`pdfBeginTransparencyGroup`

Begin a template whose Form XObject additionally carries a

int32_t __stdcall pdfBeginTransparencyGroup(PPDF IPDF, double x1, double y1, double x2, double y2, BOOL32 Isolated, BOOL32 Knockout, TExtColorSpace CS, int32_t CSHandle);

Delphi

function pdfBeginTransparencyGroup(const IPDF: PPDF; x1, y1, x2, y2: Double; Isolated, Knockout: LongBool; CS: TExtColorSpace; CSHandle: Integer): Integer; stdcall;

Purpose. Begin a template whose Form XObject additionally carries a /Group transparency-group dictionary (isolated/knockout blending semantics) — built on the same BeginTemplateEx capture mechanism as pdfBeginTemplate above.

Description. CSHandle is accepted by the ABI but never passed through — only the coarse CS: TExtColorSpace ordinal reaches BeginTransparencyGroupH; a caller cannot specify a custom (ICC/Separation/DeviceN) group color space by handle through this call, only a bare device-space ordinal.

Parameters.

Parameter	Description
`IPDF`	Document handle.
`x1,y1,x2,y2`	Group bounding box.
`Isolated`, `Knockout`	Transparency-group blending flags.
`CS`	Device color-space ordinal for the group.
`CSHandle`	Accepted but silently dropped — a custom color-space handle cannot be used here.

Return value. The new template's handle; 0 if IPDF is invalid.

See also. pdfCreateSoftMask (consumes a transparency-group template built this way).

C# (P/Invoke)

wrappers/dotnet/LumasPdf.cs

public static extern int pdfBeginTransparencyGroup(IntPtr IPDF, double x1, double y1, double x2, double y2, [MarshalAs(UnmanagedType.Bool)] bool Isolated, [MarshalAs(UnmanagedType.Bool)] bool Knockout, TExtColorSpace CS, int CSHandle);

Area

Core SDK