On Wed, 14 Jan 2004, Douglas Alan wrote: >I have a Sony LCD monitor (an SDM-X73, in case that is relevant), and am >trying to use it on Red Hat 9.0 with the monitor's DVI input. It works >fine for a while, but then something inevitably happens where with black >text on a white or grey background, there are annoying color auras >around the letters. There are several different colors of aura and >different letters will have different colored auras. A wide letter, >such as an "m", may have different auras on its different parts. > >Some other data that might be relevent: > > - This problem does not happen if I use the monitors VGA input, > rather than the DVI input, but I would prefer to use the DVI input. > > - This same problem happens on two different computers that have the > same model of monitor, so it doesn't seem like the problem is a > flakey monitor. > > - Power cycling the monitor does not fix the problem, even for a > period of time. > > - Rebooting the computer will fix the problem, but only for a while. > > - Switching video cards from an ATI model to an nVidia model does not > fix the problem. > > - The problem is not very noticable with fonts that are very thin -- > they have to have a bit of thickness to them for the problem to be > readily apparent. > > - Alas, I don't have a different model or make of LCD monitor with a > DVI input to see if the problem occurs with all DVI displays, or > just this model. > > >Any ideas on what is going on here and how I might fix it? You're using subpixel antialiasing, and probably have the subpixel orientation incorrectly configured. Run the font properties dialog and try the various different options. If none of them are appealing, disable subpixel antialiasing. I believe the properties dialog calls it something more user friendly like "font smoothing" or somesuch. For those who have no idea what I'm talking about, subpixel rendering is a technique which is useable on LCD displays where the rendering of fonts and other graphics can be improved by knowing the order of the red, green and blue components on the LCD display. By knowing wether they go from left to right or top to bottom, and wether they are RGB or RBG in order, the horizontal or vertical resolution can be virtually tripled on the display, by addressing individual color components rather than treating each pixel on screen as a traditional pixel. This allows fonts, lines and other images to be rendered much more nicely as the resolution is effectively tripled in one direction. However, if the orientation or order is misconfigured, this will result in color information intended by the font rendering engine, being interpreted differently by the LCD display, and blue or reddish orange blur effects become visible at the edges of fonts. For detailed information on how and why this works, to understand how you can benefit, see: http://www.grc.com/cleartype.htm Hope this helps. -- Mike A. Harris ftp://people.redhat.com/mharris OS Systems Engineer - XFree86 maintainer - Red Hat -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
