public ExtraInformation(byte[] bytes, ref int byteIndex)
{ // Extension Introducer(1 byte)
// 0x21
Introducer = bytes[byteIndex];
byteIndex++;
// Extension Label(1 byte)
// 0xFF
Label = bytes[byteIndex];
byteIndex++;
// Block Size(1 byte)
// 0x0B
BlockSize = bytes[byteIndex];
byteIndex++;
// Application Identifier(8 byte)
ApplicationIdentifier = Encoding.ASCII.GetString(bytes, byteIndex, 8);
byteIndex += 8;
// Application Authentication Code(3 byte)
ApplicationAuthenticationCode = Encoding.ASCII.GetString(bytes, byteIndex, 3);
byteIndex += 3;
Blocks = new List <BytesBlock>();
// Block Size & Application Data List
while (true)
{
// Block Size (1 byte)
var blockSize = bytes[byteIndex];
byteIndex++;
if (blockSize == 0x00)
{
// Block Terminator(1 byte)
break;
}
var block = new BytesBlock();
block.Size = blockSize;
// Application Data(n byte)
block.Bytes = new byte[block.Size];
for (var index = 0; index < block.Bytes.Length; index++)
{
block.Bytes[index] = bytes[byteIndex];
byteIndex++;
}
Blocks.Add(block);
}
}
public ExtraComment(byte[] bytes, ref int byteIndex)
{
// Extension Introducer(1 byte)
// 0x21
Introducer = bytes[byteIndex];
byteIndex++;
// Comment Label(1 byte)
// 0xFE
Label = bytes[byteIndex];
byteIndex++;
Blocks = new List <BytesBlock>();
// Block Size & Comment Data List
while (true)
{
// Block Size(1 byte)
var blockSize = bytes[byteIndex];
byteIndex++;
if (blockSize == 0x00)
{
// Block Terminator(1 byte)
break;
}
var block = new BytesBlock();
block.Size = blockSize;
// Comment Data(n byte)
block.Bytes = new byte[block.Size];
for (var index = 0; index < block.Bytes.Length; index++)
{
block.Bytes[index] = bytes[byteIndex];
byteIndex++;
}
Blocks.Add(block);
}
}
public ExtraText(byte[] bytes, ref int byteIndex)
{ // Extension Introducer(1 byte)
// 0x21
Introducer = bytes[byteIndex];
byteIndex++;
// Plain Text Label(1 byte)
// 0x01
Label = bytes[byteIndex];
byteIndex++;
// Block Size(1 byte)
// 0x0c
BlockSize = bytes[byteIndex];
byteIndex++;
// Text Grid Left Position(2 byte)
// Not supported
byteIndex += 2;
// Text Grid Top Position(2 byte)
// Not supported
byteIndex += 2;
// Text Grid Width(2 byte)
// Not supported
byteIndex += 2;
// Text Grid Height(2 byte)
// Not supported
byteIndex += 2;
// Character Cell Width(1 byte)
// Not supported
byteIndex++;
// Character Cell Height(1 byte)
// Not supported
byteIndex++;
// Text Foreground Color Index(1 byte)
// Not supported
byteIndex++;
// Text Background Color Index(1 byte)
// Not supported
byteIndex++;
Blocks = new List <BytesBlock>();
// Block Size & Plain Text Data List
while (true)
{
// Block Size(1 byte)
var blockSize = bytes[byteIndex];
byteIndex++;
if (blockSize == 0x00)
{
// Block Terminator(1 byte)
break;
}
var block = new BytesBlock();
block.Size = blockSize;
// Plain Text Data(n byte)
block.Bytes = new byte[block.Size];
for (var index = 0; index < block.Bytes.Length; index++)
{
block.Bytes[index] = bytes[byteIndex];
byteIndex++;
}
Blocks.Add(block);
}
}
public FrameImageDescriptor(byte[] bytes, ref int byteIndex)
{
//描述器标识符 0x2c (1 byte)
Separator = bytes[byteIndex];
byteIndex++;
//图像起始点 (2 byte)
MarginLeft = BitConverter.ToUInt16(bytes, byteIndex);
byteIndex += 2;
//图像起始点 (2 byte)
MarginTop = BitConverter.ToUInt16(bytes, byteIndex);
byteIndex += 2;
//图像宽度 (2 byte)
Width = BitConverter.ToUInt16(bytes, byteIndex);
byteIndex += 2;
//图像高度 (2 byte)
Height = BitConverter.ToUInt16(bytes, byteIndex);
byteIndex += 2;
#region Packet Fields (1 byte) //此处算法参照全局配置
//是否使用局部色表 (1 bit)
LocalColorTableFlag = bytes[byteIndex] >> 7 == 1;
//是否包含交错 (1 bit)
FlagInterlace = (bytes[byteIndex] >> 6) % 2 == 1;
//重要颜色靠前标识 (1 bit)
FlagSort = (bytes[byteIndex] >> 5) % 2 == 1;
//保留字段 (2 bit)
Reserved = (bytes[byteIndex] >> 3) % 4;
//局部色表长度 (3 bit)
int power = bytes[byteIndex] % 8 + 1;
LocalColorTableSize = (int)Math.Pow(2, power);
#endregion
//指针下移
byteIndex++;
LocalColorTable = new Color32[LocalColorTableSize];
//是否包含局部色表,计算方法参照全局色表
if (LocalColorTableFlag)
{
for (int localColorIndex = 0; localColorIndex < LocalColorTableSize; localColorIndex++)
{
LocalColorTable[localColorIndex] = new Color32(bytes[byteIndex], bytes[byteIndex + 1], bytes[byteIndex + 2], 255);
byteIndex += 3;
}
}
//Lzw解码后 拆分成色号的单位bit长度(1 byte)
LzwCodeSize = bytes[byteIndex];
byteIndex++;
var lzwPixelsBlocks = new List <BytesBlock>();
//紧接着是表示色号的lzw压缩后的字节块 结构：长度+数据+长度+数据+...+结尾符
while (true)
{
//字节块长度(1 byte)
var blockSize = bytes[byteIndex];
byteIndex++;
//判断是否为结尾符
if (blockSize == 0x00)
{
break;
}
//初始化字节块
var block = new BytesBlock();
block.Size = blockSize;
block.Bytes = new byte[block.Size];
//字节块赋值
for (var index = 0; index < block.Bytes.Length; index++)
{
block.Bytes[index] = bytes[byteIndex];
byteIndex++;
}
lzwPixelsBlocks.Add(block);
}
LzwPixelsBlocks = lzwPixelsBlocks.ToArray();
}
