/// <summary>Resets the frame state before reading the next image</summary>
protected void ResetFrame()
{
lastDispose = dispose;
lastImage = image;
lastBgColor = bgColor;
transparency = false;
delay = 0;
localColorTable = null;
dispose = DisposeMode.NoAction;
}
/// <summary>Reads the Graphic Control Extension values</summary>
protected void ReadGraphicControlExt()
{
Read(); // block size
int packed = Read(); // packed fields
dispose = (DisposeMode)((packed & 0x1c) >> 2); // disposal method
if (dispose == DisposeMode.NoAction)
{
dispose = DisposeMode.LeaveInPlace; // elect to keep old image if discretionary
}
transparency = (packed & 1) != 0;
delay = ReadShort() * 10; // delay in milliseconds
transIndex = Read(); // transparent color index
Read(); // block terminator
}