Inspect Tool Implementation

Overview

The inspect (eyedropper) tool allows users to click on any ray in the optical system and view detailed information about that ray’s properties at the clicked position.

Features

1. Tool Activation

  • Location: Available in both the toolbar and Tools menu
  • Icon: Eyedropper icon (dummy placeholder for now)
  • Toggle: Click once to activate, click again to deactivate
  • Cursor: Changes to crosshair when active

2. Information Displayed

When clicking on a ray, the tool displays:

Position

  • X and Y coordinates in millimeters (scene coordinates)

Intensity

  • Current ray intensity as a percentage (0-100%)
  • Derived from the ray’s alpha channel

Wavelength

  • Ray wavelength in nanometers (if specified)
  • Shows “Not specified” for non-wavelength-specific rays

Polarization State

When polarization information is available:

Jones Vector: Complex electric field components [Ex, Ey]

Stokes Parameters:

  • I: Total intensity
  • Q: Horizontal/vertical polarization difference
  • U: Diagonal polarization difference
  • V: Circular polarization

Derived Properties:

  • Degree of Polarization: 0-100%
  • Linear Polarization Angle: -90° to +90°

Usage

  1. Activate the tool: Click the inspect icon in the toolbar or select Tools → Inspect
  2. Click on a ray: Click anywhere near a ray path
  3. View information: A dialog will display all ray properties at that location
  4. Close dialog: Click “Close” or press Escape
  5. Deactivate: Click the inspect icon again to return to normal mode

Technical Details

Click Detection

  • Tolerance: 15 pixels (zoom-independent)
  • Algorithm: Finds nearest ray point to click within tolerance
  • Zoom-aware: Tolerance scales with view zoom level for consistent UX

Data Storage

  • Each QGraphicsPathItem ray has corresponding RayPath data stored
  • ray_items list: Graphics items for rendering
  • ray_data list: Physics data (polarization, intensity, wavelength)

Integration

  • Automatically disabled when entering ruler placement mode
  • Event filter in MainWindow handles click events
  • Works with all ray types (primary, reflected, transmitted, refracted)

Code Structure

Main Components

  1. _build_actions(): Creates inspect action
  2. _build_toolbar(): Adds inspect button to toolbar
  3. _build_menubar(): Adds inspect to Tools menu
  4. _toggle_inspect(): Handles tool activation/deactivation
  5. _handle_inspect_click(): Finds clicked ray
  6. _show_ray_info_dialog(): Displays ray information

Data Flow 

retrace() 
  → trace_rays() returns RayPath objects
  → Store in ray_data list alongside ray_items
  → inspect click → find nearest point in ray_data
  → display dialog with polarization/intensity

Future Enhancements

Icon

  • Replace dummy icon with proper eyedropper icon
  • Could be designed in vector format (SVG) for better scaling

Display Improvements

  • Add visual feedback: highlight clicked ray
  • Show ray direction arrow
  • Display ray history (which elements it passed through)

Additional Information

  • Show which optical element the ray last interacted with
  • Display ray splitting history for beamsplitter rays
  • Show refractive index if inside a refractive object

Export

  • Add “Copy to Clipboard” button
  • Export ray information to CSV
  • Plot polarization state on Poincaré sphere

Testing

To test the inspect tool:

  1. Launch the application
  2. Add a light source
  3. Add some optical elements (mirrors, beamsplitters, waveplates)
  4. Enable auto-trace to see rays
  5. Click the inspect tool in the toolbar
  6. Click on various rays to see their properties

Test Cases

  • ✓ Click on primary ray from source
  • ✓ Click on reflected ray from mirror
  • ✓ Click on transmitted/reflected rays from beamsplitter
  • ✓ Click on polarization-modified ray after waveplate
  • ✓ Click on refracted ray through lens
  • ✓ Verify zoom-independent click tolerance
  • ✓ Verify tool deactivates when starting ruler placement