Livecode for Digital Signage

Wed May 18 20:41:52 EDT 2011

Thinking out loud here.

Could you take an off-screen snapshot of the formatted list and then just scroll the image at whatever speed you want?

Bill Vlahos
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On May 18, 2011, at 8:52 AM, Jim Schaubeck wrote:

> 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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