<?php
/*
 * Reverse printing
 *
 * "Reverse printing" is the process of printing text or graphical elements by 
 * applying ink to the surrounding area and keeping the text unprinted. When 
 * printing on paper the unmarked area remains in paper color, i.e. usually 
 * white. In flexographic printing (used for package printing on substrates 
 * other than paper) it may be required to apply an additional die color, e.g. 
 * when printing on translucent substrate.
 * The code in this topic draws a solid rectangle with 100% spot color and then 
 * places text with 0% spot color.
 * 
 * Required software: PDFlib/PDFlib+PDI/PPS 10
 * Required data: none
 *
 */

/* This is where the data files are. Adjust as necessary. */
$searchpath = "../input";
$outfile = "";
$title = "Reverse printing";

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);
    
    /* Start the page */
    $p->begin_page_ext(0, 0, "width=a4.height height=a4.width");

    /* Draw a background rectangle and fill it with 100% "PANTONE 463 C". */
    $p->set_graphics_option("fillcolor={spotname {PANTONE 463 C} 1}");

    $p->rect(0, 0, 842, 595);
    $p->fill();

    /* Draw text with the same spot color, but a tint value of 0. Nothing 
     * will be painted because no ink is applied. Due to the colorized 
     * background area the text will be visible nevertheless.
     */
    
    $p->fit_textline("Reverse Printing", 50, 50, 
        "fontname=NotoSerif-Bold fontsize=40 boxsize={742 495} fitmethod=meet " .
        "position=center fillcolor={spotname {PANTONE 463 C} 0}");
    
    $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_printing.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;
?>