Hi everyone. This is an issue I have been trying to tackle for a while and decided to reach out for help. I am creating an ESRI ArcGIS Desktop Add-In that allows the user to draw a polygon and then have it added to the map. I am able to capture the polygon and add it to the map, the issue is the transparency. Currently and by default it is 100% opacity and solid. I want to make it around 50% opacity so the user can see the data behind it.
Here is the code I have so far:
public static void AddPolygonToMap(IActiveView ActiveViewInstance, IGeometry NewGeo)
{
//Local Variable Declaration
var fillShapeElement = default(IFillShapeElement);
var element = default(IElement);
var graphicsContainer = default(IGraphicsContainer);
var simpleFilleSymbol = default(ISimpleFillSymbol);
var newRgbColor = default(IRgbColor);
var lineSymbol = default(ILineSymbol);
//Use the IElement interface to set the Envelope Element's geo
element = new PolygonElement();
element.Geometry = NewGeo;
//QI for the IFillShapeElement interface so that the symbol property can be set
fillShapeElement = element as IFillShapeElement;
//Create a new fill symbol
simpleFilleSymbol = new SimpleFillSymbol();
//Create a new color marker symbol of the color black;
newRgbColor = new RgbColor();
newRgbColor.Red = 0;
newRgbColor.Green = 0;
newRgbColor.Blue = 0;
//Create a new line symbol so that we can set the width outline
lineSymbol = new SimpleLineSymbol();
lineSymbol.Color = newRgbColor;
lineSymbol.Width = 2;
//Setup the Simple Fill Symbol
simpleFilleSymbol.Color = newRgbColor;
simpleFilleSymbol.Style = esriSimpleFillStyle.esriSFSHollow;
simpleFilleSymbol.Outline = lineSymbol;
fillShapeElement.Symbol = simpleFilleSymbol;
//QI for the graphics container from the active view allows access to basic graphics layer
graphicsContainer = ActiveViewInstance as IGraphicsContainer;
//Add the new element at Z order 0
graphicsContainer.AddElement((IElement)fillShapeElement, 0);
//Show the new graphic
ActiveViewInstance.Refresh();
}
I know that this is possible somehow and I am sure it's just a line or two missing but any help would be much appreciated.
V/r,
Josh