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一个很实用的类,php调整gif图片的尺寸！

程序员文章站 2022-05-21 11:02:24
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这个类可以对GIF格式的动态文件进行调整。提取动态图片帧文件到一个临时目录中。调整图像的大小并提取和重建成动画的GIF格式的新文件。

@红薯不让传gif图片
效果查看:http://www.codepearl.com/files/187.html 一个很实用的类,php调整gif图片的尺寸！
  2. //http://www.codepearl.com
  3. require_once "gifresizer.php";
  4. $gr = new gifresizer;
  5. $gr->temp_dir = "codepearl";
  6. $gr->resize("codepearl.gif","codepearl_resized.gif",500,500);
  7. ?>
复制代码
  2. /**
  3. * http://www.codepearl.com
  4. * Resizes Animated GIF Files
  5. *
  6. * ///IMPORTANT NOTE: The script needs a temporary directory where all the frames should be extracted.
  7. * Create a directory with a 777 permission level and write the path into $temp_dir variable below.
  8. *
  9. * Default directory is "frames".
  10. */
  12. class gifresizer {
  14. public $temp_dir = "frames";
  15. private $pointer = 0;
  16. private $index = 0;
  17. private $globaldata = array();
  18. private $imagedata = array();
  19. private $imageinfo = array();
  20. private $handle = 0;
  21. private $orgvars = array();
  22. private $encdata = array();
  23. private $parsedfiles = array();
  24. private $originalwidth = 0;
  25. private $originalheight = 0;
  26. private $wr,$hr;
  27. private $props = array();
  28. private $decoding = false;
  30. /**
  31. * Public part of the class
  32. *
  33. * @orgfile - Original file path
  34. * @newfile - New filename with path
  35. * @width - Desired image width
  36. * @height - Desired image height
  37. */
  38. function resize($orgfile,$newfile,$width,$height){
  39. $this->decode($orgfile);
  40. $this->wr=$width/$this->originalwidth;
  41. $this->hr=$height/$this->originalheight;
  42. $this->resizeframes();
  43. $this->encode($newfile,$width,$height);
  44. $this->clearframes();
  45. }
  47. /**
  48. * GIF Decoder function.
  49. * Parses the GIF animation into single frames.
  50. */
  51. private function decode($filename){
  52. $this->decoding = true;
  53. $this->clearvariables();
  54. $this->loadfile($filename);
  55. $this->get_gif_header();
  56. $this->get_graphics_extension(0);
  57. $this->get_application_data();
  58. $this->get_application_data();
  59. $this->get_image_block(0);
  60. $this->get_graphics_extension(1);
  61. $this->get_comment_data();
  62. $this->get_application_data();
  63. $this->get_image_block(1);
  64. while(!$this->checkbyte(0x3b) && !$this->checkEOF()){
  65. $this->get_comment_data(1);
  66. $this->get_graphics_extension(2);
  67. $this->get_image_block(2);
  68. }
  69. $this->writeframes(time());
  70. $this->closefile();
  71. $this->decoding = false;
  72. }
  74. /**
  75. * GIF Encoder function.
  76. * Combines the parsed GIF frames into one single animation.
  77. */
  78. private function encode($new_filename,$newwidth,$newheight){
  79. $mystring = "";
  80. $this->pointer = 0;
  81. $this->imagedata = array();
  82. $this->imageinfo = array();
  83. $this->handle = 0;
  84. $this->index=0;
  86. $k=0;
  87. foreach($this->parsedfiles as $imagepart){
  88. $this->loadfile($imagepart);
  89. $this->get_gif_header();
  90. $this->get_application_data();
  91. $this->get_comment_data();
  92. $this->get_graphics_extension(0);
  93. $this->get_image_block(0);
  95. //get transparent color index and color
  96. if(isset($this->encdata[$this->index-1]))
  97. $gxdata = $this->encdata[$this->index-1]["graphicsextension"];
  98. else
  99. $gxdata = null;
  100. $ghdata = $this->imageinfo["gifheader"];
  101. $trcolor = "";
  102. $hastransparency=($gxdata[3]&&1==1);
  104. if($hastransparency){
  105. $trcx = ord($gxdata[6]);
  106. $trcolor = substr($ghdata,13+$trcx*3,3);
  107. }
  109. //global color table to image data;
  110. $this->transfercolortable($this->imageinfo["gifheader"],$this->imagedata[$this->index-1]["imagedata"]);
  112. $imageblock = &$this->imagedata[$this->index-1]["imagedata"];
  114. //if transparency exists transfer transparency index
  115. if($hastransparency){
  116. $haslocalcolortable = ((ord($imageblock[9])&128)==128);
  117. if($haslocalcolortable){
  118. //local table exists. determine boundaries and look for it.
