<?php
/*
 * Reverse page order:
 * Create pages in reverse page order
 *
 * Create page no. 5 first, then page no. 4, etc.
 *
 * Required software: PDFlib/PDFlib+PDI/PPS 10
 * Required data: PDF document
 */
/* This is where the data files are. Adjust as necessary. */
$searchpath = dirname(__FILE__,3)."/input";
$outfile = "";
$title = "Reverse Page Order";

$lastpage = 5; $step = 1;

try {
    $p = new pdflib();

    $p->set_option("searchpath={" . $searchpath . "}");

    /* This means we must check return values of load_font() etc. */
    $p->set_option("errorpolicy=return");

    if ($p->begin_document($outfile, "") == 0)
        throw new Exception("Error: " . $p->get_errmsg());

    $p->set_info("Creator", "PDFlib Cookbook");
    $p->set_info("Title", $title);

    /* Loop over all subsequent pages in reverse order */
    for ($pageno = $lastpage, $step = 1; $pageno > 0; $pageno--, $step++)
    {
        if ($pageno == $lastpage)
            /* Create the first page */
            $p->begin_page_ext(0, 0, "width=a4.width height=a4.height");
        else
            /* Insert subsequent pages before what is (currently) the
             * first page */
            $p->begin_page_ext(0, 0,
                "width=a4.width height=a4.height pagenumber=1");

        /* Place a text line indicating the page number */
        $p->fit_textline("Page " . $pageno . " created in step " . $step,
            100, 500, 
            "fontname=NotoSerif-Bold fontsize=24");

        $p->end_page_ext("");
    }

    $p->end_document("");

    $buf = $p->get_buffer();
    $len = strlen($buf);

    header("Content-type: application/pdf");
    header("Content-Length: $len");
    header("Content-Disposition: inline; filename=reverse_page_order.pdf");
    print $buf;

} catch (PDFlibException $e) {
    echo("PDFlib exception occurred:\n".
        "[" . $e->get_errnum() . "] " . $e->get_apiname() .
        ": " . $e->get_errmsg() . "\n");
    exit(1);
} catch (Throwable $e) {
    echo("PHP exception occurred: " . $e->getMessage() . "\n");
    exit(1);
}

$p = 0;

?>