TGIFPlainTextExtensionRec = packed record
  BlockSize: byte;
  Height: Word;
  Left: Word;
  Top: Word;
  Width: Word;
  CellHeight: Byte;
  CellWidth: Byte;
  TextBGColorIndex: Byte;
  TextFGColorIndex: Byte;
end;

struct TGIFPlainTextExtensionRec {
  byte BlockSize;
  Word Height;
  Word Left;
  Word Top;
  Word Width;
  Byte CellHeight;
  Byte CellWidth;
  Byte TextBGColorIndex;
  Byte TextFGColorIndex;
};