  119. $tablesize=(pow(2,(ord($imageblock[9])&7)+1)*3)+10;
  120. $this->orgvars[$this->index-1]["transparent_color_index"] =
  121. ((strrpos(substr($this->imagedata[$this->index-1]["imagedata"],0,$tablesize),$trcolor)-10)/3);
  122. }else{
  123. //local table doesnt exist, look at the global one.
  124. $tablesize=(pow(2,(ord($gxdata[10])&7)+1)*3)+10;
  125. $this->orgvars[$this->index-1]["transparent_color_index"] =
  126. ((strrpos(substr($ghdata,0,$tablesize),$trcolor)-10)/3);
  127. }
  128. }
  130. //apply original delay time,transparent index and disposal values to graphics extension
  132. if(!$this->imagedata[$this->index-1]["graphicsextension"]) $this->imagedata[$this->index-1]["graphicsextension"] = chr(0x21).chr(0xf9).chr(0x04).chr(0x00).chr(0x00).chr(0x00).chr(0x00).chr(0x00);
  134. $imagedata = &$this->imagedata[$this->index-1]["graphicsextension"];
  136. $imagedata[3] = chr((ord($imagedata[3]) & 0xE3) | ($this->orgvars[$this->index-1]["disposal_method"] $imagedata[4] = chr(($this->orgvars[$this->index-1]["delay_time"] % 256));
  137. $imagedata[5] = chr(floor($this->orgvars[$this->index-1]["delay_time"] / 256));
  138. if($hastransparency){
  139. $imagedata[6] = chr($this->orgvars[$this->index-1]["transparent_color_index"]);
  140. }
  141. $imagedata[3] = chr(ord($imagedata[3])|$hastransparency);
  143. //apply calculated left and top offset
  144. $imageblock[1] = chr(round(($this->orgvars[$this->index-1]["offset_left"]*$this->wr) % 256));
  145. $imageblock[2] = chr(floor(($this->orgvars[$this->index-1]["offset_left"]*$this->wr) / 256));
  146. $imageblock[3] = chr(round(($this->orgvars[$this->index-1]["offset_top"]*$this->hr) % 256));
  147. $imageblock[4] = chr(floor(($this->orgvars[$this->index-1]["offset_top"]*$this->hr) / 256));
  149. if($this->index==1){
  150. if(!isset($this->imageinfo["applicationdata"]) || !$this->imageinfo["applicationdata"])
  151. $this->imageinfo["applicationdata"]=chr(0x21).chr(0xff).chr(0x0b)."NETSCAPE2.0".chr(0x03).chr(0x01).chr(0x00).chr(0x00).chr(0x00);
  152. if(!isset($this->imageinfo["commentdata"]) || !$this->imageinfo["commentdata"])
  153. $this->imageinfo["commentdata"] = chr(0x21).chr(0xfe).chr(0x10)."PHPGIFRESIZER1.0".chr(0);
  154. $mystring .= $this->orgvars["gifheader"]. $this->imageinfo["applicationdata"].$this->imageinfo["commentdata"];
  155. if(isset($this->orgvars["hasgx_type_0"]) && $this->orgvars["hasgx_type_0"]) $mystring .= $this->globaldata["graphicsextension_0"];
  156. if(isset($this->orgvars["hasgx_type_1"]) && $this->orgvars["hasgx_type_1"]) $mystring .= $this->globaldata["graphicsextension"];
  157. }
  159. $mystring .= $imagedata . $imageblock;
  160. $k++;
  161. $this->closefile();
  162. }
  164. $mystring .= chr(0x3b);
  166. //applying new width & height to gif header
  167. $mystring[6] = chr($newwidth % 256);
  168. $mystring[7] = chr(floor($newwidth / 256));
  169. $mystring[8] = chr($newheight % 256);
  170. $mystring[9] = chr(floor($newheight / 256));
  171. $mystring[11]= $this->orgvars["background_color"];
  172. //if(file_exists($new_filename)){unlink($new_filename);}
  173. file_put_contents($new_filename,$mystring);
  174. }
  176. /**
  177. * Variable Reset function
  178. * If a instance is used multiple times, it's needed. Trust me.
