FREESCO Support

by **Guy Macon** » Mon Feb 18, 2008 11:38 am

The Tux penguin screen saver has three problems; it leaves a trail behind him, it causes the screen to scroll, and the big FREESCO is still there. This leaves too many places on the screen showing the same character for too long, which will cause those characters to be burned in to a CRT screen.

The answer is:

[1] Clear the screen upon invoking the screensaver, and don't redraw anything static such as the big block that says FREESCO. If you feel a need to show an ad for FreeSCO during screensave, make it a line of text at the bottom of Tux.

[2] Have the moving penguin avoid trying to move below the bottom row or overwriting the last character of the last row, thus avoiding triggering a scroll.

[3] Make Tux larger by adding a border of space characters around him. These will overwrite the interior characters as he moves, thus erasing all trails.

--
<a href='http://www.guymacon.com' target='_blank'>Guy Macon</a>

<a href='http://www.guymacon.com/' target='_blank'>http://www.guymacon.com/</a>

by **Peppe/Sweden** » Mon Feb 18, 2008 3:14 pm

Everything that you have pointed out is features that Lightning have worked very hard to add in the latest versions.
I for one like them a lot and I wouldn't bet that Lewis would remove hours of work in any of the later releases to come.

To avoid the problem of burned in charcters in the CRT I suggest that you enabled the blank screen feature or screen saver under option 14 in the advanced menu in setup.

Regards , Peter

by **Lightning** » Mon Feb 18, 2008 8:53 pm

Hmmm there are several issue here that need to be addressed. The first is that there is a VERY good reason the penguin scrolls the screen. Which is in fact the very point you are trying to make. It helps prevent character burn in over an extended period of time by scrolling the characters off of the screen. So for that specific point I am in complete disagreement with your desires. I would also disagree with the FREESCO logo as it is displayed in random colors to help prevent burn in and finally the reason the penguin leaves a trail is because the screen is not refreshed at each movement and I had looked at it previously with removing the characters with a larger penguin of blank spaces and it did not look good to me at all.. Which as stated before that is why the screen is designed to scroll.

However I am never opposed to change and if you want to make a screen saver that looks better and works better I would be more than happy to change it. But be aware that the screen saver is a multi call script and it does a LOT more than just act as a screen saver. Which is why the extra code to make a screen saver out of it was minimal and why it is included on the floppy.

by **Guy Macon** » Tue Feb 19, 2008 2:53 am

A bit of background: I am an electronics engineer who was
involved in CRT design from the days of the mainframe
terminals until the LCDs killed all new CRT development.

I am also a huge FREESCO fan. See my post (FREESCO Rocks!) in
the compliments section or do a google search on ( guymacon
FREESCO ) to see how often I recommend it.

I had looked at it previously with removing the
characters with a larger penguin of blank spaces
and it did not look good to me at all

Can't argue with that; I am only imagining what it would
look like.

I would also disagree with the FREESCO logo as it is
displayed in random colors to help prevent burn in

there is a VERY good reason the penguin scrolls the
screen. Which is in fact the very point you are trying
to make. It helps prevent character burn in over an
extended period of time by scrolling the characters
off of the screen

...which, of course, wouldn't be there if Tux didn't leave
a trail. But again I can't argue with it not looking good
without the trail, so I agree that something has to be done.

It helps prevent character burn in over an extended
period of time by scrolling the characters off of the
screen

If you examine the screen, some locations have the middle
pixel that is part of both kinds of slashes turned on at
least 20% of the time, even with the scrolling. That will
multiply by five the time it will take for the cumulative
damage to the phosphor to cause visible burn in, but it
will still happen. A well-designed CRT screen saver shouldn't
turn on any individual pixel more than 3% of the time -- a
bit more if all the pixels get the same exposure, which is
pretty much impossible on a character-based display.

I would also disagree with the FREESCO logo as it is
displayed in random colors to help prevent burn in

By definition, color shifting static text leaves individual
pixels on at least 33% of the time. In this case, the
occasional scroll/redraw will reduce that percentage, but
not down to the desired <3% duty cycle.

BTW, I just looked at the way the screen scrolls, and the
way you are timing the character draw avoids any flicker, so
there is no need to avoid the bottom row no matter which way
you design the screensaver, and good reason not to avoid it
in the case of Tux leaving trails, so please disregard
suggestion [2].

As for Peter's suggestion, blank screens aren't as good as
screensavers in many environments such as server rooms.
A running screensaver tells you that the program is powered
up and not totally frozen.

How much work / disk space would it take to offer both
kinds of screensaver as options?

by **dilberts_left_nut** » Tue Feb 19, 2008 4:55 am

That will multiply by five the time it will take for the cumulative
damage to the phosphor to cause visible burn in, but it
will still happen.

yeah.....but people can't give away CRT's any more

if it gets burnt in pixels just grab another from the stack in the garage

by **dingetje** » Tue Feb 19, 2008 7:46 am

Isn't there a screen saver SDK somewhere so people can write their own screen saver?

by **TalkingToes** » Wed Feb 20, 2008 12:13 am

It's in / b i n / f penguin. That it uses math to bounce around to the edges is kinda cool. Is there no way to predetermine the screen size?

I used to run a BBS mid '90s and could probably come up with something simple too. The Wildcat BBS v3.9 (and v4)came with an ANSI editor that I was decent with (tho not great).

An old trick is to draw Tux with a black space around him (outside/inside each character including up/down/left/right/diagonals from each original character). Everywhere. So when moving , the black space overwites the old characters. Movment without erasing anything directly. So tux is not 7 wide, but 9 (with two black spaces outside the wings), not 5 high, but 7 high (top and bottom are 9 black spaces, the inside is black spaces too. next to his eyes are black spaces, so diagonal movement does not drag his neck too.

Thanks again for a great fun toy, err... program.

TalkingToes in Seattle

by **Lightning** » Wed Feb 20, 2008 12:29 am

Isn't there a screen saver SDK somewhere so people can write their own screen saver?

There is absolutely no limit on what screen saver you use in FREESCO. The only limitation is that it has to run on FREESCO. You can make or use a script screen saver or use any binary type of screen saver as well because the system is designed to accept any name as long as the name of the screen saver is in the PATH. So you have to place the screen saver in one of /pkg/ bin , /pkg/ sbin , or /boot/ bin directories.

My limitation as to what can be included in FREESCO however is quite a bit different and because FREESCO often runs headless in a closet somewhere even having a screen saver at all was somewhat of a debate with myself and I only decided to include it when I had it small enough and it had multiple purposes other than just being a screen saver.

I will however take a look at the fpenguin screen saver and see if it can be changed a small amount to create a more screen saver compliant application. I am doubtful I will actually change the fpenguin saver, but there could be a ftux option in the next version if it doesn't add to much code.

by **dilberts_left_nut** » Wed Feb 20, 2008 7:01 am

Lightning wrote: There is absolutely no limit on what screen saver you use in FREESCO. The only limitation is that it has to run on FREESCO.

by **Guy Macon** » Thu Feb 21, 2008 10:36 am

It it interesting that after years of use, the only suggested
improvement I could come up with was a screensaver tweak...

by **Maine-iac** » Thu Feb 21, 2008 5:23 pm

Maybe it's me, but I don't have a screen connected to Freesco.

by **Slowpoke** » Fri Feb 22, 2008 2:18 pm

Maine-iac wrote:don't have a screen connected

The Ultimate "Screensaver"!

(Sorry, couldn't help myself! :wacko: )

FREESCO Support

Improve Penguin Screen Saver

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