1. First, we open PS to create a canvas and create a new layer.
2. After opening, select the elliptical marquee option.
3. Create a circular selection on the oval selection.
4. Enter the stroke data of 1px for ellipse selection.
5. Then create a new layer again and name it: Rectangular Selection.
6. Select the rectangular marquee tool in the pop-up page.
7. Press shift+alt first, and then switch to the cross selection to create rectangular and oval cross selection.
8. Finally, press ctrl+del to fill the background color, thus solving the problem of filling the color with PS in the ellipse.