PHP使用GIFEncoder类生成的GIF动态图片验证码

相信很多人都想过如何用PHP生成GIF动画来实现动态图片验证码，以下是实现过程。 ImageCode函数通过GIFEncoder类实现的GIF动画的PHP源代码，有兴趣的朋友可以研究一下。

效果如图：

代码如下:

ImageCode 生成gif图片验证

@param $string 字符串

@param $width 宽度

@param $height 高度

*/

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;

// 生成一个32帧的GIF动画

for($i = 0; $i < 32; $i++)

{

ob_start();

$image = imagecreate($board_width,$board_height);

imagecolorallocate($image,0);

// 设定文字颜色数组

$colorList[] = ImageColorAllocate($image,15,73,210);

$colorList[] = ImageColorAllocate($image,64,0);

$colorList[] = ImageColorAllocate($image,64);

$colorList[] = ImageColorAllocate($image,128,128);

$colorList[] = ImageColorAllocate($image,27,52,47);

$colorList[] = ImageColorAllocate($image,51,102);

$colorList[] = ImageColorAllocate($image,145);

$colorList[] = ImageColorAllocate($image,113);

$colorList[] = ImageColorAllocate($image,51);

$colorList[] = ImageColorAllocate($image,158,180,35);

$colorList[] = ImageColorAllocate($image,59,59);

$colorList[] = ImageColorAllocate($image,1,180);

$colorList[] = ImageColorAllocate($image,153,60,131,1);

$colorList[] = ImageColorAllocate($image,0);

$fontcolor = ImageColorAllocate($image,0);

$gray = ImageColorAllocate($image,245,245);

$color = imagecolorallocate($image,255,255);

$color2 = imagecolorallocate($image,0);

imagefill($image,$gray);

$space = 15; // 字符间距

if($i > 0) // 屏蔽第一帧

{

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]);

}

// 添加干扰线

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),$board_height),$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类源码：

代码如下:

"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->ERR [ 'ERR02' ],$GIF_mod ); exit ( 0 ); } if ( substr ( $this->BUF [ $i ],6 ) != "GIF87a" && substr ( $this->BUF [ $i ],6 ) != "GIF89a" ) { printf ( "%s: %d %s",$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->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 ],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 ], 3 * ( 2 << ( ord ( $this->BUF [ 0 ] { 10 } ) & 0x07 ) ) ); $Locals_rgb = substr ( $this->BUF [ $i ], 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,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 ); } } ?>