private static void SetImageBlock(byte[] gifBytes, ref int byteIndex, ref GifData gifData)
{
ImageBlock ib = new ImageBlock();
// Image Separator(1 Byte)
// 0x2c
ib.m_imageSeparator = gifBytes[byteIndex];
byteIndex++;
// Image Left Position(2 Bytes)
ib.m_imageLeftPosition = BitConverter.ToUInt16(gifBytes, byteIndex);
byteIndex += 2;
// Image Top Position(2 Bytes)
ib.m_imageTopPosition = BitConverter.ToUInt16(gifBytes, byteIndex);
byteIndex += 2;
// Image Width(2 Bytes)
ib.m_imageWidth = BitConverter.ToUInt16(gifBytes, byteIndex);
byteIndex += 2;
// Image Height(2 Bytes)
ib.m_imageHeight = BitConverter.ToUInt16(gifBytes, byteIndex);
byteIndex += 2;
// 1 Byte
{
// Local Color Table Flag(1 Bit)
ib.m_localColorTableFlag = (gifBytes[byteIndex] & 128) == 128; // 0b10000000
// Interlace Flag(1 Bit)
ib.m_interlaceFlag = (gifBytes[byteIndex] & 64) == 64; // 0b01000000
// Sort Flag(1 Bit)
ib.m_sortFlag = (gifBytes[byteIndex] & 32) == 32; // 0b00100000
// Reserved(2 Bits)
// Unused
// Size of Local Color Table(3 Bits)
int val = (gifBytes[byteIndex] & 7) + 1;
ib.m_sizeOfLocalColorTable = (int)Math.Pow(2, val);
byteIndex++;
}
if (ib.m_localColorTableFlag)
{
// Local Color Table(0～255×3 Bytes)
ib.m_localColorTable = new List <byte[]>();
for (int i = byteIndex; i < byteIndex + (ib.m_sizeOfLocalColorTable * 3); i += 3)
{
ib.m_localColorTable.Add(new byte[] { gifBytes[i], gifBytes[i + 1], gifBytes[i + 2] });
}
byteIndex = byteIndex + (ib.m_sizeOfLocalColorTable * 3);
}
// LZW Minimum Code Size(1 Byte)
ib.m_lzwMinimumCodeSize = gifBytes[byteIndex];
byteIndex++;
// Block Size & Image Data List
while (true)
{
// Block Size(1 Byte)
byte blockSize = gifBytes[byteIndex];
byteIndex++;
if (blockSize == 0x00)
{
// Block Terminator(1 Byte)
break;
}
var imageDataBlock = new ImageBlock.ImageDataBlock();
imageDataBlock.m_blockSize = blockSize;
// Image Data(? Bytes)
imageDataBlock.m_imageData = new byte[imageDataBlock.m_blockSize];
for (int i = 0; i < imageDataBlock.m_imageData.Length; i++)
{
imageDataBlock.m_imageData[i] = gifBytes[byteIndex];
byteIndex++;
}
if (ib.m_imageDataList == null)
{
ib.m_imageDataList = new List <ImageBlock.ImageDataBlock>();
}
ib.m_imageDataList.Add(imageDataBlock);
}
if (gifData.m_imageBlockList == null)
{
gifData.m_imageBlockList = new List <ImageBlock>();
}
gifData.m_imageBlockList.Add(ib);
}
static void SetImageBlock (byte[] gifBytes, ref int byteIndex, ref GifData gifData)
{
ImageBlock ib = new ImageBlock ();
// Image Separator(1 Byte)
// 0x2c
ib.imageSeparator = gifBytes[byteIndex];
byteIndex++;
// Image Left Position(2 Bytes)
ib.imageLeftPosition = BitConverter.ToUInt16 (gifBytes, byteIndex);
byteIndex += 2;
// Image Top Position(2 Bytes)
ib.imageTopPosition = BitConverter.ToUInt16 (gifBytes, byteIndex);
byteIndex += 2;
// Image Width(2 Bytes)
ib.imageWidth = BitConverter.ToUInt16 (gifBytes, byteIndex);
byteIndex += 2;
// Image Height(2 Bytes)
ib.imageHeight = BitConverter.ToUInt16 (gifBytes, byteIndex);
byteIndex += 2;
// 1 Byte
{
// Local Color Table Flag(1 Bit)
ib.localColorTableFlag = (gifBytes[byteIndex] & 128) == 128; // 0b10000000
// Interlace Flag(1 Bit)
ib.interlaceFlag = (gifBytes[byteIndex] & 64) == 64; // 0b01000000
// Sort Flag(1 Bit)
ib.sortFlag = (gifBytes[byteIndex] & 32) == 32; // 0b00100000
// Reserved(2 Bits)
// Unused
// Size of Local Color Table(3 Bits)
int val = (gifBytes[byteIndex] & 7) + 1;
ib.sizeOfLocalColorTable = (int) Math.Pow (2, val);
byteIndex++;
}
if (ib.localColorTableFlag) {
// Local Color Table(0～255×3 Bytes)
ib.localColorTable = new List<byte[]> ();
for (int i = byteIndex; i < byteIndex + (ib.sizeOfLocalColorTable * 3); i += 3) {
ib.localColorTable.Add (new byte[] { gifBytes[i], gifBytes[i + 1], gifBytes[i + 2] });
}
byteIndex = byteIndex + (ib.sizeOfLocalColorTable * 3);
}
// LZW Minimum Code Size(1 Byte)
ib.LzwMinimumCodeSize = gifBytes[byteIndex];
byteIndex++;
// Block Size & Image Data List
while (true) {
// Block Size(1 Byte)
byte blockSize = gifBytes[byteIndex];
byteIndex++;
if (blockSize == 0x00) {
// Block Terminator(1 Byte)
break;
}
var imageDataBlock = new ImageBlock.ImageDataBlock ();
imageDataBlock.blockSize = blockSize;
// Image Data(? Bytes)
imageDataBlock.imageData = new byte[imageDataBlock.blockSize];
for (int i = 0; i < imageDataBlock.imageData.Length; i++) {
imageDataBlock.imageData[i] = gifBytes[byteIndex];
byteIndex++;
}
if (ib.imageDataList == null) {
ib.imageDataList = new List<ImageBlock.ImageDataBlock> ();
}
ib.imageDataList.Add (imageDataBlock);
}
if (gifData.imageBlockList == null) {
gifData.imageBlockList = new List<ImageBlock> ();
}
gifData.imageBlockList.Add (ib);
}
