Trouble with graphics display in OS X

James Hurley jhurley at infostations.com
Mon Jan 24 16:15:29 CST 2005


Last installment in my "troubles" with the display in OS X.

Following suggestions from Jacqueline, I have compared four basic 
methods of moving a RunRev control smoothly through a sequence of 
points--with mixed results.

What follows are four scripts, all of which do the same, very simple 
thing: Move a graphic 600 pixels horizontally across the screen. (I 
realize one can do this in one step, but I am looking for a general 
method to use in a library of Turtle Graphics. The path might be a 
planetary orbit, or the path of an object in game, a game which would 
involve user input. Therefore the point set cannot be determined in 
advance.)

Below I have listed the results (time in ticks) for each method. 
There are some surprising differences.

The stack generating these results can be reviewed; In the msg box:

go url "http://home.infostations.net/jhurley/DisplayProblems.rev"


Scripts:

Using: Move Relative

   put 1,0 into tRelLoc
   set the movespeed to 65535
   repeat 600
     move grc "ball" relative tRelLoc --without messages
   end repeat


Using: Set the loc

   put the loc of grc "ball" into tLoc
   repeat 600
     add 1 to item 1 of tLoc
     set the loc of grc "ball" to tLoc
     wait 0 millisec--In OS X only
   end repeat


Using: Move to the points list
(First set the moveSpeed)

  put the loc of grec "ball" into tLoc
   repeat 600
     put tLoc & return after tPoints
     add 1 to item 1 of tLoc
   end repeat
   move grc "ball" to tPoints


Using: MoveStopped
initialize tLoc to 1,0

on moveStopped
   if i < 600 then
     add 1 to i
     doMove
   end if
end moveStopped

on doMove
   move grc "ball" relative tLoc without waiting
end doMove


And the time to execute these four methods are:

OS X

Move relative, 64 ticks
Set the loc, 69 ticks --Wait 0 millisec
Move to points, 37 ticks--Or as small as 1 tick
Movestopped, 67 ticks


OS 9

Move relative, 12 ticks
Set the loc, 5 ticks--Wait 0 removed
Move to points, 37 ticks--Or as small as 1 tick
Movestopped, 12 ticks


Windows

Move relative, 309 ticks
Set the loc, 15 ticks--Wait 0 removed
Move to points, 1 ticks
MoveStopped, 321 ticks
end doMove

And the winner is: OS 9

I was astonished to discover how much slower Windows was in executing 
"Move relative" and "MoveStopped."

The only one of the four which works for me is "Set the loc". My only 
problem is the fact that it is so much slower in OS X than OS 9 or 
Windows.

Jim


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