Get Images Size and Resolution
This demo extracts size and resolution of images used in a PDF document.
Furthermore it allows you to mark the found images of a page in the document.
PHP
<?php
use com\setasign\SetaPDF\Demos\ContentStreamProcessor\ImageProcessor;
// load and register the autoload function
require_once '../../../../../bootstrap.php';
// prepare some files
$files = glob($assetsDirectory . '/pdfs/lenstown/products/*.pdf');
$files[] = $assetsDirectory . '/pdfs/Brand-Guide.pdf';
$files[] = $assetsDirectory . '/pdfs/Fact-Sheet-form.pdf';
$files[] = $assetsDirectory . '/pdfs/misc/Handwritten-Signature.pdf';
$path = displayFiles($files);
require_once $classesDirectory . '/ContentStreamProcessor/ImageProcessor.php';
// display the information about the found images
if (!isset($_GET['p'])) {
// load a document instance
$document = \SetaPDF_Core_Document::loadByFilename($path);
// get access to the pages object
$pages = $document->getCatalog()->getPages();
// walk through the pages
for ($pageNo = 1, $pageCount = $pages->count(); $pageNo <= $pageCount; $pageNo++) {
$page = $pages->getPage($pageNo);
// process the canvas of the page
$imageProcessor = new ImageProcessor($page->getCanvas(), ($page->getRotation() / 90) % 2 > 0);
$images = $imageProcessor->process();
echo '<pre>';
if (count($images)) {
echo '<a href="?f=' . urlencode($_GET['f']) . '&p=' . $pageNo . '#page=' . $pageNo . '">Found '
. count($images) . ' images on page #' . $pageNo . "</a>.\n";
} else {
echo 'Found no images on page #' . $pageNo . ".\n";
}
foreach ($images as $no => $image) {
echo ' Image #' . ($no + 1) . "\n";
echo ' ll => ' . $image['ll']->getX() . ' / ' . $image['ll']->getY() . "\n";
echo ' ul => ' . $image['ul']->getX() . ' / ' . $image['ul']->getY() . "\n";
echo ' ur => ' . $image['ur']->getX() . ' / ' . $image['ur']->getY() . "\n";
echo ' lr => ' . $image['lr']->getX() . ' / ' . $image['lr']->getY() . "\n";
echo ' width => ' . $image['width'] . "\n";
echo ' height => ' . $image['height'] . "\n";
echo ' resolutionX => ' . $image['resolutionX'] . "\n";
echo ' resolutionY => ' . $image['resolutionY'] . "\n";
echo ' pixelWidth => ' . $image['pixelWidth'] . "\n";
echo ' pixelHeight => ' . $image['pixelHeight'] . "\n";
echo "\n";
}
echo '</pre>';
echo '<br/>';
}
// mark the images of a specific page and output the resulting PDF
} else {
// let's create a writer and document instance
$writer = new \SetaPDF_Core_Writer_Http('marked.pdf', true);
$document = \SetaPDF_Core_Document::loadByFilename($path, $writer);
// get access to the pages object
$pages = $document->getCatalog()->getPages();
// get the page by the given parameter
$page = $pages->getPage($_GET['p']);
// set an open action, so that the page is shown when opened (requires support of the reader application)
$dest = \SetaPDF_Core_Document_Destination::createByPage($page);
$document->getCatalog()->setOpenAction(new \SetaPDF_Core_Document_Action_GoTo($dest));
// get access to the pages canvas
$canvas = $page->getCanvas();
// let's get the image information
$imageProcessor = new ImageProcessor($canvas, ($page->getRotation() / 90) % 2 > 0);
$images = $imageProcessor->process();
// ensure a fresh graphic state
$page->getContents()->encapsulateExistingContentInGraphicState();
// draw rectangles around the found images
$canvas->saveGraphicState();
$canvas->path()->setLineWidth(2);
$canvas->setStrokingColor('#ff00ff');
foreach ($images as $image) {
$canvas->draw()
->rect($image['ll']->getX(), $image['ll']->getY(), $image['width'], $image['height']);
}
$canvas->restoreGraphicState();
// send the document to the client
$document->save()->finish();
}
PHP
<?php
namespace com\setasign\SetaPDF\Demos\ContentStreamProcessor;
/**
* Class ImageProcessor
*/
class ImageProcessor
{
/**
* The content stream.
