From 64a803456f2536dc4ad85e60ef85bd59b3fe0d0a Mon Sep 17 00:00:00 2001
From: Edi Wang <Edi.Wang@outlook.com>
Date: Sun, 11 Aug 2024 13:03:27 +0800
Subject: [PATCH] code refact

---
 src/Edi.Captcha/CaptchaImageGenerator.cs | 109 ++++++++++++-----------
 src/Edi.Captcha/Edi.Captcha.csproj       |   2 +-
 2 files changed, 59 insertions(+), 52 deletions(-)

diff --git a/src/Edi.Captcha/CaptchaImageGenerator.cs b/src/Edi.Captcha/CaptchaImageGenerator.cs
index 0297093..6af2d7d 100644
--- a/src/Edi.Captcha/CaptchaImageGenerator.cs
+++ b/src/Edi.Captcha/CaptchaImageGenerator.cs
@@ -12,74 +12,81 @@ namespace Edi.Captcha;
 
 public static class CaptchaImageGenerator
 {
+    private static readonly Random Rand = new();
+
     public static CaptchaResult GetImage(
         int width, int height, string captchaCode, string fontName, FontStyle fontStyle = FontStyle.Regular, bool drawLines = true)
     {
         using var ms = new MemoryStream();
-        var rand = new Random();
 
-        using (var imgText = new Image<Rgba32>(width, height))
-        {
-            // characters layer
-            float position = 0;
-            var averageSize = width / captchaCode.Length;
-            var fontSize = Convert.ToInt32(averageSize);
+        var imgText = new Image<Rgba32>(width, height);
+        DrawCaptchaText(imgText, captchaCode, fontName, fontStyle);
 
-            Font font = SystemFonts.CreateFont(fontName, fontSize, fontStyle);
+        using var img = new Image<Rgba32>(width, height);
+        DrawBackground(img);
 
-            Random random = new Random();
+        if (drawLines)
+        {
+            DrawRandomLines(img, width, height);
+        }
 
-            foreach (char c in captchaCode)
-            {
-                var x = rand.Next(5, 10);
-                var y = rand.Next(6, 13);
+        // merge layers
+        img.Mutate(ctx => ctx.DrawImage(imgText, 1f));
+        img.SaveAsPng(ms);
 
-                var degrees = random.Next(0, 10) * (random.Next(-10, 10) > 0 ? 1 : -1);
+        return new CaptchaResult
+        {
+            CaptchaCode = captchaCode,
+            CaptchaByteData = ms.ToArray(),
+            Timestamp = DateTime.UtcNow
+        };
+    }
 
-                var location = new PointF(x + position, y);
-                imgText.Mutate(ctx =>
-                    ctx.SetDrawingTransform(Matrix3x2Extensions.CreateRotationDegrees(degrees, new(0, 0)))
-                        .DrawText(c.ToString(), font, GetRandomDeepColor(), location));
-                position += TextMeasurer.MeasureBounds(c.ToString(), new(font)).Width;
-            }
+    private static void DrawCaptchaText(Image<Rgba32> imgText, string captchaCode, string fontName, FontStyle fontStyle)
+    {
+        float position = 0;
+        var averageSize = imgText.Width / captchaCode.Length;
+        var fontSize = Convert.ToInt32(averageSize);
+        var font = SystemFonts.CreateFont(fontName, fontSize, fontStyle);
 
-            // background layer
-            int low = 180, high = 255;
-            var nRend = rand.Next(high) % (high - low) + low;
-            var nGreen = rand.Next(high) % (high - low) + low;
-            var nBlue = rand.Next(high) % (high - low) + low;
-            var backColor = Color.FromRgb((byte)nRend, (byte)nGreen, (byte)nBlue);
-            var img = new Image<Rgba32>(width, height);
-            img.Mutate(ctx => ctx.BackgroundColor(backColor));
+        foreach (var c in captchaCode)
+        {
+            var x = Rand.Next(5, 10);
+            var y = Rand.Next(6, 13);
+            var degrees = Rand.Next(-10, 10);
+            var location = new PointF(x + position, y);
 
-            if (drawLines)
-            {
-                // lines
-                for (var i = 0; i < rand.Next(3, 7); i++)
-                {
-                    var color = GetRandomDeepColor();
-                    var startPoint = new PointF(rand.Next(0, width), rand.Next(0, height));
-                    var endPoint = new PointF(rand.Next(0, width), rand.Next(0, height));
-                    img.Mutate(ctx => ctx.DrawLine(color, 1, startPoint, endPoint));
-                }
-            }
+            imgText.Mutate(ctx =>
+                ctx.SetDrawingTransform(Matrix3x2Extensions.CreateRotationDegrees(degrees, new PointF(0, 0)))
+                    .DrawText(c.ToString(), font, GetRandomDeepColor(), location));
 
-            // merge layers
-            img.Mutate(ctx => ctx.DrawImage(imgText, 1f));
-            img.SaveAsPng(ms);
+            position += TextMeasurer.MeasureBounds(c.ToString(), new(font)).Width;
         }
+    }
 
-        return new()
-        {
-            CaptchaCode = captchaCode,
-            CaptchaByteData = ms.ToArray(),
-            Timestamp = DateTime.UtcNow
-        };
+    private static void DrawBackground(Image<Rgba32> img)
+    {
+        var backColor = Color.FromRgb(
+            (byte)Rand.Next(180, 256),
+            (byte)Rand.Next(180, 256),
+            (byte)Rand.Next(180, 256));
+        img.Mutate(ctx => ctx.BackgroundColor(backColor));
+    }
 
-        Color GetRandomDeepColor()
+    private static void DrawRandomLines(Image<Rgba32> img, int width, int height)
+    {
+        for (var i = 0; i < Rand.Next(3, 7); i++)
         {
-            int redlow = 160, greenLow = 100, blueLow = 160;
-            return Color.FromRgb((byte)rand.Next(redlow), (byte)rand.Next(greenLow), (byte)rand.Next(blueLow));
+            var color = GetRandomDeepColor();
+            var startPoint = new PointF(Rand.Next(0, width), Rand.Next(0, height));
+            var endPoint = new PointF(Rand.Next(0, width), Rand.Next(0, height));
+            img.Mutate(ctx => ctx.DrawLine(color, 1, startPoint, endPoint));
         }
     }
+
+    private static Color GetRandomDeepColor()
+    {
+        int redlow = 160, greenLow = 100, blueLow = 160;
+        return Color.FromRgb((byte)Rand.Next(redlow), (byte)Rand.Next(greenLow), (byte)Rand.Next(blueLow));
+    }
 }
\ No newline at end of file
diff --git a/src/Edi.Captcha/Edi.Captcha.csproj b/src/Edi.Captcha/Edi.Captcha.csproj
index f0aa27b..f6d464f 100644
--- a/src/Edi.Captcha/Edi.Captcha.csproj
+++ b/src/Edi.Captcha/Edi.Captcha.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Version>3.23.1</Version>
+    <Version>3.24.0</Version>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <Company>edi.wang</Company>
     <Authors>Edi Wang</Authors>