# Sketch 9UY MVP Progress

## Date

April 17, 2026

## Scope

Started implementation of the Sketch 9UY MVP defined in `PRD.md`.

## Completed

- Replaced the placeholder page with a working sketchpad shell.
- Added a responsive 9UY-style layout with:
  - header
  - toolbar
  - canvas area
  - about panel
  - footer links
- Implemented MVP drawing features:
  - pen tool
  - eraser tool
  - color picker
  - brush size control
  - undo
  - redo
  - clear canvas
  - PNG export
- Added keyboard shortcuts for:
  - `B` pen
  - `E` eraser
  - `[` and `]` brush size
  - `Ctrl/Cmd + Z` undo
  - `Ctrl/Cmd + Shift + Z` redo
- Added Pointer Events support for mouse, touch, and stylus input.
- Added a service worker for basic app-shell caching.
- Updated the manifest metadata to better match the MVP.

## Current Implementation Notes

- The canvas uses a single raster drawing surface.
- Undo/redo is snapshot-based for simplicity and reliability in the MVP.
- The export format is PNG only.
- The canvas background is currently white to keep exports predictable.

## Not Yet Implemented

- Shape tools
- Background switching
- Opacity control
- Text tool
- Layers
- JPEG export
- SVG export
- Draft persistence across reloads

## Known Risks / Follow-Up

- Snapshot-based history is simple but may become memory-heavy during very long sessions.
- Canvas resize currently preserves the latest drawing state by redraw scaling, which is acceptable for MVP but not ideal for precision artwork.
- There is no draft autosave yet, so reloads still lose work.

## Recommended Next Steps

1. Add a mobile-first toolbar refinement pass.
2. Add background selection with transparent-aware export rules.
3. Replace snapshot history with stroke-based history if performance becomes an issue.
4. Add shape tools after core drawing UX feels solid.