mirror of
https://github.com/RedWizardsLab/EchoHub.git
synced 2026-09-06 23:34:13 +02:00
feat: add clipboard image handling for pasting and staging attachments
This commit is contained in:
HueByte
@@ -0,0 +1,257 @@
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using System.Diagnostics;
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using System.Runtime.InteropServices;
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using System.Runtime.Versioning;
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using Serilog;
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using SixLabors.ImageSharp;
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namespace EchoHub.Client.Services;
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/// <summary>
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/// Reads raw image data from the OS clipboard (e.g. an image copied from a browser, or a
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/// Win+Shift+S screenshot), which terminals cannot paste as text. Always returns PNG bytes:
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/// clipboard PNG data is passed through, clipboard bitmaps (CF_DIB) are re-encoded.
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/// </summary>
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public static class ClipboardImage
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{
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private static readonly byte[] PngMagic = [0x89, 0x50, 0x4E, 0x47];
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public static bool TryGetPng(out byte[] png)
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{
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png = [];
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try
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{
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if (OperatingSystem.IsWindows())
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return TryGetWindows(out png);
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if (OperatingSystem.IsLinux())
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return TryGetLinux(out png);
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if (OperatingSystem.IsMacOS())
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return TryGetMacOS(out png);
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}
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catch (Exception ex)
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{
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Log.Warning(ex, "Reading an image from the clipboard failed");
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}
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return false;
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}
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private static bool IsPng(byte[] data) =>
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data.Length > PngMagic.Length && data.AsSpan(0, PngMagic.Length).SequenceEqual(PngMagic);
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/// <summary>
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/// Converts clipboard DIB bytes (a BITMAPINFOHEADER/V4/V5 + optional palette/masks + pixel
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/// data, i.e. a .bmp file without its 14-byte file header) to PNG. Returns null when the
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/// data is malformed or not decodable as a bitmap.
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/// </summary>
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public static byte[]? DibToPng(byte[] dib)
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{
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if (dib.Length < 40)
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return null;
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var headerSize = BitConverter.ToInt32(dib, 0);
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if (headerSize < 40 || headerSize > dib.Length)
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return null;
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var bitCount = BitConverter.ToUInt16(dib, 14);
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var compression = BitConverter.ToUInt32(dib, 16);
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var clrUsed = BitConverter.ToUInt32(dib, 32);
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// Pixel data offset: file header + info header + color masks + palette.
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// BI_BITFIELDS masks follow a plain 40-byte header; larger headers embed them.
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var maskBytes = headerSize == 40 && compression == 3 ? 12
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: headerSize == 40 && compression == 6 ? 16
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: 0;
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var paletteEntries = clrUsed != 0 ? clrUsed
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: bitCount <= 8 ? 1u << bitCount
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: 0u;
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var pixelOffset = (uint)(14 + headerSize + maskBytes) + paletteEntries * 4;
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var bmp = new byte[14 + dib.Length];
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bmp[0] = (byte)'B';
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bmp[1] = (byte)'M';
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BitConverter.TryWriteBytes(bmp.AsSpan(2), (uint)bmp.Length);
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BitConverter.TryWriteBytes(bmp.AsSpan(10), pixelOffset);
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dib.CopyTo(bmp, 14);
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try
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{
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using var image = Image.Load(bmp);
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using var ms = new MemoryStream();
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image.SaveAsPng(ms);
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return ms.ToArray();
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}
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catch (Exception ex) when (ex is ImageFormatException or InvalidOperationException)
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{
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Log.Warning(ex, "Clipboard DIB could not be decoded as a bitmap");
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return null;
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}
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}
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// ── Windows: "PNG" / "image/png" registered formats, then CF_DIB ─────────
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private const uint CfDib = 8;
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[SupportedOSPlatform("windows")]
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private static bool TryGetWindows(out byte[] png)
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{
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png = [];
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// Browsers register a "PNG" (Chromium) or "image/png" (some apps) clipboard format
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// preserving transparency; CF_DIB is synthesized by Windows for everything else
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// (screenshots, image editors), so together these cover all image sources.
