PHP使用GIFEncoder类生成gif动态滚动字幕

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今天在公司,经理让做一个滚动字幕。但是,不许生成gif图片。所以上网找了GIFEncoder这个类库。确实很好用,但是,应用过程中也出现了一些问题,现在写在这里,以供后来人参考,少走弯路。

文字滚动分为两种情况。第一种为水平滚动:

代码如下:
PHP require_once("GIFEncoder.class.PHP"); $count=0; //设置默认计数器 while(true){ $str = $_REQUEST['str'] ? $_REQUEST['str']:"暂无输入"; $length=strlen($str)*9; //计算行长度,这个计算的比较简单,就是每个字数*9个像素 $im=imagecreatefromgif("hudongbg.gif"); //根据图片创建图像 $white = ImageColorAllocate($im,255,255); //设置一个白色 $str = iconv("GB2312","UTF-8",$str); //特别注意的是转换编码,因为之后用到的imagettftext只能用utf-8编码 $now=220-$count*5; //当前运行的水平位置 imagettftext($im,13,$now,20,$white,"ziti.ttf",$str); //根据字体在图片上写文字,参数意思(图像源,文字大小,倾斜角度,水平位置,垂直位置,颜色,使用的字体文件,要写的内容 imagegif($im); imagedestroy($im); $imagedata[] = ob_get_contents(); //创建这一帧的图像数据 ob_clean(); $count++; if ($now+$length<0){ //如果最后一个文字移动到头,那么结束 break; } } $diy[]=0;//开始延迟时间 $gif = new GIFEncoder($imagedata,$diy,2,"bin"); ob_start(); Header ('Content-type:image/gif'); echo $gif->GetAnimation(); ?>
然后是垂直的:
代码如下:
$v){ if( !$v ) unset( $array_str[$k] ); } for ($i=0,$length=count($array_str);$i<$length;$i++){ for ($k=0;$k<20;$k++){ $im=imagecreatefromgif("hudongbg.gif"); //根据图片创建图像 $white = ImageColorAllocate($im,255); //设置一个白色 $test = iconv("GB2312",$array_str[$i]); //特别注意的是转换编码,因为之后用到的imagettftext只能用utf-8编码,注意,一定要用字符串接收,不能用数组,否则会乱码 $heigth=40-$k; //当前文字高度 imagettftext($im,$heigth,$test); //将文字写入图片 imagegif($im); $imagedata[] = ob_get_contents(); ob_clean(); } } /* 这里是设置每一张图片的延迟时间,到第20帧的时候,延迟2秒。这样才能出现文字走到顶,停顿一会的效果 */ $delay=array(); for ($i=1,$length=count($array_str)*20;$i<=$length;$i++){ if ($i%20==0){ $delay[$i-1]="200"; }else{ $delay[$i-1]="1"; } } $transparent=array(0); $gif = new GIFEncoder($imagedata,$delay,$transparent,"bin"); ob_start(); Header ('Content-type:image/gif'); echo $gif->GetAnimation(); ?>

GIFEncoder类源码:

代码如下:
301"> "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 ],6,7 ); $this->GIF .= substr ( $this->BUF [ 0 ],$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 ); } } ?>

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