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Mobile Chord System Implementation

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Overview

• Option key acts as a toggle/modifier
• When Option is pressed, it activates and waits for an arrow key
• When an arrow key is pressed while Option is active, it sends the combination
• Visual feedback shows when Option modifier is active

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Implementation Details

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1. State Management

• Added activeModifiers Set to track which modifiers are currently active
• Option key toggles its state in the Set rather than sending immediately

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2. Chord Detection

• When Option is pressed, it’s added to activeModifiers
• When an arrow key is pressed with Option active:
  • Clears the Option modifier
  • Sends Option (ESC) first
  • Then sends the arrow key
  • This creates the Option+Arrow combination

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3. Visual Feedback

• Added CSS class .modifier-key.active with blue background
• Option button shows active state when pressed
• State clears after arrow key press or when pressing non-arrow keys

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4. Key Mappings

• Option sends ESC (\x1b) - already implemented in direct-keyboard-manager.ts
• Arrow keys send their normal codes
• The combination results in ESC+arrow sequences for word navigation:
  • Option+Left = ESC+b (word backward)
  • Option+Right = ESC+f (word forward)

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Testing

• Toggle behavior of Option key
• Chord detection for all arrow keys
• Clearing of modifier state
• Visual update requests
• Multiple chord sequences

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Usage

1. Tap Option key (⌥) - it highlights in blue
2. Tap any arrow key - sends Option+Arrow combination
3. Option automatically deactivates after use
4. Can tap Option again to cancel without sending