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

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const EventEmitter = require('events')
const CanvasRenderer = require('./screen_renderer')
const DEFAULT_FONT = '"DejaVu Sans Mono", "Liberation Mono", "Inconsolata", "Menlo", monospace'
/**
* Manages terminal screen layout and sizing
*/
module.exports = class ScreenLayout extends EventEmitter {
constructor () {
super()
this.canvas = document.createElement('canvas')
this.renderer = new CanvasRenderer(this.canvas)
this._window = {
width: 0,
height: 0,
devicePixelRatio: 1,
fontFamily: DEFAULT_FONT,
fontSize: 20,
padding: 6,
gridScaleX: 1.0,
gridScaleY: 1.2,
fitIntoWidth: 0,
fitIntoHeight: 0,
debug: false
}
// scaling caused by fitIntoWidth/fitIntoHeight
this._windowScale = 1
// actual padding, as it may be disabled by fullscreen mode etc.
this._padding = 0
// properties of this.window that require updating size and redrawing
this.windowState = {
width: 0,
height: 0,
devicePixelRatio: 0,
padding: 0,
gridScaleX: 0,
gridScaleY: 0,
fontFamily: '',
fontSize: 0,
fitIntoWidth: 0,
fitIntoHeight: 0
}
this.charSize = { width: 0, height: 0 }
const self = this
// make writing to window update size and draw
this.window = new Proxy(this._window, {
set (target, key, value) {
if (target[key] !== value) {
target[key] = value
self.scheduleSizeUpdate()
self.renderer.scheduleDraw(`window:${key}=${value}`)
self.emit(`update-window:${key}`, value)
}
return true
}
})
this.on('update-window:debug', debug => { this.renderer.debug = debug })
this.canvas.addEventListener('mousedown', e => this.emit('mousedown', e))
this.canvas.addEventListener('mousemove', e => this.emit('mousemove', e))
this.canvas.addEventListener('mouseup', e => this.emit('mouseup', e))
this.canvas.addEventListener('touchstart', e => this.emit('touchstart', e))
this.canvas.addEventListener('touchmove', e => this.emit('touchmove', e))
this.canvas.addEventListener('touchend', e => this.emit('touchend', e))
this.canvas.addEventListener('wheel', e => this.emit('wheel', e))
this.canvas.addEventListener('contextmenu', e => this.emit('contextmenu', e))
}
/**
* Schedule a size update in the next millisecond
*/
scheduleSizeUpdate () {
clearTimeout(this._scheduledSizeUpdate)
this._scheduledSizeUpdate = setTimeout(() => this.updateSize(), 1)
}
get backgroundImage () {
return this.canvas.style.backgroundImage
}
set backgroundImage (value) {
this.canvas.style.backgroundImage = value ? `url(${value})` : ''
if (this.renderer.backgroundImage !== !!value) {
this.renderer.backgroundImage = !!value
this.renderer.resetDrawn()
this.renderer.scheduleDraw('background-image')
}
}
get selectable () {
return this.canvas.classList.contains('selectable')
}
set selectable (selectable) {
if (selectable) this.canvas.classList.add('selectable')
else this.canvas.classList.remove('selectable')
}
/**
* Returns a CSS font string with the current font settings and the
* specified 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'
let fontFamily = this.window.fontFamily || ''
if (fontFamily.length > 0) fontFamily += ','
fontFamily += DEFAULT_FONT
return `${fontStyle} normal ${fontWeight} ${this.window.fontSize}px ${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()
x = x / this._windowScale - this._padding
y = y / this._windowScale - this._padding
x = Math.floor((x + (rounded ? cellSize.width / 2 : 0)) / cellSize.width)
y = Math.floor(y / cellSize.height)
x = Math.max(0, Math.min(this.window.width - 1, x))
y = Math.max(0, Math.min(this.window.height - 1, y))
return [x, y]
}
/**
* 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 => this._padding + (withScale ? v * this._windowScale : v))
}
/**
* Update 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
*/
updateCharSize () {
this.charSize = {
width: this.renderer.getCharWidthFor(this.getFont()),
height: this.window.fontSize
}
return this.charSize
}
/**
* 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 () {
if (!this.charSize.height && this.window.fontSize) this.updateCharSize()
return {
width: Math.ceil(this.charSize.width * this.window.gridScaleX),
height: Math.ceil(this.charSize.height * this.window.gridScaleY)
}
}
/**
* Updates the canvas size if it changed
*/
updateSize () {
// see below (this is just updating it)
this._window.devicePixelRatio = Math.ceil(this._windowScale * (window.devicePixelRatio || 1))
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,
padding
} = this.window
this.updateCharSize()
const cellSize = this.getCellSize()
// real height of the canvas element in pixels
let realWidth = width * cellSize.width
let realHeight = height * cellSize.height
let originalWidth = realWidth
if (fitIntoWidth && fitIntoHeight) {
let terminalAspect = realWidth / realHeight
let fitAspect = fitIntoWidth / fitIntoHeight
if (terminalAspect < fitAspect) {
// align heights
realHeight = fitIntoHeight - 2 * padding
realWidth = realHeight * terminalAspect
} else {
// align widths
realWidth = fitIntoWidth - 2 * padding
realHeight = realWidth / terminalAspect
}
}
// store new window scale
this._windowScale = realWidth / originalWidth
realWidth += 2 * padding
realHeight += 2 * padding
// store padding
this._padding = padding * (originalWidth / realWidth)
// the DPR must be rounded to a very nice value to prevent gaps between cells
let devicePixelRatio = this._window.devicePixelRatio = Math.ceil(this._windowScale * (window.devicePixelRatio || 1))
this.canvas.width = (width * cellSize.width + 2 * Math.round(this._padding)) * devicePixelRatio
this.canvas.style.width = `${realWidth}px`
this.canvas.height = (height * cellSize.height + 2 * Math.round(this._padding)) * devicePixelRatio
this.canvas.style.height = `${realHeight}px`
// the screen has been cleared (by changing canvas width)
this.renderer.resetDrawn()
this.renderer.render('update-size', this.serializeRenderData())
this.emit('size-update')
}
}
serializeRenderData () {
return {
padding: Math.round(this._padding),
devicePixelRatio: this.window.devicePixelRatio,
charSize: this.charSize,
cellSize: this.getCellSize(),
fonts: [
this.getFont(),
this.getFont({ weight: 'bold' }),
this.getFont({ style: 'italic' }),
this.getFont({ weight: 'bold', style: 'italic' })
]
}
}
render (reason, data) {
this.window.width = data.width
this.window.height = data.height
Object.assign(data, this.serializeRenderData())
this.renderer.render(reason, data)
}
}