Public Member Functions

getid3_png Class Reference

getID3() by James Heinrich <info@getid3.org> // More...

Public Member Functions

 getid3_png (&$fd, &$ThisFileInfo)
 PNGsRGBintentLookup ($sRGB)
 PNGcompressionMethodLookup ($compressionmethod)
 PNGpHYsUnitLookup ($unitid)
 PNGoFFsUnitLookup ($unitid)
 PNGpCALequationTypeLookup ($equationtype)
 PNGsCALUnitLookup ($unitid)
 IHDRcalculateBitsPerSample ($color_type, $bit_depth)

Detailed Description

getID3() by James Heinrich <info@getid3.org> //

Definition at line 17 of file module.graphic.png.php.


Member Function Documentation

getid3_png::getid3_png ( &$  fd,
&$  ThisFileInfo 
)

Definition at line 20 of file module.graphic.png.php.

References getid3_lib::BigEndian2Int(), IHDRcalculateBitsPerSample(), PNGcompressionMethodLookup(), PNGoFFsUnitLookup(), PNGpCALequationTypeLookup(), PNGpHYsUnitLookup(), PNGsCALUnitLookup(), and PNGsRGBintentLookup().

                                                  {

            // shortcut
            $ThisFileInfo['png'] = array();
            $thisfile_png = &$ThisFileInfo['png'];

                $ThisFileInfo['fileformat']          = 'png';
                $ThisFileInfo['video']['dataformat'] = 'png';
                $ThisFileInfo['video']['lossless']   = false;

                fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
                $PNGfiledata = fread($fd, GETID3_FREAD_BUFFER_SIZE);
                $offset = 0;

                $PNGidentifier = substr($PNGfiledata, $offset, 8); // $89 $50 $4E $47 $0D $0A $1A $0A
                $offset += 8;

                if ($PNGidentifier != "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A") {
                        $ThisFileInfo['error'][] = 'First 8 bytes of file ('.getid3_lib::PrintHexBytes($PNGidentifier).') did not match expected PNG identifier';
                        unset($ThisFileInfo['fileformat']);
                        return false;
                }

                while (((ftell($fd) - (strlen($PNGfiledata) - $offset)) < $ThisFileInfo['filesize'])) {
                        $chunk['data_length'] = getid3_lib::BigEndian2Int(substr($PNGfiledata, $offset, 4));
                        $offset += 4;
                        while (((strlen($PNGfiledata) - $offset) < ($chunk['data_length'] + 4)) && (ftell($fd) < $ThisFileInfo['filesize'])) {
                                $PNGfiledata .= fread($fd, GETID3_FREAD_BUFFER_SIZE);
                        }
                        $chunk['type_text']   =               substr($PNGfiledata, $offset, 4);
                        $offset += 4;
                        $chunk['type_raw']    = getid3_lib::BigEndian2Int($chunk['type_text']);
                        $chunk['data']        =               substr($PNGfiledata, $offset, $chunk['data_length']);
                        $offset += $chunk['data_length'];
                        $chunk['crc']         = getid3_lib::BigEndian2Int(substr($PNGfiledata, $offset, 4));
                        $offset += 4;

                        $chunk['flags']['ancilliary']   = (bool) ($chunk['type_raw'] & 0x20000000);
                        $chunk['flags']['private']      = (bool) ($chunk['type_raw'] & 0x00200000);
                        $chunk['flags']['reserved']     = (bool) ($chunk['type_raw'] & 0x00002000);
                        $chunk['flags']['safe_to_copy'] = (bool) ($chunk['type_raw'] & 0x00000020);

                        // shortcut
                        $thisfile_png[$chunk['type_text']] = array();
                        $thisfile_png_chunk_type_text = &$thisfile_png[$chunk['type_text']];

                        switch ($chunk['type_text']) {

                                case 'IHDR': // Image Header
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        $thisfile_png_chunk_type_text['width']                     = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  0, 4));
                                        $thisfile_png_chunk_type_text['height']                    = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  4, 4));
                                        $thisfile_png_chunk_type_text['raw']['bit_depth']          = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  8, 1));
                                        $thisfile_png_chunk_type_text['raw']['color_type']         = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  9, 1));
                                        $thisfile_png_chunk_type_text['raw']['compression_method'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 10, 1));
                                        $thisfile_png_chunk_type_text['raw']['filter_method']      = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 11, 1));
                                        $thisfile_png_chunk_type_text['raw']['interlace_method']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 12, 1));

