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ClearType question for Bill H :)

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    Harlequin

    I was zooming in on a submit button using ClearType(I was turning it into a grahic), and I noticed the text is generated with red on the left-side of the letters and blue on the right-hand side of the letters. What's the reasoning behind this?

    It also struck me that, if I remember right, 3D glasses were red on the left and blue on the right...

  • User profile image
    Sven Groot

    This is called sub-pixel anti-aliasing. Because of the position of the individual colour elements in a pixel in relation to the adjacent pixels, our eyes do not perceive the colour but rather think that the coloured pixel is part of one of the neighbouring pixels, thus achieving smoother text. Only when you zoom the text does this become apparent.

    This is also why ClearType works better on LCDs: the position of each colour element is fixed on an LCD screen.

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    Cannot​Resolve​Symbol

    As to why it's one color on left and another on right, it's because the leftmost subpixel is blue and the rightmost subpixel is red.  Here's a good article about subpixel antialiasing:  http://today.java.net/pub/a/today/2005/07/26/lcdtext.html

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    W3bbo

    Sven Groot wrote:
    This is also why ClearType works better on LCDs: the position of each colour element is fixed on an LCD screen.


    Here's something I've never understood:

    If on a TFT display each pixel is an absolute color, compared to CRT where each "pixel" is actually 3 sub-pixels, then how does sub-pixel rendering work since that would introduce a visible red and blue line along each side of a glyph?

    Here's another problem with ClearType's implementation of subpixel rendering: When you have two lower case "L" characters next to each other: iililililililiillll you can sometimes see the red at a distance.

  • User profile image
    scobleizer

    Have you watched all the Bill H interviews and with the ClearType team? They explain why this color fringing is there when you enlarge a character glyph.

  • User profile image
    Harlequin

    Yeah, have seen all the videos. I was just wondering why the reds were on the left and the blues are on the right. The link up above explains that half way down the page Smiley

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    Andrew Davey

    When I rotate my tablet PC into portrait clear-type is useless and actually degrades the quality of text. Also when rotated to 180 degrees clear-type is effectively backwards!
    Is there any software to switch clear-type on/off depending on screen orientation? Or even better change the mode of clear type between Off, RGB and BGR.

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