`pdfGetKerning`

Look up the kerning adjustment for a specific character

int32_t __stdcall pdfGetKerningA(PPDF IPDF, const char* CharPair);
int32_t __stdcall pdfGetKerningW(PPDF IPDF, const wchar_t* CharPair);
int32_t __stdcall pdfUseKerning(PPDF IPDF, int32_t Kern);

Delphi

function pdfGetKerningA(const IPDF: PPDF; CharPair: PAnsiChar): Integer; stdcall;
function pdfGetKerningW(const IPDF: PPDF; CharPair: PWideChar): Integer; stdcall;
function pdfUseKerning(const IPDF: PPDF; Kern: Integer): Integer; stdcall;

Purpose. Look up the kerning adjustment for a specific character pair in the current font; enable/disable automatic kerning application.

Description. Known limitations for both. pdfGetKerningA/W always returns 0 regardless of CharPair — per an explicit source comment on the underlying GetKerningPair: "no kern-pair data available in the current font model." pdfUseKerning stores its flag (FUseKerning) but the field is known to have no read-site anywhere — no text-writing code path consults it, so automatic kerning is never actually applied or suppressed by this call regardless of value.

Parameters.

Parameter	Description
`IPDF`	Document handle.
`CharPair`	(GetKerning only) The 2-character pair to look up — never resolves to a non-zero value.
`Kern`	(UseKerning only) Stored but never consulted.

Return value. pdfGetKerning: always 0 for a valid IPDF (no kerning data exists to look up). pdfUseKerning: 1 if IPDF valid.

C# (P/Invoke)

wrappers/dotnet/LumasPdf.cs

public static extern int pdfGetKerningW(IntPtr IPDF, IntPtr CharPair);
public static extern int pdfGetKerning(IntPtr IPDF, IntPtr CharPair);
public static extern int pdfGetKerningA(IntPtr IPDF, IntPtr CharPair);

Area

Core SDK