Which is the correct sub-pixel font rendering setting?

Asked by linuxsapien on 2011-11-23

There are four main font rendering engines within Ubuntu.

One will find these in the "appearance Preferences", then the "Font" tab.

If set to "Sub-Pixel Smoothing", and if one clicks the "details" button, there we will find the "Sub-pixel Order".

The question really, is, how does one know which way the LCD monitor is displaying these?.. By selecting each there is a very subtle change, but from what I gather, its the RGB and BGR that achieve what i would consider "best". Though I do understand that the vertical display has a slight top and bottom "blur". What is this trying to do to the font?

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Paul Sladen (sladen) said : #1

Most modern TFTs are arranged with sub-pixels in the order 'Red-Green-Blue;Red-Green-Blue' (RGB) running horizontally left-to-right. This will be correct in about 90% of cases.

The other settings are there to deal with 'tablet'-type use cases. Putting a widescreen monitor arranged as portrait will mean that the pixels now go RGB *vertically*. If upside down they'd be BGR horizontally, and 90-degrees rotated again they would be BGR vertically.

Using a magnifying glass (or borrowing somebody's eyewear) should allow the chance to look at a section of white screen area close-up. The ordering should be visibly apparent.

On a CRT monitor with a triangular arrangement of sub-pixels, the settings are not useful. It is best to disable sub-pixel anti-aliasing when taking screenshots for publication, as unless your setup matches the viewer's setup, the effect will be counter-effective.

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