Thanks everyone. But... Let me put my question another way:
on mouseUp
# lock screen -- aka "lock #1"
wait 1 second
show img 1
# unlock screen -- also part of lock #1
put the milliseconds into tStart
wait 5 milliseconds
# lock screen -- aka "lock #2"
hide img 1
#unlock screen -- also part of lock #2
put the milliseconds - tStart & cr after fld 1
set the vScroll of fld 1 to the formattedHeight of fld 1
put (the number of lines in fld 1) into fld 2
end mouseUp
I ran the above script x times and got these results on my Apple 20"
cinema display & intel mini:
- 50x with no locks/unlocks = 24% of times I saw the img
- 50x with lock #1 = 20% of times I saw the img
- 50x with lock #1 & #2 = 36% of times I saw the img
Ideally I would see the image 100% of the time - that's my goal. I'll
experiment with the other methods of displaying the image and see if I
can improve my results.
Thanks -
Phil Davis
-----Original Message-----
From: [EMAIL PROTECTED]
To: use-revolution@lists.runrev.com
Sent: Thu, 19 Apr 2007 5:19 PM
Subject: millisec test timings and screen refresh rate
I need some help here. My question is basically this: How do I
accurately track or calculate the exact moment at which an image becomes
visible on screen?
I have a client whose product is a psychological testing app, with a
battery of canned tests included. I'm reimplementing it in RunRev,
moving them away from SuperCard + a large handful of XCMDs. All the
millisecond timing used to be done in the XCMDs, but now RunRev can do
it natively, and on all platforms... wait, I don't need to sell you...
sorry. ;o)
Some tests require the Rev app to track the millisecs elapsed from when
an image is displayed on screen to when a user-initiated event occurs,
like a keypress. This means RR needs to know as precisely as possible
*when* the image became visible on screen.
(I can already hear some people shifting in their seats, muttering
"duh! just show the image, unlock screen and put the millisecs into a
variable!")
Is it that simple? I assume not. I need to figure out when the image
became visible, not when I told it to become visible. I'll need to
factor in screen refresh rate, whether testing is displayed on a CRT or
on a laptop (the normal delivery medium). This also leads me to ask: Do
laptop screens refresh the same way CRTs refresh? I doubt it.
How have you dealt with this in your RunRev experience? I bet *someone*
has dealt with this before.
Thanks in advance for all responses. This list is so great!
Phil Davis
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