Check for Transparency
This demo checks the resources of all pages and form XObjects for elements which will invoke transparency.
This demo does not checks whether these resources are used or not.
PHP
<?php
use com\setasign\SetaPDF\Demos\Inspector\TransparencyInspector;
// load and register the autoload function
require_once '../../../../../bootstrap.php';
// prepare some files
$files = glob($assetsDirectory . '/pdfs/misc/*.pdf');
$files[] = $assetsDirectory . '/pdfs/Brand-Guide.pdf';
$path = displayFiles($files);
// require the text processor class
require_once $classesDirectory . '/Inspector/TransparencyInspector.php';
$document = \SetaPDF_Core_Document::loadByFilename($path);
$inspector = new TransparencyInspector($document);
$transparencyElements = $inspector->process();
foreach ($transparencyElements as $element) {
echo 'Type: ' . $element['type'] . '<br />';
echo 'Info: ' . $element['info'] . '<br />';
echo 'Location: ' . $element['location'] . '<br />';
echo 'Data (class name): ' . get_class($element['data']) . '<br />';
echo "<br />";
}
if (count($transparencyElements) === 0) {
echo 'No transparency found.';
}
PHP
<?php
namespace com\setasign\SetaPDF\Demos\Inspector;
/**
* Class TransparencyInspector
*/
class TransparencyInspector
{
/**
* @var \SetaPDF_Core_Document
*/
protected $_document;
/**
* Information about the currently processed "location"
*
* @var string
*/
protected $_currentLocation = [];
/**
* Found elements
*
* @var array
*/
protected $_elements = [];
/**
* The constructor
*
* @param \SetaPDF_Core_Document $document
*/
public function __construct(\SetaPDF_Core_Document $document)
{
$this->_document = $document;
}
/**
* Get elements that invoke transparency behavior in the document.
*
* @return array
*/
public function process()
{
$this->_elements = [];
$pages = $this->_document->getCatalog()->getPages();
for ($pageNo = 1, $pageCount = $pages->count(); $pageNo <= $pageCount; $pageNo++) {
$page = $pages->getPage($pageNo);
$this->_currentLocation = ['Page ' . $pageNo];
$xObjects = $page->getCanvas()->getResources(true, false, \SetaPDF_Core_Resource::TYPE_X_OBJECT);
if ($xObjects) {
$this->_processXObjects($xObjects);
}
$graphicStates = $page->getCanvas()->getResources(true, false, \SetaPDF_Core_Resource::TYPE_EXT_G_STATE);
if ($graphicStates) {
$this->_processGraphicStates($graphicStates);
}
}
return $this->_elements;
}
/**
* Check graphic states for transparency.
*
* @param \SetaPDF_Core_Type_Dictionary $graphicStates
*/
protected function _processGraphicStates(\SetaPDF_Core_Type_Dictionary $graphicStates)
{
$root = $this->_currentLocation;
foreach ($graphicStates AS $name => $graphicState) {
$this->_currentLocation = $root;
$this->_currentLocation[] = 'GraphicState (' . $name . ')';
$dictionary = $graphicState->ensure();
if (!$dictionary instanceof \SetaPDF_Core_Type_Dictionary) {
continue;
}
if (isset($dictionary['SMask']) && $dictionary->getValue('SMask')->ensure()->getValue() !== 'None') {
$this->_addTransparentElement('GraphicState', $dictionary, 'Graphic state with SMask entry');
continue;
}
if (isset($dictionary['CA']) && $dictionary->getValue('CA')->getValue() != 1.0) {
$this->_addTransparentElement(
'GraphicState',
$dictionary,
'Graphic state with "CA" value of ' . sprintf('%.5F', $dictionary->getValue('CA')->getValue())
);
}
if (isset($dictionary['ca']) && $dictionary->getValue('ca')->getValue() != 1.0) {
$this->_addTransparentElement(
'GraphicState',
$dictionary,
'Graphic state with "ca" value of ' . sprintf('%.5F', $dictionary->getValue('CA')->getValue())
);
}
}
$this->_currentLocation = $root;
}
/**
* Check XObjects for transparency.
*
* @param \SetaPDF_Core_Type_Dictionary $xObjects
* @throws \SetaPDF_Exception_NotImplemented
*/
protected function _processXObjects(\SetaPDF_Core_Type_Dictionary $xObjects)
{
$root = $this->_currentLocation;
foreach ($xObjects AS $name => $xObject) {
$this->_currentLocation = $root;
$this->_currentLocation[] = 'XObject (' . $name . ')';
$xObject = \SetaPDF_Core_XObject::get($xObject);
// images
if ($xObject instanceof \SetaPDF_Core_XObject_Image) {
$dictionary = $xObject->getIndirectObject()->ensure()->getValue();
/* An image XObject may contain its own soft-mask image in the form of a subsidiary image XObject in the
* SMask entry of the image dictionary (see “Image Dictionaries”). This mask, if present, shall override
* any explicit or colour key mask specified by the image dictionary’s Mask entry. Either form of mask
* in the image dictionary shall override the current soft mask in the graphics state.
*/
if (isset($dictionary['SMask'])) {
$this->_addTransparentElement('Image', $xObject, 'Image with SMask entry');
continue;
}
/* An image XObject that has a JPXDecode filter as its data source may specify an SMaskInData entry,
* indicating that the soft mask is embedded in the data stream (see “JPXDecode Filter”).
*/
if ($dictionary->getValue('Filter')->getValue() === 'JPXDecode') {
if (isset($dictionary['SMaskInData']) && $dictionary->getValue('SMaskInData')->getValue() != 0) {
$this->_addTransparentElement(
'Image',
$xObject,
'Image with JPXDecode filter and SMaskInData entry'
);
continue;
}
}
// form XObjects
} elseif ($xObject instanceof \SetaPDF_Core_XObject_Form) {
$_xObjects = $xObject->getCanvas()->getResources(true, false, \SetaPDF_Core_Resource::TYPE_X_OBJECT);
if ($_xObjects) {
$this->_processXObjects($_xObjects);
}
$graphicStates = $xObject->getCanvas()->getResources(true, false, \SetaPDF_Core_Resource::TYPE_EXT_G_STATE);
if ($graphicStates) {
$this->_processGraphicStates($graphicStates);
}
}
}
}
protected function _addTransparentElement($type, $data, $info)
{
$this->_elements[] = [
'type' => $type,
'data' => $data,
'info' => $info,
'location' => join(', ', $this->_currentLocation)
];
}
}