Replace the specific RGB color with another image using PHP

Question

I derived a perfect color replace script from https://stackoverflow.com/a/32710756/1620626. I want to replace the target color with the image background. The original image is b

Answer 1

You can just read two images, source and background, and take pixels from background image and set to the source.

Below is the last part of your code above which shows this idea:

$filename = 'images/01.png';
$bgFilename = 'images/background.png';
$im = imagecreatefrompng($filename);
$bg = imagecreatefrompng($bgFilename);
$out = imagecreatetruecolor(imagesx($im), imagesy($im));
$transColor = imagecolorallocatealpha($out, 254, 254, 254, 127);
imagefill($out, 0, 0, $transColor);

for ($x = 0; $x < imagesx($im); $x++) {
    for ($y = 0; $y < imagesy($im); $y++) {
        $pixel = imagecolorat($im, $x, $y);
        $bgPixel = imagecolorat($bg, $x, $y);

        $red = ($pixel >> 16) & 0xFF;
        $green = ($pixel >> 8) & 0xFF;
        $blue = $pixel & 0xFF;
        $alpha = ($pixel & 0x7F000000) >> 24;
        $colorHSL = RGBtoHSL($red, $green, $blue);

        if ((($colorHSL[0]  >= $colorToReplace[0] - $hueAbsoluteError) && ($colorToReplace[0] + $hueAbsoluteError) >= $colorHSL[0])){
            // Instead of taking the replacementColor
            /* $color = HSLtoRGB($replacementColor[0], $replacementColor[1], $colorHSL[2]); */
            /* $red = $color[0]; */
            /* $green= $color[1]; */
            /* $blue = $color[2]; */
            // We just take colors from the backround image pixel
            $red = ($bgPixel >> 16) & 0xFF;
            $green = ($bgPixel >> 8) & 0xFF;
            $blue = $bgPixel & 0xFF;
        }

        if ($alpha == 127) {
            imagesetpixel($out, $x, $y, $transColor);
        }
        else {
            imagesetpixel($out, $x, $y, imagecolorallocatealpha($out, $red, $green, $blue, $alpha));
        }
    }
}
imagecolortransparent($out, $transColor);
imagesavealpha($out, TRUE);
header('Content-type: image/png');
imagepng($out);

The result can look like this: