Easily implement thumbnails in DOTNET with C #

zhaozj2021-02-12  153

Previously, the thumbnail on the page must be used to use a third party component. Now, with .NET, thumbnails can be easily implemented. Below is an example of achieving thumbnails.

Keywords: C #, ASP.NET, thumbnail

Example Download: http://www.lionsky.net/mywebsite/downsoft/list.aspx? Id = 221

TOTHUMBNAILIMAGE.ASPX

<% @ Page language = "c #" Codebehind = "ToThumbnailImage.aspx.cs" Src = "ToThumbnailImage.aspx.cs" AutoEventWireup = "false" Inherits = "Exam_C.ToThumbnailImage"%> Lion Interactive Network => Generate Thumbnail </ Title> </ head> <body> <form id = "form1" method = "post" runat = "server"> </ form> </ body> </ html></p> <p>TOTHUMBNAILIMAGE.ASPX.CS</p> <p>using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls Using system.Web.ui.htmlControls; Using System.drawing.Imaging; Namespace Exam_c {/// <summary> /// TothumbnailImage Summary Description. /// </ summary> public class tothumbnailimage: system.Web.ui.page {/ * create by lion 2003-05-20 19:00 Copyright (c) 2004 www.lionsky.net. All Rights Reserved. Web: http : //www.lionsky.net; email: lion-a@sohu.com * /</p> <p>Static hashtable htmimes = new hashtable (); internal readonly string allowext = ".jpe | .jpeg | .jpg | .png | .tif | .tiff | .bmp"; #REGON Web Form Designer Generated Code Override Protected Void OnInit (Eventargs E) {#Region Htmimes ["JPE"] = "image / jpeg"; htmimes ["jpeg"] = "image / jpeg"; htmimes ["jpg"] = "image / jpeg"; HTMIMES ["PNG"] = "image / png"; htmimes [". TIF"] = "image / TIFF"; htmimes ["TIFF"] = "image / TIFF"; htmimes [". BMP"] = "image / bmp"; #ndregion // Call generation thumbnail method TothumbnailImages, "B.GIF", 300);} # endregion # region helper /// <summary> /// Get image encoding All related information of the decoder /// </ summary> /// <param name = "MIMETYPE"> Contains a multi-purpose Internet Snail Extension Protocol (MIME) type of the encoded decoder </ param> /// < returns> returns all image codec information </ returns> static ImageCodecInfo GetCodecInfo (string mimeType) {ImageCodecInfo [] CodecInfo = ImageCodecInfo.GetImageEncoders (); foreach (ImageCodecInfo ici in CodecInfo) {if (ici.MimeType == mimeType Return ICI;} return null;}</p> <p>/// <summary> /// detects the validity of the extension /// </ summary> /// <param name = "sext"> file name extension </ param> /// <returns> If the extension Effective, return true, otherwise returning false. </ Returns> BOOL CheckvaliDext (String sext) {bool flag = false; string [] ate = allowext.split ('|'); foreach (string filetype in aext) {ix .Tolower () == sext) {flag = true; Break;}} Return Flag;</p> <p>/// <summary> /// Save Picture /// <//// <param name = "image"> image object </ param> /// <param name = "savepath"> save the path </ param> /// <param name = "ici"> parameter specifies codec format </ param> void SaveImage (System.Drawing.Image image, string savePath, ImageCodecInfo ici) {// set the object original image object EncoderParameters EncoderParameters Parameters = New EncoderParameters (1); parameters.Param [0] = new encoderparameter (Encoder.quality, ((long) 90)); Image.Save (SavePath, ICI, Parameters); parameters.dispose ();} #ENDREGION #Region Methods</p> <p>/// <summary> /// Generate thumbnail /// </ summary> /// <param name = "sourceImagePath"> original image path (relative path) </ param> /// <parame = "thumbnailimagePath "> The resulting thumbnail path, if saved as the original picture path (relative path) </ param> /// <param name =" thumbnailimageWidth "> The width of the thumbnail (height is automatically generated by the source image proportion) </ param> public void ToThumbnailImages (string sourceImagePath, string thumbnailImagePath, int thumbnailImageWidth) {string sourceImagePath = sourceImagePath; string thumbnailImagePath = thumbnailImagePath; int thumbnailImageWidth = thumbnailImageWidth; string sExt = SourceImagePath.Substring ( "." SourceImagePath.LastIndexOf ()). ToLower (); if (SourceImagePath.ToString () == System.String.Empty) throw new NullReferenceException ( "SourceImagePath is null!"); (! CheckValidExt (sExt)) if {throw new ArgumentException ( "the original image file format does not Correctly, supported formats have [" Allowext "] "," SourceImagePath ");} // Create an Image object from the original image System.drawing.Image.fromfile (httpContext.current.server. Mappath (SourceImagePath)); int Num = ((thumbnailimagewidth / 4) * 3) Int width = image.width; int Height = image.Height; // Calculate the proportion of pictures IF ((Double) Width) / ((Double) Height)> = 1.333333333333331F) {Num = ((Height * ThumbnailimageWidth) / width);} else {thumbnailimageWidth = (width * Num) / height);}} ((ThumbnailImageWidth <1) || (Num <1)) {return;} // initialize with the specified size and format BitMap class