FW: Re[2]: [cgmo-webcgm] Issue: addEventListener

["Ulrich Laesche" <ulrich@ematek.de>]

Sorry, I hit the wrong reply button.


-----Original Message-----
From: Benoit Bezaire [mailto:benoit@itedo.com]
Sent: Montag, 21. Marz 2005 15:58
To: Ulrich Laesche
Subject: Re[2]: [cgmo-webcgm] Issue: addEventListener

Hi Ulrich,

I was wondering if you could CC the group? I want to CC the group (I
think they should be involved). Do you mind resending, and doing a
reply all.

--
 Benoit   mailto:benoit@itedo.com


Monday, March 21, 2005, 8:15:37 AM, Ulrich wrote:

UL> Hi Benoit,

UL> Once installed, the event handler should be triggered on a Reload
Picture
UL> occurrance, right?  Still, this doesn't solve the problem you described
UL> below (unless you want to load an image twice to execute some onload
UL> actions).

UL> So far, we (Ematek) always assumed the onload event handler in the
script
UL> being present by default (like in your SVG sample).  Apparently the spec
now
UL> says that no event handler is present by default and that it needs to be
UL> installed prior to become active.

UL> We could assume that the load action is not finished before the second
line
UL> of the script is recognized (when moving the load handler to the
Metafile
UL> interface, cgmDoc.addEventListener( "load", handleLoad )).  However,
this is
UL> mere speculation and may work or not depending on the implementation or
UL> performance.

UL> What does the SVG standard propose in this respect?  As the Event
handling
UL> mechanism should work with all other events the onload should either be
UL> handled the same way (with some reasonable behavior assumptions) or
become a
UL> different method.

UL> Regards
UL> Ulrich


UL> -----Original Message-----
UL> From: Benoit Bezaire [mailto:benoit@itedo.com]
UL> Sent: Donnerstag, 17. Marz 2005 18:41
UL> To: CGMO WebCGM TC
UL> Subject: [cgmo-webcgm] Issue: addEventListener

UL> Hi CGMO,

UL>   We came upon a problem while working on addEventListener... If you
UL>   consider the following ECMAScript:

UL> <script language="JavaScript">
UL>         function handleLoad(evt)
UL>         {
UL>                 window.alert( "load finished" );
UL>         }

UL>         function init()
UL>         {
UL>                 var cgmDoc      =
UL> document.getElementById("ivx1").getWebCGMDocument();
UL>                 cgmDoc.src      = 'appstructure.cgm';
UL>                 cgmPic          = cgmDoc.firstPicture;

UL>                 cgmPic.addEventListener( "load", handleLoad );
UL>         }
UL> </script>

UL>   The problem is that the "load" event will never be triggered because
UL>   by the time you get to the addEventListener, the document is already
UL>   fully loaded.

UL>   Do people know if moving the addEventListner to the WebCGMMetafile
UL>   interface solves the problem? Ulrich, your guys worked on this,
UL>   right?

UL>   Assuming the source file was set on the <object> tag and that the
UL>   addEventListener method was on the WebCGMMetafile, would the
UL>   following code work?

UL>       function init()
UL>         {
UL>                 var cgmDoc      =
UL> document.getElementById("ivx1").getWebCGMDocument();
UL>                 cgmDoc.addEventListener( "load", handleLoad );
UL>         }

UL>   I'm thinking no... I tried this with an SVG viewer and it didn't
UL>   work (but it could be a bug). I can only get the load event to be
UL>   tricked if the event listener is already in the SVG file:
UL>   <svg onload="do something"...>

UL>   Is there a way to catch the 'load' event in a WebCGM viewer
UL>   implementation?

UL> --
UL>  Benoit                 mailto:benoit@itedo.com