                                        $thisfile_png_chunk_type_text['compression_method_text']   = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['raw']['compression_method']);
                                        $thisfile_png_chunk_type_text['color_type']['palette']     = (bool) ($thisfile_png_chunk_type_text['raw']['color_type'] & 0x01);
                                        $thisfile_png_chunk_type_text['color_type']['true_color']  = (bool) ($thisfile_png_chunk_type_text['raw']['color_type'] & 0x02);
                                        $thisfile_png_chunk_type_text['color_type']['alpha']       = (bool) ($thisfile_png_chunk_type_text['raw']['color_type'] & 0x04);

                                        $ThisFileInfo['video']['resolution_x']    = $thisfile_png_chunk_type_text['width'];
                                        $ThisFileInfo['video']['resolution_y']    = $thisfile_png_chunk_type_text['height'];

                                        $ThisFileInfo['video']['bits_per_sample'] = $this->IHDRcalculateBitsPerSample($thisfile_png_chunk_type_text['raw']['color_type'], $thisfile_png_chunk_type_text['raw']['bit_depth']);
                                        break;


                                case 'PLTE': // Palette
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        $paletteoffset = 0;
                                        for ($i = 0; $i <= 255; $i++) {
                                                //$thisfile_png_chunk_type_text['red'][$i]   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
                                                //$thisfile_png_chunk_type_text['green'][$i] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
                                                //$thisfile_png_chunk_type_text['blue'][$i]  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
                                                $red   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
                                                $green = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
                                                $blue  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
                                                $thisfile_png_chunk_type_text[$i] = (($red << 16) | ($green << 8) | ($blue));
                                        }
                                        break;


                                case 'tRNS': // Transparency
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        switch ($thisfile_png['IHDR']['raw']['color_type']) {
                                                case 0:
                                                        $thisfile_png_chunk_type_text['transparent_color_gray']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 2));
                                                        break;

                                                case 2:
                                                        $thisfile_png_chunk_type_text['transparent_color_red']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 2));
                                                        $thisfile_png_chunk_type_text['transparent_color_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 2));
                                                        $thisfile_png_chunk_type_text['transparent_color_blue']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 2));
                                                        break;

                                                case 3:
                                                        for ($i = 0; $i < strlen($thisfile_png_chunk_type_text['header']['data']); $i++) {
                                                                $thisfile_png_chunk_type_text['palette_opacity'][$i] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $i, 1));
                                                        }
                                                        break;

                                                case 4:
                                                case 6:
                                                        $ThisFileInfo['error'][] = 'Invalid color_type in tRNS chunk: '.$thisfile_png['IHDR']['raw']['color_type'];

                                                default:
                                                        $ThisFileInfo['warning'][] = 'Unhandled color_type in tRNS chunk: '.$thisfile_png['IHDR']['raw']['color_type'];
                                                        break;
                                        }
                                        break;


                                case 'gAMA': // Image Gamma
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        $thisfile_png_chunk_type_text['gamma']  = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']) / 100000;
                                        break;


                                case 'cHRM': // Primary Chromaticities
                                        $thisfile_png_chunk_type_text['header']  = $chunk;
                                        $thisfile_png_chunk_type_text['white_x'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  0, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['white_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  4, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['red_y']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'],  8, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['red_y']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 12, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['green_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 16, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['green_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 20, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['blue_y']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 24, 4)) / 100000;
                                        $thisfile_png_chunk_type_text['blue_y']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 28, 4)) / 100000;
                                        break;


                                case 'sRGB': // Standard RGB Color Space
                                        $thisfile_png_chunk_type_text['header']                 = $chunk;
                                        $thisfile_png_chunk_type_text['reindering_intent']      = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']);
                                        $thisfile_png_chunk_type_text['reindering_intent_text'] = $this->PNGsRGBintentLookup($thisfile_png_chunk_type_text['reindering_intent']);
                                        break;


                                case 'iCCP': // Embedded ICC Profile
                                        $thisfile_png_chunk_type_text['header']                  = $chunk;
                                        list($profilename, $compressiondata)                                 = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
                                        $thisfile_png_chunk_type_text['profile_name']            = $profilename;
                                        $thisfile_png_chunk_type_text['compression_method']      = getid3_lib::BigEndian2Int(substr($compressiondata, 0, 1));
                                        $thisfile_png_chunk_type_text['compression_profile']     = substr($compressiondata, 1);

