使用背景：
關于滑動驗證碼的使用場所還是非常多的，如： 調取短信介面之前，和 注冊請求之前 或者 頻繁會呼叫的介面 都需要加這個拼圖驗證，這里先上一下效果圖吧（心中無碼，自然高清），
話不多說，開擼！
實作分析：
滑動驗證碼的邏輯也很簡單，大概說一下：
1，服務器生成主圖+附圖（從主圖裁剪下來的不需要管y坐標）并且存盤X坐標；
2，前端傳入本地X坐標到服務器，
3，服務器進行計算存盤X坐標和本地X坐標相差值；
4，驗證相差值是否在 0-2 之間，判斷 true | false
后端代碼：
準備：
增加SlideCaptcha檔案夾，并且增加Captcha.cs CaptchaModel.cs Config.cs ImgFormat.cs 4個檔案，分別是：驗證，驗證物體，配置和圖片生成類，代碼如下：
Captcha.cs
using System; using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.IO; using System.Net; namespace SliderCaptcha.NET { public class Captcha { public static Captcha64Model GenerateBase64() { CaptchaModel model = Captcha.Generate(); if (model != null) { return new Captcha64Model() { X = model.X, Y = model.Y, Background = ImageToBase64(model.Background,ImageFormat.Jpeg), Slide = ImageToBase64(model.Slide, ImageFormat.Png) }; } else { return null; } } /// <summary> /// 生成驗證碼 /// </summary> /// <returns></returns> public static CaptchaModel Generate() { Bitmap image = BgImage(); if (image != null) { int l = Config.l; int d = Config.d; int width = image.Width; int height = image.Height; int x = RandomNext(width / 3, width - d - l - 10);//初始x int y = RandomNext(10 + d, height - l - 10); ;//初始y GraphicsPath path = GetSliderPath(x, y); Graphics g = GetGraphics(image); //水印 if (Config.showWatermark) { Font font = new Font("宋體", 12, FontStyle.Bold); SizeF size = g.MeasureString(Config.watermarkText, font); Point Plogo = new Point((int)(width - size.Width - 5), (int)(height - size.Height - 5)); Color color = image.GetPixel(Plogo.X, Plogo.Y); SolidBrush bru = new SolidBrush(AntiColor(color)); g.DrawString(Config.watermarkText, font, bru, Plogo); } Pen pen = new Pen(Color.FromArgb(200, 255, 255, 255), 2); g.DrawPath(pen, path); Image slider = CaptureSlider(image, path, x, width, height); SolidBrush brush = new SolidBrush(Color.FromArgb(100, 255, 255, 255)); g.FillPath(brush, path); g.Save(); g.Dispose(); return new CaptchaModel() { X = x, Y = y, Background = image, Slide = slider }; } return null; } /// <summary> /// 獲取圖片Graphics /// </summary> /// <param name="image"></param> /// <returns></returns> private static Graphics GetGraphics(Image image) { Graphics g = Graphics.FromImage(image); g.SmoothingMode = SmoothingMode.HighQuality; g.CompositingQuality = CompositingQuality.HighQuality; g.InterpolationMode = InterpolationMode.High; return g; } /// <summary> /// 獲取滑塊path /// </summary> private static GraphicsPath GetSliderPath(int x, int y) { int l = Config.l; int r = Config.r; int b = Config.b; int c = Config.c; int d = Config.d; int blod = Config.blod; GraphicsPath path = new GraphicsPath(FillMode.Winding); Point Pa = new Point(x, y); Point Pb = new Point(x + l / 2 - b, y - c + blod); Point Pd = new Point(x + l, y); Point Pe = new Point(Pd.X + c - blod, y + l / 2 - b); Point Pg = new Point(Pd.X, y + l); Point Ph = new Point(x, y + l); Point Pj = new Point(x + c - blod, Pe.Y); path.AddLine(Pa, Pb); path.AddArc(x + l / 2 - r, y - d, d, d, 130f, 280f); path.AddLines(new Point[] { Pd, Pe }); path.AddArc(x + l, y + l / 2 - r, d, d, 220f, 280f); path.AddLines(new Point[] { Pg, Ph }); path.AddArc(x, y + l / 2 - r, d, d, 140f, -280f); path.AddLine(Pj, Pa); return path; } /// <summary> /// 獲取滑塊區域 /// </summary> /// <param name="image"></param> /// <param name="path"></param> /// <param name="x"></param> /// <param name="width"></param> /// <param name="height"></param> /// <returns></returns> private static Image CaptureSlider(Image image, GraphicsPath path, int x, int width, int height) { Bitmap concave = new Bitmap(image.Width, image.Height); Graphics g = GetGraphics(concave); TextureBrush brush = new TextureBrush(image); g.Clear(Color.Transparent); g.FillPath(brush, path); g.Dispose(); return CaptureImage(concave, x, height); } /// <summary> /// 