web/Zend/Pdf/Resource/Image/Png.php
changeset 0 4eba9c11703f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/Zend/Pdf/Resource/Image/Png.php	Mon Dec 13 18:29:26 2010 +0100
@@ -0,0 +1,380 @@
+<?php
+/**
+ * Zend Framework
+ *
+ * LICENSE
+ *
+ * This source file is subject to the new BSD license that is bundled
+ * with this package in the file LICENSE.txt.
+ * It is also available through the world-wide-web at this URL:
+ * http://framework.zend.com/license/new-bsd
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@zend.com so we can send you a copy immediately.
+ *
+ * @category   Zend
+ * @package    Zend_Pdf
+ * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ * @version    $Id: Png.php 23395 2010-11-19 15:30:47Z alexander $
+ */
+
+
+/** Internally used classes */
+require_once 'Zend/Pdf/Element/Array.php';
+require_once 'Zend/Pdf/Element/Dictionary.php';
+require_once 'Zend/Pdf/Element/Name.php';
+require_once 'Zend/Pdf/Element/Numeric.php';
+require_once 'Zend/Pdf/Element/String/Binary.php';
+
+
+/** Zend_Pdf_Resource_Image */
+require_once 'Zend/Pdf/Resource/Image.php';
+
+/**
+ * PNG image
+ *
+ * @package    Zend_Pdf
+ * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ */
+class Zend_Pdf_Resource_Image_Png extends Zend_Pdf_Resource_Image
+{
+    const PNG_COMPRESSION_DEFAULT_STRATEGY = 0;
+    const PNG_COMPRESSION_FILTERED = 1;
+    const PNG_COMPRESSION_HUFFMAN_ONLY = 2;
+    const PNG_COMPRESSION_RLE = 3;
+
+    const PNG_FILTER_NONE = 0;
+    const PNG_FILTER_SUB = 1;
+    const PNG_FILTER_UP = 2;
+    const PNG_FILTER_AVERAGE = 3;
+    const PNG_FILTER_PAETH = 4;
+
+    const PNG_INTERLACING_DISABLED = 0;
+    const PNG_INTERLACING_ENABLED = 1;
+
+    const PNG_CHANNEL_GRAY = 0;
+    const PNG_CHANNEL_RGB = 2;
+    const PNG_CHANNEL_INDEXED = 3;
+    const PNG_CHANNEL_GRAY_ALPHA = 4;
+    const PNG_CHANNEL_RGB_ALPHA = 6;
+
+    protected $_width;
+    protected $_height;
+    protected $_imageProperties;
+
+    /**
+     * 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 ) {
+            require_once 'Zend/Pdf/Exception.php';
+            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($imageFile, 3)) {
+            require_once 'Zend/Pdf/Exception.php';
+            throw new Zend_Pdf_Exception('Image is not a PNG');
+        }
+        fseek($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_Resource_Image_Png::PNG_INTERLACING_DISABLED) {
+            require_once 'Zend/Pdf/Exception.php';
+            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
+        $imageData = '';
+
+        /*
+         * The following loop processes PNG chunks. 4 Byte Longs are packed first give the chunk length
+         * followed by the chunk signature, a four byte code. IDAT and IEND are manditory in any PNG.
+         */
+        while (!feof($imageFile)) {
+            $chunkLengthBytes = fread($imageFile, 4);
+            if ($chunkLengthBytes === false) {
+                require_once 'Zend/Pdf/Exception.php';
+                throw new Zend_Pdf_Exception('Error ocuured while image file reading.');
+            }
+
+            $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_Resource_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_Resource_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($blue));
+                            break;
+
+                        case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_INDEXED:
+                            //Find the first transparent color in the index, we will mask that. (This is a bit of a hack. This should be a SMask and mask all entries values).
