Why is this happening? Photoshop Related (Pic)

im trying to draw a perfect circle by holding down the shift key and using the elliptical marquee tool. then filling in the line via stroke. and this is what happened

ive tried both clicking and unclicking anti alias. ive tried setting the 'stroke location' inside center and outside



why are the edges squared off like that?

designs216 said:

Perhaps you drew the circle and then expanded the canvas size? When the selection got close to the original document bounds, it would snap to the document edges which are, of course, flat.

Click to expand...

i see what ur saying but thats not at all what happened...i drew the circle within the confines of the canvas size so this shouldnt be happening
and also .the reason it looks pixelated is because i enlarged it so u all could see where it squares off..