png.php

Bug tracker, and reporter.

                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)) {
                    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) {
                    throw new Zend_Pdf_Exception("Alpha PNGs with bit depth > 8 are not yet supported");
                }

                $colorSpace = new Zend_Pdf_Element_Name('DeviceGray');

                $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) {
                    throw new Zend_Pdf_Exception("Alpha PNGs with bit depth > 8 are not yet supported");
                }

                $colorSpace = new Zend_Pdf_Element_Name('DeviceRGB');

                $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:
                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_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;
    }
}