Assign binary stream to Image object - possible?

[Sergiusz Michalski]

Hallo!!

According to my previous post with popups hanging, now I'm trying to bypass
this strange behaviour using loading JavaScript image not by image.src=URL
but straight away from stream using HTTP GET method.
The problem is, how to assign stream from downloaded image (ex. GIF89a) to a
JavaScript Image object ?

Below is my code with explanation what I'm trying to do:

<script type="text/javascript">

var xmlhttp;
/*@cc_on @*/
/*@if (@_jscript_vers ion >= 5)
var ids = ["Msxml2.XMLHTTP .5.0","Msxml2.X MLHTTP.4.0",
"Msxml2.XMLHTTP .3.0","Msxml2.X MLHTTP", "Microsoft.XMLH TTP"];
for(var i=0; !xmlhttp && i<ids.length; i++) { try { xmlhttp = new
ActiveXObject(i ds[i]); } catch(ex) { xmlhttp = false; } }
@end @*/
if (!xmlhttp && typeof XMLHttpRequest! ='undefined') { xmlhttp = new
XMLHttpRequest( ); }

if (xmlhttp) {
xmlhttp.open("G ET","http://test2/load?BINARY_ID= 42311183",true) ; //zczytuje
obrazek

xmlhttp.onready statechange=fun ction() {
if (xmlhttp.readyS tate==4) { //downloading complete!
alert(xmlhttp.r esponseText); // is OK image is loaded type is GIF89a

obrazek = new Image(); // OK
obrazek = xmlhttp.respons eBody; // this is my dream !!!!! heheh
alert(obrazek.w idth); //it's null of course, and my dream is that
obrazek.width should equal to real image readed from HTTP stream.

document.getEle mentById("docum ent_image")=obr azek; //another dream, where
document_image is an image declared in HTML body as <img
id="document_im age">

}
}
xmlhttp.send(nu ll);
}


</script>

Thanks for any help, solution, info!!!
Serge!

[Thomas 'PointedEars' Lahn]

Re: Assign binary stream to Image object - possible?

Sergiusz Michalski wrote:
[color=blue]
> obrazek = new Image(); // OK
> obrazek = xmlhttp.respons eBody; // this is my dream !!!!! heheh[/color]

Your weird writing style aside (and I don't mean the script code), this
is not your dream as you would overwrite the previously assigned object
reference `obrazek' with the value of xmlhttp.respons eBody.

What you could try is using the `data' URI scheme:

obrazek.src = "data:" + encodeURI(xmlht tp.responseBody );
[color=blue]
> alert(obrazek.w idth); //it's null of course,[/color]

It should be `undefined'. Maybe you are looking for
`xmlhttp.respon seText.length'.
[color=blue]
> and my dream is that
> obrazek.width should equal to real image readed from HTTP stream.[/color]

It cannot, since what you retrieve is a string. However, if you decode the
string, you may find out the original width of the image coded with it. Or
try

var img = new Image();
img.onload = new Function("alert (this.width);") ;
img.src = "anyURL";
[color=blue]
> document.getEle mentById("docum ent_image")=obr azek; //another dream, where
> document_image is an image declared in HTML body as <img
> id="document_im age">[/color]

Use a `data' URI and the `src' property, see above. If you use names
instead of IDs, you may use the more performant and compliant

document.images["document_image "].src
[color=blue]
> }
> }
> xmlhttp.send(nu ll);[/color]

The method does not require an argument. Sending `null' is likely to be
equal to sending nothing:

<http://msdn.microsoft. com/library/default.asp?url =/library/en-us/xmlsdk/html/xmmthsendixmlht tprequest.asp>


PointedEars

[Thomas 'PointedEars' Lahn]

Re: Assign binary stream to Image object - possible?

Thomas 'PointedEars' Lahn wrote:
[color=blue]
> What you could try is using the `data' URI scheme:
>
> obrazek.src = "data:" + encodeURI(xmlht tp.responseBody );[/color]

Err, should contain a MIME type and evaluate `responseText', for example:

obrazek.src = "data:image/png," + encodeURI(xmlht tp.responseText );


PointedEars
--
Fremd ist der Fremde nur in der Fremde.
-- Dieter Brügmann in dag° <ap97mm.3vsmp25 .1@boogie.bruha ha.de>