Add /speechbubble command (#37)

src/Numerous.Bot/Discord/Interactions/Commands/SpeechBubbleCommandModule.cs

@@ -0,0 +1,93 @@
+// Copyright (C) Pasi4K5 <https://www.github.com/Pasi4K5>
+// This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+// This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+// You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+using System.Reflection;
+using Discord;
+using Discord.Interactions;
+using JetBrains.Annotations;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+using Image = SixLabors.ImageSharp.Image;
+
+namespace Numerous.Bot.Discord.Interactions.Commands;
+
+public sealed class SpeechBubbleCommandModule(IHttpClientFactory clientFactory) : InteractionModule
+{
+    [UsedImplicitly]
+    [SlashCommand("speechbubble", "Generates a speech bubble meme with the given image")]
+    public async Task SpeechBubble(
+        [Summary("image", "Source image")]
+        IAttachment attachment
+    )
+    {
+        if (!attachment.ContentType.StartsWith("image/"))
+        {
+            await RespondWithEmbedAsync(
+                message: "The file you uploaded is not an image.",
+                type: ResponseType.Error
+            );
+
+            return;
+        }
+
+        var speechBubbleStream = Assembly.GetExecutingAssembly().GetManifestResourceStream("Numerous.Bot.Resources.speech_bubble.png");
+
+        if (speechBubbleStream is null)
+        {
+            throw new FileNotFoundException("Could not find 'speech_bubble.png'.");
+        }
+
+        await DeferAsync();
+
+        using var speechBubble = await Image.LoadAsync<Rgba32>(speechBubbleStream);
+
+        using var client = clientFactory.CreateClient();
+        await using var customImageStream = await client.GetStreamAsync(attachment.Url);
+
+        try
+        {
+            var customImage = await Image.LoadAsync<Rgba32>(customImageStream);
+
+            var customImageAspectRatio = (float)customImage.Width / customImage.Height;
+            var speechBubbleAspectRatio = (float)speechBubble.Width / speechBubble.Height;
+            speechBubble.Mutate(x => x.Resize(new Size(
+                customImage.Width,
+                (int)Math.Floor((double)customImage.Width / speechBubbleAspectRatio / customImageAspectRatio)))
+            );
+
+            using var result = new Image<Rgba32>(customImage.Width, customImage.Height);
+
+            for (var y = 0; y < customImage.Height; y++)
+            {
+                for (var x = 0; x < customImage.Width; x++)
+                {
+                    if (y < speechBubble.Height)
+                    {
+                        var imgPixel = customImage[x, y];
+                        var maskPixel = speechBubble[x, y];
+                        var alpha = (double)maskPixel.R / 255;
+                        result[x, y] = new Rgba32(imgPixel.R, imgPixel.G, imgPixel.B, (byte)Math.Round(alpha * imgPixel.A));
+                    }
+                    else
+                    {
+                        result[x, y] = customImage[x, y];
+                    }
+                }
+            }
+
+            using var resultStream = new MemoryStream();
+            await result.SaveAsPngAsync(resultStream);
+            await FollowupWithFileAsync(resultStream, "speech_bubble.png");
+        }
+        catch (UnknownImageFormatException)
+        {
+            await FollowupWithEmbedAsync(
+                message: "This image format is not supported.",
+                type: ResponseType.Error
+            );
+        }
+    }
+}

src/Numerous.Bot/Numerous.Bot.csproj

@@ -26,11 +26,16 @@
 	  <PackageReference Include="Serilog.Exceptions" Version="8.4.0" />
 	  <PackageReference Include="Serilog.Sinks.Console" Version="6.0.0" />
 	  <PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
+	  <PackageReference Include="SixLabors.ImageSharp" Version="3.1.6" />
 	</ItemGroup>
 
 	<ItemGroup>
 	  <ProjectReference Include="..\Numerous.Common\Numerous.Common.csproj" />
 	  <ProjectReference Include="..\Numerous.Database\Numerous.Database.csproj" />
 	</ItemGroup>
+
+    <ItemGroup>
+        <EmbeddedResource Include="Resources\speech_bubble.png" />
+    </ItemGroup>
 
 </Project>