Automatic generation of direct download PDF on Rain Classroom
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/* globals jspdf UPNG */
// ==UserScript==
// @name Rain Classroom PDF Direct Download
// @name:zh-CN 雨课堂课件PDF下载工具
// @namespace https://www.pizyds.com/
// @version 1.0.2
// @description Automatic generation of direct download PDF on Rain Classroom
// @description:zh-CN 在雨课堂页面自动生成PDF版本课件提供下载
// @author PillarsZhang
// @homepage https://www.pizyds.com/rain-classroom-pdf-direct-download
// @license MIT
// @match https://www.yuketang.cn/v2/web/student*
// @icon https://www.yuketang.cn/static/images/favicon.ico
// @require https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.3.1/jspdf.umd.min.js
// @require https://cdnjs.cloudflare.com/ajax/libs/pako/2.0.3/pako.min.js
// @require https://cdnjs.cloudflare.com/ajax/libs/upng-js/2.1.0/UPNG.min.js
// @resource pizyds_iconfont_css https://at.alicdn.com/t/font_2448118_l5d66dc50k9.css
// @grant GM_getResourceText
// @grant GM_addStyle
// ==/UserScript==
(function() {
'use strict';
//jsPDF用于PDF生成，UPNG、pako用于PNG的反交错和压缩
const {jsPDF} = jspdf;
//下载的图标，感谢iconfont
const pizyds_iconfont_css = GM_getResourceText("pizyds_iconfont_css");
GM_addStyle(pizyds_iconfont_css);
//实时查找PPT窗口
setInterval(()=>{
var el_dialog = find_basePPTDialog();
el_dialog && add_button_download(el_dialog);
},500);
//按钮触发PDF生成逻辑
function download_process(el_dialog){
var url_slides = get_url_slides(el_dialog);
if (url_slides.length > 0){
refreshProcessStatus("处理图片...");
image_process(url_slides)
.then(img_list => {
refreshProcessStatus("生成PDF...");
var ppt_name = document.getElementsByClassName("ppt_name")[0].innerText;
var filename = ppt_name + ".pdf";
pdf_process(img_list, filename);
refreshProcessStatus("下载课件");
})
} else{
alert("雨课堂课件PDF下载工具：没有提取到图片");
}
}
//第一步-借助UPNG，进行图片下载与反交错、压缩处理
function image_process(url_slides){
var promiseList = new Array(url_slides.length);
var finished_num = 0;
var count_finished_num = (index) => {
var processStatus = `${++finished_num}/${url_slides.length}`;
refreshProcessStatus(`处理图片(${processStatus})`);
console.log(`${processStatus} - 第${index+1}页 - ${url_slides[index]} - finished`);
}
for (let i = 0; i < url_slides.length; i++){
promiseList[i] = fetch(url_slides[i]).then(response => {
return response.arrayBuffer();
}).then(arrayBuffer_origin => {
var img = UPNG.decode(arrayBuffer_origin);
var rgba = UPNG.toRGBA8(img);
var arrayBuffer_compress = UPNG.encode(rgba, img.width, img.height, 0);
count_finished_num(i);
return {unit8: new Uint8Array(arrayBuffer_compress), width: img.width, height: img.height};
}).catch(err => {
console.error(err);
alert("雨课堂课件PDF下载工具：图像处理出错");
});
}
return Promise.all(promiseList);
}
//第二步-借助jsPDF，进行PDF的生成
function pdf_process(img_list, filename){
var doc = new jsPDF({
orientation: "landscape",
unit: "px",
format: [img_list[0].width, img_list[0].height],
hotfixes: ["px_scaling"]
});
doc.addImage(img_list[0].unit8, 'PNG', 0, 0, img_list[0].width, img_list[0].height);
for (let i = 1; i < img_list.length; i++){
doc.addPage([img_list[i].width, img_list[i].height], "landscape");
doc.addImage(img_list[i].unit8, 'PNG', 0, 0, img_list[i].width, img_list[i].height);
}
doc.save(filename);
}
//按钮文本刷新
function refreshProcessStatus(processStatus){
var el_download = document.getElementsByClassName("pizyds_download")[0];
el_download.innerHTML = `<i class="iconfont icon-pizyds-rain-down-xiazai"></i> ${processStatus}`;
}
//查找PPT窗口
function find_basePPTDialog(){
var el_dialogs = document.getElementsByClassName("basePPTDialog");
if (el_dialogs.length == 1){
return el_dialogs[0];
} else{
return false;
}
}
//PPT图片链接提取
function get_url_slides(el_dialog){
try{
var el_swiper = el_dialog.getElementsByClassName("pptSwiper")[0];
var el_slides = el_swiper.getElementsByClassName("swiper-slide");
var url_slides = new Array(el_slides.length);
for(let i = 0; i < el_slides.length; i++){
url_slides[i] = el_slides[i].getElementsByTagName("img")[0].src;
}
return url_slides;
} catch(err){
return new Array();
}
}
//按钮注入
function add_button_download(el_dialog){
var el_header = el_dialog.getElementsByClassName("layout_header")[0];
if (el_header.getElementsByClassName("pizyds_download").length == 0){
var el_download = create_node_from_html(`<span class="print pizyds_download" style="right:120px">
<i class="iconfont icon-pizyds-rain-down-xiazai"></i> 下载课件</span>`);
el_download.onclick = () => download_process(el_dialog);
el_header.appendChild(el_download);
return true;
} else{
return false;
}
}
//HTML字符串转节点
function create_node_from_html(html){
let template = `<div class='child'>${html}</div>`;
let tempNode = document.createElement('div');
tempNode.innerHTML = template;
return tempNode.firstChild;
}
})();