CODEWITHSUNDEEP
fontsrenderrgb
Eric
Eric

Reputation: 2034

Why does text render with red, green, or blue in separate pixels on the edges of the letters, rather than light grey?

I'm not asking about RGB, what I'm talking about is the edge of letters when zoomed in on a browser. I've never seen another application do this.

Upvotes: 3

Views: 1459

Answers (2)

Rychu
Rychu

Reputation: 1020

According to my understanding this technique works on monitors that has single color point arranged in columns (so, column of R, column of G, column of B).

If you think of edge between white and black area, you will get something like this (where dos is an unlit point):

RGBRGB......

Now, darkening the rightmost subpixel will move the perceived edge by 1/3 of the pixel. And this this the main benefit of removing a single component instead of partially darkening all three - it gives sharper edge, while putting a gray pixel would give an impression of edge being more blurry.

So, moving steps would work like this:

RGBRG.......
RGBR........
RGB.........

This works, because no matter what is the leftmost lit color point, there always are all three consecutive components, just in different orders (RGB, GBR, BRG), which is perceived as a sigle white point.

Upvotes: 1

David van Driessche
David van Driessche

Reputation: 7046

This is typically an anti-aliasing technique which intends to make the text look less jagged and more legible. On some operating systems, the OS will allow you to setup how much of this effect is used because it's effectiveness can depend on the technology used for the monitor and personal preference.

Microsoft refers to this technique as ClearType: http://support.microsoft.com/kb/306527

Upvotes: 5

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