可以调整gif动画图片尺寸的很实用的php类建议收藏

<?php 
//http://www.cnblogs.com/roucheng/
require_once "roucheng.php";  
$gr = new gifresizer; 
$gr->temp_dir = "keleyi"; 
$gr->resize("keleyi.gif","keleyi_resized.gif",500,500); 
?>

 1 <?  2 /**  3  *  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 */  11  12 class gifresizer {  13  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 $decoding = false;  29  30 /**  31  * Public part of the class  32  *  33  * @orgfile - Original file path  34  * @newfile - New filename with path  35  * @width - Desired image width  36  * @height - Desired image height  37 */  38 function resize($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 $this->clearframes();  45  }  46  47 /**  48  * GIF Decoder function.  49  * Parses the GIF animation into single frames.  50 */  51 private function decode($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 $this->decoding = false;  72  }  73  74 /**  75  * GIF Encoder function.  76  * Combines the parsed GIF frames into one single animation.  77 */  78 private function encode($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;  85  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 $this->get_image_block(0);  94  95 //get transparent color index and color  96 if(isset($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); 103 104 if($hastransparency){ 105 $trcx = ord($gxdata[6]); 106 $trcolor = substr($ghdata,13+$trcx*3,3); 107  } 108 109 //global color table to image data; 110 $this->transfercolortable($this->imageinfo["gifheader"],$this->imagedata[$this->index-1]["imagedata"]); 111 112 $imageblock = &$this->imagedata[$this->index-1]["imagedata"]; 113 114 //if transparency exists transfer transparency index 115 if($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),$trcolor)-10)/3); 127  } 128  } 129 130 //apply original delay time,transparent index and disposal values to graphics extension 131 132 if(!$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); 133 134 $imagedata = &$this->imagedata[$this->index-1]["graphicsextension"]; 135 136 $imagedata[3] = chr((ord($imagedata[3]) & 0xE3) | ($this->orgvars[$this->index-1]["disposal_method"] << 2)); 137 $imagedata[4] = chr(($this->orgvars[$this->index-1]["delay_time"] % 256)); 138 $imagedata[5] = chr(floor($this->orgvars[$this->index-1]["delay_time"] / 256)); 139 if($hastransparency){ 140 $imagedata[6] = chr($this->orgvars[$this->index-1]["transparent_color_index"]); 141  } 142 $imagedata[3] = chr(ord($imagedata[3])|$hastransparency); 143 144 //apply calculated left and top offset  145 $imageblock[1] = chr(round(($this->orgvars[$this->index-1]["offset_left"]*$this->wr) % 256)); 146 $imageblock[2] = chr(floor(($this->orgvars[$this->index-1]["offset_left"]*$this->wr) / 256)); 147 $imageblock[3] = chr(round(($this->orgvars[$this->index-1]["offset_top"]*$this->hr) % 256)); 148 $imageblock[4] = chr(floor(($this->orgvars[$this->index-1]["offset_top"]*$this->hr) / 256)); 149 150 if($this->index==1){ 151 if(!isset($this->imageinfo["applicationdata"]) || !$this->imageinfo["applicationdata"]) 152 $this->imageinfo["applicationdata"]=chr(0x21).chr(0xff).chr(0x0b)."NETSCAPE2.0".chr(0x03).chr(0x01).chr(0x00).chr(0x00).chr(0x00); 153 if(!isset($this->imageinfo["commentdata"]) || !$this->imageinfo["commentdata"]) 154 $this->imageinfo["commentdata"] = chr(0x21).chr(0xfe).chr(0x10)."PHPGIFRESIZER1.0".chr(0); 155 $mystring .= $this->orgvars["gifheader"]. $this->imageinfo["applicationdata"].$this->imageinfo["commentdata"]; 156 if(isset($this->orgvars["hasgx_type_0"]) && $this->orgvars["hasgx_type_0"]) $mystring .