/**
* Object constructor.
*
* If resource is not a Zend_Pdf_Element object, then stream object with specified value is
* generated.
*
* @param Zend_Pdf_Element|string $resource
*/
public function __construct($resource)
{
$this->_processedFacories = array();
$this->_objectFactory = new Zend_Pdf_ElementFactory(1);
if ($resource instanceof Zend_Pdf_Element) {
$this->_resource = $this->_objectFactory->newObject($resource);
} else {
$this->_resource = $this->_objectFactory->newStreamObject($resource);
}
}
/**
* Dump current drawing instructions into the content stream.
*
* @todo Don't forget to close all current graphics operations (like path drawing)
*
* @throws Zend_Pdf_Exception
*/
public function flush()
{
if ($this->_saveCount != 0) {
throw new Zend_Pdf_Exception('Saved graphics state is not restored');
}
if ($this->_contents == '') {
return;
}
if ($this->_pageDictionary->Contents->getType() != Zend_Pdf_Element::TYPE_ARRAY) {
/**
* It's a stream object.
* Prepare Contents page attribute for update.
*/
$this->_pageDictionary->touch();
$currentPageContents = $this->_pageDictionary->Contents;
$this->_pageDictionary->Contents = new Zend_Pdf_Element_Array();
$this->_pageDictionary->Contents->items[] = $currentPageContents;
} else {
$this->_pageDictionary->Contents->touch();
}
$this->_pageDictionary->Contents->items[] = $this->_objFactory->newStreamObject($this->_contents);
$this->_contents == '';
}
/**
* Object constructor
*
* @param string $imageFileName
* @throws Zend_Pdf_Exception
* @todo Add compression conversions to support compression strategys other than PNG_COMPRESSION_DEFAULT_STRATEGY.
* @todo Add pre-compression filtering.
* @todo Add interlaced image handling.
* @todo Add support for 16-bit images. Requires PDF version bump to 1.5 at least.
* @todo Add processing for all PNG chunks defined in the spec. gAMA etc.
* @todo Fix tRNS chunk support for Indexed Images to a SMask.
*/
public function __construct($imageFileName)
{
if (($imageFile = @fopen($imageFileName, 'rb')) === false) {
throw new Zend_Pdf_Exception("Can not open '{$imageFileName}' file for reading.");
}
parent::__construct();
//Check if the file is a PNG
fseek($imageFile, 1, SEEK_CUR);
//First signature byte (%)
if ('PNG' != fread($imageFile, 3)) {
throw new Zend_Pdf_Exception('Image is not a PNG');
}
fseek($imageFile, 12, SEEK_CUR);
//Signature bytes (Includes the IHDR chunk) IHDR processed linerarly because it doesnt contain a variable chunk length
$wtmp = unpack('Ni', fread($imageFile, 4));
//Unpack a 4-Byte Long
$width = $wtmp['i'];
$htmp = unpack('Ni', fread($imageFile, 4));
$height = $htmp['i'];
$bits = ord(fread($imageFile, 1));
//Higher than 8 bit depths are only supported in later versions of PDF.
$color = ord(fread($imageFile, 1));
$compression = ord(fread($imageFile, 1));
$prefilter = ord(fread($imageFile, 1));
if (($interlacing = ord(fread($imageFile, 1))) != Zend_Pdf_Image_Png::PNG_INTERLACING_DISABLED) {
throw new Zend_Pdf_Exception("Only non-interlaced images are currently supported.");
}
$this->_width = $width;
$this->_height = $height;
$this->_imageProperties = array();
$this->_imageProperties['bitDepth'] = $bits;
$this->_imageProperties['pngColorType'] = $color;
$this->_imageProperties['pngFilterType'] = $prefilter;
$this->_imageProperties['pngCompressionType'] = $compression;
$this->_imageProperties['pngInterlacingType'] = $interlacing;
fseek($imageFile, 4, SEEK_CUR);
//4 Byte Ending Sequence
$imageData = '';
/*
* The following loop processes PNG chunks. 4 Byte Longs are packed first give the chunk length
* followed by the chunk signature, a four byte code. IDAT and IEND are manditory in any PNG.
*/
while (($chunkLengthBytes = fread($imageFile, 4)) !== false) {
$chunkLengthtmp = unpack('Ni', $chunkLengthBytes);
$chunkLength = $chunkLengthtmp['i'];
$chunkType = fread($imageFile, 4);
switch ($chunkType) {
case 'IDAT':
//Image Data
/*
* Reads the actual image data from the PNG file. Since we know at this point that the compression
* strategy is the default strategy, we also know that this data is Zip compressed. We will either copy
* the data directly to the PDF and provide the correct FlateDecode predictor, or decompress the data
* decode the filters and output the data as a raw pixel map.
*/
$imageData .= fread($imageFile, $chunkLength);
fseek($imageFile, 4, SEEK_CUR);
break;
case 'PLTE':
//Palette
$paletteData = fread($imageFile, $chunkLength);
fseek($imageFile, 4, SEEK_CUR);
break;
case 'tRNS':
//Basic (non-alpha channel) transparency.
