A GitHub Copilot app canvas extension that renders mock-up gh output as VSCode-styled terminal screenshots. Built for producing marketing imagery (blog posts, changelogs, social) where real terminal recordings are impractical.

Open the canvas from a Copilot app session. Pick a starting mockup from the library dropdown, edit the content and toolbar options, and export a PNG via the download button. Files download through the browser/runtime, which typically lands them in the configured downloads directory.

The toolbar controls font, font size, width, window chrome (macOS or none), backdrop (subtle blue glow / grid / none), and an "auto-style" toggle that colorizes common gh patterns without requiring inline tags.

Content can be authored as raw ANSI escapes, or with a more readable bracket syntax that the renderer maps to the VSCode Dark+ palette:

• Named colors: [red], [green], [yellow], [blue], [magenta], [cyan], [white], [black] (bright variants prefixed br, e.g. [brblue]), plus [muted] for grayed-out text and [link] for blue underlined link styling.
• Modifiers: [bold] (or [b]), [italic] (or [i]), [underline] (or [u]), [dim].
• Each tag closes with its matching [/name], e.g. [red]error[/red].

When auto-style is on, the renderer also colorizes PR/issue states, labels, checkboxes, timestamps, and similar conventional output without explicit tags.

Mockups live in two locations:

• Project library at ./library/*.json: committed to the repo, the shared starting set.
• User library at $COPILOT_HOME/extensions/terminal-mockup/artifacts/*.json: local-only, for personal experiments.

Saving a new mockup writes to the user library by default; renaming an existing one preserves its scope. The dropdown shows both, prefixed by scope.

assets/html2canvas.min.js is the unmodified html2canvas 1.4.1 distribution (MIT). Used to rasterize the rendered DOM into a PNG in-browser.