Thumbnails in PHP erstellen

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  • Hier erfahrt ihr wie ihr Vorschaubilder in PHP erstellt, speichert oder "on the fly" anzeigt.
    == Thumbnail Klasse ==

    Quellcode

    1. <?php
    3. /**
    4. * Generates a thumbnail of given source file image.
    5. *
    6. * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
    7. */
    8. class Thumbnail {
    9. /**
    10. * path to source file
    11. *
    12. * @var string
    13. */
    14. protected $sourceFile = '';
    16. /**
    17. * maximum image width
    18. *
    19. * @var integer
    20. */
    21. protected $maxWidth = 100;
    23. /**
    24. * maximum image height
    25. *
    26. * @var integer
    27. */
    28. protected $maxHeight = 100;
    30. /**
    31. * true, to show source information in thumbnail
    32. *
    33. * @var boolean
    34. */
    35. protected $appendSourceInfo = false;
    37. /**
    38. * true, to prefer embedded thumbnails
    39. *
    40. * @var boolean
    41. */
    42. protected $useEmbedded = true;
    44. /**
    45. * true, to generate quadratic thumbnails
    46. *
    47. * @var boolean
    48. */
    49. protected $quadratic = false;
    51. /**
    52. * mime type of the thumbnail
    53. *
    54. * @var string
    55. */
    56. protected $mimeType = '';
    58. /**
    59. * name of the source image
    60. *
    61. * @var string
    62. */
    63. protected $sourceName = '';
    65. /**
    66. * width of the source image
    67. *
    68. * @var integer
    69. */
    70. protected $sourceWidth = 0;
    72. /**
    73. * height of the source image
    74. *
    75. * @var integer
    76. */
    77. protected $sourceHeight = 0;
    79. /**
    80. * file size of the source image
    81. *
    82. * @var integer
    83. */
    84. protected $sourceSize = 0;
    86. /**
    87. * height of the source information
    88. *
    89. * @var integer
    90. */
    91. protected static $sourceInfoLineHeight = 16;
    93. /**
    94. * image type of the source image
    95. *
    96. * @var integer
    97. */
    98. protected $imageType = 0;
    100. /**
    101. * Creates a new Thumbnail object.
    102. *
    103. * @param string $sourceFile
    104. */
    105. public function __construct($sourceFile) {
    106. $this->sourceFile = $sourceFile;
    107. }
    109. /**
    110. * setup dimenstions
    111. *
    112. * @param boolean $appendSourceInfo
    113. */
    114. public function setup($appendSourceInfo = false, $sourceName = null, $useEmbedded = true, $quadratic = false) {
    115. $this->appendSourceInfo = $appendSourceInfo;
    116. $this->useEmbedded = $useEmbedded;
    117. $this->quadratic = $quadratic;
    118. if ($this->appendSourceInfo) {
    119. // get source info
    120. if ($sourceName != null) $this->sourceName = $sourceName;
    121. else $this->sourceName = basename($this->sourceFile);
    122. list($this->sourceWidth, $this->sourceHeight, $type) = @getImageSize($this->sourceFile);
    123. $this->sourceSize = @filesize($sourceFile);
    124. }
    125. }
    127. /**
    128. * Creates a thumbnail picture (jpg/png) of a big image
    129. *
    130. * @param boolean $rescale
    131. * @return string thumbnail
    132. */
    133. protected function makeThumbnail($rescale = false) {
    134. list($width, $height, $this->imageType) = @getImageSize($this->sourceFile);
    136. // check image size
    137. if ($this->checkSize($width, $height, $rescale)) {
    138. return false;
    139. }
    141. // try to extract the embedded thumbnail first (faster)
    142. $thumbnail = false;
    143. if (!$rescale && $this->useEmbedded) {
    144. $thumbnail = $this->extractEmbeddedThumbnail();
    145. }
    146. if (!$thumbnail) {
    147. // calculate uncompressed filesize
    148. // and cancel to avoid a memory_limit error
    149. $memoryLimit = ini_get('memory_limit');
    150. if ($memoryLimit != '') {
    151. $memoryLimit = substr($memoryLimit, 0, -1) * 1024 * 1024;
    152. $fileSize = $width * $height * ($this->imageType == 3 ? 4 : 3);
    154. if (($fileSize * 2.1) + memory_get_usage() > ($memoryLimit)) {
    155. return false;
    156. }
    157. }
    159. // calculate new picture size
    160. $x = $y = 0;
    161. if ($this->quadratic) {
    162. $newWidth = $newHeight = $this->maxWidth;
    163. if ($this->appendSourceInfo) $newHeight -= self::$sourceInfoLineHeight * 2;
    165. if ($width > $height) {
    166. $x = ceil(($width - $height) / 2);
    167. $width = $height;
    168. }
    169. else {
    170. $y = ceil(($height - $width) / 2);
    171. $height = $width;
    172. }
    173. }
    174. else {
    175. $maxHeight = $this->maxHeight;
    176. if ($this->appendSourceInfo) $maxHeight -= self::$sourceInfoLineHeight * 2;
    177. if ($this->maxWidth / $width < $maxHeight / $height) {
    178. $newWidth = $this->maxWidth;
    179. $newHeight = round($height * ($newWidth / $width));
    180. }
    181. else {
    182. $newHeight = $maxHeight;
    183. $newWidth = round($width * ($newHeight / $height));
    184. }
    185. }
    187. // resize image
    188. $imageResource = false;
    190. // jpeg image
    191. if ($this->imageType == 2 && function_exists('imagecreatefromjpeg')) {
    192. $imageResource = @imageCreateFromJPEG($this->sourceFile);
    193. }
    194. // gif image
    195. if ($this->imageType == 1 && function_exists('imagecreatefromgif')) {
