前端 PDF 导出实战：JSPDF 与 HTML2Canvas 深度解析

适用场景对比：

第二部分：JSPDF 深度解析

2.1 核心 API 详解

2.1.1 初始化与页面设置

// 创建 PDF 实例
const doc = new jsPDF({ orientation: 'p', // 方向：p-纵向，l-横向
unit: 'mm', // 单位：pt, mm, cm, in
format: 'a4', // 格式：a3, a4, a5, letter 等
compress: true, // 是否压缩
precision: 16 // 浮点数精度 });
// 页面尺寸获取
const pageWidth = doc.internal.pageSize.getWidth();
const pageHeight = doc.internal.pageSize.getHeight();
// 添加新页面
doc.addPage();
// 删除页面
doc.deletePage(2);
// 设置页面背景色
doc.setFillColor(240, 240, 240);
doc.rect(0, 0, pageWidth, pageHeight, 'F');

2.1.2 文本处理

// 基本文本设置
doc.setFont("helvetica"); // 字体
doc.setFontSize(16); // 字号
doc.setTextColor(0, 0, 0); // 颜色
doc.setFontStyle("bold"); // 样式：normal, bold, italic, bolditalic
// 添加文本
doc.text("单行文本", x, y);
doc.text("多行文本", x, y, { maxWidth: 100, // 最大宽度
align: 'left', // 对齐：left, center, right
baseline: 'top' // 基线：top, middle, bottom });
// 自动换行文本
const lines = doc.splitTextToSize(
    "这是一个很长的文本，需要自动换行显示",
    pageWidth - 40
);
doc.text(lines, 20, 30);
// 多行文本带行高
const text = "第一行\n第二行\n第三行";
doc.text(text, 20, 50, { lineHeightFactor: 1.5 });
// 旋转文本
doc.textWithRotation("旋转文本", 100, 100, 45); // 旋转 45 度

2.1.3 中文支持

// 添加中文字体
// 1. 首先需要加载字体文件
const font = 'AAEAAAAQAQAABAAAR0RFRgE...'; // Base64 编码的字体
// 2. 添加到 JSPDF
doc.addFileToVFS('chinese-normal.ttf', font);
doc.addFont('chinese-normal.ttf', 'chinese', 'normal');
// 3. 使用中文字体
doc.setFont('chinese');
doc.text('中文字体测试', 20, 20);
// 或者使用内置的亚洲字体
doc.setFont('simhei');
doc.setFontSize(16);
doc.text('使用黑体显示中文', 20, 40);

2.1.4 图片处理

// 添加图片
const imgData = 'data:image/png;base64,iVBORw0KGgo...';
doc.addImage(imgData, 'PNG', 15, 40, 180, 160);
// 完整参数
doc.addImage({ imageData: imgData,
x: 15,
y: 40,
width: 180,
height: 160,
compression: 'FAST', // 压缩等级：NONE, FAST, MEDIUM, SLOW
rotation: 0, // 旋转角度
alias: 'myImage', // 图片别名
format: 'PNG' // 格式：JPEG, PNG });
// 获取图片属性
const imgProps = doc.getImageProperties(imgData);
console.log(`图片尺寸：${imgProps.width}x${imgProps.height}`);
// 图片缩放模式
const scaleToFit = (imgWidth, imgHeight, maxWidth, maxHeight) => {
    const widthRatio = maxWidth / imgWidth;
    const heightRatio = maxHeight / imgHeight;
    const ratio = Math.min(widthRatio, heightRatio);
    return { width: imgWidth * ratio, height: imgHeight * ratio };
};