+                            if(($trnsIdx = strpos($trnsData, "\0")) !== false) {
+                                $transparencyData = array(new Zend_Pdf_Element_Numeric($trnsIdx),
+                                                          new Zend_Pdf_Element_Numeric($trnsIdx));
+                            }
+                            break;
+
+                        case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_GRAY_ALPHA:
+                            // Fall through to the next case
+
+                        case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_RGB_ALPHA:
+                            require_once 'Zend/Pdf/Exception.php';
+                            throw new Zend_Pdf_Exception( "tRNS chunk illegal for Alpha Channel Images" );
+                            break;
+                    }
+                    fseek($imageFile, 4, SEEK_CUR); //4 Byte Ending Sequence
+                    break;
+
+                case 'IEND';
+                    break 2; //End the loop too
+
+                default:
+                    fseek($imageFile, $chunkLength + 4, SEEK_CUR); //Skip the section
+                    break;
+            }
+        }
+        fclose($imageFile);
+
+        $compressed = true;
+        $imageDataTmp = '';
+        $smaskData = '';
+        switch ($color) {
+            case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_RGB:
+                $colorSpace = new Zend_Pdf_Element_Name('DeviceRGB');
+                break;
+
+            case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_GRAY:
+                $colorSpace = new Zend_Pdf_Element_Name('DeviceGray');
+                break;
+
+            case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_INDEXED:
+                if(empty($paletteData)) {
+                    require_once 'Zend/Pdf/Exception.php';
+                    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[] = $paletteObject;
+                break;
+
+            case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_GRAY_ALPHA:
+                /*
+                 * To decode PNG's with alpha data we must create two images from one. One image will contain the Gray data
+                 * the other will contain the Gray transparency overlay data. The former will become the object data and the latter
+                 * will become the Shadow Mask (SMask).
+                 */
+                if($bits > 8) {
+                    require_once 'Zend/Pdf/Exception.php';
+                    throw new Zend_Pdf_Exception("Alpha PNGs with bit depth > 8 are not yet supported");
+                }
+
+                $colorSpace = new Zend_Pdf_Element_Name('DeviceGray');
+
+                require_once 'Zend/Pdf/ElementFactory.php';
+                $decodingObjFactory = Zend_Pdf_ElementFactory::createFactory(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  = $imageDataTmp; //Overwrite image data with the gray channel without alpha
+                break;
+
+            case Zend_Pdf_Resource_Image_Png::PNG_CHANNEL_RGB_ALPHA:
+                /*
+                 * To decode PNG's with alpha data we must create two images from one. One image will contain the RGB data
+                 * the other will contain the Gray transparency overlay data. The former will become the object data and the latter
+                 * will become the Shadow Mask (SMask).
+                 */
+                if($bits > 8) {
+                    require_once 'Zend/Pdf/Exception.php';
+                    throw new Zend_Pdf_Exception("Alpha PNGs with bit depth > 8 are not yet supported");
+                }
+
+                $colorSpace = new Zend_Pdf_Element_Name('DeviceRGB');
+
+                require_once 'Zend/Pdf/ElementFactory.php';
+                $decodingObjFactory = Zend_Pdf_ElementFactory::createFactory(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  = $imageDataTmp; //Overwrite image data with the RGB channel without alpha
+                break;
+
+            default:
+                require_once 'Zend/Pdf/Exception.php';
+                throw new Zend_Pdf_Exception( "PNG Corruption: Invalid color space." );
+        }
+
+        if(empty($imageData)) {
+            require_once 'Zend/Pdf/Exception.php';
+            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_Resource_Image_Png::PNG_CHANNEL_RGB || $color==Zend_Pdf_Resource_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();
+        }
+    }
+
+    /**
+     * Image width
+     */
+    public function getPixelWidth() {
+    return $this->_width;
+    }
+
+    /**
+     * Image height
+     */
+    public function getPixelHeight() {
+        return $this->_height;
+    }
+
+    /**
+     * Image properties
+     */
+    public function getProperties() {
+        return $this->_imageProperties;
+    }
+}