feat(fonts): embed fonts into the solution (#16)

- Embed  `Captcha.Core.Resources.Fonts.Unifont.ttf` from assembly.
- Remove Arimo/Unifont installation steps from Dockerfile.
- Trim README prerequisites accordingly.

Author: ashtonav

README.md

@@ -63,7 +63,6 @@ curl -X 'POST' \
 - Visual Studio 2022
     - With ASP.NET and web development installed from the Visual Studio Installer
 - .NET 9 SDK
-- Arimo and Unifont fonts 
 
 #### How to Run
 1. Open the solution in Visual Studio 2022.

src/Captcha.Core/Captcha.Core.csproj

@@ -8,9 +8,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <None Remove="Resources\Fonts\Caveat-Bold.ttf" />
-    <None Remove="Resources\Fonts\Caveat-Regular.ttf" />
     <None Remove="Resources\Fonts\Caveat-SemiBold.ttf" />
+    <None Remove="Resources\Fonts\Unifont.ttf" />
   </ItemGroup>
 
   <ItemGroup>
@@ -19,11 +18,8 @@
   </ItemGroup>
 
   <ItemGroup>
-    <EmbeddedResource Include="Resources\Fonts\Caveat-Bold.ttf" />
-    <EmbeddedResource Include="Resources\Fonts\Caveat-Regular.ttf">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </EmbeddedResource>
     <EmbeddedResource Include="Resources\Fonts\Caveat-SemiBold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\Unifont.ttf" />
   </ItemGroup>
 
 </Project>

src/Captcha.Core/Constants.cs

@@ -10,8 +10,8 @@ public static class Constants
     public const int DefaultCaptchaHeight = 100;
     public const float DefaultFrequency = 100F;
     public const int FrequencyScalingFactor = 40000; // on a 400 x 100 image
-    public const string DefaultCaptchaFontName = "Arimo";
-    public const string DefaultCaptchaFallbackFontName = "Unifont";
+    public const string DefaultCaptchaFontName = "Captcha.Core.Resources.Fonts.Caveat-SemiBold.ttf";
+    public const string DefaultCaptchaFallbackFontName = "Captcha.Core.Resources.Fonts.Unifont.ttf";
     public static readonly SKColor DefaultPrimaryColor = SKColor.Parse("FFD3D3D3");
     public static readonly SKColor DefaultSecondaryColor = SKColor.Parse("FFFFFFFF");
     public const string CaptchaContentType = "image/jpeg";

src/Captcha.Core/Resources/Fonts/Caveat-Bold.ttf

@@ -6,6 +6,22 @@ namespace Captcha.Core.Services;
 
 public class CaptchaImageService : ICaptchaImageService
 {
+    private readonly SKTypeface _mainFontTypeface;
+    private readonly SKTypeface _fallbackFontTypeface;
+
+    public CaptchaImageService()
+    {
+        var assembly = typeof(CaptchaImageService).Assembly;
+
+        _mainFontTypeface = SKTypeface.FromStream(
+            assembly.GetManifestResourceStream(Constants.DefaultCaptchaFontName)
+        );
+
+        _fallbackFontTypeface = SKTypeface.FromStream(
+            assembly.GetManifestResourceStream(Constants.DefaultCaptchaFallbackFontName)
+        );
+    }
+
     public SKBitmap CreateCaptchaImage(CaptchaConfigurationData config)
     {
         var bitmap = new SKBitmap(new SKImageInfo(config.Width, config.Height));
@@ -73,7 +89,7 @@ private static void DrawWarpedText(CaptchaConfigurationData config, SKFont font,
         graphics.DrawPath(path, fillPaint);
     }
 
-    private static SKFont GetFontThatFitsRectangle(CaptchaConfigurationData config, SKRect rectangle)
+    private SKFont GetFontThatFitsRectangle(CaptchaConfigurationData config, SKRect rectangle)
     {
         var typeface = GetTypefaceThatCanRenderText(config.Text);
 
@@ -96,7 +112,6 @@ private static SKFont GetFontThatFitsRectangle(CaptchaConfigurationData config,
         return font;
     }
 
-
     private static void FillInTheBackground(CaptchaConfigurationData config, SKRect rectangle, SKCanvas graphics)
     {
         using var paint = new SKPaint
@@ -108,29 +123,18 @@ private static void FillInTheBackground(CaptchaConfigurationData config, SKRect
         graphics.DrawRect(rectangle, paint);
     }
 
-    private static SKTypeface GetTypefaceThatCanRenderText(string text)
+    private SKTypeface GetTypefaceThatCanRenderText(string text)
     {
-        // Try to load Caveat font from embedded resource
-        var assembly = typeof(CaptchaImageService).Assembly;
-        using var stream = assembly.GetManifestResourceStream("Captcha.Core.Resources.Fonts.Caveat-SemiBold.ttf");
-        if (stream != null)
+        using var mainFont = new SKFont(_mainFontTypeface);
+
+        if (mainFont.ContainsGlyphs(text))
         {
-            var typeface = SKTypeface.FromStream(stream);
-            if (typeface != null)
-            {
-                var font = new SKFont(typeface);
-                if (font.ContainsGlyphs(text))
-                {
-                    return typeface;
-                }
-            }
+            return _mainFontTypeface;
         }
 
-        // Fallback if Caveat is missing or doesn't support text
-        return SKTypeface.FromFamilyName(Constants.DefaultCaptchaFallbackFontName);
+        return _fallbackFontTypeface;
     }
 
-
     /// <summary>
     /// This method applies similar logic to GraphicsPath.Warp() from System.Drawing.Common
     /// https://stackoverflow.com/questions/48416118/perspective-transform-in-skia

src/Captcha.Core/Resources/Fonts/Caveat-Regular.ttf

@@ -3,14 +3,6 @@
 # This stage is used when running from VS in fast mode (Default for Debug configuration)
 FROM mcr.microsoft.com/dotnet/aspnet:9.0-noble AS base
 
-# -- INSTALL FONTS USED TO RENDER CAPTCHA IMAGES --
-RUN apt-get update -y
-# Install Arimo
-RUN apt-get --no-install-recommends install -y fonts-croscore
-# Install Unifont
-RUN apt-get --no-install-recommends install -y fonts-unifont
-# -------------------------------------------------
-
 USER $APP_UID
 WORKDIR /app
 EXPOSE 8080

src/Captcha.Core/Resources/Fonts/Unifont.ttf

@@ -23,11 +23,10 @@ public class ConstantsTests
     public void DefaultFrequencyShouldBe100() => Assert.That(Constants.DefaultFrequency, Is.EqualTo(100F));
 
     [Test]
-    public void DefaultCaptchaFontNameShouldBeArimo() => Assert.That(Constants.DefaultCaptchaFontName, Is.EqualTo("Arimo"));
+    public void DefaultCaptchaFontNameShouldBeCaveat() => Assert.That(Constants.DefaultCaptchaFontName, Is.EqualTo("Captcha.Core.Resources.Fonts.Caveat-SemiBold.ttf"));
 
     [Test]
-    public void FallbackCaptchaFontNameShouldBeUnifont() => Assert.That(Constants.DefaultCaptchaFallbackFontName, Is.EqualTo("Unifont"));
-
+    public void FallbackCaptchaFontNameShouldBeUnifont() => Assert.That(Constants.DefaultCaptchaFallbackFontName, Is.EqualTo("Captcha.Core.Resources.Fonts.Unifont.ttf"));
 
     [Test]
     public void DefaultPrimaryColorShouldBeDarkGray() => Assert.That(Constants.DefaultPrimaryColor, Is.EqualTo(SKColor.Parse("FFD3D3D3")));