property Visible: Boolean; // published, inherited from TControl
Setting Visible := False removes the viewer from the screen without destroying it; the underlying PDFium document, current page, zoom factor and selection state are all preserved. When the property is set back to True den bufrede tilstanden vises umiddelbart på nytt og en omtegning settes i kø automatisk
Hiding the viewer is the canonical way to swap between alternative document views (for example a thumbnail-only mode and the full reader) without recreating the component. Because PDFium page handles are kept open while hidden, the user can toggle quickly between views with no reload delay.
Visibility also propagates through container controls: if the parent panel is invisible, the viewer is invisible regardless of its own setting. The framework still raises OnShow / OnHide varsler på skjemaet slik at applikasjonskode kan synkronisere verktøylinjer tilsvarende
True on a published TWinControl.PdfView1.Active := False or Pdf1.Close.AsyncRendering := False beforehand — otherwise queued rendering may continue briefly.
// Toggle between thumbnail mode and full reader on a button click
procedure TForm1.btnToggleViewClick(Sender: TObject);
begin
ThumbnailGrid.Visible := PdfView1.Visible;
PdfView1.Visible := not PdfView1.Visible;
if PdfView1.Visible then
PdfView1.SetFocus;
end;