2.1.5 图形绘制

// 线条
doc.setLineWidth(0.5); // 线宽
doc.setDrawColor(0, 0, 255); // 线条颜色
doc.line(20, 20, 100, 20); // 直线
// 矩形
doc.setFillColor(255, 0, 0); // 填充色
doc.rect(20, 30, 50, 30, 'F'); // 填充矩形
doc.rect(80, 30, 50, 30, 'S'); // 描边矩形
doc.rect(140, 30, 50, 30, 'FD'); // 填充 + 描边
// 圆形/椭圆
doc.circle(60, 80, 20, 'FD'); // 圆形
doc.ellipse(120, 80, 30, 20, 'FD'); // 椭圆
// 多边形
const triangle = [[100, 120], [120, 100], [140, 120]];
doc.setFillColor(0, 255, 0);
doc.poly(triangle, 'F'); // 路径
doc.setDrawColor(128, 0, 128);
doc.setLineWidth(2);
doc.path('M 160 100 L 180 120 L 160 140 Z'); // SVG 路径语法
// 虚线
doc.setLineDashPattern([5, 5], 0); // 5 像素实线，5 像素间隔
doc.line(20, 150, 200, 150);
doc.setLineDashPattern([], 0); // 恢复实线

2.1.6 表格生成

// 使用 autoTable 插件
import jsPDF from 'jspdf';
import 'jspdf-autotable';
const doc = new jsPDF();
// 简单表格
doc.autoTable({ head: [['ID', '姓名', '年龄', '城市']], body: [
    ['1', '张三', '28', '北京'],
    ['2', '李四', '32', '上海'],
    ['3', '王五', '25', '广州']
], startY: 20,
theme: 'grid', // 主题：striped, grid, plain
styles: { fontSize: 10, cellPadding: 3, overflow: 'linebreak' },
headStyles: { fillColor: [22, 160, 133], textColor: 255, fontStyle: 'bold' },
columnStyles: {
    0: { cellWidth: 20 }, // 第一列宽度
    1: { cellWidth: 40 }
},
margin: { top: 20 },
didDrawPage: function(data) { // 每页绘制的回调
    doc.setFontSize(10);
    doc.text(`第 ${data.pageNumber} 页`, data.settings.margin.left, doc.internal.pageSize.height - 10);
}
});
// 多页表格
const largeData = [];
for (let i = 0; i < 100; i++) {
    largeData.push([i + 1, `用户${i}`, Math.floor(Math.random() * 50 + 18), '城市']);
}
doc.autoTable({ head: [['ID', '姓名', '年龄', '城市']], body: largeData,
startY: 20,
pageBreak: 'auto', // 自动分页
rowPageBreak: 'avoid', // 避免行内分页
showHead: 'everyPage' // 每页都显示表头 });

2.2 高级功能

2.2.1 页码和页眉页脚

function addHeaderFooter(doc, totalPages) {
    const pageWidth = doc.internal.pageSize.getWidth();
    const pageHeight = doc.internal.pageSize.getHeight();
    // 页眉
    doc.setFontSize(10);
    doc.setTextColor(100, 100, 100);
    doc.text('公司名称', 20, 15);
    doc.text(new Date().toLocaleDateString(), pageWidth - 20, 15, { align: 'right' });
    // 页脚
    doc.setFontSize(9);
    doc.text(`第 ${doc.internal.getCurrentPageInfo().pageNumber} 页 / 共 ${totalPages} 页`, pageWidth / 2, pageHeight - 10, { align: 'center' });
    // 页脚线
    doc.setDrawColor(200, 200, 200);
    doc.line(20, pageHeight - 15, pageWidth - 20, pageHeight - 15);
}
// 在每页绘制时调用
const totalPages = 5;
for (let i = 1; i <= totalPages; i++) {
    if (i > 1) doc.addPage();
    addHeaderFooter(doc, totalPages);
    // 添加内容...
}

2.2.2 水印功能

function addWatermark(doc, text) {
    const pageWidth = doc.internal.pageSize.getWidth();
    const pageHeight = doc.internal.pageSize.getHeight();
    // 保存当前状态
    doc.saveGraphicsState();
    // 设置水印样式
    doc.setFontSize(40);
    doc.setTextColor(200, 200, 200, 0.3); // 半透明灰色
    doc.setFont('helvetica', 'bold');
    // 计算文本宽度
    const textWidth = doc.getStringUnitWidth(text) * doc.internal.getFontSize() / doc.internal.scaleFactor;
    // 旋转和重复水印
    const angle = -45 * Math.PI / 180;
    const spacing = 150;
    doc.saveGraphicsState();
    for (let x = -pageWidth; x < pageWidth * 2; x += spacing) {
        for (let y = -pageHeight; y < pageHeight * 2; y += spacing) {
            doc.saveGraphicsState();
            doc.translate(x, y);
            doc.rotate(angle, { origin: [0, 0] });
            doc.text(text, 0, 0);
            doc.restoreGraphicsState();
        }
    }
    doc.restoreGraphicsState();
}
// 使用水印
const doc = new jsPDF();
doc.text('文档内容', 20, 20);
addWatermark(doc, '机密文件');

