Pattern option for ESP8266 Controlled Leds

Hello Everyone,

I applied a web based controller for my SMD5050 types RGB leds from below link.

And those are similar to my leds:

middle of the page there is "NodeMCU RGB LED Strip Mood Lamp Controller" section, that's what I applied. It works flawless but I want to add some patterns for LEDs, just simple things like breathing effects etc because as I know my LEDs aren't addressable.

So I figured out that I need to edit "index.h" web server file to add a button and function, that would be enough or how can I add a breathing or color changing patterns with modifying this project?

Thanks in advance.