eng-pad/PROGRESS.md

PROGRESS.md — eng-pad Implementation Progress

This file tracks completed work and decisions. Updated after every step. See PROJECT_PLAN.md for the full step list.

Completed

Phase 0: Project Documents (2026-03-24)

• 0.1: Created DESIGN.md — full technical design covering architecture, data model, coordinate system, rendering, input handling, and source tree.
• 0.2: Created PROJECT_PLAN.md — discrete steps grouped by phase with checkboxes and file references.
• 0.3: Created PROGRESS.md — this file.
• 0.4: Updated CLAUDE.md — build commands, source tree, project doc pointers.

Phase 1: Project Skeleton + Data Layer (2026-03-24)

• 1.1: Generated Android project — Gradle 8.14.2, AGP 8.10.1, Kotlin 2.1.20
• 1.2: Version catalog with Compose BOM 2026.03.00, Room 2.8.4, Navigation 2.9.7, Lifecycle 2.10.0
• 1.3: Lint configured — warningsAsErrors, AGP version check suppressed (AGP 9.x needs Gradle 9.x)
• 1.4: Room entities: Notebook, Page, Stroke, PageSize enum
• 1.5: Converters: FloatArray ↔ ByteArray (packed little-endian)
• 1.6: DAOs: NotebookDao, PageDao, StrokeDao
• 1.7: EngPadDatabase (Room, version 1)
• 1.8: NotebookRepository, PageRepository
• 1.9: Unit tests: StrokeBlobTest (6 tests), PageSizeTest (4 tests) — all pass
• Foojay resolver added for automatic JDK toolchain download
• compileSdk/targetSdk bumped to 36 (required by latest androidx dependencies)

Phase 2: Notebook List Screen (2026-03-24)

• 2.1: MainActivity with Compose NavHost (three routes: notebooks, pages, editor)
• 2.2: NotebookListViewModel with StateFlow, create/delete operations
• 2.3: NotebookListScreen — lazy list, create dialog (title + page size radio), long-press delete with confirmation, empty state
• 2.4: Auto-create page 1 in NotebookRepository.create()
• 2.5: Navigation wired — tap notebook → pages stub, editor stub
• EngPadTheme: high-contrast light color scheme (black on white for e-ink)

Phase 3: Canvas — Basic Drawing (2026-03-24)

• 3.1–3.4: PadCanvasView — stylus input with historical points, Path/Paint stroke rendering, direct path drawing (no backing bitmap), 60pt grid drawn in screen space with pixel-snapped positions, Matrix coordinate transform (canonical ↔ screen)
• 3.5: CanvasState — tool enum (PEN_FINE, PEN_MEDIUM, ERASER, SELECT, BOX), zoom/pan state, pen width constants (4.49pt, 5.91pt)
• 3.6: EditorViewModel — loads strokes from Room, saves on completion
• 3.7: EditorScreen + Toolbar — Compose wrapper with AndroidView, FilterChip toolbar for pen size and eraser selection
• 3.8: NavGraph updated — pages route auto-navigates to first page's editor, page size passed through route params
• Used KTX Canvas extensions (withMatrix, withScale, createBitmap) per lint
• ClickableViewAccessibility suppressed on PadCanvasView (drawing view)

Phase 4: Zoom and Pan (2026-03-24)

• 4.1: ScaleGestureDetector with focal-point zoom (dynamic min–4×)
• 4.2: Finger drag for pan with multi-pointer tracking, pan clamped so page always fills viewport
• 4.3: Input routing by tool type already in place from Phase 3
• Zoom/pan state managed locally in PadCanvasView for responsiveness, synced to ViewModel on gesture end
• Minimum zoom computed dynamically from page/view dimensions

Phase 5: Eraser (2026-03-24)

• 5.1–5.3: Stroke-level eraser with bounding box hit test (42pt radius), processes historical touch points for thorough erasing, deletes from view + Room DB

Phase 6: Undo/Redo (2026-03-24)

• 6.1: UndoableAction interface, AddStrokeAction, DeleteStrokeAction
• 6.2: UndoManager with undo/redo stacks (depth 50), StateFlow for canUndo/canRedo
• 6.3: EditorViewModel rewired — stroke add/delete go through UndoManager, visual callbacks sync canvas view without full reload
• 6.4: 9 unit tests for UndoManager (perform, undo, redo, depth limit, clear, no-ops)
• Toolbar now has undo/redo buttons with enabled state

Phase 7: Selection — Move, Copy, Delete (2026-03-24)

• 7.1–7.2: Rectangle selection with dashed rect and blue highlight
• 7.3: Delete, drag-to-move, copy operations with toolbar buttons
• 7.4: Full undo integration — DeleteMultipleStrokesAction, MoveStrokesAction, CopyStrokesAction
• Drag existing selection to move, tap outside to deselect

Phase 8: Multi-Page Navigation (2026-03-24)

• 8.1: PageListScreen — adaptive grid of page cards with correct aspect ratio
• 8.2: Add new page via FAB
• 8.3: NavGraph refactored — pages route loads notebook metadata then shows PageListScreen, tap page navigates to editor with page size

Phase 9: PDF Export (2026-03-24)

• 9.1: PdfExporter — creates PdfDocument, scales canonical 300 DPI coords to 72 DPI PDF points (×0.24), renders strokes without grid
• 9.2: Share via Intent.ACTION_SEND + FileProvider (configured in Phase 1)
• 9.3: PDF button in editor toolbar, exports current page

Phase 10: Polish (2026-03-24)

• 10.1: High-contrast e-ink theme — expanded color scheme with proper container, variant, and outline colors for readability
• 10.2: Auto-save already in place since Phase 3 (strokes save on completion)
• 10.3: Empty states and delete confirmations already in place from Phase 2
• 10.4: Performance profiling — requires on-device testing

On-Device Testing — Daylight DC-1 (2026-03-24)

Tested on DC-1, identified and fixed rendering issues:

• Grid: original grid drawn in canonical space had uneven spacing due to sub-pixel positioning when scaled. Fixed by drawing grid in screen space with pixel-snapped line positions. Now uniform squares.
• Stroke quality: original backing bitmap at 1/4 resolution caused blurry strokes. Fixed by removing backing bitmap entirely and drawing paths directly. Anti-aliasing disabled on all paint for crisp e-ink lines.
• Viewport: dark gray background was visible around page edges. Fixed by clamping pan to page edges, computing dynamic min zoom, and white background.
• Box tool: works correctly on device.
• PDF export: correctly elides grid — confirmed on device.
• Line snap: increased threshold to 60pt (~5mm) and switched to max-distance tracking to handle EMR stylus hand tremor.

Status

All implementation phases complete. Remaining work:

• Test on Supernote Manta
• Verify line snap behavior on device
• Performance profiling with heavily annotated pages

Decisions & Deviations

• Language: Kotlin (chosen over Java for better Compose/coroutine support).
• Storage: Room/SQLite with packed float BLOBs for stroke points.
• Palm rejection: Hardware only (EMR digitizer handles it).
• Pressure sensitivity: None — two fixed pen sizes (0.38mm, 0.5mm).
• Coordinate system: 300 DPI canonical points (scaled to 72 DPI for PDF export).
• UI framework: Compose for chrome, custom View for canvas (Compose Canvas lacks MotionEvent access needed for stylus input).