Why is the resulting circle defective?

[xietao]

Here's my code: gdispGFillCircle(g, 120, 120, 30, HTML2COLOR(0xFF8D1A));

And Anti-aliasing is turned on.    #define GDISP_NEED_ANTIALIAS                     GFXON

 

[Joel Bodenmann]

Hi,

Can you please provide more details? What do you consider to be defective?

[xietao]

11 hours ago, Joel Bodenmann said:

Hi,

Can you please provide more details? What do you consider to be defective?

As you can see, the resulting circle has some missing corners, how should I fix it?

[inmarket]

Anti-aliasing is something that is currently only supported by font rendering. Circles (or any drawing operation other than fonts) are never anti-aliased. The reason for this is the amount of code and the complexity in the drawing operations make it not suitable for such a small graphics library as uGFX. Anti-aliasing operations are also very slow for most of the displays uGFX support because it requires reading back from the display frame-buffer, an operation that is very slow on many devices. Of-course, if your display is not capable of read-back (and many aren't), anti-aliasing will not work at all, even for fonts.

If you want to anti-alias your circle, a would suggest drawing a circle 1 pixel larger diameter in a color that is a blend between the circle color and the background color. Then draw you circle on top of that. That will have the effect of filling in the edge pixels.