Image Coordinate Detecter for Processing

There are tools on the web where you can submit a picture and the website will detect ‘points’ and outline your image so you can use them for the canvas HTML tag to draw animation. Is there any type of tool like this for Processing?
Heres an example: If I submit an image of an apple maybe I will get a line that starts at 100,200 and then the next line is 200,300 or something like that.
Example to website mentioned: https://www.mobilefish.com/services/record_mouse_coordinates/record_mouse_coordinates.php

As I understand the website mentioned, this is really easy. Just record mouseX, mouseY in mousePressed(), using an array. (I would use a PVector ArrayList).
You can also automate the process using the openCV object detection. You could change the code of this example.