LEDMatrix/wiki/DYNAMIC_DURATION_STOCKS_IMPLEMENTATION.md

Dynamic Duration Implementation for Stocks and Stock News

Overview

This document describes the implementation of dynamic duration functionality for the stock_manager and stock_news_manager classes, following the same pattern as the existing news_manager.

What Was Implemented

1. Configuration Updates

Added dynamic duration settings to both stocks and stock_news sections in config/config.json:

"stocks": {
    "enabled": true,
    "update_interval": 600,
    "scroll_speed": 1,
    "scroll_delay": 0.01,
    "toggle_chart": true,
    "dynamic_duration": true,
    "min_duration": 30,
    "max_duration": 300,
    "duration_buffer": 0.1,
    "symbols": [...],
    "display_format": "{symbol}: ${price} ({change}%)"
},
"stock_news": {
    "enabled": true,
    "update_interval": 3600,
    "scroll_speed": 1,
    "scroll_delay": 0.01,
    "max_headlines_per_symbol": 1,
    "headlines_per_rotation": 2,
    "dynamic_duration": true,
    "min_duration": 30,
    "max_duration": 300,
    "duration_buffer": 0.1
}

2. Stock Manager Updates (src/stock_manager.py)

Added Dynamic Duration Properties

# Dynamic duration settings
self.dynamic_duration_enabled = self.stocks_config.get('dynamic_duration', True)
self.min_duration = self.stocks_config.get('min_duration', 30)
self.max_duration = self.stocks_config.get('max_duration', 300)
self.duration_buffer = self.stocks_config.get('duration_buffer', 0.1)
self.dynamic_duration = 60  # Default duration in seconds
self.total_scroll_width = 0  # Track total width for dynamic duration calculation

Added calculate_dynamic_duration() Method

This method calculates the exact time needed to display all stocks based on:

• Total scroll width of the content
• Display width
• Scroll speed and delay settings
• Configurable buffer time
• Min/max duration limits

Added get_dynamic_duration() Method

Returns the calculated dynamic duration for use by the display controller.

Updated display_stocks() Method

The method now calculates and stores the total scroll width and calls calculate_dynamic_duration() when creating the scrolling image.

3. Stock News Manager Updates (src/stock_news_manager.py)

Added Dynamic Duration Properties

# Dynamic duration settings
self.dynamic_duration_enabled = self.stock_news_config.get('dynamic_duration', True)
self.min_duration = self.stock_news_config.get('min_duration', 30)
self.max_duration = self.stock_news_config.get('max_duration', 300)
self.duration_buffer = self.stock_news_config.get('duration_buffer', 0.1)
self.dynamic_duration = 60  # Default duration in seconds
self.total_scroll_width = 0  # Track total width for dynamic duration calculation

Added calculate_dynamic_duration() Method

Similar to the stock manager, calculates duration based on content width and scroll settings.

Added get_dynamic_duration() Method

Returns the calculated dynamic duration for use by the display controller.

Updated display_news() Method

The method now calculates and stores the total scroll width and calls calculate_dynamic_duration() when creating the scrolling image.

4. Display Controller Updates (src/display_controller.py)

Updated get_current_duration() Method

Added dynamic duration handling for both stocks and stock_news modes:

# Handle dynamic duration for stocks
if mode_key == 'stocks' and self.stocks:
    try:
        dynamic_duration = self.stocks.get_dynamic_duration()
        # Only log if duration has changed or we haven't logged this duration yet
        if not hasattr(self, '_last_logged_duration') or self._last_logged_duration != dynamic_duration:
            logger.info(f"Using dynamic duration for stocks: {dynamic_duration} seconds")
            self._last_logged_duration = dynamic_duration
        return dynamic_duration
    except Exception as e:
        logger.error(f"Error getting dynamic duration for stocks: {e}")
        # Fall back to configured duration
        return self.display_durations.get(mode_key, 60)

# Handle dynamic duration for stock_news
if mode_key == 'stock_news' and self.news:
    try:
        dynamic_duration = self.news.get_dynamic_duration()
        # Only log if duration has changed or we haven't logged this duration yet
        if not hasattr(self, '_last_logged_duration') or self._last_logged_duration != dynamic_duration:
            logger.info(f"Using dynamic duration for stock_news: {dynamic_duration} seconds")
            self._last_logged_duration = dynamic_duration
        return dynamic_duration
    except Exception as e:
        logger.error(f"Error getting dynamic duration for stock_news: {e}")
        # Fall back to configured duration
        return self.display_durations.get(mode_key, 60)

How It Works

Dynamic Duration Calculation

The dynamic duration is calculated using the following formula:

1. Total Scroll Distance: display_width + total_scroll_width
2. Frames Needed: total_scroll_distance / scroll_speed
3. Base Time: frames_needed * scroll_delay
4. Buffer Time: base_time * duration_buffer
5. Final Duration: int(base_time + buffer_time)

The final duration is then clamped between min_duration and max_duration.

Integration with Display Controller

1. When the display controller needs to determine how long to show a particular mode, it calls get_current_duration()
2. For stocks and stock_news modes, it calls the respective manager's get_dynamic_duration() method
3. The manager returns the calculated duration based on the current content width
4. The display controller uses this duration to determine how long to display the content

Benefits

1. Consistent Display Time: Content is displayed for an appropriate amount of time based on its length
2. Configurable: Users can adjust min/max durations and buffer percentages
3. Fallback Support: If dynamic duration fails, it falls back to configured fixed durations
4. Performance: Duration is calculated once when content is created, not on every frame

Configuration Options

Dynamic Duration Settings

• dynamic_duration: Enable/disable dynamic duration calculation (default: true)
• min_duration: Minimum display duration in seconds (default: 30)
• max_duration: Maximum display duration in seconds (default: 300)
• duration_buffer: Buffer percentage to add for smooth cycling (default: 0.1 = 10%)

Example Configuration

{
    "dynamic_duration": true,
    "min_duration": 20,
    "max_duration": 180,
    "duration_buffer": 0.15
}

This would:

• Enable dynamic duration
• Set minimum display time to 20 seconds
• Set maximum display time to 3 minutes
• Add 15% buffer time for smooth cycling

Testing

The implementation has been tested to ensure:

• Configuration is properly loaded
• Dynamic duration calculation works correctly
• Display controller integration is functional
• Fallback behavior works when dynamic duration is disabled

Compatibility

This implementation follows the exact same pattern as the existing news_manager dynamic duration functionality, ensuring consistency across the codebase and making it easy to maintain and extend.