ethics-canvas/canvas/mpdf/utils/image_details.php

<?php

$orig_srcpath='../tests/tiger.png';						// as specified in your file (could be full URL)
$file = 'http://127.0.0.1/MPDF1.com/common/mpdf/tests/tiger.png';	// Full URL
$fileIsLocal = true;									// is the file in the same domain?

//======================================================================

$ppUx = 0;
$type = '';
$data = '';

echo 'File: ' .$orig_srcpath . '<br />';
echo 'Full File URL: ' .$file . '<br />';
 		if ($orig_srcpath && $fileIsLocal && $check = @fopen($orig_srcpath,"rb")) {
			fclose($check);
			$file=$orig_srcpath;
			$data = file_get_contents($file);
			$type = _imageTypeFromString($data);
			echo 'File accessed using fopen on $orig_srcpath' . '<br />';
		}
		if (!$data && $check = @fopen($file,"rb")) {
			fclose($check);
			$data = file_get_contents($file);
			$type = _imageTypeFromString($data);
			echo 'File accessed using fopen on $file' . '<br />';
		}
		if ((!$data || !$type) && !ini_get('allow_url_fopen') ) {	// only worth trying if remote file and !ini_get('allow_url_fopen')
			file_get_contents_by_socket($file, $data);	// needs full url?? even on local (never needed for local)
			if ($data) { $type = _imageTypeFromString($data); }
			echo 'File accessed using socket ' . '<br />';
		}
		if ((!$data || !$type) && !ini_get('allow_url_fopen') && function_exists("curl_init")) {
			file_get_contents_by_curl($file, $data);		// needs full url?? even on local (never needed for local)
			if ($data) { $type = _imageTypeFromString($data); }
			echo 'File accessed using cURL ' . '<br />';
		}



	if (!$data) { echo 'Could not access image file' . '<br />'; exit; }

	echo 'Image type determined: ' .strtoupper($type) . '<br />';

	// JPEG
	if ($type == 'jpeg' || $type == 'jpg') {
		$hdr = _jpgHeaderFromString($data);
		if (!$hdr) { echo 'Error parsing JPG header' . '<br />'; exit; }
		$a = _jpgDataFromHeader($hdr);
		$channels = intval($a[4]);
		echo 'Width: ' . $a[0]. '<br />';
		echo 'Height: ' . $a[1]. '<br />';
		echo 'Colorspace: ' . $a[2]. '<br />';
		echo 'BPC (bits per channel): ' . $a[3]. '<br />';
		echo 'Channels: ' . $channels. '<br />';

		$j = strpos($data,'JFIF');
		if ($j) {
			//Read resolution
			$unitSp=ord(substr($data,($j+7),1));
			if ($unitSp > 0) {
				$ppUx=_twobytes2int(substr($data,($j+8),2));	// horizontal pixels per meter, usually set to zero
				if ($unitSp == 2) {	// = dots per cm (if == 1 set as dpi)
					$ppUx=round($ppUx/10 *25.4);
				}
			}
			echo 'Resolution ppUx: ' . $ppUx. '<br />';
		}
		else echo 'JFIF not found in header' . '<br />';


			// mPDF 6 ICC profile
			$offset = 0;
			$icc = array();
			while (($pos = strpos($data, "ICC_PROFILE\0", $offset)) !== false) {
				// get ICC sequence length
				$length = _twobytes2int(substr($data, ($pos - 2),2)) - 16;
				$sn = max(1, ord($data[($pos + 12)]));
				$nom = max(1, ord($data[($pos + 13)]));
				$icc[($sn - 1)] = substr($data, ($pos + 14), $length);
				$offset = ($pos + 14 + $length);
			}
			// order and compact ICC segments
			if (count($icc) > 0) {
				echo 'ICC profile present' . '<br />';
				ksort($icc);
				$icc = implode('', $icc);
				if (substr($icc, 36, 4) != 'acsp') {
					// invalid ICC profile
					echo 'ICC profile INVALID (no acsp flag)' . '<br />';
				}
				$input = substr($icc, 16, 4);
				$output = substr($icc, 20, 4);
				echo 'ICC profile Input: ' . $input. '<br />';
				echo 'ICC profile Output: ' . $output. '<br />';
				// Ignore Color profiles for conversion to other colorspaces e.g. CMYK/Lab
				if ($input != 'RGB ' || $output != 'XYZ ') { echo 'ICC profile ignored by mPDF' . '<br />'; }
			}

