rpi_sense_hat_server/server.js

/**
 * Sense HAT 服务端
 */

require('dotenv').config()  // 读取系统环境变量

// HTTP状态测试路由
const app = require('express')()
app.get('/', (req, res) => res.sendStatus(200))

// 启动HTTP服务
const port = process.env.PORT || 3000
const host = process.env.HOST || 'localhost'
const server = app.listen(port, host, () => {
    console.log(`rpi sense hat server is running on port ${port}`)
})

// Sense HAT 初始化
const sensehat = {
    led: {
        /*
            require('sense-hat-led').sync中包含以下方法：
                sleep(n) 暂停 n 秒
                clear()  清除所有
                clear(rgb) or clear([r,g,b])  填充颜色
                setPixel(x,y,r,g,b) or setPixel(x,y,rgb)  设置一个点
                getPixel(x,y) 返回 [r,g,b]  获取一个点
                setPixels([[r,g,b]*64])
                getPixels() -> [[r,g,b]*64]
                flipH(redraw=true)  水平反转
                flipV(redraw=true)  垂直反转
                getter and setter rotation 默认为 0
                setRotation(r, redraw=true)  设置旋转，r 初始为 0，r 只能设置为 0/90/180/270
                loadImage(filePath, redraw=true)
                showLetter(character, textColour=[255,255,255], backColour=[0,0,0])
                showMessage(textString, scrollSpeed=0.1(秒), textColour=[255,255,255], backColour=[0,0,0])
                flashMessage(textString, speed=0.1(秒), textColour=[255,255,255], backColour=[0,0,0])

                # 未实现 # getter and setter lowLight 默认为 true
                # 未实现 # getter and setter gamma = Array of length 32 containing Integers between 0 and 31
                # 未实现 # gammaReset()  恢复默认 gamma
        */
        ...require('sense-hat-led').sync,
        get pixels() { return sensehat.led.getPixels() },
    },
}
sensehat.led.clear()
sensehat.led.setRotation(180)
sensehat.led.loadImage('images/heart.png')

// socketio 服务
const io = require('socket.io')(server, { cors: { origin: '*' } })
io.on('connection', (client) => {

    // 初始化客户端led矩阵
    io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })

    // 处理客户端请求
    client.on('action', ({ action, color, x, y, pixels, image, character, delay, speed, background, text }) => {

        x = Number(x)
        y = Number(y)
        delay = Number(delay || 200)
        speed = Number(speed || 0.1)
        character = character || ' '
        background = background || [0, 0, 0]

        switch (action) {

            case 'clear':
                color = color || [0, 0, 0]
                sensehat.led.clear(color)
                io.emit('action', { action: 'clear', color })
                break

            case 'setPixel':
                if (color == undefined) color = [255, 255, 255]
                sensehat.led.setPixel(x, y, color)
                io.emit('action', { action: 'setPixel', x, y, color })
                break

            case 'getPixel':
                color = sensehat.led.getPixel(x, y)
                client.emit('action', { action: 'setPixel', x, y, color })
                break

            case 'setPixels':
                pixels.forEach((color, i) => {
                    let x = i % 8
                    let y = Math.floor(i / 8)
                    sensehat.led.setPixel(x, y, color)
                })
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'getPixels':
                client.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'flipH':
                sensehat.led.flipH()
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'flipV':
                sensehat.led.flipV()
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'turnLeft':
                var heading_angle = (Number(sensehat.led.rotation) + 90) % 360
                sensehat.led.rotation = heading_angle
                sensehat.led.setRotation(heading_angle)
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'turnRight':
                var heading_angle = (Number(sensehat.led.rotation) + 360 - 90) % 360
                sensehat.led.rotation = heading_angle
                sensehat.led.setRotation(heading_angle)
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'loadImage':
                try {
                    sensehat.led.loadImage(`images/${image}.png`)
                    io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                } catch (error) {
                    console.error(error)
                }
                break

            case 'showLetter':
                if (color == undefined) color = [255, 255, 255]
                sensehat.led.showLetter(character, color, background)
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'showMessage':
                sensehat.led.showMessage(text, speed, color, background)
                sensehat.led.clear()
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'flashMessage':
                sensehat.led.flashMessage(text, speed, color, background)
                sensehat.led.clear()
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break

            case 'flash':
                if (color == undefined) color = [255, 255, 255]
                sensehat.led.clear(color)
                io.emit('action', { action: 'clear', color })
                setTimeout(() => {
                    sensehat.led.clear()
                    io.emit('action', { action: 'clear' })
                }, delay)
                break

            default:
                break
        }

    })
})