C#实现的上传图片、保存图片、加水印、生成缩略图功能示例
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2023-12-10 09:29:28
本文实例讲述了c#实现的上传图片、保存图片、加水印、生成缩略图功能。分享给大家供大家参考,具体如下:
伴随移动设备地普及,处理图片、视频等需求也变得越来越基础,这里介绍的...
本文实例讲述了c#实现的上传图片、保存图片、加水印、生成缩略图功能。分享给大家供大家参考,具体如下:
伴随移动设备地普及,处理图片、视频等需求也变得越来越基础,这里介绍的是图片的存储。
上传图片必须使用form表单提交的方式,我只知道这一种方法,如果大家知道其他方法的话请留言。
保存图片、加水印和生成缩略图这三种功能最好各自放在单独的方法中,尽量降低耦合度,提高代码复用程度,除此之外我们平常写代码是也要尽量做到方法功能的唯一性。
前台代码:
<form method="post" enctype="multipart/form-data" action="uploadimg.ashx"> <table> <tr> <td>func:</td> <td><input type="text" name="func"/></td> </tr> <tr> <td>用户id:</td> <td><input type="text" name="userid"/></td> </tr> <tr> <td>头像:</td> <td><input type="file" name="icon"/></td> </tr> <tr> <td>水印:</td> <td><input type="text" name="watermark"/></td> </tr> </table> <input type="submit" value="提交"/> </form>
后台代码:
private string uploadimage(httpcontext context) { try { system.io.stream stream = context.request.files["icon"].inputstream; //返回的图片路径可以存储在数据库中 string imageurl = saveimage(stream, "icon", "蝈蝈"); string thumbnailimageurl = savethumbnailimage(stream, "icon"); string thumbnailimageurlwithwatermark = savethumbnailimage(configurationmanager.appsettings["attachmentsdirectory"] + imageurl, "icon"); return "上传成功!"; } catch (exception ex) { return "上传失败!"; } } private string saveimage(stream stream, string foldername, string watermark) { try { string filename = guid.newguid() + ".jpg"; string path = configurationmanager.appsettings["attachmentsdirectory"]; path = path.combine(path, foldername + "\\" + datetime.now.year + "\\" + datetime.now.month + "\\" + datetime.now.day + "\\"); string imageurl = "/" + foldername + "/" + datetime.now.year + "/" + datetime.now.month + "/" + datetime.now.day + "/"; if (!string.isnullorempty(watermark)) { image imgsource = image.fromstream(stream); addwatermarkandsave(path, filename, watermark, imgsource, imgsource.height - 300, 10, color.red, new font("宋体", 40)); } else { byte[] buffer = new byte[stream.length]; stream.read(buffer, 0, buffer.length); if (!directory.exists(path)) { directory.createdirectory(path); } system.io.filestream fs = new system.io.filestream(path + filename, system.io.filemode.openorcreate, system.io.fileaccess.write); fs.write(buffer, 0, buffer.length); fs.flush(); fs.close(); } return imageurl + filename; } catch (exception ex) { return ""; } } private string savethumbnailimage(stream stream, string foldername) { try { string filename = guid.newguid() + ".jpg"; string path = configurationmanager.appsettings["attachmentsdirectory"]; path = path.combine(path, foldername + "\\" + datetime.now.year + "\\" + datetime.now.month + "\\" + datetime.now.day + "\\"); string imageurl = "/" + foldername + "/" + datetime.now.year + "/" + datetime.now.month + "/" + datetime.now.day + "/"; system.drawing.image.getthumbnailimageabort mycallback = new system.drawing.image.getthumbnailimageabort(getfalse); //数据源来自stream image image = system.drawing.bitmap.fromstream(stream); system.drawing.image thumbnailimage = image.getthumbnailimage(64, 64, mycallback, intptr.zero); thumbnailimage.save(path + filename); thumbnailimage.dispose(); return imageurl + filename; } catch (exception ex) { return ""; } } private string savethumbnailimage(string originalfilename, string foldername) { try { string filename = guid.newguid() + ".jpg"; string path = configurationmanager.appsettings["attachmentsdirectory"]; path = path.combine(path, foldername + "\\" + datetime.now.year + "\\" + datetime.now.month + "\\" + datetime.now.day + "\\"); string imageurl = "/" + foldername + "/" + datetime.now.year + "/" + datetime.now.month + "/" + datetime.now.day + "/"; system.drawing.image.getthumbnailimageabort mycallback = new system.drawing.image.getthumbnailimageabort(getfalse); //数据源来自file image image = system.drawing.bitmap.fromfile(originalfilename); system.drawing.image thumbnailimage = image.getthumbnailimage(64, 64, mycallback, intptr.zero); thumbnailimage.save(path + filename); thumbnailimage.dispose(); return imageurl + filename; } catch (exception ex) { return ""; } } private bool getfalse() { return false; } /// <summary> /// 图片加文字水印 /// </summary> /// <param name="filename"> </param> /// <param name="text">水印文字,如果是多行用分号隔开</param> /// <param name="img">图片</param> /// <param name="paddingtop">上边距</param> /// <param name="paddingleft">左边距</param> /// <param name="textcolor">文字颜色</param> /// <param name="textfont">字体</param> /// <param name="path">保存地址</param> /// <returns></returns> private bool addwatermarkandsave(string path, string filename, string text, image img, int paddingtop, int paddingleft, color textcolor, font textfont) { text = text + ";" + "当前时间:" + datetime.now.tostring("yyyy-mm-dd hh:mm"); if (!directory.exists(path)) { directory.createdirectory(path); } textfont = new font("宋体", 19); bitmap bm = new bitmap(img); system.drawing.graphics g = system.drawing.graphics.fromimage(bm); system.drawing.brush b = new solidbrush(textcolor); string[] str = text.split(';'); for (int i = 0; i < str.length; i++) g.drawstring(str[i], textfont, b, paddingleft, paddingtop + 33 * i); g.dispose(); bm.save(path + filename, imageformat.jpeg); bm.dispose(); return true; }
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希望本文所述对大家c#程序设计有所帮助。