  179. */
  180. private function clearvariables(){
  181. $this->pointer = 0;
  182. $this->index = 0;
  183. $this->imagedata = array();
  184. $this->imageinfo = array();
  185. $this->handle = 0;
  186. $this->parsedfiles = array();
  187. }
  189. /**
  190. * Clear Frames function
  191. * For deleting the frames after encoding.
  192. */
  193. private function clearframes(){
  194. foreach($this->parsedfiles as $temp_frame){
  195. unlink($temp_frame);
  196. }
  197. }
  199. /**
  200. * Frame Writer
  201. * Writes the GIF frames into files.
  202. */
  203. private function writeframes($prepend){
  204. for($i=0;$iimagedata);$i++){
  205. file_put_contents($this->temp_dir."/frame_".$prepend."_".str_pad($i,2,"0",STR_PAD_LEFT).".gif",$this->imageinfo["gifheader"].$this->imagedata[$i]["graphicsextension"].$this->imagedata[$i]["imagedata"].chr(0x3b));
  206. $this->parsedfiles[]=$this->temp_dir."/frame_".$prepend."_".str_pad($i,2,"0",STR_PAD_LEFT).".gif";
  207. }
  208. }
  210. /**
  211. * Color Palette Transfer Device
  212. * Transferring Global Color Table (GCT) from frames into Local Color Tables in animation.
  213. */
  214. private function transfercolortable($src,&$dst){
  215. //src is gif header,dst is image data block
  216. //if global color table exists,transfer it
  217. if((ord($src[10])&128)==128){
  218. //Gif Header Global Color Table Length
  219. $ghctl = pow(2,$this->readbits(ord($src[10]),5,3)+1)*3;
  220. //cut global color table from gif header
  221. $ghgct = substr($src,13,$ghctl);
  222. //check image block color table length
  223. if((ord($dst[9])&128)==128){
  224. //Image data contains color table. skip.
  225. }else{
  226. //Image data needs a color table.
  227. //get last color table length so we can truncate the dummy color table
  228. $idctl = pow(2,$this->readbits(ord($dst[9]),5,3)+1)*3;
  229. //set color table flag and length
  230. $dst[9] = chr(ord($dst[9]) | (0x80 | (log($ghctl/3,2)-1)));
  231. //inject color table
  232. $dst = substr($dst,0,10).$ghgct.substr($dst,-1*strlen($dst)+10);
  233. }
  234. }else{
  235. //global color table doesn't exist. skip.
  236. }
  237. }
  239. /**
  240. * GIF Parser Functions.
  241. * Below functions are the main structure parser components.
