Atari Mega Archive 1/Atari Mega Archive - Volume 1.iso/lists/gem/l_0799/732

Internet Message Format | 1994-08-27 | 2KB

Date: Sat, 9 Jul 1994 23:40:03 -0400 (EDT)
From: Timothy Miller <[e-mail]>
Subject: Re: Gem Listing (fwd)
To: [e-mail]
In-Reply-To: <[e-mail]>
Message-Id: <Pine.3.87.9407092303.B3776-0100000@grad>
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Goemon:

]> Who said it was difficult?  We're not talking about difficulty.  We were
]> talking about system overhead and wasted time.
]>
]> What's difficult is making a larger-than-1-pixel rectangle so that your
]> app doesn't have to be called for every mouse movement, and system time
]> doesn't have to be wasted.
]The only time this will happen is when the application is topped. If it's
]not topped, then a click in one of the windows will send an event to
]the app to "wake up".
]
]Even so, the overhead is *miniscule*. I've got it in my head to write a
]benchmark program to compare overheads of different methods, and put this
]argument to rest permanently.

You're missing the point.  If the OS has a large rectangle to compare
against, and the mouse moves, it only has to check a few numbers.  ONLY
when the OS finds the pointer entering or leaving the rectangle does it
have to go back to your program.

If you use a 1-pixel rectangle, then EVERY mouse movement goes back to
your program, and your program has to do an objc_find, EVERY TIME.

In a single-tasking environment, it doesn't matter which you do, but in a
multitasking environment, the OS having to go back to your program for
EVERY mouse movement creates a tremendous amount of overhead that is very
wasteful.  Compare running your code for every 1 mouse movement to
running your code for every 20 mouse movements.

The OS code has to run every time, but your code doesn't because it only
needs to know about certain entries/exist, and to call your EXTRA CODE
repeatedly to do nothing but realize that it needn't do anything is wasteful.