SetMissingGlyphCallback

Text, fonts, callbacks

Description

Registers an optional callback that can observe a missing Unicode scalar and select report or abort behaviour for that event

Syntax

Delphi

TPDFlibMissingGlyphEvent= Procedure(Sender: TObject;
  CodePoint: Cardinal; UTF16Index, Page: Integer;
  Const FontName, Operation: WideString; Var Action: Integer) Of Object;

PDFlib.OnMissingGlyph:= MissingGlyphHandler;

ActiveX

Function PDFlib::SetMissingGlyphCallback(Callback As Object) As Long

Function Callback.MissingGlyph(CodePoint As Long, UTF16Index As Long,
  Page As Long, FontName As String, Operation As String) As Long

DLL

typedef int (__stdcall *TPDFlibMissingGlyphCallback)(
  uint32_t CodePoint, int UTF16Index, int Page,
  const wchar_t* FontName, const wchar_t* Operation, void* UserData);

int DLSetMissingGlyphCallback(int InstanceID,
  TPDFlibMissingGlyphCallback Callback, void* UserData);

Parameters

CodePoint	The complete Unicode scalar value
UTF16Index	The zero-based source index of the scalar or shaped cluster
Page	The selected one-based page number or zero when no page is active
FontName	The selected font program or resource name
Operation	The text operation that detected the missing glyph
Action	The current policy on entry; return or assign 0 to report and drop, or 1 to abort

Return values

The registration methods return 1 for a valid instance

Remarks

The event is added to the retained report before the callback runs

DLL text pointers are read-only and valid only for the duration of the callback

Exceptions crossing the DLL or ActiveX callback boundary are contained and fall back to report-and-drop behaviour