  242. */
  243. private function get_gif_header(){
  244. $this->p_forward(10);
  245. if($this->readbits(($mybyte=$this->readbyte_int()),0,1)==1){
  246. $this->p_forward(2);
  247. $this->p_forward(pow(2,$this->readbits($mybyte,5,3)+1)*3);
  248. }else{
  249. $this->p_forward(2);
  250. }
  252. $this->imageinfo["gifheader"]=$this->datapart(0,$this->pointer);
  253. if($this->decoding){
  254. $this->orgvars["gifheader"]=$this->imageinfo["gifheader"];
  255. $this->originalwidth = ord($this->orgvars["gifheader"][7])*256+ord($this->orgvars["gifheader"][6]);
  256. $this->originalheight = ord($this->orgvars["gifheader"][9])*256+ord($this->orgvars["gifheader"][8]);
  257. $this->orgvars["background_color"]=$this->orgvars["gifheader"][11];
  258. }
  260. }
  261. //-------------------------------------------------------
  262. private function get_application_data(){
  263. $startdata = $this->readbyte(2);
  264. if($startdata==chr(0x21).chr(0xff)){
  265. $start = $this->pointer - 2;
  266. $this->p_forward($this->readbyte_int());
  267. $this->read_data_stream($this->readbyte_int());
  268. $this->imageinfo["applicationdata"] = $this->datapart($start,$this->pointer-$start);
  269. }else{
  270. $this->p_rewind(2);
  271. }
  272. }
  273. //-------------------------------------------------------
  274. private function get_comment_data(){
  275. $startdata = $this->readbyte(2);
  276. if($startdata==chr(0x21).chr(0xfe)){
  277. $start = $this->pointer - 2;
  278. $this->read_data_stream($this->readbyte_int());
  279. $this->imageinfo["commentdata"] = $this->datapart($start,$this->pointer-$start);
  280. }else{
  281. $this->p_rewind(2);
  282. }
  283. }
  284. //-------------------------------------------------------
  285. private function get_graphics_extension($type){
  286. $startdata = $this->readbyte(2);
  287. if($startdata==chr(0x21).chr(0xf9)){
  288. $start = $this->pointer - 2;
  289. $this->p_forward($this->readbyte_int());
  290. $this->p_forward(1);
  291. if($type==2){
  292. $this->imagedata[$this->index]["graphicsextension"] = $this->datapart($start,$this->pointer-$start);
  293. }else if($type==1){
  294. $this->orgvars["hasgx_type_1"] = 1;
  295. $this->globaldata["graphicsextension"] = $this->datapart($start,$this->pointer-$start);
  296. }else if($type==0 && $this->decoding==false){
  297. $this->encdata[$this->index]["graphicsextension"] = $this->datapart($start,$this->pointer-$start);
  298. }else if($type==0 && $this->decoding==true){
  299. $this->orgvars["hasgx_type_0"] = 1;
  300. $this->globaldata["graphicsextension_0"] = $this->datapart($start,$this->pointer-$start);
  301. }
  302. }else{
  303. $this->p_rewind(2);
  304. }
  305. }
  306. //-------------------------------------------------------
  307. private function get_image_block($type){
  308. if($this->checkbyte(0x2c)){
  309. $start = $this->pointer;
  310. $this->p_forward(9);
  311. if($this->readbits(($mybyte=$this->readbyte_int()),0,1)==1){
  312. $this->p_forward(pow(2,$this->readbits($mybyte,5,3)+1)*3);
  313. }
  314. $this->p_forward(1);
  315. $this->read_data_stream($this->readbyte_int());
  316. $this->imagedata[$this->index]["imagedata"] = $this->datapart($start,$this->pointer-$start);
  318. if($type==0){
  319. $this->orgvars["hasgx_type_0"] = 0;
  320. if(isset($this->globaldata["graphicsextension_0"]))
  321. $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension_0"];
  322. else
  323. $this->imagedata[$this->index]["graphicsextension"]=null;
  324. unset($this->globaldata["graphicsextension_0"]);
  325. }elseif($type==1){
  326. if(isset($this->orgvars["hasgx_type_1"]) && $this->orgvars["hasgx_type_1"]==1){
  327. $this->orgvars["hasgx_type_1"] = 0;
  328. $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension"];
  329. unset($this->globaldata["graphicsextension"]);
  330. }else{
  331. $this->orgvars["hasgx_type_0"] = 0;
  332. $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension_0"];
