Visibility

Add-On Visibility

Informations

Author:Olivier
License: FPDF

Description

This script allows to restrict the rendering of some elements to screen or printout. This can be useful, for instance, to put a background image or color that will show on screen but won't print.

SetVisibility(string v)

v can take one of the following values:

all: always visible
print: visible only when printed
screen: visible only when displayed on screen

Note: this feature is not supported by all PDF viewers.

Source

<?php
require('fpdf.php');

class PDF_Visibility extends FPDF
{
    protected $visibility = 'all';
    protected $n_ocg_print;
    protected $n_ocg_view;

    function SetVisibility($v)
    {
        if($this->visibility!='all')
            $this->_out('EMC');
        if($v=='print')
            $this->_out('/OC /OC1 BDC');
        elseif($v=='screen')
            $this->_out('/OC /OC2 BDC');
        elseif($v!='all')
            $this->Error('Incorrect visibility: '.$v);
        $this->visibility = $v;
    }

    function _endpage()
    {
        $this->SetVisibility('all');
        parent::_endpage();
    }

    function _enddoc()
    {
        if($this->PDFVersion<'1.5')
            $this->PDFVersion = '1.5';
        parent::_enddoc();
    }

    function _putocg()
    {
        $this->_newobj();
        $this->n_ocg_print = $this->n;
        $this->_put('<</Type /OCG /Name '.$this->_textstring('print'));
        $this->_put('/Usage <</Print <</PrintState /ON>> /View <</ViewState /OFF>>>>>>');
        $this->_put('endobj');
        $this->_newobj();
        $this->n_ocg_view = $this->n;
        $this->_put('<</Type /OCG /Name '.$this->_textstring('view'));
        $this->_put('/Usage <</Print <</PrintState /OFF>> /View <</ViewState /ON>>>>>>');
        $this->_put('endobj');
    }

    function _putresources()
    {
        $this->_putocg();
        parent::_putresources();
    }

    function _putresourcedict()
    {
        parent::_putresourcedict();
        $this->_put('/Properties <</OC1 '.$this->n_ocg_print.' 0 R /OC2 '.$this->n_ocg_view.' 0 R>>');
    }

    function _putcatalog()
    {
        parent::_putcatalog();
        $p = $this->n_ocg_print.' 0 R';
        $v = $this->n_ocg_view.' 0 R';
        $as = "<</Event /Print /OCGs [$p $v] /Category [/Print]>> <</Event /View /OCGs [$p $v] /Category [/View]>>";
        $this->_put("/OCProperties <</OCGs [$p $v] /D <</ON [$p] /OFF [$v] /AS [$as]>>>>");
    }
}
?>

Example

<?php
require('visibility.php');

$pdf = new PDF_Visibility();
$pdf->AddPage();
$pdf->SetFont('Arial', '', 14);
$pdf->SetVisibility('screen');
$pdf->Write(6, "This line is displayed on screen.\n");
$pdf->SetVisibility('print');
$pdf->Write(6, "This line is printed.\n");
$pdf->SetVisibility('all');
$pdf->Output();
?>

View the result here.

Download

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