裁剪圖片 /// </summary> /// <param name="fromImage"></param> /// <param name="offsetX"></param> /// <param name="width"></param> /// <param name="height"></param> /// <returns></returns> private static Image CaptureImage(Image fromImage, int offsetX, int height) { int width = Config.l + Config.d + Config.blod; Bitmap bitmap = new Bitmap(width, height); Graphics g = GetGraphics(bitmap); g.DrawImage(fromImage, 0, 0, new Rectangle(offsetX, 0, width, height), GraphicsUnit.Pixel); g.Dispose(); return bitmap; } /// <summary> /// 生成亂數 /// </summary> /// <param name="min"></param> /// <param name="max"></param> /// <returns></returns> private static int RandomNext(int min, int max) { Random random = new Random(Guid.NewGuid().GetHashCode()); return random.Next(min, max); } /// <summary> /// 取反色 /// </summary> /// <param name="color"></param> /// <returns></returns> public static Color AntiColor(Color color) { if (color.R > 128 && color.G > 128 && color.B > 128) { return Color.Black; } else { return Color.White; } } /// <summary> /// 獲取背景圖 /// </summary> /// <returns></returns> private static Bitmap BgImage() { WebClient web = new WebClient(); int num = RandomNext(1, 20); Stream stream = web.OpenRead($"http://00x1.com/images/Pic/{num}.jpg"); Bitmap bitmap = (Bitmap)Image.FromStream(stream); return bitmap; } /// <summary> /// base64轉圖片 /// </summary> /// <param name="base64string"></param> /// <returns></returns> public static Bitmap Base64ToImage(string base64string) { byte[] b = Convert.FromBase64String(base64string); MemoryStream ms = new MemoryStream(b); Bitmap bitmap = new Bitmap(ms); return bitmap; } /// <summary> /// 圖片轉base64 /// </summary> /// <param name="image"></param> /// <returns></returns> public static string ImageToBase64(Image image, ImageFormat format) { if (image == null) return string.Empty; string strbaser64 = ""; try { string head = ""; string formatName = ImgFormat.NameFromGuid(format); head = $"data:image/{formatName.ToLower()};base64,"; MemoryStream ms = new MemoryStream(); image.Save(ms, format); byte[] arr = new byte[ms.Length]; ms.Position = 0; ms.Read(arr, 0, (int)ms.Length); ms.Close(); strbaser64 = head+Convert.ToBase64String(arr); } catch (Exception) { throw new Exception("Something wrong during convert!"); } return strbaser64; } } }
CaptchaModel.cs
using System; using System.Collections.Generic; using System.Drawing; using System.Linq; using System.Text; namespace SliderCaptcha.NET { public class CaptchaModel { public int X { get; set; } public int Y { get; set; } public Image Background { get; set; } public Image Slide { get; set; } } public class Captcha64Model { public int X { get; set; } public int Y { get; set; } public string Background { get; set; } public string Slide { get; set; } } }
Config.cs
using System; namespace SliderCaptcha.NET { public class Config { /// <summary> /// 矩形寬 /// </summary> public static int l = 42; /// <summary> /// 圓形半徑 /// </summary> public static int r = 9; /// <summary> /// 圓形直徑 /// </summary> public static int d = r * 2; /// <summary> /// 計算圓形與矩形交接三角形邊 /// </summary> public static int a = (int)(r * Math.Sin(Math.PI * (50 / 180f))); public static int b = (int)(r * Math.Cos(Math.PI * (50 / 180f))); public static int c = r - a; /// <summary> /// 滑塊邊框 /// </summary> public static int blod = 2; /// <summary> /// 水印 /// </summary> public static string watermarkText = "SC.NET"; /// <summary> /// 是否顯示水印 /// </summary> public static bool showWatermark = true; } }
ImgFormat.cs