  333. unset($this->globaldata["graphicsextension_0"]);
  334. }
  335. }
  337. $this->parse_image_data();
  338. $this->index++;
  340. }
  341. }
  342. //-------------------------------------------------------
  343. private function parse_image_data(){
  344. $this->imagedata[$this->index]["disposal_method"] = $this->get_imagedata_bit("ext",3,3,3);
  345. $this->imagedata[$this->index]["user_input_flag"] = $this->get_imagedata_bit("ext",3,6,1);
  346. $this->imagedata[$this->index]["transparent_color_flag"] = $this->get_imagedata_bit("ext",3,7,1);
  347. $this->imagedata[$this->index]["delay_time"] = $this->dualbyteval($this->get_imagedata_byte("ext",4,2));
  348. $this->imagedata[$this->index]["transparent_color_index"] = ord($this->get_imagedata_byte("ext",6,1));
  349. $this->imagedata[$this->index]["offset_left"] = $this->dualbyteval($this->get_imagedata_byte("dat",1,2));
  350. $this->imagedata[$this->index]["offset_top"] = $this->dualbyteval($this->get_imagedata_byte("dat",3,2));
  351. $this->imagedata[$this->index]["width"] = $this->dualbyteval($this->get_imagedata_byte("dat",5,2));
  352. $this->imagedata[$this->index]["height"] = $this->dualbyteval($this->get_imagedata_byte("dat",7,2));
  353. $this->imagedata[$this->index]["local_color_table_flag"] = $this->get_imagedata_bit("dat",9,0,1);
  354. $this->imagedata[$this->index]["interlace_flag"] = $this->get_imagedata_bit("dat",9,1,1);
  355. $this->imagedata[$this->index]["sort_flag"] = $this->get_imagedata_bit("dat",9,2,1);
  356. $this->imagedata[$this->index]["color_table_size"] = pow(2,$this->get_imagedata_bit("dat",9,5,3)+1)*3;
  357. $this->imagedata[$this->index]["color_table"] = substr($this->imagedata[$this->index]["imagedata"],10,$this->imagedata[$this->index]["color_table_size"]);
  358. $this->imagedata[$this->index]["lzw_code_size"] = ord($this->get_imagedata_byte("dat",10,1));
  359. if($this->decoding){
  360. $this->orgvars[$this->index]["transparent_color_flag"] = $this->imagedata[$this->index]["transparent_color_flag"];
  361. $this->orgvars[$this->index]["transparent_color_index"] = $this->imagedata[$this->index]["transparent_color_index"];
  362. $this->orgvars[$this->index]["delay_time"] = $this->imagedata[$this->index]["delay_time"];
  363. $this->orgvars[$this->index]["disposal_method"] = $this->imagedata[$this->index]["disposal_method"];
  364. $this->orgvars[$this->index]["offset_left"] = $this->imagedata[$this->index]["offset_left"];
  365. $this->orgvars[$this->index]["offset_top"] = $this->imagedata[$this->index]["offset_top"];
  366. }
  367. }
  368. //-------------------------------------------------------
  369. private function get_imagedata_byte($type,$start,$length){
  370. if($type=="ext")
  371. return substr($this->imagedata[$this->index]["graphicsextension"],$start,$length);
  372. elseif($type=="dat")
  373. return substr($this->imagedata[$this->index]["imagedata"],$start,$length);
  374. }
  375. //-------------------------------------------------------
  376. private function get_imagedata_bit($type,$byteindex,$bitstart,$bitlength){
  377. if($type=="ext")
  378. return $this->readbits(ord(substr($this->imagedata[$this->index]["graphicsextension"],$byteindex,1)),$bitstart,$bitlength);
  379. elseif($type=="dat")
  380. return $this->readbits(ord(substr($this->imagedata[$this->index]["imagedata"],$byteindex,1)),$bitstart,$bitlength);
  381. }
  382. //-------------------------------------------------------
  383. private function dualbyteval($s){
  384. $i = ord($s[1])*256 + ord($s[0]);
  385. return $i;
  386. }
  387. //------------ Helper Functions ---------------------
  388. private function read_data_stream($first_length){
  389. $this->p_forward($first_length);
  390. $length=$this->readbyte_int();
  391. if($length!=0) {
  392. while($length!=0){
  393. $this->p_forward($length);
  394. $length=$this->readbyte_int();
  395. }
  396. }
  397. return true;
  398. }
  399. //-------------------------------------------------------
