Fatal error: Uncaught Error: Call to undefined method Imagick::flattenImages() - imagemagick

Question

I have been using Imagick and ImageMagick in one of my Image processing scripts. It is working perfectly on my development server has the following configurations.
PHP Version 7.0.33
Imagick 3.4.3
ImageMagick 6.7.9-10 2016-05-05 Q16 http://www.imagemagick.org
But on my client's server, I am getting the following error.
Fatal error: Uncaught Error: Call to undefined method Imagick::flattenImages()
My client has the following configuration
PHP Version 7.2.15
Imagick 3.4.3
ImageMagick 7.0.7-11 Q16 x86_64 2017-11-20 http://www.imagemagick.org
I just wonder how the Imagick::flattenImages() is missing from my client's server as both my server and client's server has the same Imagick version

Answer 1

Try this:
$image = new Imagick();
$image->readImage( $path_to_file );
$flattenedImage = $img->mergeImageLayers( imagick::LAYERMETHOD_FLATTEN );
PHP docs for Imagick::mergeImageLayers() method
You can also pass one of these constants as a layer method:
imagick::LAYERMETHOD_UNDEFINED (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_COALESCE (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_COMPAREANY (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_COMPARECLEAR (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_COMPAREOVERLAY (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_DISPOSE (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_OPTIMIZE (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_OPTIMIZEPLUS (ImageMagick 6.2.9+)
imagick::LAYERMETHOD_OPTIMIZEIMAGE (ImageMagick 6.3.0+)
imagick::LAYERMETHOD_OPTIMIZETRANS (ImageMagick 6.3.0+)
imagick::LAYERMETHOD_REMOVEDUPS (ImageMagick 6.3.0+)
imagick::LAYERMETHOD_REMOVEZERO (ImageMagick 6.3.0+)
imagick::LAYERMETHOD_COMPOSITE (ImageMagick 6.3.0+)
imagick::LAYERMETHOD_MERGE (ImageMagick 6.3.7+)
imagick::LAYERMETHOD_FLATTEN (ImageMagick 6.3.7+)
imagick::LAYERMETHOD_MOSAIC (ImageMagick 6.3.7+)