[mapserver-users] Intercepting Map Click Coordinates with JavaScript ? Zooming with scale values.

[Steve Lime]

Does this actually work? I was under the impression it would IF the
image in question was in an absolutely positioned layer or it's own
frame. It's typically easy to get page coordinates but figuring out
where an image lies on the page (so you know where you are in the image)
is darn near impossible without layers or frames.

Steve

Stephen Lime
Data & Applications Manager

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937
>>> Walt Lin <joemayfair at usa.net> 01/21/02 12:18 PM >>>
With CGI, it's dirt easy-- the input type=image automatically sends
along name.x and name.y as cgi parameters.  So if you could do what you
want to server side, that's the most reliable and the easiest.

If you must do it client side, you could do something like this:
var mouseX=0,mouseY=0,setX=0,setY=0;
function getMousemove(e){
    mouseX= (bw.ns4||bw.ns6)? e.pageX:
			bw.ie&&bw.win&&!bw.ie4? (event.clientX
          	-2)+document.body.scrollLeft : !bw.opera5?
			event.clientX+document.body.scrollLeft : 
			(event.clientX-2);
    mouseY= (bw.ns4||bw.ns6)? e.pageY:
			bw.ie&&bw.win&&!bw.ie4? (event.clientY
			-2)+document.body.scrollTop : !bw.opera5?
			event.clientY+document.body.scrollTop
			 : (event.clientY-2);
};

where the bw is browser detection stuff.

On Mon, Jan 21, 2002 at 11:38:36AM -0500, Doyon, Jean-Francois wrote:
> Hello,
> 
> This is not necessarily a mpaserver specific question but ...
> 
> Is there anyway/does anybody know how to intercept the x/y pixel
coordinates
> that the user generated by clicking on the map when using the map as
an
> <input type=image> ?
> 
> I'm trying to create an interface that uses scale values to determine
the
> next up/down zoom levels, and apparently in order to do this I have to
use
> the CGI variable MAPXY, which unfortunately has to be inn the map's
> projection coordinates.
> 
> So, I need to intercept the pixel coordinates (img.x and img.y) in
order to
> do the necessary calculations and set MAPXY, all this triggered by the
> form's onSubmit ...
> 
> Anybody have any idea on how to do this? I haven't had any luck so far
using
> things like document.form.img.x ...
> 
> If worse comes to worse I guess I could use client-side maps, but I'd
rather
> not unless I absolutely have to!
> 
> Thanks in advance for the help!
> 
> Jean-Fran?ois Doyon
> Internet Service Development and Systems Support
> GeoAccess Division
> Canadian Center for Remote Sensing
> Natural Resources Canada
> http://atlas.gc.ca
> Phone: (613) 992-4902
> Fax: (613) 947-2410
> 
> 
>