THPDFJBIG2Decoder Class

THPDFJBIG2Decoder = class
  constructor Create;
  function LoadFromByteArray(ImageData, GlobalData: TJBIG2ByteArray): Boolean; overload;
  function LoadFromByteArray(ImageData: TJBIG2ByteArray): Boolean; overload;
  function LoadRegionFromByteArray(ImageData, GlobalData: TJBIG2ByteArray;
    RegionLeft, RegionTop, RegionWidth, RegionHeight: Integer): Boolean; overload;
  function LoadRegionFromByteArray(ImageData: TJBIG2ByteArray;
    RegionLeft, RegionTop, RegionWidth, RegionHeight: Integer): Boolean; overload;
  function GetScanline(Row: Integer; var Data: TJBIG2ByteArray): Boolean;
  property Width: Integer read FWidth;
  property Height: Integer read FHeight;
  property ScanlineByteWidth: Integer read FScanlineByteWidth;
  property LastRegionDecodeStats: TJBIG2RegionDecodeStats read FLastRegionDecodeStats;
  property UsedIncrementalRegionDecode: Boolean read FUsedIncrementalRegionDecode;
  property LastSegmentGraphValidationInfo: TJBIG2SegmentGraphValidationInfo
    read FLastSegmentGraphValidationInfo;
end;

解码 JBIG2 图像数据（可选用共享的全局数据），并把结果暴露为整页位图或有边界的区域窗口

LoadFromByteArray 解码完整页面，而 LoadRegionFromByteArray 只解码请求的矩形区域，并通过 UsedIncrementalRegionDecode 报告是否走了增量路径

GetScanline 逐行返回已解码的 scanline 字节，LastRegionDecodeStats 加上 LastSegmentGraphValidationInfo 则暴露每次调用的统计信息和 segment 图检查结果

JBIG2 Compression Support