Re: [Dynapi-Help] Presentation...

Doug Melvin Thu, 25 Jan 2001 15:07:07 -0800

Not bad..

Could use some event smoothing tho..

Defination of event smoothing:

To ensure that you do not concurrent calls to your code in the event.

I.E.

say we are dragging an object. any object.

Normally in the ondragmove event you simple tell it to move itself to the current mous position.

On a high-end computer this is no problem as the event code tends to be completed before the next call..

On a slower machine tho (or with more code in the event) things start to get choppy, you grab the object,

drag it accross the screen and then sit back and wait for it to catch up with you.

(this is a problem I had with my toolbar)

There are two parts to this solution, both of which I appled.

the first is an event switch of soorts..

basically you keep track of when the code is being executed, and if the code is being executed, don't execute it again..

  if (!o.dragging){
   o.dragging=true;
   o.moveTo(e.pageX-10,e.pageY-10);
   o.dragging=false;
  }

this I found smoothed the dragging up a lot.

The next problem I found was that the test machine (a P266 with 24 megs of ram running win98)

was working WAY too hard just to drag a little dot from one end of the screen to the other.

Then I realized.. the event was being called basically as the mouse moved from one pixel to another..

This was WAY unnessesary I figured.. so, I decided that the dot should only move when the mouse has moved 5 pixels (picked that number out of the air so to speak) from it's last location..

l.ondragmove=function(e) {
  e.setBubble(false);
  var o=e.getTarget();
  if (!o.dragging&&(e.pageX-o.x>5||o.x-e.pageX>5||e.pageY-o.y>5||o.y-e.pageY>5)){
   o.dragging=true;
   o.moveTo(e.pageX-10,e.pageY-10);
   o.dragging=false;
  }
}

BTW. the 'little dot' was anouther thing I did to smooth out the dragging, bascially

fixing it so that the browser only has to redraw a 16/16 pixle area rather than the whole damned toolbar.

----

Ac ouple of more tips..

COMPRESS YER DAMNED IMAGES.. I have noted an improvment of the load-time of my demo

simply after compressing all of the images..

No, this doeas not mean loosing quality.. you will find that prodent use of gif compression can result in a WAY smaller image (one of mine whent from 2,888 bytes to 188!!)

Recomendations:

I believe that some facility for 'event capping' as I call it should be implemented into the DyAPI..

something like

l.ondragmove=function(e) {
e.setBubble(false);
e.setCapping(true); //<---------------------------------- here.

    var o=e.getTarget();
    o.moveTo(e.pageX-10,e.pageY-10);
  }
}

this would have to be implemented into events.js, and dragevents.js

Unfortunaly I am not familier with either of those files and it would be up to someone else to implement it..

Comments? Suggestions?

Doug Melvin

----- Original Message -----

From: bob basques

To: [EMAIL PROTECTED]

Sent: Thursday, January 25, 2001 1:53 PM

Subject: Re: [Dynapi-Help] Presentation...

I should relay that the finishing touches were applied by Richard.
bobb
Alan Mukamal wrote:
It *is* cool. Thanks!
-Alan
At 09:19 AM 1/25/01 -0600, you wrote:
Alan,
in exchange for your PP slides, and assuming this is something of interest,

http://64.33.167.222/work/dynapi/current.011801/setup/drag8.html

It's simple but dramatic (At least I think so.)
bobb

Re: [Dynapi-Help] Presentation...

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