ESPTerm web interface submodule, separated to make testing and development easier
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espterm-front-end/js/term/screen.js

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const EventEmitter = require('events')
const $ = require('../lib/chibi')
const { mk, qs } = require('../utils')
const notify = require('../notif')
const ScreenParser = require('./screen_parser')
const ScreenRenderer = require('./screen_renderer')
module.exports = class TermScreen extends EventEmitter {
constructor () {
super()
this.canvas = mk('canvas')
this.ctx = this.canvas.getContext('2d')
this.parser = new ScreenParser(this)
this.renderer = new ScreenRenderer(this)
// debug screen handle
this._debug = null
if ('AudioContext' in window || 'webkitAudioContext' in window) {
this.audioCtx = new (window.AudioContext || window.webkitAudioContext)()
} else {
console.warn('No AudioContext!')
}
// dummy. Handle for Input
this.input = new Proxy({}, {
get () {
return () => console.warn('TermScreen#input not set!')
}
})
// dummy. Handle for Conn
this.conn = new Proxy({}, {
get () {
return () => console.warn('TermScreen#conn not set!')
},
set (a, b) {
return () => console.warn('TermScreen#conn not set!')
}
})
this.cursor = {
x: 0,
y: 0,
blinking: true,
visible: true,
hanging: false,
style: 'block'
}
this._window = {
width: 0,
height: 0,
devicePixelRatio: 1,
fontFamily: '"DejaVu Sans Mono", "Liberation Mono", "Inconsolata", "Menlo", monospace',
fontSize: 20,
gridScaleX: 1.0,
gridScaleY: 1.2,
fitIntoWidth: 0,
fitIntoHeight: 0,
debug: false,
graphics: 0,
statusScreen: null
}
// scaling caused by fitIntoWidth/fitIntoHeight
this._windowScale = 1
// properties of this.window that require updating size and redrawing
this.windowState = {
width: 0,
height: 0,
devicePixelRatio: 0,
gridScaleX: 0,
gridScaleY: 0,
fontFamily: '',
fontSize: 0,
fitIntoWidth: 0,
fitIntoHeight: 0
}
// current selection
this.selection = {
// when false, this will prevent selection in favor of mouse events,
// though alt can be held to override it
selectable: true,
// selection start and end (x, y) tuples
start: [0, 0],
end: [0, 0]
}
// mouse features
this.mouseMode = { clicks: false, movement: false }
// make writing to window update size and draw
const self = this
this.window = new Proxy(this._window, {
set (target, key, value, receiver) {
target[key] = value
self.scheduleSizeUpdate()
self.renderer.scheduleDraw(`window:${key}=${value}`)
self.emit(`update-window:${key}`, value)
return true
}
})
this.bracketedPaste = false
this.blinkingCellCount = 0
this.reverseVideo = false
this.screen = []
this.screenFG = []
this.screenBG = []
this.screenAttrs = []
let selecting = false
let selectStart = (x, y) => {
if (selecting) return
selecting = true
this.selection.start = this.selection.end = this.screenToGrid(x, y, true)
this.renderer.scheduleDraw('select-start')
}
let selectMove = (x, y) => {
if (!selecting) return
this.selection.end = this.screenToGrid(x, y, true)
this.renderer.scheduleDraw('select-move')
}
let selectEnd = (x, y) => {
if (!selecting) return
selecting = false
this.selection.end = this.screenToGrid(x, y, true)
this.renderer.scheduleDraw('select-end')
Object.assign(this.selection, this.getNormalizedSelection())
}
// bind event listeners
this.canvas.addEventListener('mousedown', e => {
if ((this.selection.selectable || e.altKey) && e.button === 0) {
selectStart(e.offsetX, e.offsetY)
} else {
this.input.onMouseDown(...this.screenToGrid(e.offsetX, e.offsetY),
e.button + 1)
}
})
window.addEventListener('mousemove', e => {
selectMove(e.offsetX, e.offsetY)
})
window.addEventListener('mouseup', e => {