                                        $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['compression_method']);
                                        break;


                                case 'tEXt': // Textual Data
                                        $thisfile_png_chunk_type_text['header']  = $chunk;
                                        list($keyword, $text)                                = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
                                        $thisfile_png_chunk_type_text['keyword'] = $keyword;
                                        $thisfile_png_chunk_type_text['text']    = $text;

                                        $thisfile_png['comments'][$thisfile_png_chunk_type_text['keyword']][] = $thisfile_png_chunk_type_text['text'];
                                        break;


                                case 'zTXt': // Compressed Textual Data
                                        $thisfile_png_chunk_type_text['header']                  = $chunk;
                                        list($keyword, $otherdata)                                           = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
                                        $thisfile_png_chunk_type_text['keyword']                 = $keyword;
                                        $thisfile_png_chunk_type_text['compression_method']      = getid3_lib::BigEndian2Int(substr($otherdata, 0, 1));
                                        $thisfile_png_chunk_type_text['compressed_text']         = substr($otherdata, 1);
                                        $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['compression_method']);
                                        switch ($thisfile_png_chunk_type_text['compression_method']) {
                                                case 0:
                                                        $thisfile_png_chunk_type_text['text']            = gzuncompress($thisfile_png_chunk_type_text['compressed_text']);
                                                        break;

                                                default:
                                                        // unknown compression method
                                                        break;
                                        }

                                        if (isset($thisfile_png_chunk_type_text['text'])) {
                                                $thisfile_png['comments'][$thisfile_png_chunk_type_text['keyword']][] = $thisfile_png_chunk_type_text['text'];
                                        }
                                        break;


                                case 'iTXt': // International Textual Data
                                        $thisfile_png_chunk_type_text['header']                  = $chunk;
                                        list($keyword, $otherdata)                                           = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
                                        $thisfile_png_chunk_type_text['keyword']                 = $keyword;
                                        $thisfile_png_chunk_type_text['compression']             = (bool) getid3_lib::BigEndian2Int(substr($otherdata, 0, 1));
                                        $thisfile_png_chunk_type_text['compression_method']      = getid3_lib::BigEndian2Int(substr($otherdata, 1, 1));
                                        $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['compression_method']);
                                        list($languagetag, $translatedkeyword, $text)                        = explode("\x00", substr($otherdata, 2), 3);
                                        $thisfile_png_chunk_type_text['language_tag']            = $languagetag;
                                        $thisfile_png_chunk_type_text['translated_keyword']      = $translatedkeyword;

                                        if ($thisfile_png_chunk_type_text['compression']) {

                                                switch ($thisfile_png_chunk_type_text['compression_method']) {
                                                        case 0:
                                                                $thisfile_png_chunk_type_text['text']        = gzuncompress($text);
                                                                break;

                                                        default:
                                                                // unknown compression method
                                                                break;
                                                }

                                        } else {

                                                $thisfile_png_chunk_type_text['text']                = $text;

                                        }

                                        if (isset($thisfile_png_chunk_type_text['text'])) {
                                                $thisfile_png['comments'][$thisfile_png_chunk_type_text['keyword']][] = $thisfile_png_chunk_type_text['text'];
                                        }
                                        break;


                                case 'bKGD': // Background Color
                                        $thisfile_png_chunk_type_text['header']                   = $chunk;
                                        switch ($thisfile_png['IHDR']['raw']['color_type']) {
                                                case 0:
                                                case 4:
                                                        $thisfile_png_chunk_type_text['background_gray']  = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']);
                                                        break;

                                                case 2:
                                                case 6:
                                                        $thisfile_png_chunk_type_text['background_red']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0 * $thisfile_png['IHDR']['raw']['bit_depth'], $thisfile_png['IHDR']['raw']['bit_depth']));
                                                        $thisfile_png_chunk_type_text['background_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1 * $thisfile_png['IHDR']['raw']['bit_depth'], $thisfile_png['IHDR']['raw']['bit_depth']));
                                                        $thisfile_png_chunk_type_text['background_blue']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2 * $thisfile_png['IHDR']['raw']['bit_depth'], $thisfile_png['IHDR']['raw']['bit_depth']));
                                                        break;

