White background replacer

Replaces the background white color with a darker one in order to decrease eye strain

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

'use strict';
// ==UserScript==
// @name         White background replacer
// @namespace    http://siavoshkc.com/
// @version      2.24
// @description  Replaces the background white color with a darker one in order to decrease eye strain
// @author       siavoshkc
// @match        *://*/*
// @grant        none
// @license      MIT
// @run-at       document-idle
// ==/UserScript==

const INTERVAL = 120000
const goodBgColors = ["#b0edc4", "#79d2a6", "#8EC4C6", "#79C664", "#79AC78","#74B6C0","#A19C6D", "#61B6A1", "#66C0A9",
                      "#7BA699", "#5E8784", "#71979E", "#4E8B57", "#7D8E92","#AF9D9D", "#95BBBB", "#7FB397", "#87B8A8",
                      "#D9BD7F", "#BDA279", "#A3AA70", "#9095A1", "#7CA870", "#8EB157,", "#7B765A", "#809582", "#7DA16F"]
const knownVarNames = ['--bg', '--bg-color', '--background-color', '--background', '--theme-content-background-color', '--lighting-color'
                       , '--theme-background-color', '--theme-content-background-color', '--background-color-base', '--color-neutral-000'
                       , '--custom-select-bg-color']

var currentGoodBgColor = 0

function isWhite(bg) {
    if(!bg) return
    const [rgba] = Array.from(bg.matchAll(/\(([0-9]+), ?([0-9]+), ?([0-9]+)(, ?([0-9]+))?.*\)/g))
    const hsl = bg.match(/hsl\(\s*(\d+)\s*,\s*(\d+(?:\.\d+)?%)\s*,\s*(\d+(?:\.\d+)?%)\)/)
    const hsla = bg.match(/hsla\(\s*(\d+)\s*,\s*(\d+(?:\.\d+)?%)\s*,\s*(\d+(?:\.\d+)?%)\s*,\s*((\.\d+)|1)\)/)
    bg = bg.toLowerCase()

    return (
        bg == "white" ||
        bg == "#ffffff" ||
        bg == "#fff" ||
        bg == "#fdfdfd" ||
        (hsl && Number(hsl[2].replace('%','')) > 89) ||
        (hsla && (Number(hsl[2].replace('%','')) > 89) && Number(hsl[3]) > .9) ||
        (rgba && ((+rgba[1] > 230 && +rgba[2] > 230 && +rgba[3] >230) || +rgba[5] === 0))
    )
}

function changeColor(style) {
    style.backgroundColor = goodBgColors[currentGoodBgColor % goodBgColors.length] + 'AF'
    if(style.color == style.backgroundColor) style.color = "black"
    if(currentGoodBgColor === Number.MAX_SAFE_INTEGER) currentGoodBgColor = 0
    else currentGoodBgColor++
    setTimeout(changeColor, INTERVAL, style)
}

function checkStyle(style, isComputed=false) {
    if(!style) return

    knownVarNames.forEach(v=> {
        if(isWhite(style.getPropertyValue(v)) ) {
            if(isComputed) return true
            style.setProperty(v, goodBgColors[currentGoodBgColor % goodBgColors.length] + 'AF')
        }
    })

    if(isWhite(style.background) || isWhite(style.backgroundColor)) {
        if(isComputed) return true
        changeColor(style)
    }
}

function iterateRules(cssRules) {
    if(!cssRules) return

    for (let rule of cssRules) {
        try {
            checkStyle(rule.style)
        } catch(e) { console.debug("WBR: Caught exception when checking rule style: ", e) }

        iterateRules(rule.cssRules)
    }
}

function checkPage() {
    var elems = document.getElementsByTagName("*");
    for (const el of elems) el.removeAttribute("bgcolor")
    //console.debug("White background replacer: Running...", window.getComputedStyle(document.documentElement));
    if(checkStyle(window.getComputedStyle(document.documentElement), true)){
       // let gst = window.getComputedStyle(document.documentElement)
       //  const filteredObject = Object.keys(gst).reduce(function(r, e) {
       // if (e.match(/.*back.*/)) r[e] = gst[e]
       //    return r;
       // }, {})
       // console.debug("Global background detected", filteredObject)
        try {
            const all = document.styleSheets,
                s = all[all.length - 1],
                l = s?.cssRules?.length || 0;
            if (s?.insertRule) {
                s.insertRule('body {background-color: DarkKhaki !important}', l)
                // console.debug("Global rule inserted")
            } else throw new Error("No insertRule")
        } catch(e) {
            // console.debug("WBR: Global change using new stylesheet failed. Appending element...: ", e)
            const s = document.createElement('style');
            s.innerHTML = 'body {background-color: Tan !important;}';
            document.body.appendChild(s);
            // console.debug("Global element appended")
        }
    }
    if(document.styleSheets?.length > 0) {
        for (const sheet of document.styleSheets) {
            try {
              iterateRules(sheet.cssRules)
            } catch(e) {
              console.error(e, sheet)
            }
        }
    }
}
checkPage()