a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs
index 6afd89a24..e0066e7c1 100644
--- a/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/OpenBitstreamUnit/ObuReader.cs
@@ -10,7 +10,7 @@ internal class ObuReader
     /// <summary>
     /// Decode all OBU's in a frame.
     /// </summary>
-    public static void Read(ref Av1BitStreamReader reader, int dataSize, Av1Decoder decoder, bool isAnnexB)
+    public static void Read(ref Av1BitStreamReader reader, int dataSize, IAv1TileDecoder decoder, bool isAnnexB)
     {
         bool frameDecodingFinished = false;
         while (!frameDecodingFinished)
@@ -629,7 +629,7 @@ internal class ObuReader
         return tileInfo;
     }
 
-    private static void ReadUncompressedFrameHeader(ref Av1BitStreamReader reader, Av1Decoder decoder, ObuHeader header, int planesCount)
+    private static void ReadUncompressedFrameHeader(ref Av1BitStreamReader reader, IAv1TileDecoder decoder, ObuHeader header, int planesCount)
     {
         ObuSequenceHeader sequenceHeader = decoder.SequenceHeader;
         ObuFrameHeader frameInfo = decoder.FrameInfo;
@@ -915,7 +915,7 @@ internal class ObuReader
         }
     }
 
-    private static void ReadFrameHeader(ref Av1BitStreamReader reader, Av1Decoder decoder, ObuHeader header, bool trailingBit)
+    private static void ReadFrameHeader(ref Av1BitStreamReader reader, IAv1TileDecoder decoder, ObuHeader header, bool trailingBit)
     {
         ObuSequenceHeader sequenceHeader = decoder.SequenceHeader;
         ObuFrameHeader frameInfo = decoder.FrameInfo;
@@ -934,7 +934,7 @@ internal class ObuReader
         header.PayloadSize -= headerBytes;
     }
 
-    private static void ReadTileGroup(ref Av1BitStreamReader reader, Av1Decoder decoder, ObuHeader header, out bool isLastTileGroup)
+    private static void ReadTileGroup(ref Av1BitStreamReader reader, IAv1TileDecoder decoder, ObuHeader header, out bool isLastTileGroup)
     {
         ObuSequenceHeader sequenceHeader = decoder.SequenceHeader;
         ObuFrameHeader frameInfo = decoder.FrameInfo;
@@ -991,7 +991,7 @@ internal class ObuReader
             }
 
             // TODO: Pass more info to the decoder.
-            decoder.DecodeTile(ref reader, tileNum);
+            decoder.DecodeTile(tileNum);
         }
 
         if (tileGroupEnd != tileCount - 1)
@@ -999,7 +999,7 @@ internal class ObuReader
             return;
         }
 
-        decoder.FinishDecodeTiles(ref reader, doCdef, doLoopRestoration);
+        decoder.FinishDecodeTiles(doCdef, doLoopRestoration);
     }
 
     private static int ReadDeltaQ(ref Av1BitStreamReader reader)