Is it possible to swipe a specific color with an Image using PHP GD Library?

Question

I would like to know if is it possible to swipe a specific color with an Image.

I would use this if I wanted to change the color:

$imgname = "http://i.imgur.com/a94EGj9.png";
$im = imagecreatefrompng ($imgname);

imagetruecolortopalette($im,false, 255);

$index = imagecolorclosest ( $im,  21,194,37 ); // get color
imagecolorset($im,$index,255,255,255); // SET NEW COLOR

$time = time();

$imgname = "img".$time.".png";
imagegif($im, $imgname ); 
imagedestroy($im);

echo "<img src='".$imgname."' width='500' height='500' >";

But I want to change the background with an image.

Example, I downloaded a image of a room, and I painted the ground.

http://i.imgur.com/a94EGj9.png

I would like to know if I can remove the green ground and insert an image in there, like this:

http://i.imgur.com/sXWXkJ5.jpg

Is it possible to do that?

Thank you.

Answer 1

You probably want to use imagecopymerge, with 100 alpha.

$background_layer = imagecreatefrompng('image_background.png');

$imgname = "http://i.imgur.com/a94EGj9.png";

$im    = imagecreatefrompng ($imgname);
$color = imagecolorallocate($im, 21, 194, 37);
imagecolortransparent($im, $color);

imagecopymerge($background_layer, $im, 0, 0, 0, 0, imagesx($im), imagesy($im), 100);

header("Content-Type: image/png");
imagepng($background_layer);