Creating a Magic Wand tool in a photo editing application? (exactly the same as the Photoshop app)

Question

Is there a way to create a magic wand tool in the same way as the one in the Photoshop application, with an easier approach to the “color key”? it is very difficult, I searched a lot and did not get anything that I could make it work. Is there any library or simpler approach to achieve this? Any help is appreciated.