Is there a way to get graphic text to scale in ArcMap? - gis

Question

I'm using this code to create text in ArcMap. But I can't seem to get it to scale like annotation text when you zoom in.
Does anyone know how to do this?
//'First setup a color. We'll use RGB red
IRgbColor pRGBcolor = new RgbColor();
pRGBcolor.Blue = 0;
pRGBcolor.Red = 255;
pRGBcolor.Green = 0;
//'Next, cocreate a new TextElement
ITextElement pTextElement = new TextElementClass();
//'Query Interface (QI) to an IElement pointer and set
//'the geometry that was passed in
IElement pElement = pTextElement as IElement;
pElement.Geometry = Point;
//'Next, setup a font
stdole.IFontDisp pFontDisp = new stdole.StdFont() as stdole.IFontDisp;
pFontDisp.Name = "Arial";
pFontDisp.Bold = true;
//'Next, setup a TextSymbol that the TextElement will draw with
ITextSymbol pTextSymbol = new ESRI.ArcGIS.Display.TextSymbolClass();
pTextSymbol.Font = pFontDisp;
pTextSymbol.Color = pRGBcolor;
pTextSymbol.Size = Size;
pTextSymbol.HorizontalAlignment = esriTextHorizontalAlignment.esriTHACenter;
pTextSymbol.VerticalAlignment = esriTextVerticalAlignment.esriTVACenter;
pTextSymbol.Angle = Angle;
pTextSymbol.Text = Text;
//'set the size of the text symbol here, rather than on the font
//'Next, Give the TextSymbol and text string to the TextElement
pTextElement.Symbol = pTextSymbol;
pTextElement.Text = pTextSymbol.Text;
pTextElement.ScaleText = true;
ESRI.ArcGIS.Carto.IElementProperties3 aoElementPro = pTextElement as ESRI.ArcGIS.Carto.IElementProperties3;
aoElementPro.ReferenceScale = cGISHelpers.MapDomain.Map.MapScale;

Answer 1

We can very well add text which changes it size according to the scale. for this, we need to use the IElementProperties3.ReferenceScale Property.
I do not have C# code, but am attaching some sample VBA code that you can modify.
'--------------------------------
Sub ChangeTextElemRefScale()
Dim pDoc As IMxDocument
Dim pContainer As IGraphicsContainer
Dim pElement As IElement
Dim pTextElement As ITextElement
Dim pActiveView As IActiveView
Set pDoc = ThisDocument
Set pActiveView = pDoc.ActiveView
Set pContainer = pActiveView
'Loop through the graphics container
pContainer.Reset
Set pElement = pContainer.Next
While not pElement Is Nothing
'Get the specific text element
If TypeOf pElement Is ITextElement Then
Set pTextElement = pElement
If pTextElement.Text = "oregon" Then 'change this to your text element's text
Dim pElemProp As IElementProperties3
Set pElemProp = pTextElement
pElemProp.ReferenceScale = 15000000
End If
End If
Set pElement = pContainer.Next
Wend
pDoc.ActiveView.PartialRefresh esriViewGraphics, Nothing, Nothing
End Sub
'--------------------------------

Answer 2

To my knowledge, you can't get a TextSymbol to scale along with the map. That's because the TextElement isn't changeable based upon the map's extent but, instead, uses the font size to determine how large it's going to appear on the screen.
The best way that I can think of to do it while still using a TextSymbol is to change the point size (and, if the extent is large enough, hide/show the element) as the extent changes. I don't know of a "text control that pays attention to the extent," which is what you would really need.
Alternately, couldn't you just use an annotation layer or label the layer where you want the text size to change?

Answer 3

The ITextElement has got a property ITextElement.ScaleText. Set this to true and the text size will adapt automatically.