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C#实现网页加载后将页面截取成长图片


背景

最近再做一个需求,需要对网页生成预览图,如下图

 

C#实现网页加载后将页面截取成长图片

 

 

 

但是网页千千万,总不能一个个打开,截图吧;于是想着能不能使用代码来实现网页的截图。其实要实现这个功能,无非就是要么实现一个仿真浏览器,要么调用系统浏览器,再进行截图操作。

代码实现

1、启用线程Thread

 void startPrintScreen(ScreenShotParam requestParam)         {             Thread thread = new Thread(new ParameterizedThreadStart(do_PrintScreen));             thread.SetApartmentState(ApartmentState.STA);             thread.Start(requestParam);             if (requestParam.Wait)             {                 thread.Join();                 FileInfo result = new FileInfo(requestParam.SavePath);                 long minSize = 1 * 1024;// 太小可能是空白圖,重抓                 int maxRepeat = 2;                                 while ((!result.Exists || result.Length <= minSize) && maxRepeat > 0)                 {                     thread = new Thread(new ParameterizedThreadStart(do_PrintScreen));                     thread.SetApartmentState(ApartmentState.STA);                     thread.Start(requestParam);                     thread.Join();                     maxRepeat--;                 }             }         }

2、模拟浏览器WebBrowser

void do_PrintScreen(object param)         {             try             {                 ScreenShotParam screenShotParam = (ScreenShotParam)param;                 string requestUrl = screenShotParam.Url;                 string savePath = screenShotParam.SavePath;                 WebBrowser wb = new WebBrowser();                 wb.ScrollBarsEnabled = false;                 wb.ScriptErrorsSuppressed = true;                 wb.Navigate(requestUrl);                 logger.Debug("wb.Navigate");                 DateTime startTime = DateTime.Now;                 TimeSpan waitTime = new TimeSpan(0, 0, 0, 10, 0);// 10 second                 while (wb.ReadyState != WebBrowserReadyState.Complete)                 {                     Application.DoEvents();                     if (DateTime.Now - startTime > waitTime)                     {                         wb.Dispose();                         logger.Debug("wb.Dispose() timeout");                         return;                     }                 }                  wb.Width = screenShotParam.Left + screenShotParam.Width + screenShotParam.Left; // wb.Document.Body.ScrollRectangle.Width (避掉左右側的邊線);                 wb.Height = screenShotParam.Top + screenShotParam.Height; // wb.Document.Body.ScrollRectangle.Height;                 wb.ScrollBarsEnabled = false;                 wb.Document.Body.Style = "overflow:hidden";//hide scroll bar                 var doc = (wb.Document.DomDocument) as mshtml.IHTMLDocument2;                 var style = doc.createStyleSheet("", 0);                 style.cssText = @"img { border-style: none; }";                  Bitmap bitmap = new Bitmap(wb.Width, wb.Height);                 wb.DrawToBitmap(bitmap, new Rectangle(0, 0, wb.Width, wb.Height));                 wb.Dispose();                 logger.Debug("wb.Dispose()");                  bitmap = CutImage(bitmap, new Rectangle(screenShotParam.Left, screenShotParam.Top, screenShotParam.Width, screenShotParam.Height));                 bool needResize = screenShotParam.Width > screenShotParam.ResizeMaxWidth || screenShotParam.Height > screenShotParam.ResizeMaxWidth;                 if (needResize)                 {                     double greaterLength = bitmap.Width > bitmap.Height ? bitmap.Width : bitmap.Height;                     double ratio = screenShotParam.ResizeMaxWidth / greaterLength;                     bitmap = Resize(bitmap, ratio);                 }                  bitmap.Save(savePath, System.Drawing.Imaging.ImageFormat.Gif);                 bitmap.Dispose();                 logger.Debug("bitmap.Dispose();");                 logger.Debug("finish");              }             catch (Exception ex)             {                 logger.Info($"exception: {ex.Message}");             }         }

