Merge JPEG and PNG with transparent Background to one Image PHP - php

Question

i have the following script for coping a JPEG and a PNG to an existing PNG called base.png. Within the function "transparent_background" i replace the white background with transparency. This function is the problem. Standlone the function is working with output directly in the browser. please see the comment out "//imagepng($img);". but if i return the $img out of the function its still a jpeg i think, thats why it isnt transparent. The second function is just for resize.
<?php
function transparent_background($img)
{
$img = imagecreatefromjpeg($img); //or whatever loading function you need
$colors= array("255","255","255");
$remove = imagecolorallocate($img, $colors[0], $colors[1], $colors[2]);
imagecolortransparent($img, $remove);
//imagepng($img);
return $img;
imagedestroy($img);
}
function resize($img, $w){
$img = imagecreatefromjpeg($img);
$ratio = imagesx($img)/imagesy($img);
if( $ratio > 1) {
$width = $w;
$height = $w/$ratio;
}
else {
$width = $w*$ratio;
$height = $w;
}
$dst = imagecreatetruecolor($width,$height);
imagecopyresampled($dst,$img,0,0,0,0,$width,$height,imagesx($img),imagesy($img));
return $dst;
imagedestroy($dst);
imagedestroy($img);
}
$h="https://images-eu.ssl-images-amazon.com/images/I/415zYwg2-TL.jpg";
$base = imagecreatefrompng("base.png");
$logo = imagecreatefrompng("fs_logo_line.png");
$pos1=resize($h,"730");
$pos1=transparent_background($h);
imagecopy($base,$pos1,0, 5, 0, 0, imagesx($pos1),imagesy($pos1));
imagecopy($base,$logo,0, 1136, 0,0,imagesx($logo),imagesy($logo));
imagepng($base);
?>
I think the problem is, that i get a jpeg back from the transparent_background function and thats why the image in $pos1 is not transparent. Any ideas how i can solve that? I have tried with ob_start & ob_get_contents but this also didn't work.

Answer 1

You can merge the two images together using the PHP GD2 library.
Example:
<?php
# If you don't know the type of image you are using as your originals.
$image = imagecreatefromstring(file_get_contents($your_original_image));
$frame = imagecreatefromstring(file_get_contents($your_frame_image));
# If you know your originals are of type PNG.
$image = imagecreatefrompng($your_original_image);
$frame = imagecreatefrompng($your_frame_image);
imagecopymerge($image, $frame, 0, 0, 0, 0, 50, 50, 100);
# Save the image to a file
imagepng($image, '/path/to/save/image.png');
# Output straight to the browser.
imagepng($image);
?>
Add imagealphablending($frame,true); before imagecopymerge() if you want to keep PNG frame transparancy over the image.