                                                case 3:
                                                        $thisfile_png_chunk_type_text['background_index'] = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']);
                                                        break;

                                                default:
                                                        break;
                                        }
                                        break;


                                case 'pHYs': // Physical Pixel Dimensions
                                        $thisfile_png_chunk_type_text['header']                 = $chunk;
                                        $thisfile_png_chunk_type_text['pixels_per_unit_x']      = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 4));
                                        $thisfile_png_chunk_type_text['pixels_per_unit_y']      = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 4));
                                        $thisfile_png_chunk_type_text['unit_specifier']         = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 8, 1));
                                        $thisfile_png_chunk_type_text['unit']                   = $this->PNGpHYsUnitLookup($thisfile_png_chunk_type_text['unit_specifier']);
                                        break;


                                case 'sBIT': // Significant Bits
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        switch ($thisfile_png['IHDR']['raw']['color_type']) {
                                                case 0:
                                                        $thisfile_png_chunk_type_text['significant_bits_gray']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
                                                        break;

                                                case 2:
                                                case 3:
                                                        $thisfile_png_chunk_type_text['significant_bits_red']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
                                                        $thisfile_png_chunk_type_text['significant_bits_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
                                                        $thisfile_png_chunk_type_text['significant_bits_blue']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 1));
                                                        break;

                                                case 4:
                                                        $thisfile_png_chunk_type_text['significant_bits_gray']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
                                                        $thisfile_png_chunk_type_text['significant_bits_alpha'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
                                                        break;

                                                case 6:
                                                        $thisfile_png_chunk_type_text['significant_bits_red']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
                                                        $thisfile_png_chunk_type_text['significant_bits_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
                                                        $thisfile_png_chunk_type_text['significant_bits_blue']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 1));
                                                        $thisfile_png_chunk_type_text['significant_bits_alpha'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 3, 1));
                                                        break;

                                                default:
                                                        break;
                                        }
                                        break;


                                case 'sPLT': // Suggested Palette
                                        $thisfile_png_chunk_type_text['header']                           = $chunk;
                                        list($palettename, $otherdata)                                                = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
                                        $thisfile_png_chunk_type_text['palette_name']                     = $palettename;
                                        $sPLToffset = 0;
                                        $thisfile_png_chunk_type_text['sample_depth_bits']                = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, 1));
                                        $sPLToffset += 1;
                                        $thisfile_png_chunk_type_text['sample_depth_bytes']               = $thisfile_png_chunk_type_text['sample_depth_bits'] / 8;
                                        $paletteCounter = 0;
                                        while ($sPLToffset < strlen($otherdata)) {
                                                $thisfile_png_chunk_type_text['red'][$paletteCounter]       = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
                                                $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
                                                $thisfile_png_chunk_type_text['green'][$paletteCounter]     = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
                                                $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
                                                $thisfile_png_chunk_type_text['blue'][$paletteCounter]      = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
                                                $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
                                                $thisfile_png_chunk_type_text['alpha'][$paletteCounter]     = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
                                                $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
                                                $thisfile_png_chunk_type_text['frequency'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, 2));
                                                $sPLToffset += 2;
                                                $paletteCounter++;
                                        }
                                        break;


                                case 'hIST': // Palette Histogram
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        $hISTcounter = 0;
                                        while ($hISTcounter < strlen($thisfile_png_chunk_type_text['header']['data'])) {
                                                $thisfile_png_chunk_type_text[$hISTcounter] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $hISTcounter / 2, 2));
                                                $hISTcounter += 2;
                                        }
                                        break;


                                case 'tIME': // Image Last-Modification Time
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        $thisfile_png_chunk_type_text['year']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 2));
                                        $thisfile_png_chunk_type_text['month']  = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 1));
                                        $thisfile_png_chunk_type_text['day']    = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 3, 1));
                                        $thisfile_png_chunk_type_text['hour']   = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 1));
                                        $thisfile_png_chunk_type_text['minute'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 5, 1));
                                        $thisfile_png_chunk_type_text['second'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 6, 1));
                                        $thisfile_png_chunk_type_text['unix']   = gmmktime($thisfile_png_chunk_type_text['hour'], $thisfile_png_chunk_type_text['minute'], $thisfile_png_chunk_type_text['second'], $thisfile_png_chunk_type_text['month'], $thisfile_png_chunk_type_text['day'], $thisfile_png_chunk_type_text['year']);
                                        break;


