169 lines
8.6 KiB
PHP
169 lines
8.6 KiB
PHP
<?php
|
|
|
|
/**
|
|
* E016_pdfua1.php
|
|
*
|
|
* Demonstrates HTML auto-tagging in 'pdfua1' (PDF/UA-1, ISO 14289-1) mode.
|
|
*
|
|
* PDF/UA-1 is the original accessible-PDF profile, standardised as ISO 14289-1:2012
|
|
* and built on PDF 1.7. When this mode is active, tc-lib-pdf:
|
|
* - Writes StructTreeRoot, ParentTree, and MarkInfo /Marked true
|
|
* - Forces ViewerPreferences /DisplayDocTitle true
|
|
* - Sets /Lang from the document language (default en-US)
|
|
* - Clamps heading levels to prevent skipped H1-H6 levels
|
|
* - Emits ActualText for ligatures and special glyphs
|
|
*
|
|
* Every HTML element rendered by addHTMLCell() is automatically mapped to the
|
|
* corresponding PDF structure role — no beginStructElem() calls required.
|
|
* Compare with E063 which builds the same structure tree manually.
|
|
*
|
|
* Auto-tagged roles exercised here:
|
|
* h1-h3 → H1-H3 (heading hierarchy)
|
|
* p → P (paragraph)
|
|
* blockquote → BlockQuote
|
|
* pre → Code
|
|
* ul / ol → L (list; li → LI > Lbl + LBody auto-generated)
|
|
* figure → Figure
|
|
* img[alt] → Figure + /Alt (alt text written to struct-elem dictionary)
|
|
* figcaption → Caption
|
|
* table → Table (tr → TR, th → TH, td → TD, caption → Caption)
|
|
* a → Link
|
|
*/
|
|
|
|
// NOTE: local file reads (images, fonts, attachments) are restricted to an allowlist of
|
|
// trusted paths that covers this package tree, so run the examples in place. To read assets
|
|
// from other locations, list them in the 'allowedPaths' entry of the fileOptions constructor
|
|
// parameter (see E047_remote_resources_security.php).
|
|
|
|
require __DIR__ . '/../vendor/autoload.php';
|
|
|
|
\define('K_PATH_FONTS', \realpath(__DIR__ . '/../vendor/tecnickcom/tc-lib-pdf-font/target/fonts'));
|
|
|
|
$pdf = new \Com\Tecnick\Pdf\Tcpdf(
|
|
unit: \Com\Tecnick\Pdf\Page\Unit::Millimeter,
|
|
isunicode: true,
|
|
subsetfont: false,
|
|
compress: true,
|
|
mode: \Com\Tecnick\Pdf\PdfConformance::Pdfua1,
|
|
);
|
|
$pdf->setCreator('tc-lib-pdf');
|
|
$pdf->setAuthor('Nicola Asuni');
|
|
$pdf->setTitle('PDF/UA-1 Auto-Tagged HTML');
|
|
$pdf->setSubject('tc-lib-pdf example: 016 — pdfua1 mode HTML tagging showcase');
|
|
$pdf->setKeywords('TCPDF tc-lib-pdf pdfua1 PDF/UA-1 ISO14289 tagged PDF accessibility HTML auto-tag');
|
|
$pdf->setPDFFilename('E016_pdfua1.pdf');
|
|
$pdf->setLanguage(code: 'en-US');
|
|
|
|
$font = $pdf->font->insert($pdf->pon, 'dejavusans', '', 10);
|
|
|
|
// PDF/UA requires every font to be embedded. <code>/<pre> default to the
|
|
// non-embedded standard-14 Courier, so register an embedded monospace font and
|
|
// select it for those elements.
