C# 将 HTML 转换为图片或 PDF

首先是把 HTML 转换为图片。

public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        WebBrowser webBrowser = null;        public void ConvertToImg()        {            webBrowser = new WebBrowser();            //是否显式滚动条            webBrowser.ScrollBarsEnabled = false;            //加载HTML页面的地址            webBrowser.Navigate("http://www.baidu.com");                        //页面加载完成执行事件            webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);        }        private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作        {            //获取解析后HTML的大小            System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;            int width = rectangle.Width;            int height = rectangle.Height;            //设置解析后HTML的可视区域            webBrowser.Width = width;            webBrowser.Height = height;            Bitmap bitmap = new System.Drawing.Bitmap(width, height);            webBrowser.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, width, height));            //设置图片文件保存路径和图片格式，格式可以自定义            string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png";            bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);        }        private void button1_Click(object sender, EventArgs e)        {            ConvertToImg();        }    }

上面这种方法是解析指定URL地址的HTML，然后转换为图片。当然，也可以直接写一些HTML标签。如下：

public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        WebBrowser webBrowser = null;        public void ConvertToImg()        {            string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";            webBrowser = new WebBrowser();            //是否显式滚动条            webBrowser.ScrollBarsEnabled = false;            //加载 html            webBrowser.DocumentText = html;                        //页面加载完成执行事件            webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);        }        private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作        {            //获取解析后HTML的大小            System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;            int width = rectangle.Width;            int height = rectangle.Height;            //设置解析后HTML的可视区域            webBrowser.Width = width;            webBrowser.Height = height;            Bitmap bitmap = new System.Drawing.Bitmap(width, height);            webBrowser.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, width, height));            //设置图片文件保存路径和图片格式，格式可以自定义            string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png";            bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);        }        private void button1_Click(object sender, EventArgs e)        {            ConvertToImg();        }    }

 

然后把图片转换为PDF，这里需要用到 iTextSharp.dll 这个组件。

public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        WebBrowser webBrowser = null;        public void ConvertToImg()        {            string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";            webBrowser = new WebBrowser();            //是否显式滚动条            webBrowser.ScrollBarsEnabled = false;            //加载 html            webBrowser.DocumentText = html;                        //页面加载完成执行事件            webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);        }        private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作        {            //获取解析后HTML的大小            System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;            int width = rectangle.Width;            int height = rectangle.Height;            //设置解析后HTML的可视区域            webBrowser.Width = width;            webBrowser.Height = height;            Bitmap bitmap = new System.Drawing.Bitmap(width, height);            webBrowser.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, width, height));            //设置图片文件保存路径和图片格式，格式可以自定义            string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png";            bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);            //创建PDF            FileStream fileStream = new FileStream(AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".pdf", FileMode.Create);            byte[] result = CreatePDF(bitmap, width, height);            fileStream.Write(result, 0, result.Length);            fileStream.Close();            fileStream.Dispose();        }        private void button1_Click(object sender, EventArgs e)        {            ConvertToImg();        }        public byte[] CreatePDF(Bitmap bitmap, int width, int height)        {            using (MemoryStream ms = new MemoryStream())            {                Document doc = new Document(new iTextSharp.text.Rectangle(0, 0, width, height), 3, 3, 3, 3);    // 左右上下                PdfWriter writer = PdfWriter.GetInstance(doc, ms);                writer.CloseStream = false;                doc.Open();                iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(bitmap, System.Drawing.Imaging.ImageFormat.Png);                img.ScalePercent(100);      // 放缩比例                doc.Add(img);       // 添加图片对像                doc.Close();                return ms.ToArray();            }        }    }

不过这种生成图片之后再转成PDF，会造成像素的丢失，所以看起来要比图片模糊一点。

 

还有一种办法就是直接生成PDF，这里需要安装 ABCpdf。不过，这个是收费的。。。

public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        public void ConvertToPDF()        {            string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";            //创建一个Doc对象            Doc doc = new Doc();            //Rect默认是文档整个页面大小,这里的Inset表示将Rect左右留出15的空白,上下留出20的空白            doc.Rect.Inset(15, 20);            //直接设置html            int docID = doc.AddHtml(html);            //设置URL            //int docID = doc.AddImageUrl("http://www.baidu.com");            //设置字体            doc.AddFont("Arial");            while (true)            {                //判断是否还有内容                if (!doc.Chainable(docID))                {                    break;                }                //如果还有内容就添加一页                doc.Page = doc.AddPage();                //根据ID添加内容并返回页面上该内容对应的新ID                docID = doc.AddImageToChain(docID);            }            string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".pdf";            doc.Save(filePath);            doc.Clear();            doc.Dispose();        }        private void button1_Click(object sender, EventArgs e)        {            ConvertToPDF();        }            }