Copy and Cut made the system clipboard's formats in the frame that ran
them. The formats include the SVG markup and a PNG of the selection at
1 px per pt, up to 4,096 px a side. In a release build on Windows, Copy
of 50,002 rectangles on a 1600 x 1200 pt page took 1.00 s in its frame.
The thread that writes background saves and exports now makes the
formats from a copy of the clipboard, and the app writes them in a
later frame. The same Copy takes 0.18 s in its frame, and the SVG and
PNG are the same bytes. While that thread has a save, an export, a print or
a recovery copy to finish, Copy and Cut make and write the formats at
once. A later Copy or Cut, or text copied in a field or with the Type
tool, drops formats that are not written yet. Until they are written,
Paste on the canvas takes the internal clipboard, and while a text
field or the Type tool has the keyboard the app waits for them.
Docs: docs/mcp.md, docs/target-app-parity.md.