extension.js

'use strict';
const Gio = imports.gi.Gio;
const St = imports.gi.St;

const unlock = imports.ui.unlockDialog;
const Main = imports.ui.main;
const background = imports.ui.background;
const init_opacity = background.ANIMATION_OPACITY_STEP_INCREMENT 
const init_wakeup = background.ANIMATION_MIN_WAKEUP_INTERVAL
const ExtensionUtils = imports.misc.extensionUtils;
let settings = null;

class Extension{
	constructor(){
	}
	
	enable(){
		settings = ExtensionUtils.getSettings('org.gnome.shell.extensions.speedbackground');
		
		background.ANIMATION_OPACITY_STEP_INCREMENT = OPACITY_STEP.get();
		background.ANIMATION_MIN_WAKEUP_INTERVAL = WAKEUP_INTERVAL.get();
	}
	
	disable(){
		settings = null;

		background.ANIMATION_OPACITY_STEP_INCREMENT = init_opacity;
		background.ANIMATION_MIN_WAKEUP_INTERVAL = init_wakeup;
    
    // this extension uses both user and unlock-dialog session modes
    // this is done so that the higher refresh rate is retained in the lock-settings
    // without this, there would be a very jarring transition when locking, a high frame rate background will suddenly drop, causing it to skip frames and look quite ugly
	}
}


function init() {
	return new Extension();
}

//get from schemas
this.OPACITY_STEP = {
    key: 'opacity-step',
    get: function () {
        return settings.get_double(this.key);
    }
};
this.WAKEUP_INTERVAL = {
    key: 'wakeup-interval',
    get: function () {
        return settings.get_double(this.key);
    }
};