$trnsData = fread($imageFile, $chunkLength);
switch ($color) {
case Zend_Pdf_Image_Png::PNG_CHANNEL_GRAY:
$baseColor = ord(substr($trnsData, 1, 1));
$transparencyData = array(new Zend_Pdf_Element_Numeric($baseColor), new Zend_Pdf_Element_Numeric($baseColor));
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_RGB:
$red = ord(substr($trnsData, 1, 1));
$green = ord(substr($trnsData, 3, 1));
$blue = ord(substr($trnsData, 5, 1));
$transparencyData = array(new Zend_Pdf_Element_Numeric($red), new Zend_Pdf_Element_Numeric($red), new Zend_Pdf_Element_Numeric($green), new Zend_Pdf_Element_Numeric($green), new Zend_Pdf_Element_Numeric($blue), new Zend_Pdf_Element_Numeric($blue));
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_INDEXED:
//Find the first transparent color in the index, we will mask that. (This is a bit of a hack. This should be a SMask and mask all entries values).
if (($trnsIdx = strpos($trnsData, chr(0))) !== false) {
$transparencyData = array(new Zend_Pdf_Element_Numeric($trnsIdx), new Zend_Pdf_Element_Numeric($trnsIdx));
}
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_GRAY_ALPHA:
// Fall through to the next case
// Fall through to the next case
case Zend_Pdf_Image_Png::PNG_CHANNEL_RGB_ALPHA:
throw new Zend_Pdf_Exception("tRNS chunk illegal for Alpha Channel Images");
break;
}
fseek($imageFile, 4, SEEK_CUR);
//4 Byte Ending Sequence
break;
case 'IEND':
break 2;
//End the loop too
//End the loop too
default:
fseek($imageFile, $chunkLength + 4, SEEK_CUR);
//Skip the section
break;
}
}
fclose($imageFile);
$compressed = true;
$imageDataTmp = '';
$smaskData = '';
switch ($color) {
case Zend_Pdf_Image_Png::PNG_CHANNEL_RGB:
$colorSpace = new Zend_Pdf_Element_Name('DeviceRGB');
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_GRAY:
$colorSpace = new Zend_Pdf_Element_Name('DeviceGray');
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_INDEXED:
if (empty($paletteData)) {
throw new Zend_Pdf_Exception("PNG Corruption: No palette data read for indexed type PNG.");
}
$colorSpace = new Zend_Pdf_Element_Array();
$colorSpace->items[] = new Zend_Pdf_Element_Name('Indexed');
$colorSpace->items[] = new Zend_Pdf_Element_Name('DeviceRGB');
$colorSpace->items[] = new Zend_Pdf_Element_Numeric(strlen($paletteData) / 3 - 1);
$paletteObject = $this->_objectFactory->newObject(new Zend_Pdf_Element_String_Binary($paletteData));
$colorSpace->items[] = $paletteObject;
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_GRAY_ALPHA:
/*
* To decode PNG's with alpha data we must create two images from one. One image will contain the Gray data
* the other will contain the Gray transparency overlay data. The former will become the object data and the latter
* will become the Shadow Mask (SMask).
*/
if ($bits > 8) {
throw new Zend_Pdf_Exception("Alpha PNGs with bit depth > 8 are not yet supported");
}
$colorSpace = new Zend_Pdf_Element_Name('DeviceGray');
$decodingObjFactory = new Zend_Pdf_ElementFactory(1);
$decodingStream = $decodingObjFactory->newStreamObject($imageData);
$decodingStream->dictionary->Filter = new Zend_Pdf_Element_Name('FlateDecode');
$decodingStream->dictionary->DecodeParms = new Zend_Pdf_Element_Dictionary();
$decodingStream->dictionary->DecodeParms->Predictor = new Zend_Pdf_Element_Numeric(15);
$decodingStream->dictionary->DecodeParms->Columns = new Zend_Pdf_Element_Numeric($width);
$decodingStream->dictionary->DecodeParms->Colors = new Zend_Pdf_Element_Numeric(2);
//GreyAlpha
$decodingStream->dictionary->DecodeParms->BitsPerComponent = new Zend_Pdf_Element_Numeric($bits);
$decodingStream->skipFilters();
$pngDataRawDecoded = $decodingStream->value;
//Iterate every pixel and copy out gray data and alpha channel (this will be slow)
for ($pixel = 0, $pixelcount = $width * $height; $pixel < $pixelcount; $pixel++) {
$imageDataTmp .= $pngDataRawDecoded[$pixel * 2];
$smaskData .= $pngDataRawDecoded[$pixel * 2 + 1];
}
$compressed = false;
$imageData = $imageDataTmp;
//Overwrite image data with the gray channel without alpha
break;
case Zend_Pdf_Image_Png::PNG_CHANNEL_RGB_ALPHA:
/*
* To decode PNG's with alpha data we must create two images from one. One image will contain the RGB data
* the other will contain the Gray transparency overlay data. The former will become the object data and the latter
* will become the Shadow Mask (SMask).
