Circle or ellipse stroke and fill slightly different pixels

[ljbade]

If you try to draw a filled circle or ellipse over a stroked version with the same dimensions like:

    graphics.draw_circle(
        Circle::new((BUFFER_WIDTH / 2, BUFFER_HEIGHT / 2), 100),
        stroke(RED),
    );
    graphics.draw_circle(
        Circle::new((BUFFER_WIDTH / 2, BUFFER_HEIGHT / 2), 100),
        fill(GREEN),
    );

Then I would expect to see no red pixels if the fill covers the same pixels that the stroke outlines.

However instead I see some red pixels:

I think the problem is that you need to add a half pixel offset when calculating if a a pixel's midpoint is inside the circle.

[emmabritton]

I tried your suggestion but it didn't seem to make any difference to me, I'm fine with the current implementation but if you have any other ideas or if you want to make a pull request I'll happily look at them.