php怎么调整gif动画图片尺寸

这篇文章主要介绍“php怎么调整gif动画图片尺寸”，在日常操作中，相信很多人在php怎么调整gif动画图片尺寸问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”php怎么调整gif动画图片尺寸”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

类的使用demo：

复制代码 代码如下:

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

类的源代码,保存为roucheng.php文件：

复制代码 代码如下:

<? /** * * Resizes Animated GIF Files * * ///IMPORTANT NOTE: The script needs a temporary directory where all the frames should be extracted. * Create a directory with a 777 permission level and write the path into $temp_dir variable below. * * Default directory is "frames". */ class gifresizer { public $temp_dir = "frames"; private $pointer = 0; private $index = 0; private $globaldata = array(); private $imagedata = array(); private $imageinfo = array(); private $handle = 0; private $orgvars = array(); private $encdata = array(); private $parsedfiles = array(); private $originalwidth = 0; private $originalheight = 0; private $wr,$hr; private $props = array(); private $decoding = false; /** * Public part of the class * * @orgfile - Original file path * @newfile - New filename with path * @width - Desired image width * @height - Desired image height */ function resize($orgfile,$newfile,$width,$height){ $this->decode($orgfile); $this->wr=$width/$this->originalwidth; $this->hr=$height/$this->originalheight; $this->resizeframes(); $this->encode($newfile,$width,$height); $this->clearframes(); } /** * GIF Decoder function. * Parses the GIF animation into single frames. */ private function decode($filename){ $this->decoding = true; $this->clearvariables(); $this->loadfile($filename); $this->get_gif_header(); $this->get_graphics_extension(0); $this->get_application_data(); $this->get_application_data(); $this->get_image_block(0); $this->get_graphics_extension(1); $this->get_comment_data(); $this->get_application_data(); $this->get_image_block(1); while(!$this->checkbyte(0x3b) && !$this->checkEOF()){ $this->get_comment_data(1); $this->get_graphics_extension(2); $this->get_image_block(2); } $this->writeframes(time()); $this->closefile(); $this->decoding = false; } /** * GIF Encoder function. * Combines the parsed GIF frames into one single animation. */ private function encode($new_filename,$newwidth,$newheight){ $mystring = ""; $this->pointer = 0; $this->imagedata = array(); $this->imageinfo = array(); $this->handle = 0; $this->index=0; $k=0; foreach($this->parsedfiles as $imagepart){ $this->loadfile($imagepart); $this->get_gif_header(); $this->get_application_data(); $this->get_comment_data(); $this->get_graphics_extension(0); $this->get_image_block(0); //get transparent color index and color if(isset($this->encdata[$this->index-1])) $gxdata = $this->encdata[$this->index-1]["graphicsextension"]; else $gxdata = null; $ghdata = $this->imageinfo["gifheader"]; $trcolor = ""; $hastransparency=($gxdata[3]&&1==1); if($hastransparency){ $trcx = ord($gxdata[6]); $trcolor = substr($ghdata,13+$trcx*3,3); } //global color table to image data; $this->transfercolortable($this->imageinfo["gifheader"],$this->imagedata[$this->index-1]["imagedata"]); $imageblock = &$this->imagedata[$this->index-1]["imagedata"]; //if transparency exists transfer transparency index if($hastransparency){ $haslocalcolortable = ((ord($imageblock[9])&128)==128); if($haslocalcolortable){ //local table exists. determine boundaries and look for it. $tablesize=(pow(2,(ord($imageblock[9])&7)+1)*3)+10; $this->orgvars[$this->index-1]["transparent_color_index"] = ((strrpos(substr($this->imagedata[$this->index-1]["imagedata"],0,$tablesize),$trcolor)-10)/3); }else{ //local table doesnt exist, look at the global one. $tablesize=(pow(2,(ord($gxdata[10])&7)+1)*3)+10; $this->orgvars[$this->index-1]["transparent_color_index"] = ((strrpos(substr($ghdata,0,$tablesize),$trcolor)-10)/3); } } //apply original delay time,transparent index and disposal values to graphics extension if(!$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); $imagedata = &$this->imagedata[$this->index-1]["graphicsextension"]; $imagedata[3] = chr((ord($imagedata[3]) & 0xE3) | ($this->orgvars[$this->index-1]["disposal_method"] << 2)); $imagedata[4] = chr(($this->orgvars[$this->index-1]["delay_time"] % 256)); $imagedata[5] = chr(floor($this->orgvars[$this->index-1]["delay_time"] / 256)); if($hastransparency){ $imagedata[6] = chr($this->orgvars[$this->index-1]["transparent_color_index"]); } $imagedata[3] = chr(ord($imagedata[3])|$hastransparency); //apply calculated left and top offset $imageblock[1] = chr(round(($this->orgvars[$this->index-1]["offset_left"]*$this->wr) % 256)); $imageblock[2] = chr(floor(($this->orgvars[$this->index-1]["offset_left"]*$this->wr) / 256)); $imageblock[3] = chr(round(($this->orgvars[$this->index-1]["offset_top"]*$this->hr) % 256)); $imageblock[4] = chr(floor(($this->orgvars[$this->index-1]["offset_top"]*$this->hr) / 256)); if($this->index==1){ if(!isset($this->imageinfo["applicationdata"]) || !