Lower Resolution (20x8?) Text on TV??

Stan671

I've been studying and fiddling around with the TV_Text object.· I like that it uses the built-in fonts and very little RAM for program and data.· I like that the color can be specified for each character.· I have even got it going using 16 different colors.

However, the text is way too small and hard to read on my tiny 2.5" TV Parallax TV screen.

Could this concept to extended to put less characters on the screen so that they can be larger and easier to read on small screens?· Something·in the neighborhood of·20 columns by 8 rows would be fine for my purposes.

I know that the TV Graphics object can do text of different sizes, but there is WAY too much overhead involved with this just to display simple text.

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Stan Dobrowski

Mike Green

Take a look at Bean's (Hitt Consulting) Propeller Video Overlay gadget.

Phil Pilgrim (PhiPi)

TV_Text could theoretically be rewritten to stretch the per-pixel horizontal timing for fewer, but wider, characters, and to eliminate interlacing, which would double the character height. Without interlaced characters, it would also be easier on the eyes. There are any number of people capable of making this change, but finding a subset of that group with the time and incentive to do so may be difficult.

-Phil

Ariba

@Stan671

Just set cols=20, rows=8 in the CON section of TV_Text and you have a 20x8 character display.
Then set hx=8, and vx=2 in the DAT section (tv_params) to stretch the display to the whole screen.

Andy

Phil Pilgrim (PhiPi)

Wow. 'Didn't realize it'd be that easy!

-Phil

deSilva

It's not that easy as you surely want to get rid of the interlacing, to improve the quality on 240 line displays
See my posting here of a quick and dirty change of TV_TEXT
http://forums.parallax.com/showthread.php?p=677592

Rayman

Yes, deSilva's TV_TEXT (above) looks very good on my 2.5" Parallax monitor. I have a feeling that this monitor alternates between showing top and bottom NTSC fields at 30 Hz. This causes a very annoying flicker. I think that turning interlace off effectively makes top and bottom fields the same for the monitor, getting rid of this flicker.

deSilva

Rayman said...
I have a feeling that this monitor alternates between showing top and bottom NTSC fields at 30 Hz.

This really can be, though it would be an idiotic feature an a 240 line monitor. It will be much better just to use the upper OR lower field. Which however would not work without internal memory...

Stan671

I have been working with deSilva's quick and dirty TV_Text program. It is EXACTLY what I was looking for. The 20 x 7 display is rock solid (no flickering) and certainly as readable as can be on the small display.

Since I only want to use the 20x7 arrangement in color, I have been triming down the code to be specifically for this. I have played with color combinations to get 8 colors that look good and then made inverse versions (black on colored background) for a total of 16 color possibilities for each character on the screen.

Thanks to whomever wrote the original TV_Text and to deSilva for the mods.

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Stan Dobrowski

Post Edited (Stan671) : 9/28/2007 4:01:20 AM GMT

Oldbitcollector (Jeff)

Hey Stan,

Any chance we can get you to share your final code?
Looks great!

Oldbitcollector

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Buttons . . . check. Dials . . . check. Switches . . . check. Little colored lights . . . check.

— Calvin, of 'Calvin and Hobbes.

deSilva

The changes Stan has done are most likely trivial. You should profit more from doing just the same as by copying his code
My reason for avoiding colour definitions with "chroma-on" in the MPE_TEXT driver was just that colour will decrease the display quality ... I am still experimenting with chrystals... 5 and 10 MHz are not really good...

There were some postings wrt the NTSC/PALcolour wheel:
http://forums.parallax.com/showthread.php?p=675834

Post Edited (deSilva) : 9/28/2007 4:07:17 PM GMT