|
|
$pdf->font->insert($pdf->pon, 'dejavusansmono', '', 10);
|
|
$pdf->setHTMLMonospaceFont('dejavusansmono');
|
|
|
|
$pdf->addPage();
|
|
$pdf->page->addContent($font['out']);
|
|
|
|
$imgPath = __DIR__ . '/images/tcpdf_logo.jpg';
|
|
|
|
$html =
|
|
'<h1>PDF/UA-1 — Auto-Tagged HTML Showcase</h1>'
|
|
. '<p>Mode: <strong>pdfua1</strong> (ISO 14289-1, PDF 1.7). This document'
|
|
. ' demonstrates every HTML element that <code>addHTMLCell()</code> auto-tags with a'
|
|
. ' PDF/UA-1 structure role. PDF/UA-1 is the original accessible-PDF standard: it mandates'
|
|
. ' a tagged structure tree, document language, <code>MarkInfo /Marked true</code>,'
|
|
. ' and <code>ViewerPreferences /DisplayDocTitle true</code>. All of these are written'
|
|
. ' automatically when the <em>pdfua1</em> mode is active.</p>'
|
|
. '<h2>1 — Heading and Paragraph Roles</h2>'
|
|
. '<h3>H3 Sub-heading</h3>'
|
|
. '<p>The <code>h1</code>-<code>h6</code> tags map to PDF roles <strong>H1-H6</strong>.'
|
|
. ' The <code>p</code> tag maps to <strong>P</strong>.'
|
|
. ' PDF/UA-1 requires that heading levels are not skipped: the library clamps each'
|
|
. ' heading to at most one level deeper than the previous heading to maintain a'
|
|
. ' well-formed outline that screen readers can navigate.</p>'
|
|
. '<h2>2 — Block Roles</h2>'
|
|
. '<blockquote>“Tagged PDF is the foundation of accessible PDF. Without a'
|
|
. ' well-formed structure tree, automated tools and assistive technologies cannot'
|
|
. ' reliably interpret document content.” — ISO 14289-1 rationale</blockquote>'
|
|
. '<p>The <code>blockquote</code> tag maps to <strong>BlockQuote</strong>.</p>'
|
|
. '<h2>3 — List Structure (L > LI > Lbl + LBody)</h2>'
|
|
. '<p>Both <code>ul</code> and <code>ol</code> map to the <strong>L</strong> role.'
|
|
. ' Each <code>li</code> auto-generates <strong>LI > {Lbl, LBody}</strong> children:</p>'
|
|
. '<ul>'
|
|
. '<li>Unordered item — <code>ul</code>/<code>li</code> tags produce L/LI structure</li>'
|
|
. '<li>The bullet character is placed in a <strong>Lbl</strong> child element</li>'
|
|
. '<li>Body text is wrapped in a <strong>LBody</strong> child element</li>'
|
|
. '</ul>'
|
|
. '<ol>'
|
|
. '<li>Ordered item — the number is auto-generated as the <strong>Lbl</strong></li>'
|
|
. '<li>Body text is again auto-wrapped in <strong>LBody</strong></li>'
|
|
. '<li>Nesting: L > LI > {Lbl, LBody}</li>'
|
|
. '</ol>'
|
|
. '<h2>4 — Figure, Image Alt-Text, and Caption</h2>'
|
|
. '<figure>'
|
|
. '<img src="'
|
|
. $imgPath
|
|
. '" alt="TCPDF logo: blue text on white background" width="89" height="30" />'
|
|
. '<figcaption>Figure 1 — TCPDF logo. The <code>alt</code> attribute becomes'
|
|
. ' <strong>/Alt</strong> in the Figure structure-element dictionary.'
