Added pasting and sending features

src/EbbesMemeClipboard/Services/ClipboardService.cs

@@ -3,6 +3,7 @@ using System.IO;
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Windows;
+using System.Windows.Media.Imaging;
 
 namespace EbbesMemeClipboard.Services;
 
@@ -10,8 +11,6 @@ public sealed class ClipboardService : IClipboardService
 {
     public async Task CopyLocalFileAsync(string filePath)
     {
-        bool isGif = ImageDecoding.IsGif(filePath);
-
         var firstFrame = await Task.Run(() => ImageDecoding.DecodeFirstFrame(filePath));
 
         var data = new DataObject();
@@ -23,18 +22,36 @@ public sealed class ClipboardService : IClipboardService
         // WPF's DataObject.SetImage auto-converts to CF_DIB - no manual header work needed here.
         data.SetImage(firstFrame);
 
-        if (isGif)
-        {
-            // CF_HTML: the format most browser/rich-text paste targets use, and the only one of
-            // the three that preserves animation for those targets (CF_DIB is a single frame).
-            var bytes = await File.ReadAllBytesAsync(filePath);
-            var fragment = $"<img src=\"data:image/gif;base64,{Convert.ToBase64String(bytes)}\">";
-            data.SetData(DataFormats.Html, BuildCfHtml(fragment));
-        }
+        // "PNG": a registered clipboard format (not one of the classic CF_* constants) that
+        // Chromium-based apps specifically look for and prefer over CF_DIB/CF_BITMAP when
+        // reading a pasted image, because those older formats are lossy for transparency. This
+        // covers Teams, Slack, Discord's web layer, and browsers - without it, paste into any of
+        // them can silently produce nothing even though CF_DIB is present and perfectly valid.
+        using var pngStream = new MemoryStream();
+        var pngEncoder = new PngBitmapEncoder();
+        pngEncoder.Frames.Add(BitmapFrame.Create(firstFrame));
+        pngEncoder.Save(pngStream);
+        pngStream.Position = 0;
+        data.SetData("PNG", pngStream);
+
+        // CF_HTML: the other route those same web-based paste targets check, and the only one of
+        // these formats that preserves animation for them, for GIFs.
+        var bytes = await File.ReadAllBytesAsync(filePath);
+        var fragment = $"<img src=\"data:{GetMimeType(filePath)};base64,{Convert.ToBase64String(bytes)}\">";
+        data.SetData(DataFormats.Html, BuildCfHtml(fragment));
 
         await SetClipboardWithRetryAsync(data);
     }
 
+    private static string GetMimeType(string filePath) =>
+        Path.GetExtension(filePath).ToLowerInvariant() switch
+        {
+            ".png" => "image/png",
+            ".jpg" or ".jpeg" => "image/jpeg",
+            ".gif" => "image/gif",
+            _ => "application/octet-stream",
+        };
+
     private static async Task SetClipboardWithRetryAsync(DataObject data)
     {
         const int maxAttempts = 5;