Plugin installation without composer?

Hi everyone
Do you have a method to install a plugin that need to be installed with composer manually ?
More specifically, I’m trying to install the dominant color extractor.
After my extraction of dominantcolor folder into plugins I have the message : require 'vendor/autoload.php';

I’m not really interested to install composer and using it, so I’m wondering if I could place the autoload.php somewhere ? This could be usefull for newbie like me, and other plugins.

I just created a fork with dependencies included:

Let me know if it works.

Alternatively, you could download all dependencies manually and require them in the main file.

Yes, it’s working very good ! Thanks.
I know now how to avoid composer.