`pdfSetFieldFont`

Set a form field's /DA (Default Appearance) font name and

Category	Form field fonts
Exported names	`pdfSetFieldFontA`, `pdfSetFieldFontW`
Note	`Style`/`Embed`/`CP` accepted but unused (see Remarks)

Purpose — Set a form field's /DA (Default Appearance) font name and size directly.

Description — Rewrites the field's /DA string as /<Name> <Size> Tf <existing color ops>, preserving whatever color operators were already present. Name is written as a bare resource name reference — it is not validated against the field's /DR (default resources) font dictionary, so if Name doesn't correspond to a real resource entry, rendering falls to viewer-specific substitution.

Declarations

int32_t __stdcall pdfSetFieldFontA(PPDF IPDF, uint32_t Field, const char* Name, int32_t Style, double Size, BOOL32 Embed, TCodepage CP);
int32_t __stdcall pdfSetFieldFontW(PPDF IPDF, uint32_t Field, const wchar_t* Name, int32_t Style, double Size, BOOL32 Embed, TCodepage CP);

Delphi

function pdfSetFieldFontA(const IPDF: PPDF; Field: Cardinal; const Name: PAnsiChar; Style: Integer; Size: Double; Embed: LongBool; CP: TCodepage): Integer; stdcall; external 'LumasPdf.dll';
function pdfSetFieldFontW(const IPDF: PPDF; Field: Cardinal; const Name: PWideChar; Style: Integer; Size: Double; Embed: LongBool; CP: TCodepage): Integer; stdcall; external 'LumasPdf.dll';

Parameters

Parameter	Type	Description
`IPDF`	`PPDF`	Instance handle.
`Field`	`Cardinal`	Target field handle.
`Name`	string	Font resource name written verbatim into `/DA`. `Size <= 0` keeps the field's existing `/DA` size instead of clearing it.
`Style`	`Integer`	Accepted but not read.
`Size`	`Double`	New font size, or `<= 0` to keep the existing size.
`Embed`	`BOOL32`	Accepted but not read — this call never touches font embedding, only the `/DA` string.
`CP`	`TCodepage`	Accepted but not read.

Return value — 1 on success; 0 if Field doesn't resolve to a known field.

See also — pdfSetFieldFontSize

C# (P/Invoke)

wrappers/dotnet/LumasPdf.cs

public static extern int pdfSetFieldFontA(IntPtr IPDF, uint Field, [MarshalAs(UnmanagedType.LPStr)] string Name, int Style, double Size, [MarshalAs(UnmanagedType.Bool)] bool Embed, TCodepage CP);
public static extern int pdfSetFieldFontW(IntPtr IPDF, uint Field, [MarshalAs(UnmanagedType.LPWStr)] string Name, int Style, double Size, [MarshalAs(UnmanagedType.Bool)] bool Embed, TCodepage CP);

Area

Fonts