小程序码更换中间logo--php生成函数

public function makeimg()
    {   
        $path_1 = 'uploads/seven.png';
        $path_2 = 'http://wx.qlogo.cn/mmopen/PiajxSqBRaEJibOmQsOZ3fUUNscz3v592BKwCjnC3HYHHnMibuQ5pGo1KrsPruYNMmmZKiaKNoV7cp7biciarqWBQreA/0';  
        if(!file_exists("uploads/wxcode/")) {
            mkdir("uploads/wxcode/", 0755, true);
        }
        $file_name = "uploads/wxcode/".time().".png"; 
        $codeimg = imagecreatefromstring(file_get_contents($path_1));
        $src_img = imagecreatefromstring(file_get_contents($path_2));
        $w = $h = min(imagesx($src_img), imagesy($src_img));
        $newwidth = $newheight = 192;
        $img = imagecreatetruecolor($w, $h);
        imagesavealpha($img, true);
        $bg = imagecolorallocatealpha($img, 255, 255, 255, 127);
        imagefill($img, 0, 0, $bg);
        $r = $w / 2;
        for ($x = 0; $x < $w; $x++) {
            for ($y = 0; $y < $h; $y++) {
                $rgbColor = imagecolorat($src_img, $x, $y);
                if (((($x - $r) * ($x - $r) + ($y - $r) * ($y - $r)) < ($r * $r))) {
                    imagesetpixel($img, $x, $y, $rgbColor);
                }
            }
        }
        $newimg = imagecreatetruecolor($newwidth, $newheight);
        imagesavealpha($newimg, true);
        $color = imagecolorallocatealpha($newimg, 255, 255, 255, 127); 
        //$color = imagecolorallocate($newimg,255,255,255);
        imagefill($newimg, 0, 0, $color);
        imageColorTransparent($newimg, $color);
        imagecopyresampled($newimg, $img, 0, 0, 0, 0, $newwidth, $newheight, imagesx($img), imagesy($img));
        imagecopymerge($codeimg, $newimg, 119, 119, 0, 0, imagesx($newimg), imagesy($newimg), 100);
        imagepng($codeimg,$file_name); 
        response_ok($file_name);
    }