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:
/** * 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, 0,0,0); // 设定文字颜色数组 $colorList[] = ImageColorAllocate($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); $space = 15; // 字符间距 if($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, $board_width), mt_rand(0,$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类源码:
<?php 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 ); } } ?>