I believe many people have thought about how to use PHP to generate GIF animation to implement dynamic image verification codes. The following is the implementation process.
The PHP source code of the GIF animation implemented by the ImageCode function through the GIFEncoder class. Interested friends can study it.
The effect is as shown below: 
Copy code The code is as follows:
/**
* ImageCode generates GIF image verification
* @param $string string
* @param $width width
* @param $height height
**/
function ImageCode($string = '', $width = 75, $height = 25)
{
$authstr = $string ? $string : ((time() % 2 == 0) ? mt_rand(1000, 9999) : mt_rand(10000, 99999));
$board_width = $width;
$board_height = $height;
// Generate a 32-frame GIF animation
for($i = 0; $i < 32; $i++)
{
ob_start();
$image = imagecreate($board_width, $board_height);
imagecolorallocate($image, 0,0,0);
//Set text color array
$colorList[] = ImageColorAllocate($image, 15,73,210);
$colorList[] = ImageColorAllocate($image, 0,64,0);
$colorList[] = ImageColorAllocate($image, 0,0,64);
$colorList[] = ImageColorAllocate($image, 0,128,128);
$colorList[] = ImageColorAllocate($image, 27,52,47);
$colorList[] = ImageColorAllocate($image, 51,0,102);
$colorList[] = ImageColorAllocate($image, 0,0,145);
$colorList[] = ImageColorAllocate($image, 0,0,113);
$colorList[] = ImageColorAllocate($image, 0,51,51);
$colorList[] = ImageColorAllocate($image, 158,180,35);
$colorList[] = ImageColorAllocate($image, 59,59,59);
$colorList[] = ImageColorAllocate($image, 0,0,0);
$colorList[] = ImageColorAllocate($image, 1,128,180);
$colorList[] = ImageColorAllocate($image, 0,153,51);
$colorList[] = ImageColorAllocate($image, 60,131,1);
$colorList[] = ImageColorAllocate($image, 0,0,0);
$fontcolor = ImageColorAllocate($image, 0,0,0);
$gray = ImageColorAllocate($image, 245,245,245);
$color = imagecolorallocate($image, 255,255,255);
$color2 = imagecolorallocate($image, 255,0,0);
imagefill($image, 0, 0, $gray);
$space = 15; // Character spacing
if($i > 0) // Mask the first frame
{
for ($k = 0; $k < strlen($authstr); $k++)
{
$colorRandom = mt_rand(0,sizeof($colorList)-1);
$float_top = rand(0,4);
$float_left = rand(0,3);
imagestring($image, 6, $space * $k, $top + $float_top, substr($authstr, $k, 1), $colorList[$colorRandom]);
}
}
for ($k = 0; $k < 20; $k++)
{
$colorRandom = mt_rand(0,sizeof($colorList)-1);
imagesetpixel($image, rand()%70 , rand()%15 , $colorList[$colorRandom]);
}
//Add interference line
for($k = 0; $k < 3; $k++)
{
$colorRandom = mt_rand(0, sizeof($colorList)-1);
// $todrawline = rand(0,1);
$todrawline = 1;
if($todrawline)
{
imageline($image, mt_rand(0, $board_width), mt_rand(0,$board_height), mt_rand(0,$board_width), mt_rand(0,$board_height), $colorList[$colorRandom]);
}
else
{
$w = mt_rand(0,$board_width);
$h = mt_rand(0,$board_width);
imagearc($image, $board_width - floor($w / 2) , floor($h / 2), $w, $h, rand(90,180), rand(180,270), $colorList[$colorRandom]);
}
}
imagegif($image);
imagedestroy($image);
$imagedata[] = ob_get_contents();
ob_clean();
++$i;
}
$gif = new GIFEncoder($imagedata);
Header ('Content-type:image/gif');
echo $gif->GetAnimation();
}
GIFEncoder class source code:
Copy code The code is as follows:
Class GIFEncoder {
var $GIF = "GIF89a"; /* GIF header 6 bytes */
var $VER = "GIFEncoder V2.06"; /* 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' =>"Could not make animation from animated GIF source",
);
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFEncoder...
::
*/
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 ( );
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFAddHeader...
::
*/
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";
}
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFAddFrames...
::
*/
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 >> 0 ) & 0xFF &
ord ( $Locals_rgb { 3 * $j + 1 } ) == ( $this->COL >> 8 ) & 0xFF &
ord ( $Locals_rgb { 3 * $j + 2 } ) == ( $this->COL >> 16 ) & 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;
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFAddFooter...
::
*/
function GIFAddFooter ( ) {
$this->GIF .= ";";
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFBlockCompare...
::
*/
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 );
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GIFWord...
::
*/
function GIFWord ( $int ) {
return ( chr ( $int & 0xFF ) . chr ( ( $int >> 8 ) & 0xFF ) );
}
/*
:::::::::::::::::::::::::::::::::::::::::::::::::::
::
:: GetAnimation...
::
*/
function GetAnimation ( ) {
return ( $this->GIF );
}
}
?>
http://www.bkjia.com/PHPjc/824715.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/824715.htmlTechArticleI believe many people have thought about how to use PHP to generate GIF animations to implement dynamic image verification codes. The following is the implementation process. The PHP source code of GIF animation implemented by the ImageCode function through the GIFEncoder class, there are...
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