<?php /* PROJECT INFO -------------------------------------------------------------------------------------------------------- Version: 1.5.2 Changelog: http://adaptive-images.com/changelog.txt Homepage: http://adaptive-images.com GitHub: https://github.com/MattWilcox/Adaptive-Images Twitter: @responsiveimg LEGAL: Adaptive Images by Matt Wilcox is licensed under a Creative Commons Attribution 3.0 Unported License. /* CONFIG ----------------------------------------------------------------------------------------------------------- */ $resolutions = array(1382, 992, 768, 480); // the resolution break-points to use (screen widths, in pixels) $cache_path = "ai-cache"; // where to store the generated re-sized images. Specify from your document root! $jpg_quality = 85; // the quality of any generated JPGs on a scale of 0 to 100 $sharpen = TRUE; // Shrinking images can blur details, perform a sharpen on re-scaled images? $watch_cache = TRUE; // check that the adapted image isn't stale (ensures updated source images are re-cached) $browser_cache = 60*60*24*7; // How long the BROWSER cache should last (seconds, minutes, hours, days. 7days by default) /* END CONFIG ---------------------------------------------------------------------------------------------------------- ------------------------ Don't edit anything after this line unless you know what you're doing ------------------------- --------------------------------------------------------------------------------------------------------------------- */ /* get all of the required data from the HTTP request */ $document_root = $_SERVER['DOCUMENT_ROOT']; $requested_uri = parse_url(urldecode($_SERVER['REQUEST_URI']), PHP_URL_PATH); $requested_file = basename($requested_uri); $source_file = $document_root.$requested_uri; $resolution = TRUE; /* Mobile detection NOTE: only used in the event a cookie isn't available. */ function is_mobile() { $userAgent = strtolower($_SERVER['HTTP_USER_AGENT']); return strpos($userAgent, 'mobile'); } /* Does the UA string indicate this is a mobile? */ if(!is_mobile()){ $is_mobile = FALSE; } else { $is_mobile = TRUE; } // does the $cache_path directory exist already? if (!is_dir("$document_root/$cache_path")) { // no if (!mkdir("$document_root/$cache_path", 0755, true)) { // so make it if (!is_dir("$document_root/$cache_path")) { // check again to protect against race conditions // uh-oh, failed to make that directory sendErrorImage("Failed to create cache directory at: $document_root/$cache_path"); } } } /* helper function: Send headers and returns an image. */ function sendImage($filename, $browser_cache) { $extension = strtolower(pathinfo($filename, PATHINFO_EXTENSION)); if (in_array($extension, array('png', 'gif', 'jpeg'))) { header("Content-Type: image/".$extension); } else { header("Content-Type: image/jpeg"); } header("Cache-Control: private, max-age=".$browser_cache); header('Expires: '.gmdate('D, d M Y H:i:s', time()+$browser_cache).' GMT'); header('Content-Length: '.filesize($filename)); readfile($filename); exit(); } /* helper function: Create and send an image with an error message. */ function sendErrorImage($message) { /* get all of the required data from the HTTP request */ $document_root = $_SERVER['DOCUMENT_ROOT']; $requested_uri = parse_url(urldecode($_SERVER['REQUEST_URI']), PHP_URL_PATH); $requested_file = basename($requested_uri); $source_file = $document_root.$requested_uri; if(!is_mobile()){ $is_mobile = "FALSE"; } else { $is_mobile = "TRUE"; } $im = ImageCreateTrueColor(800, 300); $text_color = ImageColorAllocate($im, 233, 14, 91); $message_color = ImageColorAllocate($im, 91, 112, 233); ImageString($im, 5, 5, 5, "Adaptive Images encountered a problem:", $text_color); ImageString($im, 3, 5, 25, $message, $message_color); ImageString($im, 5, 5, 85, "Potentially useful information:", $text_color); ImageString($im, 3, 5, 105, "DOCUMENT ROOT IS: $document_root", $text_color); ImageString($im, 3, 5, 125, "REQUESTED URI WAS: $requested_uri", $text_color); ImageString($im, 3, 5, 145, "REQUESTED FILE WAS: $requested_file", $text_color); ImageString($im, 3, 5, 165, "SOURCE FILE IS: $source_file", $text_color); ImageString($im, 3, 5, 185, "DEVICE IS MOBILE? $is_mobile", $text_color); header("Cache-Control: no-store"); header('Expires: '.gmdate('D, d M Y H:i:s', time()-1000).' GMT'); header('Content-Type: image/jpeg'); ImageJpeg($im); ImageDestroy($im); exit(); } /* sharpen images function */ function findSharp($intOrig, $intFinal) { $intFinal = $intFinal * (750.0 / $intOrig); $intA = 52; $intB = -0.27810650887573124; $intC = .00047337278106508946; $intRes = $intA + $intB * $intFinal + $intC * $intFinal * $intFinal; return max(round($intRes), 0); } /* refreshes the cached image if it's outdated */ function refreshCache($source_file, $cache_file, $resolution) { if (file_exists($cache_file)) { // not modified if (filemtime($cache_file) >= filemtime($source_file)) { return $cache_file; } // modified, clear it unlink($cache_file); } return generateImage($source_file, $cache_file, $resolution); } /* generates the given cache file for the given source file with the given resolution */ function generateImage($source_file, $cache_file, $resolution) { global $sharpen, $jpg_quality; $extension = strtolower(pathinfo($source_file, PATHINFO_EXTENSION)); // Check the image dimensions $dimensions = GetImageSize($source_file); $width = $dimensions[0]; $height = $dimensions[1]; // Do we need to downscale the image? if ($width <= $resolution) { // no, because the width of the source image is already less than the client width return $source_file; } // We need to resize the source image to the width of the resolution breakpoint we're working with $ratio = $height/$width; $new_width = $resolution; $new_height = ceil($new_width * $ratio); $dst = ImageCreateTrueColor($new_width, $new_height); // re-sized image switch ($extension) { case 'png': $src = @ImageCreateFromPng($source_file); // original image break; case 'gif': $src = @ImageCreateFromGif($source_file); // original image break; default: $src = @ImageCreateFromJpeg($source_file); // original image ImageInterlace($dst, true); // Enable interlancing (progressive JPG, smaller size file) break; } if($extension=='png'){ imagealphablending($dst, false); imagesavealpha($dst,true); $transparent = imagecolorallocatealpha($dst, 255, 255, 255, 127); imagefilledrectangle($dst, 0, 0, $new_width, $new_height, $transparent); } ImageCopyResampled($dst, $src, 0, 0, 0, 0, $new_width, $new_height, $width, $height); // do the resize in memory ImageDestroy($src); // sharpen the image? // NOTE: requires PHP compiled with the bundled version of GD (see http://php.net/manual/en/function.imageconvolution.php) if($sharpen == TRUE && function_exists('imageconvolution')) { $intSharpness = findSharp($width, $new_width); $arrMatrix = array( array(-1, -2, -1), array(-2, $intSharpness + 12, -2), array(-1, -2, -1) ); imageconvolution($dst, $arrMatrix, $intSharpness, 0); } $cache_dir = dirname($cache_file); // does the directory exist already? if (!is_dir($cache_dir)) { if (!mkdir($cache_dir, 0755, true)) { // check again if it really doesn't exist to protect against race conditions if (!is_dir($cache_dir)) { // uh-oh, failed to make that directory ImageDestroy($dst); sendErrorImage("Failed to create cache directory: $cache_dir"); } } } if (!is_writable($cache_dir)) { sendErrorImage("The cache directory is not writable: $cache_dir"); } // save the new file in the appropriate path, and send a version to the browser switch ($extension) { case 'png': $gotSaved = ImagePng($dst, $cache_file); break; case 'gif': $gotSaved = ImageGif($dst, $cache_file); break; default: $gotSaved = ImageJpeg($dst, $cache_file, $jpg_quality); break; } ImageDestroy($dst); if (!$gotSaved && !file_exists($cache_file)) { sendErrorImage("Failed to create image: $cache_file"); } return $cache_file; } // check if the file exists at all if (!file_exists($source_file)) { header("Status: 404 Not Found"); exit(); } /* check that PHP has the GD library available to use for image re-sizing */ if (!extension_loaded('gd')) { // it's not loaded if (!function_exists('dl') || !dl('gd.so')) { // and we can't load it either // no GD available, so deliver the image straight up trigger_error('You must enable the GD extension to make use of Adaptive Images', E_USER_WARNING); sendImage($source_file, $browser_cache); } } /* Check to see if a valid cookie exists */ if (isset($_COOKIE['resolution'])) { $cookie_value = $_COOKIE['resolution']; // does the cookie look valid? [whole number, comma, potential floating number] if (! preg_match("/^[0-9]+[,]*[0-9\.]+$/", "$cookie_value")) { // no it doesn't look valid setcookie("resolution", "$cookie_value", time()-100); // delete the mangled cookie } else { // the cookie is valid, do stuff with it $cookie_data = explode(",", $_COOKIE['resolution']); $client_width = (int) $cookie_data[0]; // the base resolution (CSS pixels) $total_width = $client_width; $pixel_density = 1; // set a default, used for non-retina style JS snippet if (@$cookie_data[1]) { // the device's pixel density factor (physical pixels per CSS pixel) $pixel_density = $cookie_data[1]; } rsort($resolutions); // make sure the supplied break-points are in reverse size order $resolution = $resolutions[0]; // by default use the largest supported break-point // if pixel density is not 1, then we need to be smart about adapting and fitting into the defined breakpoints if($pixel_density != 1) { $total_width = $client_width * $pixel_density; // required physical pixel width of the image // the required image width is bigger than any existing value in $resolutions if($total_width > $resolutions[0]){ // firstly, fit the CSS size into a break point ignoring the multiplier foreach ($resolutions as $break_point) { // filter down if ($total_width <= $break_point) { $resolution = $break_point; } } // now apply the multiplier $resolution = $resolution * $pixel_density; } // the required image fits into the existing breakpoints in $resolutions else { foreach ($resolutions as $break_point) { // filter down if ($total_width <= $break_point) { $resolution = $break_point; } } } } else { // pixel density is 1, just fit it into one of the breakpoints foreach ($resolutions as $break_point) { // filter down if ($total_width <= $break_point) { $resolution = $break_point; } } } } } /* No resolution was found (no cookie or invalid cookie) */ if (!$resolution) { // We send the lowest resolution for mobile-first approach, and highest otherwise $resolution = $is_mobile ? min($resolutions) : max($resolutions); } /* if the requested URL starts with a slash, remove the slash */ if(substr($requested_uri, 0,1) == "/") { $requested_uri = substr($requested_uri, 1); } /* whew might the cache file be? */ $cache_file = $document_root."/$cache_path/$resolution/".$requested_uri; /* Use the resolution value as a path variable and check to see if an image of the same name exists at that path */ if (file_exists($cache_file)) { // it exists cached at that size if ($watch_cache) { // if cache watching is enabled, compare cache and source modified dates to ensure the cache isn't stale $cache_file = refreshCache($source_file, $cache_file, $resolution); } sendImage($cache_file, $browser_cache); } /* It exists as a source file, and it doesn't exist cached - lets make one: */ $file = generateImage($source_file, $cache_file, $resolution); sendImage($file, $browser_cache);