EchoHub/docs/auriondocs/Code/src/EchoHub.Client/Services/ClipboardImage.cs.md

ClipboardImage

File: src/EchoHub.Client/Services/ClipboardImage.cs
Kind: class

public static class ClipboardImage

Reads raw image bytes from the platform clipboard and returns them as a PNG byte array when available. Use ClipboardImage.TryGetPng when you need a canonical, pasteable PNG representation of whatever image the user has on the clipboard (for example, when accepting pasted screenshots or images in a terminal or chat input that cannot accept raw bitmap data).

Remarks

ClipboardImage centralizes platform-specific clipboard handling: TryGetPng dispatches to TryGetWindows, TryGetLinux, or TryGetMacOS depending on OperatingSystem checks, and normalizes all outputs to PNG. When the clipboard format already contains PNG bytes (detected using the PngMagic signature or platform-registered PNG formats such as those discovered via RegisterClipboardFormatW on Windows), the bytes are passed through to preserve fidelity and transparency. When the clipboard exposes a DIB/bitmap (CfDib on Windows), the DibToPng helper builds a minimal BMP wrapper around the DIB bytes, decodes it with Image.Load, and re-encodes the result as PNG; this covers screenshots and editors that expose only device-independent bitmaps.

The class intentionally swallows and logs exceptions (via Log.Warning) from clipboard access and image decoding so callers get a simple success/failure result from TryGetPng instead of propagating clipboard or image-library exceptions.

Notes

• Clipboard APIs are platform and threading sensitive. On Windows the OS clipboard typically requires running on an STA thread; calling TryGetPng from a non-STA thread may fail or return false. Ensure clipboard access is performed on an appropriate thread context for the platform.
• DibToPng validates the DIB header (minimum 40 bytes, header size bounds) and returns null for malformed input. Decoding can still fail at Image.Load for unsupported or corrupted bitmaps; such failures are logged and surface as a failure to TryGetPng.
• Re-encoding a DIB to PNG may not preserve alpha/transparency if the original bitmap format lacks alpha channels (DIB/CF_DIB often does not include alpha). If preserving exact alpha semantics is required, prefer sources that supply native PNG clipboard formats when possible.
• Converting clipboard data allocates buffers (the BMP wrapper and the resulting PNG byte array) and performs image decode/encode work; callers should expect a non-trivial CPU and memory cost for large images.