|
|
. ' PDF/UA-1 requires every Figure to carry an /Alt or /ActualText entry so'
|
|
. ' screen readers can describe non-text content. The <code>figcaption</code> tag'
|
|
. ' maps to <strong>Caption</strong>.</figcaption>'
|
|
. '</figure>'
|
|
. '<h2>5 — Table Structure (Table > TR > TH/TD)</h2>'
|
|
. '<table border="1" cellspacing="0" cellpadding="3">'
|
|
. '<caption>Table 1 — HTML tags and their PDF/UA-1 structure roles</caption>'
|
|
. '<tr><th>HTML tag</th><th>PDF structure role</th><th>Category</th></tr>'
|
|
. '<tr><td>h1–h6</td><td>H1–H6</td><td>Heading</td></tr>'
|
|
. '<tr><td>p</td><td>P</td><td>Body</td></tr>'
|
|
. '<tr><td>blockquote</td><td>BlockQuote</td><td>Body</td></tr>'
|
|
. '<tr><td>pre</td><td>Code</td><td>Body</td></tr>'
|
|
. '<tr><td>ul, ol</td><td>L</td><td>List</td></tr>'
|
|
. '<tr><td>li</td><td>LI + Lbl + LBody</td><td>List</td></tr>'
|
|
. '<tr><td>figure</td><td>Figure</td><td>Illustration</td></tr>'
|
|
. '<tr><td>img (with alt)</td><td>Figure + /Alt</td><td>Illustration</td></tr>'
|
|
. '<tr><td>figcaption, caption</td><td>Caption</td><td>Illustration</td></tr>'
|
|
. '<tr><td>table</td><td>Table</td><td>Table</td></tr>'
|
|
. '<tr><td>tr</td><td>TR</td><td>Table</td></tr>'
|
|
. '<tr><td>td</td><td>TD</td><td>Table</td></tr>'
|
|
. '<tr><td>th</td><td>TH</td><td>Table</td></tr>'
|
|
. '<tr><td>a</td><td>Link</td><td>Inline</td></tr>'
|
|
. '</table>'
|
|
. '<h2>6 — Hyperlink (Link Role)</h2>'
|
|
. '<p>This sentence contains a'
|
|
. ' <a href="https://github.com/tecnickcom/tc-lib-pdf" style="text-decoration:none;">hyperlink to the tc-lib-pdf repository</a>;'
|
|
. ' the <code>a</code> element is tagged with the <strong>Link</strong> structure role'
|
|
. ' automatically. PDF/UA-1 requires that link annotations have an accessible name,'
|
|
. ' which the library derives from the link text in the structure tree.</p>'
|
|
. '<h2>7 — Rules, Spans and Empty Cells</h2>'
|
|
. '<p>A horizontal rule carries no semantics, so it is emitted as an <strong>Artifact</strong>'
|
|
. ' rather than left as untagged content (PDF/UA-1 7.1):</p>'
|
|
. '<hr>'
|
|
. '<p>Cell <code>colspan</code>/<code>rowspan</code> are recorded on the cell structure'
|
|
. ' element as integer <strong>/ColSpan</strong> and <strong>/RowSpan</strong> attributes,'
|
|
. ' and an empty cell is kept in the tree so the row keeps its full column count (7.2):</p>'
|
|
. '<table border="1" cellspacing="0" cellpadding="3">'
|
|
. '<tr><th>Col A</th><th>Col B</th><th>Col C</th></tr>'
|
|
. '<tr><td colspan="2">Spans columns A and B</td><td>C</td></tr>'
|
|
. '<tr><td rowspan="2">Spans rows</td><td>B2</td><td>C2</td></tr>'
|
|
. '<tr><td>B3</td><td></td></tr>'
|
|
. '</table>';
|
|
|
|
// A long table that breaks across pages: the repeated header on each continuation
|
|
// page is an Artifact, while the single Table structure element keeps all its rows.
|
|
$html .=
|
|
'<h2>8 — Page-Spanning Table</h2>'
|
|
. '<table border="1" cellspacing="0" cellpadding="2">'
|
|
. '<thead><tr><th>#</th><th>Description</th></tr></thead>';
|
|
for ($row = 1; $row <= 60; ++$row) {
|
|
$html .= '<tr><td>' . $row . '</td><td>Continuation row ' . $row . '</td></tr>';
|
|
}
|
|
|
|
$html .= '</table>';
|
|
|
|
$pdf->addHTMLCell(html: $html, posx: 15, posy: 20, width: 180);
|
|
|
|
$rawpdf = $pdf->getOutPDFString();
|
|
$pdf->renderPDF(rawpdf: $rawpdf);
|