第二个imagemagick命令上的exec（）权限被拒绝

Question

我无法弄清楚这一点，我运行以下命令，第一个工作正常，然后我运行第二个，我得到许可被拒绝。我尝试过使用chmod()但这不起作用，我很难过......

// This line works:
exec("$this->convert '$this->background' -resize 250 '$this->name'", $opt);

// This line gives permission denied:
exec("$this->mogrify xc:black -font '$font' -pointsize $font_size -draw \"text 240,10 '5'\" '$this->name'", $opt);

这是一个更好的外观：

protected $convert    = "/usr/local/bin/convert";
protected $mogrify    = "/usr/local/bin/mogrify";

public function display($format = Turing::JPG, $quality = 100){
    // Create an image with a random background
    exec("$this->convert '$this->background' -resize 250 '$this->name'", $opt);
    $this->_buildText();
}

protected function _buildText(){
    $text = $this->turing;
    for($i = 0; $i < strlen($text); $i++){
        $font      = $this->getFont();
        $angle     = $this->getAngle();
        $font_size = $this->getFont(35, 45);
        if(stripos($font, "Kidnap_Note") !== false){
            $font_size = $this->getFont(45, 50);
        }
        $x = (40 - ($this->step / 2) + $i * 45);
        $y = 50;
        $opt = null;
        exec($q="$this->convert '$this->name' xc:black -font '$font' -pointsize $font_size -draw \"text 240,10 '{$text[$i]}'\" '$this->name'", $opt);
    }
}