selectEnd(e.offsetX, e.offsetY)
})
// touch event listeners
let touchPosition = null
let touchDownTime = 0
let touchSelectMinTime = 500
let touchDidMove = false
let getTouchPositionOffset = touch => {
let rect = this.canvas.getBoundingClientRect()
return [touch.clientX - rect.left, touch.clientY - rect.top]
}
this.canvas.addEventListener('touchstart', e => {
touchPosition = getTouchPositionOffset(e.touches[0])
touchDidMove = false
touchDownTime = Date.now()
}, { passive: true })
this.canvas.addEventListener('touchmove', e => {
touchPosition = getTouchPositionOffset(e.touches[0])
if (!selecting && touchDidMove === false) {
if (touchDownTime < Date.now() - touchSelectMinTime) {
selectStart(...touchPosition)
}
} else if (selecting) {
e.preventDefault()
selectMove(...touchPosition)
}
touchDidMove = true
})
this.canvas.addEventListener('touchend', e => {
if (e.touches[0]) {
touchPosition = getTouchPositionOffset(e.touches[0])
}
if (selecting) {
e.preventDefault()
selectEnd(...touchPosition)
// selection ended; show touch select menu
let touchSelectMenu = qs('#touch-select-menu')
touchSelectMenu.classList.add('open')
let rect = touchSelectMenu.getBoundingClientRect()
// use middle position for x and one line above for y
let selectionPos = this.gridToScreen(
(this.selection.start[0] + this.selection.end[0]) / 2,
this.selection.start[1] - 1
)
selectionPos[0] -= rect.width / 2
selectionPos[1] -= rect.height / 2
touchSelectMenu.style.transform = `translate(${selectionPos[0]}px, ${
selectionPos[1]}px)`
}
if (!touchDidMove) {
this.emit('tap', Object.assign(e, {
x: touchPosition[0],
y: touchPosition[1]
}))
}
touchPosition = null
})
this.on('tap', e => {
if (this.selection.start[0] !== this.selection.end[0] ||
this.selection.start[1] !== this.selection.end[1]) {
// selection is not empty
// reset selection
this.selection.start = this.selection.end = [0, 0]
qs('#touch-select-menu').classList.remove('open')
this.renderer.scheduleDraw('select-reset')
} else {
e.preventDefault()
this.emit('open-soft-keyboard')
}
})
$.ready(() => {
let copyButton = qs('#touch-select-copy-btn')
if (copyButton) {
copyButton.addEventListener('click', () => {
this.copySelectionToClipboard()
})
}
})
this.canvas.addEventListener('mousemove', e => {
if (!selecting) {
this.input.onMouseMove(...this.screenToGrid(e.offsetX, e.offsetY))
}
})
this.canvas.addEventListener('mouseup', e => {
if (!selecting) {
this.input.onMouseUp(...this.screenToGrid(e.offsetX, e.offsetY),
e.button + 1)
}
})
this.canvas.addEventListener('wheel', e => {
if (this.mouseMode.clicks) {
this.input.onMouseWheel(...this.screenToGrid(e.offsetX, e.offsetY),
e.deltaY > 0 ? 1 : -1)
// prevent page scrolling
e.preventDefault()
}
})
this.canvas.addEventListener('contextmenu', e => {
if (this.mouseMode.clicks) {
// prevent mouse keys getting stuck
e.preventDefault()
}
selectEnd(e.offsetX, e.offsetY)
})
}
/**
* Schedule a size update in the next millisecond
*/
scheduleSizeUpdate () {
clearTimeout(this._scheduledSizeUpdate)
this._scheduledSizeUpdate = setTimeout(() => this.updateSize(), 1)
}
/**
* Returns a CSS font string with this TermScreen's font settings and the
* font modifiers.
* @param {Object} modifiers
* @param {string} [modifiers.style] - the font style
* @param {string} [modifiers.weight] - the font weight
* @returns {string} a CSS font string
*/
getFont (modifiers = {}) {
let fontStyle = modifiers.style || 'normal'
let fontWeight = modifiers.weight || 'normal'
return `${fontStyle} normal ${fontWeight} ${this.window.fontSize}px ${this.window.fontFamily}`
}
/**
* Converts screen coordinates to grid coordinates.
