JSAPI is not honoring transparency setting in map service

Question

I have a map service with a dynamic layer that has a transparency set to 50 on it.
When its brought into ArcMap the transparency is honored but when brought
in using JSAPI it doesn't honor it. I'm using version 3.3.

Is there a fix for this?

ShawnCarson · Answer

Thanks Marcus & Gibby. Your solutions worked for me.

FYI: If you use a esri.layers.FeatureLayer it seems to respect the opacity no need to set an image parameter....

Anonymous User · Answer

Actually....this works well too:

var imgParams = new esri.layers.ImageParameters;
imgParams.format = "PNG24";

var yourMap = new esri.layers.ArcGISDynamicMapServiceLayer("http://yourURL/ArcGIS/rest/services/yourMapService/MapServer", {"opacity":0.6, "imageparameters": imgParams});

YvanBérard · Answer

I had this problem and i sent a ticket to ESRI.

I had two layers, one a tiledservice (MrSID imagery) and a dynamicservice of polygons.

The inside of the polygons were empty but when adding the polygon over the tiled service, the transparency and the antialiasing weren't working at all. But when we set the image format to png 32 of the dynamicservice with your trick, it all work fine.

But, if you check the documentation in the API, it says that you need to use the function setImageFormat or the pass the parameter imageFormat in the creation of you TiledService, but it won't work. But with your trick, it works very well.