$this->imageinfo["applicationdata"]) $this->imageinfo["applicationdata"]=chr(0x21).chr(0xff).chr(0x0b)."NETSCAPE2.0".chr(0x03).chr(0x01).chr(0x00).chr(0x00).chr(0x00); if(!isset($this->imageinfo["commentdata"]) || !$this->imageinfo["commentdata"]) $this->imageinfo["commentdata"] = chr(0x21).chr(0xfe).chr(0x10)."PHPGIFRESIZER1.0".chr(0); $mystring .= $this->orgvars["gifheader"]. $this->imageinfo["applicationdata"].$this->imageinfo["commentdata"]; if(isset($this->orgvars["hasgx_type_0"]) && $this->orgvars["hasgx_type_0"]) $mystring .= $this->globaldata["graphicsextension_0"]; if(isset($this->orgvars["hasgx_type_1"]) && $this->orgvars["hasgx_type_1"]) $mystring .= $this->globaldata["graphicsextension"]; } $mystring .= $imagedata . $imageblock; $k++; $this->closefile(); } $mystring .= chr(0x3b); //applying new width & height to gif header $mystring[6] = chr($newwidth % 256); $mystring[7] = chr(floor($newwidth / 256)); $mystring[8] = chr($newheight % 256); $mystring[9] = chr(floor($newheight / 256)); $mystring[11]= $this->orgvars["background_color"]; //if(file_exists($new_filename)){unlink($new_filename);} file_put_contents($new_filename,$mystring); } /** * Variable Reset function * If a instance is used multiple times, it's needed. Trust me. */ private function clearvariables(){ $this->pointer = 0; $this->index = 0; $this->imagedata = array(); $this->imageinfo = array(); $this->handle = 0; $this->parsedfiles = array(); } /** * Clear Frames function * For deleting the frames after encoding. */ private function clearframes(){ foreach($this->parsedfiles as $temp_frame){ unlink($temp_frame); } } /** * Frame Writer * Writes the GIF frames into files. */ private function writeframes($prepend){ for($i=0;$i<sizeof($this->imagedata);$i++){ file_put_contents($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)); $this->parsedfiles[]=$this->temp_dir."/frame_".$prepend."_".str_pad($i,2,"0",STR_PAD_LEFT).".gif"; } } /** * Color Palette Transfer Device * Transferring Global Color Table (GCT) from frames into Local Color Tables in animation. */ private function transfercolortable($src,&$dst){ //src is gif header,dst is image data block //if global color table exists,transfer it if((ord($src[10])&128)==128){ //Gif Header Global Color Table Length $ghctl = pow(2,$this->readbits(ord($src[10]),5,3)+1)*3; //cut global color table from gif header $ghgct = substr($src,13,$ghctl); //check image block color table length if((ord($dst[9])&128)==128){ //Image data contains color table. skip. }else{ //Image data needs a color table. //get last color table length so we can truncate the dummy color table $idctl = pow(2,$this->readbits(ord($dst[9]),5,3)+1)*3; //set color table flag and length $dst[9] = chr(ord($dst[9]) | (0x80 | (log($ghctl/3,2)-1))); //inject color table $dst = substr($dst,0,10).$ghgct.substr($dst,-1*strlen($dst)+10); } }else{ //global color table doesn't exist. skip. } } /** * GIF Parser Functions. * Below functions are the main structure parser components. */ private function get_gif_header(){ $this->p_forward(10); if($this->readbits(($mybyte=$this->readbyte_int()),0,1)==1){ $this->p_forward(2); $this->p_forward(pow(2,$this->readbits($mybyte,5,3)+1)*3); }else{ $this->p_forward(2); } $this->imageinfo["gifheader"]=$this->datapart(0,$this->pointer); if($this->decoding){ $this->orgvars["gifheader"]=$this->imageinfo["gifheader"]; $this->originalwidth = ord($this->orgvars["gifheader"][7])*256+ord($this->orgvars["gifheader"][6]); $this->originalheight = ord($this->orgvars["gifheader"][9])*256+ord($this->orgvars["gifheader"][8]); $this->orgvars["background_color"]=$this->orgvars["gifheader"][11]; } } //------------------------------------------------------- private function get_application_data(){ $startdata = $this->readbyte(2); if($startdata==chr(0x21).chr(0xff)){ $start = $this->pointer - 2; $this->p_forward($this->readbyte_int()); $this->read_data_stream($this->readbyte_int()); $this->imageinfo["applicationdata"] = $this->datapart($start,$this->pointer-$start); }else{ $this->p_rewind(2); } } //------------------------------------------------------- private function get_comment_data(){ $startdata = $this->readbyte(2); if($startdata==chr(0x21).chr(0xfe)){ $start = $this->pointer - 2; $this->read_data_stream($this->readbyte_int()); $this->imageinfo["commentdata"] = $this->datapart($start,$this->pointer-$start); }else{ $this->p_rewind(2); } } //------------------------------------------------------- private function get_graphics_extension($type){ $startdata = $this->readbyte(2); if($startdata==chr(0x21).chr(0xf9)){ $start = $this->pointer - 2; $this->p_forward($this->readbyte_int()); $this->p_forward(1); if($type==2){ $this->imagedata[$this->index]["graphicsextension"] = $this->datapart($start,$this->pointer-$start); }else if($type==1){ $this->orgvars["hasgx_type_1"] = 1; $this->globaldata["graphicsextension"] = $this->datapart($start,$this->pointer-$start); }else if($type==0 && $this->decoding==false){ $this->encdata[$this->index]["graphicsextension"] = $this->datapart($start,$this->pointer-$start); }else if($type==0 && $this->decoding==true){ $this->orgvars["hasgx_type_0"] = 1; $this->globaldata["graphicsextension_0"] = $this->datapart($start,$this->pointer-$start); } }else{ $this->p_rewind(2); } } //------------------------------------------------------- private function get_image_block($type){ if($this->checkbyte(0x2c)){ $start = $this->pointer; $this->p_forward(9); if($this->readbits(($mybyte=$this->readbyte_int()),0,1)==1){ $this->p_forward(pow(2,$this->readbits($mybyte,5,3)+1)*3); } $this->p_forward(1); $this->read_data_stream($this->readbyte_int()); $this->imagedata[$this->index]["imagedata"] = $this->datapart($start,$this->pointer-$start); if($type==0){ $this->orgvars["hasgx_type_0"] = 0; if(isset($this->globaldata["graphicsextension_0"])) $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension_0"]; else $this->imagedata[$this->index]["graphicsextension"]=null; unset($this->globaldata["graphicsextension_0"]); }elseif($type==1){ if(isset($this->orgvars["hasgx_type_1"]) && $this->orgvars["hasgx_type_1"]==1){ $this->orgvars["hasgx_type_1"] = 0; $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension"]; unset($this->globaldata["graphicsextension"]); }else{ $this->orgvars["hasgx_type_0"] = 0; $this->imagedata[$this->index]["graphicsextension"]=$this->globaldata["graphicsextension_0"]; unset($this->globaldata["graphicsextension_0"]); } } $this->parse_image_data(); $this->index++; } } //------------------------------------------------------- private function parse_image_data(){ $this->imagedata[$this->index]["disposal_method"] = $this->get_imagedata_bit("ext",3,3,3); $this->imagedata[$this->index]["user_input_flag"] = $this->get_imagedata_bit("ext",3,6,1); $this->imagedata[$this->index]["transparent_color_flag"] = $this->get_imagedata_bit("ext",3,7,1); $this->imagedata[$this->index]["delay_time"] = $this->dualbyteval($this->get_imagedata_byte("ext",4,2)); $this->imagedata[$this->index]["transparent_color_index"] = ord($this->get_imagedata_byte("ext",6,1)); $this->imagedata[$this->index]["offset_left"] = $this->dualbyteval($this->get_imagedata_byte("dat",1,2)); $this->imagedata[$this->index]["offset_top"] = $this->dualbyteval($this->get_imagedata_byte("dat",3,2)); $this->imagedata[$this->index]["width"] = $this->dualbyteval($this->get_imagedata_byte("dat",5,2)); $this->imagedata[$this->index]["height"] = $this->dualbyteval($this->get_imagedata_byte("dat",7,2)); $this->imagedata[$this->index]["local_color_table_flag"] = $this->get_imagedata_bit("dat",9,0,1); $this->imagedata[$this->index]["interlace_flag"] = $this->get_imagedata_bit("dat",9,1,1); $this->imagedata[$this->index]["sort_flag"] = $this->get_imagedata_bit("dat",9,2,1); $this->imagedata[$this->index]["color_table_size"] = pow(2,$this->get_imagedata_bit("dat",9,5,3)+1)*3; $this->imagedata[$this->index]["color_table"] = substr($this->imagedata[$this->index]["imagedata"],10,$this->imagedata[$this->index]["color_table_size"]); $this->imagedata[$this->index]["lzw_code_size"] = ord($this->get_imagedata_byte("dat",10,1)); if($this->decoding){ $this->orgvars[$this->index]["transparent_color_flag"] = $this->imagedata[$this->index]["transparent_color_flag"]; $this->orgvars[$this->index]["transparent_color_index"] = $this->imagedata[$this->index]["transparent_color_index"]; $this->orgvars[$this->index]["delay_time"] = $this->imagedata[$this->index]["delay_time"]; $this->orgvars[$this->index]["disposal_method"] = $this->imagedata[$this->index]["disposal_method"]; $this->orgvars[$this->index]["offset_left"] = $this->imagedata[$this->index]["offset_left"]; $this->orgvars[$this->index]["offset_top"] = $this->imagedata[$this->index]["offset_top"]; } } //------------------------------------------------------- private