topic vb.net arcobjects create transparent buffer in ArcObjects SDK Questions

vb.net arcobjects create transparent buffer

LiYao — Mon, 08 Sep 2014 02:14:20 GMT

Hi all,

I want to check when a create a buffer on arcmap, how can I make the buffer transparent? I am using vb.net arcobjects.

Any advice will be appreciated.

Re: vb.net arcobjects create transparent buffer

DuncanHornby — Tue, 09 Sep 2014 09:36:09 GMT

Li,

Assuming your buffer exists in a layer and is not just some polygon then you can use the interface ILayerEffects to alter the transparency. Only layers support transparency, so if you were intending to create a polygon buffer and display it as a graphic then that will not work.

Duncan

Re: vb.net arcobjects create transparent buffer

LiYao — Wed, 10 Sep 2014 07:49:13 GMT

Hi Duncan,

Thanks for the reply. I have already create a transparent buffer (for polygon), but now I am unable to remove the colour of the boundary of the buffer.

Re: vb.net arcobjects create transparent buffer

RiverTaig1 — Thu, 11 Sep 2014 17:37:41 GMT

Actually you can get something that is pretty close to transparency on the ISymbol interface. So let's say you have created a graphic element (a IFillShapeElement could be a polygon or a rectangle as shown below). You will then find the the ISymbol:ROP2 and by setting it equal to esriROPMaskPen, it makes for a nice semi-transparent fill.

Dim fillShapeEl As IFillShapeElement

Set fillShapeEl = rect

Dim sfs As ISimpleFillSymbol

Set sfs = New SimpleFillSymbol

Dim rgb As IRgbColor

Set rgb = New RgbColor

rgb.Red = 255

'rgb.Transparency = 50 'This doesn't behave as expected...still 100% opaque

Dim sym As ISymbol

Set sym = sfs

sym.ROP2 = esriROPMaskPen 'This is the magic line!!

sfs.Color = rgb

fillShapeEl.Symbol = sfs

gc.AddElement rect, 0

Re: vb.net arcobjects create transparent buffer

LiYao — Fri, 12 Sep 2014 07:52:45 GMT

Hi Duncan & Taig,

I have already resolved the issue, thanks a lot for the attention and help.