                                case 'oFFs': // Image Offset
                                        $thisfile_png_chunk_type_text['header']         = $chunk;
                                        $thisfile_png_chunk_type_text['position_x']     = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 4), false, true);
                                        $thisfile_png_chunk_type_text['position_y']     = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 4), false, true);
                                        $thisfile_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 8, 1));
                                        $thisfile_png_chunk_type_text['unit']           = $this->PNGoFFsUnitLookup($thisfile_png_chunk_type_text['unit_specifier']);
                                        break;


                                case 'pCAL': // Calibration Of Pixel Values
                                        $thisfile_png_chunk_type_text['header']             = $chunk;
                                        list($calibrationname, $otherdata)                              = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
                                        $thisfile_png_chunk_type_text['calibration_name']   = $calibrationname;
                                        $pCALoffset = 0;
                                        $thisfile_png_chunk_type_text['original_zero']      = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 4), false, true);
                                        $pCALoffset += 4;
                                        $thisfile_png_chunk_type_text['original_max']       = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 4), false, true);
                                        $pCALoffset += 4;
                                        $thisfile_png_chunk_type_text['equation_type']      = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 1));
                                        $pCALoffset += 1;
                                        $thisfile_png_chunk_type_text['equation_type_text'] = $this->PNGpCALequationTypeLookup($thisfile_png_chunk_type_text['equation_type']);
                                        $thisfile_png_chunk_type_text['parameter_count']    = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 1));
                                        $pCALoffset += 1;
                                        $thisfile_png_chunk_type_text['parameters']         = explode("\x00", substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset));
                                        break;


                                case 'sCAL': // Physical Scale Of Image Subject
                                        $thisfile_png_chunk_type_text['header']         = $chunk;
                                        $thisfile_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
                                        $thisfile_png_chunk_type_text['unit']           = $this->PNGsCALUnitLookup($thisfile_png_chunk_type_text['unit_specifier']);
                                        list($pixelwidth, $pixelheight)                             = explode("\x00", substr($thisfile_png_chunk_type_text['header']['data'], 1));
                                        $thisfile_png_chunk_type_text['pixel_width']    = $pixelwidth;
                                        $thisfile_png_chunk_type_text['pixel_height']   = $pixelheight;
                                        break;


                                case 'gIFg': // GIF Graphic Control Extension
                                        $gIFgCounter = 0;
                                        if (isset($thisfile_png_chunk_type_text) && is_array($thisfile_png_chunk_type_text)) {
                                                $gIFgCounter = count($thisfile_png_chunk_type_text);
                                        }
                                        $thisfile_png_chunk_type_text[$gIFgCounter]['header']          = $chunk;
                                        $thisfile_png_chunk_type_text[$gIFgCounter]['disposal_method'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
                                        $thisfile_png_chunk_type_text[$gIFgCounter]['user_input_flag'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
                                        $thisfile_png_chunk_type_text[$gIFgCounter]['delay_time']      = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 2));
                                        break;


                                case 'gIFx': // GIF Application Extension
                                        $gIFxCounter = 0;
                                        if (isset($thisfile_png_chunk_type_text) && is_array($thisfile_png_chunk_type_text)) {
                                                $gIFxCounter = count($thisfile_png_chunk_type_text);
                                        }
                                        $thisfile_png_chunk_type_text[$gIFxCounter]['header']                 = $chunk;
                                        $thisfile_png_chunk_type_text[$gIFxCounter]['application_identifier'] = substr($thisfile_png_chunk_type_text['header']['data'],  0, 8);
                                        $thisfile_png_chunk_type_text[$gIFxCounter]['authentication_code']    = substr($thisfile_png_chunk_type_text['header']['data'],  8, 3);
                                        $thisfile_png_chunk_type_text[$gIFxCounter]['application_data']       = substr($thisfile_png_chunk_type_text['header']['data'], 11);
                                        break;


