Justin Hornsby wrote: > I was dreading this. We take it for granted that a TV picture fills the screen, The illusion is that the picture size is identical to the screen size but this is impossible. The raster size is larger than the screen and the rough edges are cutoff by the cowl. A TV tube has slightly curved edges and rounded corners. This is the traditional shape of a TV screen:
http://upload.wikimedia.org/wikipedia/en/7/75/Television.png Imagine ProjectGrayhem displayed on this TV, especially the icons in the upper right corner. Modern tubes and cowls do a better job of giving the illusion that the picture is rectangular but the issue still exists. Another factor is that the picture can't be perfectly centered so there needs to be enough overscan to cover the middle of all edges and there may be more overscan on one side than the other or top or bottom. > On the minus side, people who have displays which don't overscan will All several billion TVs that have ever been made since the '40s are supposed to overscan unless they are misadjusted or broken. TV production, broadcasters and devices designed for TV display have all agreed to follow the SMPTE standards for several decades so that picture elements and text will fit for all TVs. If you look at TV graphics, VCR OSDs, the TV's own OSD, DVD menus, video game consoles, commercial DVRs, they all follow this standard. A common trick is to have graphic elements that flow off the screen but if you look at the text, it all falls within the smae margins from the edge. > I thought that's why myth had the facility to scale the GUI. It's ironic that myth is a TV application that wasn't designed to be displayed on a TV =). We should have started by insisting that the SMPTE margins were used but this hasn't been the case. The setup wizard pages are particularly bad (but this doesn't mean that themes and OSD themes have to be just as bad too). Myth GUI size is actually a hack in response to the self imposed problem. The GUI size can be tweaked and centered to try to match the edges of the GUI to the edges of an individual screen so that GUI elements near the edge won't be cutoff. However, if the GUI has little or no margin space, it is difficult to impossible to match it perfectly and there is nothing that can be done for elements in the corners if the screen has rounded corners. None of this would be necessary if we adhered to the action safe and title safe areas. For OSDs, there is no GUI size adjustment (nor should there be) and we need to be more strict about the margins. These are much easier to fix than the GUI pages. The problem comes from the fact that if a theme designer doesn't think about a TV screen, they tend to think of the rectangular window on their desktop as the space they have to work with. They should actually see it as blacked out as least 2%-3% on all sides with curved corners. [A related problem is that fonts chosen from two feet in front of a monitor may not be readable on a 19" screen from ten feet away.] Any action, movement, or object that is supposed to be seen should be 5% in from the edge and any text that needs to be read should be 10% in. However, 10% is probably overkill these day. Tickers like CNN usually fall in the space between 5 and 10 percent. So, for an 800x600 GUI design, graphics that don't flow off the edge should fall inside 40-760 and 30-570. Something right at 40,30 or 760,570 may still be cutoff on some screens but that's the TV's problem. You've done your part... that's why there is a standard =). Text should be further in if possible but really, having a margin of at least 30 or 40 solves most of the problem. -- bjm _______________________________________________ mythtv-users mailing list [email protected] http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