= $this->globaldata["graphicsextension_0"]; 157 if(isset($this->orgvars["hasgx_type_1"]) && $this->orgvars["hasgx_type_1"]) $mystring .= $this->globaldata["graphicsextension"]; 158  } 159 160 $mystring .= $imagedata . $imageblock; 161 $k++; 162 $this->closefile(); 163  } 164 165 $mystring .= chr(0x3b); 166 167 //applying new width & height to gif header 168 $mystring[6] = chr($newwidth % 256); 169 $mystring[7] = chr(floor($newwidth / 256)); 170 $mystring[8] = chr($newheight % 256); 171 $mystring[9] = chr(floor($newheight / 256)); 172 $mystring[11]= $this->orgvars["background_color"]; 173 //if(file_exists($new_filename)){unlink($new_filename);} 174 file_put_contents($new_filename,$mystring); 175  } 176 177 /** 178  * Variable Reset function 179  * If a instance is used multiple times, it's needed. Trust me. 180 */ 181 private function clearvariables(){ 182 $this->pointer = 0; 183 $this->index = 0; 184 $this->imagedata = array(); 185 $this->imageinfo = array(); 186 $this->handle = 0; 187 $this->parsedfiles = array(); 188  } 189 190 /** 191  * Clear Frames function 192  * For deleting the frames after encoding. 193 */ 194 private function clearframes(){ 195 foreach($this->parsedfiles as $temp_frame){ 196 unlink($temp_frame); 197  } 198  } 199 200 /** 201  * Frame Writer 202  * Writes the GIF frames into files. 203 */ 204 private function writeframes($prepend){ 205 for($i=0;$i<sizeof($this->imagedata);$i++){ 206 file_put_contents($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)); 207 $this->parsedfiles[]=$this->temp_dir."/frame_".$prepend."_".str_pad($i,2,"0",STR_PAD_LEFT).".gif"; 208  } 209  } 210 211 /** 212  * Color Palette Transfer Device 213  * Transferring Global Color Table (GCT) from frames into Local Color Tables in animation. 214 */ 215 private function transfercolortable($src,&$dst){ 216 //src is gif header,dst is image data block 217  //if global color table exists,transfer it 218 if((ord($src[10])&128)==128){ 219 //Gif Header Global Color Table Length 220 $ghctl = pow(2,$this->readbits(ord($src[10]),5,3)+1)*3; 221 //cut global color table from gif header 222 $ghgct = substr($src,13,$ghctl); 223 //check image block color table length 224 if((ord($dst[9])&128)==128){ 225 //Image data contains color table. skip. 226 }else{ 227 //Image data needs a color table. 228  //get last color table length so we can truncate the dummy color table 229 $idctl = pow(2,$this->readbits(ord($dst[9]),5,3)+1)*3; 230 //set color table flag and length  231 $dst[9] = chr(ord($dst[9]) | (0x80 | (log($ghctl/3,2)-1))); 232 //inject color table 233 $dst = substr($dst,0,10).$ghgct.substr($dst,-1*strlen($dst)+10); 234  } 235 }else{ 236 //global color table doesn't exist. skip. 237  } 238  } 239 240 /** 241  * GIF Parser Functions. 242  * Below functions are the main structure parser components. 243 */ 244 private function get_gif_header(){ 245 $this->p_forward(10); 246 if($this->readbits(($mybyte=$this->readbyte_int()),0,1)==1){ 247 $this->p_forward(2); 248 $this->p_forward(pow(2,$this->readbits($mybyte,5,3)+1)*3); 249 }else{ 250 $this->p_forward(2); 251  } 252 253 $this->imageinfo["gifheader"]=$this->datapart(0,$this->pointer); 254 if($this->decoding){ 255 $this->orgvars["gifheader"]=$this->imageinfo["gifheader"]; 256 $this->originalwidth = ord($this->orgvars["gifheader"][7])*256+ord($this->orgvars["gifheader"][6]); 257 $this->originalheight = ord($this->orgvars["gifheader"][9])*256+ord($this->orgvars["gifheader"][8]); 258 $this->orgvars["background_color"]=$this->orgvars["gifheader"][11]; 259  } 260 261  } 262 //------------------------------------------------------- 263 private function get_application_data(){ 264 $startdata = $this->readbyte(2); 265 if($startdata==chr(0x21).chr(0xff)){ 266 $start = $this->pointer - 2; 267 $this->p_forward($this->readbyte_int()); 268 $this->read_data_stream($this->readbyte_int()); 269 $this->imageinfo["applicationdata"] = $this->datapart($start,$this->pointer-$start); 270 }else{ 271 $this->p_rewind(2); 272  } 273  } 274 //------------------------------------------------------- 275 private function get_comment_data(){ 276 $startdata = $this->readbyte(2); 277 if($startdata==chr(0x21).chr(0xfe)){ 278 $start = $this->pointer - 2; 279 $this->read_data_stream($this->readbyte_int()); 280 $this->imageinfo["commentdata"] = $this->datapart($start,$this->pointer-$start); 281 }else{ 282 $this->p_rewind(2); 283  } 284  } 285 //------------------------------------------------------- 286 private function get_graphics_extension($type){ 287 $startdata = $this->readbyte(2); 288 if($startdata==chr(0x21).chr(0xf9)){ 289 $start = $this->pointer - 2; 290 $this->p_forward($this->readbyte_int()); 291 $this->p_forward(1); 292 if($type==2){ 293 $this->imagedata[$this->index]["graphicsextension"] = $this->datapart($start,$this->pointer-$start); 294 }else if($type==1){ 295 $this->orgvars["hasgx_type_1"] = 1; 296 $this->globaldata["graphicsextension"] = $this->datapart($start,$this->pointer-$start); 297 }else if($type==0 && $this->decoding==false){ 298 $this->encdata[$this->index]["graphicsextension"] = $this->datapart($start,$this->pointer-$start); 299 }else if($type==0 && $this->decoding==true){ 300 $this->orgvars["hasgx_type_0"] = 1; 301 $this->globaldata["graphicsextension_0"] = $this->datapart($start,$this->pointer-$start); 302  } 303 }else{ 304 $this->p_rewind(2); 305  } 306  } 307 //------------------------------------------------------- 308 private function get_image_block($type){ 309 if($this->checkbyte(0x2c)){ 310 $start = $this->pointer; 311 $this->p_forward(9); 312 if($this->readbits(($mybyte=$this->readbyte_int()),0,1)==1){ 313 $this->p_forward(pow(2,$this->readbits($mybyte,5,3)+1)*3); 314  } 315 $this->p_forward(1); 316 $this->read_data_stream($this->readbyte_int()); 317 $this->imagedata[$this->index]["imagedata"] = $this->datapart($start,$this->pointer-$start); 318 319 if($type==0){ 320 $this->orgvars["hasgx_type_0"] = 0; 321 if(isset($this->globaldata["graphicsextension_0"])) 322 $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension_0"]; 323 else 324 $this->imagedata[$this->index]["graphicsextension"]=null; 325 unset($this->globaldata["graphicsextension_0"]); 326 }elseif($type==1){ 327 if(isset($this->orgvars["hasgx_type_1"]) && $this->orgvars["hasgx_type_1"]==1){ 328 $this->orgvars["hasgx_type_1"] = 0; 329 $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension"]; 330 unset($this->globaldata["graphicsextension"]); 331 }else{ 332 $this->orgvars["hasgx_type_0"] = 0; 333 $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension_0"]; 334 unset($this->globaldata["graphicsextension_0"]); 335  } 336  } 337 338 $this->parse_image_data(); 339 $this->index++; 340 341  } 342  } 343 //------------------------------------------------------- 344 private function parse_image_data(){ 345 $this->imagedata[$this->index]["disposal_method"] = $this->get_imagedata_bit("ext",3,3,3); 346 $this->imagedata[$this->index]["user_input_flag"] = $this->get_imagedata_bit("ext",3,6,1); 347 $this->imagedata[$this->index]["transparent_color_flag"] = $this->get_imagedata_bit("ext",3,7,1); 348 $this->imagedata[$this->index]["delay_time"] = $this->dualbyteval($this->get_imagedata_byte("ext",4,2)); 349 $this->imagedata[$this->index]["transparent_color_index"] = ord($this->get_imagedata_byte("ext",6,1)); 350 $this->imagedata[$this->index]["offset_left"] = $this->dualbyteval($this->get_imagedata_byte("dat",1,2)); 351 $this->imagedata[$this->index]["offset_top"] = $this->dualbyteval($this->get_imagedata_byte("dat",3,2)); 352 $this->imagedata[$this->index]["width"] = $this->dualbyteval($this->get_imagedata_byte("dat",5,2)); 353 $this->imagedata[$this->index]["height"] = $this->dualbyteval($this->get_imagedata_byte("dat",7,2)); 354 $this->imagedata[$this->index]["local_color_table_flag"] = $this->get_imagedata_bit("dat",9,0,1); 355 $this->imagedata[$this->index]["interlace_flag"] = $this->get_imagedata_bit("dat",9,1,1); 356 $this->imagedata[$this->index]["sort_flag"] = $this->get_imagedata_bit("dat",9,2,1); 357 $this->imagedata[$this->index]["color_table_size"] = pow(2,$this->get_imagedata_bit("dat",9,5,3)+1)*3; 358 $this->imagedata[$this->index]["color_table"] = substr($this->imagedata[$this->index]["imagedata"],10,$this->imagedata[$this->index]["color_table_size"]); 359 $this->imagedata[$this->index]["lzw_code_size"] = ord($this->get_imagedata_byte("dat",10,1)); 360 if($this->decoding){ 361 $this->orgvars[$this->index]["transparent_color_flag"] = $this->imagedata[$this->index]["transparent_color_flag"]; 362 $this->orgvars[$this->index]["transparent_color_index"] = $this->imagedata[$this->index]["transparent_color_index"]; 363 $this->orgvars[$this->index]["delay_time"] = $this->imagedata[$this->index]["delay_time"]; 364 $this->orgvars[$this->index]["disposal_method"] = $this->imagedata[$this->index]["disposal_method"]; 365 $this->orgvars[$this->index]["offset_left"] = $this->imagedata[$this->index]["offset_left"]; 366 $this->orgvars[$this->index]["offset_top"] = $this->imagedata[$this->index]["offset_top"]; 367  } 368  } 369 //------------------------------------------------------- 370 private function get_imagedata_byte($type,$start,$length){ 371 if($type=="ext") 372 return substr($this->imagedata[$this->index]["graphicsextension"],$start,$length); 373 elseif($type=="dat") 374 return substr($this->imagedata[$this->index]["imagedata"],$start,$length); 375  } 376 //------------------------------------------------------- 377 private function get_imagedata_bit($type,$byteindex,$bitstart,$bitlength){ 378 if($type=="ext") 379 return $this->readbits(ord(substr($this->imagedata[$this->index]["graphicsextension"],$byteindex,1)),$bitstart,$bitlength); 380 elseif($type=="dat") 381 return $this->readbits(ord(substr($this->imagedata[$this->index]["imagedata"],$byteindex,1)),$bitstart,$bitlength); 382  } 383 //------------------------------------------------------- 384 private function dualbyteval($s){ 385 $i = ord($s[1])*256 + ord($s[0]); 386 return $i; 387  } 388 //------------ Helper Functions --------------------- 389 private function read_data_stream($first_length){ 390 $this->p_forward($first_length); 391 $length=$this->readbyte_int(); 392 if($length!=0) { 393 while($length!