`pdfSetWatermarkText`

Configure a diagonal text watermark stamped on every page

Category	Document decoration
Exported names	`pdfSetWatermarkTextA`, `pdfSetWatermarkTextW`, `pdfSetWatermarkText`
Note	deferred application (see Remarks)

Purpose — Configure a diagonal text watermark stamped on every page of the output document.

Description — Stores the watermark configuration; FontSize <= 0 is replaced with a default of 48, and Opacity is clamped to [0, 1]. Setting an empty Text disables the watermark (FWmEnabled := Text <> '').

Declarations

BOOL32 __stdcall pdfSetWatermarkTextA(PPDF IPDF, const char* Text, double FontSize, uint32_t Color, double Angle, double Opacity);
BOOL32 __stdcall pdfSetWatermarkTextW(PPDF IPDF, const wchar_t* Text, double FontSize, uint32_t Color, double Angle, double Opacity);

Delphi

function pdfSetWatermarkTextA(const IPDF: PPDF; Text: PAnsiChar; FontSize: Double; Color: Cardinal; Angle, Opacity: Double): LongBool; stdcall; external 'LumasPdf.dll';
function pdfSetWatermarkTextW(const IPDF: PPDF; Text: PWideChar; FontSize: Double; Color: Cardinal; Angle, Opacity: Double): LongBool; stdcall; external 'LumasPdf.dll';

Parameters

Parameter	Type	Description
`IPDF`	`PPDF`	Instance handle.
`Text`	string	Watermark text. Supports `[page]`/`[pages]` token substitution (case-insensitive) for the current page number and total page count — the same substitution mechanism used by header/footer text. Empty string disables the watermark.
`FontSize`	`Double`	`<= 0` is replaced with `48`.
`Color`	`Cardinal`	Fill color (engine's packed color format).
`Angle`	`Double`	Rotation in degrees.
`Opacity`	`Double`	Clamped to `[0, 1]`; values `< 1` create a transient `ExtGState` for transparency.

Return value — Always TRUE on a valid handle.

Remarks — deferred, document-wide application, always Helvetica. The watermark is not drawn when this call is made. It is applied to every page in the document — including pages already written before this call — during the deferred decoration pass that runs once at close time (guarded by FDecorationsApplied so it only runs once). The watermark font is always Helvetica; there is no way to choose a different font for the watermark text through this API. If the same instance is running in unlicensed trial mode (pdfSetTrialMode(True) and no valid license key), a second, separate "LumasPDF DEMO" stamp is added automatically alongside your watermark on every page — this trial stamp is independent of and unrelated to pdfSetWatermarkText.

See also — pdfSetTrialMode, pdfIsLicensed

C# (P/Invoke)

wrappers/dotnet/LumasPdf.cs

[return: MarshalAs(UnmanagedType.Bool)]

Area

Text