Пример функции цвета фона обмена идентификационными фотографиями на основе PHP

php
//The background image and the original image need to keep the same width and height. The example original image here uses a blue background
init();
function init(){
  $old = '1.png';
  $new = '2.png';
  //Create a PNG transparent graph
  $img = imagecreatefrompng($old);
  setpng($img,$old,$new);
}
function setpng($imgid,$filename,$savename){
  $bg = ' bg.png '; // background image
  $new = imagecreatefrompng($bg);//Create a PNG transparent graph
  List ($width, $height) = getimagesize ($filename); // get the length and width
  $white = imagecolorallocate ($imgid, 1155215); // select a replacement color. This is green
  cleancolor($imgid,$white);
  Imagecolortransparent ($imgid, $white); // replace the selected color with transparent
  Imagecopymerge ($new, $imgid, 0,0,0,0, $width, $height, 100); // merge images
  Imagepng ($new, $savename); // save the image
  Imagedestroy ($imgid); // destroy
  imagedestroy($new);
  echo '';
}
function cleancolor($imgid,$color){
  $width = imagesx ($imgid); // get width
  $height = image ($imgid); // get high
  for($i=0;$i<$width;$i++){
    for($k=0;$k<$height;$k++){
      //Compare each pixel
      $rgb = imagecolorat($imgid,$i,$k);
      $r = ($RGB > > 16) & 0xff; // take R
      $g = ($RGB > > 8) & 0xff; // take G
      $B = $RGB & 0xff; // take B
      $randr = 1.5;
      $randg = 1;
      $randb=1;
      //The approximate position of the blue RGB. Replace with green
      if($r<=65*$randr && $g<=225*$randg && $b<=255*$randb && $b*$randb>=100){
        //If you can accurately calculate the position to be reserved, you can write absolute numbers here
        if($i>=$width/2 && $i<=$width/2 && $k>=$height/2 && $k<=$height/2){
          
        }else{
          //Change the color
          imagesetpixel($imgid,$i,$k,$color);
        }
      }
    }
  }
}