微信公众号 PDF 导出脚本

方便地导出公众号文章中以图片形式上传的试卷,让您一键开卷!

当前为 2022-11-09 提交的版本,查看 最新版本

您需要先安装一个扩展,例如 篡改猴Greasemonkey暴力猴,之后才能安装此脚本。

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

您需要先安装一个扩展,例如 篡改猴暴力猴,之后才能安装此脚本。

您需要先安装一个扩展,例如 篡改猴Userscripts ,之后才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey,才能安装此脚本。

您需要先安装用户脚本管理器扩展后才能安装此脚本。

(我已经安装了用户脚本管理器,让我安装!)

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

(我已经安装了用户样式管理器,让我安装!)

// ==UserScript==
// @name                微信公众号 PDF 导出脚本
// @namespace           mem.ac/weixin-print-to-pdf
// @version             1.4.2
// @description         方便地导出公众号文章中以图片形式上传的试卷,让您一键开卷!
// @author              memset0
// @license             AGPL-v3.0
// @match               https://mp.weixin.qq.com/s*
// @updateurl           https://cdn.jsdelivr.net/gh/memset0/weixin-print-to-pdf/index.js
// @downloadurl         https://cdn.jsdelivr.net/gh/memset0/weixin-print-to-pdf/index.js
// @run-at              document-start
// ==/UserScript==

const CSS = `
    .mem-print-container {
    }
    .mem-print-settings {
        margin: auto;
        padding: 16px;
    }
    .mem-print-settings-btn-group button {
        margin-right: 6px;
    }
    #mem-print-main {
        line-height: 0px;
        margin-bottom: 20px;
        /* padding: 16px;
        border: 1px solid #D9DADC; */
    }
    #mem-print-main button {
        margin-right: 8px;
    }
`;

function log(...args) {
    console.log('[@memset0/weixin-print-to-pdf]', ...args);
}

function isInteger(value) {
    const converted = +value;
    return !isNaN(converted) && Number.isInteger(converted);
}

function applyFilter(iterable, filterPattern) {
    const illegalFilter = (msg) => (alert('Illegal filter: ' + String(msg)), []);
    const flag = [];
    for (const _ in iterable) {
        flag.push(false);
    }
    if (!filterPattern || filterPattern == '-') {
        for (const i in flag) {
            flag[+i] = true;
        }
    } else {
        const filters = filterPattern.split(',');
        for (const filter of filters) {
            if (filter.includes('-')) {
                const splited = filter.split('-');
                if (splited.length > 2) {
                    return illegalFilter('wrong interval');
                }
                if (!splited[0]) {
                    splited[0] = 0;
                }
                if (!splited[1]) {
                    splited[1] = iterable.length - 1;
                }
                if (!isInteger(splited[0]) || !isInteger(splited[1])) {
                    return illegalFilter('not a number');
                }
                for (let i = +splited[0] - 1; i < +splited[1]; i++) {
                    if (i < 0 || i >= flag.length) {
                        return illegalFilter('out of range');
                    }
                    flag[i] = true;
                }
            } else {
                if (!isInteger(filter)) {
                    return illegalFilter('not a number');
                }
                const x = +filter - 1;
                if (x < 0 || x >= flag.length) {
                    return illegalFilter('out of range');
                }
                flag[x] = true;
            }
        }
    }
    log('apply filter:', filter, flag);
    const result = [];
    for (const i in iterable) {
        if (flag[+i]) {
            result.push(iterable[+i]);
        }
    }
    return result;
}

function scrollTo(type) {
    const scrollSpeed = 50;

    if (type !== 'top' && type !== 'bottom') { throw new Error('type error!'); }

    const scrollHeight = document.documentElement.scrollHeight || document.body.scrollHeight;
    let promiseResolve = null;
    let lastTimestamp = null;
    let scrollRecords = [];

    function scrollAnimated(timestamp) {
        const currentScroll = document.documentElement.scrollTop || document.body.scrollTop;
        scrollRecords.push(currentScroll);
        if (scrollRecords.length > 5) {
            scrollRecords.shift();
            let finishedFlag = true;
            for (let i = 1; i < scrollRecords.length; i++) {
                if (scrollRecords[i] !== scrollRecords[i - 1]) {
                    finishedFlag = false;
                    break;
                }
            }
            if (finishedFlag) {
                // log('finish', scrollRecords, finishedFlag);
                return promiseResolve(type);
            }
        }

