---
id: T03
parent: S02
milestone: M002
provides: []
requires: []
affects: []
key_files: ["app/src/components/canvas/ObjectPanel.tsx", "app/src/components/canvas/AlignmentBar.tsx", "app/src/components/canvas/CanvasToolbar.tsx", "app/src/components/canvas/ShapeProperties.tsx", "app/src/views/DesignCanvas.tsx", "app/src/App.css"]
key_decisions: ["Extracted inline toolbar from DesignCanvas into standalone CanvasToolbar component with zoom and grid state", "ObjectPanel displays objects in reverse z-order (frontmost layer at top) matching standard design tool UX", "ShapeProperties uses type narrowing via discriminated union to show type-specific fields"]
patterns_established: []
drill_down_paths: []
observability_surfaces: []
duration: ""
verification_result: "Ran `cd app && npx tsc --noEmit` — zero type errors. Ran `cd app && npx vitest run --reporter=verbose` — all 71 tests pass (6 test files, 0 failures)."
completed_at: 2026-03-26T05:40:11.171Z
blocker_discovered: false
---

# T03: Built four canvas UI panels (ObjectPanel, AlignmentBar, CanvasToolbar, ShapeProperties) with full state wiring into DesignCanvas view

> Built four canvas UI panels (ObjectPanel, AlignmentBar, CanvasToolbar, ShapeProperties) with full state wiring into DesignCanvas view

## What Happened
---
id: T03
parent: S02
milestone: M002
key_files:
  - app/src/components/canvas/ObjectPanel.tsx
  - app/src/components/canvas/AlignmentBar.tsx
  - app/src/components/canvas/CanvasToolbar.tsx
  - app/src/components/canvas/ShapeProperties.tsx
  - app/src/views/DesignCanvas.tsx
  - app/src/App.css
key_decisions:
  - Extracted inline toolbar from DesignCanvas into standalone CanvasToolbar component with zoom and grid state
  - ObjectPanel displays objects in reverse z-order (frontmost layer at top) matching standard design tool UX
  - ShapeProperties uses type narrowing via discriminated union to show type-specific fields
duration: ""
verification_result: passed
completed_at: 2026-03-26T05:40:11.186Z
blocker_discovered: false
---

# T03: Built four canvas UI panels (ObjectPanel, AlignmentBar, CanvasToolbar, ShapeProperties) with full state wiring into DesignCanvas view

**Built four canvas UI panels (ObjectPanel, AlignmentBar, CanvasToolbar, ShapeProperties) with full state wiring into DesignCanvas view**

## What Happened

Created four React components forming the complete panel system around the canvas. ObjectPanel shows layers in reverse z-order with drag-to-reorder, visibility/lock toggles, and double-click rename. AlignmentBar provides 6 alignment + 2 distribute + center-on-artboard buttons using alignment utils from T01. CanvasToolbar replaces the inline toolbar with tool switcher, undo/redo, grid toggle, and zoom controls. ShapeProperties shows editable stroke/fill/dimensions/line-style/opacity for the selected shape. Updated DesignCanvas.tsx to wire all panels to useCanvasState and added comprehensive CSS to App.css.

## Verification

Ran `cd app && npx tsc --noEmit` — zero type errors. Ran `cd app && npx vitest run --reporter=verbose` — all 71 tests pass (6 test files, 0 failures).

## Verification Evidence

| # | Command | Exit Code | Verdict | Duration |
|---|---------|-----------|---------|----------|
| 1 | `cd app && npx tsc --noEmit` | 0 | ✅ pass | 2000ms |
| 2 | `cd app && npx vitest run --reporter=verbose` | 0 | ✅ pass | 2030ms |


## Deviations

None.

## Known Issues

None.

## Files Created/Modified

- `app/src/components/canvas/ObjectPanel.tsx`
- `app/src/components/canvas/AlignmentBar.tsx`
- `app/src/components/canvas/CanvasToolbar.tsx`
- `app/src/components/canvas/ShapeProperties.tsx`
- `app/src/views/DesignCanvas.tsx`
- `app/src/App.css`


## Deviations
None.

## Known Issues
None.
