[1 mod] Hinting: Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM

Bug #864118 reported by Thaddee Tyl on 2011-10-01
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Ubuntu Font Family
Medium
Unassigned

Bug Description

I am using konsole, with sub-pixel anti-aliasing enabled and manual hinting. At 11 PPEM (6x12 pixels) the lowercase bold 'm' is only drawn with single-width stems, where all the other bold characters have jumped up to double pixel stems. The bold 'm' is also only being drawn at 79% intensity of the other single-stem characters.

Proposed solution:
  1. There is no suitable obvious solution (not enough pixels) in B&W
  2. For grayscale, try to use 1.3 pixels per leg, and use full 7-pixel width for outer stems

Paul Sladen (sladen) wrote :

Thaddee: Thank you for spotting this too. Please can you post a also screenshot showing exactly what you're seeing with the lowercase 'm', in context that you're seeing it.

For this one, please could you also copy and paste the two special debugging characters U+EFFD and U+F000 ('' and '') into the terminal or editor before taking the screenshot.

Once again, thank you for taking the time to report this!

tags: added: uff-monospace
Changed in ubuntu-font-family:
status: New → Incomplete
Thaddee Tyl (thaddee-tyl) wrote :

The word "pencil.html" at the end of the first line is in bold. The word "meta" on the second line is, too.
The debug characters are in the "lang" attribute on the second line. Note that, following the second character, there is a double-quote that is partially shadowed.

Thaddee: excellent, the screenshot shows what you're seeing clearly, and the read out appears to be hinting enabled;11 PPEM (pixels per em, the height).

I'll warn you though that it may be very hard to try and solve this. At 11 PPEM there are only 5 pixels available horizontally (2:1 ratio of height:width). That's not enough fundamental space to give both of the outer stems 2 pixels, and leave 2 pixels of space, and still fit in the middle stem.

summary: - Mono: bold lowercase letter "m" is not bold.
+ Mono: bold lowercase letter "m" is not bold @ 11PPEM
summary: - Mono: bold lowercase letter "m" is not bold @ 11PPEM
+ Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM
summary: - Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM
+ Hinting: Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM
tags: added: uff-bold uff-hinting
Changed in ubuntu-font-family:
importance: Undecided → Medium
milestone: none → 0.81
status: Incomplete → Triaged
Paul Sladen (sladen) wrote :

Looking at the screenshot, the cells are actually (6x11 pixels), but that's still not enough pixels to get a good rendering of the 'm'. However it's also being drawn under-intensity, having only 79% of the brightness of other corresponding pixels which would imply that the grid-fitting isn't snapping the stem to even the full pixel stem-width.

Hopefully Vincent can try some tinkering.

description: updated
Paul Sladen (sladen) on 2011-11-24
summary: - Hinting: Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM
+ Mono: Hinting: bold lowercase letter "m" is not heavy enough @ 11PPEM
summary: - Mono: Hinting: bold lowercase letter "m" is not heavy enough @ 11PPEM
+ Hinting: Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM
Shiraaz Gabru (shiraaz) on 2011-11-27
Changed in ubuntu-font-family:
milestone: 0.81 → 0.9x-hinting
Paul Sladen (sladen) on 2011-11-27
description: updated
tags: added: uff-mono
removed: uff-monospace
summary: - Hinting: Mono: bold lowercase letter "m" is not heavy enough @ 11PPEM
+ [1 mod] Hinting: Mono: bold lowercase letter "m" is not heavy enough @
+ 11PPEM
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