SetStructElemAltTextA

Označeni PDF & pristupačnost

Opis

Sufiks A na kraju označuje ulaznu točku DLL-a vrste ANSI (char); sučelje ActiveX/COM izlaže samo oblik Unicode. Ponašanje je jednako SetStructElemAltText, a znakovni argumenti tumače se pomoću trenutne kodne stranice SetAnsiMode

Sets the /Alt entry on the structure element currently being built on the tag stack. Alternative text is the text description that assistive technology (screen readers, braille displays) presents to users when the element cannot be rendered visually — for example, an image, figure, or mathematical formula.

Ova je funkcija ekvivalentna prosljeđivanju nepraznog argumenta AltText funkcijama BeginTag ili BeginTagEx, ali dopušta da se alternativni tekst postavi ili ažurira nakon što je element otvoren. Korisno je kada se opis izračunava ili dohvaća asinkrono nakon što je poznata vrsta elementa

Sintaksa

Delphi

Function DLSetStructElemAltTextA(InstanceID: Integer; AltText: PAnsiChar): Integer;

DLL

int DLSetStructElemAltTextA(int InstanceID, const char * AltText);

Parametri

Povratna vrijednost

Povratne vrijednosti 1 on success, 0 if no structure element is currently open or no document is selected.

Napomene

Pozovite ovu funkciju odmah nakon BeginTag dok je ciljni element na vrhu oznakovnog stoga ili u bilo kojem trenutku prije odgovarajućeg poziva EndTag.

AltText and ActualText serve different purposes. AltText is a complete textual substitute for the entire element — it replaces the visual content for users who cannot perceive the rendered output. ActualText (ISO 32000-1 §14.9.4) provides the exact Unicode character sequence for inline glyphs whose extracted text would otherwise be incorrect (such as ligatures), and does not replace rendering. Screen readers typically speak AltText for Figure and Formula elements, and use ActualText for character-level corrections.

ISO 32000-1 §14.9.3 defines the /Alt entry. PDF/UA-1 (ISO 14289-1 §7.5) requires alternative descriptions on Figure and Formula structure elements. GetPDFUADiagnostics reports the FIGURE-NO-ALT:N issue code when Figure or Formula elements are missing Alt text.

Primjer

// Tag an embedded chart image with alternative text
PDFlib.BeginTag('Figure', '', '');
PDFlib.SetStructElemAltText('Bar chart: Q1 sales 120, Q2 sales 145, Q3 sales 98');
PDFlib.SetStructElemBBox(x, y, x + w, y + h);
PDFlib.DrawImage(imgHandle, x, y, w, h);
PDFlib.EndTag;

Vidi također

BeginTag, BeginTagEx, SetStructElemActualText, SetStructElemLang, GetPDFUADiagnostics