众所周知,截止.Net Core 2.0, 目前官方类库的API中不支持Bitmap,System.Drawing.Primitives 这是官方的一个Drawing库,但是没有Bitmap、Graphics等很多东西,所以Core项目做图形验证码基本无法实现。但是可以通过引入第三方库ZKWeb.System.Drawing替代系统原生的库System.Drawing。这是一个兼容.Net Core的System.Drawing实现,由mono项目修改而来,适用于windows和linux。
Install-Package ZKWeb.System.Drawing -Version 4.0.1
@{ Layout = "../../Pages/Shared/_Layout.cshtml"; } <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>滑块验证-堆代码 duidaima.com</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; } .my_p { text-align:center; color:red; } </style> </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="刷新">↻</div> </div> </div> <div class="sc_net_panel1"> <div class="sc_net_panel"> <div class="sc_net_slider"> <div class="sc_net_slider_text">向右拖动滑块填充拼图</div> <div class="sc_net_slider_area"></div> <div id="table1" class="sc_net_slider_icon">➞</div> </div> </div> </div> </div> </div> <div> <div class="sc-captcha"> <div class="sc_net_panel"> <p id="msg" class="my_p"></p> </div> </div> </div> <script src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script> <script> var initial_x; //初始坐标 var end_x; //结束坐标 var slider = getByClassName0("sc_net_slider_icon"); //获取滑块 var bg_slider; //添加监听事件 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; }); //初始加载背景图片 window.onload = function (){ loadCaptcha(); } //获取图片数据 function loadCaptcha() { $.ajax({ url: "@Url.Action("GetCaptcha","SlideCapt")", type: "get", dataType: "JSON", crossDomain: true, success: function (json) { $("#table1").css("position", "absolute");//滑块恢复初始位置 $("#table1").css("left", 0);//滑块恢复初始位置 isMouseDown = false;//滑块禁止移动 var bg = createCanvas(280, 155); //定义画布大小 bg.className = 'bg_img'; //定义画布名称 bg_slider = createCanvas(62, 155); //定义滑块大小 bg_slider.className = 'bg_slider'; //定义滑块名称 CanvasSetImage(bg, json.background); //创建画布 CanvasSetImage(bg_slider, json.slider); //创建滑块 /*向界面添加节点*/ var doc = document.getElementsByClassName("sc_net_bgimg")[0]; doc.innerHTML = ""; doc.appendChild(bg); doc.appendChild(bg_slider); /*end*/ } }) } //设置画布,滑块的大小 function createCanvas(width, height) { var canvas = document.createElement('canvas'); canvas.width = width; canvas.height = height; return canvas; }; //创建画布,滑块 function CanvasSetImage(_canvas, base64) { //获取2d画布对象 var ctx = _canvas.getContext("2d"); //创建图片标签 var _img = document.createElement("img"); //设置图片地址 _img.src = base64; _img.onload = function () { ctx.drawImage(_img, 0, 0); } } //根据类名获取元素 function getByClassName0(className) { return document.getElementsByClassName(className)[0]; }; //originX originY初始坐标 //clientX clientY相对于界面的坐标 //screenX screenY相对于屏幕的坐标 //isMouseDown=true/false 滑块是否能移动 var originX, originY, trail = [], isMouseDown = false; var isOk = false; //滑块启动 function handleDragStart(e) { if (isOk) return; originX = e.screenX || e.touches[0].clientX; originY = e.screenY || e.touches[0].clientY; isMouseDown = true; initial_x = $(".bg_slider").offset().left; //获取初始坐标 }; //滑块拖动 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"; } }; //滑块结束 function handleDragEnd(e) { $("#msg").text(""); if (!isMouseDown) return false; isMouseDown = false; var eventX = e.clientX || e.changedTouches[0].clientX; if (eventX == originX) return false; end_x = $(".bg_slider").offset().left; //获取最终坐标 var result = Math.round(end_x - initial_x); $.post("@Url.Action("GetCaptcha","SlideCapt")"+ "?x=" + result, function (res) { if (res.Mess == "fail") { $("#msg").text("出错了,请重新尝试!"); handleDragStart(e); loadCaptcha(); } else { $("#msg").text("恭喜你,已打败80%的用户!"); } }); }; </script> </body> </html>生成验证码和主附图裁剪帮助类:
#region << 版 本 注 释 >> /*---------------------------------------------------------------- * 堆代码 duidaima.com * 创建时间:2023/8/21 10:25:35 * 版本:V1.0.0 * 描述: * * ---------------------------------------------------------------- * 修改人: * 时间: * 修改说明: * * 版本:V1.0.1 *----------------------------------------------------------------*/ #endregion << 版 本 注 释 >> using MyWebApp.Helper; using System; using System.DrawingCore; using System.DrawingCore.Drawing2D; using System.DrawingCore.Imaging; using System.IO; using System.Net; using Color = System.DrawingCore.Color; using Point = System.DrawingCore.Point; using Rectangle = System.DrawingCore.Rectangle; using SizeF = System.DrawingCore.SizeF; namespace MyWebApp.Common.SlideCaptcha { /// <summary> /// 生成验证码和裁剪帮助类 /// </summary> 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> /// 生成验证码 /// </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 height = 200; 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("宋体", 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> /// 获取图片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> /// 获取滑块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> /// 获取滑块区域 /// </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> /// 裁剪图片 /// </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> /// 生成随机数 /// </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> /// 获取背景图 /// </summary> /// <returns></returns> private static Bitmap BgImage() { try { int num = RandomNext(1, 60); #region 外部图片 WebClient web = new WebClient(); //Stream stream = web.OpenRead($"http://00x1.com/images/Pic/{num}.jpg"); #endregion #region 自定义图片 string rootPath = Directory.GetCurrentDirectory() + @"\wwwroot\captImages\"; string imagePath = rootPath + $"{num}.jpg"; Stream stream = FileHelper.FileToStream(imagePath); #endregion //Bitmap bitmap = (Bitmap)Image.FromStream(stream); Bitmap bitmap = new Bitmap(imagePath); return bitmap; } catch (Exception ex) { return null; } } /// <summary> /// base64转图片 /// </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> /// 图片转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; } } }
验证码请求和验证接口:
[Route("[controller]")] [ApiController] public class SlideCaptController : Controller { [HttpGet] public IActionResult GetCaptcha() { Captcha64Model model = Captcha.GenerateBase64(); CacheHelper.SetCache("sliderX", model.X); Hashtable ht = new Hashtable(); ht.Add("background", model.Background); ht.Add("slider", model.Slide); ht.Add("sliderX", model.X); return Json(ht); } /// <summary> /// 检查验证 /// </summary> /// <param name="x"></param> /// <returns></returns> [HttpPost] public IActionResult CheckCaptcha([FromQuery] int x = 0) { Hashtable hs = new Hashtable(); string Mess = ""; int Code = 0; var session = CacheHelper.GetCache("sliderX"); if (session == null) { Mess = "请刷新验证码"; 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 = "fail"; Code = 500; } block: hs.Add("Mess", Mess); hs.Add("Code", Code); return Json(hs); } }
四、演示
本地准备的验证码图片: