背景
最近再做一个需求，需要对网页生成预览图，如下图
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
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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
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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
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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
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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; } |
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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
以上就是c# 实现网页加载后将页面截取为长图片的详细内容，更多关于c# 页面截取为图片的资料请关注服务器之家其它相关文章！
原文链接：https://www.cnblogs.com/lyl6796910/archive/2021/01/08/14250948.html
