setViewerPreference method
Sets a boolean viewer preference.
Implementation
void setViewerPreference(String key, bool? value) {
final existing = _catalog[PdfNameTokens.viewerPreferences];
final preferences = existing is PdfDict
? existing
: (_materializeDict(existing) ?? PdfDict());
if (!identical(existing, preferences)) {
_catalog[PdfNameTokens.viewerPreferences] = preferences;
}
if (value == null) {
preferences.values.remove(key);
} else {
preferences[key] = PdfBool(value);
}
}