Smoothly scrolls the page when a button is held
// ==UserScript==
// @name Smooth Scrolling
// @description Smoothly scrolls the page when a button is held
// @version 1.1.2
// @author sllypper
// @homepage https://greasyfork.org/en/users/55535-sllypper
// @namespace https://greasyfork.org/en/users/55535-sllypper
// @match *://forums.spacebattles.com/*
// @match *://forums.sufficientvelocity.com/*
// @match *://forum.questionablequesting.com/*
// @match *://fanfiction.net/*
// @match *://archiveofourown.org/*
// @match *://turb0translation.blogspot.com/*
// @match *://fiction.live/*
// @grant none
// @todo make keybinds easily configurable
// ==/UserScript==
(function() {
'use strict';
// Smooth Scrolling Settings
// how much it scrolls every time (in pixels)
let scrollAmount = 16;
// how long between ticks (in ms)
// 16.66667 = 60 frames per second
// not used if experimental is true
let scrollPeriod = 16.66667;
// how much holding Shift will multiply the scrollAmount
let shiftSpeedMod = 2.0;
//
// Experimental settings
// Use the alternative experimental Scroller
// it's bound to your screen framerate
// is supposed to be smoother
let experimental = true;
// Scroll Speed in times per second
// set to 0 to match your refresh rate (smooth perfection)
// values above your framerate scrolls every frame
let fps = 0
// programming magic stuff
const states = {
NONE: 0,
UP: 1,
SHIFTUP: 2,
DOWN: 3,
SHIFTDOWN: 4
}
let scrollState = states.NONE;
let currScrollAction = null;
let isTyping = false;
document.addEventListener('focus', function(evt) {
var target = evt.target;
if((target.nodeName === 'INPUT' && target.type === 'text') || target.nodeName === 'TEXTAREA') isTyping = true;
// else isTyping = false;
}, true);
document.addEventListener('blur', function(evt) {
var target = evt.target;
if((target.nodeName === 'INPUT' && target.type === 'text') || target.nodeName === 'TEXTAREA') isTyping = false;
}, true);
document.addEventListener("keydown", event => {
// ignore keybindings when text input is focused
if (isTyping || event.isComposing || event.target.getAttribute('medium-editor') != null || event.target.getAttribute('contenteditable') != null) {
//console.log('entered first if')
event.stopPropagation();
return;
}
switch (event.code) {
case "KeyW":
case "KeyK":
case "ArrowUp": {
event.preventDefault();
if (scrollState !== states.UP && !event.shiftKey) {
//event.preventDefault();
clearScrollAction();
scrollState = states.UP;
scrollAction(-scrollAmount);
} else if (scrollState !== states.SHIFTUP && event.shiftKey) {
//event.preventDefault();
clearScrollAction();
scrollState = states.SHIFTUP;
scrollAction(-scrollAmount*shiftSpeedMod);
}
break;
}
case "KeyS":
case "KeyJ":
case "ArrowDown": {
event.preventDefault();
if (scrollState !== states.DOWN && !event.shiftKey) {
// event.preventDefault();
clearScrollAction();
scrollState = states.DOWN;
scrollAction(scrollAmount);
} else if (scrollState !== states.SHIFTDOWN && event.shiftKey) {
// event.preventDefault();
clearScrollAction();
scrollState = states.SHIFTDOWN;
scrollAction(scrollAmount*shiftSpeedMod);
}
break;
}
}
});
document.addEventListener("keyup", event => {
switch(event.code) {
case 'KeyW':
case 'KeyK':
case 'KeyJ':
case 'KeyS':
case 'ArrowDown':
case 'ArrowUp':
clearScrollAction();
break
default:
// using even.key for any Shift Key
if (event.key === "Shift") {
clearScrollAction();
}
break;
}
});
function scrollAction(amount) {
if (experimental) {
scroller.move(amount)
return;
}
currScrollAction = setInterval(() => {
window.scrollBy(0, amount);
}, scrollPeriod)
}
function clearScrollAction() {
clearInterval(currScrollAction);
currScrollAction = null;
scrollState = states.NONE;
scroller.stop();
}
// experimental bit
let scroller = new Scroller(fps)
function Scroller(fps) {
var delay,
time,
frame,
tref,
amount;
function loop(timestamp) {
if (fps !== 0) {
// Scroll with fps behavior
if (time === null) {time = timestamp; timestamp = 0}
var seg = Math.floor((timestamp - time) / delay);
if (seg > frame) {
frame = seg;
window.scrollBy(0, amount);
}
} else {
// Scroll every frame behavior
window.scrollBy(0, amount);
}
tref = requestAnimationFrame(loop)
}
this.move = function(pixels) {
amount = pixels;
delay = 1000 / fps;
frame = -1;
time = null;
tref = requestAnimationFrame(loop);
}
this.stop = function() {
cancelAnimationFrame(tref);
};
}
})();