[mythtv] underscan OSD only

[Bruce Markey]

Jim Paris wrote:
> My TV overscans about 5-7% on each border.  I am connecting to it
> through VGA and if I display video full-screen, the sizing is perfect.
> For the GUI, I've set the dimensions to match what the visible area.
> No problems there.  For TV playback, I have two options:
> 
> - Set GuiSizeForTV with overscan percentages = 6.  Then,
>   the OSD fits within the viewable area, but the video size
>   is slightly off due to rounding errors etc, and it's being
>   scaled unnecessarily.
> - Disable GuiSizeForTV; then the video is fullscreen and displays
>   perfectly but the OSD also extends into the overscanned area.
> 
> I want to add a third option which will still display the video
> fullscreen but shrink the OSD by 6%, say, "Over/Underscan OSD Only".
> All the dispx/dispw/imgx/imgw/XJ_width/winw/etc stuff is confusing;
> rather than staring at the code for too long, could someone point me
> to the appropriate place to set this sizing?  (Or smack me if I'm
> missing something obvious?)

SMACK! ;-)

Use method 2, disable GuiSizeForTV then use the GUI* sizes
on the same page to size and position the GUI.

+--------------+------+----------+
| value        | data | hostname |
+--------------+------+----------+
| GuiWidth     | 600  | nordtv   |
| GuiHeight    | 472  | nordtv   |
| GuiOffsetX   | 17   | nordtv   |
| GuiOffsetY   | 7    | nordtv   |
| GuiSizeForTV | 0    | nordtv   |
+--------------+------+----------+

My X display area is 640x480 and the is the size of my slightly
overscanned fullscreen TV display area. My GUI is 40 pixels
narrower and 8 pixels shorter. The settings page lets you change
these by 8's and the GuiOffset* (upper left corner position)
by 1's. This allows placing every edge very accurately. Assuming
perfectly straight edges (ya, right =). you could get every edge
within 4 pixels.

The problem with using a simple percentage to shrink the GUI is
that you would probably only get one edge close with the other
three off (unless your TV image is amazingly well centered).

--  bjm