2.2.3 链接和书签

// 内部链接
doc.textWithLink('点击跳转到第 2 页', 20, 20, { pageNumber: 2 });
// 外部链接
doc.textWithLink('访问官网', 20, 40, { url: 'https://example.com' });
// 邮件链接
doc.textWithLink('发送邮件', 20, 60, { url: 'mailto:[email protected]' });
// 添加书签
doc.outline.add(null, "封面", 1);
doc.outline.add(null, "第一章", 2);
doc.outline.add(1, "1.1 简介", 3); // 子书签
// 可点击目录
const tocY = 30;
const chapters = [
    { title: "第一章 简介", page: 1 },
    { title: "第二章 基础", page: 3 },
    { title: "第三章 高级", page: 5 }
];
chapters.forEach((chapter, i) => {
    doc.text(chapter.title, 20, tocY + i * 10);
    doc.textWithLink(`第${chapter.page}页`, 150, tocY + i * 10, { pageNumber: chapter.page });
});

第三部分：HTML2Canvas 深度解析

3.1 核心原理与架构

HTML2Canvas 的工作原理相当复杂，它本质上是一个简化的浏览器渲染引擎。让我们深入了解它的工作流程：

3.1.2 核心组件

// HTML2Canvas 内部结构示意
class HTML2CanvasRenderer {
    constructor(element, options) {
        this.element = element;
        this.options = options;
        this.canvas = document.createElement('canvas');
        this.ctx = this.canvas.getContext('2d');
    }
    async render() {
        // 1. 解析 DOM 树
        const root = this.parseDOM(this.element);
        // 2. 计算样式
        this.calculateStyles(root);
        // 3. 创建渲染树
        const renderTree = this.createRenderTree(root);
        // 4. 布局计算
        this.calculateLayout(renderTree);
        // 5. 绘制
        await this.draw(renderTree);
        return this.canvas;
    }
    // ... 其他方法
}

3.2 配置参数详解

const options = {
    // 基本配置
    allowTaint: false, // 是否允许污染 canvas
    useCORS: true, // 是否使用 CORS 加载图片
    backgroundColor: '#ffffff', // 背景色
    scale: 2, // 缩放比例（设备像素比）
    width: null, // 自定义宽度
    height: null, // 自定义高度
    // 日志和调试
    logging: true, // 启用日志
    onclone: null, // DOM 克隆后的回调
    // 图像配置
    imageTimeout: 15000, // 图片加载超时 (ms)
    proxy: null, // 代理服务器 URL
    removeContainer: true, // 是否移除临时容器
    // 高级配置
    foreignObjectRendering: false, // 使用 foreignObject（SVG）
    ignoreElements: (element) => false, // 忽略特定元素
    onrendered: null, // 渲染完成回调
    // 性能配置
    async: true, // 异步渲染
    cacheBust: false, // 缓存破坏
    letterRendering: false, // 文字渲染优化
    // Canvas 配置
    canvas: null, // 使用现有 canvas
    x: 0, // 水平偏移
    y: 0, // 垂直偏移
    scrollX: 0, // 水平滚动
    scrollY: 0, // 垂直滚动
    windowWidth: window.innerWidth, // 窗口宽度
    windowHeight: window.innerHeight // 窗口高度
};

