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Re: zoom problem?

From: Emmanuel Pietriga <emmanuel.pietriga@xrce.xerox.com>
Date: Mon, 25 Mar 2002 11:27:56 +0100
Message-ID: <3C9EFBAC.5050108@xrce.xerox.com>
To: Ivan Herman <ivan@w3.org>
CC: www-isaviz@w3.org
The difficulty is not actually technical. it is more a matter of 
time/priority.

As I said before, the XVTM does not allow infinite zooming. There is a 
floor, a limit  (camera_altitude=0). This problem can be addressed by 
creating bigger objects in virtual spaces, so that at this max level of 
magnification they are very big, and by initializing cameras at a higher 
altitude so that you can see objects with a "normal/standard" size.
This way you would be able to zoom in.

Now, there is no technical difficulty here. It justs means that I have 
to multiply all coordinates/sizes/font sizes by a given factor when 
importing the SVG files from Graphviz or exporting RDF models to SVG.

As the coordinates systems are different between XVTM and SVG, this is 
not straightforward. I mean, I cannot just say "multiply all coords by N".

I'll put this on the TODO list.

Emmanuel


Ivan Herman wrote:

> Emmanuel,
> 
> I understand what you say, and moving around is obviously a way. But
> think at editing any graphics with an editor, like, say Adobe
> Illustrator. I can do both there: I can pan but I can also zoom in
> vis-a-vis my default, start up view. I do not really understand why
> you consider this as a difficulty...
> 
> I.
> 
> Monday, March 25, 2002, 10:08:59, you wrote:
> 
> EP> I think I am beginning to understand. But I am not sure :)
> EP> I think the problem is that you constrain yourself by putting those 
> EP> 20-30 resources only in the region visible at the beginning, whereas you 
> EP> have a potentially infinite space at your disposal.
> 
> EP> What I suggest is : put less resources in this region. This way you'll 
> EP> get more "breathing space" for labels and all the stuff. When you have 
> EP> say 10 resources on screen at the max level of magnification, then move 
> EP> the camera slightly (for instance to the right), you'll then see empty 
> EP> space in which you can put more resources without creating a cluttered 
> EP> representation.
> 
> EP> It is the same as working with a worksapce with scrollbars. When there 
> EP> are too much things in the region, you use the scrollbars to go to 
> EP> another (empty) region of the workspace where you can put new stuff. 
> EP> here we don't have scrollbars because the workspace is infinite, so it 
> EP> wouldn't make sense. But moving the camera does the same thing.
> 
> EP> I'm not sure I'm making any sense here... Maybe it is fairly obvious and 
> EP> I'm not actually addressing your real problem. It is hard to describe 
> EP> this by e-mail.
> 
> 
> EP> Emmanuel
> 
> 
> 
> EP> Ivan Herman wrote:
> 
> 
>>>Emmanuel
>>>
>>>This is where the email method breaks ;-) To be honest, I do not understand what you do not understand (if you
>>>understand what I mean...).
>>>
>>>When the canvas is empty, I begin to put resources, labelled edges,
>>>etc and indeed everything is visible and nice. But if you get to a
>>>graph with 20-30 resources and the corresponding links, the canvas
>>>gets full. Ie, the labels get occluded, etc. So I may want to go an
>>>edit some details, ie, I would like to zoom into some detail. And that
>>>is what I cannot do.
>>>
>>>I.
>>>
>>>
>>>
> 
> 
> 
> 
> ---- 
> 
> Ivan Herman
> Head of Offices, World Wide Web Consortium
> C/o Dutch Office of W3C at CWI
> Kruislaan 413, 1098SJ Amsterdam
> The Netherlands
> tel: +31 20 5924163
> fax: +31 20 5924312
> mobile: +33 6 0887 2517
> URI: http://www.w3.org/People/all#ivan
> 
> 
> .
> 
> 


-- 
emmanuel.pietriga@xrce.xerox.com |  Xerox Research Centre Europe
Contextual Computing             |  6, Chemin de Maupertuis
tel: +33 4 76 61 50 32           |  38240 Meylan, France
fax: +33 4 76 61 50 99           |  http://www.xrce.xerox.com
Received on Monday, 25 March 2002 05:28:51 GMT

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