Replicating example 6 of TCPDF. Getting error "No such file or directory" for image files

Question

I am trying to make the example 6 of TCPDF: WriteHTML()

This is the error I get

A PHP Error was encountered

Severity: Warning

Message: imagecreatefrompng(images/logo_example.png): failed to open stream: 
No such file or directory

This is the code for my view /application/views/reporte_pog.php

<?php

// create new PDF document
$pdf = new TCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);

// set document information
$pdf->SetCreator(PDF_CREATOR);
$pdf->SetAuthor('Nicola Asuni');
$pdf->SetTitle('TCPDF Example 006');
$pdf->SetSubject('TCPDF Tutorial');
$pdf->SetKeywords('TCPDF, PDF, example, test, guide');

// set default header data
$pdf->SetHeaderData(PDF_HEADER_LOGO, PDF_HEADER_LOGO_WIDTH, PDF_HEADER_TITLE.' 006', PDF_HEADER_STRING);

// set header and footer fonts
$pdf->setHeaderFont(Array(PDF_FONT_NAME_MAIN, '', PDF_FONT_SIZE_MAIN));
$pdf->setFooterFont(Array(PDF_FONT_NAME_DATA, '', PDF_FONT_SIZE_DATA));

// set default monospaced font
$pdf->SetDefaultMonospacedFont(PDF_FONT_MONOSPACED);

// set margins
$pdf->SetMargins(PDF_MARGIN_LEFT, PDF_MARGIN_TOP, PDF_MARGIN_RIGHT);
$pdf->SetHeaderMargin(PDF_MARGIN_HEADER);
$pdf->SetFooterMargin(PDF_MARGIN_FOOTER);

// set auto page breaks
$pdf->SetAutoPageBreak(TRUE, PDF_MARGIN_BOTTOM);

// set image scale factor
$pdf->setImageScale(PDF_IMAGE_SCALE_RATIO);

// set some language-dependent strings (optional)
if (@file_exists(dirname(__FILE__).'/lang/eng.php')) {
    require_once(dirname(__FILE__).'/lang/eng.php');
    $pdf->setLanguageArray($l);
}

// ---------------------------------------------------------

// set font
$pdf->SetFont('dejavusans', '', 10);

// add a page
$pdf->AddPage();

// writeHTML($html, $ln=true, $fill=false, $reseth=false, $cell=false, $align='')
// writeHTMLCell($w, $h, $x, $y, $html='', $border=0, $ln=0, $fill=0, $reseth=true, $align='', $autopadding=true)



// create some HTML content
$html = '<h1>HTML Example</h1>
Some special characters: &lt; € &euro; &#8364; &amp; è &egrave; &copy; &gt; \\slash \\\\double-slash \\\\\\triple-slash
<h2>List</h2>
List example:
<ol>
    <li><img src="images/logo_example.png" alt="test alt attribute" width="30" height="30" border="0" /> test image</li>
    <li><b>bold text</b></li>
    <li><i>italic text</i></li>
    <li><u>underlined text</u></li>
    <li><b>b<i>bi<u>biu</u>bi</i>b</b></li>
    <li><a href="http://www.tecnick.com" dir="ltr">link to http://www.tecnick.com</a></li>
    <li>Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo.<br />Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt.</li>
    <li>SUBLIST
        <ol>
            <li>row one
                <ul>
                    <li>sublist</li>
                </ul>
            </li>
            <li>row two</li>
        </ol>
    </li>
    <li><b>T</b>E<i>S</i><u>T</u> <del>line through</del></li>
    <li><font size="+3">font + 3</font></li>
    <li><small>small text</small> normal <small>small text</small> normal <sub>subscript</sub> normal <sup>superscript</sup> normal</li>
</ol>
<dl>
    <dt>Coffee</dt>
    <dd>Black hot drink</dd>
    <dt>Milk</dt>
    <dd>White cold drink</dd>
</dl>
<div style="text-align:center">IMAGES<br />
<img src="images/logo_example.png" alt="test alt attribute" width="100" height="100" border="0" /><img src="images/tcpdf_box.svg" alt="test alt attribute" width="100" height="100" border="0" /><img src="images/logo_example.jpg" alt="test alt attribute" width="100" height="100" border="0" />
</div>';

// output the HTML content
$pdf->writeHTML($html, true, false, true, false, '');


//Close and output PDF document
$pdf->Output('example_006.pdf', 'I');

//============================================================+
// END OF FILE
//============================================================+
?>

The images folder is located in applications/libraries/tcpdf/examples/images

I already tried other examples from TCPDF webpage and they have worked, like creating custom functions for the header and footer. I already tried with the full path for the images folder but that is not working either.

Answer 1

You should move your images out of the application side of your code into a more public level.

Generally people store their public assets I.e Imgs/Js/Css at base level.

Eg /var/www/html/site/assets/images/ this means when referencing your assets you simply need to use ./images/logo_example.png rather than hoping/worrying whether the assets will be in the right place relative the script you are running.

It also means when serving this code to the public you can secure your application code from any direct access while still allowing access to the assets.

So in short, move your images to the base /var/www/html/site/assets/images/ and from your script instead of:

 <img src="images/logo_example.png">

Have

 <img src="./assets/images/logo_example.png">

Make that change and you'll no longer have the missing image error. TCPDF is clearly just looking in the wrong place at the moment.

On top of everything I've just said, it's also very helpful to anyone who may pick up your code in the future to know all assets are in one place, instead of trawling through directories trying to find them. It may even benefit you in a months time when you forget where you put them.