Bug 7438

Summary:	Lower-case "m" in DejaVu Sans Mono 9 has rendering problems
Product:	freetype	Reporter:	Mary Ellen Foster <mefoster>
Component:	general	Assignee:	Werner Lemberg <wl>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	high	CC:	freedesktop
Version:	unspecified
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Attachments:	vim screenshot, immediately after typing vim screenshot, after forcing repaint vim screenshot, typing again after repaint

Description Mary Ellen Foster 2006-07-06 02:21:33 UTC

The lower-case "m" in DejaVu Sans Mono 9 loses its right-most vertical line. For
example, I'll attach screenshots from Vim 7.0 running under KDE on Fedora Core 5
with anti-aliasing turned on. The first one is right after I've typed the
characters shown; the second is after covering the window and forcing it to
repaint; while the third shows that, when I type some more into the window, the
newly-typed characters still miss the vertical bar, while the old ones look
fine. I have similar symptoms with "konsole" running on the same machine.

Comment 1 Mary Ellen Foster 2006-07-06 02:22:27 UTC

Created attachment 6134 [details]
vim screenshot, immediately after typing

Comment 2 Mary Ellen Foster 2006-07-06 02:22:54 UTC

Created attachment 6135 [details]
vim screenshot, after forcing repaint

Comment 3 Mary Ellen Foster 2006-07-06 02:23:16 UTC

Created attachment 6136 [details]
vim screenshot, typing again after repaint

Comment 4 Ben Laenen 2006-07-06 05:47:55 UTC

The problem occurs because the "m" glyph is too wide at that size.

Do you use the autohinter? If the answer is yes, then there is nothing we can 
do, the fix should be made in the autohinter, or in Qt, which should allow 
glyphs to be wider than the glyph width in monospaced fonts (Qt4 seems to be 
doing it right, but off course, we're still a long way from KDE4).

I can only see this effect at smaller sizes (8 and 9 ppem, which is probably 
around font size 6 on your screen). It should be fixed at those smaller sizes, 
but the problem you have occurs at larger sizes, and should not happen when 
the hinting instructions embedded in the font are used (i.e. when you enable 
the bytecode interpreter from FreeType)

Comment 5 Mary Ellen Foster 2006-07-06 06:29:11 UTC

Thanks for pointing me in the right direction: I checked my KDE settings and
found that I had set "Hinting style" to "medium" under anti-aliasing
configuration (I assume that's the default, as I'd never changed it). I get the
same symptoms with "slight"; with "none", the character is properly formed but
very blurry, while with "full" it looks all right.

Comment 6 Ben Laenen 2006-07-06 07:50:13 UTC

So the problem is fixed then? Odd, cause I never thought setting hinting style 
to full instead of medium would work.

I was talking about the autohinter in Freetype, where the bytecode interpreter 
should be used instead (because it gives a much better result). To my 
knowledge, Fedora doesn't include that bytecode interpreter due to patents. To 
activate the bytecode interpreter you have to compile Freetype yourself (or 
find a good rpm for it).

Anyway, as it is fixed, I guess I can resolve this into NOTOURBUG then

Comment 7 Nicolas Mailhot 2008-12-06 11:25:20 UTC

Mass move of freetype bugs to the new freetype product

Comment 8 Nicolas Mailhot 2008-12-06 11:27:47 UTC

Reopen the NOTOURBUG reports now they're correctly affected

Comment 9 Werner Lemberg 2008-12-06 16:16:45 UTC

I close this bug; it should be fixed since FreeType 2.3.3.

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