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var pngFormat = RegisterClipboardFormatW("PNG");
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var mimeFormat = RegisterClipboardFormatW("image/png");
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var hasAny = (pngFormat != 0 && IsClipboardFormatAvailable(pngFormat))
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|| (mimeFormat != 0 && IsClipboardFormatAvailable(mimeFormat))
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|| IsClipboardFormatAvailable(CfDib);
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if (!hasAny)
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return false;
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var opened = false;
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for (var attempt = 0; attempt < 5 && !opened; attempt++)
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opened = OpenClipboard(IntPtr.Zero);
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if (!opened)
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return false;
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try
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{
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foreach (var format in new[] { pngFormat, mimeFormat })
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{
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if (format == 0 || !IsClipboardFormatAvailable(format))
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continue;
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var data = ReadHGlobal(GetClipboardData(format));
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if (data is not null && IsPng(data))
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{
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png = data;
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return true;
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}
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}
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if (IsClipboardFormatAvailable(CfDib)
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&& ReadHGlobal(GetClipboardData(CfDib)) is { } dib
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&& DibToPng(dib) is { } converted)
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{
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png = converted;
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return true;
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}
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return false;
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}
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finally
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{
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CloseClipboard();
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}
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}
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[SupportedOSPlatform("windows")]
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private static byte[]? ReadHGlobal(IntPtr handle)
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{
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if (handle == IntPtr.Zero)
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return null;
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var ptr = GlobalLock(handle);
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if (ptr == IntPtr.Zero)
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return null;
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try
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{
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var size = (int)GlobalSize(handle);
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if (size <= 0)
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return null;
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var data = new byte[size];
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Marshal.Copy(ptr, data, 0, size);
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return data;
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}
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finally
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{
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GlobalUnlock(handle);
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}
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}
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[DllImport("user32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool OpenClipboard(IntPtr hWndNewOwner);
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[DllImport("user32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool CloseClipboard();
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[DllImport("user32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool IsClipboardFormatAvailable(uint format);
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[DllImport("user32.dll", SetLastError = true)]
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private static extern IntPtr GetClipboardData(uint uFormat);
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[DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
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private static extern uint RegisterClipboardFormatW(string lpszFormat);
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[DllImport("kernel32.dll", SetLastError = true)]
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private static extern IntPtr GlobalLock(IntPtr hMem);
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[DllImport("kernel32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool GlobalUnlock(IntPtr hMem);
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[DllImport("kernel32.dll", SetLastError = true)]
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private static extern nuint GlobalSize(IntPtr hMem);
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// ── Linux: image/png via wl-paste or xclip ────────────────────────────────
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[SupportedOSPlatform("linux")]
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private static bool TryGetLinux(out byte[] png)
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{
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png = [];
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var data = RunForBytes("wl-paste", ["--type", "image/png"])
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?? RunForBytes("xclip", ["-selection", "clipboard", "-t", "image/png", "-o"]);
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if (data is null || !IsPng(data))
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return false;
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png = data;
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return true;
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}
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// ── macOS: pngpaste (brew install pngpaste), when present ────────────────
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[SupportedOSPlatform("macos")]
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private static bool TryGetMacOS(out byte[] png)
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{
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png = [];
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var data = RunForBytes("pngpaste", ["-"]);
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if (data is null || !IsPng(data))
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return false;
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png = data;
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return true;
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}
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private static byte[]? RunForBytes(string fileName, IEnumerable<string> args)
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{
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var psi = new ProcessStartInfo(fileName)
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{
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RedirectStandardOutput = true,
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RedirectStandardError = true,
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UseShellExecute = false,
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CreateNoWindow = true,
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};
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foreach (var arg in args)
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psi.ArgumentList.Add(arg);
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try
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{
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using var process = Process.Start(psi);
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if (process is null)
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return null;
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using var ms = new MemoryStream();
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process.StandardOutput.BaseStream.CopyTo(ms);
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process.WaitForExit(2000);
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return process.ExitCode == 0 && ms.Length > 0 ? ms.ToArray() : null;
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}
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catch (Exception ex) when (ex is System.ComponentModel.Win32Exception or FileNotFoundException)
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{
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return null; // tool not installed
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}
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}
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}
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