	}

	// PNG
	else if ($type == 'png') {
		//Check signature
		if(substr($data,0,8)!=chr(137).'PNG'.chr(13).chr(10).chr(26).chr(10)) {
			echo 'Error parsing PNG identifier<br />';  exit;
		}
		//Read header chunk
		if(substr($data,12,4)!='IHDR') {
			echo 'Incorrect PNG file (no IHDR block found)<br />'; exit;
		}

		$w=_fourbytes2int(substr($data,16,4));
		$h=_fourbytes2int(substr($data,20,4));
		$bpc=ord(substr($data,24,1));
		$errpng = false;
		$pngalpha = false;
		$channels = 0;

		echo 'Width: ' .$w . '<br />';
		echo 'Height: ' .$h . '<br />';
		echo 'BPC (bits per channel): ' .$bpc . '<br />';

		$ct=ord(substr($data,25,1));
		if($ct==0) { $colspace='DeviceGray'; $channels = 1; }
		elseif($ct==2) { $colspace='DeviceRGB'; $channels = 3; }
		elseif($ct==3) { $colspace='Indexed'; $channels = 1; }
		elseif($ct==4) { $colspace='DeviceGray';  $channels = 1; $errpng = 'alpha channel'; $pngalpha = true; }
		else { $colspace='DeviceRGB'; $channels = 3; $errpng = 'alpha channel'; $pngalpha = true; }

		echo 'Colorspace: ' . $colspace. '<br />';
		echo 'Channels: ' . $channels. '<br />';
		if ($pngalpha) echo 'Alpha channel detected'. '<br />';

		if ($ct < 4 && strpos($data,'tRNS')!==false) {	echo 'Transparency detected'. '<br />'; $errpng = 'transparency'; $pngalpha = true;}

		if ($ct == 3 && strpos($data,'iCCP')!==false) {	echo 'Indexed plus ICC'. '<br />'; $errpng = 'indexed plus ICC'; }

		if(ord(substr($data,26,1))!=0) { echo 'compression method not set to zero<br />'; $errpng = 'compression method'; }	// only 0 should be specified
		if(ord(substr($data,27,1))!=0) { echo 'filter method not set to zero<br />'; $errpng = 'filter method'; }		// only 0 should be specified
		if(ord(substr($data,28,1))!=0) { echo 'interlaced file not set to zero<br />'; $errpng = 'interlaced file'; }

		$j = strpos($data,'pHYs');
		if ($j) {
			//Read resolution
			$unitSp=ord(substr($data,($j+12),1));
			if ($unitSp == 1) {
				$ppUx=_fourbytes2int(substr($data,($j+4),4));	// horizontal pixels per meter, usually set to zero
				$ppUx=round($ppUx/1000 *25.4);
			}
			echo 'Resolution ppUx: ' . $ppUx. '<br />';
		}

		// mPDF 6 Gamma correction
		$gamma_correction = 0;
		$gAMA = 0;
		$j = strpos($data,'gAMA');
		if ($j && strpos($data,'sRGB')===false) {	// sRGB colorspace - overrides gAMA
			$gAMA=_fourbytes2int(substr($data,($j+4),4));	// Gamma value times 100000
			$gAMA /= 100000;

		}

		if ($gAMA) { $gamma_correction = 1/$gAMA; }

		// Don't need to apply gamma correction if == default i.e. 2.2
		if ($gamma_correction > 2.15 && $gamma_correction < 2.25) { $gamma_correction = 0; }

		if ($gamma_correction) { echo 'Gamma correction detected'. '<br />';  }

		// NOT supported at present
		if (strpos($data,'sRGB')!==false)	echo 'sRGB colorspace - NOT supported at present'. '<br />';
		if (strpos($data,'cHRM')!==false)	echo 'Chromaticity and Whitepoint - NOT supported at present'. '<br />';

		if (($errpng || $pngalpha || $gamma_correction)) {
			if (function_exists('gd_info')) { $gd = gd_info(); }
			else {$gd = array(); }
			if (!isset($gd['PNG Support'])) { echo 'GD library required for PNG image ('.$errpng.')'. '<br />';}
			$im = imagecreatefromstring($data);

			if (!$im) { echo 'Error creating GD image from PNG file ('.$errpng.')'. '<br />';}
			$w = imagesx($im);
			$h = imagesy($im);
			if ($im) {

			   // Alpha channel set (including using tRNS for Paletted images)
			   if ($pngalpha) {
				echo 'Alpha channel will be used by mPDF (including when tRNS present in Paletted images)<br />';
				if ($colspace=='Indexed') { echo '...Generating Alpha channel values from tRNS (Indexed)<br />'; }
				else if ($ct===0 || $ct==2) { echo '...Generating Alpha channel values from tRNS (non-Indexed)<br />'; }
				else { echo '...Extracting Alpha channel<br />'; }


			   }
			   else { 	// No alpha/transparency set (but cannot read directly because e.g. bit-depth != 8, interlaced etc)
				echo 'No alpha/transparency set (but cannot read directly because e.g. bit-depth != 8, interlaced etc)<br />';

				// ICC profile
				$icc = false;
				$p = strpos($data,'iCCP');
				if ($p && $colspace=="Indexed") {
					$p += 4;
					$n=_fourbytes2int(substr($data,($p-8),4));
					$nullsep = strpos(substr($data,$p,80), chr(0));
					$icc = substr($data, ($p+$nullsep+2), ($n-($nullsep+2)) );
					// Test if file is gzcompressed
					if (ord(substr($str, 0, 1)) == 0x1f && ord(substr($str, 1, 1)) == 0x8b) {
						$icc = @gzuncompress($icc);	// Ignored if fails
					}
					if ($icc) {
						echo 'ICC profile present' . '<br />';
						if (substr($icc, 36, 4) != 'acsp') { echo 'ICC profile INVALID (no acsp flag)' . '<br />'; $icc = false; }	// invalid ICC profile
						else {
							$input = substr($icc, 16, 4);
							$output = substr($icc, 20, 4);
							echo 'ICC profile Input: ' . $input. '<br />';
							echo 'ICC profile Output: ' . $output. '<br />';
							// Ignore Color profiles for conversion to other colorspaces e.g. CMYK/Lab
							if ($input != 'RGB ' || $output != 'XYZ ') { $icc = false; echo 'ICC profile ignored by mPDF' . '<br />'; }
						}
					}
					// Convert to RGB colorspace so can use ICC Profile
					if ($icc) { echo 'ICC profile and Indexed colorspace both present - need to Convert to RGB colorspace so can use ICC Profile<br />'; }
				}


			   }
			}
			echo 'PNG Image parsed on second pass' . '<br />';

			// SECOND PASS
			imagealphablending($im, false);
			imagesavealpha($im, false);
			imageinterlace($im, false);
			ob_start();
			$check = @imagepng($im);
			if (!$check) { echo 'Error creating temporary image object whilst using GD library to parse PNG image' . '<br />'; }
			$data = ob_get_contents();
			ob_end_clean();
			if (!$data) { echo 'Error parsing temporary file image object created with GD library to parse PNG image' . '<br />'; }
			imagedestroy($im);