  400. private function loadfile($filename){
  401. $this->handle = fopen($filename,"rb");
  402. $this->pointer = 0;
  403. }
  404. //-------------------------------------------------------
  405. private function closefile(){
  406. fclose($this->handle);
  407. $this->handle=0;
  408. }
  409. //-------------------------------------------------------
  410. private function readbyte($byte_count){
  411. $data = fread($this->handle,$byte_count);
  412. $this->pointer += $byte_count;
  413. return $data;
  414. }
  415. //-------------------------------------------------------
  416. private function readbyte_int(){
  417. $data = fread($this->handle,1);
  418. $this->pointer++;
  419. return ord($data);
  420. }
  421. //-------------------------------------------------------
  422. private function readbits($byte,$start,$length){
  423. $bin = str_pad(decbin($byte),8,"0",STR_PAD_LEFT);
  424. $data = substr($bin,$start,$length);
  425. return bindec($data);
  426. }
  427. //-------------------------------------------------------
  428. private function p_rewind($length){
  429. $this->pointer-=$length;
  430. fseek($this->handle,$this->pointer);
  431. }
  432. //-------------------------------------------------------
  433. private function p_forward($length){
  434. $this->pointer+=$length;
  435. fseek($this->handle,$this->pointer);
  436. }
  437. //-------------------------------------------------------
  438. private function datapart($start,$length){
  439. fseek($this->handle,$start);
  440. $data = fread($this->handle,$length);
  441. fseek($this->handle,$this->pointer);
  442. return $data;
  443. }
  444. //-------------------------------------------------------
  445. private function checkbyte($byte){
  446. if(fgetc($this->handle)==chr($byte)){
  447. fseek($this->handle,$this->pointer);
  448. return true;
  449. }else{
  450. fseek($this->handle,$this->pointer);
  451. return false;
  452. }
  453. }
  454. //-------------------------------------------------------
  455. private function checkEOF(){
  456. if(fgetc($this->handle)===false){
  457. return true;
  458. }else{
  459. fseek($this->handle,$this->pointer);
  460. return false;
  461. }
  462. }
  463. //-------------------------------------------------------
  464. /**
  465. * Debug Functions.
  466. * Parses the GIF animation into single frames.
  467. */
  468. private function debug($string){
  469. echo "
    ";
  470. for($i=0;$i echo str_pad(dechex(ord($string[$i])),2,"0",STR_PAD_LEFT). " ";
  471. }
  472. echo "";
  473. }
  474. //-------------------------------------------------------
  475. private function debuglen($var,$len){
  476. echo "
    ";
  477. for($i=0;$i echo str_pad(dechex(ord($var[$i])),2,"0",STR_PAD_LEFT). " ";
  478. }
  479. echo "";
  480. }
  481. //-------------------------------------------------------
  482. private function debugstream($length){
  483. $this->debug($this->datapart($this->pointer,$length));
  484. }
  485. //-------------------------------------------------------
  486. /**
  487. * GD Resizer Device
  488. * Resizes the animation frames
  489. */
  490. private function resizeframes(){
  491. $k=0;
  492. foreach($this->parsedfiles as $img){
  493. $src = imagecreatefromgif($img);
  494. $sw = $this->imagedata[$k]["width"];
  495. $sh = $this->imagedata[$k]["height"];
  496. $nw = round($sw * $this->wr);
  497. $nh = round($sh * $this->hr);
  498. $sprite = imagecreatetruecolor($nw,$nh);
  499. $trans = imagecolortransparent($sprite);
  500. imagealphablending($sprite, false);
  501. imagesavealpha($sprite, true);
  502. imagepalettecopy($sprite,$src);
  503. imagefill($sprite,0,0,imagecolortransparent($src));
  504. imagecolortransparent($sprite,imagecolortransparent($src));
  505. imagecopyresized($sprite,$src,0,0,0,0,$nw,$nh,$sw,$sh);
  506. imagegif($sprite,$img);
  507. imagedestroy($sprite);
  508. imagedestroy($src);
  509. $k++;
  510. }
  511. }
  512. }
  515. ?>
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