function generateImg($source, $text1, $text2, $text3, $font = './msyhbd.ttf') {
    $date = '' . date ( 'Ymd' ) . '/';
    $img = $date . md5 ( $source . $text1 . $text2 . $text3 ) . '.jpg';
    if (file_exists ( './' . $img )) {
        return $img;
    }
 
    $main = imagecreatefromjpeg ( $source );
 
    $width = imagesx ( $main );
    $height = imagesy ( $main );
 
    $target = imagecreatetruecolor ( $width, $height );
 
    $white = imagecolorallocate ( $target, 255, 255, 255 );
    imagefill ( $target, 0, 0, $white );
 
    imagecopyresampled ( $target, $main, 0, 0, 0, 0, $width, $height, $width, $height );
 
    $fontSize = 18;//像素字体
    $fontColor = imagecolorallocate ( $target, 255, 0, 0 );//字的RGB颜色
    $fontBox = imagettfbbox($fontSize, 0, $font, $text1);//文字水平居中实质
    imagettftext ( $target, $fontSize, 0, ceil(($width - $fontBox[2]) / 2), 190, $fontColor, $font, $text1 );
 
    $fontBox = imagettfbbox($fontSize, 0, $font, $text2);
    imagettftext ( $target, $fontSize, 0, ceil(($width - $fontBox[2]) / 2), 370, $fontColor, $font, $text2 );
 
    $fontBox = imagettfbbox($fontSize, 0, $font, $text3);
    imagettftext ( $target, $fontSize, 0, ceil(($width - $fontBox[2]) / 2), 560, $fontColor, $font, $text3 );
 
    //imageantialias($target, true);//抗锯齿，有些PHP版本有问题，谨慎使用
 
    imagefilledpolygon ( $target, array (10 + 0, 0 + 142, 0, 12 + 142, 20 + 0, 12 + 142), 3, $fontColor );//画三角形
    imageline($target, 100, 200, 20, 142, $fontColor);//画线
    imagefilledrectangle ( $target, 50, 100, 250, 150, $fontColor );//画矩形
 
    //bof of 合成图片
    $child1 = imagecreatefromjpeg ( 'http://gtms01.alicdn.com/tps/i1/T1N0pxFEhaXXXxK1nM-357-88.jpg' );
    imagecopymerge ( $target, $child1, 0, 400, 0, 0, imagesx ( $child1 ), imagesy ( $child1 ), 100 );
    //eof of 合成图片
 
    @mkdir ( './' . $date );
    imagejpeg ( $target, './' . $img, 95 );
 
    imagedestroy ( $main );
    imagedestroy ( $target );
    imagedestroy ( $child1 );
    return $img;
}
//http://my.oschina.net/cart/
generateImg ( 'http://1.popular.sinaapp.com/munv/pic.jpg', 'my.oschina.net/cart', 'PHP文字水平居中', '3个字' );
exit ();