                                case 'IDAT': // Image Data
                                        $idatinformationfieldindex = 0;
                                        if (isset($thisfile_png['IDAT']) && is_array($thisfile_png['IDAT'])) {
                                                $idatinformationfieldindex = count($thisfile_png['IDAT']);
                                        }
                                        unset($chunk['data']);
                                        $thisfile_png_chunk_type_text[$idatinformationfieldindex]['header'] = $chunk;
                                        break;


                                case 'IEND': // Image Trailer
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        break;


                                default:
                                        //unset($chunk['data']);
                                        $thisfile_png_chunk_type_text['header'] = $chunk;
                                        $ThisFileInfo['warning'][] = 'Unhandled chunk type: '.$chunk['type_text'];
                                        break;
                        }
                }

                return true;
        }

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getid3_png::IHDRcalculateBitsPerSample ( color_type,
bit_depth 
)

Definition at line 491 of file module.graphic.png.php.

Referenced by getid3_png().

                                                                     {
                switch ($color_type) {
                        case 0: // Each pixel is a grayscale sample.
                                return $bit_depth;
                                break;

                        case 2: // Each pixel is an R,G,B triple
                                return 3 * $bit_depth;
                                break;

                        case 3: // Each pixel is a palette index; a PLTE chunk must appear.
                                return $bit_depth;
                                break;

                        case 4: // Each pixel is a grayscale sample, followed by an alpha sample.
                                return 2 * $bit_depth;
                                break;

                        case 6: // Each pixel is an R,G,B triple, followed by an alpha sample.
                                return 4 * $bit_depth;
                                break;
                }
                return false;
        }

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getid3_png::PNGcompressionMethodLookup ( compressionmethod  ) 

Definition at line 450 of file module.graphic.png.php.

Referenced by getid3_png().

                                                                {
                static $PNGcompressionMethodLookup = array(
                        0 => 'deflate/inflate'
                );
                return (isset($PNGcompressionMethodLookup[$compressionmethod]) ? $PNGcompressionMethodLookup[$compressionmethod] : 'invalid');
        }

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getid3_png::PNGoFFsUnitLookup ( unitid  ) 

Definition at line 465 of file module.graphic.png.php.

Referenced by getid3_png().

                                            {
                static $PNGoFFsUnitLookup = array(
                        0 => 'pixel',
                        1 => 'micrometer'
                );
                return (isset($PNGoFFsUnitLookup[$unitid]) ? $PNGoFFsUnitLookup[$unitid] : 'invalid');
        }

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getid3_png::PNGpCALequationTypeLookup ( equationtype  ) 

Definition at line 473 of file module.graphic.png.php.

Referenced by getid3_png().

                                                          {
                static $PNGpCALequationTypeLookup = array(
                        0 => 'Linear mapping',
                        1 => 'Base-e exponential mapping',
                        2 => 'Arbitrary-base exponential mapping',
                        3 => 'Hyperbolic mapping'
                );
                return (isset($PNGpCALequationTypeLookup[$equationtype]) ? $PNGpCALequationTypeLookup[$equationtype] : 'invalid');
        }

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getid3_png::PNGpHYsUnitLookup ( unitid  ) 

Definition at line 457 of file module.graphic.png.php.

Referenced by getid3_png().

                                            {
                static $PNGpHYsUnitLookup = array(
                        0 => 'unknown',
                        1 => 'meter'
                );
                return (isset($PNGpHYsUnitLookup[$unitid]) ? $PNGpHYsUnitLookup[$unitid] : 'invalid');
        }

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getid3_png::PNGsCALUnitLookup ( unitid  ) 

Definition at line 483 of file module.graphic.png.php.

Referenced by getid3_png().

                                            {
                static $PNGsCALUnitLookup = array(
                        0 => 'meter',
                        1 => 'radian'
                );
                return (isset($PNGsCALUnitLookup[$unitid]) ? $PNGsCALUnitLookup[$unitid] : 'invalid');
        }

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getid3_png::PNGsRGBintentLookup ( sRGB  ) 

Definition at line 440 of file module.graphic.png.php.

Referenced by getid3_png().

                                            {
                static $PNGsRGBintentLookup = array(
                        0 => 'Perceptual',
                        1 => 'Relative colorimetric',
                        2 => 'Saturation',
                        3 => 'Absolute colorimetric'
                );
                return (isset($PNGsRGBintentLookup[$sRGB]) ? $PNGsRGBintentLookup[$sRGB] : 'invalid');
        }

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The documentation for this class was generated from the following file: