How to tell the height of a Text object?

[ETFVoyageur]

I am using Draw.Text(). It draws text into a rectangular area. I need to know how tall that area will be so that I can position it properly (Y, YPixelOffset). How do I do that?

Prediction seems best -- can I predict the rectangle's height by knowing the font and how many lines my text will be?

Second best would be a sequence like the following -- is this, or anything else that solves the problem, doable?

• Inhibit refresh -- to prevent any possible flicker
• Draw.Text()
• Somehow force the text object object be rendered
• Inspect the Text object for its height (object.layoutRect.Height?)
• Position the Text object (object.Anchor.Price and object.YPixelOffset)
• Restore refresh

I''ve got to be overlooking some simple solution. Advice appreciated.

Thanks
EV

[ETFVoyageur]

Related question: how do I tell how many bars wide the text box is?

BTW: I know that object.layoutRect.Height is not accessible. I have found nothing else that contains the text box's geometry. Suggestions are welcome.

--EV

[NinjaTrader_Jesse]

Hello,

Thank you for the question.

Because DrawingTools specifically are locked to Price and Time/BarsAgo values finding the actual bounds of the rectangle will require using logic. Because you need the bounds of the text rectangle, in essence you would need to recreate part of the Text tool in your custom logic to calculate the Size of the Text object you create.

If you review the @Text.cs drawing tool file, you can see the exact logic being used currently to measure the string and set the text size etc.

I created a small sample to show how to get the 4 corners of a text object in the same way the @Text tool measures.

Please note this does not account for the border of the object and is only based off of the texts Anchor point. Additionally this specifically references Panel 0 of the chart, to test this would need to be overlaid on the primary panel. Finally this does require chartScale because you are dealing with Heights, the Scale is important in order to find the Correct Y values depending on the current scale.

As far as getting a number of bars the text tool spans, you could look into using the X values you get for the Left and the Right to get SlotIndexes. With these Indexes, you could use math to get the total number between the two returned values.

private Text myText;
private string myTextContent = "Testing";

protected override void OnBarUpdate()
{

	if (State == State.Historical) return;
	myText = Draw.Text(this, "test", true, myTextContent, 0, Close[0], 0, Brushes.Red, new SimpleFont("Arial", 12), TextAlignment.Center, Brushes.Transparent, Brushes.Black, 45);
}

protected override void OnRender(ChartControl chartControl, ChartScale chartScale)
{
	if (myText != null)
	{
		SharpDX.DirectWrite.TextFormat textFormat = myText.Font.ToDirectWriteTextFormat();
		SharpDX.DirectWrite.TextLayout layout = new SharpDX.DirectWrite.TextLayout(Core.Globals.DirectWriteFactory, myTextContent, textFormat, chartControl.ChartPanels[0].W, textFormat.FontSize);
		float startX = chartControl.GetXByTime(myText.Anchor.Time);
		float startY = chartScale.GetYByValue(myText.Anchor.Price);
		Print(startX + " " + startY);

		float yTop = startY - layout.Metrics.Height / 2;
		float yBottom = startY + layout.Metrics.Height / 2;
		float xLeft = startX - layout.Metrics.Width / 2;
		float xRight = startX + layout.Metrics.Width / 2;

		RenderTarget.FillEllipse(new SharpDX.Direct2D1.Ellipse(new SharpDX.Vector2(xLeft, yTop), 8, 8), Brushes.Blue.ToDxBrush(RenderTarget));
		RenderTarget.FillEllipse(new SharpDX.Direct2D1.Ellipse(new SharpDX.Vector2(xLeft, yBottom), 8, 8), Brushes.Blue.ToDxBrush(RenderTarget));
		RenderTarget.FillEllipse(new SharpDX.Direct2D1.Ellipse(new SharpDX.Vector2(xRight, yTop), 8, 8), Brushes.Blue.ToDxBrush(RenderTarget));
		RenderTarget.FillEllipse(new SharpDX.Direct2D1.Ellipse(new SharpDX.Vector2(xRight, yBottom), 8, 8), Brushes.Blue.ToDxBrush(RenderTarget));
	}

	base.OnRender(chartControl, chartScale);
}

I look forward to being of further assistance.

[koganam]

I am using Draw.Text(). It draws text into a rectangular area. I need to know how tall that area will be so that I can position it properly (Y, YPixelOffset). How do I do that?

Prediction seems best -- can I predict the rectangle's height by knowing the font and how many lines my text will be?

Second best would be a sequence like the following -- is this, or anything else that solves the problem, doable?

• Inhibit refresh -- to prevent any possible flicker
• Draw.Text()
• Somehow force the text object object be rendered
• Inspect the Text object for its height (object.layoutRect.Height?)
• Position the Text object (object.Anchor.Price and object.YPixelOffset)
• Restore refresh

I''ve got to be overlooking some simple solution. Advice appreciated.

Thanks
EV

From some old threads of which you were a part:

ref: http://ninjatrader.com/support/forum...ad.php?t=77478

http://ninjatrader.com/support/forum/showthread.php?t=77140

[ETFVoyageur]

Jesse,

Thanks for your help. The two lines that create the textFormat and layout objects are just what I need. Together with the magic padding constant (10.5) from Text.cs it works fine.

That said, I am not happy to have to hard-code an internal magic constant -- that makes for fragile code, because that constant could easily change in a future release. There really needs to be a fully-supported way to get the geometry of the area that will be used by a call to Draw.Text()

Anyway, thanks again. My code, fragile or not, is working fine now. The text is getting positioned exactly where I want it.

--EV

Note: for anyone who is not sure what the problem is: the basic calls will position the center of the text area just fine. You an set the Y value and a pixel offset to do what you need to do. What you cannot do without the information this thread provides is to position the top or bottom of the text area accurately, because without knowing the area's height you do not know what pixel offset to specify.