项目结构调整

Others/WpfAnimatedGif/Decoding/GifPlainTextExtension.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+
+namespace WpfAnimatedGif.Decoding
+{
+    // label 0x01
+    internal class GifPlainTextExtension : GifExtension
+    {
+        internal const int ExtensionLabel = 0x01;
+
+        public int BlockSize { get; private set; }
+        public int Left { get; private set; }
+        public int Top { get; private set; }
+        public int Width { get; private set; }
+        public int Height { get; private set; }
+        public int CellWidth { get; private set; }
+        public int CellHeight { get; private set; }
+        public int ForegroundColorIndex { get; private set; }
+        public int BackgroundColorIndex { get; private set; }
+        public string Text { get; private set; }
+
+        public IList<GifExtension> Extensions { get; private set; }
+
+        private GifPlainTextExtension()
+        {
+        }
+
+        internal override GifBlockKind Kind
+        {
+            get { return GifBlockKind.GraphicRendering; }
+        }
+
+        internal static GifPlainTextExtension ReadPlainText(Stream stream, IEnumerable<GifExtension> controlExtensions, bool metadataOnly)
+        {
+            var plainText = new GifPlainTextExtension();
+            plainText.Read(stream, controlExtensions, metadataOnly);
+            return plainText;
+        }
+
+        private void Read(Stream stream, IEnumerable<GifExtension> controlExtensions, bool metadataOnly)
+        {
+            // Note: at this point, the label (0x01) has already been read
+
+            byte[] bytes = new byte[13];
+            stream.ReadAll(bytes,0, bytes.Length);
+
+            BlockSize = bytes[0];
+            if (BlockSize != 12)
+                throw GifHelpers.InvalidBlockSizeException("Plain Text Extension", 12, BlockSize);
+
+            Left = BitConverter.ToUInt16(bytes, 1);
+            Top = BitConverter.ToUInt16(bytes, 3);
+            Width = BitConverter.ToUInt16(bytes, 5);
+            Height = BitConverter.ToUInt16(bytes, 7);
+            CellWidth = bytes[9];
+            CellHeight = bytes[10];
+            ForegroundColorIndex = bytes[11];
+            BackgroundColorIndex = bytes[12];
+
+            var dataBytes = GifHelpers.ReadDataBlocks(stream, metadataOnly);
+            Text = Encoding.ASCII.GetString(dataBytes);
+            Extensions = controlExtensions.ToList().AsReadOnly();
+        }
+    }
+}