3、截图操作

private static Bitmap CutImage(Bitmap source, Rectangle section)         {             // An empty bitmap which will hold the cropped image             Bitmap bmp = new Bitmap(section.Width, section.Height);             //using (Bitmap bmp = new Bitmap(section.Width, section.Height))             {                 Graphics g = Graphics.FromImage(bmp);                  // Draw the given area (section) of the source image                 // at location 0,0 on the empty bitmap (bmp)                 g.DrawImage(source, 0, 0, section, GraphicsUnit.Pixel);                  return bmp;             }         }          private static Bitmap Resize(Bitmap originImage, Double times)         {             int width = Convert.ToInt32(originImage.Width * times);             int height = Convert.ToInt32(originImage.Height * times);              return ResizeProcess(originImage, originImage.Width, originImage.Height, width, height);         }

完整代码

 public static string ScreenShotAndSaveAmazonS3(string account, string locale, Guid rule_ID, Guid template_ID)         {                        //新的Template             var url = string.Format("https://xxxx/public/previewtemplate?showTemplateName=0&locale={0}&inputTemplateId={1}&inputThemeId=&Account={2}",                 locale,                 template_ID,                 account                 );                           var tempPath = Tools.GetAppSetting("TempPath");              //路徑準備             var userPath = AmazonS3.GetS3UploadDirectory(account, locale, AmazonS3.S3SubFolder.Template);             var fileName = string.Format("{0}.gif", template_ID);             var fullFilePath = Path.Combine(userPath.LocalDirectoryPath, fileName);             logger.Debug("userPath: {0}, fileName: {1}, fullFilePath: {2}, url:{3}", userPath, fileName, fullFilePath, url);               //開始截圖,並暫存在本機             var screen = new Screen();             screen.ScreenShot(url, fullFilePath);              //將截圖,儲存到 Amazon S3             //var previewImageUrl = AmazonS3.UploadFile(fullFilePath, userPath.RemotePath + fileName);              return string.Empty;         }