*
* @var string
*/
protected $_canvas;
/**
* The graphic state.
*
* @var \SetaPDF_Core_Canvas_GraphicState
*/
protected $_graphicState;
/**
* The content parser instance.
*
* @var \SetaPDF_Core_Parser_Content
*/
protected $_contentParser;
/**
* The result data.
*
* @var array
*/
protected $_result = [];
/**
* Switch the width and height values.
*
* @var bool
*/
protected $_switchWidthAndHeight = false;
/**
* The constructor.
*
* The parameter are the content stream and its resources dictionary.
*
* @param \SetaPDF_Core_Canvas $canvas
* @param boolean $switchWidthAndHeight
* @param \SetaPDF_Core_Canvas_GraphicState|null $graphicState
*/
public function __construct(
\SetaPDF_Core_Canvas $canvas,
$switchWidthAndHeight,
\SetaPDF_Core_Canvas_GraphicState $graphicState = null
)
{
$this->_canvas = $canvas;
$this->_switchWidthAndHeight = $switchWidthAndHeight;
$this->_graphicState = $graphicState === null ? new \SetaPDF_Core_Canvas_GraphicState() : $graphicState;
}
/**
* Get the graphic state.
*
* @return \SetaPDF_Core_Canvas_GraphicState
*/
public function getGraphicState()
{
return $this->_graphicState;
}
/**
* Process the content stream and return the resolved data.
*
* @return array
*/
public function process()
{
$parser = $this->_getContentParser();
$parser->process();
return $this->_result;
}
/**
* A method to receive the content parser instance.
*
* @return \SetaPDF_Core_Parser_Content
*/
protected function _getContentParser()
{
if ($this->_contentParser === null) {
try {
$stream = $this->_canvas->getStream();
} catch (\SetaPDF_Core_Filter_Exception $e) {
// if a stream cannot be unfiltered, we ignore it
$stream = '';
}
$this->_contentParser = new \SetaPDF_Core_Parser_Content($stream);
$this->_contentParser->registerOperator(['q', 'Q'], [$this, '_onGraphicStateChange']);
$this->_contentParser->registerOperator('cm', [$this, '_onCurrentTransformationMatrix']);
$this->_contentParser->registerOperator('Do', [$this, '_onFormXObject']);
$this->_contentParser->registerOperator('ID', [$this, '_onInlineImageData']);
}
return $this->_contentParser;
}
/**
* Callback for inline image data operator
*
* @param array $arguments
* @param string $operator
*/
public function _onInlineImageData($arguments, $operator)
{
$data = [];
for ($i = 0, $c = count($arguments); $i < $c; $i += 2) {
$data[$arguments[$i]->getValue()] = $arguments[$i + 1];
}
if (!(isset($data['W']) || isset($data['Width'])) || !(isset($data['H']) || isset($data['Height']))) {
return true;
}
$pixelWidth = isset($data['W']) ? $data['W']->getValue() : $data['Width']->getValue();
$pixelHeight = isset($data['H']) ? $data['H']->getValue() : $data['Height']->getValue();
$this->_result[] = $this->_getNewResult($pixelWidth, $pixelHeight);
$parser = $this->_contentParser->getParser();
$reader = $parser->getReader();
$pos = $reader->getPos();
$offset = $reader->getOffset();
while (
(\preg_match(
'/EI[\x00\x09\x0A\x0C\x0D\x20]/',
$reader->getBuffer(),
$m,
PREG_OFFSET_CAPTURE
)) === 0
) {
if ($reader->increaseLength(1000) === false) {
return false;
}
}
$parser->reset($pos + $offset + $m[0][1] + strlen($m[0][0]));
}
/**
* Callback for the content parser which is called if a graphic state token (q/Q) is found.
