private IGIFBlock ReadImage(BinaryReader aReader, GIFImage aImage)
{
var res = new GIFImageBlock();
res.xPos = aReader.ReadUInt16();
res.yPos = aReader.ReadUInt16();
res.width = aReader.ReadUInt16();
res.height = aReader.ReadUInt16();
res.flags = (EImageDescriptorFlags)aReader.ReadByte();
if (res.HasLocalColorTable)
{
Log("Read local color table: " + res.SizeOfLocalColorTable);
res.usedColorTable =
res.colorTable = ReadColorTable(aReader, res.SizeOfLocalColorTable);
}
else
{
res.colorTable = null;
res.usedColorTable = aImage.screen.globalColorTable;
}
if (lastGrCtrl != null)
{
res.graphicControl = lastGrCtrl;
lastGrCtrl = null;
}
Log("Start LZW");
ReadLZWImage(aReader, res);
return(res);
}
private bool ReadFileHeader(BinaryReader aReader, GIFImage aImage)
{
aImage.header.magic = (uint)(aReader.ReadByte() | (aReader.ReadByte() << 8) | (aReader.ReadByte() << 16));
var ver = aImage.header.version = (uint)(aReader.ReadByte() | (aReader.ReadByte() << 8) | (aReader.ReadByte() << 16));
return(aImage.header.magic == GIFHeader.MAGIC && (ver == GIFHeader.VERSION_87a || ver == GIFHeader.VERSION_89a));
}
public GIFImage Load(BinaryReader aReader)
{
GIFImage img = new GIFImage();
if (!ReadFileHeader(aReader, img))
{
Debug.LogWarning("Gif header magic wrong or unknown version: '" + img.header.Magic + "' / '" + img.header.Version + "'");
return(null);
}
if (!ReadScreenDescriptor(aReader, img))
{
Debug.LogWarning("Error reading GIF screen descriptor or global color table");
return(null);
}
Log("Header read completed");
while (true)
{
var block = ReadBlock(aReader, img);
if (block == null)
{
break;
}
block.Parent = img;
img.data.Add(block);
}
return(img);
}
private IGIFBlock ReadBlock(BinaryReader aReader, GIFImage aImage)
{
byte blockType = aReader.ReadByte();
Log("New block: " + ((EBlockType)blockType));
switch ((EBlockType)blockType)
{
case EBlockType.Extension: return(ReadExtension(aReader));
case EBlockType.ImageDescriptor: return(ReadImage(aReader, aImage));
case EBlockType.Trailer: return(null);
default: throw new System.NotSupportedException("Encountered unknown GIF block type: 0x" + blockType.ToString("xx"));
}
}
private bool ReadScreenDescriptor(BinaryReader aReader, GIFImage img)
{
img.screen.width = aReader.ReadUInt16();
img.screen.height = aReader.ReadUInt16();
img.screen.flags = (EScreenDescriptorFlags)aReader.ReadByte();
img.screen.bgColorIndex = aReader.ReadByte();
img.screen.pixelAspectRatio = aReader.ReadByte();
if (img.screen.HasGlobalColorTable)
{
img.screen.globalColorTable = ReadColorTable(aReader, img.screen.SizeOfGlobalColorTable);
}
else
{
img.screen.globalColorTable = null;
}
return(img.screen.HasGlobalColorTable ^ img.screen.globalColorTable == null);
}