How to clone a gd resource in PHP

Question

I'm looking for image cloning in PHP created using imagecreatetruecolor or some other image creation function.

As the comment said, no, you cannot do simple attachment like:

 $copy = $original; 

This is because ressources are referenced and cannot be copied as scalar values.

Example:

 $a = imagecreatetruecolor(10,10); $b = $a; var_dump($a, $b); // resource(2, gd) // resource(2, gd) 

Answer 1

So, the solution found was in a comment, and this is its implementation in the image management class:

 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; } 

Answer 2

This small feature will clone the image resource while preserving the alpha channel (transparency).

 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 3

Simpler code, one line, descriptor transparency:

 function clone_img_resource($img) { return imagecrop($img, array('x'=>0,'y'=>0,'width'=>imagesx($img),'height'=>imagesy($img))); }