*
* @param array $arguments
* @param string $operator
*/
public function _onGraphicStateChange($arguments, $operator)
{
if ($operator === 'q') {
$this->getGraphicState()->save();
} else {
$this->getGraphicState()->restore();
}
}
/**
* Callback for the content parser which is called if a "cm" token is found.
*
* @param array $arguments
* @param string $operator
*/
public function _onCurrentTransformationMatrix($arguments, $operator)
{
$this->getGraphicState()->addCurrentTransformationMatrix(
$arguments[0]->getValue(), $arguments[1]->getValue(),
$arguments[2]->getValue(), $arguments[3]->getValue(),
$arguments[4]->getValue(), $arguments[5]->getValue()
);
}
/**
* Callback for the content parser which is called if a "Do" operator/token is found.
*
* @param array $arguments
*
* @throws \SetaPDF_Exception_NotImplemented
*/
public function _onFormXObject($arguments)
{
$xObjects = $this->_canvas->getResources(true, false, \SetaPDF_Core_Resource::TYPE_X_OBJECT);
if ($xObjects === null) {
return;
}
$xObjects = $xObjects->ensure();
$xObject = $xObjects->getValue($arguments[0]->getValue());
if (!($xObject instanceof \SetaPDF_Core_Type_IndirectReference)) {
return;
}
$xObjectReference = $xObject;
$xObject = \SetaPDF_Core_XObject::get($xObject);
if ($xObject instanceof \SetaPDF_Core_XObject_Form) {
/* In that case we need to create a new instance of the processor and process
* the form xobjects stream.
*/
$gs = $this->getGraphicState();
$gs->save();
$dict = $xObject->getIndirectObject()->ensure()->getValue();
$matrix = $dict->getValue('Matrix');
if ($matrix) {
$matrix = $matrix->ensure()->toPhp();
$gs->addCurrentTransformationMatrix(
$matrix[0], $matrix[1], $matrix[2], $matrix[3], $matrix[4], $matrix[5]
);
}
$processor = new self($xObject->getCanvas(), $this->_switchWidthAndHeight, $gs);
foreach ($processor->process() AS $image) {
$this->_result[] = $image;
}
$gs->restore();
} else {
$newResult = $this->_getNewResult($xObject->getWidth(), $xObject->getHeight());
$newResult['objectReference'] = $xObjectReference;
$this->_result[] = $newResult;
}
}
/**
* Helper method to create a result entry.
*
* @param numeric $pixelWidth
* @param numeric $pixelHeight
* @return array
*/
protected function _getNewResult($pixelWidth, $pixelHeight)
{
// we have an image object, calculate it's outer points in user space
$gs = $this->getGraphicState();
$ll = $gs->toUserSpace(new \SetaPDF_Core_Geometry_Vector(0, 0, 1));
$ul = $gs->toUserSpace(new \SetaPDF_Core_Geometry_Vector(0, 1, 1));
$ur = $gs->toUserSpace(new \SetaPDF_Core_Geometry_Vector(1, 1, 1));
$lr = $gs->toUserSpace(new \SetaPDF_Core_Geometry_Vector(1, 0, 1));
// ...and match some further information
$width = \abs($this->_switchWidthAndHeight ? $ur->subtract($ll)->getY() : $ur->subtract($ll)->getX());
$height = \abs($this->_switchWidthAndHeight ? $ur->subtract($ll)->getX() : $ur->subtract($ll)->getY());
return [
'll' => $ll->toPoint(),
'ul' => $ul->toPoint(),
'ur' => $ur->toPoint(),
'lr' => $lr->toPoint(),
'width' => $width,
'height' => $height,
'resolutionX' => $pixelWidth / $width * 72,
'resolutionY' => $pixelHeight / $height * 72,
'pixelWidth' => $pixelWidth,
'pixelHeight' => $pixelHeight
];
}
}