			//Check signature
			if(substr($data,0,8)!=chr(137).'PNG'.chr(13).chr(10).chr(26).chr(10)) {
				echo 'Error parsing PNG identifier<br />';  exit;
			}
			//Read header chunk
			if(substr($data,12,4)!='IHDR') {
				echo 'Incorrect PNG file (no IHDR block found)<br />'; exit;
			}

			$w=_fourbytes2int(substr($data,16,4));
			$h=_fourbytes2int(substr($data,20,4));
			$bpc=ord(substr($data,24,1));
			$errpng = false;
			$pngalpha = false;
			$channels = 0;

			echo 'Width: ' .$w . '<br />';
			echo 'Height: ' .$h . '<br />';
			echo 'BPC (bits per channel): ' .$bpc . '<br />';

			$ct=ord(substr($data,25,1));
			if($ct==0) { $colspace='DeviceGray'; $channels = 1; }
			elseif($ct==2) { $colspace='DeviceRGB'; $channels = 3; }
			elseif($ct==3) { $colspace='Indexed'; $channels = 1; }
			elseif($ct==4) { $colspace='DeviceGray';  $channels = 1; $errpng = 'alpha channel'; $pngalpha = true; }
			else { $colspace='DeviceRGB'; $channels = 3; $errpng = 'alpha channel'; $pngalpha = true; }

			echo 'Colorspace: ' . $colspace. '<br />';
			echo 'Channels: ' . $channels. '<br />';
			if ($pngalpha) echo 'Alpha channel detected'. '<br />';

			if ($ct < 4 && strpos($data,'tRNS')!==false) {	echo 'Transparency detected'. '<br />'; $errpng = 'transparency'; $pngalpha = true;}

			if ($ct == 3 && strpos($data,'iCCP')!==false) {	echo 'Indexed plus ICC'. '<br />'; $errpng = 'indexed plus ICC'; }

			if(ord(substr($data,26,1))!=0) { echo 'compression method not set to zero<br />'; $errpng = 'compression method'; }	// only 0 should be specified
			if(ord(substr($data,27,1))!=0) { echo 'filter method not set to zero<br />'; $errpng = 'filter method'; }		// only 0 should be specified
			if(ord(substr($data,28,1))!=0) { echo 'interlaced file not set to zero<br />'; $errpng = 'interlaced file'; }

			$j = strpos($data,'pHYs');
			if ($j) {
				//Read resolution
				$unitSp=ord(substr($data,($j+12),1));
				if ($unitSp == 1) {
					$ppUx=_fourbytes2int(substr($data,($j+4),4));	// horizontal pixels per meter, usually set to zero
					$ppUx=round($ppUx/1000 *25.4);
				}
				echo 'Resolution ppUx: ' . $ppUx. '<br />';
			}

			//Gamma correction
			$gamma_correction = 0;
			$gAMA = 0;
			$j = strpos($data,'gAMA');
			if ($j && strpos($data,'sRGB')===false) {	// sRGB colorspace - overrides gAMA
				$gAMA=_fourbytes2int(substr($data,($j+4),4));	// Gamma value times 100000
				$gAMA /= 100000;

			}

			if ($gAMA) { $gamma_correction = 1/$gAMA; }

			// Don't need to apply gamma correction if == default i.e. 2.2
			if ($gamma_correction > 2.15 && $gamma_correction < 2.25) { $gamma_correction = 0; }

			if ($gamma_correction) { echo 'Gamma correction detected'. '<br />';  }

			// NOT supported at present
			if (strpos($data,'sRGB')!==false)	echo 'sRGB colorspace - NOT supported at present'. '<br />';
			if (strpos($data,'cHRM')!==false)	echo 'Chromaticity and Whitepoint - NOT supported at present'. '<br />';

