Pixelated edges when changign background color?

[aquastealth]

Hello I know there is a tool or setting in Photoshop
that makes your edges look cleaner and less pixelated
while switching from a dark to a light background color
but I just cant find it, could anyone please help me?
I added a picture to show you the problem:


Thx for listening/ AquaStealth

[tamlin]

Make sure that Anti-alias is turned on when you draw your shape.

[aquastealth]

Thx for the answer, thats it but at the same time not really
what Im looking for.
I remember someone showing me how to get rid of this kind
of pixelation/edge distortion even if you import a premade
(one layered) image into photoshop.
Imagine that you have a portrait of a person with black
background and want to change the background to white
with the paint bucket tool then there was a method
or a tool that could fix these kind of pixelation problems?
Anyone know what Im talking about?

[Tony_photoplus]

I have gone through the little I know and would use a blur tool, rubber or smuge. If I have the area selected I would use the smooth option. It is an area that I think is not an instant fix, only a time consuming process. If needed I would use a mask.

Sorry thats all I have. I have looked through all my plugins but none I see that would achieve the finish product that you require.

[Jacorre]

When you're saving your image, use the Matte option. For example, if you know you're image will be on a black background, then make your Matte color black. What it does is add some black around the edges of your image to blend in with the background color.

Not sure if that was what you're asking though!