Set the active page for graphics output.
procedure SetActivePage(Page: Word);
Makes Page the active graphics page, directing all subsequent graphics output to Page.
Multiple pages are only supported by the EGA (256K), VGA, and Hercules graphics cards. With multiple graphics pages, a program can direct graphics output to an offscreen page, then quickly display the offscreen image by changing the visual page with the SetVisualPage procedure. This technique is especially useful for animation.
Must be in graphics mode.