using System; using System.Collections.Generic; using System.Drawing; using System.IO; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks; using System.Windows.Forms;  namespace PrintScreen.Common {     public class Screen     {         protected static NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();          public void ScreenShot(string url, string path             , int width = 400, int height = 300             , int left = 50, int top = 50             , int resizeMaxWidth = 200, int wait = 1)         {             if (!string.IsNullOrEmpty(url) && !string.IsNullOrEmpty(path))             {                 ScreenShotParam requestParam = new ScreenShotParam                 {                     Url = url,                     SavePath = path,                     Width = width,                     Height = height,                     Left = left,                     Top = top,                     ResizeMaxWidth = resizeMaxWidth,                     Wait = wait != 0                 };                 startPrintScreen(requestParam);             }         }          void startPrintScreen(ScreenShotParam requestParam)         {             Thread thread = new Thread(new ParameterizedThreadStart(do_PrintScreen));             thread.SetApartmentState(ApartmentState.STA);             thread.Start(requestParam);             if (requestParam.Wait)             {                 thread.Join();                 FileInfo result = new FileInfo(requestParam.SavePath);                 long minSize = 1 * 1024;// 太小可能是空白圖,重抓                 int maxRepeat = 2;                                 while ((!result.Exists || result.Length <= minSize) && maxRepeat > 0)                 {                     thread = new Thread(new ParameterizedThreadStart(do_PrintScreen));                     thread.SetApartmentState(ApartmentState.STA);                     thread.Start(requestParam);                     thread.Join();                     maxRepeat--;                 }             }         }          void do_PrintScreen(object param)         {             try             {                 ScreenShotParam screenShotParam = (ScreenShotParam)param;                 string requestUrl = screenShotParam.Url;                 string savePath = screenShotParam.SavePath;                 WebBrowser wb = new WebBrowser();                 wb.ScrollBarsEnabled = false;                 wb.ScriptErrorsSuppressed = true;                 wb.Navigate(requestUrl);                 logger.Debug("wb.Navigate");                 DateTime startTime = DateTime.Now;                 TimeSpan waitTime = new TimeSpan(0, 0, 0, 10, 0);// 10 second                 while (wb.ReadyState != WebBrowserReadyState.Complete)                 {                     Application.DoEvents();                     if (DateTime.Now - startTime > waitTime)                     {                         wb.Dispose();                         logger.Debug("wb.Dispose() timeout");                         return;                     }                 }                  wb.Width = screenShotParam.Left + screenShotParam.Width + screenShotParam.Left; // wb.Document.Body.ScrollRectangle.Width (避掉左右側的邊線);                 wb.Height = screenShotParam.Top + screenShotParam.Height; // wb.Document.Body.ScrollRectangle.Height;                 wb.ScrollBarsEnabled = false;                 wb.Document.Body.Style = "overflow:hidden";//hide scroll bar                 var doc = (wb.Document.DomDocument) as mshtml.IHTMLDocument2;                 var style = doc.createStyleSheet("", 0);                 style.cssText = @"img { border-style: none; }";                  Bitmap bitmap = new Bitmap(wb.Width, wb.Height);                 wb.DrawToBitmap(bitmap, new Rectangle(0, 0, wb.Width, wb.Height));                 wb.Dispose();                 logger.Debug("wb.Dispose()");                  bitmap = CutImage(bitmap, new Rectangle(screenShotParam.Left, screenShotParam.Top, screenShotParam.Width, screenShotParam.Height));                 bool needResize = screenShotParam.Width > screenShotParam.ResizeMaxWidth || screenShotParam.Height > screenShotParam.ResizeMaxWidth;                 if (needResize)                 {                     double greaterLength = bitmap.Width > bitmap.Height ? bitmap.Width : bitmap.Height;                     double ratio = screenShotParam.ResizeMaxWidth / greaterLength;                     bitmap = Resize(bitmap, ratio);                 }                  bitmap.Save(savePath, System.Drawing.Imaging.ImageFormat.Gif);                 bitmap.Dispose();                 logger.Debug("bitmap.Dispose();");                 logger.Debug("finish");              }             catch (Exception ex)             {                 logger.Info($"exception: {ex.Message}");             }         }          private static Bitmap CutImage(Bitmap source, Rectangle section)         {             // An empty bitmap which will hold the cropped image             Bitmap bmp = new Bitmap(section.Width, section.Height);             //using (Bitmap bmp = new Bitmap(section.Width, section.Height))             {                 Graphics g = Graphics.FromImage(bmp);                  // Draw the given area (section) of the source image                 // at location 0,0 on the empty bitmap (bmp)                 g.DrawImage(source, 0, 0, section, GraphicsUnit.Pixel);                  return bmp;             }         }          private static Bitmap Resize(Bitmap originImage, Double times)         {             int width = Convert.ToInt32(originImage.Width * times);             int height = Convert.ToInt32(originImage.Height * times);              return ResizeProcess(originImage, originImage.Width, originImage.Height, width, height);         }          private static Bitmap ResizeProcess(Bitmap originImage, int oriwidth, int oriheight, int width, int height)         {             Bitmap resizedbitmap = new Bitmap(width, height);             //using (Bitmap resizedbitmap = new Bitmap(width, height))             {                 Graphics g = Graphics.FromImage(resizedbitmap);                 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;                 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;                 g.Clear(Color.Transparent);                 g.DrawImage(originImage, new Rectangle(0, 0, width, height), new Rectangle(0, 0, oriwidth, oriheight), GraphicsUnit.Pixel);                 return resizedbitmap;             }         }      }      class ScreenShotParam     {         public string Url { get; set; }         public string SavePath { get; set; }         public int Width { get; set; }         public int Height { get; set; }         public int Left { get; set; }         public int Top { get; set; }         /// <summary>         /// 長邊縮到指定長度         /// </summary>         public int ResizeMaxWidth { get; set; }         public bool Wait { get; set; }     }  }

效果

C#实现网页加载后将页面截取成长图片

 

 完成,达到预期的效果。

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