function get_imagedata_byte($type,$start,$length){ if($type=="ext") return substr($this->imagedata[$this->index]["graphicsextension"],$start,$length); elseif($type=="dat") return substr($this->imagedata[$this->index]["imagedata"],$start,$length); } //------------------------------------------------------- private function get_imagedata_bit($type,$byteindex,$bitstart,$bitlength){ if($type=="ext") return $this->readbits(ord(substr($this->imagedata[$this->index]["graphicsextension"],$byteindex,1)),$bitstart,$bitlength); elseif($type=="dat") return $this->readbits(ord(substr($this->imagedata[$this->index]["imagedata"],$byteindex,1)),$bitstart,$bitlength); } //------------------------------------------------------- private function dualbyteval($s){ $i = ord($s[1])*256 + ord($s[0]); return $i; } //------------ Helper Functions --------------------- private function read_data_stream($first_length){ $this->p_forward($first_length); $length=$this->readbyte_int(); if($length!=0) { while($length!=0){ $this->p_forward($length); $length=$this->readbyte_int(); } } return true; } //------------------------------------------------------- private function loadfile($filename){ $this->handle = fopen($filename,"rb"); $this->pointer = 0; } //------------------------------------------------------- private function closefile(){ fclose($this->handle); $this->handle=0; } //------------------------------------------------------- private function readbyte($byte_count){ $data = fread($this->handle,$byte_count); $this->pointer += $byte_count; return $data; } //------------------------------------------------------- private function readbyte_int(){ $data = fread($this->handle,1); $this->pointer++; return ord($data); } //------------------------------------------------------- private function readbits($byte,$start,$length){ $bin = str_pad(decbin($byte),8,"0",STR_PAD_LEFT); $data = substr($bin,$start,$length); return bindec($data); } //------------------------------------------------------- private function p_rewind($length){ $this->pointer-=$length; fseek($this->handle,$this->pointer); } //------------------------------------------------------- private function p_forward($length){ $this->pointer+=$length; fseek($this->handle,$this->pointer); } //------------------------------------------------------- private function datapart($start,$length){ fseek($this->handle,$start); $data = fread($this->handle,$length); fseek($this->handle,$this->pointer); return $data; } //------------------------------------------------------- private function checkbyte($byte){ if(fgetc($this->handle)==chr($byte)){ fseek($this->handle,$this->pointer); return true; }else{ fseek($this->handle,$this->pointer); return false; } } //------------------------------------------------------- private function checkEOF(){ if(fgetc($this->handle)===false){ return true; }else{ fseek($this->handle,$this->pointer); return false; } } //------------------------------------------------------- /** * Debug Functions. keleyi.com * Parses the GIF animation into single frames. */ private function debug($string){ echo "<pre>"; for($i=0;$i<strlen($string);$i++){ echo str_pad(dechex(ord($string[$i])),2,"0",STR_PAD_LEFT). " "; } echo "</pre>"; } //------------------------------------------------------- private function debuglen($var,$len){ echo "<pre>"; for($i=0;$i<$len;$i++){ echo str_pad(dechex(ord($var[$i])),2,"0",STR_PAD_LEFT). " "; } echo "</pre>"; } //------------------------------------------------------- private function debugstream($length){ $this->debug($this->datapart($this->pointer,$length)); } //------------------------------------------------------- /** * GD Resizer Device * Resizes the animation frames */ private function resizeframes(){ $k=0; foreach($this->parsedfiles as $img){ $src = imagecreatefromgif($img); $sw = $this->imagedata[$k]["width"]; $sh = $this->imagedata[$k]["height"]; $nw = round($sw * $this->wr); $nh = round($sh * $this->hr); $sprite = imagecreatetruecolor($nw,$nh); $trans = imagecolortransparent($sprite); imagealphablending($sprite, false); imagesavealpha($sprite, true); imagepalettecopy($sprite,$src); imagefill($sprite,0,0,imagecolortransparent($src)); imagecolortransparent($sprite,imagecolortransparent($src)); imagecopyresized($sprite,$src,0,0,0,0,$nw,$nh,$sw,$sh); imagegif($sprite,$img); imagedestroy($sprite); imagedestroy($src); $k++; } } }?>

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