        if (lastTimestamp === null) {
            lastTimestamp = timestamp;
        } else {
            const deltaTimestamp = timestamp - lastTimestamp;
            lastTimestamp = timestamp;
            window.scrollTo(0, currentScroll + scrollSpeed * (type === 'top' ? -deltaTimestamp : +deltaTimestamp));
            log(type, currentScroll, scrollHeight, deltaTimestamp);
        }
        window.requestAnimationFrame(scrollAnimated);
    }

    return new Promise((resolve) => {
        promiseResolve = resolve;
        window.requestAnimationFrame(scrollAnimated);
    });
}

async function printToPdf(width, height, margin, html) {
    log('print to pdf', width, height, margin);
    // await scrollTo('top');
    // await scrollTo('bottom');
    const pixeledMargin = String(margin).split(' ').map((s) => (s + 'px')).join(' ');
    const printStyle =
        '<style> /* normalize browsers */ html, body { margin: 0 !important; padding: 0 !important; } </style>' +
        '<style> /* page settings */ @page { size: ' + width + 'px ' + height + 'px; margin: ' + pixeledMargin + '; } </style>' +
        '<style> div.page { width: ' + (width - margin * 2) + 'px; height: ' + (height - margin * 2) + 'px; } </style>';
    html = printStyle + html;

    // const document = unsafeWindow.document;   // seemingly needless
    const blob = new Blob([html], { type: 'text/html;charset=utf-8' });
    const blobUrl = URL.createObjectURL(blob);
    log('blob url:', blobUrl);

    const $iframe = document.createElement('iframe');
    $iframe.style.display = 'none';
    $iframe.src = blobUrl;
    document.body.appendChild($iframe);
    $iframe.onload = () => {
        setTimeout(() => {
            $iframe.focus();
            $iframe.contentWindow.print();
        }, 1);
    };
}

function generateHtmlFromContent(options) {
    let html = '';
    for (const $element of applyFilter(document.getElementById('js_content').children, options.filter)) {
        console.log($element);
        html += $element.outerHTML + '\n\n';
    }
    return html;
}

function generateHtmlFromPictures(options) {
    const minimalImageSize = 100;

    let html = '<style>' +
        'div.page { page-break-after: always; display: flex; justify-content: center; align-items: center; }' +
        'div.page>img { width: 100%; max-width: 100%; max-height: 100%; }' +
        'div.page>img { border: solid 1px #fff0; } /* this line is magic */' +
        '</style>';
    for (const $image of applyFilter(document.getElementById('js_content').querySelectorAll('img'), options.filter)) {
        const imageSrc = $image.getAttribute('data-src');
        const imageWidth = $image.getAttribute('width');
        if (!imageSrc) { continue; }
        if (imageWidth && imageWidth < minimalImageSize) { continue; }
        html += '<div class="page"><img src="' + imageSrc + '"></div>';
        // log(imageWidth, imageSrc);
    }
    return html;
}

class Settings {
    createElement() {
        this.$inputs = {};

        const $dialog = document.createElement('dialog');
        $dialog.innerHTML = '<h1 class="mem-print-settings-title">Settings</h1>';
        $dialog.className = 'mem-print-settings';

        for (const name of Object.keys(this.defaults)) {
            const $label = document.createElement('label');
            const $input = document.createElement('input');
            this.$inputs[name] = $input;

            $label.innerText = name;
            if (this.defaults[name] !== '') {
                $label.innerText += '(default: ' + this.defaults[name] + ')'
            }
            $label.innerText += ':  ';

            $input.name = name;
            $input.value = this.data[name];
            $input.onblur = (event) => {
                log('update', $input.name, $input.value);
                this.updates[$input.name] = $input.value;
            };

            $label.appendChild($input);
            $dialog.appendChild($label);
            $dialog.appendChild(document.createElement('br'));
        }

        const $btnGroup = document.createElement('div');
        $btnGroup.className = 'mem-print-settings-btn-group';
        $dialog.appendChild($btnGroup);

        const $resetButton = document.createElement('button');
        $resetButton.innerText = 'Reset';
        $resetButton.name = 'reset';
        $resetButton.onclick = () => this.closeWindow(this.defaults);
        $btnGroup.appendChild($resetButton);

        const $cancelButton = document.createElement('button');
        $cancelButton.innerText = 'Cancel';
        $cancelButton.name = 'cancel';
        $cancelButton.onclick = () => this.closeWindow({});
        $btnGroup.appendChild($cancelButton);

        const $submitButton = document.createElement('button');
        $submitButton.innerText = 'Submit';
        $submitButton.name = 'submit';
        $submitButton.onclick = () => this.closeWindow(this.updates);
        $btnGroup.appendChild($submitButton);

        return $dialog;
    }

    openWindow() {
        this.updates = {};
        for (const name in this.$inputs) {
            // log('dialog open:', name, this.data[name], this.$inputs[name].value);
            this.$inputs[name].value = this.data[name];
        }
        this.$element.showModal();
    }

    closeWindow(update = null) {
        if (update && Object.keys(update).length) {
            for (const key in update) {
                this.data[key] = update[key];
            }
            localStorage.setItem(this.storageKey, JSON.stringify(this.data));
        }
        log('dialog closed:', update, this.data);
        this.$element.close();
    }

    constructor(storageKey = 'mem-print-settings') {
        this.storageKey = storageKey;
        this.data = {};
        this.defaults = {
            // Page Settings
            width: 797,   // A4 8.3inch * 11.7inch
            height: 1123,
            margin: 0,
            zoom: 1,
            // Element filters
            filter: '',
        };
        if (localStorage.getItem(storageKey)) {
            const storaged = localStorage.getItem(storageKey);
            if (storaged) {
                this.data = JSON.parse(storaged);
            }
        }
        for (const key in this.defaults) {
            if (!Object.keys(this.data).includes(key)) {
                this.data[key] = this.defaults[key];
            }
        }

        this.$element = this.createElement();
        document.body.appendChild(this.$element);
        if (typeof this.$element.showModal !== 'function') {
            this.$element.hidden = true;
            alert('Your browser doesn\'t support <dialog>, settings may not work.')
        }
    }
}

async function main() {
    function generateDiv(id, className) {
        const $div = document.createElement('div');
        $div.id = id;
        $div.className = className;
        return $div;
    }
    function generateButton(buttonName, callback) {
        const $btn = document.createElement('button');
        $btn.innerText = buttonName;
        $btn.style = 'padding-left: 4px; padding-right: 4px;'
        $btn.onclick = () => {
            log('Triggered by', [buttonName], $btn);
            callback();
        }
        return $btn;
    }

    const settings = new Settings();
    log(settings.data);

    $mainContainer = generateDiv('mem-print-main', 'mem-print-container');
    $sideContainer = generateDiv('mem-print-side', 'mem-print-container');

    $style = document.createElement('style');
    $style.innerHTML = CSS;
    $mainContainer.appendChild($style);

    document.getElementsByClassName('qr_code_pc')[0].appendChild($sideContainer);
    document.getElementById('img-content').parentNode.insertBefore($mainContainer, document.getElementById('img-content'));
    console.log($mainContainer, $sideContainer);

    printContent = () => {
        printToPdf(settings.data.width, settings.data.height, settings.data.margin, generateHtmlFromContent(settings.data));
    }
    $mainContainer.appendChild(generateButton('Print Content', printContent));
    $sideContainer.appendChild(generateButton('Print Content', printContent));

    printPictures = () => {
        printToPdf(settings.data.width, settings.data.height, settings.data.margin, generateHtmlFromPictures(settings.data));
    };
    $mainContainer.appendChild(generateButton('Print Pictures', printPictures));
    $sideContainer.appendChild(generateButton('Print Pictures', printPictures));

    $mainContainer.appendChild(generateButton('Settings', () => { settings.openWindow(); }));
    $sideContainer.appendChild(generateButton('Settings', () => { settings.openWindow(); }));
}

document.addEventListener('DOMContentLoaded', main);