rpi_sense_hat_server/server.js

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

// HTTP 请求路由
const app = require('express')()
app.get('/', (req, res) => res.sendStatus(200))

// 服务器启动
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 at http://${host}:${port}`)
})

// Sense HAT 全局数据 及 初始化
const R = [255, 0, 0]
const G = [0, 255, 0]
const B = [0, 0, 255]
const Y = [255, 255, 0]
const P = [255, 0, 255]
const C = [0, 255, 255]
const O = [255, 255, 255]
const _ = [0, 0, 0]
const sensehat = {
    led: {
        ...require('sense-hat-led').sync,
        /*
            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
        */
        get pixels() { return sensehat.led.getPixels() },
    },
}
sensehat.led.clear()
sensehat.led.loadImage('images/heart.png')

// socketio 服务
const io = require('socket.io')(server, { cors: { origin: '*' } })
io.on('connection', (client) => {
    io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
    client.on('action', ({ action, x, y, color, pixels, delay, image, character, speed, background, text }) => {
        x = Number(x), y = Number(y), delay = Number(delay) | 200, speed = Number(speed) | 0.2
        if (character == undefined) character = ' '
        if (background == undefined) background = [0, 0, 0]
        switch (action) {
            case 'clear':
                if (color == undefined) color = [0, 0, 0]
                sensehat.led.clear(color)
                io.emit('action', { action: 'clear', color })
                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
            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':
                for (let i = 0; i < pixels.length; i++) {
                    var color = pixels[i]
                    var x = i % 8
                    var y = Math.floor(i / 8)
                    sensehat.led.setPixel(x, y, color)
                }
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break
            case 'getPixels':
                io.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':
                if (color == undefined) color = [255, 255, 255]
                sensehat.led.showMessage(text, speed, color, background)
                io.emit('action', { action: 'setPixels', pixels: sensehat.led.pixels })
                break
            default:
                break
        }

    })
})