《假装水墨屏》让网页内容变成水墨屏效果

墨水屏相当于把屏幕彩色变成了舒适的黑白，眼睛会舒服一些。

往油猴编辑器中粘贴脚本后，按Ctrl+s键即可保存，自动跳转到脚本列表页面，然后刷新页面，脚本即刻生效。

// ==UserScript==
// @name        假装水墨屏
// @name:en-US  Fake Ink Screen
// @namespace   Fake Ink Screen
// @match       *://*/*
// @grant       GM_addStyle
// @grant       GM_getValue
// @grant       GM_setValue
// @grant       GM_deleteValue
// @grant       GM_registerMenuCommand
// @run-at      document-start
// @inject-into content
// @version     0.2.3
// @author      稻米鼠
// @created     2020-07-24 13:02:56
// @updated     2020-08-10 18:51:07
// @description 假装用的水墨屏，阅读不累眼（可能吧）。最新加入彩色&反色水墨屏模式，在脚本菜单中切换。
// ==/UserScript==

(function(){
// 闭包 Start
GM_addStyle(`
  html.gray-ink-screen {
    -webkit-filter: grayscale(100%) brightness(120%);
    -moz-filter: grayscale(100%) brightness(120%);
    -ms-filter: grayscale(100%) brightness(120%);
    -o-filter: grayscale(100%) brightness(120%);
    filter: grayscale(100%) brightness(120%);
  }
  html.dark-ink-screen {
    -webkit-filter: grayscale(100%) brightness(120%) invert(100%);
    -moz-filter: grayscale(100%) brightness(120%) invert(100%);
    -ms-filter: grayscale(100%) brightness(120%) invert(100%);
    -o-filter: grayscale(100%) brightness(120%) invert(100%);
    filter: grayscale(100%) brightness(120%) invert(100%);
  }
  html.color-ink-screen {
    -webkit-filter: saturate(60%) contrast(160%);
    -moz-filter: saturate(100%) contrast(160%);
    -ms-filter: saturate(60%) contrast(160%);
    -o-filter: saturate(60%) contrast(160%);
    filter: saturate(60%) contrast(160%);
  }
  html.gray-ink-screen,
  html.gray-ink-screen body,
  html.gray-ink-screen .ink-background,
  html.dark-ink-screen,
  html.dark-ink-screen body,
  html.dark-ink-screen .ink-background {
    background-color: rgb(200, 200, 200) !important
  }
  html.color-ink-screen,
  html.color-ink-screen body,
  html.color-ink-screen .ink-background {
    background-color: rgb(198, 198, 198) !important
  }
  html.dark-ink-screen .ink-font,
  html.gray-ink-screen .ink-font {
    color: rgb(66, 66, 66) !important
  }
  html.color-ink-screen .ink-font {
    color: rgb(98, 98, 98) !important
  }
  html.gray-ink-screen * {
    text-shadow: 0 0 1.2rem rgba(0, 0, 0, .24), 0 0 .5px rgba(0, 0, 0, .5)
  }
  html.color-ink-screen * {
    text-shadow: 0 0 1.2rem rgba(0, 0, 0, .2), 0 0 .5px rgba(0, 0, 0, .4)
  }
`);
const modes = ['gray-ink-screen', 'color-ink-screen', 'dark-ink-screen']
const toggleMode = (modeIndex)=>{
  for(const className of modes) {
    document.body.parentElement.classList.remove(className)
  }
  document.body.parentElement.classList.add(modes[modeIndex])
}
toggleMode(GM_getValue('mode', 0))
GM_registerMenuCommand('切换【黑白&彩色&反色】水墨屏',()=>{
  let mode = GM_getValue('mode', 0)
  mode = mode>=2 ? 0 : ++mode
  toggleMode(mode)
  GM_setValue('mode', mode)
})
window.addEventListener('load', () => {
  const inkEl = async(el) => {
    const fontColor = window.getComputedStyle(el).color.match(/\d+/g);
    const rgbVal = window.getComputedStyle(el).backgroundColor.match(/\d+/g);
    if(!fontColor || !rgbVal) return;
    if (
      fontColor &&
      +fontColor[0] + +fontColor[1] + +fontColor[2] > 255 &&
      +fontColor[0] + +fontColor[1] + +fontColor[2] < 588
    ) {
      el.classList.add('ink-font');
    }
    if (rgbVal[3] && rgbVal[3] === '0') return;
    if (
      (+rgbVal[0] + +rgbVal[1] + +rgbVal[2]) / (rgbVal[3] ? +rgbVal[3] : 1) >
      640
    )
      el.classList.add('ink-background');
  };
  document.body.querySelectorAll('*').forEach((el) =>  inkEl(el) );
  const obOptions = {
    childList: true,
    subtree: true,
    attributes: true,
    characterData: true,
    attributeOldValue: false,
    characterDataOldValue: false,
    attributeFilter: [],
  };
  const observer = new MutationObserver(async (records, observer) => {
    observer.disconnect();
    const els = records
      // 改变的类型为 characterData，并且不是 body 元素的话
      .filter((el) => /^characterData$/i.test(el.type))
      .map((el) => el.target); // 把发生改变的元素放入合集
    // 改变的类型为 childList，则把新增的元素放入合集
    records
      .filter((el) => /^childList$/i.test(el.type))
      .forEach((el) => {
        el.addedNodes.forEach((node) => els.push(node));
      });
    // 遍历合集中所有元素
    for await (el of els) {
      if(el.nodeType === 1) {
        inkEl(el);
        el.querySelectorAll('*').forEach(e=>inkEl(e))
      }
    }
    // 页面处理完成之后重新监控页面变化
    observer.observe(document.body, obOptions);
  });
  observer.observe(document.body, obOptions);
});
// 闭包 End
})()