		}

		else {	// PNG image with no need to convert alpha channels, bpc <> 8 etc.
			//Scan chunks looking for palette, transparency and image data
			$pal='';
			$trns='';
			$pngdata='';
			$icc = false;
			$p = 33;
			do {
				$n=_fourbytes2int(substr($data,$p,4));	$p += 4;
				$type=substr($data,$p,4);	$p += 4;
				if ($type=='PLTE') {
					//Read palette
					$pal=substr($data,$p,$n);	$p += $n;
					$p += 4;
				}
				else if($type=='tRNS') {
					//Read transparency info
					$t=substr($data,$p,$n);	$p += $n;
					if ($ct==0) $trns=array(ord(substr($t,1,1)));
					else if ($ct==2) $trns=array(ord(substr($t,1,1)),ord(substr($t,3,1)),ord(substr($t,5,1)));
					else {
						$pos=strpos($t,chr(0));
						if(is_int($pos)) $trns=array($pos);
					}
					$p += 4;
				}
				else if ($type=='IDAT') {
					$pngdata.=substr($data,$p,$n);	$p += $n;
					$p += 4;
				}
				else if ($type=='iCCP') {
					$nullsep = strpos(substr($data,$p,80), chr(0));
					$icc = substr($data, ($p+$nullsep+2), ($n-($nullsep+2)) );
					// Test if file is gzcompressed
					if (ord(substr($str, 0, 1)) == 0x1f && ord(substr($str, 1, 1)) == 0x8b) {
						$icc = @gzuncompress($icc);	// Ignored if fails
					}
					if ($icc) {
					echo 'ICC profile present' . '<br />';
						if (substr($icc, 36, 4) != 'acsp') { echo 'ICC profile INVALID (no acsp flag)' . '<br />'; $icc = false; }	// invalid ICC profile
						else {
							$input = substr($icc, 16, 4);
							$output = substr($icc, 20, 4);
							echo 'ICC profile Input: ' . $input. '<br />';
							echo 'ICC profile Output: ' . $output. '<br />';
							// Ignore Color profiles for conversion to other colorspaces e.g. CMYK/Lab
							if ($input != 'RGB ' || $output != 'XYZ ') { $icc = false; echo 'ICC profile ignored by mPDF' . '<br />'; }
						}
					}
					$p += $n;
					$p += 4;
				}


				else if($type=='IEND') { break; }
				else if (preg_match('/[a-zA-Z]{4}/',$type)) { $p += $n+4; }
				else { echo 'Error parsing PNG image data<br />'; }
			}
			while($n);
			if (!$pngdata) { echo 'Error parsing PNG image data - no IDAT data found<br />';}
			if ($colspace=='Indexed' && empty($pal)) { echo 'Error parsing PNG image data - missing colour palette<br />'; }
			echo 'PNG Image parsed directly' . '<br />';

		}


	}

	// GIF
	else if ($type == 'gif') {
	}

	// BMP (Windows Bitmap)
	else if ($type == 'bmp') {
	}
	// WMF
	else if ($type == 'wmf') {
	}
	// UNKNOWN TYPE - try GD imagecreatefromstring
	else {
		if (function_exists('gd_info')) { $gd = gd_info(); }
		else {$gd = array(); }
		if (isset($gd['PNG Support']) && $gd['PNG Support']) {
			$im = @imagecreatefromstring($data);
			if ($im) { echo 'Image type not recognised, but image created from file using GD imagecreate' . '<br />'; }
			else { echo 'Error parsing image file - image type not recognised, and not supported by GD imagecreate' . '<br />'; }
		}
	}


exit;