using System; using System.Collections.Generic; using System.Drawing.Imaging; namespace SliderCaptcha.NET { public class ImgFormat { private static Dictionary<string, string> Formats = new Dictionary<string, string>() { {"b96b3caa-0728-11d3-9d7b-0000f81ef32e","MemoryBmp"}, {"b96b3cab-0728-11d3-9d7b-0000f81ef32e","Bmp"}, {"b96b3cac-0728-11d3-9d7b-0000f81ef32e","Emf"}, {"b96b3cad-0728-11d3-9d7b-0000f81ef32e","Wmf"}, {"b96b3cae-0728-11d3-9d7b-0000f81ef32e","Jpeg"}, {"b96b3caf-0728-11d3-9d7b-0000f81ef32e","Png"}, {"b96b3cb0-0728-11d3-9d7b-0000f81ef32e","Gif"}, {"b96b3cb1-0728-11d3-9d7b-0000f81ef32e","Tiff"}, {"b96b3cb2-0728-11d3-9d7b-0000f81ef32e","Exif"}, {"b96b3cb5-0728-11d3-9d7b-0000f81ef32e","Icon"} }; public static ImageFormat FormatFromGuid(ImageFormat format) { return FormatFromGuid(format.Guid); } public static ImageFormat FormatFromGuid(Guid guid) { return FormatFromGuid(guid.ToString()); } public static ImageFormat FormatFromGuid(string guid) { if (Formats.ContainsKey(guid)) { string name = Formats[guid]; ImageFormat format = null; switch (name) { case "MemoryBmp": format = ImageFormat.MemoryBmp; break; case "Bmp": format = ImageFormat.Bmp; break; case "Emf": format = ImageFormat.Emf; break; case "Wmf": format = ImageFormat.Wmf; break; case "Gif": format = ImageFormat.Gif; break; case "Jpeg": format = ImageFormat.Jpeg; break; case "Png": format = ImageFormat.Png; break; case "Tiff": format = ImageFormat.Tiff; break; case "Exif": format = ImageFormat.Exif; break; case "Icon": format = ImageFormat.Icon; break; } return format; } else { return null; } } public static string NameFromGuid(ImageFormat format) { return NameFromGuid(format.Guid); } public static string NameFromGuid(Guid guid) { return NameFromGuid(guid.ToString()); } public static string NameFromGuid(string guid) { if (Formats.ContainsKey(guid)) { return Formats[guid]; } else { return string.Empty; } } } }
使用：
這里用的是asp.net mvc 的框架，用的是api介面，前后端分離供前端使用，具體使用根據個人需求，可以是介面呼叫亦可以是專案呼叫，
呼聲如果很高的話，考慮出一個winfrom版本的滑動驗證碼~（滑稽）
[HttpGet] public IHttpActionResult GetCaptcha() { Captcha64Model model = Captcha.GenerateBase64(); CacheHelper.Cache.SetCache("sliderX", model.X); Hashtable ht = new Hashtable(); ht.Add("background", model.Background); ht.Add("slider", model.Slide); ht.Add("sliderXXXXX", model.X); return Json(ht); } /// <summary> /// 檢查驗證 /// </summary> /// <param name="x"></param> /// <returns></returns> [HttpPost] public IHttpActionResult CheckCaptcha([FromBody] int x = 0) { Hashtable hs = new Hashtable(); string Mess = ""; int Code = 0; var session = CacheHelper.Cache.GetCache("sliderX"); if (session == null) { Mess = "請重繪驗證碼"; Code = 500; goto block; } string sliderXStr = session?.ToString();// as string int sliderX = Convert.ToInt32(sliderXStr); int difX = sliderX - x; if (difX >= 0 - Config.blod && difX <= Config.blod) { Mess = "success"; Code = 0; } else { session = null; Mess = "錯誤"; Code = 500; } block: hs.Add("Mess", Mess); hs.Add("Code", Code); return Json(hs); }
前端代碼：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <title>Splide Captcha</title> <style> * { -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; } .sc-captcha { width: 300px; margin: 100px auto; } .sc_net_panel { padding: 10px; } .sc_net_panel > div { position: relative; } .bg_slider { position: absolute; left: 0; top: 0; } .bg_refresh { position: absolute; right: 5px; top: 5px; background: #808080; color: #fff; border-radius: 3px; width: 16px; line-height: 16px; text-align: center; cursor: pointer; } .sc_net_slider_icon { position: absolute; left: 0; top: 0; height: 37px; text-align: center; border-radius: 5px; border: #808080 1px solid; width: 37px; line-height: 37px; cursor: pointer; } .sc_net_slider_icon:hover { color: #fff; background: #1991fa; } .sc_net_slider_text { position: absolute; left: 0; top: 0; text-align: center; width: 280px; color: #45494c; border: #808080 1px solid; border-radius: 5px; line-height: 35px; height: 37px; cursor: default; } .sc_net_slider_area { position: absolute; left: 0; top: 0; height: 37px; } </style> <script src=https://www.cnblogs.com/BFMC/p/"E:\porject\碚煜Api\ByzkApi\Scripts\jquery-3.4.1.js"></script> <script src=https://www.cnblogs.com/BFMC/p/"E:\porject\碚煜Api\ByzkApi\Scripts\jquery-3.4.1.min.js"></script> </head> <body> <div> <div class="sc-captcha"> <div class="sc_net_panel"> <div class="sc_net_bg"> <div class="sc_net_bgimg"> </div> <div class="bg_refresh" onclick="loadCaptcha()" title="重繪">?