How modify DrawObject by by their TAG as RemoveDrawObject?

[aekzof]

the purpose of the strategy is to
1. draw an object at each new bar
2. then delete these objects except the last 5
3. Modify the opacity and color of the 4 objects
we do nothing for the draw object on CurrentBar


in this link https://ninjatrader.com/fr/support/h...rawobjects.htm
there is this line which allows to modify the color of the object in black
globalLine.Stroke.Brush = Brushes.Black;

my question
is there a solution that allows to modify the opavity, color, width... of the object by its TAG like RemoveDrawObject("tag_" + (CurrentBar-5));

Thanks in advance

protected override void OnBarUpdate()
{
if (BarsInProgress != 0)
return;

if (CurrentBars[0] < 1)
return;

Draw.VerticalLine(this, "tag_" + Convert.ToString(CurrentBars[0]), 0, Brushes.Lime, DashStyleHelper.Solid, 2);

RemoveDrawObject("tag_" + (CurrentBar-5));

foreach (DrawingTool draw in DrawObjects.ToList())
{
if (draw is DrawingTools.Line)
{
DrawingTools.Line globalLine = draw as DrawingTools.Line;

globalLine.Stroke.Brush = Brushes.Black;

}

}
}

[NinjaTrader_Kate]

Hello aekzof,

Thank you for your reply.

If I'm understanding correctly, you always want vertical lines on the last 5 bars. It would be simpler to just redraw the same line, and for the lines you wish to be a different color with a different opacity, a custom brush needs to be constructed to control Opacity (alpha value). Instead of using one of the pre-built brushes (Brushes.Red, Brushes.Blue, etc), construct your own SolidColorBrush employing the Color.FromArgb() method, the first value is the "alpha":

https://ninjatrader.com/support/help...gcustombrushes

myBrush = new SolidColorBrush(Color.FromArgb(123, 0, 0, 0)); // create a 50% opaque black brush
myBrush.Freeze();

I'm attaching a very simple example script that demonstrates.

Please let us know if we may be of further assistance to you.

[aekzof]

Thank you for your reply .
Unfortunately that's not what I want.
to fully understand the question I am attaching a script .

https://ninjatrader.com/support/forum/filedata/fetch?filedataid=74169

in this stratefy a vertical line will be drawn each bar.

what i want is to
1. delete all lines except the last 5 lines
2. change the color and opacity of the 4 lines from the left
so we don't take line[0] draw on currentbar

thanks again

[aekzof]

RemovePreviousLines_NT8.zip

[NinjaTrader_Kate]

Hello aekzof,

Thank you for your reply.

You wouldn't be able to change color and opacity of prior lines using lines drawn in the Strategy Builder as opacity would need to be applied using the manually coded approach seen in my prior reply.

The example you have supplied is unclear - can you clarify how what the desired behavior you're describing is different from the example I supplied when the indicator is applied to a chart?

Thanks in advance; I look forward to assisting you further.

[aekzof]

Hello
Sorry for my late response
I found a solution I don't know if it's good or not and if there is a more effective solution.

my solution is to draw the same line twice on each new bar with a different color and tag
then for the lines with 1st color we delete all the lines except Line0
for lines with 2nd color we delete everything except the last 4 lines
what we have left. 2 lines on bar[0] with the 1st color dominating
and 3 lines on bar[1],bar[2],bar[3] with the 2nd color
after we change the opacity of these 3 lines



you can try my script it works very well and that's what I want.

protected override void OnBarUpdate()
{
if (BarsInProgress != 0)
return;

if (CurrentBars[0] < 5)
return;

if (IsFirstTickOfBar)
{

var someTag = "sometag_" + Convert.ToString(CurrentBars[0]);
var oldTag = "oldtag_" + Convert.ToString(CurrentBars[0]);


//draw two lines on each new bar (the difference just the color and the name for later use)

Draw.VerticalLine(this, someTag, 0, Brushes.Blue, DashStyleHelper.Solid, 3);
NinjaTrader.NinjaScript.DrawingTools.Line myOldLine = Draw.VerticalLine(this, oldTag, 0, Brushes.Yellow, DashStyleHelper.Dot, 3);

RemoveDrawObject("sometag_" + (CurrentBar - 1)); //delete all Blue lines except the last on currentbar
RemoveDrawObject("oldtag_" + (CurrentBar - 4)); //delete all Yellow lines except the last 4

myOldLine.Stroke.Opacity = 25;

}
}

indeed what I need is like a trendline
with each new trendline
the old trendline takes another color with less opacity.
and the same for a broken resistor
it takes another color and we reduce the opacity
then we control the number of old trendlines or broken resistances to display
Thanks

[NinjaTrader_Kate]

Hello aekzof,

Thank you for your reply.

Drawing multiple lines on every bar only to immediately remove them when you only want lines drawn on the most recent 5 bars would impact performance considerably more than simply drawing 5 lines that move to new bars as they form. In fact, the only difference I can see between my example above and your code would be my example has one more line and different colors. You would get the same results with considerably less performance impact going the route illustrated above.

Please let us know if we may be of further assistance to you.

[aekzof]

Hello
Your answer is based on a question that I worded incorrectly.
because I simplified my question by this example to arrive at a solution. it is not necessarily that the lines are drawn for each new bar.
let's take an example trendline included with ninjatrader there is always the history of trendlines that take place but with different opacity and color from the current trendline


so it's the same principle
it's not a professional script but it does the trick.

thank you for your help and see you in my next questions