    196. $imageResource = @imageCreateFromGIF($this->sourceFile);
    197. }
    198. // png image
    199. if ($this->imageType == 3 && function_exists('imagecreatefrompng')) {
    200. $imageResource = @imageCreateFromPNG($this->sourceFile);
    201. }
    203. // could not create image
    204. if (!$imageResource) {
    205. return false;
    206. }
    208. // resize image
    209. if (function_exists('imageCreateTrueColor') && function_exists('imageCopyResampled')) {
    210. $imageNew = @imageCreateTrueColor($newWidth, $newHeight);
    211. imageAlphaBlending($imageNew, false);
    212. @imageCopyResampled($imageNew, $imageResource, 0, 0, $x, $y, $newWidth, $newHeight, $width, $height);
    213. imageSaveAlpha($imageNew, true);
    214. }
    215. else if (function_exists('imageCreate') && function_exists('imageCopyResized')) {
    216. $imageNew = @imageCreate($newWidth, $newHeight);
    217. imageAlphaBlending($imageNew, false);
    218. @imageCopyResized($imageNew, $imageResource, 0, 0, $x, $y, $newWidth, $newHeight, $width, $height);
    219. imageSaveAlpha($imageNew, true);
    220. }
    221. else return false;
    223. // create thumbnail
    224. ob_start();
    226. if ($this->imageType == 1 && function_exists('imageGIF')) {
    227. @imageGIF($imageNew);
    228. $this->mimeType = 'image/gif';
    229. }
    230. else if (($this->imageType == 1 || $this->imageType == 3) && function_exists('imagePNG')) {
    231. @imagePNG($imageNew);
    232. $this->mimeType = 'image/png';
    233. }
    234. else if (function_exists('imageJPEG')) {
    235. @imageJPEG($imageNew, '', 90);
    236. $this->mimeType = 'image/jpeg';
    237. }
    238. else {
    239. return false;
    240. }
    242. @imageDestroy($imageNew);
    243. $thumbnail = ob_get_contents();
    244. ob_end_clean();
    245. }
    247. if ($thumbnail && $this->appendSourceInfo && !$rescale) {
    248. $thumbnail = $this->appendSourceInfo($thumbnail);
    249. }
    251. return $thumbnail;
    252. }
    254. /**
    255. * Appends information about the source image to the thumbnail.
    256. *
    257. * @param string $thumbnail
    258. * @return string
    259. */
    260. protected function appendSourceInfo($thumbnail) {
    261. if (!function_exists('imageCreateFromString') || !function_exists('imageCreateTrueColor')) {
    262. return $thumbnail;
    263. }
    265. $imageSrc = imageCreateFromString($thumbnail);
    267. // get image size
    268. $width = imageSX($imageSrc);
    269. $height = imageSY($imageSrc);
    271. // increase height
    272. $heightDst = $height + self::$sourceInfoLineHeight * 2;
    274. // create new image
    275. $imageDst = imageCreateTrueColor($width, $heightDst);
    276. imageAlphaBlending($imageDst, false);
    278. // set background color
    279. $background = imageColorAllocate($imageDst, 102, 102, 102);
    280. imageFill($imageDst, 0, 0, $background);
    282. // copy image
    283. imageCopy($imageDst, $imageSrc, 0, 0, 0, 0, $width, $height);
    284. imageSaveAlpha($imageDst, true);
    286. // get font size
    287. $font = 2;
    288. $fontWidth = imageFontWidth($font);
    289. $fontHeight = imageFontHeight($font);
    290. $fontColor = imageColorAllocate($imageDst, 255, 255, 255);
    292. // write source info
    293. if($maxWidth) $this->maxWidth = $maxWidth;
    294. if($maxHeight) $this->maxHeight = $maxHeight;
    295. $line1 = $this->sourceName;
    297. // imageString supports only ISO-8859-1 encoded strings
    298. // if (CHARSET != 'ISO-8859-1') {
    299. // $line1 = StringUtil::convertEncoding(CHARSET, 'ISO-8859-1', $line1);
    300. // }
    302. // truncate text if necessary
    303. $maxChars = floor($width / $fontWidth);
    304. if (strlen($line1) > $maxChars) {
    305. $line1 = $this->truncateSourceName($line1, $maxChars);
    306. }
    308. $line2 = $this->sourceWidth.'x'.$this->sourceHeight;
    310. // write line 1
    311. // calculate text position
    312. $textX = 0;
    313. $textY = 0;
    315. if ($fontHeight < self::$sourceInfoLineHeight) {
    316. $textY = intval(round((self::$sourceInfoLineHeight - $fontHeight) / 2));
    317. }
    318. if (strlen($line1) * $fontWidth < $width) {
    319. $textX = intval(round(($width - strlen($line1) * $fontWidth) / 2));
    320. }
    322. imageString($imageDst, $font, $textX, $height + $textY, $line1, $fontColor);
    324. // write line 2
    325. // calculate text position
    326. $textX = 0;
    327. $textY = 0;
    329. if ($fontHeight < self::$sourceInfoLineHeight) {
    330. $textY = self::$sourceInfoLineHeight + intval(round((self::$sourceInfoLineHeight - $fontHeight) / 2));
    331. }
    332. if (strlen($line2) * $fontWidth < $width) {
    333. $textX = intval(round(($width - strlen($line2) * $fontWidth) / 2));
    334. }
    336. imageString($imageDst, $font, $textX, $height + $textY, $line2, $fontColor);
    339. // output image
    340. ob_start();
    342. if ($this->imageType == 1 && function_exists('imageGIF')) {
    343. @imageGIF($imageDst);
    344. $this->mimeType = 'image/gif';
    345. }
    346. else if (($this->imageType == 1 || $this->imageType == 3) && function_exists('imagePNG')) {
    347. @imagePNG($imageDst);
    348. $this->mimeType = 'image/png';
    349. }
    350. else if (function_exists('imageJPEG')) {
    351. @imageJPEG($imageDst, '', 90);
    352. $this->mimeType = 'image/jpeg';
