I once implemented SDF text rendering. To me, the thing I liked the most about this technique it how easy it is to add effects on top. With a few lines of shader code, I had outlines and softening of the edges (antialiasing). I didn't try the MSDF variant, as I didn't mind corners not being sharp when scaled up, so I don't know if these effects break on MSDF.
Slug doesn't seem to support any of these, it is just "for a given point, am I in or am I out?", but it doesn't tell you by how much, which is great on really high resolution displays and large sizes, but you would lose the ability to do the kind of effects you can do with SDFs, and have to deal with antialiasing separately.
> Slug doesn't seem to support any of these, it is just "for a given point, am I in or am I out?", but it doesn't tell you by how much
It does give you an anti-aliased value between 0 and 1 that estimates how much of a pixel is being covered.
But this is a linear estimate based on horizontal and vertical distance to the Bezier curve. It does not look correct at long distances, which is why you shouldn't use it for outlines, drop shadows or the other cool things you can do with (M)SDF. A single pixel outline works fine but is not really legible with modern display resolutions (very thin lines).
For finding the minimum distance between a quadratic Bezier curve and a point would require solving a 3rd degree polynomial, where Slug's algorithm gets away with solving a quadratic equation per pixel. This is makes a big performance difference.
GuB-42 · · focus · HN ↗
Slug doesn't seem to support any of these, it is just "for a given point, am I in or am I out?", but it doesn't tell you by how much, which is great on really high resolution displays and large sizes, but you would lose the ability to do the kind of effects you can do with SDFs, and have to deal with antialiasing separately.
exDM69 · · focus · HN ↗
It does give you an anti-aliased value between 0 and 1 that estimates how much of a pixel is being covered.
But this is a linear estimate based on horizontal and vertical distance to the Bezier curve. It does not look correct at long distances, which is why you shouldn't use it for outlines, drop shadows or the other cool things you can do with (M)SDF. A single pixel outline works fine but is not really legible with modern display resolutions (very thin lines).
For finding the minimum distance between a quadratic Bezier curve and a point would require solving a 3rd degree polynomial, where Slug's algorithm gets away with solving a quadratic equation per pixel. This is makes a big performance difference.