Strange graphics bug (fine lines)

I get a strange graphics bug when typing: suddenly 1-3 fine, grey lines appear a couple of lines above where I am typing (cf. attachment). I can’t exactly reproduce it, but it seems to appear only when I am using the page view and when there is a page break close to where I am writing (cf. image). It does not happen in any other program (i.e. text edit, Pages etc.).

I am using a late 2009 MBP, Mac OS 10.8.2, Scriv 2.3.1 (20025) non-AS version, and I use a BENQ GL2450 as my main monitor (MBP in clamshell mode).

Hi,

Unfortunately these artefacts can appear on occasion. They are caused by the inexact scaling routines of the OS X text system (they only appear if you scale the view, as you have done to 150%). I’ve done a lot of work to ensure they don’t appear, but it seems that there are rare circumstances in which they can still crop up (frustratingly, given just how many hours and days I have put into this…). If you can get reproduce this consistently, please send us the project (or a sample project) with instructions on how we can get to see the lines as well (I haven’t reproduced them for months now), and I’ll take another look.

All the best,
Keith

Just wanted to chime in and say I’ve got them too.
I am working at 150% too, but I’m pretty sure I’ve seen them at 125% as well.
100% is unfortunately much too tiny on my screen…

Problem looks exactly the same as on the thread starters screenshot, with one exception: Opening both in Pixelmator and comparing their pixel values, his lines are (RGB) 190, 195, 203 while mine are 251, 251, 251 — which makes my lines slightly lighter.

Just a thought here: Might it be that these lines are remnants from some part of the page element using some color setting we might have set differently?

lines.jpg

EDITED TO ADD: I’m not sure my guess is quite right — it seems the color of the lines may actually vary. I did some writing and decided to make a screenshot of the lines as they appear (which on my computer is more often than not) and noticed that they come in different shades of gray. However, on my machine they always seem to be equal in R, G and B values, not different as in the original poster’s screenshot.

FWIW, I didn’t have them on my previous computer, an MBA 2011 10.6" running mountain lion. For me, they started when I switched to an MBA 2012 13" and since then they appear all the time. Perhaps a graphics card issue?

It’s “tearing” caused by scaling in the text system. It does seem to vary between machines, but it does only happen in scaled text. Essentially, scaling can cause the drawing not to occur on precise pixel boundaries. As this drawing is handled by the text system, I can only try to mitigate it where possible. Is this Retina or not, and are toy in page view, and is it centred? I doubt there’s much else I can do beyond what I’ve done already, but, as I say, I’ll look if you can provide a reproduction case. (Remember, too, that you can always use a larger font and reduce the size at compile time.)