    353. }
    354. else {
    355. return false;
    356. }
    358. @imageDestroy($imageDst);
    359. $thumbnail = ob_get_contents();
    360. ob_end_clean();
    362. return $thumbnail;
    363. }
    366. /**
    367. * Extracts the embedded thumbnail picture of a jpeg or tiff image
    368. *
    369. * @return string thumbnail
    370. */
    371. protected function extractEmbeddedThumbnail() {
    372. if (!function_exists('exif_thumbnail')) {
    373. return false;
    374. }
    376. $width = $height = $type = 0;
    377. $thumbnail = @exif_thumbnail($this->sourceFile, $width, $height, $type);
    378. if ($thumbnail && $type && $width && $height) {
    379. // resize the extracted thumbnail again if necessary
    380. // (normally the thumbnail size is set to 160px
    381. // which is recommended in EXIF >2.1 and DCF)
    382. $this->mimeType = image_type_to_mime_type($type);
    383. if (!$this->checkSize($width, $height) && function_exists('sys_get_temp_dir')) {
    384. // get temporary file name
    385. $this->sourceFile = tempnam(sys_get_temp_dir(), 'Tux');
    387. // create tmp file
    388. $fh = fopen($this->sourceFile, "w");
    389. fwrite($fh, $thumbnail);
    390. fclose($fh);
    391. unset($thumbnail, $tmpFile);
    393. // resize tmp file again
    394. return $this->makeThumbnail(true);
    395. }
    397. return $thumbnail;
    398. }
    400. return false;
    401. }
    403. /**
    404. * Checks the size of an image.
    405. */
    406. protected function checkSize($width, $height, $rescale = true) {
    407. $maxHeight = $this->maxHeight;
    408. if ($this->appendSourceInfo && $rescale) {
    409. $maxHeight -= self::$sourceInfoLineHeight * 2;
    410. }
    412. if ($width > $this->maxWidth || $height > $maxHeight) {
    413. return false;
    414. }
    416. return true;
    417. }
    419. /**
    420. * Returns the mime type of the generated thumbnail.
    421. *
    422. * @return string
    423. */
    424. public function getMimeType() {
    425. return $this->mimeType;
    426. }
    428. /**
    429. * Truncates the given file name to needed length.
    430. *
    431. * @param string $name
    432. * @param string $maxChars
    433. * @return string
    434. */
    435. protected static function truncateSourceName($name, $maxChars) {
    436. $extension = '';
    437. $lastPosition = strrpos($name, '.');
    438. if ($lastPosition !== null) {
    439. $extension = substr($name, $lastPosition);
    440. $name = substr($name, 0, $lastPosition);
    441. $maxChars -= strlen($extension);
    442. }
    444. return substr($name, 0, $maxChars - 3) . '...' . $extension;
    445. }
    447. /**
    448. *
    449. * @return boolean
    450. */
    451. public function save($targetFile, $maxWidth = 0, $maxHeight = 0) {
    452. $recover = array();
    453. if($maxWidth) {
    454. $recover['maxWidth'] = $this->maxWidth;
    455. $this->maxWidth = $maxWidth;
    456. }
    457. if($maxHeight) {
    458. $recover['maxHeight'] = $this->maxHeight;
    459. $this->maxHeight = $maxHeight;
    460. }
    462. // get thumbnail
    463. try {
    464. $success = true;
    465. if (($thumbnailData = $this->makeThumbnail())) {
    467. // save thumbnail
    468. $fh = fopen($targetFile, 'w');
    469. fwrite($fh, $thumbnailData);
    470. unset($thumbnailData);
    471. fclose($fh);
    472. }
    473. }
    474. catch (Exception $e) {
    475. $success = false;
    476. }
    478. foreach($recover as $key => $val) {
    479. $this->$key = $val;
    480. }
    481. return $success;
    482. }
    484. protected static function sendLastModified($timestamp) {
    485. // Getting headers sent by the client.
    486. $headers = apache_request_headers();
    488. // Checking if the client is validating his cache and if it is current.
    489. if (isset($headers['If-Modified-Since']) && (strtotime($headers['If-Modified-Since']) >= $timestamp)) {
    490. // this timestamp can also be used to identify the user ;) see
    491. // Client's cache IS current, so we just respond '304 Not Modified'.
    492. header('Last-Modified: '.gmdate('D, d M Y H:i:s', $timestamp).' GMT', true, 304);
    493. exit;
    494. } else {
    495. // Image not cached or cache outdated, we respond '200 OK' and output the image.
    496. header('Last-Modified: '.gmdate('D, d M Y H:i:s', $timestamp).' GMT', true, 200);
    497. }
    498. }
    500. /**
    501. * send header and content for the picture
    502. */
    503. public function display($maxWidth = 100, $maxHeight = 100, $age = '3 MONTH') {
    504. $recover = array();
    505. if($maxWidth) {
    506. $recover['maxWidth'] = $this->maxWidth;
    507. $this->maxWidth = $maxWidth;
    508. }
    509. if($maxHeight) {
    510. $recover['maxHeight'] = $this->maxHeight;
    511. $this->maxHeight = $maxHeight;
    512. }
    514. $filemtime = @filemtime($this->sourceFile);
    515. $thumbnailData = $this->makeThumbnail();
    516. $size = strlen($thumbnailData);
    518. self::sendLastModified($filemtime);
    519. header('Accept-Ranges: bytes');
    520. header('Content-Length: '.$size);
    521. header('Content-Type: image/jpeg');
    522. header('Expires: '.gmdate('D, d M Y H:i:s', time() + strtotime($age)).' GMT');
    524. echo $thumbnailData;
    526. foreach($recover as $key => $val) {
    527. $this->$key = $val;
    528. }
    529. }
    530. }
    531. ?>
    Alles anzeigen


