一、原理及程序类型
原理:通过IE在本地打开目标URL同时截图;
本方法存在安全性的问题,千万不要为恶意网页生成缩略图,可能会给您带来一场灾难!
程序类型:C#语句(CS结构的程序)。
二、源代码
private void OnDocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) { WebBrowser browser = (sender as WebBrowser); if (browser != null) { mshtml.IHTMLDocument2 document = (browser.Document.DomDocument as mshtml.IHTMLDocument2); if (document != null) { mshtml.IHTMLElement element = (document.body as mshtml.IHTMLElement); if (element != null) { IHTMLElementRender render = (element as IHTMLElementRender); if (render != null) { using (Graphics graphics = this.CreateGraphics()) { IntPtr hdcDestination = graphics.GetHdc(); render.DrawToDC(hdcDestination); IntPtr hdcMemory = GDI32.CreateCompatibleDC(hdcDestination); IntPtr bitmap = GDI32.CreateCompatibleBitmap( hdcDestination, browser.ClientRectangle.Width, browser.ClientRectangle.Height ); if (bitmap != IntPtr.Zero) { IntPtr hOld = (IntPtr)GDI32.SelectObject(hdcMemory, bitmap); GDI32.BitBlt( hdcMemory, 0, 0, browser.ClientRectangle.Width, browser.ClientRectangle.Height, hdcDestination, 0, 0, TernaryRasterOperations.SRCCOPY ); GDI32.SelectObject(hdcMemory, hOld); GDI32.DeleteDC(hdcMemory); graphics.ReleaseHdc(hdcDestination); SaveThumbnail(Image.FromHbitmap(bitmap)); } } } } } } }
通过以上代码获取URL页面的内容之后,使用如下代码可生成缩略图
private void SaveThumbnail(Image image) { if (image != null) {//创建一个位图图像 Bitmap thumbnail = new Bitmap(160, 120, PixelFormat.Format24bppRgb); thumbnail.SetResolution(image.HorizontalResolution, image.VerticalResolution); using (Graphics resize = Graphics.FromImage(thumbnail)) { resize.InterpolationMode = InterpolationMode.HighQualityBicubic; resize.DrawImage(image, new Rectangle(0, 0, 160, 120), new Rectangle(0, 0, _webBrowser.ClientRectangle.Width, _webBrowser.ClientRectangle.Height), GraphicsUnit.Pixel); } thumbnail.Save(_file.FullName, ImageFormat.Png); } }
经过测试并验证,效果不是很好,但是还能使用,足够使用拉! 没有相关教程
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