第四部分：JSPDF 与 HTML2Canvas 集成实战

4.1 基础集成方案

// 基础集成函数
async function exportToPDF(elementId, fileName = 'document.pdf', options = {}) {
    // 默认配置
    const defaultOptions = {
        pdf: { orientation: 'p', unit: 'mm', format: 'a4', compress: true },
        html2canvas: { scale: 2, useCORS: true, logging: false },
        margin: { top: 15, right: 15, bottom: 15, left: 15 }
    };
    // 合并配置
    const config = {
        pdf: { ...defaultOptions.pdf, ...options.pdf },
        html2canvas: { ...defaultOptions.html2canvas, ...options.html2canvas },
        margin: { ...defaultOptions.margin, ...options.margin }
    };
    try {
        // 1. 获取目标元素
        const element = document.getElementById(elementId);
        if (!element) {
            throw new Error(`元素 #${elementId} 未找到`);
        }
        // 2. 使用 html2canvas 生成 canvas
        console.log('开始生成 canvas...');
        const canvas = await html2canvas(element, config.html2canvas);
        // 3. 获取图片数据
        const imgData = canvas.toDataURL('image/png', 1.0);
        const imgProps = { width: canvas.width, height: canvas.height };
        // 4. 计算 PDF 尺寸
        const pdfWidth = config.pdf.format === 'a4' ? 210 : 297; // A4 宽度 210mm
        const pdfHeight = config.pdf.format === 'a4' ? 297 : 210; // A4 高度 297mm
        // 可用宽度 = PDF 宽度 - 左右边距
        const usableWidth = pdfWidth - config.margin.left - config.margin.right;
        // 5. 计算缩放比例
        const pixelsPerMM = imgProps.width / usableWidth;
        const scale = usableWidth / imgProps.width;
        const imgHeightMM = imgProps.height * scale;
        // 6. 创建 PDF
        console.log('创建 PDF 文档...');
        const doc = new jsPDF(config.pdf);
        // 7. 处理分页
        const pageHeight = pdfHeight - config.margin.top - config.margin.bottom;
        let position = 0;
        if (imgHeightMM <= pageHeight) {
            // 一页能放下
            doc.addImage(imgData, 'PNG', config.margin.left, config.margin.top, usableWidth, imgHeightMM);
        } else {
            // 需要分页
            while (position < imgHeightMM) {
                if (position > 0) {
                    doc.addPage();
                }
                doc.addImage(imgData, 'PNG', config.margin.left, config.margin.top - position, usableWidth, imgHeightMM);
                position += pageHeight;
            }
        }
        // 8. 保存 PDF
        doc.save(fileName);
        console.log('PDF 导出完成');
        return doc;
    } catch (error) {
        console.error('导出 PDF 失败:', error);
        throw error;
    }
}
// 使用示例
document.getElementById('export-btn').addEventListener('click', async () => {
    try {
        await exportToPDF('content', '报告.pdf', {
            pdf: { format: 'a4', orientation: 'portrait' },
            html2canvas: { scale: 3, // 更高清
                backgroundColor: '#ffffff'
            },
            margin: { top: 20, right: 20, bottom: 20, left: 20 }
        });
    } catch (error) {
        alert('导出失败：' + error.message);
    }
});

