initial diagonal work (unfinished)

src/charts/chart.js

@@ -27,6 +27,7 @@ function changeSymbol(symbol) {
     lastSymbolChangedArgs = info
     symbolChangedCbs.forEach((cb)=>cb(info))
     co.selectedSymbol = info
+    co.meanRange = chartMeanRange()
 }
 
 
@@ -364,3 +365,21 @@ export function deleteShapeId(id) {
     // console.log('removing entity', id)
     chart.removeEntity(id)
 }
+
+function chartMeanRange() {
+    let range = 0
+    const series = chart.getSeries()
+    const bars = series.data().bars();
+    const final = Math.max(bars.size() - 50, 0)
+    let count = 0
+    for (let barIndex = bars.size() - 1; barIndex >= final; barIndex--) {
+        count++
+        const [_time, _open, high, low, _close, _volume, _ms] = bars.valueAt(barIndex)
+        range += (high - low)
+    }
+    if (count > 0)
+        range /= count
+    else
+        range = 1
+    return range
+}