opacity - good practice?

[nkhoi]

This code works but is it good practice to have it in on bar update?

protected override void OnBarUpdate()
...
double opacity = .25

if(trendUP)
{
BackBrush = BgColorUp;
Brush newBrush = BackBrush.Clone();
newBrush.Opacity = opacity;
newBrush.Freeze();
BackBrush = newBrush;
}

else if(trendDOWN)
{
BackBrush = BgColorDown;
Brush newBrush = BackBrush.Clone();
newBrush.Opacity = opacity;
newBrush.Freeze();
BackBrush = newBrush;
}

[NinjaTrader_ChelseaB]

Hello nkhoi,

This would be inefficient.

Instead of creating a new brush on every new bar, it would be more efficient to declare the variable of the brush within the scope of the class and initialize the brush once as the script starts in State.DataLoaded.

If you have two brushes, create two variables that are initialized in State.DataLoaded, and then switch between the variables in the logic of OnBarUpdate().

[nkhoi]

Hello nkhoi,

This would be inefficient.

Instead of creating a new brush on every new bar, it would be more efficient to declare the variable of the brush within the scope of the class and initialize the brush once as the script starts in State.DataLoaded.

If you have two brushes, create two variables that are initialized in State.DataLoaded, and then switch between the variables in the logic of OnBarUpdate().

I am not C programmer but I understand the point of not to call newBrush every bar. This is what I came up with. Will this be the same as what you mention?
-------------------------
private System.Windows.Media.Brush bgColorUp = Brushes.RoyalBlue;
private System.Windows.Media.Brush newBrushA, newBrushB, newBrushC, newBrushD ;
....
.....
protected override void OnBarUpdate()
{
//Add your custom indicator logic here.

if (newBrushA == null)
{
BackBrushAll = BgColorUp;
newBrushA = BackBrushAll.Clone();
newBrushA.Opacity = opacity;
newBrushA.Freeze();
}
.....
//
if (trendUP)
BackBrushAll = newBrushA;

[NinjaTrader_ChelseaB]

Hello nkhoi,

No, I am suggesting that you do the initialize or clone in OnStateChange when State is State.DataLoaded.

Below is a publicly available link to the help guide on OnStateChange().

https://ninjatrader.com/support/helpGuides/nt8/en-us/onstatechange.htm

private Brush newBrushA;

else if (State == State.DataLoaded)
{
newBrushA = BackBrush.Clone();
newBrushA.Opacity = opacity;
newBrushA.Freeze();
}

protected override void OnBarUpdate()
{
if (trendUP)
BackBrushAll = newBrushA;
}