4.2 高级集成：智能分页与表格保护

class SmartPDFExporter {
    constructor(options = {}) {
        this.options = this.mergeOptions(options);
        this.pageBreaks = [];
    }
    mergeOptions(options) {
        const defaults = {
            elementId: null,
            fileName: 'export.pdf',
            pdf: { orientation: 'p', unit: 'mm', format: 'a4' },
            html2canvas: { scale: 2, logging: false, useCORS: true },
            styling: { tableProtection: true, keepTogetherClass: 'keep-together', avoidBreakClass: 'avoid-break' },
            margins: { top: 15, right: 15, bottom: 15, left: 15 },
            features: { pageNumbers: true, header: true, footer: true, watermark: false }
        };
        return this.deepMerge(defaults, options);
    }
    deepMerge(target, source) {
        for (const key in source) {
            if (source[key] && typeof source[key] === 'object' && !Array.isArray(source[key])) {
                if (!target[key]) target[key] = {};
                this.deepMerge(target[key], source[key]);
            } else {
                target[key] = source[key];
            }
        }
        return target;
    }
    async export() {
        try {
            // 1. 验证和准备
            this.validateInput();
            // 2. 应用保护样式
            if (this.options.styling.tableProtection) {
                this.applyProtectionStyles();
            }
            // 3. 分析 DOM 结构
            const analysis = await this.analyzeDOM();
            // 4. 计算分页点
            this.calculatePageBreaks(analysis);
            // 5. 生成 canvas
            const canvas = await this.generateCanvas();
            // 6. 创建 PDF
            const pdf = await this.generatePDF(canvas, analysis);
            // 7. 保存
            pdf.save(this.options.fileName);
            return { success: true, pdf };
        } catch (error) {
            console.error('导出失败:', error);
            throw error;
        }
    }
    validateInput() {
        if (!this.options.elementId) {
            throw new Error('elementId 必须提供');
        }
        const element = document.getElementById(this.options.elementId);
        if (!element) {
            throw new Error(`元素 #${this.options.elementId} 未找到`);
        }
        this.element = element;
    }
    applyProtectionStyles() {
        const style = document.createElement('style');
        style.textContent = `
.${this.options.styling.keepTogetherClass} { page-break-inside: avoid !important; break-inside: avoid !important; }
.${this.options.styling.avoidBreakClass} { page-break-before: avoid !important; break-before: avoid !important; }
table { page-break-inside: avoid !important; break-inside: avoid !important; border-collapse: collapse !important; }
tr { page-break-inside: avoid !important; break-inside: avoid !important; }
`;
        // 移除可能存在的旧样式
        const oldStyles = this.element.querySelectorAll('style[data-pdf-protection]');
        oldStyles.forEach(s => s.remove());
        style.setAttribute('data-pdf-protection', 'true');
        this.element.appendChild(style);
        // 为表格添加保护类
        const tables = this.element.querySelectorAll('table');
        tables.forEach(table => {
            table.classList.add(this.options.styling.keepTogetherClass);
        });
        // 为重要元素添加避免分页类
        const importantElements = this.element.querySelectorAll('h1, h2, .important');
        importantElements.forEach(el => {
            el.classList.add(this.options.styling.avoidBreakClass);
        });
    }
    async analyzeDOM() {
        const tables = this.element.querySelectorAll('table');
        const importantElements = this.element.querySelectorAll(`.${this.options.styling.keepTogetherClass}`);
        const elementRect = this.element.getBoundingClientRect();
        const analysis = {
            tables: [],
            importantElements: [],
            containerHeight: this.element.offsetHeight,
            containerWidth: this.element.offsetWidth
        };
        // 分析表格
        tables.forEach((table, index) => {
            const rect = table.getBoundingClientRect();
            analysis.tables.push({
                index,
                element: table,
                top: rect.top - elementRect.top,
                bottom: rect.bottom - elementRect.top,
                height: rect.height,
                rowCount: table.querySelectorAll('tr').length,
                canBreak: !table.classList.contains(this.options.styling.keepTogetherClass)
            });
        });
        // 分析重要元素
        importantElements.forEach((el, index) => {
            if (el.tagName !== 'TABLE') { // 表格已经分析过了
                const rect = el.getBoundingClientRect();
                analysis.importantElements.push({
                    index,
                    element: el,
                    top: rect.top - elementRect.top,
                    bottom: rect.bottom - elementRect.top,
                    height: rect.height,