//==============================================================

function _fourbytes2int($s) {
	//Read a 4-byte integer from string
	return (ord($s[0])<<24) + (ord($s[1])<<16) + (ord($s[2])<<8) + ord($s[3]);
}

function _twobytes2int($s) {	// equivalent to _get_ushort
	//Read a 2-byte integer from string
	return (ord(substr($s, 0, 1))<<8) + ord(substr($s, 1, 1));
}

function _jpgHeaderFromString(&$data) {
	$p = 4;
	$p += _twobytes2int(substr($data, $p, 2));	// Length of initial marker block
	$marker = substr($data, $p, 2);
	while($marker != chr(255).chr(192) && $marker != chr(255).chr(194) && $p<strlen($data)) {
		// Start of frame marker (FFC0) or (FFC2) mPDF 4.4.004
		$p += (_twobytes2int(substr($data, $p+2, 2))) + 2;	// Length of marker block
		$marker = substr($data, $p, 2);
	}
	if ($marker != chr(255).chr(192) && $marker != chr(255).chr(194)) { return false; }
	return substr($data, $p+2, 10);
}

function _jpgDataFromHeader($hdr) {
	$bpc = ord(substr($hdr, 2, 1));
	if (!$bpc) { $bpc = 8; }
	$h = _twobytes2int(substr($hdr, 3, 2));
	$w = _twobytes2int(substr($hdr, 5, 2));
	$channels = ord(substr($hdr, 7, 1));
	if ($channels==3) { $colspace='DeviceRGB'; }
	elseif($channels==4) { $colspace='DeviceCMYK'; }
	else { $colspace='DeviceGray'; }
	return array($w, $h, $colspace, $bpc, $channels);
}

function file_get_contents_by_curl($url, &$data) {
	$timeout = 5;
	$ch = curl_init($url);
	curl_setopt($ch, CURLOPT_HEADER, 0);
	curl_setopt($ch, CURLOPT_NOBODY, 0);
	curl_setopt ( $ch , CURLOPT_RETURNTRANSFER , 1 );
	curl_setopt ( $ch , CURLOPT_CONNECTTIMEOUT , $timeout );
	$data = curl_exec($ch);
	curl_close($ch);
}


function file_get_contents_by_socket($url, &$data) {
	// mPDF 5.7.3
	$timeout = 1;
	$p = parse_url($url);
	$file = $p['path'];
	if ($p['scheme']=='https') {
		$prefix = 'ssl://';
		$port = ($p['port'] ? $p['port'] : 443);
	}
	else {
		$prefix = '';
		$port = ($p['port'] ? $p['port'] : 80);
	}
	if ($p['query']) { $file .= '?'.$p['query']; }
	if(!($fh = @fsockopen($prefix.$p['host'], $port, $errno, $errstr, $timeout))) { return false; }

	$getstring =
		"GET ".$file." HTTP/1.0 \r\n" .
		"Host: ".$p['host']." \r\n" .
		"Connection: close\r\n\r\n";
	fwrite($fh, $getstring);
	// Get rid of HTTP header
	$s = fgets($fh, 1024);
	if (!$s) { return false; }
	$httpheader .= $s;
	while (!feof($fh)) {
		$s = fgets($fh, 1024);
		if ( $s == "\r\n" ) { break; }
	}
	$data = '';
	while (!feof($fh)) {
		$data .= fgets($fh, 1024);
	}
	fclose($fh);
}

//==============================================================

function _imageTypeFromString(&$data) {
	$type = '';
	if (substr($data, 6, 4)== 'JFIF' || substr($data, 6, 4)== 'Exif' || substr($data, 0, 2)== chr(255).chr(216)) { // 0xFF 0xD8
		$type = 'jpeg';
	}
	else if (substr($data, 0, 6)== "GIF87a" || substr($data, 0, 6)== "GIF89a") {
		$type = 'gif';
	}
	else if (substr($data, 0, 8)== chr(137).'PNG'.chr(13).chr(10).chr(26).chr(10)) {
		$type = 'png';
	}
/*-- IMAGES-WMF --*/
	else if (substr($data, 0, 4)== chr(215).chr(205).chr(198).chr(154)) {
		$type = 'wmf';
	}
/*-- END IMAGES-WMF --*/
	else if (preg_match('/<svg.*<\/svg>/is',$data)) {
		$type = 'svg';
	}
	// BMP images
	else if (substr($data, 0, 2)== "BM") {
		$type = 'bmp';
	}
	return $type;
}