* @param {number} x - x in pixels
* @param {number} y - y in pixels
* @param {boolean} rounded - whether to round the coord, used for select highlighting
* @returns {number[]} a tuple of (x, y) in cells
*/
screenToGrid (x, y, rounded = false) {
let cellSize = this.getCellSize()
return [
Math.floor((x + (rounded ? cellSize.width / 2 : 0)) / cellSize.width),
Math.floor(y / cellSize.height)
]
}
/**
* Converts grid coordinates to screen coordinates.
* @param {number} x - x in cells
* @param {number} y - y in cells
* @param {boolean} [withScale] - when true, will apply window scale
* @returns {number[]} a tuple of (x, y) in pixels
*/
gridToScreen (x, y, withScale = false) {
let cellSize = this.getCellSize()
return [x * cellSize.width, y * cellSize.height].map(v => withScale ? v * this._windowScale : v)
}
/**
* The character size, used for calculating the cell size. The space character
* is used for measuring.
* @returns {Object} the character size with `width` and `height` in pixels
*/
getCharSize () {
this.ctx.font = this.getFont()
return {
width: Math.floor(this.ctx.measureText(' ').width),
height: this.window.fontSize
}
}
/**
* The cell size, which is the character size multiplied by the grid scale.
* @returns {Object} the cell size with `width` and `height` in pixels
*/
getCellSize () {
let charSize = this.getCharSize()
return {
width: Math.ceil(charSize.width * this.window.gridScaleX),
height: Math.ceil(charSize.height * this.window.gridScaleY)
}
}
/**
* Updates the canvas size if it changed
*/
updateSize () {
// see below (this is just updating it)
this._window.devicePixelRatio = Math.round(this._windowScale * (window.devicePixelRatio || 1) * 2) / 2
let didChange = false
for (let key in this.windowState) {
if (this.windowState.hasOwnProperty(key) && this.windowState[key] !== this.window[key]) {
didChange = true
this.windowState[key] = this.window[key]
}
}
if (didChange) {
const {
width,
height,
fitIntoWidth,
fitIntoHeight
} = this.window
const cellSize = this.getCellSize()
// real height of the canvas element in pixels
let realWidth = width * cellSize.width
let realHeight = height * cellSize.height
if (fitIntoWidth && fitIntoHeight) {
let terminalAspect = realWidth / realHeight
let fitAspect = fitIntoWidth / fitIntoHeight
if (terminalAspect < fitAspect) {
// align heights
realHeight = fitIntoHeight
realWidth = realHeight * terminalAspect
} else {
// align widths
realWidth = fitIntoWidth
realHeight = realWidth / terminalAspect
}
} else if (fitIntoWidth) {
realHeight = fitIntoWidth / (realWidth / realHeight)
realWidth = fitIntoWidth
} else if (fitIntoHeight) {
realWidth = fitIntoHeight * (realWidth / realHeight)
realHeight = fitIntoHeight
}
// store new window scale
this._windowScale = realWidth / (width * cellSize.width)
// the DPR must be rounded to a very nice value to prevent gaps between cells
let devicePixelRatio = this._window.devicePixelRatio = Math.round(this._windowScale * (window.devicePixelRatio || 1) * 2) / 2
this.canvas.width = width * devicePixelRatio * cellSize.width
this.canvas.style.width = `${realWidth}px`
this.canvas.height = height * devicePixelRatio * cellSize.height
this.canvas.style.height = `${realHeight}px`
// the screen has been cleared (by changing canvas width)
this.renderer.resetDrawn()
// draw immediately; the canvas shouldn't flash
this.renderer.draw('update-size')
}
}
/**
* Returns a normalized version of the current selection, such that `start`
* is always before `end`.
* @returns {Object} the normalized selection, with `start` and `end`
*/
getNormalizedSelection () {
let { start, end } = this.selection
// if the start line is after the end line, or if they're both on the same
// line but the start column comes after the end column, swap
if (start[1] > end[1] || (start[1] === end[1] && start[0] > end[0])) {
[start, end] = [end, start]
}
return { start, end }
}
/**
* Returns whether or not a given cell is in the current selection.
