yjs/examples/drawing/index.js
2017-12-06 19:20:52 -08:00

78 lines
1.9 KiB
JavaScript

/* globals Y, d3 */
let y = new Y({
connector: {
name: 'websockets-client',
url: 'http://127.0.0.1:1234',
room: 'drawing-example'
// maxBufferLength: 100
}
})
window.yDrawing = y
var drawing = y.share.drawing
var renderPath = d3.svg.line()
.x(function (d) { return d[0] })
.y(function (d) { return d[1] })
.interpolate('basis')
var svg = d3.select('#drawingCanvas')
.call(d3.behavior.drag()
.on('dragstart', dragstart)
.on('drag', drag)
.on('dragend', dragend))
// create line from a shared array object and update the line when the array changes
function drawLine (yarray) {
var line = svg.append('path').datum(yarray.toArray())
line.attr('d', renderPath)
yarray.observe(function (event) {
line.remove()
line = svg.append('path').datum(yarray.toArray())
line.attr('d', renderPath)
})
}
// call drawLine every time an array is appended
y.share.drawing.observe(function (event) {
event.changedKeys.forEach(function (key) {
let path = y.share.drawing.get(key)
if (path === undefined) {
svg.selectAll('path').remove()
} else {
drawLine(path)
}
})
})
// draw all existing content
for (var i = 0; i < drawing.length; i++) {
drawLine(drawing.get(i))
}
// clear canvas on request
document.querySelector('#clearDrawingCanvas').onclick = function () {
drawing.delete(0, drawing.length)
}
var sharedLine = null
function dragstart () {
drawing.insert(drawing.length, [Y.Array])
sharedLine = drawing.get(drawing.length - 1)
}
// After one dragged event is recognized, we ignore them for 33ms.
var ignoreDrag = null
function drag () {
if (sharedLine != null && ignoreDrag == null) {
ignoreDrag = window.setTimeout(function () {
ignoreDrag = null
}, 33)
sharedLine.push([d3.mouse(this)])
}
}
function dragend () {
sharedLine = null
window.clearTimeout(ignoreDrag)
ignoreDrag = null
}