Livecode for Digital Signage

Wed May 18 11:52:58 EDT 2011

Thank you Chris!!
I agree that currently, any other action within the computer would translate
to a 'stutter' or 'flicker' on the ticker tape.  In my app there will be a
polling script to grab fresh data from an external db about every 5 or 10
minutes.  During the database poll, I would take the ticker stream off of
the screen so I'm not worried about any extra processing that I ask the
computer to do.

You are describing all of my problems perfectly but, at least to me, the app
is far too appealing to stop trying.  From a coding perspective, LiveCode is
all I know :-)

Every Walmart, doctor's office, Home Depot, restaurant, etc I go into I look
at the Digital Signage and say, "I can do that!"

Does anyone see a fit for animation Engine?  Will it assist in making these
types of motion consistent or 'smooth'??

jim schaubeck
714-321-4499

-----Original Message-----
From: use-livecode-bounces at lists.runrev.com
[mailto:use-livecode-bounces at lists.runrev.com] On Behalf Of Nonsanity
Sent: Wednesday, May 18, 2011 7:33 AM
To: How to use LiveCode
Subject: Re: Livecode for Digital Signage

I see your problem then. In my sample stack, the text display area is 800
pixels wide. Going by the speed you set it to, that means the text is moving
1 pixel every 4 milliseconds. No WONDER you're getting jerky motion.

With the 300 speed setting change you made, I could make it smooth by
setting the send in time delay to 10-15 milliseconds. But with the script
(simple as it is) executing that often, it is VERY susceptible to upset from
any other task running on that computer. Any delay elsewhere inside the
computer results in a visible stutter as it misses a few updates.

Also at that speed, there's an increased chance of intersecting the screen
refresh rate, which results in a momentary sheering effect along the text.
The sheer and the stutter combine to keep the text from looking solid when
moving that fast.

Tickers as seen on TV are sync-locked to the video stream, I believe, which
makes them far more stable. They are also usually on dedicated hardware and
not a home desktop computer that's running who-knows-what in the background.

I don't think you're going to be able to get that fast a speed without
temporal artifacting in LiveCode. Can you slow it down?

But even at one third that speed, you will still see the occasional sheer
(far less frequently) and some stuttering (other tasks are still running,
after all) though that is less noticeable because less distance is being
skipped at that speed..

the only way I can think of to get a sure-fire smooth scroll at ANY speed
would be to offload the work to a graphics card. Then the updates would be
synced to the display's refresh rate (no sheer) and no other tasks are
running on the graphics card CPU (so no stutter). But you can't do that in
LiveCode currently. (OpenGL support on the roadmap, anyone?)

 ~ Chris Innanen
 ~ Nonsanity

On Wed, May 18, 2011 at 1:17 AM, Jim Schaubeck
<jimschaubeck at yahoo.com>wrote:

> Chris,
> Thank you for sending your sample !!!
>
> I worked with your code a bit and changed this line:
> put dTime / 300 into pTime-- changed to 300
>
> This made the test move a similar speed (faster than your speed) to a 
> stock ticker tape but I still have the jerkiness.
>
> I will save your project for future reference though, thanks again!
>
> jim schaubeck
> 714-321-4499
>
>
> -----Original Message-----
> From: use-livecode-bounces at lists.runrev.com
> [mailto:use-livecode-bounces at lists.runrev.com] On Behalf Of Nonsanity
> Sent: Tuesday, May 17, 2011 10:05 PM
> To: How to use LiveCode
> Subject: Re: Livecode for Digital Signage
>
> Using hscroll of a field and the send in time command, I got very 
> smooth text scroll on my Macbook Pro. Here's the stack I tested with:
>
>
>
https://dl.dropbox.com/s/l4gc4mp0401j6se/Smooth%20Scrolling%20Text.livecode?
> dl=1<https://dl.dropbox.com/s/l4gc4mp0401j6se/Smooth%20Scrolling%20Tex
> t.livecode?%0Adl=1>
>
> Let me know how it works for you.
>
>  ~ Chris Innanen
>  ~ Nonsanity
>
>
>
> On Tue, May 17, 2011 at 10:28 PM, Jim Schaubeck
> <jimschaubeck at yahoo.com>wrote:
>
> > I would like to develop an in-house digital signage app that uses 
> > video, animation and smooth scrolling words (like a stock ticker).  
> > I can figure out the video and the animation but I'm having trouble 
> > with smooth scrolling text.  Is this better suited for Animation 
> > Engine (have not tried it) or is there a trick to getting text to 
> > flow Right-to-Left smoothly.  The best that I can see is the move 
> > command but it's still too jerky for displaying in a store.
> >
> >
> >
> > Thank you for any feedback
> >
> >
> >
> > jim schaubeck
> >
> > 714-321-4499
> >
> >
> >
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