PHP GD - Add a color layer over a image

Question

I want to add a color layer over a image in php using gd.

This is the image:

I want to overlay this with this color: #ABD0D2

I made a quick image how it should look at the end. Keep in mind that the image should still be transparent

So far I have this code:

$img = imagecreatefrompng('image.png');

imagesavealpha($img, true);
imagefill($img, 0, 0, imagecolorallocatealpha($img, 0, 0, 0, 127));

// make overlay with new color???

imagepng($img, 'new.png');
imagedestroy($img);

Answer 1

You can create a new image, filled with your target colour, and then merge the two:

$img = imagecreatefrompng('image.png');
$w = imagesx($img);
$h = imagesy($img);
imagesavealpha($img, true);

$img2 = imagecreatetruecolor($w, $h);
imagefill($img2, 0, 0, imagecolorallocatealpha($img, 0xAB, 0xD0, 0xD2, 64));

imagecopy($img, $img2, 0, 0, 0, 0, $w, $h);

imagepng($img, 'new.png');
imagedestroy($img);
imagedestroy($img2);

Result:

It's not completely clear to me how you want to maintain transparency (as your expected result image isn't transparent) so in the code above I've set the 'mask' colour at 50% opacity.

Answer 2

That worked for me:

    $width = 400;
    $height = 400;
    $image = imagecreatefrompng('img.png');

    $blueOverlay = imagecreatetruecolor($width, $height);
    imagesavealpha($image, true);
    imagealphablending($image, false);
    imagesavealpha($blueOverlay, true);
    $blue = imagecolorallocatealpha($blueOverlay, 0, 0, 255, ceil(0.22 * 127));
    imagefill($blueOverlay, 0, 0, $blue);
    imagecopymerge($blueOverlay, $image, 0, 0, 0, 0, $width, $height, 70);

    imagepng($blueOverlay, 'imgWithOverlay.png');
    imagedestroy($image);
    imagedestroy($blueOverlay);