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.IsOrEmpty(url) && !string.IsOrEmpty(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

完成，达到预期的效果。