property PageWidthZoom[PageNumber: Integer]: Double;
Read-only zoom factor that fits the page width neatly within the view
Useful for building a "Fit Width" toolbar button
All TPdfView display properties trigger a repaint when assigned; you can change several in succession without flicker because the redraw is coalesced into a single invalidation
Active := TruePdfView1.Pdf at run time, reapply any view-only settings — the new TPdf has its own state
begin
PdfView1.PageWidthZoom := {value};
PdfView1.Active := True;
end;