                    tagName: el.tagName
                });
            }
        });
        // 按位置排序
        analysis.tables.sort((a, b) => a.top - b.top);
        analysis.importantElements.sort((a, b) => a.top - b.top);
        return analysis;
    }
    calculatePageBreaks(analysis) {
        const pdf = new jsPDF(this.options.pdf);
        const pdfWidth = pdf.internal.pageSize.getWidth();
        const pdfHeight = pdf.internal.pageSize.getHeight();
        const usableWidth = pdfWidth - this.options.margins.left - this.options.margins.right;
        const usableHeight = pdfHeight - this.options.margins.top - this.options.margins.bottom;
        // 像素到毫米的转换比例
        const pxToMM = usableWidth / analysis.containerWidth;
        const breaks = [];
        let currentPageHeightMM = 0;
        // 处理所有需要保护的元素
        const allElements = [...analysis.tables, ...analysis.importantElements].sort((a, b) => a.top - b.top);
        allElements.forEach((element, index) => {
            const elementHeightMM = element.height * pxToMM;
            // 检查是否放得下
            if (currentPageHeightMM + elementHeightMM > usableHeight && currentPageHeightMM > 0) {
                // 放不下，需要分页
                if (index > 0) {
                    const prevElement = allElements[index - 1];
                    // 在元素前分页
                    breaks.push({ type: 'before', element: element, position: element.top, reason: `${element.tagName || 'table'} 无法放入当前页` });
                    currentPageHeightMM = elementHeightMM;
                }
            } else {
                // 放得下
                currentPageHeightMM += elementHeightMM;
            }
        });
        this.pageBreaks = breaks;
        console.log('计算出的分页点:', this.pageBreaks);
    }
    async generateCanvas() {
        // 固定尺寸，防止渲染时变化
        const originalStyle = {
            width: this.element.style.width,
            height: this.element.style.height,
            position: this.element.style.position
        };
        this.element.style.width = `${this.element.offsetWidth}px`;
        this.element.style.height = `${this.element.offsetHeight}px`;
        this.element.style.position = 'relative';
        try {
            const canvas = await html2canvas(this.element, this.options.html2canvas);
            return canvas;
        } finally {
            // 恢复原始样式
            Object.assign(this.element.style, originalStyle);
        }
    }
    async generatePDF(canvas, analysis) {
        const pdf = new jsPDF(this.options.pdf);
        const pdfWidth = pdf.internal.pageSize.getWidth();
        const pdfHeight = pdf.internal.pageSize.getHeight();
        const usableWidth = pdfWidth - this.options.margins.left - this.options.margins.right;
        const usableHeight = pdfHeight - this.options.margins.top - this.options.margins.bottom;
        // 计算缩放
        const scale = usableWidth / canvas.width;
        const totalHeightMM = canvas.height * scale;
        // 如果有分页点，使用智能分页
        if (this.pageBreaks.length > 0) {
            await this.generatePDFWithBreaks(pdf, canvas, scale, usableWidth, usableHeight);
        } else {
            // 无分页点，使用简单分页
            await this.generatePDFSimple(pdf, canvas, scale, usableWidth, usableHeight);
        }
        // 添加页眉页脚
        if (this.options.features.header || this.options.features.footer) {
            this.addHeaderFooter(pdf, this.pageBreaks.length + 1);
        }
        // 添加水印
        if (this.options.features.watermark) {
            this.addWatermark(pdf);
        }
        return pdf;
    }
    async generatePDFWithBreaks(pdf, canvas, scale, usableWidth, usableHeight) {
        const imgData = canvas.toDataURL('image/png', 1.0);
        // 转换分页点为 canvas 像素位置
        const breakPoints = this.pageBreaks.map(breakInfo => breakInfo.position);
        breakPoints.sort((a, b) => a - b);
        // 确保从 0 开始，到 canvas 高度结束
        const allPoints = [0, ...breakPoints, canvas.height];
        let startY = 0;
        for (let i = 1; i < allPoints.length; i++) {
            const segmentHeight = allPoints[i] - startY;
            if (segmentHeight <= 0) continue;
            // 创建当前页的 canvas 片段
            const segmentCanvas = document.createElement('canvas');
            segmentCanvas.width = canvas.width;
            segmentCanvas.height = segmentHeight;
            const ctx = segmentCanvas.getContext('2d');
            ctx.drawImage(
                canvas,
                0, startY, canvas.width, segmentHeight,
                0, 0, canvas.width, segmentHeight
            );
            const segmentImgData = segmentCanvas.toDataURL('image/png', 1.0);
            const segmentHeightMM = segmentHeight * scale;
            // 如果不是第一页，添加新页
            if (i > 1) {
                pdf.addPage();
            }
            // 添加图片到 PDF
            pdf.addImage(
                segmentImgData, 'PNG', this.options.margins.left, this.options.margins.top, usableWidth, segmentHeightMM
