Animated GIF with PHP

Hi,

This is another intersting topic. If you want to make a frame based animated GIF file using PHP, then this post is exactly what you need. First of all you need to include() the class file in your .php file. The class is attached at the end of this post. The basic idea of creating a framed based animation is to create to arrays. the first array will contain the path of the frames, which basically are simple image file and the second array will define the duration one particular frame will have. e.g.

if ( $dh = opendir ( "frames/" ) ) {
 while ( false !== ( $dat = readdir ( $dh ) ) ) {
  if ( $dat != "." && $dat != ".." ) {
  $ext=substr($dat,-3,3);
   if(strtolower($ext)=="gif"){
    $frames [ ] = "frames/$dat";
    $framed [ ] = 5;
   }
  }
 }
 closedir ( $dh );
}

In the above code $frames[] holds the path of each image file which are in "frames/" directory, and $framed  has the duration of each frame respectively. You can customize the above code as per your need.

The main trick of creating the animated single GIF file is:
$gif = new GIFEncoder ($frames, $framed, 0, 2, 0, 0, 0, "url");
Header ( 'Content-type:image/gif' );
echo $gif->GetAnimation ( );

Thats it. The animated gif gets created and shows on the current webpage.

The content of the actual class file is:

<?php

Class GIFEncoder {
 var $GIF = "GIF89a";  /* GIF header 6 bytes */
 var $VER = "GIFEncoder V2.05"; /* Encoder version  */
 var $BUF = Array ( );
 var $LOP =  0;
 var $DIS =  2;
 var $COL = -1;
 var $IMG = -1;
 var $ERR = Array (
  ERR00=>"Does not supported function for only one image!",
  ERR01=>"Source is not a GIF image!",
  ERR02=>"Unintelligible flag ",
  ERR03=>"Does not make animation from animated GIF source",
 );
 function GIFEncoder (
       $GIF_src, $GIF_dly, $GIF_lop, $GIF_dis,
       $GIF_red, $GIF_grn, $GIF_blu, $GIF_mod
      ) {
  if ( ! is_array ( $GIF_src ) && ! is_array ( $GIF_tim ) ) {
   printf ( "%s: %s", $this->VER, $this->ERR [ 'ERR00' ] );
   exit ( 0 );
  }
  $this->LOP = ( $GIF_lop > -1 ) ? $GIF_lop : 0;
  $this->DIS = ( $GIF_dis > -1 ) ? ( ( $GIF_dis < 3 ) ? $GIF_dis : 3 ) : 2;
  $this->COL = ( $GIF_red > -1 && $GIF_grn > -1 && $GIF_blu > -1 ) ?
      ( $GIF_red | ( $GIF_grn << 8 ) | ( $GIF_blu << 16 ) ) : -1;
  for ( $i = 0; $i < count ( $GIF_src ); $i++ ) {
   if ( strToLower ( $GIF_mod ) == "url" ) {
    $this->BUF [ ] = fread ( fopen ( $GIF_src [ $i ], "rb" ), filesize ( $GIF_src [ $i ] ) );
   }
   else if ( strToLower ( $GIF_mod ) == "bin" ) {
    $this->BUF [ ] = $GIF_src [ $i ];
   }
   else {
    printf ( "%s: %s ( %s )!", $this->VER, $this->ERR [ 'ERR02' ], $GIF_mod );
    exit ( 0 );
   }
   if ( substr ( $this->BUF [ $i ], 0, 6 ) != "GIF87a" && substr ( $this->BUF [ $i ], 0, 6 ) != "GIF89a" ) {
    printf ( "%s: %d %s", $this->VER, $i, $this->ERR [ 'ERR01' ] );
    exit ( 0 );
   }
   for ( $j = ( 13 + 3 * ( 2 << ( ord ( $this->BUF [ $i ] { 10 } ) & 0x07 ) ) ), $k = TRUE; $k; $j++ ) {
    switch ( $this->BUF [ $i ] { $j } ) {
     case "!":
      if ( ( substr ( $this->BUF [ $i ], ( $j + 3 ), 8 ) ) == "NETSCAPE" ) {
       printf ( "%s: %s ( %s source )!", $this->VER, $this->ERR [ 'ERR03' ], ( $i + 1 ) );
       exit ( 0 );
      }
      break;
     case ";":
      $k = FALSE;
      break;
    }
   }
  }
  GIFEncoder::GIFAddHeader ( );
  for ( $i = 0; $i < count ( $this->BUF ); $i++ ) {
   GIFEncoder::GIFAddFrames ( $i, $GIF_dly [ $i ] );
  }
  GIFEncoder::GIFAddFooter ( );
 }
 function GIFAddHeader ( ) {
  $cmap = 0;
  if ( ord ( $this->BUF [ 0 ] { 10 } ) & 0x80 ) {
   $cmap = 3 * ( 2 << ( ord ( $this->BUF [ 0 ] { 10 } ) & 0x07 ) );
   $this->GIF .= substr ( $this->BUF [ 0 ], 6, 7  );
   $this->GIF .= substr ( $this->BUF [ 0 ], 13, $cmap );
   $this->GIF .= "!\377\13NETSCAPE2.0\3\1" . GIFEncoder::GIFWord ( $this->LOP ) . "\0";
