php字符串生成图片、图片合成

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;
}

generateImg ( "https://ssl.picture.qingger.com/Fi8zMItS5c_Uvm7WueZ5z_0VsDg_", "aaaaa", "PHP文字水平居中", "3个字" );
exit ();