            );
            startY = allPoints[i];
        }
    }
    generatePDFSimple(pdf, canvas, scale, usableWidth, usableHeight) {
        const imgData = canvas.toDataURL('image/png', 1.0);
        const totalHeightMM = canvas.height * scale;
        if (totalHeightMM <= usableHeight) {
            // 一页能放下
            pdf.addImage(
                imgData, 'PNG', this.options.margins.left, this.options.margins.top, usableWidth, totalHeightMM
            );
        } else {
            // 需要分页
            let position = 0;
            while (position < totalHeightMM) {
                if (position > 0) {
                    pdf.addPage();
                }
                pdf.addImage(
                    imgData, 'PNG', this.options.margins.left, this.options.margins.top - position, usableWidth, totalHeightMM
                );
                position += usableHeight;
            }
        }
    }
    addHeaderFooter(pdf, totalPages) {
        const pdfWidth = pdf.internal.pageSize.getWidth();
        const pdfHeight = pdf.internal.pageSize.getHeight();
        const currentPage = pdf.internal.getCurrentPageInfo().pageNumber;
        // 保存当前状态
        const originalFont = pdf.internal.getFont();
        const originalSize = pdf.internal.getFontSize();
        const originalColor = pdf.internal.getTextColor();
        // 页眉
        if (this.options.features.header) {
            pdf.setFontSize(10);
            pdf.setTextColor(100, 100, 100);
            // 左侧：标题
            pdf.text(
                this.options.fileName.replace('.pdf', ''),
                this.options.margins.left,
                this.options.margins.top - 10
            );
            // 右侧：日期
            const dateStr = new Date().toLocaleDateString();
            pdf.text(
                dateStr,
                pdfWidth - this.options.margins.right,
                this.options.margins.top - 10,
                { align: 'right' }
            );
            // 页眉线
            pdf.setDrawColor(200, 200, 200);
            pdf.line(
                this.options.margins.left,
                this.options.margins.top - 5,
                pdfWidth - this.options.margins.right,
                this.options.margins.top - 5
            );
        }
        // 页脚
        if (this.options.features.footer) {
            // 页脚线
            pdf.setDrawColor(200, 200, 200);
            pdf.line(
                this.options.margins.left,
                pdfHeight - this.options.margins.bottom + 5,
                pdfWidth - this.options.margins.right,
                pdfHeight - this.options.margins.bottom + 5
            );
            // 页码
            if (this.options.features.pageNumbers) {
                pdf.setFontSize(9);
                pdf.setTextColor(100, 100, 100);
                const pageText = `第 ${currentPage} 页 / 共 ${totalPages} 页`;
                pdf.text(
                    pageText,
                    pdfWidth / 2,
                    pdfHeight - this.options.margins.bottom + 10,
                    { align: 'center' }
                );
            }
        }
        // 恢复原始状态
        pdf.setFont(originalFont[0], originalFont[1]);
        pdf.setFontSize(originalSize);
        pdf.setTextColor(originalColor[0], originalColor[1], originalColor[2]);
    }
    addWatermark(pdf) {
        const pdfWidth = pdf.internal.pageSize.getWidth();
        const pdfHeight = pdf.internal.pageSize.getHeight();
        // 保存状态
        pdf.saveGraphicsState();
        // 设置水印样式
        pdf.setFontSize(40);
        pdf.setTextColor(200, 200, 200, 0.1);
        pdf.setFont('helvetica', 'bold');
        // 旋转和重复
        const angle = -45 * Math.PI / 180;
        const text = this.options.features.watermark.text || 'CONFIDENTIAL';
        for (let x = -pdfWidth; x < pdfWidth * 2; x += 150) {
            for (let y = -pdfHeight; y < pdfHeight * 2; y += 150) {
                pdf.saveGraphicsState();
                pdf.translate(x, y);
                pdf.rotate(angle, { origin: [0, 0] });
                pdf.text(text, 0, 0);
                pdf.restoreGraphicsState();
            }
        }
        pdf.restoreGraphicsState();
    }
}
// 使用示例
const exporter = new SmartPDFExporter({
    elementId: 'report-content',
    fileName: '智能报告.pdf',
    pdf: { format: 'a4', orientation: 'portrait' },
    html2canvas: { scale: 2, useCORS: true, backgroundColor: '#ffffff' },
    features: {
        pageNumbers: true,
        header: true,
        footer: true,
        watermark: { text: '公司机密', enabled: true }
    },
    styling: { tableProtection: true, keepTogetherClass: 'pdf-keep-together' }
});
// 触发导出
document.getElementById('smart-export').addEventListener('click', async () => {
    try {
        await exporter.export();
        alert('导出成功！');
    } catch (error) {
        alert('导出失败：' + error.message);
    }
});

