Update: CWS provided a solution in comment: opening Terminal and entering
defaults -currentHost write -globalDomain AppleFontSmoothing -int 2, after re-login, everything is back to normal again!
Update: Turns out the problem is not just from Dell, various 3rd party display manufactures including Samsung, LG, HP and EIZO also have the same issue.
A very tricky issue has been bothering me for a few months: in Snow Leopard, whenever I connected my Dell 2408WFP monitor, every app launched after that will have sub-pixel antialiasing (aka. LCD Font Smoothing) disabled.
For a typography freak like me, it is a huge disaster.
The full story comes in two parts:
Prior versions of Mac OS X used to have this “Font smoothing style” option in System Preferences -> Appearances, it is not as complete as fontconfig. But good enough for general public. A very unfortunate thing I covered about a few months ago is, they simplified that option to a checkbox: Use LCD font smoothing when available.
But how did Snow Leopard determine whether it is “available”? It relies from information retrieved from the driver of the display. Let’s say if you have ten displays connected, and one of them is a CRT display instead of LCD, then all the applications in your system will not be able to use LCD font smoothing. Here comes the epic fail: Dell 2408WFP (and Dell 3008WFP, AFAIK), a perfectly fine LCD display, is not recognized as one by Mac OS X (both Leopard and Snow Leopard have this issue, I haven’t check earlier versions).
(Though my Dell 2408WFP is not recorgnized as a LCD display in Leopard, I can force sub-pixel rendering with the “Font smoothing style” option.)
With the combination of these two problems, I’m stucked. Either I can give up Snow Leopard or get a new display. But I simply don’t have enough space on my desk for another display. (And I really happy with the Dell 2408WFP, it works with all other devices: Xbox 360, Wii, PS2, etc., so I won’t abandon it for an Apple LED Cinema Display for apparent reasons.)
This morning I just got a reply for my bug report from Apple Developer Connection, it said:
Thank you for contacting us regarding Bug ID# 6975903. The report you have submitted has been determined by engineering to be an issue with LDC Display. Please know that we are doing our best to inform Dell of the issue with the hope that they can implement the necessary changes. Please feel free to contact them regarding this issue to help alert them of its importance.
I felt even more desperate after receiving this. Because it seemed too rare that Apple (and Dell) won’t even care to fix. And since I have little knowledge about why and what need to be fixed from Dell, it will be really hard for me to push Dell on this issue.
To be honest, what I’m asking is pretty simple: if we cannot get back the original font smoothing level option, at least give us a hidden preference item to turn on LCD font smoothing, that won’t hurt the usability of Snow Leopard, right?