neale/vail
neale
/
vail
mirror of https://github.com/nealey/vail.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Chart remembers initial value on left

This commit is contained in:
Neale Pickett 2022-04-24 13:28:20 -07:00
parent 54668eb0f1
commit 2290c2ff02
1 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
static/chart.mjs
View File

@ -20,8 +20,6 @@ class HistoryChart {
this.duration = duration
this.data = []
this.max = 1
this.min = 0
// One canvas pixel = 20ms
canvas.width = duration / (20 * Millisecond)
@ -52,7 +50,8 @@ class HistoryChart {
let earliest = now - this.duration
this.data.push([when, value])
while (this.data[0][0] < earliest) {
// Leave one old datapoint so we know the value when the window opens
while ((this.data.length > 1) && (this.data[1][0] < earliest)) {
this.data.shift()
}
@ -63,16 +62,17 @@ class HistoryChart {
let now = Date.now()
let earliest = now - this.duration
let xScale = this.canvas.width / this.duration
let yScale = this.canvas.height * 0.95
let y = 0
this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height)
this.ctx.moveTo(0, y)
this.ctx.moveTo(0, 0)
this.ctx.beginPath()
for (let point of this.data) {
let x = (point[0] - earliest) * xScale
this.ctx.lineTo(x, y)
y = point[1] * this.canvas.height
y = point[1] * yScale
this.ctx.lineTo(x, y)
}
this.ctx.lineTo(this.canvas.width, y)