=0){ 394 $this->p_forward($length); 395 $length=$this->readbyte_int(); 396  } 397  } 398 return true; 399  } 400 //------------------------------------------------------- 401 private function loadfile($filename){ 402 $this->handle = fopen($filename,"rb"); 403 $this->pointer = 0; 404  } 405 //------------------------------------------------------- 406 private function closefile(){ 407 fclose($this->handle); 408 $this->handle=0; 409  } 410 //------------------------------------------------------- 411 private function readbyte($byte_count){ 412 $data = fread($this->handle,$byte_count); 413 $this->pointer += $byte_count; 414 return $data; 415  } 416 //------------------------------------------------------- 417 private function readbyte_int(){ 418 $data = fread($this->handle,1); 419 $this->pointer++; 420 return ord($data); 421  } 422 //------------------------------------------------------- 423 private function readbits($byte,$start,$length){ 424 $bin = str_pad(decbin($byte),8,"0",STR_PAD_LEFT); 425 $data = substr($bin,$start,$length); 426 return bindec($data); 427  } 428 //------------------------------------------------------- 429 private function p_rewind($length){ 430 $this->pointer-=$length; 431 fseek($this->handle,$this->pointer); 432  } 433 //------------------------------------------------------- 434 private function p_forward($length){ 435 $this->pointer+=$length; 436 fseek($this->handle,$this->pointer); 437  } 438 //------------------------------------------------------- 439 private function datapart($start,$length){ 440 fseek($this->handle,$start); 441 $data = fread($this->handle,$length); 442 fseek($this->handle,$this->pointer); 443 return $data; 444  } 445 //------------------------------------------------------- 446 private function checkbyte($byte){ 447 if(fgetc($this->handle)==chr($byte)){ 448 fseek($this->handle,$this->pointer); 449 return true; 450 }else{ 451 fseek($this->handle,$this->pointer); 452 return false; 453  } 454  } 455 //------------------------------------------------------- 456 private function checkEOF(){ 457 if(fgetc($this->handle)===false){ 458 return true; 459 }else{ 460 fseek($this->handle,$this->pointer); 461 return false; 462  } 463  } 464 //------------------------------------------------------- 465 /** 466  * Debug Functions. keleyi.com 467  * Parses the GIF animation into single frames. 468 */ 469 private function debug($string){ 470 echo "<pre>"; 471 for($i=0;$i<strlen($string);$i++){ 472 echo str_pad(dechex(ord($string[$i])),2,"0",STR_PAD_LEFT). " "; 473  } 474 echo "</pre>"; 475  } 476 //------------------------------------------------------- 477 private function debuglen($var,$len){ 478 echo "<pre>"; 479 for($i=0;$i<$len;$i++){ 480 echo str_pad(dechex(ord($var[$i])),2,"0",STR_PAD_LEFT). " "; 481  } 482 echo "</pre>"; 483  } 484 //------------------------------------------------------- 485 private function debugstream($length){ 486 $this->debug($this->datapart($this->pointer,$length)); 487  } 488 //------------------------------------------------------- 489 /** 490  * GD Resizer Device 491  * Resizes the animation frames 492 */ 493 private function resizeframes(){ 494 $k=0; 495 foreach($this->parsedfiles as $img){ 496 $src = imagecreatefromgif($img); 497 $sw = $this->imagedata[$k]["width"]; 498 $sh = $this->imagedata[$k]["height"]; 499 $nw = round($sw * $this->wr); 500 $nh = round($sh * $this->hr); 501 $sprite = imagecreatetruecolor($nw,$nh); 502 $trans = imagecolortransparent($sprite); 503 imagealphablending($sprite, false); 504 imagesavealpha($sprite, true); 505 imagepalettecopy($sprite,$src); 506 imagefill($sprite,0,0,imagecolortransparent($src)); 507 imagecolortransparent($sprite,imagecolortransparent($src)); 508 imagecopyresized($sprite,$src,0,0,0,0,$nw,$nh,$sw,$sh); 509 imagegif($sprite,$img); 510 imagedestroy($sprite); 511 imagedestroy($src); 512 $k++; 513  } 514  } 515  } 516 517 518 ?>