</div> </div> </div> <div class="sc_net_panel"> <div class="sc_net_slider"> <div class="sc_net_slider_text">向右拖動滑塊填充拼圖</div> <div class="sc_net_slider_area"></div> <div class="sc_net_slider_icon">?</div> </div> </div> </div> </div> </body> <script> loadCaptcha(); function loadCaptcha() { $.ajax({ url: "http://192.168.1.216:5500/api/TestApi/GetCaptcha", type: "Get", dataType: "JSON", success: function (json) { var bg = createCanvas(280, 155); bg.className = 'bg_img'; bg_slider = createCanvas(62, 155); bg_slider.className = 'bg_slider'; CanvasSetImage(bg, json.background); CanvasSetImage(bg_slider, json.slider); var doc = document.getElementsByClassName("sc_net_bgimg")[0]; doc.innerHTML = ""; doc.appendChild(bg); doc.appendChild(bg_slider); console.log(json.modelX); } }) } function createCanvas(width, height) { var canvas = document.createElement('canvas'); canvas.width = width; canvas.height = height; return canvas; }; function CanvasSetImage(_canvas, base64) { //獲取2d畫布物件 var ctx = _canvas.getContext("2d"); //創建圖片標簽 var _img = document.createElement("img"); //設定圖片地址 _img.src =https://www.cnblogs.com/BFMC/p/ base64; //ctx.fillRect(0, 0, _canvas.clientWidth, _canvas.clientHeight); //ctx.fillStyle = 'rgba(255, 255, 255, 0)'; _img.onload = function () { ctx.drawImage(_img, 0, 0); } /* ctx.drawImage(_img, 10, 10);*/ } function getByClassName0(className) { return document.getElementsByClassName(className)[0]; }; var slider = getByClassName0("sc_net_slider_icon"); var text = getByClassName0("sc_net_slider_text"); var area = getByClassName0("sc_net_slider_area"); var bg_slider; slider.addEventListener('mousedown', handleDragStart); slider.addEventListener('touchstart', handleDragStart); document.addEventListener('mousemove', handleDragMove); document.addEventListener('touchmove', handleDragMove); document.addEventListener('mouseup', handleDragEnd); document.addEventListener('touchend', handleDragEnd); document.addEventListener('mousedown', function () { return false; }); document.addEventListener('touchstart', function () { return false; }); var originX, originY, trail = [], isMouseDown = false; var isOk = false; function handleDragStart(e) { console.log("handleDragStart"); if (isOk) return; originX = e.clientX || e.touches[0].clientX; originY = e.clientY || e.touches[0].clientY; isMouseDown = true; }; function handleDragMove(e) { if (!isMouseDown) return false; var eventX = e.clientX || e.touches[0].clientX; var eventY = e.clientY || e.touches[0].clientY; var moveX = eventX - originX; var moveY = eventY - originY; if (moveX >= 0 && moveX <= 243) { slider.style.left = moveX + "px"; bg_slider.style.left = moveX / 243 * 218 + "px"; } }; function handleDragEnd(e) { if (!isMouseDown) return false isMouseDown = false var eventX = e.clientX || e.changedTouches[0].clientX if (eventX == originX) return false //獲取前端的x坐標； var a = $(".bg_slider"); var localX = a[0].offsetLeft; $.ajax({ url: "http://192.168.1.216:5500/api/TestApi/CheckCaptcha?x=" + localX, type: "Post", dataType: "JSON", success: function (res) { alert(res.Mess); } }) }; </script> </html>
結語：
到這里基本上就已經完成了，以上前端地址更換成自己的介面即可，正常業務 驗證碼是很頻發的一個操作并且是多用戶，所以快取存盤的時候也需要注意一下，最后有問題的話，可以評論區溝通，感謝觀看！（這次很用心在寫，能否上個推薦~）
從前慢，車馬慢， 一生只愛一個人，
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/460698.html
標籤：ASP.NET
上一篇：選擇非聚合列的計數