Mono: Shaded glyph resolution and tilabilty in Ubuntu Mono (U+2591, U+2592, U+2593)

[Artis Rozentāls]

The shaded glyphs in Ubuntu Mono, while way ahead of just about any other outline font simply by not leaving gaps in gnome-terminal, still suffers some of the common problems.

First of the level of detail is much higher than the rest of the glyphs, leading to artefacts at small sizes as well as color shifts (apparently when subpixel rendering tries to cram in all the detail). It also makes them look unbalanced next to letters with larger sizes.

The other one is tiling. Aside from the top-bottom of U+2593 all the glyphs start and end in the same configuration, this creates obvious seems when they are placed next to each other.

The attached image illustrates each of these.

[Paul Sladen (sladen)]

Yup. Virtually all other monospace fonts are based around a "knights move" pattern on an 8x16 grid (for 25%, 75%), and a 1x1 diagonal or 1x2 double diagonal grid (for 50%).

[Paul Sladen (sladen)]

Uploaded 24 February 2011 to bug #724022, the original SVG/PDF file with designs for the shaded glyphs build using knights moves on an 8x16 tile-able grid:

   https://bugs.launchpad.net/ubuntu-font-family/+bug/724022/+attachment/1868141/+files/ubuntu-mono-required.set-1.pdf
   https://launchpadlibrarian.net/65045631/ubuntu-mono-required.set-1.svg

[Paul Sladen (sladen)]

These want re-drawing using an 8x16 or 8x8 grid, eg. as shown in the original drafts on comment #3. Odd-numbers of rows/columns, while quite beautiful on their own, don't tile when using consecutively in large block areas.

[Shiraaz Gabru (shiraaz)]

We've updated the three shaded glyphs, even number of rows and columns, 8x16 grid, see PDF attached before and after.

We also considered the wallpaper/tile comments, see pattern on PDF attached.

Regards
Shiraaz
Dalton Maag

[Paul Sladen (sladen)]

Artis: are the redesigns posted by Shiraaz in comment #5 acceptable? These gives coverages of:

  25% BLOCK => 13% ink coverage
  50% BLOCK => 25% ink coverage
  75% BLOCK => 75% ink coverage

The other change here is the pattern; the 75% is using a rectilinear layout rather than just being the inverse of the 50% BLOCK. This that okay, or does it introduce too much of a visible pattern?

[Artis Rozentāls (artis)]

That looks like it should work. The design itself seems tile-safe, the rest would depend on proper spacing.