  }
 }
 function GIFAddFrames ( $i, $d ) {
  $Locals_str = 13 + 3 * ( 2 << ( ord ( $this->BUF [ $i ] { 10 } ) & 0x07 ) );
  $Locals_end = strlen ( $this->BUF [ $i ] ) - $Locals_str - 1;
  $Locals_tmp = substr ( $this->BUF [ $i ], $Locals_str, $Locals_end );
  $Global_len = 2 << ( ord ( $this->BUF [ 0  ] { 10 } ) & 0x07 );
  $Locals_len = 2 << ( ord ( $this->BUF [ $i ] { 10 } ) & 0x07 );
  $Global_rgb = substr ( $this->BUF [ 0  ], 13,
       3 * ( 2 << ( ord ( $this->BUF [ 0  ] { 10 } ) & 0x07 ) ) );
  $Locals_rgb = substr ( $this->BUF [ $i ], 13,
       3 * ( 2 << ( ord ( $this->BUF [ $i ] { 10 } ) & 0x07 ) ) );
  $Locals_ext = "!\xF9\x04" . chr ( ( $this->DIS << 2 ) + 0 ) .
      chr ( ( $d >> 0 ) & 0xFF ) . chr ( ( $d >> 8 ) & 0xFF ) . "\x0\x0";
  if ( $this->COL > -1 && ord ( $this->BUF [ $i ] { 10 } ) & 0x80 ) {
   for ( $j = 0; $j < ( 2 << ( ord ( $this->BUF [ $i ] { 10 } ) & 0x07 ) ); $j++ ) {
    if (
      ord ( $Locals_rgb { 3 * $j + 0 } ) == ( ( $this->COL >> 16 ) & 0xFF ) &&
      ord ( $Locals_rgb { 3 * $j + 1 } ) == ( ( $this->COL >>  8 ) & 0xFF ) &&
      ord ( $Locals_rgb { 3 * $j + 2 } ) == ( ( $this->COL >>  0 ) & 0xFF )
     ) {
     $Locals_ext = "!\xF9\x04" . chr ( ( $this->DIS << 2 ) + 1 ) .
         chr ( ( $d >> 0 ) & 0xFF ) . chr ( ( $d >> 8 ) & 0xFF ) . chr ( $j ) . "\x0";
     break;
    }
   }
  }
  switch ( $Locals_tmp { 0 } ) {
   case "!":
    $Locals_img = substr ( $Locals_tmp, 8, 10 );
    $Locals_tmp = substr ( $Locals_tmp, 18, strlen ( $Locals_tmp ) - 18 );
    break;
   case ",":
    $Locals_img = substr ( $Locals_tmp, 0, 10 );
    $Locals_tmp = substr ( $Locals_tmp, 10, strlen ( $Locals_tmp ) - 10 );
    break;
  }
  if ( ord ( $this->BUF [ $i ] { 10 } ) & 0x80 && $this->IMG > -1 ) {
   if ( $Global_len == $Locals_len ) {
    if ( GIFEncoder::GIFBlockCompare ( $Global_rgb, $Locals_rgb, $Global_len ) ) {
     $this->GIF .= ( $Locals_ext . $Locals_img . $Locals_tmp );
    }
    else {
     $byte  = ord ( $Locals_img { 9 } );
     $byte |= 0x80;
     $byte &= 0xF8;
     $byte |= ( ord ( $this->BUF [ 0 ] { 10 } ) & 0x07 );
     $Locals_img { 9 } = chr ( $byte );
     $this->GIF .= ( $Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp );
    }
   }
   else {
    $byte  = ord ( $Locals_img { 9 } );
    $byte |= 0x80;
    $byte &= 0xF8;
    $byte |= ( ord ( $this->BUF [ $i ] { 10 } ) & 0x07 );
    $Locals_img { 9 } = chr ( $byte );
    $this->GIF .= ( $Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp );
   }
  }
  else {
   $this->GIF .= ( $Locals_ext . $Locals_img . $Locals_tmp );
  }
  $this->IMG  = 1;
 }
 function GIFAddFooter ( ) {
  $this->GIF .= ";";
 }
 function GIFBlockCompare ( $GlobalBlock, $LocalBlock, $Len ) {
  for ( $i = 0; $i < $Len; $i++ ) {
   if (
     $GlobalBlock { 3 * $i + 0 } != $LocalBlock { 3 * $i + 0 } ||
     $GlobalBlock { 3 * $i + 1 } != $LocalBlock { 3 * $i + 1 } ||
     $GlobalBlock { 3 * $i + 2 } != $LocalBlock { 3 * $i + 2 }
    ) {
     return ( 0 );
   }
  }
  return ( 1 );
 }
 function GIFWord ( $int ) {
  return ( chr ( $int & 0xFF ) . chr ( ( $int >> 8 ) & 0xFF ) );
 }
 function GetAnimation ( ) {
  return ( $this->GIF );
 }
}
?>

Save it as animate_class.php and the second php, say animate.php, will have:

<?php
require("animate_class.php");

if ( $dh = opendir ( "frames/" ) ) {
 while ( false !== ( $dat = readdir ( $dh ) ) ) {
  if ( $dat != "." && $dat != ".." ) {
  $ext=substr($dat,-3,3);
   if(strtolower($ext)=="gif"){
    $frames [ ] = "frames/$dat";
    $framed [ ] = 5;
   }
  }
 }
 closedir ( $dh );

$gif = new GIFEncoder ($frames, $framed, 0, 2, 0, 0, 0, "url");
Header ( 'Content-type:image/gif' );
echo $gif->GetAnimation ( );

?>

Create a folder "frames" with a bunch of static GIF file and execute animate.php and see animated GIF.

For more details see:
PHP Classes

Best,