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Topic: Microsoft

Why ClearType doesn't work in Portrait mode

Summary: [Update 8/17/2007 - Vista puts Mac OS X font rendering to shame] I made an interesting observation over the weekend that almost had me thinking I was seeing things.  As it turns out I wasn't seeing things and font rendering technology like Windows ClearType won't work in "Portrait" (Vertical) display mode on LCD panels.

George Ou

By George Ou for Real World IT |

[Update 8/17/2007 - Vista puts Mac OS X font rendering to shame] 

I made an interesting observation over the weekend that almost had me thinking I was seeing things.  As it turns out I wasn't seeing things and font rendering technology like Windows ClearType won't work in "Portrait" (Vertical) display mode on LCD panels.  That means if you have an LCD that supports Landscape to Portrait rotation; the text is utterly unreadable if something like ClearType is enabled.  This also means that people who have "Slate" Tablet PCs that are held vertically simply will also have a hard time rendering text because ClearType becomes CrapType in vertical display mode.

Here's a side by side comparison of my display shot through my Digital SLR at maximum zoom at the closest range.  I was able to pick up the pixels so I can illustrate this effect.  The image on top is ClearType operating in the vertical orientation (Portrait) and the image on the bottom is ClearType operating in normal horizontal mode (Landscape).

As you can see, the rendering on top is atrocious especially if you look at the letter "m" while the bottom image looks fairly clean.  This phenomenon is described in this blog by Brandon Furtwangler where he uses a synthetic image to illustrate the effects.  Basically, LCD displays are lined up in columns of RGB (Red Green Blue) pixels and ClearType leverages that to produce clearer text.  But in Portrait mode the mechanism results in ugly text because the columns of RGB turn in to rows of RGB.

ClearType was actually something I praised in Vista (and still do for normal Landscape mode) but the Portrait mode absolutely stinks.  Microsoft either needs to come up with a ClearType that works in Portrait mode or at least automatically disable ClearType when the display is in Portrait mode but re-enabled for Landscape mode.  Please fix this Microsoft!

Topics: Microsoft, Hardware, Operating Systems, Software, PCs, Windows

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43 comments
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  • Didn't notice a differnce...Until

    I didn't notice a difference. So here I was trying to figure out what you problem was. Then I rolled back in my chair and stretch. That's when the difference really appeared. Stand back a bit and the portrait shot looks terrible. Up close where I normally sit I can't hardly tell the difference.
    voska
    Reply Vote

    • Look at the letter m and a again

      Look at the letter m and a again. It's not my imagination I can assure you of that.
      georgeou
      Reply Vote

      • I'm looking

        But I cannot find Waldo anywhere.

        The difference is purely cosmetic. I can still read the text from across the room.
        Bozzer
        Reply Vote

  • I don't get it!

    Both appear quite readable. Although you can notice more of the smoothing artifacts in the top picture it is hardly what I would call unreadable.
    ShadeTree
    Reply Vote

    • Look at the letter m again. It should be quite obvious.

      Look at the letter m again, especially the vertical lines. It should be quite obvious. This is actually a well known issue with a technical cause for it.
      georgeou
      Reply Vote

      • We are looking.

        But there really isn't THAT much difference. Have you ever considered it might just be you and not everyone else?
        Bozzer
        Reply Vote

        • No it's real

          It is not my imagination.
          georgeou
          Reply Vote

  • Pure Sensationalism

    "As you can see, the rendering on top is atrocious"

    Granted it isn't as good as the lower screen shot, it is hardly atrocious. I can read it quite well. Perhaps you need to visit the opticians or preferably limit the amount of exaggeration in your posts.
    Bozzer
    Reply Vote

    • Thats cause the image is a blow up

      If you shrank it back down to a normal size the top image would be very blurry whereas the bottom image would have good definition.

      There may be some exaggeration to George's post but I certainly wouldn't want to spend a long time looking at text rendered in the same way as the top image and I would agree that it should be sorted out.
      nmh
      Reply Vote

      • Try it yourself - No difference

        I have just shrank the image provided in Photoshop several times and there really is little difference. Try it for yourself.

        I imagine he used black on grey. Perhaps black on white just wasn't working for him.
        Bozzer
        Reply Vote

        • This is a photograph of the actual screen.

          It is not uncommon in this case for a white background to appear gray.
          ShadeTree
          Reply Vote

          • You're exactly right, it was a white background

            You're exactly right, it was a white background. It looks completely white but blown up you can see the gaps between the pixels making it look grey.
            georgeou
            Reply Vote

          • Yeah I have taken a few pixel shots myself(nt)

            .
            ShadeTree
            Reply Vote

        • That's a pointless suggestion

          You need to try this by rotating an actual monitor, not shrinking pictures of the monitor. Shrinking pictures in no way represents how the hardware renders the text. And neither does displaying a picture of a monitor screen on a different monitor screen.
          aep528
          Reply Vote

    • I have better than 20 20 vision, good color, and depth perception.

      I have better than 20 20 vision, good color, and depth perception. My eyes are quite good.
      georgeou
      Reply Vote

  • Almost no difference, but ...

    I'm looking at the images on a 17" LCD monitor with WinXP not at actual ClearType text on a Vista machine but they look almost identical. Maybe the effect is much more obvious under actual conditions but from looking at the images there's virtually no difference.

    Does Vista/ClearType have anti-aliasing or similar technology and changing those settings might make a difference? Is it perhaps the specific monitor or monitor model? Does it matter which font is being used?
    Rick_R
    Reply Vote

    • Why is the background such a dark color?

      I'm sure if you had a nicely contrasting background color, it'd show up much better...
      KWierso
      Reply Vote

      • This was a pure white background

        It was a white background. It looks completely white but blown up from a photograph you can see the gaps between the pixels making it look grey. Try taking a zoomed in photo yourself of your own LCD and you'll see this same thing.
        georgeou
        Reply Vote

  • Sub-pixel rendering

    The issue here is subpixel rendering gets whacked because the RGB order changes.

    The solution for Cleartype is simple: download the tuning wizard and re-adjust your cleartype settings when in landscape or portrait mode.

    BTW, nice intimation that all sub-pixel rendering algorithms suffer from this problem. That may or may not be the case. It depends on whether the subpixel rendering is smarter on Linux or OS X and recognizes the monitor twist.
    frgough
    Reply Vote

    • Since Microsoft is incapable of innovation....

      .... they must have stolen this from either Linux or OSX and therefore one or the other or both will exhibit this same issue. Aren't you being just a little over sensitive?
      ShadeTree
      Reply Vote
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