    == Beispiele ==
    === Bild in meheren Größen speichern ===

    Quellcode

    1. <?php
    2. require_once('Thumbnail.php');
    4. // this is the source
    5. $thumb = new Thumbnail('demo/easy-coding.png');
    7. // quadratic
    8. $thumb->save('/tmp/easy-coding.png', 150, 150);
    10. // 4:3 format
    11. $thumb->save('/tmp/easy-coding.png', 100, 75);
    13. ?>
    Alles anzeigen


    == Bild "on the fly" anzeigen ==
    Den Original Bildnamen könnt ihr zum Beispiel als $_GET Parameter oder mit mod_rewrite Regeln durchleiten. Im Beispiel wird die Vorschau für das Bild "easy-coding.png" erzeugt.
    Der dritte Parameter der Methode display kann einen Zeitausdruck wie "3 month" enthalten, dann wird das Bild für drei Monate im Browser Cache des Benutzers gespeichert, ohne dass es erneut angefragt wird und damit Traffickosten verursacht. Allerdings bekommt der Benutzer auf diese Weise auch nicht von Änderungen mit, deswegen sollte der Intervall je nach Anwendung besser bei "1 day" liegen.

    Quellcode

    1. <?php
    2. require_once('Thumbnail.php');
    4. $thumb = new Thumbnail('demo/easy-coding.png');
    6. // just display on the fly
    7. $thumb->display(150, 150);


    == Demo ==
    Die Live Demo findet ihr unter demo.easy-coding.de/php/thumbnail/, herunterladen könnt ihr euch den Code dann unter demo.easy-coding.de/php/thumbnail/download.zip

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