DECOMPRESSDATA (original) (raw)
Summary
The DECOMPRESSDATA structure provides decompression to the L_DecompressBuffer function.
Syntax
Members
uStructSize
Size of this structure in bytes, for versioning. Use the sizeof() operator to calculate this value.
pBuffer
Pointer to the raw compressed data.
nWidth
Width of the uncompressed strip or tile, in bytes.
nHeight
Height of the uncompressed strip or tile, in bytes. If the image consists of a single compressed strip, as with TWAIN, this is the height of the image.
uOffset
Offset of the strip, relative to the buffer. This is usually zero.
nBufferSize
Size of the strip before decompression. For TWAIN, this is the buffer size determined by DAT_SETUPMEMXFER.
nRow
Row offset of the tile or strip.
nCol
Column offset of the tile or strip.
uFlags
Flags that indicate whether which part of a strip or tile is being processed. Possible values are:
| Value | Meaning |
|---|---|
| DECOMPRESS_STRIP_START | Processing the beginning of a tile or strip. |
| DECOMPRESS_STRIP_END | Processing the end of a tile or strip. |
| DECOMPRESS_CHUNK_COMPLETE | Process a complete tile or strip. This is the same as DECOMPRESS_STRIP_START | DECOMPRESS_STRIP_END. |
nReserved1
Reserved for future use. Pass 0.
Comments
If pBuffer does not point to a full tile or strip, set uFlags to DECOMPRESS_STRIP_START when the tile/strip begins and set it to DECOPMRESS_STRIP_END when the tile/strip ends.
Some functions which take this structure as a parameter require that the structure be initialized prior to the function call. You must set the uStructSize member to the total size, in bytes, of the structure. Use the sizeof() operator to calculate this value. Functions that do not require the structure be initialized will take the total size of the structure, in bytes, as an additional function parameter.