Antialias / Hinting issue

[wez]

I'm playing with this crate. In this particular scenario I'm rendering a horizontal line into a pixmap that is 8 pixels wide and 16 pixels high. I set the stroke width to 1 pixel, and the line y coordinate is 8.

The resultant bitmap data is:

> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 7f7f7f7f 7f7f7f7f 7f7f7f7f 7f7f7f7f 7f7f7f7f 7f7f7f7f 7f7f7f7f 7f7f7f7f
> 80808080 80808080 80808080 80808080 80808080 80808080 80808080 80808080
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

which looks like the line might be rendering at y = 7.something. This renders as a fainter grey color on screen, which is undesirable.

If I turn off anti-aliasing then the line renders at y = 8 at full intensity.

Is the anti-aliasing behavior a bug, or do I need to do something to manually hint the y position (perhaps offsetting by half the stroke width)?

[RazrFalcon]

This is the expected behaviour. Skia produces exactly the same output.

I don't think it can be "fixed".