*/
if ($bits > 8) {
throw new Zend_Pdf_Exception("Alpha PNGs with bit depth > 8 are not yet supported");
}
$colorSpace = new Zend_Pdf_Element_Name('DeviceRGB');
$decodingObjFactory = new Zend_Pdf_ElementFactory(1);
$decodingStream = $decodingObjFactory->newStreamObject($imageData);
$decodingStream->dictionary->Filter = new Zend_Pdf_Element_Name('FlateDecode');
$decodingStream->dictionary->DecodeParms = new Zend_Pdf_Element_Dictionary();
$decodingStream->dictionary->DecodeParms->Predictor = new Zend_Pdf_Element_Numeric(15);
$decodingStream->dictionary->DecodeParms->Columns = new Zend_Pdf_Element_Numeric($width);
$decodingStream->dictionary->DecodeParms->Colors = new Zend_Pdf_Element_Numeric(4);
//RGBA
$decodingStream->dictionary->DecodeParms->BitsPerComponent = new Zend_Pdf_Element_Numeric($bits);
$decodingStream->skipFilters();
$pngDataRawDecoded = $decodingStream->value;
//Iterate every pixel and copy out rgb data and alpha channel (this will be slow)
for ($pixel = 0, $pixelcount = $width * $height; $pixel < $pixelcount; $pixel++) {
$imageDataTmp .= $pngDataRawDecoded[$pixel * 4 + 0] . $pngDataRawDecoded[$pixel * 4 + 1] . $pngDataRawDecoded[$pixel * 4 + 2];
$smaskData .= $pngDataRawDecoded[$pixel * 4 + 3];
}
$compressed = false;
$imageData = $imageDataTmp;
//Overwrite image data with the RGB channel without alpha
break;
default:
throw new Zend_Pdf_Exception("PNG Corruption: Invalid color space.");
}
if (empty($imageData)) {
throw new Zend_Pdf_Exception("Corrupt PNG Image. Mandatory IDAT chunk not found.");
}
$imageDictionary = $this->_resource->dictionary;
if (!empty($smaskData)) {
/*
* Includes the Alpha transparency data as a Gray Image, then assigns the image as the Shadow Mask for the main image data.
*/
$smaskStream = $this->_objectFactory->newStreamObject($smaskData);
$smaskStream->dictionary->Type = new Zend_Pdf_Element_Name('XObject');
$smaskStream->dictionary->Subtype = new Zend_Pdf_Element_Name('Image');
$smaskStream->dictionary->Width = new Zend_Pdf_Element_Numeric($width);
$smaskStream->dictionary->Height = new Zend_Pdf_Element_Numeric($height);
$smaskStream->dictionary->ColorSpace = new Zend_Pdf_Element_Name('DeviceGray');
$smaskStream->dictionary->BitsPerComponent = new Zend_Pdf_Element_Numeric($bits);
$imageDictionary->SMask = $smaskStream;
// Encode stream with FlateDecode filter
$smaskStreamDecodeParms = array();
$smaskStreamDecodeParms['Predictor'] = new Zend_Pdf_Element_Numeric(15);
$smaskStreamDecodeParms['Columns'] = new Zend_Pdf_Element_Numeric($width);
$smaskStreamDecodeParms['Colors'] = new Zend_Pdf_Element_Numeric(1);
$smaskStreamDecodeParms['BitsPerComponent'] = new Zend_Pdf_Element_Numeric(8);
$smaskStream->dictionary->DecodeParms = new Zend_Pdf_Element_Dictionary($smaskStreamDecodeParms);
$smaskStream->dictionary->Filter = new Zend_Pdf_Element_Name('FlateDecode');
}
if (!empty($transparencyData)) {
//This is experimental and not properly tested.
$imageDictionary->Mask = new Zend_Pdf_Element_Array($transparencyData);
}
$imageDictionary->Width = new Zend_Pdf_Element_Numeric($width);
$imageDictionary->Height = new Zend_Pdf_Element_Numeric($height);
$imageDictionary->ColorSpace = $colorSpace;
$imageDictionary->BitsPerComponent = new Zend_Pdf_Element_Numeric($bits);
$imageDictionary->Filter = new Zend_Pdf_Element_Name('FlateDecode');
$decodeParms = array();
$decodeParms['Predictor'] = new Zend_Pdf_Element_Numeric(15);
// Optimal prediction
$decodeParms['Columns'] = new Zend_Pdf_Element_Numeric($width);
$decodeParms['Colors'] = new Zend_Pdf_Element_Numeric($color == Zend_Pdf_Image_Png::PNG_CHANNEL_RGB || $color == Zend_Pdf_Image_Png::PNG_CHANNEL_RGB_ALPHA ? 3 : 1);
$decodeParms['BitsPerComponent'] = new Zend_Pdf_Element_Numeric($bits);
$imageDictionary->DecodeParms = new Zend_Pdf_Element_Dictionary($decodeParms);
//Include only the image IDAT section data.
$this->_resource->value = $imageData;
//Skip double compression
if ($compressed) {
$this->_resource->skipFilters();
}
}
