module.graphic.png.php

一个用PHP编写的

<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <[e-mail]>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.graphic.png.php                                      //
// module for analyzing PNG Image files                        //
// dependencies: NONE                                          //
//                                                            ///
/////////////////////////////////////////////////////////////////


class getid3_png
{

	function getid3_png(&$fd, &$ThisFileInfo) {

	    // 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;