如何在PHP中克隆gd资源

Question

我正在寻找用PHP imagecreatetruecolor或其他图像创建功能创建的PHP克隆图像.

正如在评论中所说,不,你不能做一个简单的感情,如:

$copy = $original;

这是因为ressources是引用,无法像标量值那样被复制.

示例:

$a = imagecreatetruecolor(10,10);
$b = $a;

var_dump($a, $b);

// resource(2, gd)

// resource(2, gd)

Answer 1

这个小函数将克隆图像资源,同时保留alpha通道(透明度).

function _clone_img_resource($img) {

  //Get width from image.
  $w = imagesx($img);
  //Get height from image.
  $h = imagesy($img);
  //Get the transparent color from a 256 palette image.
  $trans = imagecolortransparent($img);

  //If this is a true color image...
  if (imageistruecolor($img)) {

    $clone = imagecreatetruecolor($w, $h);
    imagealphablending($clone, false);
    imagesavealpha($clone, true);
  }
  //If this is a 256 color palette image...
  else {

    $clone = imagecreate($w, $h);

    //If the image has transparency...
    if($trans >= 0) {

      $rgb = imagecolorsforindex($img, $trans);

      imagesavealpha($clone, true);
      $trans_index = imagecolorallocatealpha($clone, $rgb['red'], $rgb['green'], $rgb['blue'], $rgb['alpha']);
      imagefill($clone, 0, 0, $trans_index);
    }
  }

  //Create the Clone!!
  imagecopy($clone, $img, 0, 0, 0, 0, $w, $h);

  return $clone;
}

Answer 2

所以,找到的解决方案是在评论中,这是它在Image管理类中的实现:

public function __clone() {
    $original = $this->_img;
    $copy = imagecreatetruecolor($this->_width, $this->_height);

    imagecopy($copy, $original, 0, 0, 0, 0, $this->_width, $this->_height);

    $this->_img = $copy;
}