Flashlight.js

// Import required modules for display and keyboard functionality
const display = require("display");
const keyboard = require("keyboard");

// Define color palette for the flashlight
// Colors are defined using RGB values (red, green, blue)
const colours = [
    display.color(0, 0, 0),       // black
    display.color(127, 127, 127), // grey
    display.color(255, 255, 255), // white
    display.color(255, 0, 0),     // red
    display.color(255, 165, 0),   // orange
    display.color(255, 255, 0),   // yellow
    display.color(0, 255, 0),     // green
    display.color(0, 255, 255),   // cyan
    display.color(0, 0, 255),     // blue
    display.color(75, 0, 130),    // indigo
    display.color(138, 43, 226),  // violet
    display.color(255, 0, 255)    // magenta
];

// Application state variables
var currentColour = 2;  // Start with white color (index 2)
var lightOn = false;    // Flashlight starts in off state
var exitApp = false;    // Controls main application loop

// Get display dimensions for responsive layout
const displayWidth = display.width();
const displayHeight = display.height();
// Scale font size based on display width (larger screens get bigger fonts)
const fontScale = (displayWidth > 300 ? 1 : 0);

// Show the initial standby screen
displayStandby();

/**
 * Displays the standby/welcome screen with instructions
 * Shows app title, controls, and author credit
 */
function displayStandby() {
    // Clear screen with black background
    display.fill(colours[0]);
    // Center-align all text
    display.setTextAlign('center', 'middle');

    // Display app title in blue
    display.setTextSize(2 + fontScale);
    display.setTextColor(BRUCE_PRICOLOR);
    display.drawText("Flashlight", displayWidth / 2, 10 + fontScale * 5);

    // Display control instructions in grey
    display.setTextSize(1 + fontScale);
    display.setTextColor(colours[1]);
    display.drawText("Select: On/Off", displayWidth / 2, displayHeight / 6 * 2);
    display.drawText("Next/Prev: Change Colours", displayWidth / 2, displayHeight / 6 * 3);
    display.drawText("Exit: Close Flashlight", displayWidth / 2, displayHeight / 6 * 4);

    // Display author credit in white at bottom
    display.setTextSize(1 + fontScale);
    display.setTextColor(colours[2]);
    display.drawText("By github.com/emericklaw", displayWidth / 2, displayHeight - 5 - fontScale * 5);
}

// Main application loop - continues until exitApp becomes true
while (!exitApp) {
    // Check for exit button press (ESC key)
    if (getEscPress()) {
        exitApp = true;
        break;
    }
    
    // Handle Select button press - toggle flashlight on/off
    if (keyboard.getSelPress()) {
        lightOn = !lightOn;  // Toggle the light state
        if (lightOn) {
            // Turn on flashlight with current color
            display.fill(colours[currentColour]);
        } else {
            // Turn off flashlight and show standby screen
            displayStandby();
        }
    }
    
    // Handle Previous button press - cycle to previous color or turn on light
    if (keyboard.getPrevPress()) {
        if (!lightOn) {
            // If light is off, turn it on with current color
            lightOn = true;
        } else {
            // If light is on, cycle to previous color
            currentColour--;
            // Wrap around to last color if we go below index 1 (skip black at index 0)
            if (currentColour < 1) {
                currentColour = colours.length - 1;
            }
        }
        // Update display with new color
        display.fill(colours[currentColour]);
    }
    
    // Handle Next button press - cycle to next color or turn on light
    if (keyboard.getNextPress()) {
        if (!lightOn) {
            // If light is off, turn it on with current color
            lightOn = true;
        } else {
            // If light is on, cycle to next color
            currentColour++;
            // Wrap around to first usable color if we exceed array bounds
            if (currentColour > colours.length - 1) {
                currentColour = 1;  // Skip black (index 0), start from grey (index 1)
            }
        }
        // Update display with new color
        display.fill(colours[currentColour]);
    }
    
    // Small delay to prevent excessive CPU usage and button bouncing
    delay(50);
}