Killed history

NadekoBot.Core/_Extensions/Rgba32Extensions.cs

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+using System.Collections.Generic;
+using System.Linq;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Formats.Gif;
+using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+
+namespace NadekoBot.Extensions
+{
+    public static class Rgba32Extensions
+    {
+        public static Image<Rgba32> Merge(this IEnumerable<Image<Rgba32>> images)
+        {
+            return images.Merge(out _);
+        }
+
+        public static Image<Rgba32> Merge(this IEnumerable<Image<Rgba32>> images, out IImageFormat format)
+        {
+            format = PngFormat.Instance;
+
+            void DrawFrame(Image<Rgba32>[] imgArray, Image<Rgba32> imgFrame, int frameNumber)
+            {
+                var xOffset = 0;
+                for (var i = 0; i < imgArray.Length; i++)
+                {
+                    var frame = imgArray[i].Frames.CloneFrame(frameNumber % imgArray[i].Frames.Count);
+                    imgFrame.Mutate(x => x.DrawImage(frame, new Point(xOffset, 0), new GraphicsOptions()));
+                    xOffset += imgArray[i].Bounds().Width;
+                }
+            }
+
+            var imgs = images.ToArray();
+            var frames = images.Max(x => x.Frames.Count);
+
+            var width = imgs.Sum(img => img.Width);
+            var height = imgs.Max(img => img.Height);
+            var canvas = new Image<Rgba32>(width, height);
+            if (frames == 1)
+            {
+                DrawFrame(imgs, canvas, 0);
+                return canvas;
+            }
+
+            format = GifFormat.Instance;
+            for (var j = 0; j < frames; j++)
+            {
+                using var imgFrame = new Image<Rgba32>(width, height);
+                DrawFrame(imgs, imgFrame, j);
+
+                var frameToAdd = imgFrame.Frames[0];
+                frameToAdd.Metadata.GetGifMetadata().DisposalMethod = GifDisposalMethod.RestoreToBackground;
+                canvas.Frames.AddFrame(frameToAdd);
+            }
+
+            canvas.Frames.RemoveFrame(0);
+            return canvas;
+        }
+    }
+}