Initial first version.

2026-08-13 10:04:59 +02:00
parent df725b43c4
commit 940e80b630
22 changed files with 890 additions and 0 deletions
@@ -0,0 +1,82 @@
+using System.Collections.Specialized;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Windows;
+
+namespace EbbesMemeClipboard.Services;
+
+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();
+
+        // CF_HDROP: lets Discord/Slack/Teams/Explorer paste the real file (animated, for GIFs).
+        data.SetFileDropList(new StringCollection { filePath });
+
+        // CF_DIB fallback: apps that only accept bitmap paste (e.g. Paint) get a static image.
+        // 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));
+        }
+
+        await SetClipboardWithRetryAsync(data);
+    }
+
+    private static async Task SetClipboardWithRetryAsync(DataObject data)
+    {
+        const int maxAttempts = 5;
+        for (int attempt = 1; attempt <= maxAttempts; attempt++)
+        {
+            try
+            {
+                Clipboard.SetDataObject(data, copy: true);
+                return;
+            }
+            catch (COMException) when (attempt < maxAttempts)
+            {
+                // Another process is transiently holding the clipboard - back off and retry.
+                await Task.Delay(75);
+            }
+        }
+    }
+
+    /// <summary>
+    /// Builds a CF_HTML clipboard payload. WPF's DataObject.SetData(DataFormats.Html, ...) does
+    /// NOT wrap plain HTML into CF_HTML automatically - the Version/StartHTML/EndHTML/
+    /// StartFragment/EndFragment header with exact byte offsets has to be built by hand, or
+    /// paste targets will reject or mis-render the fragment.
+    /// </summary>
+    private static string BuildCfHtml(string htmlFragment)
+    {
+        const string prefix = "<html><body><!--StartFragment-->";
+        const string suffix = "<!--EndFragment--></body></html>";
+
+        int headerLength = Encoding.UTF8.GetByteCount(FormatHeader(0, 0, 0, 0));
+        int startHtml = headerLength;
+        int startFragment = startHtml + Encoding.UTF8.GetByteCount(prefix);
+        int endFragment = startFragment + Encoding.UTF8.GetByteCount(htmlFragment);
+        int endHtml = endFragment + Encoding.UTF8.GetByteCount(suffix);
+
+        return FormatHeader(startHtml, endHtml, startFragment, endFragment) + prefix + htmlFragment + suffix;
+    }
+
+    private static string FormatHeader(int startHtml, int endHtml, int startFragment, int endFragment) =>
+        "Version:0.9\r\n" +
+        $"StartHTML:{startHtml:D10}\r\n" +
+        $"EndHTML:{endHtml:D10}\r\n" +
+        $"StartFragment:{startFragment:D10}\r\n" +
+        $"EndFragment:{endFragment:D10}\r\n";
+}