4.3 响应式与移动端适配

class ResponsivePDFExporter {
    constructor(options = {}) {
        this.options = {
            breakpoints: {
                mobile: 768,
                tablet: 1024,
                desktop: 1200
            },
            scaling: {
                mobile: 1,
                tablet: 1.5,
                desktop: 2
            },
            ...options
        };
    }
    detectDeviceType() {
        const width = window.innerWidth;
        if (width < this.options.breakpoints.mobile) {
            return 'mobile';
        } else if (width < this.options.breakpoints.tablet) {
            return 'tablet';
        } else {
            return 'desktop';
        }
    }
    async exportResponsive(elementId, fileName) {
        const deviceType = this.detectDeviceType();
        const scale = this.options.scaling[deviceType] || 1.5;
        console.log(`设备类型：${deviceType}, 使用缩放：${scale}`);
        // 调整元素样式以适应 PDF
        const element = document.getElementById(elementId);
        const originalStyles = this.backupStyles(element);
        try {
            // 应用响应式样式
            this.applyResponsiveStyles(element, deviceType);
            // 生成 PDF
            const canvas = await html2canvas(element, {
                scale,
                useCORS: true,
                backgroundColor: '#ffffff'
            });
            const pdf = new jsPDF({ orientation: 'p', unit: 'mm', format: 'a4' });
            const pdfWidth = pdf.internal.pageSize.getWidth();
            const imgWidth = canvas.width;
            const imgHeight = canvas.height;
            // 计算缩放比例
            const margin = 10;
            const usableWidth = pdfWidth - 2 * margin;
            const scaleFactor = usableWidth / imgWidth;
            pdf.addImage(
                canvas.toDataURL('image/png', 1.0),
                'PNG',
                margin,
                margin,
                usableWidth,
                imgHeight * scaleFactor
            );
            pdf.save(fileName);
        } finally {
            // 恢复原始样式
            this.restoreStyles(element, originalStyles);
        }
    }
    backupStyles(element) {
        return {
            width: element.style.width,
            height: element.style.height,
            fontSize: element.style.fontSize,
            padding: element.style.padding,
            margin: element.style.margin,
            display: element.style.display
        };
    }
    applyResponsiveStyles(element, deviceType) {
        // 根据设备类型应用不同的样式
        const styles = {
            mobile: { width: '100%', fontSize: '12px', padding: '10px', margin: '0', display: 'block' },
            tablet: { width: '90%', fontSize: '13px', padding: '15px', margin: '0 auto', display: 'block' },
            desktop: { width: '80%', fontSize: '14px', padding: '20px', margin: '0 auto', display: 'block' }
        };
        const deviceStyles = styles[deviceType] || styles.desktop;
        Object.assign(element.style, deviceStyles);
        // 特别处理表格
        const tables = element.querySelectorAll('table');
        tables.forEach(table => {
            if (deviceType === 'mobile') {
                table.style.fontSize = '10px';
                table.style.width = '100%';
            }
        });
    }
    restoreStyles(element, originalStyles) {
        Object.assign(element.style, originalStyles);
    }
}
// 使用响应式导出
const responsiveExporter = new ResponsivePDFExporter();
// 响应式导出按钮
document.getElementById('responsive-export').addEventListener('click', () => {
    responsiveExporter.exportResponsive('content', '响应式报告.pdf');
});