Bitmap Bitmap = New Bitmap (thumbnailimagewidth, num, pixelformat.format32bppargb); // Create a new Graphics object from the specified image object graphics graphics = graphics.FromImage (Bitmap);</p> <p>/ / Clear the entire drawing and populate graphics.clear (color.TransParent) in transparent background; // Draw the original picture object in the specified location and press the specified size (Image, New Rectangle (0, 0, ThumbnailImageWidth, Num )); image.Dispose (); try {// this original image to the specified format and saved with the specified codec parameter to specify the file string savepath = (ThumbnailImagePath == null SourceImagePath:? ThumbnailImagePath); SaveImage (bitmap, HttpContext. CURRENT.SERVER.MAPPATH (SavePath), getCodecInfo ((String) htmimes [sext]));} catch (system.exception e) {throw e;} finally {bitmap.dispose (); graphics.dispose ();}} #ndregion}}}</p></div><div class="text-center mt-3 text-grey"> 转载请注明原文地址:https://www.9cbs.com/read-6655.html</div><div class="plugin d-flex justify-content-center mt-3"></div><hr><div class="row"><div class="col-lg-12 text-muted mt-2"><i class="icon-tags mr-2"></i><span class="badge border border-secondary mr-2"><h2 class="h6 mb-0 small"><a class="text-secondary" href="tag-2.html">9cbs</a></h2></span></div></div></div></div><div class="card card-postlist border-white shadow"><div class="card-body"><div class="card-title"><div class="d-flex justify-content-between"><div><b>New Post</b>(<span class="posts">0</span>) </div><div></div></div></div><ul class="postlist list-unstyled"> </ul></div></div><div class="d-none threadlist"><input type="checkbox" name="modtid" value="6655" checked /></div></div></div></div></div><footer class="text-muted small bg-dark py-4 mt-3" id="footer"><div class="container"><div class="row"><div class="col">CopyRight © 2020 All Rights Reserved </div><div class="col text-right">Processed: <b>0.035</b>, SQL: <b>9</b></div></div></div></footer><script src="./lang/en-us/lang.js?2.2.0"></script><script src="view/js/jquery.min.js?2.2.0"></script><script src="view/js/popper.min.js?2.2.0"></script><script src="view/js/bootstrap.min.js?2.2.0"></script><script src="view/js/xiuno.js?2.2.0"></script><script src="view/js/bootstrap-plugin.js?2.2.0"></script><script src="view/js/async.min.js?2.2.0"></script><script src="view/js/form.js?2.2.0"></script><script> var debug = DEBUG = 0; var url_rewrite_on = 1; var url_path = './'; var forumarr = {"1":"Tech"}; var fid = 1; var uid = 0; var gid = 0; xn.options.water_image_url = 'view/img/water-small.png'; </script><script src="view/js/wellcms.js?2.2.0"></script><a class="scroll-to-top rounded" href="javascript:void(0);"><i class="icon-angle-up"></i></a><a class="scroll-to-bottom rounded" href="javascript:void(0);" style="display: inline;"><i class="icon-angle-down"></i></a></body></html><script> var forum_url = 'list-1.html'; var safe_token = 'Otb1escWf2PW_2BF4FkxIHBO1dSuhxOOB20Ergt_2FLvgSX7kFSNaBmgJYAZDZF80PsrLcHLzHA3RYnNNFcd'; var body = $('body'); body.on('submit', '#form', function() { var jthis = $(this); var jsubmit = jthis.find('#submit'); jthis.reset(); jsubmit.button('loading'); var postdata = jthis.serializeObject(); $.xpost(jthis.attr('action'), postdata, function(code, message) { if(code == 0) { location.reload(); } else { $.alert(message); jsubmit.button('reset'); } }); return false; }); function resize_image() { var jmessagelist = $('div.message'); var first_width = jmessagelist.width(); jmessagelist.each(function() { var jdiv = $(this); var maxwidth = jdiv.attr('isfirst') ? first_width : jdiv.width(); var jmessage_width = Math.min(jdiv.width(), maxwidth); jdiv.find('img, embed, iframe, video').each(function() { var jimg = $(this); var img_width = this.org_width; var img_height = this.org_height; if(!img_width) { var img_width = jimg.attr('width'); var img_height = jimg.attr('height'); this.org_width = img_width; this.org_height = img_height; } if(img_width > jmessage_width) { if(this.tagName == 'IMG') { jimg.width(jmessage_width); jimg.css('height', 'auto'); jimg.css('cursor', 'pointer'); jimg.on('click', function() { }); } else { jimg.width(jmessage_width); var height = (img_height / img_width) * jimg.width(); jimg.height(height); } } }); }); } function resize_table() { $('div.message').each(function() { var jdiv = $(this); jdiv.find('table').addClass('table').wrap('<div class="table-responsive"></div>'); }); } $(function() { resize_image(); resize_table(); $(window).on('resize', resize_image); }); var jmessage = $('#message'); jmessage.on('focus', function() {if(jmessage.t) { clearTimeout(jmessage.t); jmessage.t = null; } jmessage.css('height', '6rem'); }); jmessage.on('blur', function() {jmessage.t = setTimeout(function() { jmessage.css('height', '2.5rem');}, 1000); }); $('#nav li[data-active="fid-1"]').addClass('active'); </script>