pdfSetCompressionLevel

int32_t __stdcall pdfGetCompressionLevel(PPDF IPDF);
BOOL32 __stdcall pdfSetCompressionLevel(PPDF IPDF, int32_t CompressLevel);

function pdfGetCompressionLevel(const IPDF: PPDF): Integer; stdcall;
function pdfSetCompressionLevel(const IPDF: PPDF; CompressLevel: Integer): LongBool; stdcall;

Purpose. Set/get the Flate/zlib compression level (0..9) used throughout the serializer for every compressible stream — content streams, ICC profiles, CMap streams, embedded files, thumbnails, patterns, templates, alpha channels, and more.

Description. Verified thoroughly real and widely consumed — grep confirms FCompressionLevel (default 1, an explicit DIFF from the classic API's default) gates a FlateCompress call at more than a dozen distinct serialization sites across essentially every stream-producing code path in the document. <= 0 disables Flate compression entirely at each of those sites (streams are written uncompressed).

Parameters.

Return value. Getter: the current level (default 1); 0 if IPDF invalid. Setter: True if IPDF valid.

C# (P/Invoke)

[return: MarshalAs(UnmanagedType.Bool)]