* @param {number} col - the column (x)
* @param {number} line - the line (y)
* @returns {boolean}
*/
isInSelection (col, line) {
let { start, end } = this.getNormalizedSelection()
let colAfterStart = start[0] <= col
let colBeforeEnd = col < end[0]
let onStartLine = line === start[1]
let onEndLine = line === end[1]
if (onStartLine && onEndLine) return colAfterStart && colBeforeEnd
else if (onStartLine) return colAfterStart
else if (onEndLine) return colBeforeEnd
else return start[1] < line && line < end[1]
}
/**
* Sweeps for selected cells and joins them in a multiline string.
* @returns {string} the selection
*/
getSelectedText () {
const screenLength = this.window.width * this.window.height
let lines = []
let previousLineIndex = -1
for (let cell = 0; cell < screenLength; cell++) {
let x = cell % this.window.width
let y = Math.floor(cell / this.window.width)
if (this.isInSelection(x, y)) {
if (previousLineIndex !== y) {
previousLineIndex = y
lines.push('')
}
lines[lines.length - 1] += this.screen[cell]
}
}
return lines.join('\n')
}
/**
* Copies the selection to clipboard and creates a notification balloon.
*/
copySelectionToClipboard () {
let selectedText = this.getSelectedText()
// don't copy anything if nothing is selected
if (!selectedText) return
let textarea = mk('textarea')
document.body.appendChild(textarea)
textarea.value = selectedText
textarea.select()
if (document.execCommand('copy')) {
notify.show('Copied to clipboard')
} else {
notify.show('Failed to copy')
}
document.body.removeChild(textarea)
}
/**
* Shows an actual notification (if possible) or a notification balloon.
* @param {string} text - the notification content
*/
showNotification (text) {
console.info(`Notification: ${text}`)
if (window.Notification && window.Notification.permission === 'granted') {
let notification = new window.Notification('ESPTerm', {
body: text
})
notification.addEventListener('click', () => window.focus())
} else {
if (window.Notification && window.Notification.permission !== 'denied') {
window.Notification.requestPermission()
} else {
// Fallback using the built-in notification balloon
notify.show(text)
}
}
}
/**
* Creates a beep sound.
*/
beep () {
const audioCtx = this.audioCtx
if (!audioCtx) return
// prevent screeching
if (this._lastBeep && this._lastBeep > Date.now() - 50) return
this._lastBeep = Date.now()
if (!this._convolver) {
this._convolver = audioCtx.createConvolver()
let impulseLength = audioCtx.sampleRate * 0.8
let impulse = audioCtx.createBuffer(2, impulseLength, audioCtx.sampleRate)
for (let i = 0; i < impulseLength; i++) {
impulse.getChannelData(0)[i] = (1 - i / impulseLength) ** (7 + Math.random())
impulse.getChannelData(1)[i] = (1 - i / impulseLength) ** (7 + Math.random())
}
this._convolver.buffer = impulse
this._convolver.connect(audioCtx.destination)
}
// main beep
const mainOsc = audioCtx.createOscillator()
const mainGain = audioCtx.createGain()
mainOsc.connect(mainGain)
mainGain.gain.value = 4
mainOsc.frequency.value = 750
mainOsc.type = 'sine'
// surrogate beep (making it sound like 'oops')
const surrOsc = audioCtx.createOscillator()
const surrGain = audioCtx.createGain()
surrOsc.connect(surrGain)
surrGain.gain.value = 2
surrOsc.frequency.value = 400
surrOsc.type = 'sine'
mainGain.connect(this._convolver)
surrGain.connect(this._convolver)
let startTime = audioCtx.currentTime
mainOsc.start()
mainOsc.stop(startTime + 0.5)
surrOsc.start(startTime + 0.05)
surrOsc.stop(startTime + 0.8)
let loop = function () {
if (audioCtx.currentTime < startTime + 0.8) window.requestAnimationFrame(loop)
mainGain.gain.value *= 0.8
surrGain.gain.value *= 0.8
}
loop()
}
load (...args) {
this.parser.load(...args)
}
}